GAME-JPの皆様: 東大の沖です。
IAHS 2001(国際水文科学会、マーストリヒト、オランダ、2001年7月)の
アブストラクト申し込み締め切りは4月15日でしたが、集まりが今一つ
悪いので、締め切りが1ヶ月伸びて5月15日になりました。詳しいことは
http://www.wlu.ca/~wwwiahs/
をご覧ください。私がお役を仰せ付かったのは、
S5 Soil-Vegetation-Atmosphere Transfer schemes and large-scale
hydrological models
S5.1 SVAT and precipitation-runoff process modelling at large catchement
(>1000km2), regonal and continental scales
S5.2 Parameter estimation of large-scale hydrological models
S5.3 Data assimilation in large-scale hydrological models
S5.4 Snow-vegetation interactions
というセッションです。このセッションに申し込まれる方は、奮ってDolman氏
>Han Dolman
>Alterra
>Droevendaalse steeg 3,Wageningen, the Netherlands
>Mail address:
>PO Box 125, 6700AC
>Wageningen, the Netherlands
>tel (31)317-474304
>fax(31)317-424812
まで300〜400字のabstractをご送付ください。正式論文投稿は10月1日締め切り
となる予定です。Proceedingsは査読を受け、水文分野では国際的に非常に流通
の良いIAHSのRed Bookとして出版されます。2001年はGAMEの最終年度だは、CEOP
は始るは、Precipitation Conferenceはマサチューセッツであるは、IAMASはあ
るは、と大いそがしかも知れませんが、よろしくご検討ください。
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沖 大幹＠東京大学生産技術研究所 （cc:に無神経）
〒153-8505 東京都目黒区駒場4-6-1、東京大学生産技術研究所B棟 Be607
Phone: (03) 5452-6382, Fax.: (03) 5452-6383
taikan@iis.u-tokyo.ac.jp http://hydro.iis.u-tokyo.ac.jp/
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S5 Soil, Vegetation, Atmosphere Transfer schemes and large scale
hydrological models
Confirmed Leading Commission: ICASVR
Co-operation with: GEWEX*, IAHS/WMO Working Group on GEWEX, ICRS, ICSI
Working Group on Snow-Vegetation Interactions
Confirmed principal convenor: Han Dolman < dolman@sc.dlo.nl >
Possible co-convenors: Alan Hall, Lev Kavvas, T. Koike, John Pomeroy,
Various Soil-Vegetation-Atmosphere Transfer (SVAT) schemes have been
developed for use with General Climate Models (GCMs), Regional Climate
Models (RCMs), Numerical Weather Prediction Models (NWPMs), coupled
atmospheric-hydrological models and large-scale hydrological models.
However, SVAT models face various difficulties that include:
* comparable complexity between system components;
* scaling incongruities between atmospheric, hydrological, cryospheric
and terrestrial components;
* advection, mixing and redistribution of mass and energy at sub-grid
scales;
* validation of SVATs at appropriate space and time scales. The need
for improved characterisation of soil and land surface properties at
regional and global scales is generally recognised. This involves
aggregation over heterogeneous surfaces;
* General lack of understanding of the SVAT processes and associated
models in snow-covered areas, particularly as affected by the evolution of
vegetation communities
Current soil-vegetation-atmosphere transfer (SVAT) schemes include
increasingly complex descriptions of the physical mechanisms governing land
surface processes. These schemes require large numbers of soil and land
surface parameters controlling the vertical fluxes. The underlying rationale
is that improved process representation will result in parameters which are
easier to measure or estimate and in improved model performance and
robustness. However, this is not necessarily so, mainly because SVAT models
require effective values for the various parameters at patch, regional or
larger scales, which are not easily estimated and because redistribution of
water and energy at sub-grid scales can alter surface properties. Surface
energy fluxes can vary significantly in space and time due to the
variability in land surface properties and to local scale advection. Recent
studies have shown that characterising such properties is fraught with
difficulties, as determining representative parameterisations is non-trivial
due to our inability to accurately measure land-surface properties. These
issues are particularly difficult to address for snow-covered areas, where
vegetation communities are strongly coupled with patterns of snow
accumulation and melt. The snow and vegetation interactions influences mass,
chemical and energy exchanges. Furthermore, the vegetation is affected by
the sensitivity of the vegetation to snow thermal insulation and spring time
inputs of meltwater, nutrients and latent heat. Current snow models and
parameterisations presume stationary plant communites as part of their
regional calibrations.
The objective of the symposium is to present progress in SVAT modelling and
large-scale hydrological modelling, with some emphasis on the processes and
model development in snow-covered areas. Suggested subtopics for the
symposium include:
S5.1 SVAT and precipitation-runoff process modelling at large catchment
( >1000 km2) , regional and continental scales (Hall)
The modelling of SWAT, water balance and precipitation-runoff processes at a
range of space and time scales are key issues for the integration of
landsurface process models in atmospheric models and hydrological processes
in large catchments. Distributed hydrological models are required to
accommodate spatial information on the heterogenity of land surface
characteristics and nonlinearity both in the component hydrological
processes as well as their interaction with atmospheric processes. Papers
are sought on physically based, distributed modelling of scaling of
hydrological processes in space and time, starting from the catchment scale
opto the continental scale. Papers on the sub-grid scale of hydrological
parametrization (such as hillslope runoff processes and soil water flow
processes) within catchment and larger-scale distributed
precipitation-runoff and SVAT models are encouraged.
S5.2 Parameter estimation of large-scale hydrological models (Kavvas)
Land surface characteristics are heterogeneous at all scales including at
the scale of the land surface discretization in a distributed catchment
model. Within a numerical grid element topography, vegetation
characteristics (LAI, vegetation height, root depth) and soil
characteristics (retention and hydraulic conductivity functions) will
exhibit spatial variation. Effective parameters representing the integrated
behavior of the processes over the scale of a numerical unit are thus
required. Derivation of effective land surface parameters is inevitably very
complicated due to the non-linear and interacting processes involved. Papers
are invited dealing with theoretical derivation of effective parameters
(deterministic and stochastic averaging) and inverse identification based on
field observations.
S5.3 Data assimilation in large-scale hydrological models (Oki)
Distributed catchment models requires specification of the relevant
parameters at every spatial unit included in the model. Obviously, this
information can rarely be established from traditional point measurements
and monitoring networks. Therefore satellite and radar derived spatially
distributed data on vegetation characteristics, soil moisture and
precipitation will constitute valuable information that may be used as
either input to the model or for updating. Papers are invited dealing with
data assimilation of traditional and remote data in distributed hydrological
models.
S5.4 Snow-vegetation interactions (Pomeroy)
High latitude and altitude vegetation communities are strongly linked to
patterns of snow accumulation and melt at local, basin and continental
scales. Processes driving this linkage involve mass and energy exchange
through the snow and from the snow at the time of seasonal melt. Many snow
models and parameterisations presume stationary distributions of plant
communities as part of their regional calibrations. With global change the
stability of the interaction of vegetation communities and snow phenomena
needs to be examined. Papers are solicited that help to explain current
snow-atmosphere exchange and snow hydrology as affected by vegetation
community, express available data for addressing this issue and suggest
means of anticipating changes in this interaction under environmental
stress.