ILTS International Symposium on
Low Temperature Science

Program and Abstracts

30 November – 2 December 2015
Auditorium
Institute of Low Temperature Science (ILTS)
Hokkaido University

ILTS International Symposium on Low Temperature Science
30 November – 2 December 2015
Auditorium, Institute of Low Temperature Science (ILTS), Hokkaido University~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Program► Monday, 30 November 2015 ◄Plenary Session, 13:00-14:30

Chair: Gen Sazaki

13:00-13:10 Opening
Ralf Greve (Local Organizing Committee, ILTS)
Hiroyuki Enomoto (Director, Arctic Environment Research Center, NIPR)
K-01

13:10-13:50 Keynote Speech
Naoto Ebuchi (Director of ILTS)
Challenges toward a new era in low temperature science

K-02

13:50-14:30 Keynote Speech
Ilka Weikusat (AWI, Bremerhaven, Germany)
Ice physics studies in the light of global warming

Coffee Break, 14:30-15:00
Session 1. Water and Material Cycles, 15:00-18:00

Chair: Tsutomu Watanabe

1-01

15:00-15:30 Tetsuya Hiyama (Nagoya University)
Changes in hydrologic cycle under current global warming in eastern Siberia

1-02

15:30-16:10 Gabriel Katul (Duke University, Durham, NC, USA)
Optimality theories at the leaf scale and their role in regulating the hydrological cycle

1-03

16:10-16:35 Yuzo Miyazaki (ILTS)
Origin and formation mechanisms of atmospheric organic aerosols in marine and terrestrial
ecosystems

1-04

16:35-17:05 Shoshiro Minobe (Graduate School of Science, Hokkaido University)
Ocean to atmosphere influences in mid-latitudes

1-05

17:05-17:35 Hiroyuki Enomoto (NIPR / SOKENDAI, Tokyo)
Sea ice decrease in the Arctic and increase in the Southern Ocean – Discussions from the bipolar perspectives

1-06

17:35-18:00 Shigeru Aoki (ILTS)
ROBOTICA: Research of Ocean-ice BOundary InTeraction and Change around Antarcticai► Tuesday, 1 December 2015 ◄Session 2. Frontier Ice and Snow Science, 09:00-12:00

Chair: Akira Kouchi

2-01

09:00-09:25 Ayako Abe-Ouchi (University of Tokyo)
How and when to terminate the ice ages?

2-02

09:25-09:45 Fuyuki Saito (JAMSTEC, Yokohama)Development and performance of a numerical ice-sheet/shelf/stream model IcIES

2-03

09:45-10:15 Heinz Blatter (ETHZ, Switzerland)
Modelling polythermal ice sheets and glaciers

2-04

10:15-10:35 Shin Sugiyama (ILTS)
Ice mass loss in northwestern Greenland

2-05

10:35-11:00 Shuji Fujita (NIPR / SOKENDAI, Tokyo)
Recent progress in understanding densification phenomena of polar firn: textural effects andsome soluble impurities control creep deformation

2-06

11:00-11:20 Gen Sazaki (ILTS)
In-situ visualization of quasi-liquid layers on ice surfaces by advanced optical microscopy

2-07

11:20-11:40 Yuki Kimura (ILTS)
Nucleation from a supersaturated vapor

2-08

11:40-12:00 Hidekazu Tanaka (ILTS)
Homogeneous SPC/E water nucleation in large molecular dynamics simulations

Lunch Break, 12:00-13:30
Session 3. Environmental Biology, 13:30-16:30

Chairs: Mia Terashima, Atsushi Takabayashi

3-01

13:30-14:10 Wilhelm Hagen (University of Bremen, Germany)
Life history traits and ecophysiological adaptations in polar zooplankton and fish

3-02

14:10-14:35 Yasuhiro Kasahara (ILTS)
Proteome analysis of bacterial genes specifically expressed in soil

3-03

14:35-15:00 Akihiro Sumida (ILTS)
Boreal forest ecosystems as related to recent advances in ecological and physiological studiesof trees

3-04

15:00-15:25 Ryouichi Tanaka (ILTS)
Photosynthesis at low temperatures: The roles of light-harvesting-like proteins in thebiogenesis and protection of photosystems

3-05

15:25-15:50 Makio Yokono (ILTS)
PSI-PSII megacomplex in evergreen plants

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3-06

15:50-16:30 Michael Hippler (University of Münster, Germany)
Calredoxin mediates calcium- and redox-dependent regulation of photosynthesis and ROS
defense in Chlamydomonas reinhardtii

Poster Session (with coffee and tea), 16:30-18:00

Chair: Gen Sazaki

P1-01 Poonam Tyagi (ILTS / GSES)
Soil microorganisms and terrestrial plant metabolites in marine aerosols from the western
North Pacific: molecular distribution of hydroxy fatty acids over Chichijima Island
P1-02 Md. Mozammel Haque (ILTS / GSES)
Contribution of biogenic VOCs to secondary organic aerosols in Alaska atmosphereP1-03 Fumihiro Mori (ILTS / GSES)
Turbulence structure measurement in atmospheric surface layers visualized by a PIV techniqueP1-04 Haruhiko Kashiwase (NIPR, Tokyo / ILTS)
Ice-ocean albedo feedback effect on recent drastic reduction in Arctic sea ice coverP1-05 Takuya Nakanowatari (NIPR, Tokyo / ILTS)
Predictability of the Barents Sea ice in early winter: Remote effects of oceanic andatmospheric thermal conditions from the North Atlantic
P1-06 Tatsuru Sato (ILTS)
Investigation of ice-ocean interaction on Lutzow-Holm Bay, East Antarctica, from geographic,
ocean data analysis and modelingP2-01 Takashi Obase (University of Tokyo)
Antarctic ice shelves' basal melting in glacial and warm climates
P2-02 Ralf Greve (ILTS)
A simple parameterisation of ice-shelf basal melting for long-term, large-scale simulations of
the Antarctic ice sheet
P2-03 Hakime Seddik (ILTS)
Towards a GPU-accelerated ice sheet model: design philosophy and implementation
P2-04 Yoshinori Iizuka (ILTS)
Shallow ice core project on south-east dome in Greenland – Drilling report and science trenchof the ice coreP2-05 Evgeny A. Podolskiy (ILTS)
Tide-modulated seismicity in the Bowdoin glacier calving front, Northwestern GreenlandP2-06 Masahiro Minowa (ILTS / GSES)
Seasonal variations in the dynamics of Bowdoin Glacier, northwest GreenlandP2-07 Daiki Sakakibara (ILTS / GSES)
Seasonal changes in ice front position and flow speed of marine terminating outlet glaciers innorthwestern Greenlandiii

P2-08 Shun Tsutaki (NIPR, Tokyo / ILTS)
Field observations of surface mass balance, ice velocity and ice temperature on Qaanaaq ice
cap, northwestern GreenlandP2-09 Naoki Katayama (ILTS / GSES)
Elevation change of calving glaciers in northwestern Greenland analyzed by satellite data
P2-10 Naoya Morimoto (ILTS / GSES)
Surface elevation change on Trambau Glacier, Nepal Himalaya, based on remote sensing
techniques
P2-11 Ken-ichiro Murata (ILTS)
Wetting of quasi-liquid layers on ice surfaces: statics and dynamics
P2-12 Ken Nagashima (ILTS)
Liquid layers on ice surfaces induced by hydrochloric gas
P3-01 Atsushi Takabayashi (ILTS)
Evolution of photosystems in green algae through ice ages
P3-02 Mia Terashima (ILTS)
Intracellular “energy bento-box”: Flow cytometry as a method to sort microalgae and bacteria
based on cell energy reserves
P3-03 Miho Watanabe (ILTS / GSES)
Characterization of a novel sulfate-reducing bacterium possessing desulfoviridin and vibroid
morphology
P3-04 Tomohiro Watanabe (ILTS)
Diversity of sulfate-reducing and sulfur-oxidizing organisms in sediments of Antarctic lakes
P4-01 Hiroyuki Enomoto (NIPR / SOKENDAI, Tokyo)
Okhotsk study and connection to the Arctic – Sea ice, environment and life
P4-02 Akane Tsushima (NIPR, Tokyo)
Reconstruction of paleo-environmental changes in the northwestern North Pacific region froman alpine ice coreP4-03 Tatsuro Karaki (ILTS / GSES)
On the structure and dynamics of the Soya Warm Current from the viewpoint of buoyancy
arrest
P4-04 Kaoru Ito (ILTS / GSES)Interactions of internal waves and submeso-scale vortex
P4-05 Ryu Saiki (ILTS / GSES)
A mechanism of ice-band pattern formation caused by resonant interaction between sea ice andinternal waves
P5-01 Toru Takatsuka (ILTS)
Technical Support in ILTS, 2015
Reception, 18:00-20:00 (ILTS Lecture Room 215)
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► Wednesday, 2 December 2015 ◄Session 4. Research on the Pan-Okhotsk Region, 09:00-12:00

Chair: Humio Mitsudera

4-01

09:00-09:40 Takeshi Nakatsuka (RIHN, Kyoto)
Climate variations in East Asia and Japan during the last two millennia

4-02

09:40-10:20 Wonsun Park (GEOMAR, Kiel, Germany)
Predictability in the North Pacific

4-03

10:20-11:00 Teruo Aoki (MRI, Tsukuba)
Modeling of the radiative properties of snow and its application to climate study

4-04

11:00-11:30 Sumito Matoba (ILTS)
Climate changes in the North Pacific region reconstructed from alpine ice cores

4-05

11:30-12:00 Jun Nishioka (ILTS)
Biogeochemical system in the Pan-Okhotsk area

Closing, 12:00-12:15
Atsumu Ohmura (ETHZ, Switzerland)
Ralf Greve (Local Organizing Committee, ILTS)~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Note
In the above program, only the speakers are listed.
For the full list of authors, please see the corresponding abstracts.

AbbreviationsAWI
ETHZ
GEOMAR
GSES
ILTS
JAMSTEC
MRI
NIPR
RIHN
SOKENDAI

Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
Swiss Federal Institute of Technology Zurich
GEOMAR Helmholtz Centre for Ocean Research Kiel
Graduate School of Environmental Science (Hokkaido University)
Institute of Low Temperature Science (Hokkaido University)
Japan Agency for Marine-Earth Science and Technology
Meteorological Research InstituteNational Institute of Polar Research
Research Institute for Humanity and Nature
Graduate University for Advanced Studiesv

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Keynote Speeches

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K-01

Challenges toward a new era in low temperature science
Naoto Ebuchi
Institute of Low Temperature Science, Hokkaido University, Sapporo, JapanThe Institute of Low Temperature Science was founded in 1941 as the first research institute affiliatedwith Hokkaido University. The institute owes its establishment to the achievements of Dr. Ukichiro
Nakaya, professor of the department of physics, who was the first in the world to create artificial snow
crystals. Since then, our institute has achieved development in areas of basic studies on snow and ice,and natural sciences in the cryosphere. We are going to celebrate the 75th anniversary in November
2016.
In April 2010, our institute was designated as a Joint/Use Research Center of Low Temperature
Science by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. We
recognized that the main mission of the institute is to promote interdisciplinary cooperative researcheswith domestic and international research communities in parallel with proceeding high-level scientificresearches in low temperature science. To enhance international cooperation, our institute has concluded
academic exchange agreements with 21 foreign universities and research institutes in 12 countries.
Under these agreements, we promote international joint research projects pioneering a new field of low
temperature science.
In 2008, we reorganized the institute and established the Joint Research Division, which functions
as a community center for supporting joint research in low temperature science. In April 2015, five newprograms, such as “Antarctic Cryosphere-Ocean System,” “Arctic Glacier and Ice Sheet Change,”“Low-temperature Nano-material Science,” “Photosynthesis under Low Temperature Conditions,” and“The role of Pacific Marginal Seas in Linking Adjacent Lands with Oceans,” were launched as main
activities of the Joint Research Division. Under these programs, we strongly promote and support theinterdisciplinary cooperative researches challenging toward a new era of low temperature science.
Needless to say, the cryosphere plays crucial roles in the global climate system and ecosystem.
We believe that interdisciplinary researches on environmental sciences in cryosphere based on robust
fundamentals in physics and chemistry of ice and snow and biology under low temperature conditions
will significantly contribute to solve problems in the global climate changes. The programs listed above
also tackle these issues.
In addition, we recognized that education of graduate students and young scientists is also ourimportant mission for the next generation. Our institute joined the International Antarctic Institute
Program and has organized several lecture and field courses. We believe that this is a unique challengeof advanced education in the top-level international and interdisciplinary research atmosphere.

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K-02

Ice physics studies in the light of global warming
Ilka Weikusat1,2(1) Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research,
Bremerhaven, Germany(2) Department of Geosciences, University of Tübingen, Germany

Our changing climate will affect human lives in manifold ways. Especially sea-level rise is driven bydiminishing amounts of snow and land ice. The cryosphere as part of the Earth’s climate system provides
interconnecting feedbacks between its components, leading to multifaceted changes. To understandthese feedback mechanisms we have to consider the various interactions between the atmosphere, theoceans and the ice covering both polar land and seas. The state and evolution of Earth’s glaciers and ice
sheets play a key role therein and thus profound ice physics knowledge with respect to ice sheet
dynamics is required. Ice sheet dynamics on multiple scales, from microscopic processes to continentalsized phenomena, are in the focus of scientific attention to improve climate predictions on a global scale.
Snow and ice physics are mutual research interests for AWI glaciologists and ILTS researchers.
The state and evolution of ice sheets and glaciers is partly recorded in deep ice cores drilled through the
Antarctic and Greenlandic ice. Two upcoming drilling projects will further strengthen the JapaneseGerman cooperation in glaciological research: EGRIP (Greenland) focusing on questions concerning
the dynamics of ice streams and IPICS Oldest Ice (Antarctica) focusing on obtaining oldest paleaoclimate information from ice cores. Advanced analysis of ice core material can teach us the climate
history of our planet and reveal physical mechanisms leading to ice motion. Selected ice-related research
topics relevant for AWI and ILTS will be presented, as for example, the mapping of ice micro-structures,
which are reflecting the deformation and recrystallisation processes that control ice sheet flow. The
connection between ice dynamics, microstructures, and climatic changes is tackled by additional
application of palaeo-climate record methods on impurities measured in ice cores. Experiments on pureand doped ice material (e.g. with solved or insoluble chemicals and antifreeze proteins) provide better
understanding of basic processes in ice polycrystals. Process modelling as well as phenomenologicalmodelling of ice deformation then tests and completes our current understanding of ice sheet dynamics
and result in improved future projections.

-4-Session 1.
Water and Material Cycles

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1-01

Changes in hydrologic cycle under current global warmingin eastern Siberia
Tetsuya Hiyama1, Takeshi Ohta2, Ayumi Kotani2, Yoshihiro Iijima3, Hotaek Park3(1) Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan(2) Graduate School of Bioagricultural Sciences (GSBS), Nagoya University, Nagoya, Japan(3) Institute of Arctic Climate and Environment Research (IACE), Japan Agency for Marine-Earth
Science and Technology (JAMSTEC), Yokosuka, Japan

Water, energy, and carbon cycles in the Lena River basin have been investigated in plot and watershedscales from 1998 to 2013. In this presentation, seasonal, interannual, and decadal variations of water,energy, and carbon cycles in the region will be summarized with special emphasis on current global
warming. Papers listed below will be introduced and several research issues in near future will be alsosuggested. Drought - waterlogging variabilities and those effects for permafrost ecosystem in highlatitude region would be one of the critical research issues. Dynamic global vegetation models including
waterlogging processes should be strongly developed for the permafrost ecosystem.
References:
Brutsaert W, Hiyama T. 2012. The determination of permafrost thawing trends from long-term streamflow measurements with
an application in eastern Siberia. J. Geophys. Res. 117, D22110, doi:10.1029/2012JD018344.
Fedorov AN, Gavriliev PP, Konstantinov PY, Hiyama T, Iijima Y, Iwahana G. 2014. Estimating the water balance of athermokarst lake in the middle of the Lena River basin, eastern Siberia. Ecohydrol. 7, 188-196.
Hiyama T, Asai K, Kolesnlkov AB, Gagarin LA, Shepelev V. 2013. Estimation of the residence time of permafrost groundwaterin the middle of the Lena River, eastern Siberia. Environ. Res. Lett. 8, 035040, doi:10.1088/1748-9326/8/3/035040.
Iijima Y, Fedorov AN, Park H, Suzuki K, Yabuki ,H, Maximov TC, Ohata T. 2010. Abrupt increases in soil temperature
following increased precipitation in a permafrost region, central Lena River basin, Russia. Perm. Periglac. Proc. 21, 30-41.
Iijima Y, Ohta T, Kotani A, Federov AN, Kodama Y, Maximov TC. 2014. Sap flow changes in relation to permafrost
degradation under increasing precipitation in an eastern Siberian larch forest. Ecohydrol. 7, 177-187.
Kotani A, Kononov AV, Ohta T, Maximov TC. 2014. Temporal variations in the linkage between the net ecosystem exchangeof water vapour and CO 2 over boreal forests in eastern Siberia. Ecohydrol. 7, 209-225.
Ohta T, Hiyama T, Tanaka H, Kuwada T, Maximov TC, Ohata T, Fukushima Y. 2001. Seasonal variation in the energy andwater exchanges above and below a larch forest in Eastern Siberia. Hydrol. Proc. 15, 1459-1476.
Ohta T, Kotani A, Iijima Y, Maximov TC, Ito S, Hanamura M, Kononv AV, Maximov AP. 2014. Effects of waterlogging onwater and carbon dioxide fluxes and environmental variables in a Siberian larch forest, 1998-2011. Agric. For. Meteorol.
188, 64-75.
Oshima K, Tachibana Y, Hiyama T. 2015. Climate and year-to-year variability of atmospheric and terrestrial water cycles inthe three great Siberian rivers. J. Geophys. Res. Atmos. 120, 3043-3062.
Park H, Iijima Y, Yabuki H, Ohta T, Walsh J, Kodama Y, Ohata T. 2011. The application of a coupled hydrological andbiogeochemical model (CHANGE) for modeling of energy, water, and CO 2 exchanges over a larch forest in eastern Siberia.
J. Geophys. Res. 116, D15102, doi:10.1029/2010JD015386.
Park H, Fedorov A, Zheleznyak M, Konstantinov P, Walsh J. 2015. Effect of snow cover on pan-Arctic permafrost thermal
regimes. Clim. Dyn. 44, 2873-2895.
Sakai T, Hatta S, Okumura M, Hiyama T, Yamaguchi Y, Inoue G. 2015. Use of Landsat TM/ETM+ to monitor the spatial andtemporal extent of spring breakup floods in the Lena River, Siberia. Int. J. Remote Sens. 36, 719-733.

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1-02

Optimality theories at the leaf scale and their role in regulating thehydrological cycle
Gabriel Katul1,2, Stefano Manzoni3, Sari Palmroth1, Amilcare Porporato2,1,Danielle Way4, and Ram Oren1
1

Nicholas School of the Environment, Duke University, Durham, NC, USA; 2Department of Civil andEnvironmental Engineering, Duke University, Durham, NC, USA; 3Department of Physical Geography,
Stockholm University, Stockholm, Sweden; 4Department of Biology, University of Western Ontario,
London, ON, Canada
The dynamics of biological systems, from cells to communities and ecosystems, have been hypothesized
to follow optimal trajectories shaped by selection pressure that force organisms to maximize their fitness
and reproductive success. This concept has been particularly successful in explaining the form andfunction of terrestrial vegetation from eco-hydrological and carbon-economy perspectives, and acrossspatial and temporal scales. Any optimality model is based on three key ingredients: an objectivefunction that describes the gain that needs to be maximized or loss to be minimized, a control variable
that shifts the dynamics in the desired direction, and a set of constraints that account for environmental
conditions and conservation laws bounding the system. All three ingredients are difficult to define andquantify – especially in complex biological and ecological systems. Despite these difficulties,
optimality approaches may complement process-based approaches when mechanistic knowledge isscarce. At the leaf scale, it is often hypothesized that carbon gain is maximized, thus providing aquantifiable objective for a mathematical definition of optimality conditions. Eco-physiological tradeoffs and fluctuating resource availability introduces natural bounds to this optimization process. In
particular, carbon uptake from the atmosphere is inherently linked to water losses from the soil as wateris taken up by roots and evaporated. Hence, fluctuating soil moisture constrains the amount of carbon
that can be taken up and assimilated into new biomass. The problem of maximizing photosynthesis at agiven water availability by modifying stomatal conductance, the plant-controlled variable to be
optimized, has been traditionally formulated for short time intervals over which soil moisture changes
can be neglected. This simplification led to a mathematically open solution, where the undefined
Lagrange multiplier of the optimization (equivalent to the marginal water use efficiency) is heuristicallydetermined from data fitting. Here, a set of models based on different assumptions that account for soil
moisture dynamics over an individual dry-down are proposed so as to provide closed analyticalexpressions for the carbon gain maximization problem for varying soil moisture resources, atmospheric
CO2 levels, and vapor pressure deficit. Upscaling these theories to the ecosystem and exploring theirconsequences to initiation of convective rainfall is also discussed.
Reference:
Katul, G.G., S. Manzoni, S. Palmroth, and R. Oren, 2010, A stomatal optimization theory to describe the effects of atmospheric
CO2 on leaf photosynthesis and transpiration, Annals of Botany, 105(3):431-442.
Katul, G.G., R. Oren, S. Manzoni, C. Higgins, and M.B. Parlange, 2012, Evapotranspiration: A process driving mass transportand energy exchange in the soil-plant-atmosphere-climate system, Reviews of Geophysics, 50, RG3002.
Manzoni, S., G. Vico, A. Porporato, S. Palmroth, and G. Katul, 2013, Optimization of stomatal conductance for maximum
carbon gain under dynamic soil moisture, Advances in Water Resources, 62, 90-105.

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1-03

Origin and formation mechanisms of atmospheric organic aerosols
in marine and terrestrial ecosystems
Yuzo Miyazaki1, Pingqing Fu1,2, Maki Sawano1, Jinsang Jung1,3, Katsumi Yamanoi4,
Mitsuo Uematsu5, Rainer Volkamer6, Kimitaka Kawamura1(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China(3) Korea Research Institute of Standards and Science, Daejeon, South Korea(4) Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Japan(5) Atmospheric and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan(6) CIRES, University of Colorado, Boulder, CO, USA
Atmospheric organic aerosols (OAs) scatter and absorb solar and terrestrial radiation, and are involvedin the formation of clouds and precipitation as cloud condensation and ice nuclei. Marine and terrestrial
ecosystems provide substantial emissions of a variety of biogenic volatile organic compounds (BVOCs)
and subsequent formation of secondary organic aerosols (SOAs) as well as direct emissions of OAs.
However, the formation mechanisms of OAs from natural sources remain highly uncertain. This
presentation will provide an overview of our recent findings on sources and formation processes of OAs,
based on ambient OA measurements over the subarctic ocean and in cool-temperate forest environments.
On the basis of shipboard measurement of atmospheric OAs, we successfully quantified thecontribution of oceanic microbial origin to marine atmospheric OAs with methods of stable carbon
isotope analysis and organic molecular markers (Miyazaki et al., 2010). Water-insoluble fraction oforganic nitrogen was found to be the most abundant nitrogen aerosol in the subarctic western North
Pacific. This fraction of OAs was suggested to be associated with marine microbial activity and may
potentially influence the acidity, hygroscopicity, and light-absorbing properties of aerosols (Miyazaki
et al., 2011). We also found low-molecular-weight hydroxyacids in marine aerosols for the first time,
which are key intermediates for OA formation by marine microbial activity and atmosphericphotochemistry (Miyazaki et al., 2014). These findings point to the importance of ocean-derived OAs,
which control water-solubility, volatility, and light-absorbing properties of atmospheric aerosols.
Our results from several field measurements of OAs in forest environments provided aquantitative understanding of the roles of each vegetation types in the formation of biogenic OAs. They
also provided direct observational evidence of a strong temperature dependence of α-pinene-derived
SOA, and anthropogenically enhanced new particle formation and subsequent biogenic SOA formation(Miyazaki et al., 2012a; 2012b). We also proposed some new aerosol indices of biogenic origin andchemical aging of OAs to understand the mechanism of biogenic SOA formation and evolution.
Directions for future researches will be discussed on interactions between the atmosphere and biosphere
via atmospheric OAs.
References:
Miyazaki, Y. et al. 2010. Size distributions of organic nitrogen and carbon in remote marine aerosols: Evidence of marine
biological origin based on their isotopic ratios. Geophysical Research Letters, 37, L06803, doi:10.1029/2010GL042483.
Miyazaki, Y. et al. 2011. Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western
North Pacific. Atmospheric Chemistry and Physics, 11, 3037-3049.
Miyazaki, Y. et al. 2012a. Seasonal variations of stable carbon isotopic composition and biogenic tracer compounds of watersoluble organic aerosols in a deciduous forest. Atmospheric Chemistry and Physics, 12, 1367-1376.
Miyazaki, Y. et al. 2012b. Evidence of formation of submicrometer water-soluble organic aerosols at a deciduous forest site innorthern Japan in summer. Journal of Geophysical Research, 117, D19213, doi:10.1029/ 2012JD018250.
Miyazaki, Y. et al. 2014. Low-molecular-weight hydroxyacids in marine atmospheric aerosol: Evidence of a marine microbial
origin. Biogeosciences. 11, 4407-4414, doi:10.5194/bg-11-4407-2014.

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1-04

Ocean to atmosphere influences in mid-latitudes
Shoshiro Minobe
Graduate School of Science, Hokkaido University, Sapporo, Japan

In this presentation, I would like to review recent advancements of studies for ocean-to-atmosphereinfluences mainly in mid-latitudes, where I have been working on, with some discussions on theimplications to higher latitudes.

To understand how mid-latitude oceans influence the atmosphere is a long lasting problem, but highresolution satellite observations of atmospheric variables enable us to find evidences of oceanic forcings
to the atmosphere. This becomes possible by detecting patterns coherent with oceanic structures, suchas fronts and currents, in those atmospheric variables. Such detection indicates that oceanic forcing play
an important role, because scales of free-atmospheric variations are one order larger than oceanic ones.
Since this strategy utilizes the difference of spatial scales between the atmosphere and ocean, it can bereferred to as “scale-separation strategy”. I will explain how scale-separation strategy has been
employed for air-sea interaction studies in mid-latitudes using satellite data and other high resolution
outputs including atmospheric analysis and numerical modelling. Scale-separation strategy has intrinsic
imitation, but it can be overcome to some extent using other approaches such as numerical experiments.

Scale-separation strategy may works also in high-latitudes. However, observational data that can be used
for direct assessments or verification of the strategy are rather poor in high-latitudes than in mid-latitudes.
This suggests that modellings may have larger importance in high-latitude air-sea interaction studies,but of course a wise use of observational data or observational experiments are necessary for verificationof findings obtained by modelling studies.

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1-05

Sea ice decrease in the Arctic and increase in the Southern Ocean– Discussions from the bi-polar perspectives –Hiroyuki Enomoto1,2(1) National Institute of Polar Research, Tokyo, Japan(2) The Graduate University for Advanced Studies, Tokyo, Japan

Arctic and sub-Arctic sea ice conditions show general tendencies of decrease, however sea ice in theSouthern Ocean shows increase. As sea ice coverages in the Arctic and Southern Ocean are showing
both common and different seasonal, long-term trends, bi-polar perspective will be important forunderstanding sea ice change in the consequence of global climate change.
Both variations were considered to be occurring under the influence of global warming. There arecommon and different characteristics in the Arctic and Antarctic:
Common aspects:− Changes in polar region− Phenomena in sea ice and/or cryospheric and polar components− Ice area changes associated with thickness change− Driving by dynamic conditions− Concerns on snow coverDifferent aspects:− Decreasing or increasing in sea ice− Arctic or Antarctic− Summer or winter− Seasonal march− Long-term trend− Climate influences and feed backs
Sea ice map often focuses extreme condition of sea ice and seasonal march and long-term trend.
Sea ice data is indicated usually separated in the Arctic or Antarctic. This study tried to put together andsummarized characteristics of their extent, seasonal differences, seasonal march and long-term trends.
Arctic sea ice was thick and their mobility was not large, however recent decrease of ice area is making
new condition of Arctic sea ice. Sea ice in the Arctic is showing high mobility in summer and also
evidenced even in winter season. Recent study introduces importance of sea ice dynamics for the ice
thickness change in the Arctic.
Sea ice area around Antarctic Continent can be separated in to several zones by latitude and season.
Ice dynamics are important factor in the Antarctic sea ice change due to its high mobility. Relationships
between sea ice and snow condition are also of interest.
As the available data base, Arctic Data archive System (ADS) was developed in the GRENE
Arctic project. Same as in situ data in the Arctic research field, satellite data was archived in the ADS.
JAXA is supporting Arctic project by providing satellite data. The satellite data archiving andvisualization tools are expanded to the Antarctic data. ADS is covering bi-polar data. ADS has the datavisualization tool “VISHOP” can indicate multi-data on the projection.

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1-06

ROBOTICA: Research of Ocean-ice BOundary InTeraction andChange around Antarctica
Shigeru Aoki1, Takeshi Tamura2, Team ROBOTICA(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) National Institute of Polar Research, Tokyo, JapanThe unique characteristics of interactions among climate subsystems in East Antarctica have recently
been revealed, and evidence of variations on various time scales - from decades to millennia - have been
accumulating. Beneath the Totten Glacier Ice Shelf off Wilkes Land, ice discharge is accelerating, anda new potential pathway of warm water access has been discovered (Greenbaum et al., 2015). At the sametime, coastal polynyas are ubiquitous along the East Antarctic coast. Sea ice formation and subsequentbrine rejection in polynyas, including Cape Darnley and Vinceness Bay Polynyas, result in the
production of Dense Shelf Water and lead to the export of bottom water (Ohshima et al., 2013; Kitade
et al., 2014). Changes in the icescape, such as a Glacier Tongue calving, have a significant impact on
oceanic conditions, changes in sea ice production, and the subsequent formation of Dense Shelf Water(Tamura et al., 2013; Kusahara et al., 2013). The environment is quite different in the neighborhood of
the Lützow-holm Bay off Enderby Land, where Japan has maintained a year-round station ever since
the IGY era. Coastal polynyas are rare here, but fast ice develops and the icescape varies from year toyear. A trace of oceanic temperature variability on decadal time scale has been observed, anddisintegration/stabilization of the landfast ice and Shirase Glacier Tongue have a quasi-periodicity of
one to two decades.
ROBOTICA is initiated to understand the wide range of ice-ocean interactions and long-term
variabilities off the East Antarctic Coast. For the coming 9th six-year plan (2016-2023) of the Japanese
Antarctic Research Expedition (JARE), we plan to implement broad under-ice oceanographic,
geographical, and cryospheric surveys using ROV/UAVs, sustained oceanographic observations using
tethered and moored profiling platforms, and an ice-surface network of ice/ocean motion anddeformation using GPS/ GNSS. Combining such new technologies with conventional and robust
observational techniques will enable us to acquire more detailed environmental information, both intime and space. Applying these remote observation techniques to insufficiently explored regions will
enhance our understanding of the mechanisms of different ice-ocean interaction regimes. In cooperation
with the international research community, ROBOTICA will contribute to the development of the future
observational network.
References:
Greenbaum, J.S., and 10 coauthors, Ocean access to a cavity beneath Totten Glacier in East Antarctica. Nature Geoscience, 8,294-298, 2015.
Kitade, Y., and 9 coauthors, Antarctic Bottom Water production from the Vincennes Bay Polynya, East Antarctica, Geophys.
Res. Lett., 41, 3528-3534, doi:10.1002/2014GL059971, 2014.
Ohshima, K.I., Y. Fukamachi, G.D. Williams, and 10 coauthors, Antarctic Bottom Water production by intense sea-ice
formation in the Cape Darnley Polynya, Nature Geoscience, doi:10.1038/ngeo1738, 2013.
Tamura, T., et al., Potential regime shift in decreased sea ice production after the Mertz Glacier calving, Nature comm.,
doi:10.1038/ncomms1820, 2012.
Kusahara, K., H. Hasumi, and G.D. Williams, Impact of the Mertz Glacier Tongue calving on dense water formation and export,
Nature comm., doi:10.1038/ncomms1156, 2011.

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Session 2.
Frontier Ice and Snow Science- 13 -

- 14 -

2-01

How and when to terminate the ice ages?
Ayako Abe-Ouchi
Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan

Climate change with wax and wane of large Northern Hemisphere ice sheet occurred in the past 800
thousand years characterized by 100 thousand year cycle with a large amplitude of sawtooth pattern,following a transition from a period of 40 thousand years cycle with small amplitude of ice sheet change
at about 1 million years ago. Although the importance of insolation as the ultimate driver is now
appreciated, the mechanism what determines timing and strength of terminations are far from clearly
understood. Here we show, using comprehensive climate and ice-sheet models, that insolation andinternal feedbacks between the climate, the ice sheets and the lithosphere-asthenosphere system explain
the 100,000-year periodicity. The responses of equilibrium states of ice sheets to summer insolation
show hysteresis, with the shape and position of the hysteresis loop playing a key part in determining theperiodicities of glacial cycles. The hysteresis loop of the North American ice sheet is such that after
inception of the ice sheet, its mass balance remains mostly positive through several precession cycles,
whose amplitudes decrease towards an eccentricity minimum. The larger the ice sheet grows and extends
towards lower latitudes, the smaller is the insolation required to make the mass balance negative.
Therefore, once a large ice sheet is established, a moderate increase in insolation is sufficient to triggera negative mass balance, leading to an almost complete retreat of the ice sheet within several thousand
years. We discuss further the mechanism which determine the timing of ice age terminations byexamining the role of astronomical forcing and change of atmospheric carbon dioxide contents throughsensitivity experiments and comparison of several ice age cycles.

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2-02

Development and performance of a numericalice-sheet/shelf/stream model IcIES
SAITO Fuyuki1, Ayako ABE-OUCHI2,1, Kunio TAKAHASHI1(1) Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan(2) Atmosphere Ocean Research Institute, University of Tokyo, Kashiwa, Japan

Ice sheet model for Integrated Earth-system Studies (IcIES) has been developed to simulate past andfuture ice sheets evolution. The model adopts the shallow ice approximation for grounded part, theshallow shelf approximation for floated part, and optionally adopts Schoof (2007) parametrization forcomputing grounding-line flux. Recent development and application of IcIES to various topics are
introduced.

Because of strong non-linearity in the governing equation, large computing resources are demanded tosolve the equation with high accuracy. Practically, truncation at some stage has to be decided on thebasis of the balance between available computer resources and numerical accuracies, especially for longterm application. This study presents impact on the ice-sheet/shelf simulation of various time scales bydifferent technical details such as a convergence criteria in the matrix solver, under ideal and realistic
configuration including Antarctic ice sheet.

Many ice cores are drilled at present ice domes, the ice core sites may not necessary have been the“summit” throughout the time of interest. To help interpretation of the ice core analysis possible change
in the simulation of the position of the summits by numerical modelling can be a vulnerable information.
Sensitivity experiments are performed to evaluate how the position reacts to the boundary conditions
such as local bedrock topography and ice-sheet margin using IcIES.

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2-03

Modelling polythermal ice sheets and glaciersHeinz Blatter1,2, Ralf Greve1(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland

Ice sheets and glaciers may be temperate or cold; however, most of them are always or at least
temporarily polythermal with both cold and temperate regions. In cold ice, a change in energy content
leads to a change in temperature, whereas in temperate ice, it leads to a change in the content of liquidwater. Between the different regions, there is a cold-temperate transition surface (CTS), either withmelting conditions if cold ice flows into the temperate region, or with freezing conditions if temperate
ice flows into the cold region.
In order to model the thermal structure of polythermal ice sheets accurately, energy-conserving
schemes and correct tracking of the CTS are necessary. Various models include a polythermal scheme;a two-layer polythermal scheme was implemented in SICOPOLIS (Greve, 1997), Aschwanden andBlatter (2005, 2009) applied a trajectory model to compute the water content in the temperate zone andAschwanden et al. (2012) introduced a one-layer scheme based on enthalpy to track the melting CTS inice sheets.
We compare four different thermodynamics solvers in the ice sheet model SICOPOLIS. A twolayer polythermal scheme and a single-phase cold-ice scheme already existed. Two one-layer enthalpy
schemes, namely a conventional scheme and a melting-CTS scheme (Blatter and Greve, 2015) wereadded. The comparison uses two scenarios of the EISMINT Experiments (Payne et al., 2000). In termsof temperate ice layer thickness, CTS positioning and smoothness of temperature profiles across the
CTS, the polythermal two-layer scheme performs best, and thus its results are used as a reference against
which the performance of the other schemes is tested. Both the cold-ice scheme and the conventional
one-layer enthalpy scheme fail to produce a continuous temperature gradient across the CTS, and both
overpredict temperate ice layer thicknesses. In the one-layer melting-CTS enthalpy scheme, acontinuous temperature gradient is explicitly enforced, and results match those obtained with thepolythermal two-layer scheme well.
References:
Aschwanden, A. and H. Blatter (2005). Meltwater production due to strain heating in Storglaciären, Sweden. J. Geophys. Res.,
110(F4), F04024 (doi: 10.1029/2005JF000328).
Aschwanden A. and H. Blatter (2009). Mathematical modeling and numerical simulation of polythermal glaciers. J. Geophys.
Res., 114(F1), F01027 (doi: 10.1029/2008JF001028).
Aschwanden, A., E. Bueler, C. Khroulev and H. Blatter (2012). An enthalpy formulation for glaciers and ice sheets. J. Glaciol.,58(209), 441–457 (doi: 10.3189/2012JoG11J088).
Blatter, H. and R. Greve (2015). Comparison and verification of enthalpy schemes for polythermal glaciers and ice sheets witha one-dimensional model. Polar Sci., 9(2), 196–207 (doi: 10.1016/j.polar.2015.04.001).
Greve, R. (1997). A continuum-mechanical formulation for shallow polythermal ice sheets. Phil. Trans. R. Soc. Lond. A,
355(1726), 921–974 (doi: 10.1098/rsta.1997.0050).
Payne, A. J. and 10 others (2000). Results from the EISMINT model intercomparison: the effects of thermomechanical coupling.
J. Glaciol., 46(153), 227–238 (doi: 10.3189/172756500781832891).

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2-04

Ice mass loss in northwestern Greenland
Shin Sugiyama1, Shun Tsutaki1,2, Daiki Sakakibara1,3, Jun Saito1,3, Yoshihiko Ohashi1,3,
Mihiro Maruyama1,3, Naoki Katayama1,3, Evgeny Podolskiy1, Masahiro Minowa1,3, Takanobu
Sawagaki4, Sumito Matoba1, Martin Funk5, Riccardo Genco6,(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Arctic Environment Research Center, National Institute of Polar Research, Tokyo, Japan(3) Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan(4) Faculty of Social Sciences, Hosei University, Tokyo, Japan(5) Laboratory for Hydraulics, Hydrology and Glaciology, ETH-Zurich, Switzerland(6) Department of Earth Science, University of Florence, Italy
The Greenland ice sheet and peripheral ice caps are losing ice mass (e.g. Khan and others, 2015).
Overview of the mass change has been revealed over the last decade thanks to the advance in satellite
remote sensing techniques, but more detailed studies are needed to understand controlling mechanisms,
and spatial and temporal variations of the mass loss. Recently, mass loss is increasing particularly along
the coast in northwestern Greenland (Enderlin and others, 2014). Despite the importance of this region,
in-situ data are sparse in northern part of Greenland.
To quantify ice mass loss in northwestern Greenland and better understand the mechanisms
driving ongoing changes in this region, we have been working on the ice sheet and glaciers in the
Qaanaaq region, as a part of GRENE Arctic Climate Change Research Project. Field and satellite
observations were performed on the ice sheet, outlet glaciers and ice caps. We also performed ocean
measurements to better understand ice-ocean interaction. These studies include mass balance and ice
speed monitoring on Qaanaaq Ice Cap since 2012, integrated field observations and hot water drillingnear the calving front of Bowdoin Glacier since 2013, and ocean measurements near the front of
Bowdoin Glacier and in other fjords in the region.
Our data showed that the glaciers and ice caps are losing mass at increasing rates. Ice caps arethinning at a rate >1 m a−1, which is significantly greater than previously reported estimate. Rising air
temperature is the primary reason of this change, but ice surface darkening due to biological activity
also enhances ice melt in the ablation area (Sugiyama et al., 2014). Calving glaciers are retreating,thinning, and accelerating as reported in southern Greenland. Initial retreat of the glaciers is probably
due to atmospheric and/or oceanic warming, but successive rapid changes are driven by glacier
dynamics controlled by ocean and glacier bed geometry (Sugiyama et al., 2015). These results indicatedthe rapid changes in northwestern Greenland, and therefore the importance of continuous observationsin the future. Particularly, it is urgent to study more details of oceanic changes to accurately understandthe ongoing change and its impact on human society in Qaanaaq region. In this contribution, we present
these results of the GRENE Greenland project, and introduce the next project planned under theframework of ArCS (Arctic Challenge for Sustainability Project).
References:Enderlin, E. M., I. M. Howat, S. Jeong, M. J. Noh, J. H. van Angelen, and M. R. van den Broeke, 2014. An improved mass
budget for the Greenland ice sheet. Geophysical Research Letters, 41, 866–872.
Khan, S. A., A. Aschwanden, A. A. Bjørk, J. Wahr, and K. H. Kjær. 2015. Greenland ice sheet mass balance: a review. Reports
on Progress in Physics, 78, 046801.
Sugiyama, S., D. Sakakibara, S. Tsutaki, M. Maruyama and T. Sawagaki. 2015. Glacier dynamics near the calving front of
Bowdoin Glacier, northwestern Greenland. Journal of Glaciology, 61(226), 223–232.
Sugiyama, S., D. Sakakibara, S. Matsuno, S. Yamaguchi, S. Matoba and T. Aoki. 2014. Initial field observations on Qaanaaq
Ice Cap in northwestern Greenland. Annals of Glaciology, 55(66), 25–33.

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2-05

Recent progress in understanding densification phenomena ofpolar firn: textural effects and some soluble impurities control
creep deformation
Shuji Fujita1, 2, Motohiro Hirabayashi 1 and Kumiko Goto-Azuma1, 2(1) National Institute of Polar Research, Tokyo, Japan(2) Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI)

For observation of the polar ice sheets under the ongoing global warming, understanding the evolutionof polar firn is fundamental to better understand (i) ice core signals, (ii) surface elevation changes ofpolar ice sheets and (iii) data of microwave remote sensing of polar ice sheets. Metamorphism and initiallayering of snow is known to be dependent on various surface conditions, such as the accumulation rate,
temperature, temperature gradient, and mechanical forcing by wind. After the initial processes of firn
formation at the ice sheet surface, firn subsequently undergoes various further processes of both
metamorphism and deformation with both increasing time and depth. Such processes, including initial
fractures, rearrangement of ice grains, creep deformation, pressure sintering with shrinkage of either
pore spaces or closed air bubbles, and grain growth, are complex. Our knowledge is still limited toreliably model the densification phenomena of polar firn for various applications.
To improve our understanding, firn cores drilled at several sites at Dome Fuji in the East Antarctic
Plateau, and an inland site of Greenland called NEEM were investigated, using surrogates of density:dielectric permittivities ε v and ε h at microwave frequencies with electrical fields in the vertical and thehorizontal planes, respectively. Dielectric anisotropy ∆ε (= ε v - ε h ) was then examined as a surrogate of
the anisotropic geometry of firn. In addition, major ions were measured to investigate effects of impurity
ions. We found that layered densification is explained as a result of complex effects of two independent
phenomena that commonly occur at the investigated sites. Basically, layers with initially smaller density
and smaller geometrical anisotropy deform preferentially throughout the densification process due totextural effects. Here, the textural effects include ice-ice bonding, c-axis orientation fabrics andgeometrical structure of ice and pore spaces. Second, layers having a higher concentration of Cl- ion, ahigher concentration of F- ions or a smaller concentration of NH 4 + ions deform preferentially. We
hypothesize that sites of oxygen within crystal lattice of ice are substituted by these ions dissociatedfrom sea salts or mineral dusts, and that these ions modulated dislocation movement. Moreover, firn
differs markedly between the investigated sites in terms of strength of geometrical anisotropy, mean rateof densification, and density fluctuation. We hypothesize that these differences are caused by texturaleffects resulting from differences in depositional conditions within various spatial scales.
Overall, actual densification of polar firn and ice is dominantly controlled by creep deformation
associated with the dislocation motion at wide depths from the ice sheet surface to deeper (~100m)
depths. Our observed features are apparently different from the traditional view that the firn densification
phenomena is a sequence of several stages such as; (i) initial fractures, (ii) rearrangement of ice grains,and (iii) creep deformation. In future, firn densification models need more focus on creep deformation
mechanism throughout the densification process.

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2-06

Prism and other high-index faces of ice crystals exhibit two types ofquasi-liquid layers
Harutoshi Asakawa*, Gen Sazaki, Ken Nagashima, Shunichi Nakatsubo, Yoshinori Furukawa
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan* Present address: Dept. Creative Technol. Eng., Anan National College of Technology, Anan, Japan

Surface melting of ice significantly governs a wide variety of phenomena in nature, such as thegeneration of thunder, regelation, frost heave, the conservation of foods, ice-skating, the preparation ofa snowman and crystal growth of ice. We recently succeeded in directly observing the surface melting
on ice basal faces by our advanced optical microscopy, which can detect 0.37-nm-thick elementary steps
on basal faces [1]. Then we found, on basal faces, that two types of quasi-liquid layers (QLLs) appear:
drops and thin layers [2]. However the direct observation of surface melting on the other prism and highindex faces remains an experimental challenge. To fully obtain comprehensive understanding, we needto examine the surface melting on these faces. Here we show the appearance of two types of QLLs also
on prism and high-index faces just below the melting point [3].
It is well acknowledged that thermal roughening occurs on an ice prism face at temperatureshigher than –2°C: an ice prism face becomes rounded and high-index faces appear in this temperature
range. We first observed the thermal roughening processes of ice prism faces in situ, and found that thethermal roughening needs a time scale of about one hour. Then next, we quickly raised a temperature ofice crystals and then observed prism and high-index faces during the roughening process. We found thatwith increasing temperature, round liquid-like droplets (α-QLLs) first appeared at temperatures higher
than –1.4 ~ –0.5°C, and then thin liquid-like layers (β-QLLs) also appeared at temperatures higher than–0.8 ~ –0.3°C, as in the case of basal faces. This result demonstrates that the presence of two types of
QLL phases with different morphologies plays an intrinsically important role in the surface melting of
ice crystals, irrespective of face indexes. We also revealed that the roughening process was caused
thermally.

Fig. 1. A summary of the main findings on prism and high-index faces in this study (A) and thoseon basal faces in our previous study [1] (B). Schematic illustrations show cross sectional views.

References:1) G. Sazaki, S. Zepeda, S. Nakatsubo, E. Yokoyama, Y. Furukawa, "Elementary steps at the surface of ice crystals visualized
by advanced optical microscopy", Proc. Nat. Acad. Sci. USA., 107, 19702-19707 (2010).
2) G. Sazaki, S. Zepeda, S. Nakatsubo, M. Yokomine, Y. Furukawa, "Quasi-liquid layers on ice crystal surfaces are made up
of two different phases", Proc. Nat. Acad. Sci. USA., 109, 1052-1055 (2012).
3) H. Asakawa, G. Sazaki, K. Nagashima, S. Nakatsubo, Y. Furukawa, "Prism and other high-index faces of ice crystals exhibit
two types of quasi-liquid layers", Crystal Growth & Design, 15, 3339-3344 (2015).

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2-07

Nucleation from a supersaturated vapor
Yuki Kimura1, Kyoko K. Tanaka1, Kouchi Akira1, Naoki Watanabe1, Shunichi Nakatsubo1,
Shinnosuke Ishizuka1, Yuko Inatomi2(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Institute of Space and Astronautical Science, JAXA, Sagamihara, Japan

In the current universe, cosmic dust particles have mainly been produced in gas out flow from dying
stars such as asymptotic giant branch stars and super novae. It is not easy to form a particles via
homogeneous nucleation, which is a process to overcome a free energy barrier for phase transition
without an assistance of a substrate. Gas atoms or molecules are condensed on a substrate, called
heterogeneous nucleation, much more efficiently than homogeneous nucleation. Therefore, pre-existing
dust is able to work as a substrate for heterogeneous nucleation of remaining gas species. One of our
motivation is to know what kind of mineral firstly nucleates around dying stars, because first dust works
as a substrate for heterogeneous nucleation of remaining gases. Since nucleation process determinescharacters, such as size, size distribution, composition, crystalline structure and morphology, of final
products, first dust is essential in the process of material evolutions accompanying with stellar life.
We know homogeneous nucleation can be occurred far from thermal equilibrium. However, we
do not know how far it is. The efficiency for nucleation strongly depends on the materials. Particularly,
surface free energy and sticking probability are the most important physical parameters to predict
nucleation. Unfortunately, however, these physical parameters have large uncertainties, because actual
size of dust is less than 100 nm in diameter and the nucleation processes are progressed in nanometerscale. These physical parameters should be different from that of the bulk. Nevertheless, generally,
bulk values have been used. To evaluate the formation sequences of minerals and find the character andformation condition of first dust, we are trying to reproduce cosmic dust particles in our laboratory andobserved the nucleation environment to determine above mentioned two physical parameters (Kimura
et al. 2011, 2012).
Another important aspect is the difference of the formation condition between natural cosmic dust
particles and mimic laboratory dust. Ordinarily, our knowledges have been accumulated by groundbased experiments and the formation and alteration processes of cosmic materials have been discussed
based on such knowledges. However, natural cosmic dust particles form under microgravity condition,
where surface tension contributes more strongly and gravity effects, such as weight and convection, aresuppressed. Therefore, we believe that understanding of the microgravity effects and difference between
on earth and in universe on the material formation is required to make clearer view of the formation ofmaterials in space. Therefore, we have performed microgravity experiments in parabolic flights using
airplane and sounding rockets (Kimura et al. 2014). Here we will show our results showing how large
supersaturation is required for homogeneous nucleation and how formation of cosmic dust particles isdifficult.
References:
Kimura, Y., H. Miura, K. Tsukamoto, C. Li and T. Maki. 2011. Interferometric in-situ observation during nucleation and growthof WO 3 nanocrystals in vapor phase. Journal of Crystal Growth, 316, 196-200.
Kimura, Y., K. K. Tanaka, H. Miura and K. Tsukamoto. 2012. Direct observation of the homogeneous nucleation of manganesein the vapor phase and determination of surface free energy and sticking coefficient. Crystal Growth & Design, 12 (6), 32783284.
Kimura, Y., K. K. Tanaka, I. Sakon, T. Nozawa, H. Miura, K. Tsukamoto, S. Takeuchi and Y. Inatomi. 2014. Nucleation
Experiment of Cosmic Dust under Microgravity using a Sounding Rocket S-520-28. Int. J. Microgravity Sci. Appl., 31 (3),130-136.

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2-08

Homogeneous SPC/E water nucleationin large molecular dynamics simulations
Hidekazu Tanaka1, Kyoko K. Tanaka1, Raymond Angélil2, Jürg Diemand2(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Institute for Computational Science, University of Zurich, Zurich, Switzerland

We perform 18 runs of direct large molecular dynamics simulations of homogeneous SPC/ E water
nucleation with the LAMMPS code for various vapor temperatures and number densities, using up to~ 4 x 106 molecules. Our large system sizes allow us to measure extremely low and accurate nucleation
rates, down to ~1019 cm−3 s−1 from ~1024 cm−3 s−1 in the previous simulations. Our results help the fillingof the gap to experimentally measured rates ~1017 cm−3 s−1. We are also able to precisely measure size
distributions, sticking efficiencies, cluster temperatures, and cluster internal densities. To obtain accurate
steady nucleation rates from simulations with the Yasuoka-Matsumoto nucleation rate measurement
technique, we introduce a new fitting functional form, by taking into account a lag time before the steady
nucleation. Comparison to nucleation models shows that classical nucleation theory over-estimates
nucleation rates by a few orders of magnitude. The semi-phenomenological nucleation model does better,under-predicting rates by at worst a factor of ~20, as well as in the laboratory experiments. Unlike what
has been observed in Lennard-Jones simulations, post-critical clusters have temperatures consistent withthe run average temperature. Also, we observe that post-critical clusters have densities very slightly
higher, ~5%, than bulk liquid. We re-calibrate a Hale-type J-S scaling relation using both experimental
and simulation data, finding remarkable consistency in over 30 orders of magnitude in the nucleation
rate range and 180 K in the temperature range (see the figure).

Figure: Nucleation rates J as function of
lnS/(T/T c -1)1.7 for MD simulations andlaboratory experiments. In the horizontal
axis, S is the super-saturation ratio and T cis the critical temperature. MD simulations
are plotted with filled circles (present
work[1]) and crosses (previous work[2]).
Various experimental data are plotted withsquares. The thin curves show the SP model.

References:[1] Angelil, R., Diemand, J., Tanaka, K. K., and Tanaka, H. 2015. Homogeneous SPC/E water nucleation in large molecular
dynamics simulations. Journal of Chemical Physics 143, 064507.
[2] Tanaka, K.K., Kawano, A. and Tanaka, H. 2014. Molecular dynamics simulations of the nucleation of water: determining
the sticking probability and formation energy of a cluster. Journal of Chemical Physics 140, 114302.

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Session 3.
Environmental Biology- 23 -

- 24 -

3-01

Life history traits and ecophysiological adaptationsin polar zooplankton and fish
Wilhelm Hagen
BreMarE Bremen Marine Ecology, Bremen University, Bremen, Germany

Polar zooplankton species exhibit quite diverse life history traits. A major driving force determining
their life strategies is the seasonal variability in food supply, which is most pronounced at high latitudes,
where fluctuations in primary production are extreme. Therefore, seasonal adaptations are closely
related to the trophic level of zooplankton species, with strongest environmental pressures occurring on
herbivorous organisms. The dominant grazers, calanoid copepods and krill (Euphausiacea), havedeveloped fascinating solutions for successful overwintering at higher latitudes during the dark period,
when primary production is at a minimum. These herbivores usually exhibit a very efficient storage andutilization of energy reserves to reduce the effect of a highly seasonal primary production. The
predominant larger Calanus species from the Arctic and Calanoides acutus from the Antarctic
biosynthesize large amounts of high-energy wax esters. These compounds consist of unusual long-chain
monounsaturated fatty acids and alcohols (20:1 and 22:1 isomers) as major components. They survive
the winter period at depth in a stage of dormancy called diapause. In contrast, the Antarctic Calanus
propinquus, a winter-active species, synthesizes primarily triacylglycerols, which are dominated bylong-chain monounsaturated fatty acids with 22 carbon atoms (2 isomers) and yield even higher calorificcontents. Herbivorous copepods usually channel this energy towards reproductive processes in late
winter/early spring. They do not utilize much of their enormous lipid reserves for maintenance during
overwintering, as does the Antarctic krill, Euphausia superba, which stays active in winter andreproduces rather late in the summer season. Timing of reproduction is critical especially at highlatitudes due to the short primary production period, and lipid reserves often ensure early spawning
independent of external resources. These energetic adaptations (dormancy, lipid storage) aresupplemented by other life strategies such as extensive vertical migrations, change in the mode of life,
and trophic flexibility. Omnivorous and carnivorous species, which are less subjected to seasonal foodshortage, usually do not exhibit such an elaborate lipid biosynthesis.
The carnivorous pelagic Antarctic silverfish, Pleuragramma antarctica, is an exception from thisrule, as this fish species permanently accumulates massive amounts of triacylglycerols in special lipid
sacs during its early ontogenetic development. However, in this dominant fish species, which lacks aswim bladder, the lipids primarily function as buoyancy aid rather than energy reserve.

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3-02

Proteome analysis of bacterial genes specifically expressed in soil
Hajime Morimoto1,a, Ryosuke Kadoya1,b, Yasuhiro Kasahara1(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
Present addresses: (a) Hokkaido System Science Co., Ltd., Sapporo(b) Graduate School of Engineering, Hokkaido University, Sapporo
Bacterial cells living in natural soil environments respond to physical, chemical and biological changes.
Knowing the gene expression pattern, function, and physiological state of a single bacterial strain is
important for understanding of bacterial ecology. To clarify the gene expression and functional data foreach of bacteria from special habitats, general information has been obtained through in vitro studies
under various conditions. However, the information would considerably differ for bacteria exposed tovarious environmental factors in the original soil habitat. Particularly, genes specifically expressed insoil and not in laboratory media are considered to provide important information.
We performed differential proteomics analysis using a standard sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS–PAGE) technique, combined with liquid chromatographytandem mass spectrometry (LC–MS/MS), and identified Pseudomonas putida F1 genes specifically
expressed in soil. The strain F1 was inoculated into three different types of soil (soybean, maize, andforest) and incubated for 3 days, and also cultured to logarithmic and stationary phase in rich andminimal media, and the proteome datasets were compared. For the genes specifically expressed in soil,
their expression stimuli were identified.
From comparative analyses of the proteome datasets, 187 distinct proteins were differentiallydetected in the three soil samples, not detected in liquid samples. Among those, nine proteins were foundto be commonly detected in all three samples. Finally, seven genes were identified as specifically
expressed in soil, including two genes coding for a hypothetical protein and a nitric oxide dioxygenase,respectively, and a cluster consisting of five genes. The expression factor analysis revealed that the genecoding for nitric oxide dioxygenase was induced by nitric oxide, and five clustered genes were induced
under phosphate starvation.
These results suggest that our soil metaproteome approach is useful for understanding the
autecology and lifestyle of a single bacterial strain in soil environment, and that it allows the predictionof the microenvironment surrounding the bacterial cells.

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3-03

Boreal forest ecosystems as related to recent advances inecological and physiological studies of trees
Akihiro Sumida
Institute of Low Temperature Science, Hokkaido University, Sapporo, JapanThe boreal forest occupies ca. one-third of the total forest area on Earth. Diversity of dominant plant
species is low, and a large amount of carbon is stored in the soil. How the boreal forest ecosystem may
respond to global warming is of concern. As trees in the cold region naturally have the ability to survive
the winter environments of their native habitats, their responses to the environment in the growing
season (summer) are more relevant than those in winter. In this presentation, some of the recent advancesin ecological and physiological studies of the boreal forest and forests in cold regions are introduced byfocusing on studies at individual-tree levels.
One of the noticeable recent advances relates to symbiotic interaction between trees and somegroups of fungus in the soil called mycorrhizas. About 90% of tree species observed have been found
to retain mycorrhizas on the surface of or inside of their fine root tips. Mycorrhizas provide trees withsoil nutrients such as nitrogen in return for non-structural carbohydrates (NSC) soluble in water, theproduct of the photosynthesis by trees. However, further studies revealed that in harsh environments
where resources are difficult to obtain as in cold environments, the symbiotic activity of mycorrhizas
may be opportunistic (Näsholm et al. 2013). On the other hand, it had long been assumed that the major
factor limiting growth of trees was the amount of NSC within a tree body. This assumption has beenquestioned as many recent studies have demonstrated that NSC exist somewhere in a tree bodythroughout the year, and that the amount of NSC is enough to meet current-year growth of a tree (Salaet al. 2012). The findings have given rise to revisions of the factors limiting tree growth and the relevanceof NSC for trees.
Plants retain a large amount of enzyme protein called RuBisCO, the key enzyme limiting
photosynthesis, within their leaves. In winter, evergreen trees in the cold region have known toaccumulate a certain amount of inactive RuBisCO more than necessary for their photosynthesis during
winter. This seemingly inexplicable phenomenon is regarded as trees' adaptation to nitrogen-limiting
environments; nitrogen is a major element composing RuBisCO. The nitrogen stored in the RuBisCO
in older leaves is remobilized to newly developing leaves in spring (Millard et al. 2010). When the airtemperature increases in the spring of a cold region, the soil temperature cannot increase as fast as the
air temperature. Hence activities of roots to absorb soil nutrients are low in early spring. The
remobilization of nitrogen from old to new leaves in early spring could serve for producing new leaves
as early as possible in spring, and for increasing the duration of photosynthesis in the growing season ina cold region.
As these examples demonstrate, recent physiological and ecological knowledge of trees relates
not only to the above-ground processes but also to the below-ground ones, and suggest concretemechanisms of the interactions between them in relation to physical environments of cold regions.
Incorporating the knowledge as stated above into ecosystem-level analyses could lead to better
understanding of the boreal forest ecosystem.
References:
Millard, P. and Grelet G-A. 2010. Nitrogen storage and remobilization by trees: ecophysiological relevance in a changing world.
Tree Physiology 30, 1083-1095.
Näsholm, T., Högberg, P., Franklin., O., Metcalfe, D., Keel, S.G., Campbell, C., Hurry, V., Linder, S., and Högberg, M.N.
2013. Are ectomycorrhizal fungi alleviating or aggravating nitrogen limitation of tree growth in boreal forests? New
Phytologist 198, 214-221.
Sala A. Woodruff, D.R., and Meinzer, F. C. 2012. Carbon dynamics in trees: feast or famine? Tree Physiology 32, 764-775.

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3-04

Photosynthesis at low temperatures: The roles of light-harvestinglike proteins in the biogenesis and protection of photosystems
Ryouichi Tanaka1, Fumiyoshi Myouga2, Kazuo Shinozaki2, Yukako Kato1, Kaori Takahashi1,
Yuki Akiyama1, Kei Sakata1, Makio Yokono1, Atsushi Takabayashi1 and Ayumi Tanaka1(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science,
Yokohama, JapanAt low-temperatures, many metabolic processes in plants are slowed down. As a consequence, theenergy captured by photosynthesis is not sufficiently consumed within cells, which ultimately results inuncontrolled oxidation of proteins, lipids and other biological molecules. It is hypothesized that plants
in the boreal regions adopt several strategies to avoid such destructive oxidation of biological molecules
under low-temperature conditions. In particular, evergreen trees must have effective methods to copewith temperature-induced damages.
Gene expression analyses of evergreen trees indicate that they express specific sets of genes
encoding chloroplast proteins in wintertime. It is plausible that those genes are involved in the protection
or maintenance of photosystems in wintertime. Among them, those encoding Light-harvesting-like(LIL) proteins are of particular interests, because some of the LIL proteins are reported to be interactingwith the photosynthetic machinery under the conditions where the machinery is prone to damages.
Here, we report our investigation on the function of representative LIL proteins in the model plant,
Arabidopsis thaliana. We found that a member of LIL proteins, LIL3, forms a stable complex with
geranylgeranyl reductase (GGR) which catalyses the formation of phytyl-diphosphate, a key
intermediate in chlorophyll, tocopherol and phylloquinone biosynthesis. For better understanding of thefunction of the LHC motif in LIL3, we have modified the LIL3 and GGR sequences and analyzed theeffects of these modifications in transgenic Arabidopsis plants. When the membrane-spanning domainsof LIL3 were fused with GGR, GGR was stabilized in the absence of LIL3. The results indicate thatanchoring GGR to membranes is a main function of LIL3.
LIL8 (alternatively called PBS33) is another LIL protein in thylakoid membranes. We foundthat lack of LIL8 leads to an altered excitation balance between PSI and PSII. It is likely that LIL8 isinvolved in the control of excitation balance between these photosystems. Taken together, it is foundthat multiple LIL proteins are involved in photosynthesis-related functions.
LIL2 (alternatively called OHP1) is a thylakoid protein with a single membrane-spanning domain.
Its amino acid sequence is similar to that of cyanobacterial Hlip proteins which are involved in theassembly of photosystem (PS) II. The Arabidopsis ohp1 mutant lacking LIL2 has a reduced level of
PSII. Purification of a protein complex containing LIL2 from Arabidopsis leaves revealed that LIL2
forms a complex with LIL6, and other components that are similar to the cyanobacterial proteins in the
Hlip complex. These results suggest that plants have a PSII-assembling system similar to the
cyanobacterial one.
Taken together, it is indicated that LIL proteins are involved in the biogenesis and regulation ofphotosystems. The functions of LIL proteins might be essential in the overwintering of evergreen trees.

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3-05

PSI-PSII megacomplex in evergreen plants
Makio Yokono1, Atsushi Takabayashi1, Seiji Akimoto2, Ayumi Tanaka1(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Molecular Photoscience Research Center, Kobe University, Kobe, Japan

Traditionally, two types of photosystem reaction centers (PSI and PSII) are thought to be spatiallydispersed. However, we showed that about 60% of PSIIs are physically connected to PSIs, and formed
PSI-PSII megacomplex in Arabidopsis thaliana [1]. PSII can transfer excess excitation energy directly
to PSI, then the excess energy was quenched by PSI. This mechanism is very important to deal withexcess excitation energy, then we focus on non-model photosynthetic organisms to reveal diversity ofthe mechanism.
In evergreen species, excess excitation energy is very severe problem. While plant looks green,
red- and blue-light are absorbed, and the excitation energy is continuously generated. Under a mild
climate, the excitation energy is converted to electron flow in the PSI and PSII, and the electron is used
to fix CO2. However, under low temperature, electron flow is inhibited, and most excitation energy
becomes excess. Plant should convert the excess excitation energy to heat immediately, because theexcitation energy easily change its character (~10-7 sec.) and causes cell death. Here, we report how
evergreen species utilize the PSI-PSII megacomplex.
We analyzed three species, Yew tree, Birthroot, and Black pine. The former two were harvested
in campus of Hokkaido University, and the latter one was harvested in campus of Kobe University. In
summer, all species utilized the PSI-PSII megacomplex, and the excitation energy dynamics looked thesame to in A. thaliana. Next, we examined seasonal change of the PSI-PSII megacomplex in Yew tree.
In winter Yew needles, we also observed the PSI-PSII megacomplex, where PSII transfer its
excitation energy to PSI. However, PSI showed different fluorescence property, which reflects modified
PSI antenna in winter Yew tree. Previously, we reported that Yew tree showed seasonal change incharacter of PSI antenna [2]. In summer, the PSI antenna showed similar character to A. thaliana. In
winter, the PSI antenna showed different fluorescence peak as observed in this study. The modified PSI
showed higher ability to convert excitation energy to heat. Therefore, in winter, Yew tree transferredexcess excitation energy from PSII to PSI, then PSI may convert the energy to heat efficiently by themodified PSI antenna.
The winter Yew needles showed drastic change when the needles transfer to 20 ℃ condition.
After 1 h, the modified PSI antenna in the winter Yew needles was detached from reaction centers, whilemost PSII may still bind to PSI. Yew tree may switch over from defense mode to photosynthesis modeby detachment of the modified PSI antenna from PSI-PSII megacomplex.
References:[1] M. Yokono, A. Takabayashi, S. Akimoto, A. Tanaka. 2015. A megacomplex composed of both photosystem reaction centres
in higher plants. Nature Communications, 6, 6675.
[2] M. Yokono, S. Akimoto, A. Tanaka. 2008. Seasonal changes of excitation energy transfer and thylakoid stacking in theevergreen tree Taxus cuspidata: How does it divert excess energy from photosynthetic reaction center?. Biochimica etBiophysica Acta, 1777, 379-387.

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3-06

Calredoxin mediates calcium- and redox- dependent regulation ofphotosynthesis and ROS defence in Chlamydomonas reinhardtii
Ana Karina Hochmal1&, Karen Zinzius1&, Ratana Charoenwattansatien2&, Philipp Gäbelein1,
Risa Muto2, Hideaki Tanaka2, Stefan Schulze1, Gai Liu3, Andre Nordhues1, Martin Scholz1,
Dimitris Petroutsos4, Giovanni Finazzi4, Kaiyao Huang3, Genji Kurisu2, Michael Hippler1(1) Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany(2) Institute of Protein Science, Osaka University, 5650871 Suita Osaka, Japan(3) Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences,
Wuhan, Hubei, 430072, China(4) Centre National Recherche Scientifique, Unité Mixte Recherche 5168, Laboratoire Physiologie
Cellulaire et Végétale, F-38054 Grenoble, France& Contributed equally

Calcium (Ca2+) and redox signaling play important roles in acclimation processes from archaea toeukaryotic organisms. Herein we characterized a unique protein from Chlamydomonas reinhardtii thathas the competence to integrate Ca2+ and redox-related signaling. This protein, originally identified in a
proteomic study (Hohner et al., 2013), was designated as calredoxin (CRX), as it combines four Ca2+binding EF-hands and a thioredoxin (TRX) domain. A protein crystal structure of CRX, at 1.6 Å
resolution, revealed an unusual calmodulin-fold of the Ca2+-binding EF-hands, which is functionallylinked via an inter-domain communication path with the enzymatically active TRX domain. CRX ischloroplast-localized and interacted with a chloroplast 2-Cys-peroxiredoxin (PRX1). Ca2+-binding to
CRX is critical for its TRX activity and for efficient binding and reduction of PRX1. Thereby CRX
represents a new class of Ca2+-dependent "sensor-responder" proteins. Genetically engineered
Chlamydomonas strains with strongly diminished amounts of CRX, revealed altered photosynthetic
electron transfer and impact in ROS defense underpinning a function of CRX in stress acclimation.
Reference:
Hohner, R., Barth, J., Magneschi, L., Jaeger, D., Niehues, A., Bald, T., Grossman, A., Fufezan, C., and Hippler, M. (2013).
The metabolic status drives acclimation of iron deficiency responses in Chlamydomonas reinhardtii as revealed by proteomics
based hierarchical clustering and reverse genetics. Molecular & cellular proteomics: MCP 12, 2774-2790.

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Session 4.
Research on the Pan-Okhotsk Region- 31 -

- 32 -

4-01

Climate variations in East Asia and Japan during last two millennia
Takeshi Nakatsuka
Research Institute for Humanity and Nature

Recently, high resolution datasets on past climate, annually-resolved past temperature and precipitation,
have been created using tree rings all over East Asia including Japan for last few millennia. Althoughtree growth is not controlled by temperature in warm regions, it is sensitive to summer temperature incold regions. Because pattern of temporal variation in temperature is quite similar within a wide area of
East Asia, past summer temperature reconstructed by Tibetan and/or Mongolian trees can be applied toestimate past change in average temperature in East Asia including Japan. By compiling all available
tree ring datasets in Asia, Cook et al (2013) successfully reconstructed average summer temperaturesince 800 CE at annual time resolution in East Asia. Reconstructed temperature variation in East Asia
was arrayed with those in other continents over world to illustrate spatio-temporal variability intemperature during last two millennia (PAGES 2k consortium, 2013). Characteristics in combined
temperature variations beyond continents are as follows. (1) Temperature had been gradually decreasing
until 19th century all over world. (2) Except for Antarctica, temperature had suddenly become to increasein 20th century. (3) There were not any universal decades or centuries of “Medieval Warm Period” or“Little Ice Age” in the world except for some cold episodes following large volcanic eruptions and/or
solar minima. All indicate the serious influence of human-emitted greenhouse gases to the climate after
20th century.
Contrary to temperature, it has been difficult to estimate past change in precipitation in pluvial
region like Japan. It is not only because tree growth in humid area is not influenced by precipitation, butalso because spatial distribution of precipitation is more heterogeneous than that of temperature so that
it is impossible to infer precipitation history in pluvial areas using tree-ring data in continental arid
region. This difficulty has been solved by utilization of tree-ring oxygen isotope ratio, a consistentdendrochronological parameter which can tell us past variations in summer precipitation precisely. In
Japan, we have reconstructed past summer precipitation back to 4300 years ago in annual time resolution
at several sites using various kinds of wood such as living trees, old architectural wood, excavatedarchaeological wood and buried natural logs. Tree-ring oxygen isotope ratios have been unraveling past
precipitation history in East and Southeast Asia, too (Xu et al., 2003). The oxygen isotope ratios havebeen increasing recently all over Asia monsoon region, suggesting that Asia summer monsoon has
become weaker (drier) due to the increased tropical sea surface temperature.
In fact, the reconstructed variations in temperature and precipitation have apparent tight
relationships with historical and archaeological records, such that amplifications in multi-decadal
climate variability, i.e. occurrence of decadal length of drought, flood or coldness, often resulted innotorious famines and/or warfare in Japan and Asia. Because of preciseness in the newly obtained
paleoclimate data, we can start interdisciplinary studies on climate-society relationship in human history
by direct collaborations between historians, archaeologists and paleoclimatologists in the world.
References:
Cook, E. R., P. J. Krusic, K. J. Anchukaitis, B. M. Buckley, T. Nakatsuka, M. Sano and PAGES Asia2k Members. 2013. Treering reconstructed summer temperature anomalies for temperate East Asia since 800 C.E. Climate Dynamics, 41, 29572972 doi:10.1007/s00382-012-1611-x41.
PAGES 2k consortium. 2013. Continental-scale temperature variability during the last two millennia, Nature Geoscience, 6,339-346.
Xu, C., M. Sano and T. Nakatsuka. 2013. A 400-year hydroclimate variability and local ENSO history in northern Southeast
Asia inferred from tree-ring δ18O, Palaeogeography, Palaeoclimatology, Palaeoecology, 386, 588-598.

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4-02

Predictability in the North PacificWonsun Park, Yanling Wu, Guidi Zhou, Mojib Latif, Richard Greatbatch
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany

North Pacific sector climate exhibits variability on a wide range of time scales, from interannual tocentennial. Predictability is related to both internal climate variability and external forcing, where
respective contributions can be time scale dependent. Here we focus on a multiyear predictability
generated by internal variability. As ocean-atmosphere interaction is heavily involved in this process,identifying related ocean process, its generation mechanism and atmospheric response to the ocean
signal are important. We present level of predictability naturally existing in the North Pacific climate
system (Wu et al. 2015) and sensitivity of atmosphere model in representing the response to ocean
anomalies (Zhou et al. 2015).
We first examine multiyear predictability of Northern Hemisphere surface air temperature (SAT)
in a multi-millennial control integration of the Kiel Climate Model, a coupled ocean–atmosphere–sea
ice general circulation model. Multiyear SAT predictability exists near the sea ice margin in the North
Atlantic and mid-latitude North Pacific sector. In the North Pacific, the most predictable SAT pattern ischaracterized by a zonal band in the western and central mid-latitude Pacific, which is linked to the sea
surface temperature (SST) anomalies that are associated with re-emergence processes. Pacific Decadal
Oscillation (PDO) driven SST anomalies subduct into deeper ocean layers and re-emerge at the sea
surface during the following winters, providing multiyear memory.
We further show, by means of dedicated high-resolution atmospheric model experiments, thatdaily variability in the extratropical background SST needs to be resolved to force a statisticallysignificant large-scale atmospheric response to North Pacific SST anomalies. The large-scale responseis mediated by atmospheric eddies.
References:
Wu, Y., M. Latif, and W. Park. 2015. Multiyear predictability of Northern Hemisphere surface air temperature in the Kiel
Climate Model. Climate Dynamics, in press.
Zhou, G., M. Latif, R.J. Greatbatch, and W. Park. 2015. Atmospheric Response to the North Pacific Enabled by Daily Sea
Surface Temperature Variability. Geophysical Research Letters, 42, DOI 10.1002/2015GL065356.

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4-03

Modeling of the radiative properties of snow and its application toclimate study
Teruo Aoki1, Masashi Niwano1, and Sumito Matoba2(1) Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Snow and ice conditions are presently undergoing drastic changes, which is significant in the Arctic andmid-latitude cryosphere. For understanding and predicting the climate change in the cryosphere, thedetailed observational studies and physically based modeling studies on snow physical parameters(albedo, solar heating profile, snow height, temperature, density, grain size, shape, liquid water content,
impurities, etc.) are needed. Among them surface albedo is a key factor of heat budget in cryosphere.
The near-infrared (NIR) albedo mainly depends on snow grain size (Wiscombe and Warren, 1980) andthe visible albedo on concentrations of light absorbing snow impurities (LASI) (Warren and Wiscombe,1980). We developed a physically based snow albedo model (PBSAM, Aoki et al., 2011) for generalcirculation models that simulates broadband albedo and the solar heating rate in the snowpack fromsnow physical parameters and solar illumination conditions. The PBSAM is incorporated into snow
metamorphism and albedo process model (SMAP, Niwano et al., 2012) by which snow grain size andthe other snow parameters are calculated. PBSAM was validated with the snow pit and albedo datameasured during 5 winters from 2006 to 2011 in study plot of Institute of Low Temperature Science,
Hokkaido University, Sapporo, Japan. The root mean square error of shortwave albedo calculated with
PBSAM was 0.069. The estimated albedo reduction (radiative forcing) due to LASI (black carbon [BC]and mineral dust) by PBSAM were 0.055 (6.6 Wm-2). The contribution to albedo reduction from BC
was much larger (77%) than dust (23%). SMAP simulated that the recent snowpack durations at Sapporo
were shortened by 16-19 days caused by LASI during the 2007–2009 winters. These models have been
incorporated into earth system model of Meteorological Research Institute. The models can beapplicable to simulation of albedo and snow microphysics on a stand-alone as well.
References:
Aoki, T., K. Kuchiki, M. Niwano, Y. Kodama, M. Hosaka, and T. Tanaka, 2011: Physically based snow albedo model for
calculating broadband albedos and the solar heating profile in snowpack for general circulation models, J. Geophys. Res.,
116, D11114, doi:10.1029/2010JD015507.
Niwano, M., T. Aoki, K. Kuchiki, M. Hosaka, and Y. Kodama, 2012: Snow Metamorphism and Albedo Process (SMAP) model
for climate studies: Model validation using meteorological and snow impurity data measured at Sapporo, Japan, J. Geophys.
Res., 117, F03008, doi:10.1029/2011JF002239.
Warren, S. G. and W. J. Wiscombe, 1980: A model for the spectral albedo of snow, II: Snow containing atmospheric aerosols,
J. Atmos. Sci., 37, 2734–2745, doi:10.1175/1520-0469(1980)037<2734:AMFTSA>2.0.CO;2.
Wiscombe, W. J. and S. G. Warren, 1980: A model for the spectral albedo of snow: I. Pure snow, J. Atmos. Sci., 37, 2712–
2733, doi:10.1175/1520-0469(1980)037<2712:AMFTSA>2.0.CO;2.

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4-04

Climate changes in the North Pacific region reconstructed fromalpine ice cores
Sumito Matoba1, Akane Tsushima2, Takayuki Shiraiwa1, Osamu Seki3, Yoshinori Iizuka3,
Kimitaka Kawamura3(1) Pan-Okhotsk Research Center, Inst. of Low Temperature Science, Hokkaido Univ., Sapporo, Japan(2) National Institute of Polar Research(3) Institute of Low Temperature Science, Hokkaido Univ.

Ice cores obtained from glaciers and ice sheets are one of the most important archives of paleo-climaticand paleo-atmospheric information. Variations in chemical signals in ice cores can be used as indicatorsof past air temperature, annual precipitation rate, source area of water vapor, and many other parameters.
In the mid- and low latitudes, suitable locations for ice-core drilling are limited to the high-elevationsites of alpine glaciers, where the effects of snowmelt in summer on chemical signals in ice cores are
not significant. Generally, accumulation rate in the drilling sites of the alpine ice cores is much higher(more than 1m water eq.) than inland ice sheet site (e.g. Dome Fuji in Antarctica and GRIP in Greenland),and ice thickness of the alpine ice core site is approximately 100 to 300 m. Therefore, the time ranges
intended by alpine ice core studies are several hundred years. Noteworthy climate change events forseveral hundreds in the North Pacific region are the Little Ice Age, recent global warming, the Pacific
Decadal Oscillation and so on.
We have obtained several ice cores in the North Pacific region to reconstruct the changes inclimate and environment in this region. On the Asian side, we have drilled in the Kamchatka Peninsula,
Russia, at Ushkovsky mountain in 1998 and Ichinsky mountain in 2006. On the North American side,
we have drilled in Alaska, at Mount Wrangell in 2003 and 2004 and at the flat saddle north of Aurora
Peak in 2008.
Reconstructed annual accumulation at Aurora Peak showed a significant increase from 1970s to
the present at the rate of 28 mm/yr. This significant trend of increase has not been observed at any
meteorological stations at ground level. Annual accumulation at Mount Wrangell showed high values
before 1977, low values from 1977 to 1990, and high values after 1990 again. The variation of
accumulation in 1977 is likely associated with the climatic shift called Regime Shift. The annual
accumulation in the Wrangell ice core after 1990 anti-correlated with surface level pressure over the
Gulf of Alaska. The variations of accumulation rates likely associate with the intensity of low pressure
systems in the Gulf of Alaska and Bering Sea.
We also analyzed several kinds of chemical substances in the ice cores such as organic compounds,
soluble salt and heavy metals as new tracers for the records of environmental changes. We will also
brief the results of new tracers.
References:
Fukuda, T., S. Sugiyama, S. Matoba and T. Shiraiwa. 2011. Glacier flow measurement and radio-echo sounding at Aurora
Peak, Alaska in 2008, Ann. Glaciology, 58, 138-142.
Matoba, S., K. Shimbori and T. Shiraiwa. 2014. Alpine ice core drilling in the North Pacific region, Ann. Glaciol., 55(68), 8387, doi:10.3189/2014AoG68A020.
Pokhrel, A., K. Kawamura, O. Seki, S. Matoba and T. Shiraiwa. 2014. Ice core profiles of saturated fatty acids (C12:0-C30:0)
and oleic acid (C18:1) from southern Alaskan since 1734 AD: A link to climate change in the Northern Hemisphere, Atmos.
Environ., 100, 202-209, doi:10.1016/j.atmosenv.2014.11.007.
Tshusima, A., S. Matoba, T. Shiraiwa, S. Okamoto, H. Sasaki, D. J. Solie and K. Yoshikawa. 2015. Reconstruction of recent
climate change in Alaska from the Aurora Peak ice core, central Alaska, Clim. Past, 11, 217-226, doi:10.5149/cp-11-217-2015.

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4-05

Biogeochemical system in the Pan-Okhotsk area
Jun Nishioka
Pan-Okhotsk Research Center, Institute of Low Temperature Science,
Hokkaido University, Sapporo, Japan

Iron (Fe) is an essential nutrient and plays an important rolls in the control of phytoplankton growth andbiogeochemistry in the Ocean. The subarctic Pacific is known to have High Nutrient Low Chlorophyll(HNLC) area, where nutrient concentrations are not depleted through all season and the phytoplankton
growth is broadly limited by Fe availability. However, even with the Fe limitation, the western subarctic
Pacific (WSP) has effective phytoplankton growth and more seasonality in the lower trophic levels thanthe eastern subarctic Pacific. Therefore, differences in Fe supply processes must explain the west-toeast decrease in seasonal phytoplankton growth. Although we recognize several Fe supply processes in
the WSP, the mechanisms that account for controlling phytoplankton growth have not been understood.
Here we demonstrate the pivotal role of marginal sea, the Okhotsk Sea, system for suppling Fe to the
Pacific Ocean. A basin-scale Fe section shows that sedimentary Fe is discharged from the Okhotsk Sea
to the western North Pacific in the intermediate layer. The re-distribution of this Fe-rich intermediatewater by intensive mixing as it crosses the Kuril Island Chain (KIC) is the predominant process
determining the ratio of micro-nutrient to macro-nutrients in subsurface waters. This ratio canquantitatively explain the differences in surface macro-nutrient consumption between the western andeastern subarctic, as well as the formation of the HNLC region in the North Pacific. Therefore, theexistence of a sub-polar marginal sea that connects with the North Pacific through the KIC is essential,
and diapycnal mixing in the KIC is a key process, for controlling the Fe supply and the seasonal
amplitude of the biogeochemical cycle in the WSP. This natural Fe fertilizing system simultaneously
explains one of the largest biological pumps in the world [Buesseler et al., 2007] and the formation of
the HNLC region in the WSP [Tsuda et al., 2003].
Recent weakening of overturning in the intermediate water in this system has been reported[Nakanowatari et al., 2007]. Clarifying what causes these long-term changes of oceanic physical andbiogeochemical conditions is an essential step for predicting future global climate changes. Our findings
contribute to predicting of the future changing of the biogeochemical cycles in the North Pacific.
References:
Buesseler, K. O., et al, 2007, Science, 316, doi:10.1126/science.1137959.
Tsuda, A., 2003, Science, 300, 958-961.
Nakanowatari, T., K.I. Ohshima, and M. Wakatsuchi, 2007, Geophys. Res. Lett. 34, L04602, doi:10.1029/2006GL028243.

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- 38 -

Poster Session- 39 -

- 40 -

P1-01

Soil microorganisms and terrestrial plant metabolites in marine
aerosols from the western North Pacific: molecular distribution ofhydroxy fatty acids over Chichijima Island
Poonam Tyagi1,2, Hayato Yamaguchi1,2, S. K. R. Boreddy2, S. K. Verma2 and Kimitaka Kawamura2(1) Graduate School of Environmental Sciences, Hokkaido University, Japan(2) Institute of Low Temperature Sciences, Hokkaido University, Japan

Air- and soil-borne microorganisms can be pathogenic to humans and can cause severe allergies during
their atmospheric transport. Several studies have been conducted to measure bacteria associated withdust and their health impacts [Griffin, 2007 and references therein]. However, atmospheric researchers
face difficulties in the identification and quantification of these pathogenic bacteria during their longrange atmospheric transport. To solve this, hydroxy FAs, specifically β-isomers, can serve as themarkers for bacteria and plant metabolites during their atmospheric transport over the Pacific. Alongwith β-hydroxy FAs, other α- and ω-isomers of these hydroxy FAs have also been employed as tracer
for soil microorganisms such as bacteria, fungi as well as for algae and higher plants in airborne
particulate matter.
Hydroxy fatty acids (FAs) were measured in the aerosol samples collected from Chichijima Island(27°04'N; 142°13'E) in the western North Pacific during January 2001–January 2003. These fatty acids
showed a clear seasonal variation with winter/spring maxima and summer/autumn minima along withan even C-number predominance. This seasonal pattern clearly indicates their atmospheric transport
from the continents during winter/spring and from the ocean in summer/autumn. Further, inwinter/spring we found good correlations between hydroxy FAs and biomass burning tracers such as
levoglucosan and nss-K as well as with nss-SO 4 ions. This suggests that hydroxy FAs are co-transportedwith dust and biomass burning plumes from the Asian continent to the remote marine island via
westerlies during winter/spring. Moreover, cluster analysis showed that spring and winter seasons arecharacterized by the aeolian transport of hydroxy FAs from North China, Korea, Russia, and Mongolia.
Their terrestrial sources include higher plant metabolites as well as soil- and air-borne microorganisms(bacteria, fungi, yeasts, etc.). In contrast, during summer/autumn 2001, we observed good correlations
between ω-hydroxy FAs and Cl and Mg ions. Additionally, α- and β-hydroxy FAs in summer/autumn
2002 were well correlated with methylsulfonic acid (MSA) and ammonium (NH 4 ) ions. As wind pattern
shifts during summer/autumn, hydroxy FAs are brought from the sea to the island and their sources
include algae, cyanobacteria and other marine phytoplankton.
Overall, continental sources overwhelm hydroxy FAs in the atmospheric particles over
Chichijima Island than marine sources. Our results indicated that hydroxy FAs (specific Gram- negative
bacterial tracers) are adhered to soil particles and transported long distances over the western North
Pacific and can be further carried to the central Pacific. These results have implications towards
assessing the atmospheric transport of bacterial and plant lipids in the continental outflow over the open
ocean.
Reference:
Griffin, D. W. (2007). Atmospheric movement of microorganisms in clouds of desert dust and implications for human health,Clinical microbiology reviews, 20(3), 459-477.

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P1-02Contribution of biogenic VOCs to secondary organic aerosols in the
Alaskan atmosphere
Md. Mozammel Haque1,2, Kimitaka Kawamura1 and Yongwon Kim3
1

Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
3
International Arctic Research Center, University of Alaska Fairbanks, USA

2

Organic constituents are recently highlighted because they account for a substantial portion of
atmospheric particles up to 50% in mass and potentially influence the hygroscopic properties, affecting
the earth climate, air quality and public health. Biogenic secondary organic aerosol (SOA) is asignificant portion of atmospheric trace gases and aerosols. SOA is produced via the oxidation ofbiogenic volatile organic compounds (BVOCs) with O 3 , OH and NO 3 radicals (Atkinson and Arey,
1998). Vegetation can release substantial amounts of BVOCs, including isoprene, monoterpenes,
sesquiterpenes and oxygenated hydrocarbons.
Total of 32 total suspended particle (TSP) samples were collected in Fairbanks, Alaska from
June 2008 to June 2009 using a low volume air sampler. Here, we report the molecular characterizationof isoprene-, α-/β-pinene- and β-caryophyllene-SOA tracers, which were measured using solvent
extraction/TMS-derivatization technique followed by gas chromatography-mass spectrometry (GC-MS)
determination. The concentration ranges of isoprene, α-/β-pinene and β-caryophyllene oxidation
products were 0.02-18.6 ng m-3 (ave. 4.14 ng m-3), 0.42-8.24 ng m-3 (2.01 ng m-3) and 0.10-9 ng m-3(1.53 ng m-3), respectively. Isoprene-SOA tracers showed higher concentrations in summer (ave. 8.77
ng m-3), whereas α-/β-pinene- and β-caryophyllene-SOA tracers exhibited highest levels in spring (3.55
ng m-3) and winter (4.04 ng m-3), respectively. β-Caryophyllinic acid and levoglucosan showed a positive
correlation, indicating that biomass burning may be a major source for β-caryophyllene. The meancontributions of SOA tracers to organic carbon (OC) and water-soluble organic carbon (WSOC) were
found to be 0.92% and 1.9%, respectively during the sampling period. Using a tracer-based method, we
estimated the concentrations of secondary organic carbon (SOC) produced from isoprene, α-/β-pinene
and β-caryophyllene as 159 ngC m-3, 35 ngC m-3 and 66.3 ngC m-3, respectively. The contributions ofisoprene, α-/β-pinene and β-caryophyllene to SOC were estimated to be 14.4%.

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P1-03

Turbulence structure measurement in atmospheric surface layers
visualized by a PIV technique
Fumihiro Mori1, Kou Shimoyama2, Tsutomu Watanabe2(1) Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
fumihiro-11@lowtem.hokudai.ac.jp
Particle Image Velocimetry (PIV) is a powerful tool to measure spatial structures of atmosphericturbulence since the method allows us to measure instantaneous velocity in two-dimensional vector field.
However, PIV have been generally used in wind tunnel experiments and rarely adopted for the fieldobservations. In this study, we developed a PIV observation system designed for field experiments
aiming at acquiring velocity vectors in vertical or horizontal sections of up to 30m width.
The PIV system consists of portable equipments; laser, video camera and the tracer seeding devices, inorder to arrange the observing scale to variable conditions of turbulence. Two-dimensional image iscaptured with market production models of digital video camera by AVCHD, MOV and MPEG formats.
Spatial coverage and adequate density of tracer particles for the measurement are optimized using 6 setsof the specially designed seeding discharge ports. They output a tracer particles at similar temperature
with environments and a uniform flowing velocity from an overall lateral width, 2.5m, of the port.
Field experiment of PIV was done over a flat homogeneous grass field. The measurement section was avertical-streamwise cross-section; analysis range and a vector calculation points were 8.35m and 76
points in the horizontal direction and 4.0m and 36 points in the vertical direction, respectively. The
measurement period was 10 minutes with the wind direction that was along the sheet of laser light. To
examine the accuracy of the field PIV, instantaneous velocities and mean statistics obtained from PIV
and a supersonic anemometer set in the measurement section were compared. The PIV’s time series inboth horizontal and vertical wind speed traced well the variation trend obtained by the sonic anemometer.
Although a limitation due to the resolution of images was apparent in the variance of the vertical velocity,that of horizontal velocity was reasonably comparable.
During the analysis period, the characteristic structure that updrafts while convecting in the main flow
direction was generated repeatedly in a short period of time. As a result of the traditional conditional
sampling procedure (Adrian et al. 2000), the tip section swirling and the ejection motion following it
were selectively observed. Thus, even on the ground surface, observed were structures similar to thehairpin vortex that was seen in the wind tunnel and numerical experiments. The structure may contributesignificantly to the transport of momentum in the surface layer. Further analysis using the field PIV
system may enhance our understanding of the surface layer turbulence structures.
Reference:
Adrian RJ, Meinhart CD, Tomkins CD (2000) Vortex organization in the outer region of the turbulent
boundary layer. J Fluid Mech 422:1-54.

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P1-04Ice-ocean albedo feedback effect on recent drastic reduction in
Arctic sea ice coverHaruhiko Kashiwase1,2, Kay I. Ohshima2, Sohey Nihashi3, and Hajo Eicken4(1) National Institute of Polar Research, Tokyo, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(3) Tomakomai National Collage of Technology, Japan(4) International Arctic Research Center, Fairbanks, USA

Associated with the recent global warming, sea ice conditions in the Arctic Ocean has drasticallychanged (e.g. reduction of summer ice extent, decrease of mean ice thickness, and decrease of multiyear ice fraction) particularly in the Pacific Arctic sector beginning in the 2000s. In seasonal ice zones
such as the Antarctic Ocean and Sea of Okhotsk, a positive feedback caused by the albedo contrast
between water and ice surfaces (~0.7 and ~0.07, respectively), termed as “ice-ocean albedo feedback”,
enhances ice melt and partly controls its interannual variability (Nihashi and Cavalieri, 2006). Recently,
this feedback has also received attention in the context of drastic decreases in summer Arctic ice extent.
However, key questions, such as how much of the recent decline and interannual variation in sea ice
extent are explained by the heat input through the open water fraction, or the specific physical processes
at work in triggering and translating the feedback, remain unanswered. This study examines how theice-ocean albedo feedback affects the Arctic sea ice retreat and recent drastic reduction of summer ice
extent, based on analyses using sea ice data from satellite microwave radiometers (e.g. ice concentrationand drift speed) and a simplified ice-ocean coupled model.
First, focusing on the Pacific Arctic sector, we calculated the daily net heat budget over the ice
covered area (defined as ice concentration ≥ 30%) and the volume of ice melt and export. Results ofheat budget analysis indicate that the necessary conditions for the ice-ocean albedo feedback are satisfied
in the study area: (1) net heat budget at the water surface is much larger than at the ice surface even if
the effect of melt ponds is included as their maximum impact, (2) ice retreat is mainly explained by ice
melt, and (3) heat input through the open water fraction corresponds well with the ice melt volume forboth seasonal and interannual variations. Then we compared the ice divergence with the ice melt volume,and found that the divergence on early melt season (from mid-May to early-June) has significant
correlation with the 1-2 months lagged ice melt. This means that a small difference in ice concentrationinduced by the ice motion acts as the trigger of ice-ocean albedo feedback. Also it is remarkable thatthe heat input through the open water fraction, ice melt volume, and early summer divergence has adistinct increasing trend beginning in the 2000s, suggesting that recently this feedback has become
sensitive and thus contributes to the drastic ice reduction in the study area (or the entire Arctic Ocean aswell).
Finally seasonal sea ice retreat and its interannual variability in the Pacific Arctic are examinedwith a simplified ice-upper ocean coupled model in which the heat input through the open water fractionis the only heat source for ice melt (Ohshima and Nihashi, 2005). The model explains that ice motion
and distribution of multi-year ice as key factors of the seasonal/interannual variability of ice retreat
through the ice-ocean albedo feedback.
References:
Nihashi, S., and D. J. Cavalieri (2006), Observational evidence of a hemispheric-wide ice–ocean albedo feedback effect on
Antarctic sea-ice decay, J. Geophys. Res., 111, C12001, doi:10.1029/2005JC003447.
Ohshima, K. I., and S. Nihashi, (2005), A simplified ice–ocean coupled model for the Antarctic ice melt season, J. Phys.
Oceanogr., 35, 188–201, doi:10.1175/JPO-2675.1.

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P1-05Predictability of the Barents Sea ice in early winter:
Remote effects of oceanic and atmospheric thermal conditions
from the North Atlantic
Takuya Nakanowatari1,2, Kazutoshi Sato3, Jun Inoue1,3,4(1) National Institute of Polar Research, Tachikawa, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(3) The Graduate University for Advanced Studies, Tachikawa, Japan(4) Institute of Arctic Climate and Environment Research, JAMSTEC, Yokosuka, JapanThe sea ice variability of the Barents Sea in early winter (December) and its resultant dynamical
atmospheric response is considered to be the triggers of a dynamic atmospheric response with severe
consequences for weather conditions over the Eurasia continent including Japan [e.g., Inoue et al., 2012;
Mori et al. 2014]. In this study, predictability of sea ice concentrations (SICs) in the Barents Sea in early
winter (November−December) is studied using canonical correlation analysis with atmospheric andocean anomalies from the NCEP Climate Forecast System Reanalysis (NCEP-CFSR) data [Saha et al.
2010]. We find that the highest prediction skill for a single-predictor model is obtained from the 13month lead subsurface temperature at 200-m depth (T200) and the in-phase meridional surface wind
(V sfc ). T200 skillfully predicts SIC variability in 35% of the Barents Sea, mainly in the eastern side. The
T200 for negative sea-ice anomalies exhibits warm anomalies in the subsurface ocean temperaturedownstream of the Norwegian Atlantic Slope Current (NwASC) on a decadal timescale. The diagnostic
analysis of NCEP-CFSR data suggests that the subsurface temperature anomaly stored below thethermocline during summer re-emerges in late autumn by atmospheric cooling and affects the sea-ice.
The subsurface temperature anomaly of the NwASC is advected from the North Atlantic subpolar gyreover ∼3 years. V sfc skillfully predicts SIC variability in 32% of the Barents Sea, mainly in the westernside. The V sfc for the negative sea-ice anomalies exhibits southerly wind anomalies. V sfc is related to thelarge-scale atmospheric circulation patterns from the subtropical North Atlantic to the Eurasiancontinent, which is similar to the atmospheric response of the upper troposphere in the linear baroclinic
model driven by the wintertime diabatic heating in the Gulf Stream [Sato et al. 2014]. Our study suggeststhat both atmospheric and oceanic remote effects have a potential impact on the forecasting accuracy of
SIC. These results were published by Journal of Climate [Nakanowatari et al. 2014].
References:
Inoue, J., M. Hori, and K. Takaya (2012), The role of Barents sea ice in the wintertime cyclone track and emergence of a WarmArctic Cold Siberian anomaly, J. Climate, 25, 2561-2568.
Mori, M., M. Watanabe, H. Shiogama, J. Inoue, and M. Kimoto (2014), Robust Arctic sea-ice influence on the frequent
Eurasian cold winters in past decades, Nat. Geosci. 7, 869−873.
Nakanowatari, T., K. Sato, and J. Inoue (2014), Predictability of the Barents Sea ice in early winter: Remote effects of oceanicand atmospheric thermal conditions from the North Atlantic, J. Climate, 27, 8884–8901.
Sato, K., J. Inoue, and M. Watanabe (2014), Influence of the Gulf Stream on the Barents Sea ice retreat and Eurasian coldness
during early winter, Environ. Res. Lett., 9, 084009.

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P1-06

Investigation of ice-ocean interaction on Lutzow-Holm Bay,
East Antarctica, from geographic, ocean data analysis
and modeling
Tatsuru Sato1, Yoshimasa Matsumura1, Alexander D. Fraser1, 2(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Antarctic Climate and Ecosystem Cooperative Research Center, Hobart, Australia

Observations suggest that the Southern Ocean is changing. Warming in this region and the West
Antarctic Ice Sheet melt changes its thermal conditions. In the East Antarctica, land fast ice and sea-ice
area is also increasing (Massom et al., 2013). Ice-ocean interaction studies are important to reveal thesechanges in each region of the Southern Ocean. Here we would like to present an investigation of iceocean interaction on Lutzow-Holm Bay, East Antarctica, from geographic, ocean data analysis andnumerical modeling. This study focuses on this interactions on ice shelves along the Riiser-Larsen
Peninsula and land fast sea-ice region around the bay. In this region, morphology was not well assembled.
First we investigated the topography, the grounding line and the calving front of ice shelves using
observational and satellite based data.
There is a trough which connects abyssal ocean to ice shelf cavities in Riiser-Larsen Peninsulaand Soya coast. The observation based topography is not clear in the west part of this trough due tocoarse observations and ice shelves along the Riiser-Larsen Peninsula. Some of these ice shelf cavity
topographies are estimated using Bedmap2 dataset (Fretwell et al., 2013). Since topography dataset
under these ice shelves is limited, it is preferable to perform observations in this area. Landfast sea-ice
area in this region was detected by MODIS images (Fraser et al., 2012). Although this area changes
seasonally (Ohshima et al., 2000; Fraser et al., 2012), it is nearly constant except for several months insummer and autumn.
The grounding line and islands are detected using the combination of observational data,
Bedmap2 and a digital elevation map based on ERS1 and Icesat satellite. Ice shelf drafts are also
estimated from these surface elevation map. Ice shelf drafts are about 600 m at the grounding area. Since
these ice shelf drafts are not so deep, sub-ice-shelf melting would depends on water and heat transport
though the trough and fast ice. When sub-ice-shelf melting is limited, calving, which would haverelationship between fast ice evolution, would be the main ablation mechanism of ice shelves in thisregion.
References:
Fraser, D. A., R. A. Massom, K. J. Michael, B. K. Galton-Fenzi, and J. L. Lieser., 2012. East Antarctic Landfast Sea Ice
Distribution and Variability, 2000–08. Journal of Climate, 25, 1137–1156.
P. Fretwell., H. D. Pritchard, D. G. Vaughan, J. L. Bamber, N. E. Barrand, R. Bell, C. Bianchi, G. Bingham, D. D. Blankenship,
G. Casassa, G. Catania, D. Callens, H. Conway, A. J. Cook, H. F. J. Corr, D. Damaske, V. Damm, F. Ferraccioli, R. Forsberg,
S. Fujita, Y. Gim, P. Gogineni, J. A. Griggs, R. C. A. Hindmarsh, P. Holmlund, J. W. Holt, R. W. Jacobel, A. Jenkins, W. Jokat,
T. Jordan, E. C. King, J. Kohler, W. Krabill, M. Riger-Kusk, K. A. Langley, G. Leitchenkov, C. Leuschen, B. P. Luyendyk, K.
Matsuoka, J. Mouginot, F. O. Nitsche, Y. Nogi, O. A. Nost, S. V. Popov, E. Rignot, D. M. Rippin, A. Rivera, J. Roberts, N.
Ross, M. J. Siegert, A. M. Smith, D. Steinhage, M. Studinger, B. Sun, B. K.Tinto, B. C. Welch, D. Wilson, D. A. Young, C.
Xiangbin, and A. Zirizzotti, 2013. Bedmap2: improved ice bed, surface and thickness datasets for Antarctica. The Cryosphere,
7(1).
Massom, R., Reid, P., Stammerjohn, S., Raymond, B., Fraser, A., and Ushio, S., 2013. Change and variability in East Antarctic
sea ice seasonality, 1979/80–2009/10. PloS one 8 (5), e64756-e64756.
Ohshima, K. I., Kawamura, T., Takizawa, T., Ushio, S., and Miyakawa, T., 2000. Current variability under landfast sea ice in
Lützow-Holm Bay, Antarctica. Journal of Geophysical Research: Oceans (1978–2012), 105(C7), 17121-17132.

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P2-01

Antarctic ice shelves’ basal melting in glacial and warm climates
Takashi Obase1, Ayako Abe-Ouchi1, Kazuya Kusahara2, Hiroyasu Hasumi1(1) Atmosphere and Ocean Research Institute, the University of Tokyo, Kashiwa, Japan(2) Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania,
Hobart, Australia

Basal melting of the Antarctic ice shelves is an important factor in the retreat of marine Antarctic ice
sheet in the past or future, but little consensus exists on how the rate of basal melting changes against
climatic forcing. Antarctic ocean and basal melting of Antarctic ice shelves under the Last Glacial
Maximum (LGM) and equilibrium CO2 doubling climate are investigated using a circumpolar ocean
model with ice shelf cavity component forced by outputs of a climate model. To focus on the role ofclimatic forcings, identical present-day topography is used in these experiments.

The rate of basal melting increases as the climate is warmed, but change in basal melting in the CO2
doubling climate is much larger than that in the LGM in spite of close magnitude of global radiative
forcing. The model show that difference in basal melting is a result of difference in water mass formationof cold water in the shelf seas, and water mass formation in the Antarctic Coast influences on the
intrusion of warm subsurface water from the Southern Ocean. Active sea ice production in the Antarctic
Coast forms saline and cold shelf water, which keeps basal melting to be inactive under cold climate
and present-day. In contrast, under a warmer climate, basal melting increases by increased ocean
temperature outside the continental shelf break and active intrusion of warm subsurface water toapproach ice shelves.

A parameterization of basal melting for ice sheet model is formulated using observed and modelled
ocean temperature outside the shelf break and the thickness of the ice shelf. The impact of basal melting
on the retreat of West and East Antarctic Ice Sheet will be investigated using a 2-d ice sheet model.
Reference:
Obase, T., Abe-Ouchi, A., Kusahara, K. and Hasumi, H., The responses of Antarctic ice shelves’ basal melting to climatic
forcing and its mechanisms under LGM and CO2 doubling climates, in prep.

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P2-02A simple parameterisation of ice-shelf basal melting for long-term,large-scale simulations of the Antarctic ice sheet
Ralf Greve1, Ben Galton-Fenzi2,3, Rupert Gladstone3,4(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Australian Antarctic Division, Kingston, Tasmania, Australia(3) Antarctic Climate and Ecosystems CRC, Hobart, Tasmania, Australia(4) VAW, Swiss Federal Institute of Technology in Zurich, Switzerland

Ice-shelf basal melting is the largest ablation process of the recent Antarctic ice sheet, and it is very
unevenly distributed (half of the meltwater originates from ten small, warm-cavity Southeast Pacific ice
shelves; Rignot et al., 2013). Therefore, ice-shelf basal melting, and its change with time, plays a crucialrole for the past and future evolution of the Antarctic ice sheet and its contribution to global sea level(Bindschadler et al., 2013). Since integrating coupled ocean and ice sheet models for long time periods
is hard to achieve within a reasonable amount of time using present-day computers, long-term
simulations of the Antarctic ice sheet require that ice-shelf basal melting is parameterised.
Here we describe a simple, physically-based parameterisation that calculates the basal melting of
ice shelves as a function of both the ice-shelf draft (depth of the ice base below mean sea level) and thethermal forcing. The latter is taken as the difference between the ocean temperature at 500 m depth justoutside the ice-shelf calving front (World Ocean Atlas 2009; Locarnini et al., 2010) and the freezing
temperature of sea water at the ice-shelf base. The parameterisation is tuned differently for eight
Antarctic sectors [(1) Western East Antarctica, (2) Amery/Prydz Bay, (3) Sabrina Coast/Aurora
subglacial basin, (4) George V Coast/Wilkes subglacial basin, (5) Ross Sea, (6) Amundsen Sea, (7)Bellingshausen Sea, and (8) Weddell Sea] in order to achieve reasonable agreement with the modern
spatial distribution of ice-shelf basal melting. For each sector, this yields a dimensionless sensitivity
parameter Ω and an exponent α that describes the nonlinearity of the explicit dependence on the iceshelf draft. In addition, we consider an optional dependence on water column thickness in order to reduce
melting to zero very close to the grounding line.
By construction, the parameterisation reproduces total and sectorial melting rates, as well as large
melting rates under deep and small melting rates under shallower parts of the ice shelves, very well.
However, due to different physics, neither locally enhanced melting near calving fronts nor accretion of
frazil ice (that can lead to net basal freezing instead of melting) are described. The parameterisation is
implemented in the Antarctica module of the dynamic/thermodynamic, large-scale ice sheet model
SICOPOLIS (www.sicopolis.net), and we discuss several future climate runs over the next centuries inorder to explore the sensitivity to various forcings.
References:
Bindschadler, R. A., and 27 others. 2013. Ice-sheet model sensitivities to environmental forcing and their use in projecting
future sea level (the SeaRISE project). J. Glaciol. 59 (214), 195-224.
Locarnini, R. A., and 7 others. 2010. World Ocean Atlas 2009, Volume 1: Temperature. S. Levitus, Ed. NOAA Atlas NESDIS
68, U.S. Government Printing Office, Washington, D.C., 184 pp.
Rignot, E., S. Jacobs, J. Mouginot and B. Scheuchl. 2013. Ice-shelf melting around Antarctica. Science, 341 (6143), 266-270.

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P2-03

Towards a GPU-accelerated ice sheet model: design philosophy
and implementation
Hakime Seddik, Ralf Greve
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Recently, numerous models capable of modeling the thermo-dynamics of ice sheets have beendeveloped within the ice sheet modeling community. Their capabilities have been characterized by awide range of features with different numerical methods (finite difference or finite element), different
implementations of the ice flow mechanics (shallow-ice, higher-order, full Stokes) and different
treatments for the basal and coastal areas (basal hydrology, basal sliding, ice shelves). Shallow-ice
models (SICOPOLIS, IcIES, PISM, etc) have been widely used for modeling whole ice sheets(Greenland and Antarctica) due to the relatively low computational cost of the shallow-ice
approximation but higher order (ISSM, AIF) and full Stokes (Elmer/Ice) models have been recently used
to model the Greenland ice sheet.
The advance in processor speed and the decrease in cost for accessing large amount of memoryand storage have undoubtedly been the driving force in the commoditization of models with higher
capabilities, and the popularity of Elmer/Ice (http://elmerice.elmerfem.com) with an active user base isa notable representation of this trend. Elmer/Ice is a full Stokes model built on top of the multi physics
package Elmer (http://www.csc.fi/english/pages/elmer) which provides the full implementation of thecomplex finite element procedure and is fully parallel (mesh partitioning with OpenMPI
communications). Elmer is mainly written in Fortran 90 and targets essentially traditional processors as
the code base was not initially written to run on modern coprocessors (yet adding support for the recently
introduced Xeon Phi, x86-based coprocessors is an ongoing work within the Elmer developers).
Furthermore, a truly modular and object-oriented implementation is required for quick adaptation to fast
evolving capabilities in hardware (Fortran 2003 provides an object-oriented programming model while
not being clean and requiring a tricky refactoring of Elmer code).
In this work, the object-oriented, coprocessor-accelerated finite element code Sainou is
introduced. Sainou is an Elmer fork which is reimplemented in Objective-C and used for experimenting
with ice sheet models running on coprocessors, essentially GPU devices. GPUs are highly parallel
processors that provide opportunities for fine-grained parallelization of the full Stokes problem using
the standard OpenCL language (http://www.khronos.org/opencl/) to access the device. Sainou is built
upon a collection of Objective-C classes that service a modular core class which provides the methods
to solve the finite element problem. Those classes and their implementation form an API (Application
Programming Interface) and are compiled into a Framework, a single package that encapsulates header
files, dynamic shared libraries, shared resources and reference documentation.
The capabilities of this framework will be presented and the possibility to build a simple finite
element application using the framework will be demonstrated. The strategy for parallelizing the finite
element global matrix assembly will also be presented. Sainou uses a greedy coloring algorithm (Dimitri
et al., 2010) to partition the finite element mesh so that elements with the same color but with distinct
nodes are assembled in parallel on the GPU. This algorithm allows for memory access correctness
without the need of expensive atomic or synchronization primitives, but with the added computational
cost that the mesh has to be colored only once. The preliminary GPU implementation is then tested withsimple applications.
Reference:
Dimitri, K., G. Erlebacher, D. Göddeke and D. Michéa. 2010. High-order finite-element seismic wave propagation modelingwith MPI on a large GPU cluster. Journal of Computational Physics, 229 (20), 7692-7714.

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P2-04

Shallow ice core project on south-east dome in Greenland– Drilling report and science trench of the ice core –Yoshinori Iizuka, Sumito Matoba, Kunio Shinbori, Takeshi Saito, Ryoto Furukawa, Ikumi
Oyabu, Moe Kadota, Osamu Seki, Shin Sugiyama1, Atsushi Miyamoto2, Tetsuhide
Yamasaki3, Akira Hori4, Teruo Aoki5, Satoru Yamaguchi6, Koji Fujita7, Ryu Uemura8, Shuji
Fujita, and Hideaki Motoyama9(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Institute for the Advancement of Higher Education, Hokkaido University, Sapporo, Japan(3) Avagnaq, Japan/Greenland(4) Kitami Institute of Technology, Kitami, Japan(5) Meteorological Research Institute, Tsukuba, Japan(6) The National Research Institute for Earth Science and Disaster Prevention, Nagaoka, Japan(7) Nagoya University, Nagoya, Japan(8) University of the Ryukyus, Okinawa, Japan(9) National Institute of Polar Research, Tokyo, Japan

We conducted ice core drilling on the southeastern Greenland Ice Sheet on May 2015 to reconstructconcentrations and compositions of anthropogenic substances after the industrial revolution, and tounderstand physical properties of snow and ice and densification processes at the high accumulation siteof an ice dome. We obtained a 90 m long ice core with an electrical mechanical drill developed by theInstitute of Low Temperature Science (ILTS), Hokkaido University. The ice cores were packed in plasticbags and stored in insulation boxes, and transported at frozen condition to Japan.
The core has unique characteristics as below;– The drilling position is N67°11’, W36°22’, and 3170 m asl.
– One of the domes on Greenlandic ice sheet.
– Very high accumulation region (0.9 m/y in w.e.; 5 times than NEEM; 30 times than DC, DF).
– The depth at 90 m is corresponding to about AD 1950.
– We can chase seasonal variation; in spite of a Greenlandic dome more than 3000 m asl.
– Close-off depth is about 86 m, which is so deeper than the other domes in the ice sheet.
– Less and thin melted layers (–21°C at 20 m in depth).
– Weather is controlled by Icelandic Low, with high winter accumulation.
– Southeast Greenland is highly affected by NAO. It may be detectable decadal scale of climate
fluctuation.
– Southeast Greenland is highly preserved anthropogenic materials from Europe.
– It is seldom papers around the region. There is only papers from DAS2 core.
We have started the science trench in cold rooms for preliminary analyses and ice core cutting. The
preliminary analyses are layer stratigraphy, density of bulk and x-ray methods, photographic
interpretation of visible and near-infrared wavelengths, and dielectric profiling. Also, we cut the ice
sections for chemical analyses. We will present the latest results of these analyses at the meeting.

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P2-05Tide-modulated seismicity in the Bowdoin Glacier calving front,
northwestern Greenland
Evgeny A. Podolskiy1, Shin Sugiyama1, Martin Funk2, Riccardo Genko3,
Masahiro Minowa1, Fabian Walter2, Shun Tsutaki4, 1, Maurizio Ripepe3(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Laboratory of Hydraulics, Hydrology and Glaciology, ETH Zurich, Zurich, Switzerland(3) Dipartimento di Scienze della Terra, Università di Firenze, Florence, Italy(4) Arctic Environment Research Center, National Institute of Polar Research, Tokyo, Japan

A seismic array consisting of four on-ice stations was installed in July 2015 at the central part of the
Bowdoin Glacier calving front, northwestern Greenland, as part of a larger network established for nearsource monitoring of frontal dynamics. Lennartz LE-3D short- and long-period seismometers, poweredby solar panels, were arranged in a triangle-shaped array (with a distance between stations of ~150 m),
located ~200 m from the marginal ice cliff, where icebergs are discharged into the fjord.
Using the classic seismological approach (“Short Term Averaging / Long Term Averaging”
trigger algorithm) we analyzed the temporal variability of microseismic events, which were
continuously recorded over a period of two-weeks. The results show a double-peak diurnal oscillation
in a number of events per hour. A comparison with time-series of tide height data shows that the
maximum seismic activity occurred during falling tides.
The present and previous field work at Bowdoin Glacier (Sugiyama et al., 2015) reveal that ice
flow velocity is also tide-modulated and that the glacier accelerates during falling tides due to reduced
back-pressure. However, this diurnal modulation can be obscured by other factors that affect the rate ofglacier movement, such as high air temperature or rain. The distinct and stable double-peakmicroseismic pattern seems to originate directly from local elastic vertical displacements induced bytides. Presumably, the mechanical cause of such behavior stems from a high-strain-rate extensional
stretching of the glacier surface, which favors the opening of tensional crevasses.
The in situ observations of the present study shed light onto the seemingly chaotic fracture
mechanics of difficult-to-access processes operating at the calving front of the glacier. At this stage ofanalysis, we already found major differences between the present data and previously reported tidemodulated ice-quakes in the Mertz Glacier, east Antarctica (Barroul et al., 2013). For example, the great
sensitivity of the present instruments to high frequencies and their unique near-source location meansthat we were able to observe that seismic activity did not cease at low tidal velocities, contrary to theresults reported for the Mertz Glacier; instead, hundreds of events were recorded per hour during such
periods. Further analyses of microseismic data and the integration of other instruments (e.g., infrasoundarray), would provide greater insights into calving front dynamics.
References:
Barruol, G., E. Cordier, J. Bascou, F. R. Fontaine, B. Legrésy, and L. Lescarmontier, 2013, Tide-induced microseismicity in
the Mertz glacier grounding area, East Antarctica, Geophys. Res. Lett., 40, 5412-5416.
Sugiyama, S., D. Sakakibara, S. Tsutaki, M. Maruyama and T. Sawagaki, 2015. Glacier dynamics near the calving front of
Bowdoin Glacier, northwestern Greenland. J. Glaciol., 61(226), 223-232.

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P2-06

Seasonal variations in the dynamics of Bowdoin Glacier,northwest Greenland
Masahiro Minowa1, 2, Shin Sugiyama1, Takanobu Sawagaki3, Shun Tsutaki1, 4
and Daiki Sakakibara1, 2(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan(3) Faculty of Social Science, Hosei University, Tokyo, Japan(4) Arctic Environment Research Center, National Institute of Polar Research

Submarine melting and ice-mélange weakening are suspected as triggering mechanisms of rapid retreatof tidewater glaciers in the Greenland Ice Sheet (e.g. Straneo et al., 2013). To better understand thesekey processes at the ice-ocean interface, we measured ice-front position and glacier/ice-mélange
movement by processing daily photographs taken by a time-lapse camera operated near the ice-front of
Bowdoin Glacier in the northwest Greenland over two years since 2013. The results showed clear
seasonal variations in the ice-front position with an amplitude of ~600 m, as well as in ice speed at thecenterline of the glacier (Fig 1). During summer, the ice-front position was relatively stable, but retreatedoccasionally by large calving events (Fig 1a Period 1). Most of the calving events occurred near buoyant
plume caused by upwelling of subglacial discharge where a large submarine melt rate is expected. The
glacier began to advance in September approximately when air temperature dropped below 0 °C (Fig.
1a Period 2). The glacier advanced the most in winter when the fjord was jammed by ice-mélange (Fig
1a Period 3). After winter, extended portion of the glacier rapidly disintegrated by a few calving events(Fig 1a Period 4). Such event coincided with initiation of fast ice-mélange movement in front of theglacier (Fig 1b) and temperature increase above 0 °C (Fig 1c). These results indicate both ice-mélange
and submarine melting play roles in seasonal advance and retreat of Bowdoin Glacier. Moreover, theonset of glacier advance (retreat) was coincided with seasonal air temperature change from positive tonegative (negative to positive), implying glacier surface melt water is a controlling process of ice-front
position.
Reference:
Straneo, F. and 15 others, Challenges to understanding the dynamic response of Greenland's marine terminating glaciers tooceanic and atmospheric forcing, Bulletin of the American Meteorological Society, 94(8), 1131–1144, 2013.

Figure 1. Seasonal variations in the ice-front position (a), glacier/ice-mélange speed (b) and air temperature at Qaanaaq airport.

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P2-07

Seasonal changes in ice front position and flow speed of marine
terminating outlet glaciers in northwestern Greenland
Daiki Sakakibara1, 2, Shin Sugiyama1(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan

Mass loss from the Greenland ice sheet has been increasing, resulting in an enhanced contribution to sea
level rise (e.g. Rignot et al., 2011). The mass loss is driven by two processes: increases in surface melting
and ice discharge from marine-terminating outlet glaciers (e.g. Enderlin et al., 2014). Therefore, it isimportant to include evolution of the outlet glaciers in future projection of the sea level rise. To achievethis, influences of atmosphere and the ocean on the glacier dynamics should be better understood. Thus,
it is important to study variations of the outlet glaciers in connection with atmospheric and the ocean
conditions. We analyzed satellite images to measure frontal positions, ice speeds, and conditions of sea
ice / ice mélange in front of the termini of 19 marine terminating outlet glaciers in northwestern
Greenland over the period from 2013 to 2015. The results were utilized to investigate the processes
controlling seasonal changes in the frontal positions and ice speeds in comparison with the atmosphereand the ocean conditions.
Most of studied glaciers showed seasonal changes in ice fronts and ice speeds. Bowdoin, Verhoeff,
Morris Jesup, and Diebitsch Glaciers advanced from spring to early summer and retreated in midsummer. The retreated position continued through the fall. Magnitude of seasonal variations of these
glaciers ranged between 100 and 150 m. Heilprin, Tracy, Farquhar, Melville and Sharp Glaciers often
rapidly retreated following gradual advance. Difference between maximum and minimum terminus
positions of these glaciers is a range from 150 to 400 m. Frontal variations of these glaciers are likely
controlled by formation and breakup of the floating tongue. Frontal retreat of the studied glaciers often
began when sea ice / ice mélange in front of the glacier terminus disappeared. These results suggest thatsea ice / ice mélange in front of terminus suppress the glacier retreat. In general, ice speeds of studied
glaciers increased from spring to mid-summer and then decreased from the mid-summer to the fall.
Difference between minimum and maximum speed of the glaciers is a range between 100 and 500 m a−1.
Because changes in the ice speeds well agreed with change in air temperature, it is suggests that the
speedups of the studied glaciers mainly result from enhanced basal sliding driven by meltwater input tothe bed.
References:
Rignot, E., I. Velicogna, M. R.Van den Broeke, A. Monaghan, and J. Lenaerts. 2011. Acceleration of the contribution of theGreenland and Antarctic ice sheets to sea level rise. Geophys. Res. Lett., L05503.
Enderlin, E. M., I. M. Howat, S. Jeong, M. J. Noh, J. H. van Angelen and M. R. van den Broeke. 2014. An improved mass
budget for the Greenland ice sheet. Geophys. Res. Lett., 41, 866–872.

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P2-08Field observations of surface mass balance, ice velocity and ice
temperature on Qaanaaq ice cap, northwestern Greenland
Shun Tsutaki1,2, Mihiro Maruyama2,3, Shin Sugiyama2, Daiki Sakakibara2,3, Takanobu Sawagaki4(1) Arctic Environment Research Center, National Institute of Polar Research, Tokyo, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(3) Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan(4) Faculty of Social Sciences, Hosei University, Tokyo, Japan

Glaciers and ice caps (GICs) physically separated from the Greenland ice sheet are losing significant
amount of ice mass, and this mass loss plays important contribution to sea level rise. Because the GICs
are located at relatively lower elevations, they are susceptible to recent warming trend in Greenland.
Despite the large mass loss of the GICs revealed by recent satellite data analysis, only a few fieldobservations have been reported in this region. To investigate recent change of Greenland’s GICs by insitu data, we measured surface mass balance, ice velocity and ice temperature on Qaanaaq Ice Cap (QIC)
in northwestern Greenland in the summer 2012–2015. QIC (77°28´N, 69°13´W) is covering an area of
288 km2. We carried out field campaign on Qaanaaq Glacier, an outlet glacier in the southern part of the
QIC. We installed 7 poles along the survey route spanning the glacier terminus to the ice cap summit inorder to measure surface mass balance and ice velocity. We installed 15 m-long cables equipped withthree thermistor censers at three survey points in different elevations (243, 739 and 944 m a.s.l.) on
August 4, 2013 to measure ice temperature at the depth of 3, 8 and 13 m from ice surface.
Surface mass balance near the terminus in 2012–13, 2013–14 and 2014–15 was −1.2, −1.6 and−2.1 m w.e. a−1, respectively. Mass balance at 968 m a.s.l. was 0.56 m w.e. a−1 in 2012–13, 0.30 m w.e.
a−1 in 2013–14 and −0.16 m w.e. a−1 in 2014–15. Because mass balance has large variability from year
to year during the study period, equilibrium line altitude ranged from 900 to 980 m a.s.l. Ice flows fasterin the middle part of the survey route, and the greatest horizontal velocity was observed at 584 m a.s.l..
Ice temperature at the depth of 13 m was −10.7°C near the terminus, while it was −8.0°C at the upper
most site. In summer 2014, we observed about 40 cm thickness of refrozen ice on the ice surface insummer 2012 at the upper most site, while no refreezing occurred near the terminus. This result suggeststhat ice temperature in the upper reaches was influenced by latent heat from refreezing.
References:
Hanna, E., S. H. Mernild, J. Cappelen and K. Steffen. 2012. Recent warming in Greenland in a long-term instrumental (1881–
2012) climatic context: 1. Evaluation of surface air temperature records. Environmental Research Letters, 7 (4), 045404.
Bolch, T., L. S. Sørensen, S. B. Simonsen, N. Mölg, H. Machguth, P. Rastner and F. Paul. 2013. Mass loss of Greenland’s
glaciers and ice caps 2003–2008 revealed from ICESat laser altimetry data. Geophysical Research Letters, 40, 875-881.

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P2-09Elevation change of calving glaciers in northwestern Greenland
analyzed by satellite data
Naoki Katayama1, 2, Shun Tsutaki2, 3, Daiki Sakakibara1, 2, Shin Sugiyama2, Takanobu Sawagaki4(1) Graduate School of Environmental Science, Hokkaido University(2) Institute of Low Temperature Science, Hokkaido University(3) Arctic Environmental Research Center, National Institute of Polar Research(4) Faculty of Social Science, Hosei University

A large number of calving glaciers is distributed along the Greenland coast. After 2005, ice mass loss
has increased in northwestern Greenland, according to Gravity Recovery and Climate Experiment(GRACE). In this region, ice thinning, retreat and ice speed accelerated (e. g. Khan and others, 2010).
These factors are important for ice mass loss, but few data are available for the rate of ice thinning.
We analyzed surface elevation change of the seven calving glaciers near Inglefield Bredning in
northwestern Greenland, using ALOS PRISM data. We processed stereo pair satellite images with adigital map plotting instrument (ERDAS Inc., LPS:Leica Photogrammetry Suite; Planar Systems Inc.,
SD2020) to generate Digital Elevation Models (DEMs). Generated DEMs were compared to measure
ice surface elevation changes during periods of 2007–2010.
The surface elevation of all glaciers decreased and the rate of the elevation change increases
downglacier. Tracy Glacier thinned at the greatest rate of 5–7 ±1.7 m a-1 near the terminus. Surface
lowering were also observed in other glaciers; Farquhar Glacier (3–4 ±1.1 ma-1), Melville glacier (2–4
± 1.1 m a-1), Heilprin glacier (2±1.7 m a-1), Sharp glacier (2±1.0 m a-1), Hart glacier (0–2±1.0 m a-1) andHubbard glacier (0–2±0.9 m a-1).
According to previous study, glaciers in the Melville Bay region in northwestern Greenlandthinned at rates of 2–10 m a-1 over the period 2005–2010 (e. g. Kjær and others, 2012). These rates arecomparable to those observed in this study.
References:
Khan, S. A. and others, 2010. Spread of ice mass loss into northwest Greenland observed by GRACE and GPS. Journal ofGeophysical Research. Letters, 37, L06501.
Kjær, K. H. and others, 2012. Aerial Photographs Reveal Late–20th-Century Dynamic Ice Loss in Northwestern Greenland.
Journal of Science, 337, 569–573.

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P2-10Surface elevation change on Trambau Glacier, Nepal Himalaya,based on remote sensing techniques
Naoya Morimoto1, 2, Shin Sugiyama2, Koji Fujita3(1) Graduate school of Environmental Science, Hokkaido University, Sapporo, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(3) Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan

Himalayan glaciers have been retreating and losing mass since the end of the Little Ice Age (Bolch etal., 2012). The glacier retreat results in formation of glacial lakes and poses potential hazard due toglacial lake outburst flood (GLOF). Tsho Rolpa is one of the largest glacial lakes in the Himalaya formedat the terminus of the Trambau Glacier. Studying changes in Trambau Glacier is important to assess thepotential of the GLOF as well as to project water supply to the region. In this study, we analyze thesurface elevation change on Trambau Glacier from 2000 to 2010 by differencing digital elevation
models (DEMs) generated by remote sensing techniques.
The Trambau Glacier is located in the east Nepal Himalaya (27.9 ° N, 86.5 ° E). It covers an areaof 76.5 km2 and elevation range of 4500–6850 m a.s.l. The glacier is characterized by a thick debris
cover (~0.3 to 0.5 m) and a 400 m high icefall at the middle part of the glacier. In our analysis, surface
elevation change was obtained by differencing two DEMs, one from the Panchromatic Remote-Sensing
Instrument for Stereo Mapping (PRISM) images taken by the Advanced Land Observing Satellite (~2.5m resolution) on December 15 2010 (ALOS DEM), and another one from Shuttle Radar Topography
Mission in 2000 (SRTM DEM) (~90 m resolution). The ALOS DEM was generated by analyzing astereo pair image with a digital workstation equipped with a stereo monitor (SD2020; Planar System,Inc.) and digital photogrammetry software (ERDAS IMAGINE Photogrammetry; ERDAS Inc.). Surface
elevation changes were measured in four separated areas; debris-covered ablation area, debris-freeablation area, equilibrium line altitude (ELA) area, and accumulation area.
The mean elevation change in debris-covered ablation area was −2.6 ± 1.0 m a−1, which wasapproximately three times greater than that in debris-free ablation area (−0.97 ± 0.8 m a−1). This result
indicates the importance of a process, which more effectively controls the surface elevation change thanthe heat insulation by the debris cover. At ELA and accumulation areas, the elevation change rates were−0.55 ± 1.4 m a−1 and 1.1 ± 3.3 m a−1, respectively.
As compared with other debris-covered Himalayan glaciers, the surface elevation change in theablation area was more negative in the Trambau Glacier. A previous study showed that a glacier with alarge proglacial lake loses more ice than other glaciers because of calving caused by wind-driven water
currents (Sakai et al., 2009). Such ice loss in the proglacial lake is a possible driver of the enhanced
thinning on the debris-covered ablation area. We are currently working on accuracy evaluation of the
ALOS DEM with field data, as well as generation of additional DEMs from KH-9 Hexagon images.
Results of these analysis will be presented in the symposium.
This work was supported by JSPS KAKENHI Grant Number 26257202.
References:
Bolch, T., A. Kulkarni, A. Kääb, C. Huggel, F. Paul, J. G. Cogley, H. Frey, J. S. Kargel, K. Fujita, M. Scheel, S. Bajracharya,
M. Stoffel. 2012. The State and Fate of Himalayan Glaciers. Science, 336, 310–314.
Sakai, A, K. Nishimura, T. Kadota and N. Takeuchi. 2009. Onset of calving at supraglacial lakes on debris–covered glaciersof the Napal Himalaya.. Journal of Glaciology, 55 (193), 909–917.

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P2-11

Wetting of quasi-liquid layers on ice surfaces:
Statics and dynamics
Ken-ichiro Murata, Harutoshi Asakawa, Ken Nagashima, Yoshinori Furukawa
and Gen Sazaki
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Studies of surface melting (or premelting) have a long history going back to the pioneering prediction
by Michael Faraday. In 1842, he first hypothesized that thin water layers, now called quasi-liquid layers(QLLs), cover ice crystal surfaces even at a temperature below the melting point. This intriguing
phenomenon has attracted considerable attention due to a link to various natural phenomena in our daily
life: lubrication on ice surfaces, frost heave by ice columns, morphological change of snow crystals andelectrification of thunderclouds [1]. At present, surface melting is known to be not limited only to ice
but is common in a wide range of crystalline solids, such as metals, semiconductors, rare gases, andvarious inorganic, organic and colloidal systems. The significance of surface melting and the resulting
quasi-liquid layer in condensed matter is therefore hard to overestimate.
Here we propose a simple model for surface melting on ice crystals with the aid of the wetting
theory. We show that QLLs, resulting from surface melting, exhibit complex wetting behavior: partial,
pseudo partial, complete wetting and their coexistence, relying on the relationship between the spreading
coefficient of QLLs and van der Waals potentials between ice, water and vapor. We demonstrated thethermodynamic criterion for three types of wetting from the force balance of interfacial tensions and thetangent construction of the interfacial potential. This criterion indicates that the spreading coefficient isof negative sign near the solid-vapor equilibrium, meaning that QLLs are fundamentally the transient(metastable) state formed as a result of Ostwald's step rule, and thus exists only in the non-equilibrium
process from ice to vapor or vice versa. Our model casts a serious doubt on the conventional theory
presupposing the coexistence of QLLs with vapor and ice in equilibrium.
Reference:[1] J. G. Dash, A. W. Rempel and J. S. Wettlaufer, Rev. Mod. Phys. 78 (2006), 695.

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P2-12Liquid layers on ice surfaces induced by hydrochloric gas
Ken Nagashima, Gen Sazaki, Hama Tetsuya, Harutoshi Asakawa, Kenichiro Murata,
Shunichi Nakatsubo, Yoshinori Furukawa
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Introduction
It is important for the atmospheric environment to understand the interaction between ice crystals
in clouds and ambient gases [1]. We directly observed ice crystal surface in the presence of hydrogenchloride gas by laser confocal microscopy combined with differential interference contrast microscopy(LCM-DIM) [2-4].
Experimental
Details of the LCM-DIM and the growth chamber are shown in Sazaki (2010) [2]. Samples of
ice single crystals were grown in the chamber on AgI single crystals. The ambient gas was N 2 (<95%),
HCl (<5%), and H 2 O (0.1~1%) at 1 atm. The sample temperature and ambient water vapor pressure
were independently controlled by using Peltier elements for sample ice and for evaporation source ice,
respectively.
Results
The presence of hydrogen chloride gas induced liquid
droplets on the ice surface. The liquid droplets were estimatedto be hydrochloric acid by dissolution of hydrogen chloride gas
in water. Because the melting point of hydrochloric acid islower than 0°C, the droplets did not exist as quasi-liquid layer
and could stably exist as the solution. Under the condition of
evaporation, the concentration of the droplets gradually
increased. Therefore, the ice crystal continued to dissolve in thedroplets of hydrochloric acid until the melting point of droplets
reached the ambient temperature by the decrease of theconcentration (fig.1). If ice crystals in clouds also have thehydrochloric acid droplets, there is a possibility to cause
various chemical reactions as difficult gas-gas reactions.

0 sec.
solid

20 µm

liquid10 s

20 s

References
1) V. Faye McNeill et al., PNAS 103, 9422-9427 (2006).
2) G. Sazaki et al., PNAS 107, 19702-19707 (2010).

30 s3) G. Sazaki et al., PNAS 109, 1052-1055 (2012).
4) H. Asakawa et al., Crystal Growth & Design 14, 3210-3220 (2014).

Figure 1. LCM-DIM images of liquid layers on an ice basal face at–0.5°C. The liquid droplets intensely moved around on the ice surface and the droplets sometimes coalesced each other.
Although the height of the droplets were emphasized by LCM-DIM, the actual heights were smaller than 500 nm, which was
calculated by the contact angle (a few degree).

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P3-01

Evolution of photosystems in green algae through ice ages
Atsushi Takabayashi
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Photosynthetic organisms have various chlorophyll and carotenoid pigments to form their own
photosystems, which help them adapt to various environments. Chlorophyll b is used primarily in green
plants, while chlorophyll a is used in all the oxygenic photosynthetic organisms. The absorption
spectrum of chlorophyll b is slightly different from chlorophyll a, suggesting that chlorophyll b in green
plants enables them to absorb broader spectrum of solar energy efficiently. In addition, chlorophyll b is
expected to be more suitable to absorb available light spectrum in clear sea water than that of chlorophylla. However, the evolutionary importance of chlorophyll b acquisition has not been fully understood.
Green plants are divided into two groups; chlorophytes and streptophytes. Chlorophytes includes
prasinophytes and core chlorophytes. Prasinophytes are mainly lived in marine environments, whereas
core chlorophytes are lived in freshwater/marine environments. Core chlorophytes are believed to be
evolved from prasinophytes. Stroptophytes including some freshwater green algae and land plants andmembers of streptophytes had evolved to land plants. Common ancestors of chlorophytes andstreptophytes have not been found. However, streptophytes was thought to be evolved in freshwater
environments, while chlorophytes was thought to be evolved in marine environments. It should be notedthat both groups of green algae have survived through ice ages, especially through the Sturtian andMarinoan glaciations. Earth in these periods are thought to be completely covered with ice, whichreferred to as “Snowball Earth”. How the eukaryotic algae including green algae have survived throughthese periods have been under debate.
Here, we cultured and collected various green algae and compared their photosystems.
Chlorophyll b was highly accumulated in the photosystems of prasinophyte algae as reported previously.
Given the marine habitats of prasinophytes, this is consistent with the fact that chlorophyll b is moresuitable for light harvesting in clear seawater than chlorophyll a. Light-harvesting systems in green algae
was classified into two systems; core antenna and peripheral LHC (light-harvesting complex) antenna.
The core antennae of photosystems were thought to be highly conserved among green plants andconsisted of chlorophyll a, while LHC antennae were quite divergent and consisted of both chlorophylla and chlorophyll b. Then, we separated core antennae and LHC antennae and analyzed their pigment
contents.
Surprisingly, prasinophytes accumulate much chlorophyll b in both core antennae and LHC
antennae, although streptophytes and freshwater chlorophytes accumulate chlorophyll b only in LHC
antennae. These data demonstrated that prasinophytes have developed their unique photosystems toadapt marine habitats, where light intensity is very low and available light spectrum is quite limited. On
the other hand, streptophytes have developed their photosystems to adapt to freshwater environments,
where light irradiance is strong and fluctuating. The characteristics of the streptophyte photosystems
should have a great advantage in colonization of terrestrial habitats. Based on the data, we hypothesizedthat the photosystems of prasinophytes have an advantage in surviving under thick covering of ices,where the available light intensity was quite limited. In contrast, the photosystems of streptophytes havean advantageous in surviving on ice, where the tolerance for strong and fluctuating light illumination isrequired.

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P3-02Intracellular “energy bento-box”: Flow cytometry as a method tosort microalgae and bacteria based on cell energy reserves
Mia Terashima1, Elizabeth S. Freeman2,a, Robert E. Jinkerson2,a, Martin C. Jonikas2,a,Souichiro Kato3,4,b, Yoichi Kamagata3,4,b(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Department of Plant Biology, Carnegie Institution for Science, Stanford, USA(3) Bioproduction Research Institute, AIST, Sapporo, Japan(4) Graduate School of Agriculture, Hokkaido University, Sapporo Japan(a) Co-authors for the first project; (b) Co-authors for the second project
Many microorganisms accumulate high-energy compounds such as triacylglycerols (TAG) andpolyphosphate (polyP) in intracellular granules. These compounds provide energy reserves for the cellto survive suboptimal conditions. Additionally, recent findings have suggested that these high-energy
granules are not simply for energy storage, but have important cellular roles involved in protein folding,gene expression and signaling, among others (Gao 2015, Gray 2015). In addition to understanding thefunctional significance of these energy reserves, identifying mutants or strains with increased
accumulation of TAG or polyP is of biotechnological interest due to our current dependence on nonrenewable energy and phosphate sources (i.e. fossil fuel and phosphate mining).
Here, I will present the use of flow cytometry as a high-throughput screen to detect and enrichfor cells hyper-accumulating TAG or polyP by using fluorescence dyes that have a specific emission
profile for TAG or polyP. Both methods employ sorting of living cells, which allow for the recovery ofcells after the screen. I will first talk about the method we have developed for isolating mutants withincreased lipid accumulation in model alga Chlamydomonas reinhardtii (Terashima 2015). The method
was optimized using a mutant strain of C. reinhardtii known to accumulate high levels of TAG. Thiswas followed by screening a pool of ~ 60,000 mutants and enriching for cells with increased lipid
fluorescence. Follow-up analysis of 24 isolated mutants revealed that 50 % of the mutants have a
reproducible high lipid phenotype.
Secondly, I will present ongoing work on wastewater bacterial community screening for polyP
hyper-accumulating strains. Wastewater contains a diversity of microbial organisms, but the growth
conditions stimulate different bacteria to dominate a given community. We tested growing thecommunity by varying carbon sources and time periods and found that dominant polyP accumulating
species varied among the growth conditions. Initial findings suggest that bacterial species stemmingfrom the phylum Firmicutes and alphaproteobacteria were among the polyP hyper-accumulators andmay have a larger role in phosphate removal from wastewater than previously expected.
In the final section, I will discuss applying this method to analyze microalgae and bacteria foundon alpine snowfields. Such psychrophilic organisms face extreme changes in temperature, light, waterand nutrient availabilities and have developed mechanisms for long-term survival. These coping
strategies include accumulating protective pigments such as astaxanthin and intracellular high-energy
granules, which are parameters that can easily and rapidly be monitored using methods established inthese studies.
References:Gao, Q. and Goodman, J.M. The lipid droplet-a well-connected organelle. Front Cell Dev Biol, 3:49.
Gray, M.J. and Jakob, U. Oxidative stress protection by polyphosphate — new roles for an old player.
Terashima, M., Freeman, E.S., Jinkerson, R.E. and Jonikas, M.C. A fluorescence-activated cell sorting-based strategy for rapid
isolation of high-lipid Chlamydomonas mutants. The Plant Journal, 81:147-159.

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P3-03Characterization of a novel sulfate-reducing bacterium possessing
desulfoviridin and vibroid morphology
Miho Watanabe, Hisaya Kojima, Manabu Fukui
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Background: The order Desulfovibrionales is organized in four families; Desulfovibrionaceae,
Desulfonatronumaceae, Desulfohalobiaceae and Desulfomicrobiaceae. The genus Desulfomicrobium
is a sole member of family Desulfomicrobiaceae at the time of writing. The genus have beencharacterized as rod- or ellipsoidal-shaped morphology and absence of desulfoviridin. In this study, anovel strain Pf12BT related to Desulfomicrobium species was isolated in pure culture.
Objective: The aim of our study is characterization of the strain Pf12BT.
Methods: Strain Pf12BT was obtained from an enrichment culture established under sulfatereducing conditions at 45°C with an inoculum of sediment from a brackish meromictic lake. Isolationof the strain was carried out by repeated agar shake dilution method.
Results: Cells were vibroid, and motile. The closest relative of the strain was Desulfomicrobium
baculatum with 16S rRNA gene sequence similarity of 91%. Phylogenetic analysis based on the 16S
rRNA gene sequence revealed that the strain Pf12BT belonged to the family Desulfomicrobiaceae, inthe order Desulfovibrionales, Deltaproteobacteria. This result was also supported by the phylogenetic
analysis based on DsrA amino acid sequence. Sulfate, sulfite, thiosulfate were used for electron
acceptors. Formate and fumarate were used for substrate in the presence of sulfate. Yeast extract
enhanced growth of the strain. The isolate grew at temperatures between 13-50°C with an optimum
temperature range of 42-45°C. The strain was desulfoviridin positive. Major cellular fatty acids of theisolate were C 16:0 and C 18:0 .
Conclusion: It was suggested that the strain Pf12BT is a representative of novel species of novel
genus within the family Desulfomicrobiaceae.
Reference:
Watanabe, M., Kojima, H. and Fukui, M. 2015. Desulfoplanes formicivorans gen. nov., sp. nov., a novel sulfate-reducing
bacterium isolated from a brackish meromictic lake, and emended description of the family Desulfomicrobiaceae. International
Journal of Systematic and Evolutionary Microbiology 65: 1902-1907.

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P3-04

Diversity of sulfate-reducing and sulfur-oxidizing organisms in
sediments of Antarctic lakes
Tomohiro Watanabe1, Hisaya Kojima1, Yoshinori Takano2, Manabu Fukui1(1) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(2) Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology

Sulfur is essential for all organisms as major components of cell materials. There are also a variety ofabundant inorganic sulfur compounds in the biosphere, and prokaryotic respiratory processes dependingon these chemical species are major driving force of sulfur cycle in ecosystems. In the sulfur cycle,
reductive processes are mainly mediated by sulfate-reducing prokaryotes (SRP). SRP are capable ofdissimilatory sulfate reduction coupled with oxidation of organic matter, and this reaction is thought tocontribute largely to anaerobic mineralization in aquatic sediments. Activity of SRP results in generationof sulfide, which supports growth of sulfur-oxidizing prokaryotes (SOP). Both SRP and SOP arepolyphyletic, and their diversities in natural environments are often investigated with analyses offunctional genes that encode key enzymes for dissimilatory sulfate reduction or sulfur oxidation. Oneof such genes, aprA encoding adenosine phosphosulfate reductase is involved in both sulfate reduction
and sulfur oxidation. In the present study, diversity of microorganisms involved in sulfur cycle insediments of Antarctic lakes was investigated by analyzing aprA genes. Sediment samples were obtained
from lakes located in coastal area around Lutzow-Holm Bay. From the genomic DNA directly extracted
from the samples, fragments of aprA genes were amplified using a primer pair designed for concomitantdetection of SRP and SOP. From the resulting PCR products, clone libraries were constructed forsequencing and phylogenetic analysis. Both SRP and SOP were detected, and their community
structures differed among the lakes. Some of them were closely related to known SRP or SOP, but others
had no cultivated close relatives. Despite diversity of detected organisms, lineage specific for Antarctic
lakes was not found. A lineage predominant in one of the lakes was also dominant in a temperatemesotrophic lake, but its physiological characteristics could not be inferred since it only distantly related
to known organisms.

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P4-01

Okhotsk study and connection to the Arctic– Sea ice, environment and life –Hiroyuki Enomoto1,2, Nuerasimuguli Alimasi1,3 and Kazutaka Tateyama3(1) National Institute of Polar Research, Tokyo, Japan(2) The Graduate University for Advanced Studies, Tokyo, Japan(3) Kitami Institute of Technology, Kitami, Hokkaido, Japan

Sea ice and environmental researches have been implemented in the long time. The understanding ofsea ice in the climate, environment, industries and societies have been improved by the long-term effort
of many researchers in the last many decades.
The Arctic summer sea ice coverage has been declining significantly. The winter sea ice coveragein the Northern Hemisphere varies due to decrease of sea ice area in the sub-Arctic seas. Sea of Okhotsk,
Barents Sea, Greenland Sea and Baffin Bay are driving the winter sea ice variabilities in the Northern
Hemisphere.
In the case of sea ice variation in the Sea of Okhotsk, long-term decreasing trend is recorded, andthere are also decadal fluctuations. In the variation of ice-covered seas, we may be able to compare
Arctic condition and sub-Arctic conditions. There are many common concerns and common problems.
Regarding industries, increasing opportunity of navigation in the less ice conditions, maritime disasterprevention and search and rescue (SAR) are important issues.
After Shiretoko Peninsular region became the World Natural Heritage in 2005, we experienced
oil spill damage nearing coast. It was difficult to detect its happening, origin and causes as due to sea
ice coverage. Those case, if happens in the Arctic, their difficulties will be much severe.
With recent developments of Japanese Arctic studies, we have strengthened connection among
Arctic researchers and also local communities in many countries. Okhotsk study can be a pilot study of
discussion on sea ice and life relationships, new research technology, long-term monitoring, andutilizing of traditional knowledge and local experimental activities.

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P4-02

Reconstruction of paleo-environmental changes in the northern
North Pacific region from an alpine ice core
Akane Tsushima1, Sumito Matoba2, Takayuki Shiraiwa2(1) National Institute of Polar Research(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, JapanA 180.17-m ice core was drilled at Aurora Peak in the central part of the Alaska Range, Alaska, in 2008
to allow reconstruction of centennial-scale climate change in the northern North Pacific. The 10-mdepth temperature in the borehole was –2 °C, which corresponded to annual mean air temperature at thedrilling site. In this ice core, there were many melt-refrozen layers due to high temperature and/or strong
insolation during summer seasons. We analyzed stable hydrogen isotopes (δD) and chemical species in
the ice core. The ice core age was determined by annual counts of δD and seasonal cycles of sodium
ions, and we used reference horizons of tritium peaks in 1963 and 1964 and 8 major volcanic eruptions
as age controls. Here, we show that the chronology of the Aurora Peak ice core from 180 m to the top
corresponds to the period from 1666 to the summer season of 2007, with a dating error of ±3 years. This
interval has been divided into three phases; that is, Warm-Wet, Warm-Dry, and Cold-Wet, based on
temporal variation of δD and annual accumulation rate.
We found that the increasing period of precipitation amounts were shown after 1850 and before
1760. Before 1760, δD values are low and d-excess values are high, therefore we considered that due toweakened and/or westerly AL, fraction of water vapor from western side increased, as a result,
precipitation increased. After 1850, δD values are high and d-excess values are Low, therefore we
considered that due to strengthened and/or easterly AL, fraction of water vapor from southern sideincreased, as a result, precipitation increased. Our results suggest that the fraction of water vapor fromwestern side become an important factor for Alaskan environmental changes.
Reference:
Tshusima, A., S. Matoba, T. Shiraiwa, S. Okamoto, H. Sasaki, D. J. Solie and K. Yoshikawa. 2015. Reconstructionof recent climate change in Alaska from the Aurora Peak ice core, central Alaska, Clim. Past, 11, 217-226,
doi:10.5149/cp-11-217-2015.

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P4-03On the structure and dynamics of the Soya Warm Current
from the viewpoint of buoyancy arrest
Tatsuro Karaki1, Humio Mitsudera2(1) Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

This study presents an investigation of the dynamics of the Soya Warm Current along the Hokkaido
coast in the Sea of Okhotsk. The major goal is to develop simple mathematical model to describe
dynamical feature of this geophysical flow, especially the formation mechanism of a jet and a density
front. The model is formulated from the viewpoint of buoyancy arrest (Brink and Lentz 2010) andtheoretical results will be compared to simple numerical ocean model, namely the Princeton Ocean
Model (POM). A steady flow over a constant sloping bottom in a stratified ocean is treated in eachmodel.
Buoyancy arrest is a dynamical steady state of ocean current influenced by the bottom boundary
layer. In general, the force of friction between ocean current and bottom topography can lead to a haltof the current system. However, the frictional effect could be prevented by the presence of stratificationand sloping bottom. In such a care the bottom boundary layer can produce buoyancy (i.e., density front)
and introduce vertical shears in the current that, in turn, can reduce the bottom stress. Reduced bottom
stress then leads to weaker deceleration of the ocean current and possibly a situation in which bottom
stress vanishes and the deceleration of the flow stops entirely. This steady state is known as buoyancy
arrest.
According to buoyancy arrest, we can focus on the following three points about the formation
mechanism of the jet and the density front of the Soya Warm Current. The first is a seasonal thermocline
in the Sea of Okhotsk. The second is a continental slope along the northeastern coast of Hokkaido. The
third is a coastal inflow whose volume transport is about 1 Sv (Fukamachi et al., 2010) from the Soyastrait.
To investigate the relationship between the Soya Warm Current and three points discussed above,
we conducted numerical experiments using a primitive equation ocean model. The model is configured
in a stratified straight channel with a coastal slope and reproduces the jet structure of the Soya Warm
Current. Analysis of the model also shows the situation in which bottom stress vanishes. Because weare struggling to develop theoretical model, we will show the result in this symposium.
Reference:
Brink, K. H., and S. J. Lentz, 2010: Buoyancy arrest and bottom Ekman transport. Part 1: Steady Flow. J. Phys. Oceanogr., 40,
621-635- 65 -

P4-04

Interactions of internal waves and sub-mesoscale vortex
Kaoru Ito, Tomohiro Nakamura
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Mixing of sea water is important for water mass formation and as a drive motor of the global thermohaline circulation. Mixing mechanism have been argued in the context of breaking of the internal waves.
Main source of the wave energy is tidal flow over bottom topography (Polzin, 1997). Recent studies
uncovered that interaction between eddies and internal waves plays important roles in mixing and theformation of local internal wave spectra. The interaction has attracted attention, and remarkable theories,
say, wave capture (Buhler and McIntyre, 2005) were achieved in the parameter range of weak mesoscaleeddies with relatively short internal waves, which allows a WKB like approach.
However, the interaction outside of the above parameter range are not well known; in particular,
universally located sub-mesoscale vortices with tide-induced internal waves of various wavelengths.
For example, around Kuril Islands, there are many submeso-scale vortices with various spatial scales
and strengths (Nakamura et al., 2012). Internal waves with various wavelengths are excited concurrently(Nakamura and Awaji, 2004). Therefore waves should frequently collide with these vortices. In such asituation, incident wavelength is sometimes comparable to spatial scale of a vortex. This requires a
nonWKB like approach. Interactions in such a range of parameter have not been considered in previous
studies.
Here, we investigated the interaction between a vortex and incident internal waves in a wideparameter range, with using theoretical analysis and a numerical model. We started with theoreticalanalysis in scattering of monochromatic internal waves by a single vortex. We obtained scattered wave
solutions for azimuthal modes, whose sum gives the total scattered wave field. The analysis revealed anondimensional parameter useful for classifying the interaction dynamics. This parameter represents a
product of ratios of length and nonlinearity scales.
We then performed numerical experiments with a three-dimensional nonhydrostatic model in awide range of the parameter. In almost linear range, waves are scattered and form contrast of energy
flux. Besides, in nonlinear region, waves are trapped into the vortex and their wavenumber become high,leading to wave breaking. This indicates that mixing is induced by the interaction of internal waves anda sub-mesoscale vortex.
References:
K.L. Polzin, J. M. Toole, J. R. Ledwell, R. W. Schmitt. 1997. Spatial Variability of Turbulent Mixing in the Abyssal Ocean.
Science, 276 (5309), 93-96.
O. Buhler, M. E. McIntyre. 2005. Wave capture and wave-vortex duality. Journal of Fluid Mechanics, 534, 67-95.
T. Nakamura, J. P. Matthews, T. Awaji, H. Mitsudera. 2012. Submesoscale eddies near the Kuril Straits: Asymmetric generationof clockwise and counterclockwise eddies by barotropic tidal flow. Journal of Geographical Research, 117, C12014.
T. Nakamura, T. Awaji, 2004. Tidally induced diapycnal mixing in the Kuril Straits and its role in water transformation andtransport: A three-dimensional nongydrostatic model experiment. Journal of Geophysical Research, 109, C09S07.

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P4-05

A mechanism of ice-band pattern formation caused by resonantinteraction between sea ice and internal waves
Ryu Saiki1, Humio Mitsudera2, Ayumi Manome3, Noriaki Kimura4,
Jinro Ukita5, Takenobu Toyota2, and Tomohiro Nakamura2(1) Graduate School of Environmental Science Hokkaido University, Sapporo, Japan(2) Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan(3) University of Michigan, Ann Arbor, MI(4) Graduate School of Frontier Science Tokyo University, Kashiwa, Japan(5) Faculty of Science Niigata University, Niigata, JapanIce bands are often observed over marginal ice zones (MIZ) in polar seas. A typical ice band pattern has
a regular spacing of about 10 km and extends over 100 km in marginal ice zone. Further, the long axisof an ice band lies to the left (right) with respect to the wind direction in the Northern (Southern)
Hemisphere. Here we show that the resonance between ice-band pattern propagation and internal inertiagravity waves below the sea ice well explains the ice-band pattern formation. Internal waves are
generated by the difference between the stress on the open water and the stress on ice-covered water, as
well as the difference in the angle between these stresses. This in turn reinforces to form ice band patternwith a regular band spacing. Specifically, we have found that:
1: A band spacing on the order of 10 km is selected for by the resonance condition in which theice-band pattern propagation speed coincides with the phase speed of internal inertia-gravity waves.
2: The ice bands tend to develop favorably when the wind direction and the band-propagation
direction are nearly parallel. The velocity acceleration caused by the periodic differential stressassociated with the ice bands, driven by the wind parallel to the band propagation direction, is important.
The wind direction may turn to the left (right) slightly in the Northern (Southern) Hemisphere as a resultof the Coriolis effects.
We qualitatively confirmed the first conclusion by investigating whether the band spacing fromsatellite images (e.g. AVHRR, MODIS) are coincide with the theoretical band spacing. As the result,
we found that this band spacing in the satellite images are able to represent as the consistent scales in
the hydrostatic condition. Further, we use a numerical model and the satellite images then we discuss
about ice-band pattern formation in the continuous stratification.
References:
Fujisaki, A., and L. Y. Oey (2011), Formation of ice bands by winds, J. Geophys Res, 116, C10015.
Ishida K, and K. I. Ohshima (2009), Ice-band characteristics of the Antarctic seasonal ice zone observed using MOS MESSR
images, Atmos-Ocean, 47(3), 169-183, doi:10.3137/OC300.2009.
Muench RD, LeBlond PH, and Hachmeister LE (1983), On some possible interactions between internal waves and sea ice inthe marginal ice zone, J. Geophys. Res., 88(C5), 2819-2826.

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P5-01

Technical Support in ILTS, 2015
Toru Takatsuka, Shunichi Nakatsubo, Takeshi Chigai, Shoichi Mori, Kazuya Ono, Yukako
Kato, Kazuyuki Fujita, Fumiaki Saito, Kunio Sinbori, Masayuki Ikeda, and Naoki Watanabe
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Technical supports in various research fields by the Technical Division of the Institute of Low
Temperature Science, Hokkaido University, are introduced. Technical staffs in the Division support
equipment developments, field observations, laboratory experiments, data analyses, and biological andchemical analyses in various fields covering physics, biology, chemistry, electronic engineering andinformation sciences. This division technically contributes to several ILTS research projects. Some
members participate in expeditions to Arctic, Antarctic, and Pan-Okhotsk regions, successfully carryingout the technical supports. The Technical Division is composed of three shops; Technical Development
Shop, Advanced Technical Support Shop, and Facility Maintenance Shop. The Technical Development
Shop is responsible for design and production of experimental and observational equipment. The
Advanced Technical Support Shop is responsible for design and production of electric instruments andinformation technology, supports of physical and biochemical analyses, and resolving networking
troubles. The Facility Maintenance Shop maintains the low temperature rooms and air-conditioning.
The followings are our outstanding technical developments and contributions in recent years:− Developments for zero-gravity experiments of ice crystal growth in the Japanese Experiment
Module KIBO of the International Space Station.
− Technical support for the oceanic observations in Polar Regions.
− Development of the new astronomical camera system at sub millimeter wavelengths mounted on
the Atacama Desert of Chile.
− Development of over 350 polyvinyl chloride chambers.
− Created automatic image disclosure system using DSLR camera in Monbetsu City.
− Analysis of photosynthesis under changing environments.
− Construction of weather station system in Moshiri, Horokanai Town.

− Support for International Antarctic Institute (IAI) curriculum.
One of the members teaches industrial techniques in Bolivia as JICA (Japan International Cooperation
Agency) Training and Dialogue Program member. Every year, we introduce our works by technicalreports and conference in ILTS. In the symposium, we will show our prominent works in details.

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Local Organizing Committee of the
ILTS International Symposium on Low Temperature Science
Ralf Greve (ILTS)
Gen Sazaki (ILTS)
Tsutomu Watanabe (ILTS)
Toshihiko Hara (ILTS)
Humio Mitsudera (ILTS)
Hidetoshi Watanabe (ILTS)
Takeshi Chigai (ILTS)
Kazuya Ono (ILTS)
symposium@lowtem.hokudai.ac.jp
http://www.lowtem.hokudai.ac.jp/