Annual Report

Hydrospheric Atmospheric Research Center(HyARC)
Nagoya University

2006

drospheric tmosphericesearch enter(HyARC)

2006
NAGOYA
UNIVERSITY

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Contents
Foreword

2

Staff and Organization

3

Research Programme

5

Progress Reports
Projects
Division of Regional – Scale Water Cycle Processes
Laboratory of Meteorology
Laboratory for Climate System StudyLaboratory for Cloud and Precipitation Climatology

Division of Global – Scale Water Cycle Variations
Laboratory of Satellite Meteorology
Laboratory of Eco-Hydrometeorology
Laboratory of Ocean Climate Biology
Laboratory of Bio-Physical Oceanography

List of Publications

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9
12
12
18
22
24
24
26
28
35
37

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Foreword
Six years have passed since the Hydrospheric Atmospheric Research Center(HyARC) at Nagoya University was established to promote research on the
global water cycle. The global water cycle is one of the primary components ofthe Earth system, and its research requires strong and extensive collaboration
among the science and application communities. HyARC functions as an interuniversity collaborative system, which may be unique in the world. During thelast six years, the research style of HyARC has become definite, and specificprojects/activities have been initiated and continued. The projects/activities
include the operation of the International Project Office of the GEWEX Asian
Monsoon Experiment (GAME), a sub-project under GEWEX, led by Prof. T.
Yasunari at HyARC, and the promotion of its follow-on projects. There are 3
ongoing major projects supported with the Grants-in-aid for Scientific
Research. Two projects are being conducted with the support of the Core
Research for Evolutional Science and Technology (CREST) of the Japan
Science and Technology Corporation (JST). HyARC has also collaborated withinstitutions such as the Research Institute of Humanity and Nature (RIHN) andthe National Institute of Information and Communication Technology (NICT),and has its own collaborative activities. We have selected a few center research
projects to be funded from the HyARC budget. Although funds are limited, theprojects are selected based on the feasibility, necessity, and collaboration
requirements. We have four center research projects and seven workshops inthis fiscal year.
Although the number of permanent staff at HyARC is only 11 (4 professors,
4 associated professors, and 3 assistant professors), many post-doctoral candi­dates are involved in active research at HyARC. In addition, we have accepted
graduate students in the Department of Environmental Studies. As a part ofcontributing to the UNESCO International Hydrology Programme (IHP), we
have conducted an IHP training course, which is funded by the Japan Trust
every Japanese fiscal year. This year, the theme of the IHP training course was“Oceanography Basics.”
Nagoya University has undergone a major change toward a flexible manage­
ment system with an emphasis on accountability. At the same time, research
publications and other outreach programs are being encouraged.
Uyeda Hiroshi
Director
Hydrospheric Atmospheric Research Center

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Staff and Organization
Division of Regional-Scale Water Cycle Processes

Research Division

Professor
Assoc. Prof.

UYEDA Hiroshi
YASUNARI Tetsuzo
TSUBOKI Kazuhisa
MASUNAGA Hirohiko

Assist. Prof.

SHINODA Taro
FUJINAMI Hatsuki

Division of Global-Scale Water Cycle Variations

Board ofCouncilors

Professor
Assoc. Prof.

NAKAMURA Kenji
SAINO Toshiro
HIYAMA Tetsuya
MORIMOTO Akihiko

Assist. Prof.

MINO Yoshihisa

Director
Common Section
Advisory
Board

Administrative Office001.HyARC2006-E.indd 3

Technical
OfficeYAMAMOTO Mineko

Secretary
OfficeMIZUNO Tsuyako

Head

MINDA Haruya(Technical Center)

YAMAMOTO Akihiro

GeneralAffairs

YOKOI Masao
KAMAZAWA Kaori

Account
Affairs

FUJIMOTO Masaki
HASEGAWA Kiyoko
NARITA Nobuchika
NOGUCHI Hiroyuki

Student
Affairs

ITO Kanako
TSURU Hironori
YAMAMOTO Chie08.2.1 1:20:02 PMAdministration
Board of Councilors
UYEDA Hiroshi: Director, Prof., Hydrospheric Atmospheric Research Center
YASUNARI Tetsuzo: Prof., Hydrospheric Atmospheric Research Center
NAKAMURA Kenji: Prof., Hydrospheric Atmospheric Research Center
SAINO Toshiro: Prof., Hydrospheric Atmospheric Research Center
UEMURA Daisuke: Prof., Graduate School of Science
HARAGUCHI Hiroki: Prof., Graduate School of Engineering
HATTORI Shigeaki: Prof., Graduate School of Bioagricultural Sciences
Kanzawa Hiroshi: Prof., Graduate School of Enviromentral Studies
FUJII Ryoichi: Prof., Solar-Terrestrial Environment Laboratory

Advisory Board
lMembers from Nagoya Unisversity
UYEDA Hiroshi: Director, Prof., Hydrospheric Atmosphric Research Center
YASUNARI Tetsuzo: Prof., Hydrospheric Atmospheric Research Center
NAKAMURA Kenji: Prof., Hydrospheric Atmosphric Research Center
SAINO Toshiro: Prof., Hydrospheric Atmosphric Research Center
TSUBOKI Kazuhisa: Assoc. Prof., Hydrospheric Atmosphric Research Center
MASUNAGA Hirohiko: Assoc. Prof., Hydrospheric Atmosphric Research Center
HIYAMA Tetsuya: Assoc. Prof., Hydrospheric Atmosphric Research Center
MORIMOTO Akihiko: Assoc. Prof., Hydrospheric Atmosphric Research Center
TSUJIMOTO Tetsuro: Prof., Graduate School of Engineering
OHTA Takeshi: Prof., Graduate School of Bioagricultural Sciences
AGETA Yutaka: Prof., Graduate School of Environment Studies
MATSUMI Yutaka: Prof., Solar-Terrestrial Environment Laboratory
lMembers outside Nagoya University
FUJIYOSHI Yasushi: Prof., Institute of Low Temparature Science, Hokkaido University
HANAWA Kimio: Prof., Graduate School of Science, Tohoku University
SUMI Akimasa: Prof., Center for Climate System Research, The University of Tokyo
FUKUSHIMA Yoshihiro: Prof., Research Intutite for Humanity and Nature
YAMANAKA Manabu: Senior Scientist, Institute of Observational Research for Global Change,
Japan Agency for Marine-Earth Science and Technology

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08.2.1 1:20:03 PMResearch Programme
Diurnal processes of convection/precipitation systems in the climate
systemDiurnal variation in convection and precipitation is a prominent meteorological feature,
particularly in the tropics/subtropics and monsoon regions. Energy, water and momentum
exchanges through the diurnal cycle between the earth surface, atmospheric boundary
layer and free atmosphere play a crucial role in the global climate system. Recently, highresolution satellite (e.g., MTSAT, TRMM) data in time-space become available to use forstudies on the diurnal cycle. However, climate models (i.e. GCM) can still not reproduce a
realistic diurnal cycle in convection/precipitation, inducing systematic errors in the models.
This research plan aims to clarify regionality and seasonality of diurnal processes basedon TRMM, other remote sensing data and in-situ observational data from raingauge
stations. Cloud resolving models (e.g. CReSS andWRF) and other regional models are also
used to elucidate systematic errors on the climate model due to the diurnal cycle. These
researches can contribute to ongoing international project “MAHASRI”. We aim to promotestudies in diurnal processes of convection/precipitation in the climate system in Japan.
On 14th July 2006, a domestic workshop, co-hosted by MAHASRI, was held on this topic
at Yokomaha Institute for Earth Sciences/ JAMSTEC. 13 presenters and many participants
attended the workshop, and valuable discussions were held on the issues described above.
On 9 th March, a second domestic workshop related to this research plan was held in
Hakone. Studies on diurnal cycle of cloud/precipitation systems, including a relationshipwith land terrain, an interaction between the diurnal cycle and intraseasonal variation,
long-term trend, etc, were presented. 13 presenters made presentations in the new scientificresults and made a lively discussion with many participants in the workshop.  

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High-Resolution Modeling of Atmospheric Water Circulation Systems
Using Cloud-Resolving Model
Clouds and precipitation systems have multi-scale structures ranging from a single-cellcloud to a large-scale weather system. Each class of the multi-scale structures has its own
properties and roles in precipitation systems. For simulations of the multi-scale structureof precipitation systems, extensive computation using a cloud-resolving model is necessary.
The purpose of this research is explicit simulations of clouds and organized precipitation
systems using the cloud-resolving model in a large domain and a very fine grid (less than 1km). In this research, we utilized the Cloud Resolving Storm Simulator (CReSS), which is a
cloud-resolving model developed for parallel computers. Using CReSS on the Earth
Simulator, we performed simulation experiments of important cloud and precipitation
systems.
One of the important objectives of high-resolution simulation is a typhoon. We briefly
summarize the result of the simulation experiment for Typhoon 0613 (T0613), which was
accompanied by intense tornadoes (“tatsumakis” in Japanese) along the east coast of
Kyushu. The horizontal grid spacing of the simulation experiment of T0613 was 500 m. The
CReSS model simulated the overall structure and movement of T0613 and detailed
structures of associated rainbands. Figure 1 shows a close-up view of the simulated
rainband, which formed to the east of Kyushu. The rainband is composed of convective
clouds. Some of these are super-cells, as indicated by the rectangle in the figure. The eastwest vertical cross section shows that one of the super-cells has a vault structure andintense vorticity in the cell (Fig. 2).

Figure 1 Close-up view of typhoon rainbands ob­
tained from a 500 m-resolution experi­
ment using the CReSS model at 0440
UTC, September 17, 2006. Gray scales
indicate the rain mixing ratio (g kg−1) at aheight of 1.91 km. Arrows are surface
wind vectors. The rectangle indicates aregion where super-cells are formed.

Figure 2 Vertical cross section along the zonal direc­­tion at latitude of 31.95 N obtained fromthe 500 m-resolution experiment at 0440
UTC, September 17, 2006. Gray scales are
the mixing ratio of precipitation (g kg −1)
and contours are vorticity (10−2 s−1).

A higher-resolution simulation with a horizontal grid size of 75 m was also performed
to simulate the tatsumaki. The detailed structure of the super-cell was simulated (Fig. 3). A
significant hook-shaped structure is formed in the southernmost part of the cell. The
intense tatsumaki is formed in the hook-shaped structure, which is indicated by the circle
in the figure. The maximum vorticity is 0.9 s−1 and pressure perturbation is 24 hPa. The

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vertical cross section (Fig. 4) shows that the tatsumaki extends up to a height of 2.5 km
with a leaning to the north. The cloud is lower in the central part of the tatsumaki. This issimilar to a funnel cloud.
The simulation experiments using the CReSS model range from the typhoon scale tothe tatsumaki scale, and resolve every class of the multi-scale structure. Such super-highresolution calculations provide detailed data concerning weather systems. Using the output
data of these experiments, modeling studies will clarify not only the structure of weather
systems but also the interaction between different classes of scale. High-resolution
simulations will contribute an accurate and quantitative prediction as well as prevention/
reduction of disasters caused by high-impact weather systems.

Figure 3 Super-cell with tatsumaki simulated in the
75 m-resolution experiment using theCReSS model at 0500 UTC, September
17, 2006. Gray scales are the rain mixing
ratio (g kg −1), and arrows are horizontal
wind vectors at a height of 200 m. The
circle indicates the tatsumaki forms in thesouthernmost part of the super-cell.

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Figure 4 Vertical cross section along the northsouth axis of the tatsumaki indicated by
the circle in Fig. 3. Gray scales are thecloud mixing ratio (g kg−1) and contours
are vorticity.

08.2.1 1:20:07 PM

Application of stable isotopes of water for evaluation of multi-scalewater cycle processes
Stable isotope ratios of water (δD & δ 18 O) and those anomalies from well-known
meteoric water line (d-excess = δD-8·δ 18 O) are good indicators to identify origins ofprecipitation, river water, groundwater etc. Since isotope ratios of water are controlled bykinetic or equilibrium fractionation processes in evaporation or condensation, the ratios
are applicable for evaluations of global water cycles as supporting tools for water balancecalculation, paleoclimate variations, and basin-scale hydrological studies.
HyARC is conducting mass spectral analyses of stable isotope ratios of water as one of
the HyARC Research Programs. In fiscal 2006, we comprehensively analyzed 2400 water
samples upon request from 11 domestic researchers.
We applied for a research grant to the Japan Society for the Promotion of Science (JSPS)
and were accepted for our research plan “Comprehensive Study on Meso-Scale Precipita­tion System with Use of Stable Isotope Ratios of Water” from fiscal 2005 through 2007. We
are also proposing several other methodologies to evaluate multi-scale water cycles in thehydrological processes of evapotranspiration, atmospheric boundary layer process, clouddevelopment, and precipitation processes. Our current targets are:
1) Use of stable isotope ratios of water to understand the mechanism of meso-scalewater cycle systems in coordination with other precise meteorological measurements(e.g., multi-band radars, radio soundings, and raindrop size measurements) together
with objective reanalyzed data sets, and
2) Use of stable isotope ratios of water to model multi-scale water cycle processes.
This research plan also aims to promote studies in isotope hydrology and to link
activities from the multi-scale point of view in water cycles among several research groups
in Japan. We are conducting annual science workshops related to this research plan. In
fiscal 2006, we held a workshop from 27 to 28, February 2007. Thirty-two participants
attended the workshop, and valuable discussions were held on the issues described above.

Observational study on atmosphere and ocean over and around
Okinawa Island
The National Institute of Information and Communication Technology (NICT)
established an observation center in Okinawa. The facilities of the center include a fullpolarimetric Doppler radar (COBRA), a 400-MHz wind profiler radar, a Doppler sodar,
disdrometers, rain gauges, and ocean radars. The collaboration between NICT Okinawa
and HyARC began in 2005. Utilization of the facility was encouraged as one of the interuniversity collaboration activities of HyARC.
Analyses of the polarization radar data, wind profiler data, and ocean radar data were
continued. The height characteristics of the bright band in the convective precipitation
system were investigated from COBRA data. Diurnal variation of the low-level jet in theBaiu season was revealed from the wind profiler radar data. A good comparison of theKuroshio current between the ocean radar data and the satellite data was obtained. Testlevel experiments including ocean observation using COBRA were also conducted. These
results were presented at a workshop at NICT Headquarters, Tokyo, in March 2007.

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Progress Reports

Projects
Progress of the 21st Century COE Program “Dynamics of the Sun–Earth–Life Interactive System (SELIS)”
Only one year is remaining before the 21st Century COE Program for the “Sun–Earth–Life Interactive System” (SELIS-COE) ends. During this program, we have promoted
interdisciplinary studies on the SELIS, such as the solar activity and glacier mass balance
and the role of vegetation in the climate system. Further studies are being conducted aspart of various science workshops. Since the 2004 school year, we have opened a specialclass on “Chikyu-gaku” (Study on the Earth) as part of graduate studies at the graduate
school of the environmental sciences. In this class, various COE-related professors givelectures on the earth system and its variations. Besides the class, we are currently preparing
a comprehensive textbook on “Chikyu-gaku,” which will be issued in fall 2007.
The SELIS-COE program organized an international symposium on “Dynamics of theIce Age Climate” in Nagoya on November 13–15, 2006. The aim of this program was tointegrate the updated information and knowledge on the Ice Age climate reconstruction
and modeling, and to comprehensively discuss some unresolved key issues on the Ice Ageclimate in the past several million years. This will also have deep implications for thecurrent global-warming climate issue. The following keynote speakers were invited fromabroad: Jean Jouzel (ice core studies for Antarctica), An Zhishang (sediment studies for the
Chinese Loess Plateau), Alexander Prokopenko (sediment core studies for Lake Baikal),
Shukuro Manabe (General Circulation Model (GCM) studies), Bette L. Otto-Bliesner (GCM
studies), Andrey Ganopolski (Earth System Model for Intermediate Complexity (EMIC)
studies), and Michel Crucifix (EMIC & GCM studies). The following topics were discussed
in the symposium:1) What caused the transition of global glaciation features (i.e., periodicity, skewness,and responses to insolation) from the Pliocene to the Pleistocene (5–3 Ma)? 2) What caused
the transition in the glacial cycles (from 40- to 100-kyr cycles) around 1 Ma? 3) Modulationof glacial cycles during 1 Ma. 4) What triggers the interglacial to glacial phase in the
100-kyr cycle? 5) Millennial-scale events in the last glacial period.
More than 100 scientists participated in this symposium, and they had heated discus­
sions for the entire three day period.

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10Core Research for Evolutional Science and Technology (CREST)l Lower Atmosphere and Precipitation Study (LAPS)The Lower Atmosphere and Precipitation Study (LAPS) is one of the projects of theCore Research for Evolutional Science and Technology (CREST) of the Japan Science andTechnology Agency (JST). The CREST projects are conducted with strategic research
themes (http://www.jst.go.jp/kisoken/en). LAPS comes under the theme of “R&D in
Hydrological Modeling and Water Resources Systems” supervised by Prof. K. Musiake,
Fukushima University. The objective of LAPS is to clarify the relationship between theplanetary boundary layer (PBL) and the precipitation system. This year was the final yearof this project, and the results were presented at the CREST water theme symposium andour internal workshop.
Important results are the seasonal change in the atmospheric boundary layer (ABL) andthe large eddy simulation (LES). The observation showed the changes in the sensible andlatent heat fluxes from the surface and the development of the ABL according to thechanges in the surface conditions. The observation, however, does not show the profiles ofthe fluxes in the ABL. The simulations were based on the observation, and after confirmingthat the simulation reproduced the observation results well, the internal structures of both
the ABL and the fluxes were obtained. The results may be summarized as follows. Over dry
land, the profile of the fluxes is like a textbook one, i.e., a sensible heat flux with its
maximum at the surface is the primary driving force of the ABL. The entrainment layer isalso well reproduced. Over wet land, the development of the ABL is weak and water vapor
contribution to the buoyancy flux is important. Over sub-tropical ocean, the flux is small
and water vapor contribution to the buoyancy flux is of primary importance. Over
undulating terrain, the orographic uplift is also important.

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11
Solution Oriented Research in Science and Technology (SORST)
l Satellite Monitoring of Ocean Primary Productivity

Oceans comprise the largest reservoir of water and carbon dioxide on the Earth’s
surface; hence, the air-sea exchange of water and carbon dioxide plays a central role indetermining the planet’s climate system. Air-sea exchanges of heat (water) and carbon
dioxide are affected by phytoplankton, since these organisms determine the opticalproperties of near-surface oceans and absorb carbon dioxide through primary productivity.
Quantitative knowledge of the abundance and productivity of phytoplankton on a global
scale is required for a mechanistic understanding of their regulating processes to improveclimate prediction models and thus better predict climate variability. Practically speaking,this knowledge and understanding is attained only by means of satellite observations, but
because of difficulties in obtaining in situ data for validation, the satellite data are yet to be
fully exploited.
To overcome these difficulties, we have been developing an in situ ocean primary
productivity monitoring system to validate primary productivity data obtained fromsatellites. Comprising an underwater winch system with a profiler buoy equipped with afast repetition rate fluorometer, the system was successfully developed with the support of
the Japan Science and Technology Agency’s Core Research for Evolutional Science andTechnology program. Following the system’s development, a continuation project, “Satellite
Monitoring of Ocean Primary Productivity (SMOPP),” was approved by JST in the Solution
Oriented Research for Science and Technology Program in 2004. The goal of the SMOPP
project is to design an operational system to monitor ocean primary productivity on a
global scale. To achieve this goal, we plan to conduct routine operation of the monitoring
system and obtain validated time-series satellite data of primary productivity, which is to be
utilized in combination with other time-series satellite data on physical forcing parameterson the ocean surface for process studies of the response of ocean biology to the atmos­
pheric forcing on the ocean.
Research activities in FY 2006 on the SMOPP project are described separately in theactivity report of the Ocean Climate Biology Lab, with notable achievements including
successful operation in the deep western subarctic Pacific for 1.5 months and completion of
two full sets of underwater winch systems for continuous time-series operation. As for thePrimary Productivity Pofiler, we continued efforts to conduct measurements to the greatest
possible extent in various environments, such as the northern North Pacific, Bering Sea,
East China Sea, Sea of Japan, and Upper Gulf of Thailand, in addition to Sagami Bay,
where test mooring of the buoy system is being carried out.
The process study using multi-parameter satellite data will be carried out for Sagami
Bay. To validate the satellite-based process study, cruises of JAMSTEC’s Tansei Maru as well
as development of the physical-biogeochemical model were conducted for observational
studies of rate processes relating to oxygen metabolism in the bay.

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12

Division of Regional – Scale Water Cycle Processes
Laboratory of Meteorology
Characteristics of mesoscale convective systems over the east part of continental China
during the Meiyu period from 2001 to 2003
Hefei Doppler radar observation data over the downstream region of the Yangtze Riverduring the Meiyu period from 2001 to 2003 were analyzed to reveal the predominant
structural characteristics of meso-β -scale convective systems (Mβ CSs) around the Meiyu
front. Convective and stratiform portions were separated from Mβ CSs using the brightband fraction (BBF) method. The daily and yearly mean vertical profiles of radar reflectivity
for the convective portion were calculated.
Results showed that the vertical profile of the convective portion of Mβ CSs for 3 years
was characterized by low-altitude radar reflectivity peaks (around 3 km) and large decreaseof reflectivity with height above the melting level (Fig. 1). To understand these characteristics of Mβ CSs, the convection of medium depth (CMD) is defined as a group of convective
cells whose echo-top height with a reflectivity of 15 dBZ is equal to or less than 8 km, andthe reflectivity peak is below 4 km throughout their lifetime.
To investigate the structural characteristics of Mβ CSs around the Meiyu front, observed
Mβ CSs were categorized into slow-moving (≦3 m s–1) and south-of-front (SSF) type, slowmoving and along-the-front (SAF) type, fast-moving (≧7 m s–1) and along-the-front (FAF)
type, and slow-moving and north-of-front (SNF) type according to their movement speed
and their locations relative to the surface front (Fig. 2). The predominant convection in the
SSF type was the CMD, which covered 51% of the convective area. The CMD and deep
convections (DC) coexisted in the SAF, with the CMD covering 34% of the convective area.
The FAF type was organized from the DC, and the SNF type primarily consisted of the
CMD. The environmental conditions under which the SSF type formed were characterized
by a weak wind convergence (<2 × 10 −5 s –1 ) near the surface, a low level of neutral
buoyancy, and humid atmosphere below the middle level. The large contribution of the
CMD to the convective rainfall amount in the SSF type and its non-negligible contribution
to the SAF type indicate that the CMD is one of the main structures of the Meiyu frontal
convective precipitation system.

Fig. 1 Yearly mean vertical profile of reflectivity forconvective and stratiform portions identified
by the BBF method in 2001, 2002, and 2003
within a radar radius of 60 km.

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Fig. 2 Schematic illustration of convections for fourtypes of meso-β -scale convective systems
around the Meiyu front. The thick solid line
indicates the surface front. The dashed line
passing through the cloud represents the melt­
ing level. CMD and DC represent convectionof medium depth and deep convection, re­spectively. The black ellipse represents theconvection core. The line surrounding theblack ellipse represents the precipitation re­gion.

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13
Statistical features of precipitation cells observed in East Asia during the Meiyu/Baiu period
To clarify the statistical features of precipitation cells during the Meiyu/Baiu period,
Doppler radar data obtained at Shouxian, Anhui Province, China (continental area) from
June 17 to July 17, 1998, at Zhouzhuang, Jiangsu Province, China (coastal area) from June
10 to July 13, 2001, and at Okinawa (oceanic area) from May 27 to June 11, 2004 areanalyzed. From the radiosonde observations, moist layers were found to exist in the lower(less than 2 km) and middle troposphere (from 2 to 5 km). The following features ofprecipitation cells over the moist environment in East Asia are obtained: area (horizontal
scale), echo-top height, height of maximum reflectivity in each precipitation cell, andvertical gradient of maximum reflectivity above the melting level. In particular, echo-top
height and vertical gradient of maximum reflectivity above the melting level are describedin detail.
The numbers of analyzed precipitation cells are 2978 at Shouxian, 17529 at Zhouzhuang, and 5093 at Okinawa. The averaged areas of precipitation cells are 16.8 km2 at
Shouxian, 22.8 km2 at Zhouzhuang, and 16.4 km2 at Okinawa. There is a tendency for thehigher precipitation cells to have a larger area, although this is not clear for cells over 20
km2.
Figure 3 shows the integrated probability density of echo-top height. The ratio of echotop height that does not exceed the height of the melting level + 1 km is 69.0% at Shouxian,
74.1% at Zhouzhuang, and 80.8% at Okinawa. Precipitation by warm rain should be
effective in these areas.
Figure 4 shows vertical profiles of maximum reflectivity at each level. The fact that thevertical gradient of reflectivity above the melting level over the oceanic area is larger thanthat over the continental area is well known. However, in this study, the vertical gradient ofreflectivity above the melting level at Zhouzhuang (coastal area) and Shouxian (continentalarea) is not obviously small compared with Okinawa (oceanic area). These observations canbe attributed to the moist condition in the lower and middle troposphere. In this condition,
it would be difficult to develop deep convection because convective instability is easily
consumed by convection and is not accumulated. Therefore, almost all of the precipitation
cells in the moist environment frequently observed in East Asia during the Meiyu/Baiu
period have echo-top heights that reach only to the melting level + 1 km and large verticalgradient of reflectivity above the melting level.

Fig. 3 Integrated probability density of echo-top
height at each area. Solid, broken, anddashed lines show Okinawa, Zhouzhuang,and Shouxian, respectively.

001.HyARC2006-E.indd 13

Fig. 4 Vertical profiles of maximum reflectivity.
Thick solid, thick broken, and thick dashedlines show Okinawa, Zhouzhuang, andShouxian, respectively. Thin solid, thin bro­ken, thin dashed, and thin double-dashedlines show Oklahoma (continental), Taiwan(oceanic), Darwin (continental), and Darwin(oceanic) from Zipser and Lutz (1994), re­spectively.

08.2.1 1:20:11 PM14Detailed structure of velocity and moisture fields around the Baiu frontal zone
Previous studies have revealed that the Baiu frontal zone has complicated rainfall
distributions. Moteki et al. (2004) revealed the detailed wind and moisture fields that
determine one of the typical Baiu frontal rainfall distributions. There were three
airstreams: cold and dry northeasterly, oceanic southwesterly, and comparatively moist
continental airstream from the west. On June 27, 2004, we conducted aircraft observationof the Baiu frontal zone around the East China Sea to reveal these structures and found a
new cloud pattern unaccountable by the structure shown in Moteki et al. (2004). Thisimplies another structure in the Baiu frontal zone.
Therefore, we conducted another aircraft observation on June 23, 2005. First, we observed the meridional profile at 500 m from 31°N to 25.5°N along 125.9°E. Second, we conducted dropsonde soundings from 12000 m at 4 points (25.9°N, 27.0°N, 28.0°N, and 29.5°N).
Figure 5 shows the results of the 500 m flight. There are two ascending areas: X was
weak and wide (28–29.8°N); Y was strong and narrow (26.2–26.8°N). Corresponding tothese ascending areas, there were two wind shears: northeast-southwest for X and westsouthwest for Y, respectively. Ascending area X had weak precipitation, while ascendingarea Y had heavy rainfall. Moisture contrast was apparent around the northern edge of theascending area X. Figure 6 shows the results of dropsonde soundings. Dropsonde points
were located at the north and south sides of each ascending area. To the south of theascending area Y (dropsonde 1), the lower level below 500 m was very moist and convective
unstable. To the north of the ascending area Y (dropsonde 2) and south of the ascendingarea X (dropsonde 3), the atmosphere was comparatively moist and weakly convective
unstable. To the north of the ascending area X (dropsonde 4), there was convective neutral
stratification and low-level cold inflow.
To understand the detailed structure of the Baiu frontal zone, we performed numericalsimulations using the Cloud Resolving Storm Simulator (CReSS). Back-trajectory analysis
revealed the wind field around the Baiu frontal zone. As shown in Fig. 7, there were four
airstreams: northeasterly, west-southwesterly, southwesterly-1, and southwesterly-2. The
atmospheric properties of these airstreams correspond to the features shown in dropsonde
4, 3, 2, and 1, respectively. The convergence among these four airstreams, which had
different moisture stratifications, resulted in northern weak and southern heavy rainfall.

Fig. 6 Vertical profiles of equivalent potential
temperature obtained from the dropsonde
soundings.

Fig. 5 Meridional profiles of horizontal wind, verti­
cal wind, temperature and dewpoint tempera­ture, and equivalent potential temperatureand mixing ratio of water vapor on June 26,
2005.

001.HyARC2006-E.indd 14

Fig. 7 Back-trajectory ana­
lysis chasing 30 air­masses at 500 m
height along 125.5°
E. Gray scale shows
altitude.

08.2.1 1:20:13 PM

15Structure of cloud cluster observed by Doppler radar in the tropical western Pacific region on
July 1–2, 2005
The aim of this study is to examine the structure of cloud clusters that develop into
tropical cyclones in the tropical western Pacific region. We carried out observations on
cloud clusters with two Doppler radars in the Republic of Palau in the tropical western
Pacific region from June to July 2005. A cloud cluster of 1000-km diameter passed theRepublic of Palau from July 1 to 2 (Fig. 8) and developed into a tropical cyclone over thePhilippines from July 3 to 4. In this study, the structure of the cloud cluster was examined
in detail with Doppler radar data before its development into a tropical cyclone.
With GOES-IR data, the west of the cloud cluster consisted of a long-lived mesoscaleconvective system (MCS) lasting about 36 h (Fig. 8). The major and minor axes of the MCS
were about 400 and 300 km, respectively.
With Doppler radar data, the structure of the MCS was examined. The MCS moved to
the west at a speed of 5 ms−1, and a line-shaped rainband formed ahead of the MCS. The
stratiform region is located on the eastern side of the line-shaped rainband (convective
region) in the MCS. In the stratiform region, a mesoscale vortex at the middle level (from 3
to 8 km) was analyzed assuming that a system was steady (Fig. 9). The vorticity was 7.3 ×
10–5 s–1 with a diameter of 323 km by a calculation with several assumptions.
The long-lived MCS with a developed line-shaped rainband in the west part of the cloudcluster moved westward after the cloud cluster decay. The cloud area of the MCS split at 00
UTC on July 3 and a newly developed convective area moved north and developed into thetropical cyclone over the Philippines. In other words, the tracked MCS was a system thatdeveloped into the tropical cyclone. Recent studies showed that a developed mesoscalevortex in MCS greatly contributed to the development of tropical cyclones. The
characteristics of the mesoscale vortex (i.e., depth, horizontal scale, and vorticity) shown inthis study were compared with those of previous studies, and the order of the vorticity was
the same; that is, the observed MCS that developed into a tropical cyclone after 48 hours
had a vortex in the middle troposphere. This study suggested the necessity to observe andtrack the mesoscale vortexes 48 hours before their development into the tropical cyclone.

Fig. 8 GOES-IR image at 00UTC 2 July around
Palau. The location of Palau is indicated byan arrow. The ellipse indicates the target
MCS.

001.HyARC2006-E.indd 15

Fig. 9 Time-height cross section of horizontal wind(arrows) and their meridional component(shades) when the MCS passed.

08.2.1 1:20:16 PM

16The structure and formation process of the selectively developed snowband over the Sea ofJapan in winterFor the purpose of understanding mesoscale winter snow storms, Nagoya University
installed a dual Doppler radar system on the coast of the Sea of Japan from December 2002
to February 2003. On January 29, 2003, strong cold air moved over northern Japan andactive snow clouds were observed over the Sea of Japan. On this day, during the period
from 18 JST to 20 JST, the dual Doppler Radar system observed a selectively developed
snowband whose echo-top height exceeded 5 km. The snowband was different from thedisturbance associated with the Japan Sea Polar-airmass Convergence Zone (JPCZ), andthe influence of geographical features and land breeze were not found. To reveal thestructure and formation process of the developed snowband, we investigated the dual
Doppler radar data and numerical simulation model CReSS.
From the Doppler radar observation, convective cells, which compose the snowband,
developed both upstream and downstream of the snowband and lined up along thepredominant wind direction and organized linear structure (Fig. 10). In the lower layer,
west-northwesterly wind was observed on the north side of the snowband, while westerly
wind was observed on the south side. A clear convergence line was formed along thesnowband in the lower layer. In particular, at the downstream region of the snowband, thenortherly inflow from a long distance was observed on the north side of the snowband andthe low-level convergence was intensified. An enhancement of the low-level convergencecontributed to the longevity of the convective cells that developed in the upstream region of
the snowband and to the occurrence of convective cells in the downstream region of thesnowband. Therefore, this played an important role in maintaining the linear structure of
the snowband.
As a result of numerical experiments, when the snowfall system associated with the
JPCZ began to decay, the corresponding snowband formed on the south side of the JPCZ.
In the lower level, cold air was present in the southern edge of the snowband and highequivalent potential temperature air was inflowing from the north side (Fig. 11). Owing to
the convergence of these airmasses, high equivalent potential temperature airmass was
uplifted and formed convective cells. As a result, the snowband developed on the south sideof the JPCZ. Furthermore, it is important to reach high equivalent potential temperature
airmass to the south of the JPCZ. The snowfall system associated with the JPCZ should bein the decaying stage because the upper layer cold air was moving away from the Sea ofJapan, and the stability of the atmosphere was increasing.
Snowband associated with JPCZ

Northerly inflow from a long distance

Convergence line

Enhancement of
low level convergence

Cold Air

UpdraftOccurrence of Cells
Occurrence of Cells
Upstream

COAST LINE
Downstream

Fig. 10 The basic concept of the snowband structure
shown by dual Doppler radar data analysis.
Arrows show relative wind direction for thestorm, and circles represent convective cells.

001.HyARC2006-E.indd 16

Cold Air Convergence

Inflow of high equivalentpotential temperature

Fig. 11 The process of the snowband was selectively
developed south side of the JPCZ. When thesnowfall system associated with the JPCZ is in
the decaying stage, high potential temperature
air can reach the south side of JPCZ.

08.2.1 1:20:18 PM

17Development of the Lightning Simulator
We developed a Lightning Simulator that simulates charge distribution inthunderstorms and lightning on the basis of the Cloud Resolving Storm Simulator (CReSS).
Lightning activity of thunderstorms was simulated in two steps. The first step was theaccumulation of electric charge by charging of cloud particles. The second step wasdischarge by lightning. In developing the Lightning Simulator, we introduced variables ofcharge as a prediction variable in the CReSS. First, we used the riming electrification: ice
crystal, snow, and graupel that took charge in the microphysical process. Then, we
described the formation of charge by riming electrification. Next, we calculated the electric
potential and electric field from the charge distribution. We used the lightning
parameterization that used the electric field as the threshold value of lightning initiationand parameterized discharge.
Thunderstorms that took lightning on the ground in summer formed the tripole
structure of the charge distribution: the positively charged region in the upper layer, thenegatively charged region in the middle layer, and the small positively charged region in thelower layer. We performed the ideal two-dimensional experiment to examine thereproducibility of the tripole structure of charge distribution within the riming electrifi­
cation and lightning parameterization. The horizontal resolution was 500 m and artifactual
sounding data were used as initial field. Simulated thunderstorms took the cloud-to-ground
discharges and cloud flashes. The tripole structure of the charge distribution was formed in
the model (Fig. 12).
Next, we performed a three-dimensional experiment of the thunderstorms developed
over Aichi Prefecture of Japan on August 12, 2006. We compared the lightning strike points
in the model with those observed by the Lightning Location System (LLS) operated by
Chubu Electric Power Co., Inc. The horizontal resolution is 4 km and realistic environment
data is used as the initial field. Although the timing and area of the lightning strikes were
not exactly simulated in the model, we could reproduce the lightning strikes over the Aichi
Prefecture with thunderstorms (Fig. 13). In this experiment, the Lightning Simulator could
simulate the thunderstorm that took the lightning on the ground.

Fig. 12 A vertical cross section of total net charge ofcloud water, rain, ice crystal, snow, andgraupel at 3900 s. Shade represents net
charge (C km–3); solid line represents cloudborder, and broken lines denote temperature(°C).
Fig. 13 Frequency of simulated lightning in threedimensional experiment.

001.HyARC2006-E.indd 17

08.2.1 1:20:20 PM

18Laboratory for Climate System Study
Propagating diurnal disturbance embedded in the Madden-Julian Oscillation
Deep cumulus convection and heavy precipitation associated with the diurnal cycle
over the Maritime Continent including the Indonesian Archipelago play an essential role in
the Earth’s climate system through a huge latent heat release. This world convection centeris subject to the eastward propagating planetary-scale atmospheric disturbance called theMadden-Julian Oscillation (MJO), which originates over the Indian Ocean with aperiodicity of about 30–60 days. Associated with the passage of a large-scale atmosphericdisturbance, the modulation of the diurnal cycle over the islands has been observed.
However, how the large-scale disturbance of the MJO modulates or is modulated by thediurnal cycle of convection/rainfall over the islands is not clear. Here, by using highresolution TRMM precipitation data, we present the detail of actual rainfall activity that
occurs under the large-scale MJO convection system. In this study, we investigated the MJO
that propagated during the period from January to February 2001.
In order to elucidate the MJO space-time internal structure, the time-longitude diagrams of 3 hourly TRMM 3B42 rainfall averaged between 4°S–1°S during the end of January through February 2001, superimposed on the outgoing longwave radiation (OLR)(shaded) and zonal wind at 600 hPa (white contour), are shown in Fig. 1. Because the diurnal cycle was the most dominant mode in rainfall variability, a high-pass filter was applied
to the data in order to extract the diurnal cycle component for TRMM rainfall data. The eastward propagation ofdeep convection (OLR) followed by the
600 hPa height westerly wind was apparent at a phase speed of about 3–4 m
s–1. Under the large-scale convection,
the high-frequency variability in rainfall exhibited a significant eastward or
westward propagation that is likely related to the background low-mid levelwind. At the evolving stage of the MJO(end of January), aside from the standing oscillating rainfall over the western
Indian Ocean (60°E), the westward
propagating disturbances dominatedto the west of the Maritime Continent(80°–120°E), intruding on the eastern
Indian Ocean. Part of the westward
propagating signal was triggered byeach island and is associated with thediurnal rainfall over the islands.
In February, on the other hand, theeastward propagating diurnal distur- Fig. 1 Time-longitude cross section of the diurnal cycle
bance (PDD) became pronounced overfiltered 3 hourly rainfall anomaly (contour: 0.2, 0.4
mm h–1) are averaged between 4°S and 1°S from late
the whole Maritime Continent fromJanuary through February 2001. OLR (shaded) andthe Indian Ocean to the Pacific as thezonalwind at 600 hPa (contour: solid, 2 m s – 1 ;center of the large-scale convection
dashed, 10 m s – 1 ) averaged between 5°S andreached the major islands and theequator are also described. The island terrain thatwesterly prevailed. It should be noticed
averaged between 4°S and 1°S is denoted at thethat the significant PDDs, which cut
b o t t o m . B l a ck s o l i d l i n e c o r r e s p o n d s t o t h ethrough the Maritime Continent from
penetrating diurnal disturbances (see text for details).

001.HyARC2006-E.indd 18

08.2.1 1:20:22 PM

19100°E to 160°E, appeared during February 6–11 (black solid line). The inferred phase speedof the propagating disturbances was about 15–20 m s–1, which was close to the 600-hPa
wind speed. These eastward PDDs are likely to play an important role in the propagation of
the large-scale MJO convection. In association with the penetration of PDDs through the islands, the center of rainfall activity shifted from the western part of the Maritime Continent
to the east. The PDDs, which started around 130°E–140°E and propagated toward the Pacific, became pronounced after February 16. On the other hand, the rainfall over the islands
became rather scarce following the pervasive PDDs after February 10 between the significant rainfall over the Indian Ocean and the Pacific. The other noticeable feature is that thewesterly area expanded eastward incrementally over the western Pacific in association withthe eastward movement of the PDDs.
It is interesting to note that the timing of the PDDs (February 6–11, 2001) was con­sistent with a passage of the planetary-scale Kelvin wave (Masunaga et al. 2006) over the
Maritime Continent. The dynamics of these PDDs across the Maritime Continent are notclear yet, but the penetration of the PDDs might be triggered by the large-scale equatorial
wave as well as advection by the background westerly. Our results demonstrate that thediurnal cycle of convection over and around the major islands thus plays an active role in
the propagation of the MJO over the Maritime Continent.

Role of the Tibetan Plateau and the Rocky Mountains in shaping the ocean climate in the
North Pacific and North Atlantic
We examined the individual effects of the Tibetan Plateau and the Rocky Mountains on
the ocean surface climate in the North Pacific and the North Atlantic using a coupledgeneral circulation model (GCM-I) of the Meteorological Research Institute (MRI). For thesummer anticyclone in the North Pacific, the Tibetan Plateau and the Rockies show
comparable effects on the spatial features of pressure rise. However, in the eastern North
Pacific, a relatively large rise in sea level pressure (SLP) occurs because of the Rockies. The
Rockies create lower sea surface temperatures (SSTs) in the southeastern North Pacificthan the Tibetan Plateau through air-sea interactions, such as a decrease in shortwave
radiation flux to the ocean, increase in latent heat flux from the ocean, intensified
upwelling, and cooler water transported from the north.
On the other hand, in the western subtropical North Pacific, an increase in SSTs due tothe Tibetan Plateau is found year round and is particularly outstanding in spring. The
enhanced winter subtropical anticyclone in the southeastern North Pacific due to thepresence of the Tibetan Plateau creates ocean currents that transport warm sea water fromthe lower latitudes north to the western North Pacific. Therefore, SSTs in the western
subtropical North Pacific increase because of the presence of the Tibetan Plateau. The
higher SSTs in spring influence the summer surface climate of this ocean area, such asincreasing precipitation. For these reasons, the zonal asymmetry of SSTs in the subtropicalNorth Pacific is emphasized by the presence of both the Tibetan Plateau and the Rockies.
Figure 2 shows the ratio of the absolute value of the annual mean SST difference due tothe Tibetan Plateau to that due to the Tibetan Plateau plus the Rockies, to present a spatial
feature of the effect of the Tibetan Plateau contribution on annual mean SST differences. In
the western North Pacific west of 180° along 20–30°N, a ratio above 0.7 was found,suggesting that the effect of the Tibetan Plateau was larger than that of the Rockies.
The presence of the Tibetan Plateau lowers SST in the lower latitude region of theNorth Atlantic by enhancing anticyclonic circulation that changes air-sea interactions;however, the Rockies do not have such an impact. The decrease in SST due to the Tibetan
Plateau occurs notably in summer.

001.HyARC2006-E.indd 19

08.2.1 1:20:22 PM

20Fig. 2 Ratio of the absolute value of the annual mean SST difference due tothe Tibetan Plateau to that due to the Tibetan Plateau plus the Rockies.
The contour interval is 0.1, and the area above 0.5 is shaded.

Reference
Manabu Abe, Akio Kitoh, Tetsuzo Yasunari, and Osamu Arakawa: Role of the Tibetan Plateau and the
Rocky mountains in shaping the ocean climate in the North Pacific and North Atlantic, Climate
Dynamics (submitted).

Decreasing trend in rainfall over Indochina: Impacts of tropical cyclones
Recently, Intergovernmental Panel for Climate Change (IPCC) reported human-induced
global climate change. Over the Indochina Peninsula, the long-term decreasing trend in
rainfall was noted. Previous study suggested that the deforestation in northern Thailand
induced the decrease in rainfall over Thailand. However, the decreasing trend in rainfall
could be affected by the changes in large-scale circulation, which are unknown, resulting inhuman-induced climate change or natural variability.

Fig. 3 Lag composite analysis of geopotential
heights and winds anomalies at 850 hPa
are shown. Based on daily rainfall overThailand, 190 cases of high rainfall day(rainfall amount on a day exceeds 1
standard deviation from the mean) areselected. The anomalies were departuresfrom the 43-year September mean ofeach variable. Gray shade shows thatgeopotential height anomalies are lessthan −8 gpm. The data is ERA-40 reanal­
ysis derived by the European Centre for
Medium-Range Weather Forecasting.

001.HyARC2006-E.indd 20

08.2.1 1:20:24 PM

21This study addressed a decreasing trend in rainfall during the late summer monsoon
season (September) in Thailand from 1951 to 2000 and associated changes in large-scale
circulations and tropical cyclone (TC) activity. Thailand receives significant rainfall during
May to October and experiences two rainy peaks in late May to early June and September.
Rainfall over Thailand in September was mainly brought by the westward propagating TC
activity from the South China Sea and western North Pacific. The long-term trend in
rainfall during the late summer monsoon season was closely associated with the number oflandfalling TCs over the Indochina Peninsula. The change in the number of landfalling TCs
over the Indochina Peninsula was likely caused by changes in the major cluster of TC
tracks. Concurrent with the changes in TC tracks, the steering current of TCs was changed,
which is likely to be associated with the strength of the subtropical high over the western
North Pacific.

Fig. 4 Tropical Cyclone Tracks (derived from the Japan Meteorological Agency) in
September in each period (P1: 1951–1965, P2: 1966–1980, P3: 1981–1995).

001.HyARC2006-E.indd 21

08.2.1 1:20:25 PM

22Laboratory for Cloud and Precipitation Climatology
Categorizing tropical rainfall based on satellite data
Precipitating clouds in the Tropics can be classified into different components in termsof cloud height and heaviness of rain. The most abundant component is shallow cumulus.
Shallow cumulus does not reach the freezing level and produces moderate rainfall in theabsence of frozen hydrometeors. Cumulus congestus grows to above the freezing level,yielding more rainfall than shallow clouds, although the cloud top is not as high as thetropopause. A deep convective core is a tall cumulus tower penetrating the whole
troposphere, where rain drops melted from large ice particles (snow, graupel, and hail)created above the freezing level result in heavy rainfall. Deep convective cores are often
surrounded by stratiform rain. Stratiform regions tend to be less turbulent and lower inrain rate than deep convective cores; however, they produce rainfall across a much wider
area than convective cores do.
Figure 1 shows the joint histogram of precipitation heightand cloud height analyzed from Tropical Rainfall Measuring
Mission (TRMM) Precipitation Radar (PR) and Visible/Infrared
Scanner (VIRS) infrared brightness temperature. The four storm
categories of Shallow, Cumulus Congestus, Deep Stratiform, andDeep Convective are defined based on Fig. 1.
Relative significance among the different storm categories
varies with geographical regions, seasons, and El Niño Southern
Oscillation (ENSO) phases. Time series of the probability ofrainfall occurrence are plotted in Fig. 2 for different storm Fig. 1 Storm categories de­fined in the joint his­
categories and for various tropical regions. Deep stratiform andtogram of radar echoconvective systems are observed more often than shallow and
top height and infra­
cumulus congestus clouds in the West Pacific and Indian Ocean.
red brightness tem­
In contrast, the shallow category is the dominant component
perature (IR Tb).
most of the time in the Central Pacific. A key to understanding
this regional contrast lies in large-scale ascent or subsidence (indicated by histograms).
Deep stratiform and convective systems are commonly found in association with largescale ascent (upward bars), while they tend to be overwhelmed by shallow clouds in theabsence of strong ascent or under subsidence (downward bars). Deep systems can warm
the surrounding atmosphere by latent heat release that works as a pump to generate largescale circulation. The subsiding branch of the circulation caps the lower troposphereknown as the planetary boundary layer (PBL). This cap, or the trade inversion, suppresses
deep convective activity. It allows only shallow cumulus to barely emerge from the PBL.
The storm categorization proposed here is useful for monitoring the variability of tropicalprecipitating clouds. Continuing research is underway to further deepen our climatologicalknowledge by applying the present methodology to longer-term data.

Fig. 2   Time series of the frequency of rainfall occurrence for different storm categories.

001.HyARC2006-E.indd 22

08.2.1 1:20:26 PM

23
Observational study on the Madden-Julian Oscillation and tropical waves in the atmosphere
In the early 1970s, Roland Madden and Paul Julian
discovered an eastward propagating mode recorded inweather station data over the Tropics. They named thismode “the 40–50 day oscillation” after its oscillatory
period, which is now better known as the MaddenJulian Oscillation or MJO. The MJO has drawn
increasing attention since it is the most outstanding
component of tropical intraseasonal variability. Our
understanding of the MJO has improved by manysuccessful studies over the past 30+ years. Nevertheless,it would be fair to say that no single theory has
succeeded in explaining every aspect of the MJO.
This study investigates the potential roles of the
Kelvin and equatorial Rossby (ER) waves in MJO propagation by a composite analysis described as follows:
The geographical center of MJO convection, hereafter
called the base point (“x”s in Fig. 3), is first identified ineach snapshot. Next, look east and west standing on
the base point to find the Kelvin and ER waves, defined
again by filtered outgoing longwave radiation (OLR)
using proper bandpass filters. Repeating this procedure
over 25 years of OLR data, a number of snapshots, Fig. 3 An OLR-filtered MJO event. Sol­id (dashed) lines depict negative
longitudinally offset to the base point, are averaged(positive) OLR anomaly.
together.
Figure 4 shows a lag composite diagram for the austral summer MJO. The Kelvin wave
(shaded) approaches from the west to the MJO convection center (or 0 in abscissa) prior to
the MJO peak phase (or Day 0 in ordinate). The Kelvin wave finally arrives in the close vicinity of the MJO convection center on Day 0 andpropagates further to the east once the peak phasehas passed. In contrast, the ER wave (contoured),loosely concentrated around the 0 longitude for negative lags, exhibits little systematic pattern in thecomposite diagram. A comprehensive examinationof multiple analyses including several case studies(not shown) suggests that (1) the Kelvin wave has animportant role in MJO propagation and that (2) theinteraction with the ER wave over the west PacificFig. 4 The Kelvin wave (shaded) and ER warm pool leads to convective intensification, whichwave (contoured) composited around gives rise to the peak phase of the MJO.
the MJO convection center.

Satellite Data Simulator Unit
A crucial component of remote-sensing retrieval algorithms is radiative transfer
simulation to synthesize satellite measurements. Computational schemes to solve radiativetransfer problems are in general individually optimized to different kinds of sensors forpractical reasons. Recent Earth observing satellites carrying multiple sensors, however,
have led to increasing demands for a radiative transfer code applicable uniformly todifferent types of sensors. In response to such demands, we have developed the Satellite
Data Simulator Unit (SDSU) for use by spaceborne microwave radiometers, radars, andvisible/infrared imagers, which is available online from http://precip.hyarc.nagoya-u.ac.jp/
sdsu/sdsu-main.html. Potential application of the SDSU package is not only limited toretrieval algorithm development but also includes cloud-resolving models (CRMs). It would
help test and improve CRM performance to assess simulated measurements of various
satellite sensors in comparison with actual observations.

001.HyARC2006-E.indd 23

08.2.1 1:20:26 PM

24Division of Global – Scale Water Cycle Variations
Laboratory of Satellite Meteorology
Precipitation system study using satellite data
Satellite data are invaluable for a precipitation system study over a vast ocean. The
Tropical Rainfall Measuring Mission (TRMM) satellite is equipped with a precipitation
radar (PR), microwave radiometer (TMI), visible/infrared radiometer, and others. Originally
TRMM was intended to study tropical rain systems. However, after more than nine years ofoperation, it was recognized that TRMM data are also useful for mid-latitude precipitation
study. Here, so-called empirical orthogonal function (EOF) analysis was applied to the TMI
signatures (Tb’s) for the precipitation systems over the ocean near the Japan Islands.
The first principal function (EOF1) correlates with the near-surface rain rate due toemission from liquid water. All channels contribute equally to the variation except the85.5-GHz channel in the summer case. This exception may be because summer precipita­tion is likely associated with the formation of many solid particles during the developmentof the system. The second EOF (EOF2) represents the amount of solid particles and also
the near-surface rain rate. EOF2 largely varies with echo top height in summer and withboth echo top height and freezing height in winter. EOF3 seems to represent the
precipitation types.
This result suggests that the precipitation systems can be categorized by the microwave
signatures. This categorization could improve the rain-rate estimation using microwave
radiometers.

Fig. 1 Left-hand panels: Eigenvalues of TMI nine-channel Tb’s and their percentiles of explained variance (thefirst column) in JJA. Center panels: CFAD of Z derived from PR 2A25 data (gray image, percentage
every altitude), and histograms of the cloud top height (CloudH, dashed line), the rain height (StormH,
solid line), the freezing height in 2A23 (FreezHPR2A23, thin dotted line), the freezing height in reanalysis data (FreezHGANAL, thick dotted line), and the bright band height (BBH, solid line) for
EOFi-1.0 (the second column) and EOFi+1.0 (the third column). Right-hand panel: Frequency
distribution of the precipitation types for each EOF.

001.HyARC2006-E.indd 24

08.2.1 1:20:27 PM

25Study on algorithms for new-generation space-borne precipitation radar
The Global Precipitation Measurement (GPM) is proposed as the successor to the
Tropical Rainfall Measuring Mission (TRMM). The core GPM satellite will be equippedwith a microwave radiometer (GMI) and a dual-wavelength radar (DPR). The combinationof DPR and GMI data may improve instantaneous precipitation rate retrieval. The main
objective was to improve DPR precipitation retrieval using GMI data. Discussion on thealgorithm development strategy was continued. One of the important results is that the test
data are essential. Several algorithms have already been proposed, but their advantages anddisadvantages have not yet been fully investigated. Extensive test data including many
extreme cases are required to clarify the characteristics of the algorithms. Ground-based
measurement data, such as polarimetric Doppler radar data, wind profiler radar data, anddisdrometer data, should be combined. Non-hydrostatic model results may also be
incorporated.

Atmospheric boundary layer observation over Okinawa Island using a 400-MHz wind profiler radar
It is widely suggested that the south-southwesterly low-level jet (LLJ) is an importantfeature often accompanied with heavy precipitation events during the Baiu season in Japanand Mei-Yu in China. This link implies that a deeper understanding of the LLJ is necessary
for studying Baiu precipitation. Data from UHF wind profiler observations during May–
July over three years (2004–2006) are used to study the atmospheric boundary layer windstructure of the monsoon and the associated LLJ over Okinawa, a subtropical island in the
Northwestern Pacific. Long-term observations of the wind with high temporal and verticalresolutions allowed us to investigate the LLJ statistical characteristics in detail. Hourly
wind profiles are used for analyzing different LLJ categories. The result shows that thestrong LLJ features are significant in the month of June over this island. The frequency of
LLJ occurrence exhibits a diurnal cycle with a maximum in the early morning hours. The
composition of three years of data also reveals that the southwesterly wind regime without
rain has a clearer diurnal variation (Fig. 2). There is a trend of maximum wind propagating
to a higher level in the afternoon hours. Such kinds of variations mostly occurred over a
period of several days with strong surface heating, and the wind kept veering slightly withheight and time.
This observation was conducted as part of a collaborative activity between HyARC and
NICT.

Fig. 2 Wind direction (upper) and wind velocity (lower) observed by a 400-MHz wind profiler radar at
Okinawa Island during an intensive observation period in July 2005. The figure shows the clear diurnal
variation of the wind.

001.HyARC2006-E.indd 25

08.2.1 1:20:29 PM

26Laboratory of Eco-Hydrometeorology
An interception loss experiment in a meteorologically regulated chamberInterception loss (direct evaporation from the forest canopy) is very important toquantify the water budget estimation in a forested basin. The interception loss in forests is
usually estimated from the difference between gross rainfall and net rainfall amounts aboveand below the forest canopy. The forest structure and some meteorological elements would
affect the interception loss. However, it is difficult to reveal quantitatively how and what
factors affect the interception loss in natural forests. Thus, in this study we tried to measure
the interception loss using a regulated meteorological chamber with several experimental
forests composed of young trees. The tree used in this study was boxwood of about 60 cm
in height and about 30 cm in canopy diameter. We changed leaf area index (LAI) by cutting
the branches and leaves and changing the stem density. We set steady meteorologicalconditions in the regulated chamber. We conducted the experiments at the Frozen Snow
Disaster Prevention Experiment Ridge, Shinjo Branch, Snow and Ice Research Center,
National Research Institute for Earth Science and Disaster Prevention. Figure 1 shows anexample of experimental scenery, and Fig. 2 indicates arrangements of the experimental
forests.
The meteorological settings were as follows: rainfall duration two hours, rainfall
intensity 5.5 mm hr−1, wind speed 0.5 m s−1, air temperature 20 °C, and relative humidity
90%. After starting every experiment, the air temperature always decreased around 2 °C,
and the relative humidity increased around 10%.
The relationships between interception rate and LAI or the stem density are shown in
Figs. 3 and 4, respectively. Here the interception rate was estimated from the net rainfall
amount above the forest canopy and the gross rainfall amount. It was shown that theinterception rate increased with LAI regardless of the stem density (Fig. 3). On the other
hand, clear relationships were not obtained between the stem density and the interception
rate (Fig. 4).

LAI 0.3

LAI 1.2
LAI 2.1
LAI 3.1(a) Images of the branches with different LAI

4.0 stem m–2 7.1 stem m–2
11.1 stem m–2 14.4 stem m–2(b) Images of the forests with different stem density
Fig. 1   Experimental scenery.

Fig. 2   Schematics of the experimental forests.
0.4
Interception rate

Interception rate

0.4
0.2
0
4.0 stem m–2-0.2

7.1 stem m–2
11.0stem m–2-0.4
014.4 stem m–2

1

2
3
Leaf Area Index

0
-0.2
-0.4

4

Fig. 3 Relationship between LAI and interception
rate.

001.HyARC2006-E.indd 26

0.2

0

LAI 0.3
LAI 1.2
LAI 2.1
LAI 3.1

3
6
9
12
Stem density (stem m–2)

15

Fig. 4 Relationship between stem density andinterception rate.

08.2.1 1:20:30 PM

27Characteristics of atmospheric turbulence spectrum above the forest canopy under stable conditions
Because forests have large roughness to the atmospheric flow, the roughness sublayer(RSL) is formed above the ground up to 2–3 times higher than the mean tree height (h).
Turbulence structure in the RSL tends to be different from that in the atmospheric surface
layer (ASL). Although understanding the turbulence structure under various conditions isessential for accurate estimation of the exchange of momentum, heat, and mass between
forests and the atmosphere, the knowledge under stable conditions is not well known.
Thus, this study investigated the turbulence spectrum under stable conditions using 10 Hzdata obtained by ultrasonic anemometer thermometers (Solent R3 ; Gill Inst., Ltd., UK),
which were installed two heights above a larch forest growing on flat terrain (42°44’N, 141°
31’E; Tomakomai Flux Research Site managed by National Institute for Environmental
Studies). The observation was conducted from June to October in 2002, and data for thisanalysis were selected to satisfy a 30-minute stationarity. To reduce random spectrum
errors, ensemble averaging was done after classifying all 30-minute spectra by atmosphericstability (z ).
Figure 5 shows velocity and temperature spectra and momentum and sensible heatcospectra obtained at two heights above the canopy under stable conditions. For every
variable, the spectrum exhibited a sharper peak compared to the ASL spectrum obtained
from previous studies. Furthermore, the peak shifted toward lower frequencies, with a few
exceptions of momentum cospectrum under weakly stable conditions. These findings
revealed the existence of large coherent eddies initiated by wind shear around the canopy
even under stable conditions, though it was usually observed under near-neutral conditions.
Such spectral characteristics were conspicuous in streamwise wind velocity andtemperature spectrum. Because their peak frequencies were observed at lower frequencies
than that of vertical wind velocity, representing fluctuations attributed to wind shear near
the surface (active motion), it was suggested that they were affected by fluctuations
attributed to the large atmospheric field over the forest (inactive motion). Furthermore, thesimilar peak shape and frequencies in momentum and sensible heat cospectra to those of
streamwise wind velocity and temperature spectra suggest that the inactive motion
accounts for vertical transfer above the forest canopy to some extent.
The observed spectra of all variables showed the tendency to approach the ASL spectrawith increasing stability. Especially for the spectra of vertical and lateral wind velocity andthe cospectra of momentum and sensible heat flux observed at the upper level, the second
peak appeared at frequencies close to the peak frequency of the ASL spectrum. The
existence of double peaks must indicate that RSL turbulence consists of coherent eddies
and ASL turbulence. The results suggest that RSL height decreased with increasingstability, and consequently the effect of ASL turbulence was relatively intensified.
Challenges for the future are to investigate the RSL spectrum for the general applicability of the stability dependence obtainedby this study. The relationship between thepeak frequency of the RSL spectrum and surface parameters, such as mean tree heightand vegetation density, should also be studied.

Fig. 5 Longitudinal axis represents normalized frequency f (= n z/U; n: frequency, z: measurement height, U:
mean wind speed) and vertical axis shows frequency-weighted power spectra and cospectra
normalized by variance or covariance (u: streamwise wind velocity, v: lateral wind velocity, w: verticalwind velocity, t: temperature, uw: momentum flux, wt: sensible heat flux). Data were obtained at 1.7 h(open circles) and at 1.2 h (crosses). Appended solid lines represent the empirical models for the ASL
spectra. The alphabets above the figure indicate the category of ζ (a: 0.02–0.04, b: 0.08–0.1, c: 0.15–
0.2, d: 0.4–0.5, e: 0.8–1).

001.HyARC2006-E.indd 27

08.2.1 1:20:32 PM

28Laboratory of Ocean Climate Biology
The climate system surrounding us is governed by cycles of water and materials in thehydrosphere and atmosphere on Earth. In this laboratory, we study the inter-relationshipbetween climate change and ocean biogeochemistry on time scales ranging from a decade
to a century. Brief description of our laboratory activities follows.
l Ocean Primary Production Monitoring by Satellites

Primary production is one of the key processes in understanding the relationshipbetween climate change and ocean biogeochemistry. A global view of the primary produc­tion can be attained by satellite remote sensing, but the quantitative estimation of primary
production is still hindered by the lack of in situ data to validate the satellite observations.
To fill this gap, we developed an underwater profiling buoy system and a custom made fast
repetition rate fluorometer (FRRF), and constructed an ocean primary productivity
profiling system. This work was done as a part of the Core Research for Evolutional Scienceand Technology (CREST) program 1999-2004. Currently, we are developing a pilot system
to monitor oceanic primary production by combining the productivity profiling system inoperation with supporting data handling systems to merge satellite and in situ data. This
work is being conducted under a new 5-year continuation project as part of Solution
Oriented Research for Science and Technology (SORST) program, started in 2004. The goalof the project is to design a practical system to monitor the global ocean primary
production. The immediate tasks are to validate the satellite primary production data, andto demonstrate the usefulness of the validated satellite data for studies of the temporal andspatial variations of ocean biogeochemistry in response to the physical forcing functions at
the surface ocean. [In this text, the term “primary productivity” is used for rate of “primary
production” in time scale of an hour or a second. The term “primary production” is usedconventionally for the “primary productivity” in time scales of a day or a year.]

Operation of ocean productivity profiling system in the western subarctic North Pacific
The underwater profiling buoy system developed in collaboration with Nichiyu-Giken
Co. Ltd. is composed of an underwater winch system and a profiling buoy system. The
profiling buoy is equipped with sensors and normally stays below the euphotic zone.
Profiling measurements are done in the upper layers from the winch depth to the surface
according to a preset schedule. We installed a custom made FRRF (KIMOTO Electric Co.
Ltd.) as a main sensor, in which the data processing is conducted in real time during the
profiling measurements. All the measurement data are stored and a part of the processeddata is transmitted to the laboratory via cellular phone before the buoy sinks back to theresting position.
During the period from June 9 to July 15 2006, we deployed the ocean productivity
profiling system at a station in the western subarctic North Pacific (47°50’N, 160°00’E: 5115m
of depth). That was the first offshore mooring in deep water. Out of 39 scheduled operations,
34 profiles were obtained successfully with 22 completed real time data transmissions. Data
collected from the system are shown in Fig. 1. In late June, both the chlorophyll a con­centrations (Chl a) and gross primary productivity (GPPc) dropped (Fig. 1b, c), probably
because of the intrusion of different (other) water masses. On the other hand, the biomass
specific gross productivity (GPbc) increased (Fig. 1d). In the same period, dissolved oxygen
remained oversaturated and acoustic backscattering strength data of ADCP showed anincrease in large particles that did not contain chlorophyll a within the upper layer. These
data implied that grazing pressure of zooplankton on phytoplankton was probably a principal
controlling factor of primary productivity. This is the first-ever in situ measure­ments of the
open-ocean productivity in such high time resolution, demonstrating the utility of themonitoring system in further understanding the natural variability of ocean productivity.

001.HyARC2006-E.indd 28

08.2.1 1:20:33 PM

29Fig. 1. Time series data transmitted from the monitoring system in the western subarctic
north Pacific from June to July 2006. (a) Temperature, (b) Chl a, (c) gross primary
productivity (GPPc), (d) Chlorophyll a specific gross productivity (GPbc), and (d)dissolved oxygen saturation (%).

Estimation of oceanic daily depth-integrated primary production from FRR fluorometry
Φe (molecules electron–1)

FRRF based PBO2(mmolO2 mmolchl a–1 h–1)

In the operation phase, the ocean produc­abtivity profiling system conducts a few FRRF
measurements per day, which provide depthprofile data of instantaneous chlorophyll a
specific primary productivity (PBO2). In orderto validate satellite derived production, daily
Underwater PAR (µE m s )σ (X10 m photon )depth-integrated production (mgC m –2 d –1)
needs to be estimated. In this study, we con­
1 :1cdstructed an algorithm to estimate daily depthintegrated production from a single FRRF
observation, using a database obtained from
intensive FRRF measurements in the Sagami
Bay from 2003 to 2006. This analysis reveals
that FRRF-based hourly PBO2 is mainly con­
Measured productivity
Underwater PAR (µE m s )(mmolO m d )trolled by σ PSII (effective absorption crossFig. 2. Relationship between (a) underwater PAR
section of PS II for phytoplankton) (Fig. 2b)and Φ e , (b) P B O2 and σ PSII , (c) P B O2 andat a high irradiance level where Φe (quantum
underwater PAR, and (d) comparison ofyield of electron transfer for O 2 evolution)
daily depth-integrated production between
intensive FRRF measurements and algo­
was below the theoretical maximum, 0.25
rithm-derived estimates in Sagami Bay.
(Fig. 2a). Using the midday FRRF data, we
determined a threshold of underwater-PAR(E Φe ) where Φ e <0.25, and derived distinct empirical relationships for two cases ofunderwater PAR (E) level. For E>E Φe, the E-σ PSII , and σ PSII -P B O2 relationships areincorporated into the new algorithm, and for E<EΦe, the E-PBO2 relationship (Fig. 2c) isused. By applying the estimated time series profile of E to the empirical relationships, we
calculated the time series profile of PBO2. Finally, the profile was multiplied by the Chl a andintegrated over depth and time, to estimate daily depth-integrated production (mmolO2 m–2
d –1 ) was estimated. The algorithm-derived production showed good agreement withmeasured ones (Fig. 2d), and thus the estimation of near-surface production was greatly
improved.
y = 0.04 x+ 0.13 r2 = 0.91,
n=7037, p <0.01

n=778, p<0.01

PSII

–20

–2 –1

2

001.HyARC2006-E.indd 29

2–1

Estimated productivity(mmolO2 m–2 d–1)

FRRF based PBO2(mmolO2 mmolchl a–1 h–1)

–2 –1

y = 0.024 x – 1.02 r2 = 0.78,–2 –1

08.2.1 1:20:43 PM

30
Plankton metabolic balance in the upper ocean
When we consider the functionalrole of an ocean ecosystem, it iscritical to determine the spatial vari­ability in the net metabolic status
and the balance between grossproduction and community respira­tion in a given oceanic eco­systems,
because it would dictate whether
oceanic regions are net sources or
net sinks of CO2 to the atmosphere. Fig. 3. Spatial distribution of (a) GPP and (b) NCP/GPP ratios
In this study, we measured the timein Sagami Bay during May 2006.
(7-10 days) and depth integrated
plankton metabolic rates of gross primary production (GPP), net community production(NCP) and community respiration (CR) using triple oxygen isotopes and O2/Ar ratios with
our recently developed high-resolution spatial underway sampling technique, in Sagami
Bay during May 2006. The estimated GPP varied from 34 to 963 mmolO 2 m–2 d–1 in themixed layer and higher production rates were observed in the eutrophic coastal regions
around the head of a bay (Fig. 3a). The NCP/GPP ratios in the Sagami Bay varied from –0.5
to 0.3. The higher ratios were observed in the southeastern Bay (0.17 to 0.3) and the lowest
ratios in the southwestern Bay (–0.49 to 0.09), whereas they were between 0.07 and 0.26 in
the rest of Sagami Bay (Fig. 3b). The negative NCP/GPP ratios in the southwestern open sea
region indicate that community respiration was dominant over the production during thestudy period. Our study suggested that coastal regions showed strong autotrophy whereas
heterotrophy was observed in the offshore regions: also as a whole, plankton production isslightly in excess of community respiration. This excess carbon can support the export ofcarbon to the oceans’ twilight zone.

Seasonal and diel variations in heterotrophic bacterial community in Sagami Bay, Japan

001.HyARC2006-E.indd 30

80
60

200

24th April

160

40
120

20

30

2000

1600

1200

0800

0400

80

50
40
30
20
10
0

18th June

20
10

30

2000

1600

1200

0800

0
0400

Bacterial abundance (x 1011 cells m-2)

0

50
40
30
20
10
0

1st August

20
10

1200
1500
1600
2000

0800

0
0400

Chlorophyll a (mg m-2)

Bacteria utilize dissolved organic carbon (DOC), incor­
porate it into particulate biomass, and thereby help mediate
cycling of nutrients and materials in seawater. For con­struct­ing a model of oceanic net metabolic balance, it isimportant to understand mechanisms regulating theabundance of heterotrophic bacterioplankton. In this study,
natural populations of bacteria were sampled from Sagami
Bay in April, June, and August 2004, stained with DNAspecific fluorochrome SYBR Green I, and analyzed by flow
cytometry. The mixed layer temperature progressively
increased through the study period from 17°C in April to
27°C in August whereas the salinity decreased from 34 to
33 exhibiting the onset of stratification from April. The Chl
a was highest in April followed by June and August. The
bacterial population showed a similar seasonality, indicat­
ing that it is primarily controlled by the supply of DOC via
phytoplankton’s photosynthesis. Also positive correlations
were significant between diel changes in bacterial
abundance and Chl a during each study period (Fig. 4). In
June, however, the bacterial abundance was occasionally
low despite the high Chl a, which is probably due to grazingby bacterivores.

Sampling time (h)Fig. 4. Diel variations in bacterial
abundance and Chl a in
S a g a m i B ay d u r i n g t h estudy periods.

08.2.1 1:20:45 PM

31Effect of biofilms on the performance of fast repetition rate fluorometer (FRRF)
Benchtop mode
20

F0

16

ControlWith biofilm

12
8
4
0
20

Fm

16

ControlWith biofilm

12
8
4
0
8

Fv

6

ControlWith biofilm

4
2
0

Fv/Fm

0.6
0.4
0.2
0

σ PSII (Å2quanta-1)

As with any substratum immersed in seawater, sensors are
susceptible to “Biofouling” which is caused by the adhesion of
micro- and macro-organisms, and can diminish sensor
operation and performance. To achieve long-term monitoring ofocean primary production using the ocean productivity profil­ing system, the biofouling effect on FRRF data during deploy­ment should be determined. Here, we examined the effect of
biofouling on the performance of FRRF (Chelsea Instruments
Co. Ltd.) with simulation experiments in which measurements
were made by placing fouled coupons of different levels of
biofilm transmission and Chl a on the FRRF excitation anddetection windows. Our results showed that the biofilms
dominated by chlorophyll a containing organisms on thedetection window affected the quality of fluorescence data; theF 0 and F m values increased and the potential photochemicalquantum yield of PSII (Fv/Fm) decreased accordingly (Fig. 5).
This is because the detection window received fluorescencesignals not only from the sample algae but also from thechlorophyll a in the biofilm, which was excited using an LED
flashlight. It was observed that Chl a greater than 0.3 mg cm–2
in the biofilm on the detection window would critically affectfluorescence measurements. On the excitation window, thebiofilm reduced the flash intensity; this also affects the data
quality only if transmission is significantly reduced. Theseobservations suggest that the fluorescence data would be
disturbed by biofouling on the optical windows, especially withthe case of biofilm containing chlorophyll a on the detection
window. However, with the biofouling effect quantified in thisstudy and the measurement of Chl a on the detection window it
is possible to correct the FRRF data if the flash intensity
remains nearly constant during deployment.

600
450

ControlWith biofilm

ControlWith biofilm

300
150
0
100 99 98 97 96 95 94 93 92

Transmission (%)

Fig. 5. Effects of natural bio­films (placed on bothof the FRRF optical
windows) on FRRF
measurements madein bench top mode.
Note: Units of F0, Fm,
F v   and  F v / F m   aredimen­sionless.

Diel variations in photo-physiological state of phytoplankton assemblages in the upper Gulfof Thailand
In coastal seas relatively high primary production occurs because of the supply of landdriven nutrients, accounting for about 1/5 to 1/3 of the global ocean production. The coastal
primary productivity has large variability, both in time and space, in response to changes inenvironmental conditions caused by tidal movements, river inflow, and human activities. In
this study, we conducted intensive FRRF observations (2 hr interval from 8:00 to 18:00) in
the upper Gulf of Thailand (UGOT) in July 2006, to evaluate a diurnal change in the photophysiological state of natural phytoplankton assemblages. Here, we report the result of
FRRF-based photosynthetic parameters, the potential photochemical quantum yield of PSII
(FV/FM), and the effective absorption cross-section of PSII (σPSII), obtained from the eastern
and western sites of the UGOT (Stn. 1 and Stn. 5, respectively). At Stn. 1 where the salinity
stratification had developed because of river inflow, σPSII and FV/FM range from 340 to 820

001.HyARC2006-E.indd 31

08.2.1 1:20:46 PM

32

0

0

-1

-1

Depth (m)Depth (m)Å2 photon–1 and from 0.4 to 0.6, respectively. In the well-mixed waters of Stn. 5, they range
from 480 to 900 Å 2 photon –1 and from 0.2 to 0.6 (Fig. 6). A significant decay of σ PSII
observed in the upper layer during the day is correlated with underwater PAR increase,indicating that phytoplankton get acclimated to high light condition (Photo acclimation) by
reducing their light harvesting ability to circumvent photo-damage. On the other hand, anegative correlation of F V /F M to PAR is found in Stn. 5, indicating that parts of thephotosynthetic unit of phytoplankton would be damaged by high light (photo-inhibition).
This is probably because in Stn. 5, the low-light adapted phytoplankton were dominantbecause vertical mixing causes exposure to a broad range of light levels.

-2
-3

-2
-3

-4

-4

-5

-5

-6
08:00

10:00

12:00

-7

14:00
Time

16:00

18:00

-6
08:00
-7

10:00

12:00

14:00

16:00

18:00

Time

-8 photochemical quantum yield of PSII (FV/
Fig. -86 Diel variations in under water PAR and the potential
F
)
in
the
western
site
(Stn.
5)
of
the
upper
Gulf
of
Thailand.
M-9-9l Studies on changes in the biogeochemical cycle in oceans with reference toclimate change

Estimation of gas exchange coefficient (piston velocity) using stable oxygen isotopes
The accurate estimation of the transfer of tracegases across an air-water interface is required tounderstand the ocean-atmosphere coupling of thebiogeochemical cycle in the earth system. Althougha variety of different parameterizations were pro­
posed to calculate the gas exchange coefficient (K)using different models and different tracers, the useof these parameterizations led to K values that
could differ by a factor greater than2. Accordingly,
these estimates have large uncertainties (~30%)
resulting in large errors in the flux estimates. We
estimated K by a novel method using triple oxygenisotopes in dissolved O2. This method relies on an
observed isotopic anomaly for molecular oxygen in Fig. 7. Wind speed versus piston velocity
seawater. The ∆ 17O anomaly in the mixed layer isof oxygen – comparison of the ∆17 O anomaly model with othercontrolled by gross oxygen production (GOP) andmodels.
influx of O2 from the atmosphere. In this study, we
17measured changes in the ∆ O anomaly in the western subarctic North Pacific during nighttime, when no GOP occurs, at every 2 hr interval for four nights during July to August in
2006. The piston velocity derived from the ∆17O anomaly was consistently higher at lower
wind speeds and similar at higher wind speeds compared with that of Wanninkhof and
McGills (1999) (Fig. 7). Relative to other methods, the present method is more robust andgives a K value in the semi-diurnal scale with reduced errors. Therefore, it is possible toestimate daily variations in K using this method, leading to a more precise estimation of
air-sea flux of carbon.

001.HyARC2006-E.indd 32

08.2.1 1:20:49 PM

33
Impact of the bi-weekly tidal variations on Chl a in the northwestern Okhotsk Sea, central
Kuril, and Aleutian Islands areas-2-1ln(Chl) (PAR=30 E m day )In the subarctic North Pacific, the high Chl a (B) -0.4
mid-August-September
for the post-spring bloom period (late summer) are-0.6
2002-2005
commonly confined to dynamically active zones-0.8(straits, banks, etc.), where nutrients are supplied-1.0
to the euphotic layer. Because of the superpositionof K1 and O1 tides, the tidal current speeds in the-1.2
northern Okhotsk Sea, Kuril, and Aleutian Islands-1.4
47-48 0 N, 131.5-133.5 0 E
regions are undergo significant bi-weekly varia­-1.6
tions. Using satellite-derived Chl a, PAR, and sea
0
30
60
90
120
surface temperature data, we have examined the33
Tidal Amplitude (0.001, cm )temporal variability in Chl a in response to bi–2
weekly tidal variability. Our results show that tem­ Fig. 8. Log–1Chl a (adjusted to PAR=30 E mday ) versus tidal amplitude in Kuril
poral changes in the spatially averaged Chl a in the
Islands area.
surface waters of central Kuril and AleutianIslands regions are induced by quasi-periodic (period of 6-9 days) variability in PAR, biweekly variability in tides (Fig. 8), and water exchange between the inshore and offshore
areas forced by anticyclonic eddies. In the northwestern Okhotsk Sea (Kashevarova Bank
region), the enhanced tidal mixing increases Chl a during high PAR and high phytoplankton
biomass period and reduces Chl a during low PAR and low phytoplankton biomass period.
For the Kuril Islands area, we observed an increase of the spatially averaged Chl a in thesurface waters during moderate tides (Fig. 8). It can be related with an increase of thephytoplankton growth in the surface waters due to nutrient and biomass supply from thesubsurface (the Chl a maximum layer) to surface layers. During strong tides the Chl a wassignificantly reduced (Fig. 8), probably because the average light energy available tophytoplankton cells was reduced, and the tides resulted in increased phytoplankton losses
because cells were removed from the surface layer.

Chl a response to autumn wind events in the coastal northern Japan Sea

001.HyARC2006-E.indd 33

1.0

1997-2006; 42.25-75 0N, 132-133 0E

0.6
ln(Chl)The northern Japan Sea has many characteristics
of subarctic waters, with large seasonal variability
reinforced by a monsoon climate. In the coastal
waters, northwest wind-driven upwelling supplies
abundant nutrients to be processed by phytoplankton
production in autumn. To understand such winddriven effects on the primary production, we analyzed
satellite Chl a, sea surface temperature (SST), and PAR
data collected between 1997 and 2006. In the study
area (Fig. 9a), the Chl a increased from ~0.8 µg L–1 inSeptember to ~2.0 µg L–1 in November while daily PAR
decreased from ~35 E m–2 to ~17 E m–2. The spots ofhigh Chl a were related to upwelled waters identified
by low SST. Our results show a strong correlation
between Chl a and strength of the wind induced
upwelling in the coastal area (Fig. 9b). Enhanced
upwelling leads to a shallower pycnocline layer(characterized by high nutrients and seed stocks ofphytoplankton cells) and thus promotes photo­
synthesis in the sea surface as phytoplankton responds
to high light and nutrients.

0.2
-0.2
November-0.6

October

-1.0
0.5

1.5

2.5

3.5

4.5

ZonalWind, m/s

Fig. 9. (a) Study area and wind stressvector (November 1997-2006),(b) Log Chl a vs. zonal wind.

08.2.1 1:20:51 PM

34
Spatial distribution of δ15N of suspended particles in the surface waters of Sagami Bay
The downward transport of carbon via the “biological”
pump plays a major role in the CO2 sequestration to deep
oceans. In general, the biological pump is expected to beenhanced in highly productive periods (such as spring
blooms); however, the regulating mechanisms of thebiological pump efficiency remain unclear. Here, we
examined spatial variations in δ 15 N of the sea surface
suspended particles (δ15Nsus) in Sagami Bay during May
2006 to understand the properties of nutrients drawdown
resulting from phytoplankton production during winter tospring transition. The δ15Nsus ranged from 4.6 to 8.9 per
mil and correlated negatively with the silicate to phos­ Fig. 10. R e l a t i o n s h i p b e t w e e nmixed layer averaged Si/P
phate (Si/P) ratios of dissolved nutrients concentra­tions
and d 15 N sus of suspended(Fig. 10). This implies higher contribution of diatom toparticles in the surface
the integrated nutrients drawdown (fDiatom) in the regions
waters of Sagami Bay inwhere the efficiency of nutrient consumption by phyto­
May 2006.
plankton (= consumption/nutrient supply; U) is high. The
15
analysis of δ N sus with a simple Rayleigh Distillation
equation demonstrates positive relationships of f Diatom (0.2-0.7) to U (0.4-0.7), and theintegrated phosphate drawdown (0.14-0.42 µmolP L –1 ). These results emphasize asignificance of the diatom group in the nutrients drawdown, and thereby emphasize thebiological pump efficiency during produc­tive seasons in Sagami Bay.

Particle dynamics in the subsurface Sagami Bay‰
Organic matter produced in the euphotic zone ofoceans sinks down to deeper layer as particles. They are
Smaller sinking particles
consumed by organisms and decomposed via biological(<20µm)processes in the water column. Although the biological◯ Suspended
particles
activities are relatively higher in the near surface layers,
little is known about the particle dynamics such as produc­tion, transformation, and decomposition in and/or duringtransport out of the upper oceans. In this study, we
examine the vertical changes in 13C and 15N characteristics
of suspended and sinking particles in the upper water
Total sinking particles
column of Sagami Bay to articulate the processes in
Larger sinking particles(>20µm)particle dynamics within the surface-subsurface layer. The
sinking particles were collected by a set of multilayer traps
Fig. 11. Vertical profiles for the d13C
at 20-140m (7 layers, 20 m intervals), moored at the centralof suspended and sinking
part of the Bay from May 2 to 9, 2006. Trapped materials
particles collected at thewere separated into two fractions, one the “small sinking
upper layer of the Sagami
particles” (<20 µm), and the other “large sinking particles”
Bay during May 2006.
(>20 µm). Isotopic measurements were made for eachfraction. Our result reveals that almost all the sinking particles consist of “large sinking
particles” which showed little variation in δ13C, δ15N, and C/N ratios with increasing depth(Fig. 11). These properties are similar to that of suspended particles at 20 m; this implies
that the larger sinking particles are composed of phytoplankton themselves and receive little
alteration during sinking from euphotic to the 140 m layer. The smaller sinking particles
show contrasting properties in isotopic values and C/N ratios, compared with the larger ones
(Fig. 11). Judging from those signals, the smaller particles are composed of highly degradedorganic matter. Though they are trapped in the trap cylinder, they are too small to sinkindependently; hence it is thought that the smaller sinking particles sink in association withthe larger sinking particles. In addition, the suspended particles below the euphotic zone
show similar properties with those of smaller sinking particles, indicating that the major
source of suspended particles is the smaller sinking particles.

001.HyARC2006-E.indd 34

08.2.1 1:20:53 PM

35Laboratory of Bio-Physical Oceanography
Observation of material transport through the eastern channel of the Tsushima/Korea Strait
Enormous fresh water and materials are transported from the East China Sea (ECS) to
the Japan Sea (JS). Isobe et al. (2002) reported that at least 70% of fresh water in the ECS
enters into the JS through the Tsushima Korea Strait (TKS). Therefore, the change of
Changjiang river discharge due to the Three Gorges Dam strongly influences the ocean
environment not only in the ESC but also in the JS. Although it is certain that the change ofriver discharge will impact both the ECS and the JS ocean environment, it has not been
revealed yet how degree influences the environmental change and how much materials aretransported through the TKS. Hence, it is very important for predicting the future environ­ment of the JS to evaluate quantitatively the energy and material transport through theTKS. In the present study, we conducted field observations at two lines where the volumetransport of the Tsushima Warm Current can be estimated, and heat, fresh water,
chlorophyll, and nutrient transports by the Tsushima Warm Current were evaluated.
Field observations were conducted 15 times
at CL and N lines by mainly T/V Tenyo of
National Fisheries University as shown in Fig.
1. Since tidal current is dominant in the TKS,
average material transports cannot be eva­
luated by instantaneous current velocity datameasured by ADCP. Therefore, it is necessarythat tidal signals are removed from ADCP datain order to estimate average material trans­
ports. The harmonic constants of tidal currents
have been estimated from long-term shipmounted ADCP measurements at CL line
(Takikawa et al., 2003) and from moored ADCP
measurements at N line (Teague et al., 2001). It
is possible that we can eliminate tidal signals
Fig. 1   Observation lines in the TKS.
from the instantaneous ADCP data at the twolines and see the vertical structure of the Tsushima Warm Current. At each observation
station, we measured water temperature, salinity, chlorophyll a, DO and nutrients by CTD
and water sample.
Material flux and transports through CL and N lines are evaluated from multiplying thecurrent velocity by each component such as water temperature, chlorophyll a, andnutrients. Fresh water flux in the upper layer is large owing to reflecting salinity
distribution, and maximum fresh water flux appears as well in the central part of theeastern channel where current velocity is the fastest. As for the nutrient flux, maximum flux
appears in the middle layer of the eastern channel because nutrient concentration increases
from surface to bottom while current velocity decreases. A cyclonic eddy appears frequently
in the eastern channel in summer. Nutrient flux near the cyclonic eddy increases bysupplying nutrient from the bottom layer associated with upwelling. Mean volumetransport across the CL line from August 2005 to November 2006 is 0.91 (Sv). That value isconsistent with the result of Takikawa et al. (2005). However, the volume transport on 19
August 2005 is extremely small, 0.16 (Sv), due to counter currents in the surface layer
vicinity of Tsushima Island and in the bottom layer vicinity Kyushu. Fresh water transport
is highest in summer and then gradually decreases to its lowest in April. Average fresh
water transport across the CL line is 21.50 × 106 (kg/s). DIN (Nitrate + Nitrite) transport islarger in summer and autumn and lower in winter and spring. Mean DIN transport acrossthe CL line is 2.76 (kmol/s) and that within the euphotic zone (50 m) is 0.92 (kmol/s).
Considering that DIN transport from the Changjiang river is 2.1 (kmol/s) (Zhang 1996), it issuggested that the horizontal transport of DIN by the Tsushima Warm Current plays animportant role for the lower trophic ecosystem in the entrance of the JS.

001.HyARC2006-E.indd 35

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36
Summertime decrease in water temperature at subsurface layer in Sagami Bay
The frequent occurrence of the summertime decrease in water temperature at thesubsurface layer in Sagami Bay is revealed by analysis of monthly CTD data at station S3(35°00’N, 139°20’E) from January 1997 to July 2004 and historical oceanographic data from1970 to 2001 (MIRC Ocean Dataset 2005). The intensity and area coverage of the decreasein water temperature change from year to year and vary with depth (Fig. 2a). The depth
where this phenomenon occurred is from 20 m to deeper 200 m. Average magnitudes of thedecrease in water temperature reach a maximum at depth of around 50 to 100 m anddecrease to the surface and deeper layers, while its area coverage is considerably large andmay occupy the whole Bay in some cases. The time scale of this phenomenon has not been
known yet because all observations are limited to only one or several days a month, but
results from CTD and historical oceanographic data reveal that there are some cases withperiods longer than one month. This phenomenon plays an important role in the biologicalprocesses in Sagami Bay through increasing nutrient and chlorophyll a concentration at
the near-surface layer. Although the relationships between the summertime decrease inwater temperature and distance to the Kuroshio path from S3 station and between thisphenomenon and distance of the Kuroshio path displacement are not highly correlated.
However, the Bulletin of Ocean Conditions and other evidence demonstrate that all these
events may relate to the appearance and displacement of the cold water mass (or cold eddy)
off Enshu-nada under influences of the Kuroshio path variation. This hypothesis is also
confirmed by analyzing a numerical model result of Guo et al. (2003) (Fig. 2b). The frequent
occurrences of cold eddies as well as their displacement along the Japan coast
accompanying the Kuroshio path meander are possibly the main reason for thesummertime decrease in water temperature at the subsurface layer in Sagami Bay (Fig. 3).
a)b)Fig. 2   Time-Depth plot of CTD (a) and Model (b) temperature at station S3 in Sagami Bay.
a)b)

Fig. 3   Sea surface elevation anomaly in summer 1995.

001.HyARC2006-E.indd 36

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37

List of Publications* : Staffs, students and research fellows in the HyARC.
01.

02.

03.

04.

05.

06.

07.

08.

09.

10.

11.

12.

13.

14.

15.

16.

002.HyARC2006-Pub.indd 37

Bhatt, B.C.* and K. Nakamura*A climatological-dynamical analysis associated with precipitation around the southern part of
the Himalayas. Journal of Geophysical Research, vol.111, D02115, doi:10.1029/2005JD006197,
2006.
Chiba, S., K. Tadokoro, H. Sugisaki and T. Saino*
Effects of decadal climate change on zooplankton over the last 50 Years in the western
subarctic North Pacfic. Global Change Biology, Vol.12, No.5, 907-920, doi:10.1111/j.13652486.2006.01136.x, 2006.
Endo, N. and T. Yasunari*
Changes in Low Cloudiness over China between 1971–1996. Journal of Climate, 17-9,
1204-1213, 2006.
Endo, N., T. Kadota, J. Matsumoto, B. Ailikun and T. Yasunari*
Climatology and Trends in Summer Precipitation Characteristics in Mongolia for the Period
1960–98. Journal of Meteorological Society of Japan, 84-3, 543-551, 2006.
Fujita, K., L.G. Thompson, Y. Kajikawa, Y. Ageta, T. Yasunari*, A. Sakai and N. Takeuchi
Thirty-year history of glacier melting in the Nepal Himalayas. Journal of Geophysical Research,
Vol.111, 2006.
Goswami, B.N., G.X. Wu and T. Yasunari*
The Annual Cycle, Intraseasonal Oscillation and Roadblock to Seasonal Predictability of the
Asian Summer Monsoon. Journal of Climate, 19-20, 5087-5099, 2006.
Ichikawa, H.* and T. Yasunari*Time-space Characteristics of Diurnal Rainfall over Borneo and Surrounding Oceans as
Observed by TRMM-PR. Journal of Climate, 19-7, 1238-1260, 2006.
Kummerow, C., W. Berg, J. Thomas-Stahle and H. Masunaga*
Quantifying Global Uncertainties in a Simple Microwave Rainfall Algorithm. J. Atmos. Oceanic
Tech., 23, 23-37, 2006.
L’Ecuyer, T.S., H. Masunaga* and C.D. Kummerow
Variability in the Characteristics of Precipitation Systems in the Tropical Pacific. Part II.
Implications for Atmospheric Heating. J. Climate, 19, 1388-1406, 2006.
Liu, A.Q., G.W.K. Moore, K. Tsuboki* and I.A. Renfrew
The effect of the sea-ice zone on the development of boundary-layer roll clouds during cold air
outbreaks. Boundary-Layer Meteorology, doi:10.1007/s10546-005-6434-4, 2006.
Liu, Y.*, T. Hiyama*, R. Kimura and Y. Yamaguchi
Temporal influences on Landsat-5 Thematic Mapper image in visible band. International
Journal of Remote Sensing, 27, 3183-3201, 2006.
Liu, Y.*, T. Hiyama* and Y. Yamaguchi
Scaling of land surface temperature using satellite data: A case examination on ASTER and
MODIS products over a heterogeneous terrain area. Remote Sensing of Environ­ment, 105,
115-128, 2006.
Maesaka, T., G.W.K. Moore, A.Q. Liu and K. Tsuboki*
A simulation of a lake effect snowstorm with a cloud resolving numerical model. Geo­phy­sicalResearch Letters, Vol.33, L20813, 2006.
Masunaga, H.* and C.D. Kummerow
Observations of Tropical Precipitating Clouds Ranging from Shallow to Deep Convective
Systems. Geophys. Res. Lett., 33, L16805, doi:10.1029/2006GL026547, 2006.
Masunaga, H.*, T.S. L’Ecuyer and C.D. Kummerow
The Madden-Julian Oscillation Recorded in Early Observations from the Tropical Rainfall
Measuring Mission (TRMM). J. Atmos. Sci., 63, 2777-2794, 2006.
Matsui, T., H. Masunaga*, R.A. Pielke Sr., S.M. Kreidenweis, W.-K. Tao, M. Chin and Y.J.
KaufmanSatellite-based Assessment of Marine Low Cloud Variability Associated with Aerosol,
Atmospheric Stability, and the Diurnal Cycles. J. Geophys. Res., 111, D17204, doi:10.1029/
2005JD006097, 2006.

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38
17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

002.HyARC2006-Pub.indd 38

Moteki, Q., T. Shinoda*, S. Shimizu, S. Maeda*, H. Minda*, K. Tsuboki* and H. Uyeda*
Multiple Frontal Structures in the Baiu Frontal Zone Observed by Aircraft on 27 June 2004.
SOLA (Scientific Online Letters on the Atmosphere), 2006, Vol.2, 132-135, doi:10. 2151/
sola.2006-034, 2006.
Naqvi, S.W.A., H. Naik, A. Pratihary, W.D. Souza, P.V. Narvekar, D.A. Jayakumar, A.H. Devol, T.
Yoshinari and T. Saino*
Coastal versus open-ocean denitrification in the Arabian Sea. Biogeosciences Discus­sions, 3,665-695, 2006.
Sano, T.* and K. Tsuboki*
Structure and Evolution of a Cumulonimbus Cloud Developed over a Mountain Slope with the
Arrival of Sea Breeze in Summer. Journal of the Meteorological Society of Japan, 84(4), 613-640,
2006.
Saito K., T. Yasunari* and K. Takata
Relative Roles of Large-scale Orograghy and Land surface processes on Global Hydro-climate.
Part II. Impacts on Hydro-climate over the Eurasian Continent. Journal of Hydro­meteorology, 7,642-659, 2006.
Sakai S., R. Harrison, K. Momose, K. Kuraji, T. Yasunari*, L. Chong and T. Nakashizuka
Irregular Draughts Trigger Mass Flowering in a Seasonal Tropical Forests in Asia. American
Journal of Botany, 93(8), 1134-1139, 2006.
Sarma, V.V.S.S.*, O. Abe, A. Hinuma* and T. Saino*
Short-term variation of triple oxygen isotopes and gross oxygen production in the Sagami Bay,
Central Japan. Limnology and Oceanography, 51(3), 1432-1442, 2006.
Sarma, V.V.S.S.*, T. Saino*, K. Sasaoka, Y. Nojiri, T. Ono, M. Ishii, H.Y. Inoue and K.
MatsumotoBasin-scale pCO2 distribution using satellite sea surface temperature, Chla, and cli­matol­ogicalsalinity in the North Pacific in spring and summer. Global Biogeochemical Cycles, Vol.20,
GB3005, doi:10.1029/2005GB002594, 2006.
Shusse, Y. and K. Tsuboki*
Dimension characteristics and precipitation efficiency of cumulonimbus clouds in the region
far south from the Meiyu front over eastern Asian continent. Monthly Weather Review, Vol.134,
1942-1953, 2006.
Sukigara, C. and T. Saino*
A 7-year increasing trend of 15N in sinking particles at the mouth of the Tokyo Bay. Geo­physical Research Letters, Vol.33, No.9, L09607, 2006.
Takahashi H.G.* and T. Yasunari*
A Climatological Monsoon Break in Rainfall over Indochina in the Summer and its In­fluenceon the Seasonal March of the Asian Monsoon Circulation. Journal of Climate, 19-8, 1545-1556,
2006.
Tao, W.-K., E.A. Smith, R.F. Adler, Z.S. Haddad, A.Y. Hou, T. Iguchi, R. Kakar, T.N.
Krishnamurti, C.D. Kummerow, S. Lang, R. Meneghini, K. Nakamura*, T. Nakazawa, K.
Okamoto, W.S. Olson, S. Satoh, S. Shige, J. Simpson, Y. Takayabu, G.J. Tripoli and S. Yang
Retrieval of latent heating from TRMM measurements. Bulletin of American Meteorologi­cal
Society, 87, 1555-1572, 2006.
Ushiyama, T., R. Shirooka, T. Chuda, H. Kubota, S. Iwasaki, J. Chen, K. Takeuchi and H.
Uyeda*
An isolated cloud band around a typhoon in the western tropical Pacific. Geophysical Research
Letters, 33(12), L12808, doi:10.1029/2006GL02100, 2006.
Wakazuki, Y., K. Tsuboki* and T. Takeda
Periodic evolution of multiscale precipitation systems developed within a Baiu frontal cloudcluster. Journal of the Meteorological Society of Japan, 84(3), 497-518, 2006.
Wang, B., P. Webster, K. Kikuchi, T. Yasunari* and Y. Qi
Boreal summer quasi-monthly oscillation in the global tropics. Climate Dynamics (CD) 27, 7/8,
661-675, 2006.

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39
31.

32.

33.

34.

35.

002.HyARC2006-Pub.indd 39

Yamada, H. and H. Uyeda*
Transition of the Rainfall Characteristics Related to the Moistening of the Land Surface over
the Central Tibetan Plateau during the Summer of 1998. Monthly Weather Review, 134(11),3230-3247, 2006.
Yasunari, T.*, K. Saito and K. Takada
Relative Roles of Large-scale Orograghy Land surface processes on Global Hydro-climate. Part
I. Revisit to Role of Land-Atmosphere Interaction on Asian Monsoon System. Journal of
Hydrometeorology, 7, 626-641, 2006.
Yasunari, T.* and T. Miwa
Convective Cloud Systems Over the Tibetan Plateau and their Impact on Meso-scale
Disturbances in the Meiyu/Baiu Frontal Zone — A Case Study in 1998 —. Journal of the
Meteorological Society of Japan, 84-4, 783-803, 2006.
Zhang, C.Z.*, H. Uyeda*, H. Yamada and B. Geng
Characteristics of Convections of Medium Depth to South of the Meiyu Front Analyzed byUsing Numerical Simulation. SOLA (Scientific Online Letters on the Atmosphere), Vol.2,
160-163, doi:10.2151/sola.2006-041, 2006.
Zhang, C.Z.*, H. Uyeda*, H. Yamada, B. Geng and Y. Ni
Characteristics of Mesoscale Convective Systems over the East Part of Continental China
during the Meiyu from 2001 to 2003. Journal of the Meteorological Society of Japan, 84(4),763-782, 2006.

08.2.1 1:40:55 PM

Hydrospheric Atmospheric Research Center (HyARC)
Nagoya University
Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
Office:Telephone: +81-52-789-3466
Facsimile: +81-52-789-3436
Home Page: http://www.hyarc.nagoya-u.ac.jp/hyarc/

The 2006 Annual Report was published December 2007
by the Hydrospheric Atmospheric Research Center (HyARC)
Nagoya University. Copies of this report are available fromthe office of the Center.

Printed by Nagoya University COOP

Annual Report

Hydrospheric Atmospheric Research Center(HyARC)
Nagoya University

2010