The Lake Biwa Project

1
The Lake Biwa Project
The field observation has been carried out under
the Japanese hydro-meteorological project called
"Lake Biwa Project". A core activity of this
project has been collaborative field observation
synchronized with the spaceborne and airborne
remote sensing. This project aims to understand
the hydrological cycle within the Lake Biwa Basin
together with establishing ways of scaling up and
down the hydrological model within the scale of
100km x 100km. Targets of this project are
(1)validation of satellite remote sensing
(2)development of algorithms/models describing
hydrological processes (3)understanding of
land-atmosphere interactions (4)evaluation of
space/time scale effects in the hydrological
cycle (5)establishment of a land-atmosphere
coupled model for the Lake Biwa Basin Currently,
seasonal variation of energy and water cycle is
gradually being added as one of the targets by
combining the numerical model with operational
information from satellite observation and
established regular in situ observation systems.
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Location of Target Area
20 km
Forest
Lake Biwa
20 km
Paddy Field
Kyoto
Nagoya
Lake
Osaka
Urban Area
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Regular flux measurement system
Now four flux measurement systems have been
installed and operated regularly at different
landuse condition (paddy field, forest, lake,
urban area) in the Lake Biwa Project. Fluxes of
radiation budget and heat budget component and
related meteorological and hydrological variables
are observed continuously.
4
Time series of accumulated water budget
components for Lake Biwa
blue outflow from the Lake (obs) pink surface
runoff from the basin-mesh (sim) black baseflow
from the basin-mesh (sim) red precipitation
over the lake (obs) green evaporation from the
lake (sim) sky blue irrigation water demand
(sim) yellow forced water drainage
(sim) purple lake water storage change
(obs) orange lake water storage change (sim)
Comparison of observation and numerical
simulation by Land Surface Scheme (upper paddy,
lower lake)(left net radiation, rightlatent
heat)
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Intensified field observation of turbulent
fluxes CAPS (Catch a Plume by SATs)
CAPS was carried out in Nov. 2002 to measure the
distribution of surface heat fluxes. 17 SATs were
installed within 1200 x 500m field. Among them,
5 sites were called super site where all energy
budget components were measured. Furthermore, 2
Doppler Sodars, GPS sonde, 4 Scintillometers,
were used to measure the structure of boundary
layer. Surface temperature distribution was
measured by thermometer from airplane.