Frontier Observational Research System for
|Here, we Like to introduce the activities
of researchers of the FORSGC who work on
global change together with the FRSGC. In
the most recent issue, Dr. Tetsuo Ohhata,
group leader of the Hydrological Cycle Observational
Research Program, explains the intensified
observation of the hydrological cycle in
Siberia during the year 2000.
|| The Year 2000 intensified observation
Hokkaido University,The Institute
Temperature Science, also a scientist
| The characteristics of heat and water exchanges
on typical land in the Siberian
a scale of several kilometers),and
the accumulation and outflow
of water on
the land surface,have become
to research gathered over the
In the year 2000 ,we will intensify
ground observations,and introduce observation
using airplanes,to clarify the three dimensional
structure and seasonal variation of the atmosphere-
land system.In the Taiga zone,along the Lena
River,about 70 %of the land is covered with
Taiga forests.Other areas are bare lands,
grasslands,and watery lands,including areas
such as lakes and rivers.In the forests,
the most predominant kind of tree,among several
other kinds,is larch.Further,the kind of
tree,tree density,tree height,and tree age
all depend on the respective forests in which
they grow.These differences in land areas
correspond to those of responses of water-
energy,and to atmospheric forces, which cause
the seasonal and daily variations.In the
atmosphere- land system, its variety is reflected,and
still a peculiar feature is maintained,responding
to non-linear dynamics independently.
Over time,this atmosphere- land system
exhibits certain features.The snow cover,
existing from winter to spring,and having
high albedo,controls hydrological circulation
rhythm and a certain amount of energy circulation.
In addition,as the temperature increases
and frozen soil thaws,deciduous trees have
leaves,and they start to operate as part
of a water- heat exchange process through
the evaporation of water.
The formation- extinction of the snow
cover and the accretion of the leaves control
water- energy circulation rhythm,but its
extent of the control largely depends on
Therefore,we expect to answer to the
(1 )How does the land area in this district
respond to the atmospheric forcing? What
kind of characteristics and variability does
water- heat exchange have?
(2 )What kind of characteristics does the
water/energy regime have in the atmosphere-
land system during each time period of seasonal
change?How is its time variation?What kind
of influence do the snow cover and forests
have over the state?
(3 )Can we apply the existing various models
of one- dimension water- heat exchange,and
of the atmospheric processes, to Siberia?
In the year 2000 ,we will take the
following four new measures.An outline of
the observation is shown in Figure 1 .
(1 )The ground observations of water-energy
exchange on a patch scale will be increased,totaling
five sites of tower- mast and four spots
of simple observation in a wide area;in the
forests along the left and right coasts of
the Lena river,and on the grass lands.
(2 )We will measure sensible heat and latent
heat (heat transported by water vapor)in
a wide area,and collect water vapor samples
by aircraft observations.
(3 )We will intensify sonde observation at
four sites near Yakutsk.
(4 )We will investigate the applicability
and reproducibility of the one
water-heat exchange model and
model,based on various data.
The observation area is the northern
side of Yakutsk,including Spasskaya Pad and
Tynguru in the Alas zone.The term for intensified
observation is scheduled from April to June
2000 ,and includes time periods of fallen
snow and melting snow, before and after the
forest leaves come out. During that period,we
will make nine flight observations from April
10 through June 20 .
Figure 1 : Conceptual figure
on 2000 intensified