ACG09-01

Japan Geoscience Union Meeting 2016

MARine Ecosystem Model Intercomparison Project (MAREMIP)
Scott Doney1, *Takafumi Hirata2
1.Woods Hole Oceanographic Institution, 2.Faculty of Environmental Earth Science, Hokkaido
University
Ocean biogeochemistry is strongly influenced by the specific activity of various types of plankton.
In an effort to improve the representation of marine ecosystems, ocean biogeochemistry models have
evolved to include a growing number of organisms aggregated according to their functionality into
"Plankton Functional Types" (PFTs). Such models open up new and exciting avenues of research to
explore interactions between marine ecosystems and climate change on various time scales. The"MARine Ecosystem Model Intercomparison Project" (MAREMIP) aims to foster the development of models
based on PFTs in order to progress towards the resolution of important scientific questions; what
are the impacts of global environmental changes on marine ecosystems, including climate change,
ocean acidification and changes in nutrient input? Are there possible regime shifts associated with
future environmental changes? What is the role of ecosystem structure and biodiversity forbiogeochemical fluxes, marine resources and climate? In this talk, we show an overview of the
MAREMIP activities and science highlights.
Keywords: Marine Ecosystem, Ecosystem Model, Intercomparison©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-01 -ACG09-02

Japan Geoscience Union Meeting 2016

Emergence of multiple ocean ecosystem drivers in a large ensemble suite with an Earthsystem model*Keith B Rodgers1, Jonathan Lin2, Thomas Frölicher3
1.AOS Program, Princeton University, Princeton, USA, 2.Princeton University, Princeton, USA, 3.ETH,
Zurich, Switzerland
Marine ecosystems are increasingly stressed by human-induced changes. Marine ecosystem drivers that
contribute to stressing ecosystems –including warming, acidification, deoxygenation, andperturbations to biological productivity –can co-occur in space an time, but detecting their trends
is complicated by the presence of noise associated with natural variability in the climate system.
Here we use large initial-condition ensemble simulations with an Earth system model under ahistorical/RCP8.5 (representative concentration pathway 8.5) scenario over 1950-2100 to consider
emergence characteristics for the four individual and combined drivers. Using a
1-standard-deviation (67% confidence) threshold of signal to noise to define emergence with a
30-year trend window, we show that ocean acidification emerges much earlier than other drivers,
namely during the 20th century over most of the global ocean. For biological productivity, theanthropogenic signal does not emerge from the noise over most of the global ocean before the end of
the 21st century. The early emergence pattern for sea surface temperature in low latitudes isreversed from that of subsurface oxygen inventories, where emergence occurs earlier in the Southern
Ocean. For the combined multiple-driver field, 41% of the global ocean exhibits emergence for the
2005-2014 period, and 63% for the 2075-2084 period. The combined multiple-driver field reveals
emergence patterns by the end of this century that are relatively high over much of the Southern
Ocean, North Pacific, and Atlantic, but relatively low over the tropics and the South Pacific. For
the case of two drivers, the tropics including habitats of coral reefs emerges earliest, with thisdriven by the joint effects of acidification and warming. It is precisely in the regions withpronounced emergence characteristics where marine ecosystems may be expected to be pushed outsideof their comfort zone determined by the degree of natural background variability to which they are
adapted. The results underscore the importance of sustained multi-decadal observing systems formonitoring multiple ecosystem drivers.
Keywords: Ocean biogeochemistry, Earth system modeling, Large ensemble©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-02 -ACG09-03

Japan Geoscience Union Meeting 2016

Ocean carbon pumps in CMIP5 earth system models diagnosed by a vector diagram*Akira Oka1
1.Atmosphere and Ocean Research Institute, The University of Tokyo
The ocean stores 60 times more carbon than the atmosphere and therefore the ocean carbon cycle hasa critical role in controlling the atmospheric CO2 concentration. The ocean carbon cycle iscontrolled by several ocean pumps such as soft tissue (organic matter) and hard tissue (calcium
carbonate) pumps. In the CMIP5 earth system models, these carbon pumps are explicitly simulated in
the model and controls the level of the atmospheric CO2 concentration. In this study, four types ofocean carbon pumps (organic matter, calcium carbonate, gas exchange, and freshwater flux pumps) aredefined here and a method for diagnosing effects of individual four carbon pumps on atmospheric CO2
concentration is proposed. In my method, the simulated 3-D field of dissolved carbon concentration(DIC), total alkalinity (ALK), phosphate, and salinity are used for diagnosing the strength of eachcarbon pump. In addition, the contributions of four carbon pump components to atmospheric CO2 areevaluated in one figure (the vector diagram); each carbon pump component is represented by one
vector and its contribution to pCO2 can be measured from the difference in the contour values
between the beginning and the end of the vector. The analysis is applied to the climatology and theCMIP5 earth system model simulations. Although all models reproduce the same level of theatmospheric CO2 concentration as the climatology, it is shown that contributions from four carbon
pumps are not the same among models. This study demonstrates that the vector diagram analysis
introduced here is a useful tool for quantifying the individual effects of the ocean carbon pumps
on atmospheric CO2 concentration and also for evaluating the reproducibility of ocean carbon cycle
models.
Keywords: carbon cycle, ocean carbon pump

©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-03 -ACG09-04

Japan Geoscience Union Meeting 2016

Nonlinear Interactions between Climate and Atmospheric Carbon Dioxide Drivers of
Terrestrial and Marine Carbon Cycle Changes from 1850 to 2300
*Forrest M Hoffman1, James Randerson2, J Keith Moore2, Michael L Goulden2, Weiwei Fu2, Charles D
Koven3, Abigail LS Swann4, Natalie M Mahowald5, Keith Lindsay6, Ernesto Munoz6, Gordon B Bonan6
1.Oak Ridge National Laboratory, 2.University of California Irvine, 3.Lawrence Berkeley National
Laboratory, 4.University of Washington, 5.Cornell University, 6.National Center for AtmosphericResearch
Quantifying feedbacks between the global carbon cycle and Earth's climate system is important forpredicting future atmospheric CO2 levels and informing carbon management and energy policies. We
applied a feedback analysis framework to three sets of Historical (1850-2005), Representative
Concentration Pathway 8.5 (2006-2100), and its extension (2101-2300) simulations from the Community
Earth System Model version 1.0 (CESM1(BGC)) to quantify drivers of terrestrial and ocean responsesof carbon uptake. In the biogeochemically coupled simulation (BGC), the effects of CO2
fertilization and nitrogen deposition influenced marine and terrestrial carbon cycling. In theradiatively coupled simulation (RAD), the effects of rising temperature and circulation changes due
to radiative forcing from CO2, other greenhouse gases, and aerosols were the sole drivers of carbon
cycle changes. In the third, fully coupled simulation (FC), both the biogeochemical and radiative
coupling effects acted simultaneously. We found that climate-carbon sensitivities derived from RAD
simulations produced a net ocean carbon storage climate sensitivity that was weaker and a net landcarbon storage climate sensitivity that was stronger than those diagnosed from the FC and BGC
simulations. For the ocean, this nonlinearity was associated with warming-induced weakening ofocean circulation and mixing that limited exchange of dissolved inorganic carbon between surface
and deeper water masses. For the land, this nonlinearity was associated with strong gains in grossprimary production in the FC simulation, driven by enhancements in the hydrological cycle andincreased nutrient availability. We developed and applied a nonlinearity metric to rank model
responses and driver variables. The climate-carbon cycle feedback gain at 2300 was 42% higher whenestimated from climate-carbon sensitivities derived from the difference between FC and BGC thanwhen derived from RAD. These differences are important to quantify and understand because different
model intercomparison efforts have used different approaches to compute feedbacks, complicatingintercomparison of ESMs over time. Underestimating the climate-carbon cycle feedback gain would
result in allowable emissions estimates that would be too low to meet climate change targets. We
further explored the degree to which these nonlinearities affect climate-carbon cycle feedback gain
estimates in CMIP5 models at year 2100.
Keywords: carbon cycle, feedbacks, Earth system model©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-04 -ACG09-04©2016. Japan Geoscience Union. All Right Reserved.

Japan Geoscience Union Meeting 2016

- ACG09-04 -ACG09-05

Japan Geoscience Union Meeting 2016

Can we bet on negative emissions to achieve the 2°C target even under strong carbon cycle
feedbacks?
*Katsumasa Tanaka1, Yoshiki Yamagata1, Tokuta Yokohata1, Seita Emori1, Tatsuya Hanaoka1
1.National Institute for Environmetal Studies
Abstract
Given the narrowing windows of opportunities to stay below 2°C, negative emission technologies suchas Bioenergy with Carbon dioxide Capture and Storage (BioCCS) play an ever more crucial role inmeeting the 2°C stabilization target (Fuss et al. 2014). Negative emission technologies –if
deployable at a sufficiently large scale during the second half of this century –would make the 2°C
target more feasible in the midst of the slow political progress. However, such technologies are
currently at their infancy and their future penetrations may fall short of the scale required tostabilize the warming (Scott et al. 2013). Furthermore, the overshoot in the mid-century prior to afull realization of negative emissions would give rise to a risk because such a temporal but
excessive warming above 2°C might amplify itself by strengthening climate-carbon cycle feedbacks,
which are known to be positive albeit with large uncertainties (Friedlingstein et al. 2006). Whenone considers other classes of carbon cycle feedbacks including those with permafrost thawing andwildfire, such a risk could be even higher. It has not been extensively assessed yet how carbon
cycle feedbacks might play out during the overshoot in the context of negative emissions, while theliterature on carbon cycle feedbacks has burgeoned in recent years.
This study explores how 2°C stabilization pathways, in particular those which undergo overshoot,can be influenced by carbon cycle feedbacks and asks their climatic and economic consequences. We
compute 2°C stabilization emissions scenarios under a cost-effectiveness principle, in which thetotal abatement costs are minimized such that the global warming is capped at 2°C. We employ areduced-complexity model, the Aggregated Carbon Cycle, Atmospheric Chemistry, and Climate model(ACC2) (Tanaka et al., 2013), which comprises a box model of the global carbon cycle, simple
parameterizations of the atmospheric chemistry, and a land-ocean energy balance model. The total
abatement costs are estimated from the Marginal Abatement Cost functions for CO2, CH4, N2O, and BC,
which are derived from Azar (2013).
Our preliminary results show that, if carbon cycle feedbacks turn out to be stronger than what is
known today, it would incur substantial abatement costs to keep up with the 2°C stabilization goal.
Our results also suggest that it would be less expensive in the long run to plan for a 2°C
stabilization pathway by considering strong carbon cycle feedbacks because it would cost more if we
correct the emission pathway in the mid-century to adjust for unexpectedly large carbon cycle
feedbacks during overshoot. Furthermore, our tentative results point to a key policy message: do

not rely on negative emissions to achieve the 2°C target. It would make more sense to gear climate
mitigation actions toward the stabilization target without betting on negative emissions because
negative emissions might create large overshoot in case of strong feedbacks. Our simple approach
illuminates a need for investigating this issue further by using a range of models including
coupled Earth System Model (ESM)-Integrated Assessment Models (IAMs).
References
Azar C., et al. (2013) Meeting global temperature targets—the role of bioenergy with carbon captureand storage. Environmental Research Letters 8 034004
Friedlingstein, P., et al. (2006) Climate–carbon cycle feedback analysis: results from the C4MIP
model intercomparison. Journal of Climate 19 3337-3353
Fuss S., et al. (2014) Betting on negative emissions. Nature Climate Change 4 850-853©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-05 -ACG09-05

Japan Geoscience Union Meeting 2016

Scott V., et al. (2013) Last chance for carbon capture and storage. Nature Climate Change 3
105-111
Tanaka K., et al. (2013) Emission metrics under the 2°C climate stabilization target. Climatic

Change 117 933-941©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-05 -ACG09-06

Japan Geoscience Union Meeting 2016

Development of Integrated Terrestrial Model: a biogeophysical land surface model withhuman components*Tokuta Yokohata1, Akihiko Ito1, Naota Hanasaki1, Gen Sakurai2, Tsuguki Kinoshita3, Toshichika
Iizumi2, Yoshimitsu Masaki1, Tomoko Nitta4, Yadu Pokhrel5, Seita Emori1
1.National Institute for Environmental Studies, 2.National Institute for Agro-Environmental
Sciences, 3.Ibaraki University, 4.Atmosphere Ocean Research Institute, University of Tokyo,
5.Rutgers University
Future climate changes possibly affect eco-system services, water resources, food production,energy supply, etc. It is important to understand the interaction between the changes in thesecomplicated factors. In the present study, we develop an integrated terrestrial model which
describes the natural biogeophysical environment as well as human activities. In the integrated
model, a global vegetation model VISIT (Ito et al. 2012), water resource model H08 (Hanasaki et al.
2008, Pokhrel et al. 2012), crop growth model PRYSBI2 (Sakurai et al. 2015), and land use model
TELMO (Kinoshita et al., in preparation) are coupled to a land surface model MATSIRO (Takata et al.
2003, Nitta et al. 2014), which is a component of global climate model MIROC (Watanabe et al.
2010). Output variables of each sub-model are passed to other sub-models during the time
integration. The time interval of variable exchange is a few hourly or daily. For example, the crop
yields [ton/ha] calculated by PRYSBI2 is used in TEMO which calculate the land use change (crop or
natural vegetation area) of next year. The projected land-use map is used in all other sub-models.
The water resource model H08 considers the irrigation process (water withdrawal from rivers) as
well as dam operations in large rivers, which affects the state of the soil moisture and the riverflows in the land surface model. We will present the state of the model development, and resultsfrom the historical and future simulation.
Keywords: Earth system model, climate change, human activity©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-06 -ACG09-07

Japan Geoscience Union Meeting 2016

A study on spatial and temporal variability of sediment in rivers using global sedimenttransport model
Kiyotaka Mukaida1, *Kei Yoshimura1
1.Atmosphere and Ocean Research Institute, University of Tokyo
There have been a number of studies about sediment transport processes in particle scale to basin
scales, but only few studies so far in a global scale. Particularly, there is no study thatutilizes a single model to simulate sediment transport in all rivers in the globe. Furthermore,this sort of model should be of importance with regards to the Earth System Model (ESM)
development, since ESMs are now being implemented with biogeochemical processes in the atmosphere,
land, and ocean. To link between those, riverine transport process needs to be taken into account.
That is our motivation to develop the global sediment transport model, CaMa-SED. In CaMa-SED,
yield, erosion, transport, and sedimentation processes of soil particles are implemented. Those
processes are highly dependent with soil particle diameters, so that the representative diametersof clay, silt, and sand are taken into account. Sediment yield is estimated depending on slope andprecipitation rate. The horizontal transport is divided into two; suspended flow and bedload flow.
Deposition and re-suspension processes are also implemented. The preliminary results show a good
agreement in total sediment transport in major rivers and more importantly, reasonablecharacteristic of diameter-depended sediment distribution from upper to lower reaches. Furthermore,
the hysteresis between river discharge and sediment transport in Amazon river was reasonably
simulated. That is quite new feature of the model because the classical sediment regime, i.e.,
relationship between discharge and sediment, could not explain the hysteresis behavior. A set ofsensitivity tests revealed that the total amount of sediment transport is highly influential to thedeposition rate for smaller particles such as silt or clay.
Keywords: global sediment transport model, suspended flow, sediment regime©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-07 -ACG09-07©2016. Japan Geoscience Union. All Right Reserved.

Japan Geoscience Union Meeting 2016

- ACG09-07 -ACG09-08

Japan Geoscience Union Meeting 2016

Current state of terrestrial CO2 exchange estimations: progresses and remaining issues*Masayuki Kondo1, Kazuhito Ichii1, Prabir Patra1, Tazu Saeki1
1.Department of Environmental Geochemical Cycle Research, Japan Agency for Marine-Earth Science andTechnology
Terrestrial ecosystems play a critical role in formation of a feedback loop of carbon dioxide (CO2
) in atmosphere with atmospheric reservoir and climate, and thus directing a course of the future
projection of climate change. The research community has spent significant efforts to understandbehaviors of terrestrial ecosystems under a steady rise in atmospheric CO2 concentration andtemperature during the recent decades and deepen knowledge about the regional and global patternsof terrestrial CO2 sinks and sources. estimate the terrestrial CO2 exchange, while seeking
consistency between simulated and observed CO2 concentrations. The bottom-up approach estimates theterrestrial CO2 exchange using ecosystem models, which simulate the ecosystem-scale carbon cycle byconsidering the internal biogeochemical mechanisms of carbon flows for each prescribed vegetation
type and soil.
However, the current estimates of terrestrial CO2 exchange by the bottom-up and top-down approaches
remain inconsistent. As illustrated in the recent IPCC Assessment Report (AR5), the top-down
approach tends to indicate stronger CO2 sinks in temperate and boreal regions than the bottom-up
approach does. Furthermore, the two approaches exhibited contrasting CO2 sink–source patterns in
the tropics; the bottom-up approach indicated CO2 sinks and the top-down approach CO2 sources. As
illustrated by these inconsistencies, a consensus on the geographic distribution of the terrestrial
CO2 exchange has yet to be established among the research community.
In this study, we elaborate the current status and issues of terrestrial CO2 flux estimations by
the top-down and bottom-up approaches. Specifically, we compare the bottom-up estimate from dynamic
global vegetation models that are forced by interannual variations of CO2 concentration, climate
and land use changes, with the top-down estimate from atmospheric CO2 inversions. We show an
improved level of agreement between the two estimates in relation to seasonal variability and,regional and global budgets, since the IPCC AR5. We also discuss the remaining issues causinginconsistency between the two estimates.
Acknowledgments
This research was supported by Environment Research and Technology Development Funds (2-1401) from
the Ministry of the Environment of Japan and Asia-Pacific Network for Global Change Research (APN:
grant#ARCP2011-11NMY-Patra/Canadell).
Keywords: Terrestrial CO2 exchange, Atmospheric CO2 inversion, Ecosystem model simulation©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-08 -ACG09-09

Japan Geoscience Union Meeting 2016

THE CARBON BALANCE OF THE TERRESTRIAL BIOSPHERE IN THE TWENTIETH CENTURY*Sitch Alexander Stephen1
1.University of Exeter
Sitch, S. (1) and the TRENDY DGVM consortium, (1) University of Exeter, UK.
Each year a consortium of Dynamic Global Vegetation Modelling groups perform a factorial set ofglobal simulations over the historical period, 1901 –present, to investigate the temporal andspatial trends in the land sink, and the contribution of land-use to emissions. This activity
contributes the annual global carbon budget updates of the Global Carbon Project. Typical around 10
models are forced with reconstructed observed climate, global atmospheric CO2, gridded fields ofhistorical land-use and land cover changes (LULCC), and nitrogen deposition for a subset of models
which include a fully interactive nitrogen cycle. The TRENDY project will be presented, including
process developments through to the latest Trendy-v4 (1901-2014). Results are used to ascertain theindividual contribution of CO2, Climate, Land-Use and N deposition on the regional and global landcarbon sink. Increasingly offline land surface simulations and coupled ESM simulations use the sameland-surface components and results from each can inform the other. Both TRENDY and C4MIP haveincreasing interest in evaluation activities. Furthermore, observational datasets including thosefrom remote sensing are used to evaluate model performance and help constrain the global landcarbon sink over the past two decades.
Keywords: land-atmosphere interactions, DGVMs, climate-carbon cycle models©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-09 -ACG09-10

Japan Geoscience Union Meeting 2016

Climate-carbon cycle changes during 1000 years in doubled CO2 concentration simulated by
MIROC-ESM*Tomohiro Hajima1, Kaoru Tachiiri1, Michio Kawamiya1
1.Japan Agency for Marine-Earth Science and Technology
Transient climate response to cumulative carbon emission, so called TCRE, is defined as the ratioof global warming to cumulative anthropogenic CO2 emission evaluated when CO2 concentration reaches
the doubled CO2 level from pre-industrial state. This metric is useful because it gives us roughly
estimates on future global warming induced by CO2 emission on the basis of current and future
emission amounts. Since TCRE just characterizes the transient response of climate-carbon cycle, wecannot know what will happen after CO2 concentration is stabilized (or reduced) after mitigation
policies adopted. To estimate the warming degree in such condition and to understand climate-carbon
dynamics in the concentration-stabilized phase, we conducted simulations where CO2 concentration isabruptly doubled from pre-industrial state and fixed over 1000 years, by using an Earth systemmodel (MIROC-ESM). We confirmed from the simulations that after 1000 years have passed, global
warming and land carbon uptake almost ceased but weak carbon uptake by the ocean continues.
Keywords: carbon cycle, climate change, Earth system model, TCRE

©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-10 -ACG09-11

Japan Geoscience Union Meeting 2016

C4MIP simulations, plans and evaluation requirements*Chris Jones1
1.Met Office Hadley Centre
Climate-carbon cycle feedbacks are potentially large and play a leading order contribution in
determining the atmospheric composition in response to human emissions of CO2 and in the setting ofemissions targets to stabilise climate or avoid dangerous climate change. For over a decade The
Coupled Climate-Carbon Cycle Model Intercomparison Project (C4MIP) has coordinated coupledclimate-carbon cycle simulations and in the coming few years C4MIP will be an endorsed activity of
CMIP6. It is hoped that this will encourage widespread adoption of the C4MIP set of simulations andenable increased understanding and predictability of future changes in both terrestrial and marine
carbon cycle.
C4MIP has 3 key strands of scientific motivation and the requested simulations are designed tosatisfy their needs: (1) pre-industrial and historical simulations (formally part of the common setof CMIP6 experiments) to enable model evaluation; (2) idealised coupled and partially-coupledsimulations with 1% per year increases in CO2 to enable diagnosis of feedback strength and its
components; (3) future scenario simulations to project how the Earth System will respond over the
21st century and beyond to anthropogenic activity.
In this talk I will outline some previous C4MIP results and present some key priorities forevaluation. It is clear that in biogeochemical modelling and the drive for increased complexity in
ESMs, process-based model evaluation has not kept pace. As a result there is very large
quantitative spread between CMIP5 carbon cycle results which hinder their usefulness. It is also
the case that we have not been able to show demonstrable progress - as a coherent community - inthe quality and process-realism of our modelling. There are no agreed quality criteria or metrics
which measure whether our ESMs are fit for purpose or if they have improved since the lastgeneration. It is essential that we focus our efforts in the coming years on addressing thisdeficiency. It is not enough that under CMIP6 there are more models within C4MIP analyses or moreadvanced processes. We must be able to demonstrate that we have made real progress since CMIP5 in
our modelling skills, analysis techniques and our ability to constrain future projections.
There are multiple ways of evaluating carbon cycle models. Activities such as TRENDY and OCMIP(part of OMIP) will perform evaluation activities of offline land and ocean components
respectively. It is the role of C4MIP to evaluate the coupled climate-carbon cycle system. Our
primary simulations for this activity will be the coupled historical simulations from 1850 up to
2014. There will be two variants. Within the CMIP “DECK” (the central core of CMIP6) all models
will perform a “concentration driven” historical run. This means the atmospheric concentration of
CO2 is prescribed to follow the historical record. The second variant, which is required for allmodels contributing to C4MIP is a parallel “emissions driven” historical simulation in which CO2emissions are prescribed to the model and the models simulate the time evolution of CO2
concentration.
In order to fully exploit these simulations we need to be prepared with some top-level evaluation
criteria (e.g. as presented by Anav et al 2013); some rigorous process-based criteria and metrics(such as sensitivity of stores and fluxes to environmental drivers); carefully assembled andprocessed observational datasets; carefully defined model diagnostic outputs. Here I will briefly
outline these requirements in the hope of stimulating discussion to move our plans forward ahead of©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-11 -ACG09-11

Japan Geoscience Union Meeting 2016

model simulations being started by the end of 2016.
Keywords: Carbon cycle, CMIP, evaluation©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-11 -ACG09-P01

Japan Geoscience Union Meeting 2016

Millennium-scale changes in ocean carbon cycle under global warming*Akitomo Yamamoto1, Ayako Abe-Ouchi1, Yasuhiro Yamanaka2
1.Atmosphere and Ocean Research Institute, The University of Tokyo , 2.Graduate School ofEnvironmental Science, Hokkaido University
The oceanic uptake of anthropogenic CO2 from the atmosphere is expected to persist for a thousand
years or more. Understanding the oceanic carbon uptake is essential for predicting the air-borne
fraction of CO2 emissions and thus degree of climate change. Warming of ocean surface waters andchanges in the ocean circulation and biological pump would reduce the oceanic uptake of CO2, which
is known as climate-carbon cycle feedback.
In this study, we simulate multimillennium changes in ocean carbon cycle under quadrupling of
atmospheric CO2, using GCM (MIROC) and an offline biogeochemical model. We also carry out a numberof sensitivity runs in order to isolate the individual feedback mechanisms.
The oceanic uptake is 2050 Pg C, and the reduction of uptake due to global warming is about 30% at
the end of simulation. These values are comparable to the previous studies (Plattner et al, 2001;
Schmittner et al, 2008). The increase in SST and weaker soft-tissue pump are the dominantmechanisms of climate-carbon cycle feedback. Important biological mechanisms are reduction in new
production due to reduced nutrient supply and increase in remineralization rate due to seawater
warming.
I will also discuss the effect of ocean circulation change on the oceanic uptake.
Keywords: ocean carbon cycle, multi-millennium simulation, climate-carbon cycle feedback©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-P01 -ACG09-P02

Japan Geoscience Union Meeting 2016

Global-scale swamp forest modelling using satellite-based elevation and forest datasets*Dai Yamazaki1
1.JAMSTEC Japan Agency for Marine-Earth Science and Technology

Swamp forest (seasonally flooded forest) has different characteristics to usual non-flooded forest
in terms of carbon pool and nutrient flux. Swamp forest exists in wide climate regions from boreal
to tropical regions, but its global distribution is not well studied because satellite observationof inundated forest floor is disturbed by vegetation canopy. Here, we propose a method to estimate
the global distribution of swamp forest by global river model simulations using satellite elevationand forest datasets. Digital Elevation Models (DEMs) based on satellite radar or stereoscopy haveelevation biases due to forest canopy that impede the simulation of swamp forest hydrodynamics. We
removed the elevation biases by combining ICESat forest height data and Landsat forest density
data. The simulation with the bias-corrected DEM shows good agreement to L-band radar observationof swamp forest inundation in the Amazon basin, which suggests the potential of the proposed method
for estimating swamp forest distribution.
Keywords: Swamp Forest, Global Motel, Flooding©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-P02 -ACG09-P03

Japan Geoscience Union Meeting 2016

Earth system and climate modeling activities toward CMIP6 in Japan: a review*Michio Kawamiya1
1.Japan Agency for Marine-Earth Science and Technology
There are three groups in Japan planning to contribute to Coupled Model Intercomparison Project(CMIP6): Meteorological Research Institute (MRI) of Japan Meteorological Agency (JMA); Team MIROC,
which is a joint effort among JAMSTEC, the University of Tokyo, and NIES; and NICAM development
team consisting of UT, RIKEN and JAMSTEC. The first two groups are joining most of the endorsed
MIPs with their different model versions combined, while the NICAM team joins CMIP6 in a more
selective manner due to the immense computer resource requirement. The third generation of the
Earth Simulator, whose theoretical computational speed is 1.3PFlops, will be used for most of theCMIP6 experiments, while the K computer may be utilized for some NICAM experiments. Many activities
in Japan for CMIP6 are supported by SOUSEI project funded by MEXT, which is coming to an end in
March, 2017. A forum has been set up to involving both scientists and funding agency to discussoverall direction of climate science beyond SOUSEI project.
Keywords: Earth system model, Climate projection, CMIP6©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-P03 -ACG09-P04

Japan Geoscience Union Meeting 2016

Effect of bias in Leaf Area Index to climate in MIROC-ESM*Kaoru Tachiiri1, Tomohiro Hajima1
1.Japan Agency for Marine-Earth Science and Technology
Leaf Area Index (LAI) is not only an important factor to determine the amount of photosynthesis,but also a key variable to represent ground surface condition which gives significant impact toatmosphere through biophysical processes such as albedo and transpiration. In this study, we firstcompared the present-day LAI in Earth System Models (ESMs) with remote sensing data and confirmed
the significant overestimation by ESMs, which is pointed out by some existing studies. In order toinvestigate the effect of the bias, we next compared two pre-industrial control experiments: anordinary control experiment in which LAI is prognosed by the terrestrial ecosystem component of theESM, and an experiment in which LAI is replaced with dataset made from remote sensing data (thepre-industrial state was estimated by retuning the cultivated areas to natural vegetation). The
result shows a significant temperature difference between the two cases, and by analysis of therelated variables we concluded that the difference is caused by albedo change due to the change insnow depth/coverage in May-June and in the sea ice coverage in winter.
Keywords: Leaf Area Index, bias, MIROC-ESM, climate©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-P04 -ACG09-P05

Japan Geoscience Union Meeting 2016

Socio-economic implications of stabilization scenarios from MIROC-ESM*Diego Silva1, Kaoru Tachiiri1
1.Project Team for Risk Information on Climate Change, Japan Agency for Marine-Earth Science andTechnology (JAMSTEC)
Setting a target for stabilization of climate in the long-term requires significant reductions ingreenhouse gas (GHG) emissions at global scale. This involves important transformations in thesociety, basically affecting the future patterns of energy consumption and production, as well as
the patterns of land use. Moreover, the cost for achieving such climate target may be considerable,thus, requiring an optimal allocation of efforts that minimizes the economic impact. This study
presents the socio-economic implications of emission scenarios aiming at long-term climate
stabilization, estimated with an integrated assessment model (IAM). Emission scenarios are obtained
from the earth system model (ESM) Model for Interdisciplinary Research on Climate (MIROC-ESM). The
outcomes on supply and demand of energy, land use, and mitigation costs are presented.
The emissions scenarios considered are consistent with the representative concentration pathway(RCP), and aim at a global radiative forcing by 2100 of around 4.5 W/m2 (RCP4.5) and 2.6 W/m2
(RCP2.6). The Global Change Assessment Model (GCAM) is applied to study the developments in energy,
land use and emissions throughout the 21st century. GCAM is an IAM based on a partial equilibrium
approach, which resolves the balance in supply and demand across the energy, land use andagricultural sectors.
Compared to the standard RCPs, the emission scenarios from MIROC-ESM presented lower levels ofallowable anthropogenic CO2 emissions for the same climate target. This is an outcome of thestronger feedback between the carbon-cycle and the climate, and the higher value for climate
sensitivity assumed in MIROC-ESM in contrast to the climate model used in the development of RCPs.
As a consequence, the changes in the energy and land systems are more drastic, while the cost of
mitigations is higher. These differences are greater in the second half of the century.
Keywords: MIROC-ESM, stabilization scenario, integrated assessment model©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Mineral aerosol as a source of iron for the marine ecosystems in the Southern Ocean*Akinori Ito1, Jasper F. Kok2
1.Japan Agency for Marine-Earth Science and Technology, 2.University of California, Los Angeles
Atmospheric deposition of dust source materials is a significant source of exogenous iron (Fe) inmarine ecosystems. Especially, the Southern Ocean is the most biogeochemically important ocean
because of its large spatial extent and its considerable influence on the global carbon cycle.
However, there is large uncertainty in our estimate of the dust emissions in the Southern
Hemisphere. Here, we implement a newly developed dust emission scheme into a global atmosphericchemistry transport model to produce better agreement with measurements of Fe loading over theoceans.
Keywords: Aerosols , Global Biogeochemical Cycles, Atmospheric chemistry transport model©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

On constraining the strength of the terrestrial CO2 fertilization effect in an Earthsystem model*Vivek Arora1, John Scinocca11.Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada
Earth system models (ESMs) explicitly simulate the interactions between the physical climate systemcomponents and biogeochemical cycles. Physical and biogeochemical aspects of ESMs are routinely
compared against their observation-based counterparts to assess model performance and to evaluate
how this performance is affected by ongoing model development. Here, we assess the performance ofversion 4.2 of the Canadian Earth system model against four, land carbon cycle focused,
observation-based determinants of the global carbon cycle and the historical global carbon budget
over the 1850–2005 period. Our objective is to constrain the strength of the terrestrial CO2
fertilization effect which is known to be the most uncertain of all carbon cycle feedbacks. The
observation-based determinants include (1) globally-averaged atmospheric CO2 concentration, (2)cumulative atmosphere–land CO2 flux, (3) atmosphere–land CO2 flux for the decades of 1960s, 1970s,
1980s, 1990s and 2000s and (4) the amplitude of the globally-averaged annual CO2 cycle and its
increase over the 1980 to 2005 period. The optimal simulation that satisfies constraints imposed by
the first three determinants yields a net primary productivity (NPP) increase from ~ 58 Pg C yr−1
in 1850 to about ~ 74 Pg C yr−1 in 2005; an increase of ~ 27 % over the 1850–2005 period. The
simulated loss in the global soil carbon amount due to anthropogenic land use change over thehistorical period is also broadly consistent with empirical estimates. Yet, it remains possiblethat these determinants of the global carbon cycle are insufficient to adequately constrain thehistorical carbon budget, and consequently the strength of terrestrial CO2 fertilization effect as
it is represented in the model, given the large uncertainty associated with LUC emissions over thehistorical period.
Keywords: Earth system models, CO2 fertilization effect, Land carbon uptake©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Multi-model analysis of ocean acidification in the subsurface layers of the North Pacific*Michio Watanabe1, Michio Kawamiya1
1.Japan Agency for Marine-Earth Science And Technology
Ocean acidification is one of the major threats for marine calcifying organisms such as precious
corals. They live in the mesophotic waters at a depth of 80–300 m near Japan and are known as
habitat-forming species with an important structural role in mesophotic habitats of continental
slopes, sustaining biodiversity hotspots. Using the outputs of projections under the highest
emission scenario of the Representative Concentration Pathways performed by Earth System Models(ESMs), we evaluate the ocean acidification rates in the middle layers of the North Pacific, where
the strongest sink of atmospheric CO2 is found in the mid-latitudes. The mixed layer depth in the
Kuroshio Extension region reaches ~200 m during winter due to the strong wind forcing and cooling.
Consequently, the low potential vorticity (PV) water mass called the Subtropical Mode Water isformed. This mode water shows large dissolved inorganic carbon (DIC) concentration increase, and isadvected southwestward, so that, in the Izu-Ogasawara region, DIC concentration increases and ocean
acidification occurs faster than in adjacent regions. The ESMs simulate that pH in the middle
layers of the Izu-Ogasawara region decreases by 0.3~0.4 from 2006 through 2100. We find that the
ESMs with a deeper mixed layer during winter in the Kuroshio Extension region show the large
increase in DIC concentration within the Izu-Ogasawara region. For a reliable projection of theocean acidification in the middle layers of the Izu-Ogasawara region, an ESM should well reproduce
the mixed layer deepening during winter in the Kuroshio Extension region.
Keywords: ocean acidification, CMIP5, Earth System Model©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-P08 -ACG09-P09

Japan Geoscience Union Meeting 2016

Measurements of Gaseous Nitrous Acid (HONO) Emission from Activated Sludge andDenitrifying Bacteria*Chika Minejima1, Tomoyuki Miyashita1
1.International Christian University
Introduction
Gaseous nitrous acid (HONO) is known as a precursor of OH radicals, a strong oxidant in theatmosphere. Up to 34 % of OH radical is produced from HONO in a city and a rural area1). Therefore
HONO is an important species to know OH radical behaviors.
The high HONO concentration have been observed during daytime in spite of the HONO photolysis.
There are several known HONO sources: gas phase reactions, heterogeneous reactions and combustion
process. Also, HONO emission from soil by the equilibrium between gaseous nitrous acid and aqueous
nitrous acid in the soil and the direct emission by nitrifying bacteria have been observed2)3). In
the soil, there are not only nitrifying bacteria but denitrifying bacteria. However the emission bydenitrifying bacteria is not studied.
The research purpose is to determine whether or not denitrifying bacteria in the activated sludge
emits HONO directly.
Experimental
HONO emissions from activated sludge in aerobic condition and anaerobic condition were measured.
Also HONO emission from the sterlized supernatant solution was measured. HONO emissions from
biological process and chemical process were compared. Activated sludge in Duran bottle was purged
with air or N2 for 1 day to 4 days and HONO was captured with a filter pack. The sludge was aerobic
with air purge and anaerobic with N2 purge. Duran bottle and filter packs were covered with tin
foil to avoid HONO photodissociation. Dissolved Oxygen was measured to keep the condition ofactivated sludge and pH was stabilized at 7.8-8.1 by adding 0.1 M HCl solution or 50 g/L NaHCO3
solution not to decrease the bacteria’s activity. The flow speed was controlled at 2 L/min withmass flow controllers.
Also, activated sludge and its sterilized supernatant solution were purged with room air and N2 at
22 ℃. Also the activated sludge was purged with N2 at 27, 32 ℃. The activated sludge in a Duranbottle was put in the water which is controlled with a heat controller to stabilize the temperatureof activated sludge. In these experiments, three filter packs were placed for each experiment. Air
or N2 was purged in 4.5 L/min because three filter packs were prepared and the purged gas wascontrolled to flow through each filter pack in 1.5 L/min. The NO2- concentrations of the sludge andsupernatant were measured before these experiments with the pack test. The purging time was 8 hours
in order to keep controlling pH.
Results and Discussion
In this experiment, HONO emissions from the sludge were observed at anaerobic condition. The
contribution of biological process was more than 90%. However, calculated activation energy fromtemperature dependent experiment was much bigger than that of the denitrifying bacteria. Thus,
there is a possibiliy that denitrifying bacteria reduce NO3- to NO2- and the increase in NO2concentration increased the HONO emission from the chemical process. Also, NO2- concentration in
the sludge should be measured more accurately because it has influence on HONO emission.
Reference
1) Wong et al., Atmos. Chem. Phys., 11, 3595-3609 (2011).
2) Su, et al., Science, 333, 1616-1618 (2011).
3) Oswald, et al. Science 341, 1233-1235 (2013).

©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Keywords: nitrous acid, atmosphere, soil

©2016. Japan Geoscience Union. All Right Reserved.

- ACG09-P09 -ACG09-P10

Japan Geoscience Union Meeting 2016

IMPACT OF BIOGEOPHYSICAL AND BIOGEOCHEMICAL PROCESSES AND THEIR INTERACTIONS ON PERMAFROSTSOIL CARBON STOCKS*Jain K Atul1, Shijie Shu1, Rahul Barman1, Bassil El-Masri1
1.Department of Atmospheric Science, University of Illinois
One of the major challenges in more detailed Earth system models (ESMs) is the treatment of thebiophysical and biogeochemical processes and feedbacks and their impact on soil organic carbon(SOC), in the Northern high latitudes (NHL) permafrost region. . This is because a larger suite ofactive terrestrial processes coupled with scarcity of observational data introduce many challenges
for modelling these processes. Nonetheless, several studies in the recent past have demonstrated
improved permafrost modelling capabilities by incorporating soil/snow processes that critically
influence the ground energetics in these environments, such as: deep soil layers and organic soils,
and the effects of wind compaction and depth hoar formations, and structural properties ofvegetation (phenology, assimilated vegetation C allocation to leaves, stems, and roots and root
dynamics) However, no study has yet evaluated the combined effects of the improvements of thesebiogeophysical and biogeochemical processes for the entire NHL.
We use a land surface model, the Integrated Science Assessment Model (ISAM), to investigate theeffects of feedbacks between the biogeochemical (C and N) and biogeophysical (water, and energy)
processes on the model estimated soil organic carbon (SOC) for the NHL permafrost region. We not
only focus on recent model improvements in the biogeophysical processes that are deemed important
for the high latitude soils/snow and ppermafroest SOC; such as deep soil column, modulation of soil
thermal and hydrological properties, wind compaction of snow, and depth hoar formation; but also
biogeochemical processes that are important for soil biogeochemistry; such as dynamic phenology androot distribution, litter carbon decomposition rates and nitrogen amount remaining. We selectmultiple sites to evaluate the modeled processes. We then carried out several model simulations tostudy the effects of feedbacks between biogeochemical and biogeophysical processes on SOC in NHL.
After accounting for dynamic biogeochemical processes, ISAM is able to capture permafrost extend
and and the carbon stored in NHLs, as well as the seasonal variability in leaf area index (LAI),
and root distribution in the soil layers and the root response of soil water uptake andtranspiration. The evaluation of the model results suggest that without accounting these processes,
modelled growing season length (GSL) for NHL was almost two times higher as compared tomeasurements. To quantify the implication of these processes on the carbon and water fluxes, we
compared the results of two different versions of ISAM, dynamic version which accounts for dynamic
processes (ISAMDYN) and static version which do not account for dynamic processes (ISAMBC), withmeasurements from12 eddy covariance flux sites. The results show that ISAMDYN, unlike ISAMBC, isbetter able to capture the seasonal variability in GPP and energy fluxes. Our modelling analysis
shows that by including the biophysical processes in addition to biogeochemical processes, themodelled NHL permafrost carbon increased by 30% from 328 to 447 GtC in the top one meter of soil
which is in better agreement with observational estimates of 495 GtC (Northern Circumpolar Soil
Carbon Database). Even though the inclusion of these processes generally reduced vegetation
productivity and litter production due to a decrease in soil temperature and liquid water content,
increased soil carbon stocks highlight the dominance of soil water/temperature stress on
decomposition processes. While continued improvements are required in the treatment ofbiogeochemistry, here we demonstrate the importance of soil/snow biogeophysical and biogeochemical©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

processes in modelling permafrost carbon stocks, as important drivers of soil biogeochemical
processes.
Keywords: Permafrost Soil Carbon, Land Surface Model, Biogeophysics, Biogeochemistry©2016. Japan Geoscience Union. All Right Reserved.

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