Summary of the result obtained byGAME-Siberia and future research issues
Tetsuo Ohata1, Yoshihiro Fukushima2 and Takeshi Ohta3,1
1:Institute of Observational Research for Global Change/JAMSTEC, Yokosuka, Japan
2:Research Institute for Humanity and Nature, Kyoto, Japan
3:Graduate School of Bioagriculture Sciences, Nagoya University, Nagoya, Japan
Email: ohatat@jamstec.go.jp
1. Introduction
In order to advance the study, our study
group set up the following objectives(FromGAMEISP,
1998).
1) Clarify the physical processes of theland-surface / atmosphere interactingsystem.
2) Clarify the characteristics andvariability of regional energy/water cycle.
3) Obtain the climate trend andland-surface change during the past 50
years and evaluate possible feedbackprocesses.
4) Improve and develop models
describing the energy/water exchange
and atmosphere-land surface systems.
5) Collection and archive regional
ground based/satellite data.
6) Establishment of observational
network for long-term study, anddevelopment of hardware.
2. Strategies
The
four
main
strategies
for
implementation were set.
1)Select one large drainage for study,
which was Lena River, eastern mostdrainage among the three large Arctic
flowing rivers. Yenisei and Ob was a
candidate at the beginning, but they
were omitted due to warmer climate
and more anthropogenic influencethan Lena.
2)To establish three local observationsites for intensive study from thecriteria of land surface condition andclimate in the drainage (Tundra areafacing Arctic Ocean, flat taiga withlittle precipitation, mountain taiga
withmuchprecipitation).
The
location of these sites are shown inFig. 1.
3)To hold an intensive study period
for investigating the land surface /atmosphere interaction and spatial
andtemporalvariability
ofwater/energy fluxes in a regional
scale (100km scale), which wasimplemented in year 2000.
4)Involve researchers of various
disciplines
otherthanmeteorology/climatology,hydrology
and glaciology, such as biology, soil
science and others that can contributeto
the understandingof
thewater/energy cycle in this region.
3. Main results
The main results derived fromobservations and analysis are thefollowings. The main papers which arealready published are cited.
(1) Understanding of the annual landhydrological processes were clarified,for first time for a Siberian watershed(5.5 km2). Similarity and difference of
land
surfaceconditionandhydrological process from tundra ofNorth
America
wereshown.
Importance of winter snow process
wasfound.
A
annuallandhydrological model was developed
and from this future variability ofhydrological processes under future
warming were discussed. (Hirashima

et al., 2004)(2) The seasonal variation, predominant
processes of heat/water exchange for
Taiga forest were clarified, anddifference among species and ages
were clarified using three towersystems. Good quality tower data-set
were established. (Ohta et al/, 2001;
Hamada and Ohta, 2003; Toba et al.,2002)(3) Hydrological process studies using
stable isotope were developed. The
sub-surface level of uptake of soil
moisture was clarified and stability ofinter-annual evapotranspiration was
confirmed, and characteristics of lakewater variation was found. (Sugimotoet al., 2002; Sugimoto et al., 2003;
Ichiyanagi et al., 2003)(4) Necessity of scale up of heat/water
fluxes were clarified. The differencein the magnitude of sensible/latent
heat fluxes were measured at
grassland and forest, two dominantsurfaces in Taiga region, and theformer
showedlarger
valuesthroughout the snow-free period.
These difference show up-scaling offluxes for evaluating spatial total.
(Yamazaki et al., 2004).
(5) Hydrologicalcharacteristics
ofheadwater regions of Lena River wereclarified. Seasonal variation ofevapotranspiration values differsfrom Taiga in Yakutsk area. Main
runoff amount of snowmelt hascorrelation not only to winter snow
amount, but also to soil moisture
content of previous autumn, meaninginter-annual effect on runoff. (Suzukiet al., 2002)(6) Hydrologicalmodelsofsnowcover/permafrost area was developed,
and showed good simulation to acertain degree. (Ma et al., 2001)(7) Large scale characteristics of water
cycle, land surface conditions such as
vegetation, snow and other wereclarified.
Characteristics
ofspatial/temporal distribution of NDVI,
snow cover depth from satellitesensing, precipitation recycling andsea-saw like pattern of precipitation
for Lena and Ob River drainage werefound. (Suzuki et al.,;Suzuki etal.,;Suzuki and Matsuda, 2004;
Kurita et al., 2003; Kurita et al.,
2003; Fukutomi et al., 2004)(8) Landsurfacemodeling
weredeveloped in good relation withobservation, and influence of land
surface processes to large scaleatmosphericcirculation
wasdiscussed. (Yamazaki, 2001; Takata
and Kimoto, 2000; Takata, 2001)(9) Aircraft
measurementin
spring-summer season found new
boundarylayercharacteristics.
(Hiyama et al., 2003; Strunin et al.,
2004)
(10)
Observation system in cold
region were improved and made basis
forlong-termmonitoring,andCD-ROM was published for data up
to 2000. (Suzuki and Ohata, 2003)
4. Future issues
Severaldevelopment
which
needs future investigation, and also
expansion of study techniques were found.
Some are the followings.
(1) Physiologicalandstructuralcharacteristics of forest need to beinvestigated more to reproduce theseasonal variation of heat/waterexchange. Need to answer thefollowing questions. What determines
the start of the foliation? Is there any
water stress for trees, and when andwhy does it occur? How does thestructure of the trees affect thewater(snow) exchange in the coldseasons?
(2) Stable isotope seems to be useful toolto investigate water cycle, using inaddition to the information on
amount of water cycle.
(3) There were found some lag processes
for hydrological cycle. Precipitation
andrunoff
throughcertaincharacteristics
ofsoil,andprecipitation and evapo-transpiration
through soil and water uptake
process of trees. Detail measurements
and model simulation should lead tointeresting results.
(4) Difference in permafrost and frozen
ground condition lead to differenthydrological consequences. Extensionof study areas and regions will be a
fruitful way for understanding thehydrological influence of frozen
ground. There is a necessity to findthe amount of ice underground andits potentiality of melting underglobal warming.
(5) Large scale snow cover influence toatmospheric condition and circulation(6) Long-term variation study was one of
the main objectives which was set atthe beginning. Such studies are very
important from the standpoint ofglobal change, but could not
implement at necessary degree. Oneof the reason was that, we could not
develop new long-term data-set forthese studies. Another was that maineffort was directed to the process
studies and in-situ observation. It israther important to develop andextend the data-set we already haveto earlier times, and analyze
according to new point of view.
(7) The measurement and detail study
was mostly made for warm season.
Cold season process such as, process
related to snow cover ground freezing
and climate warming of winterseasons, formation of Siberian highwas done not at needed degree. A partof the reason for such condition is thesmall magnitude of water/heat fluxes,
which decrease the interest of land
surface specialist, and difficulty ofmeasurementrelated
tocoldconditions. In order to understand thecold region processes totally, more
effort is needed.
(8) Regional modeling which is a goodtool in order to understand theprocess at certain spatial/temporalscale that can never be could be done
only by in-situ observation, was notimplemented fully, due to scarcity ofhuman resources. These studies need
to be done more.
5. Future prospectives
Proceeding
projectsfor
GAME-Siberia is being considered andsome are implemented. The main are thefollowings.

(1) In relation to above (1), CREST (Core
Research of Evolution of Project on “Roleand function of vegetation in Water
Cycle” has started in November 2002, asa 5 years project. It will focus on(a) Frontier Research System for Global
Change and Frontier Observational
Research Systems for Global Change in
JAMSTEC: Northern Eurasia studies
were done in cooperation with GAME
Project since 1997. This is still continuing
and producing large scale analysis
studies, modeling studies, continuance ofobservational network in eastern Siberia
area which was primarily initiated anddeveloped by GAME-Siberia. Main bodyof Frontier, JAMSTEC will be reformed
and become an Independent Agency fromApril
2004(JapaneseNational
Universities will also change toIndependent Agency) is expected to be
re-organized and extend its research area.
This research activity is presently mainly
lead by Profs. T. Yasunari and T. Ohata.
(b)CREST (Core Research of Evolution of
Science and Technology): Forest function
studies (mainly structure and physiology)
related to water cycle is being done under
this project with more participation of
ecological scientists, taking data at four
study sites from eastern Siberia,
Kamchatka, Hokkaido and central Japan.
The target of this study is to treat forestand trees as variables (land component
which change its size and function
according to time interacting withenergy/water/material cycle). Prof. T.
Ohta of Nagoya University is leading thisstudy.
(c) CliC: CliC Project component in Japan
will start its activity in 2005 (if funded),and northern Eurasia will be one
important component of the study.
Cryospheric component of northernEurasia will be focused under this project.
This component will be strongly
promoted by Frontier Observational
Research System for Global Change incollaboration with Universities. This islead by T. Ohata with strong cooperationof NIPR.