 |
| | | | | Rainfall Variability | |
| |
|
|
| Cambodia
|
 |
|
|
|
|
|
|
|
|
Cambodia |
|
|
|
|
|
|
|
|
|
Data
In order to apply the methodology used on the global scale with higher
spatial and temporal resolution in the period 1983 to 2002 dekad rainfall
grids at a spatial resolution of approx 0.1 degree are computed.
Concerning Burkina Faso, 133 rainfall stations have been available for
the selected time horizon. In this case interpolation techniques
can be applied directly on rainfall station data. The interpolation has
been performed with inverse distance and regression methods provided within
SEDI (AMS).
For Tanzania, Cambodia and Nepal available stata data was insufficient. So,
the generation of the rainfall grids has been achieved through a "downscaling"
procedure of global NOAA rainfall grids having a monthly resolution and a
spatial resolution of 0.5 degrees. Within this procedure for each of the
three countries a "virtual" grid of rainfall stations is constructed with a
densitiy and distribution of grid points comparable to the station data in
Burkina Faso. After the extraction of the rainfall data for each grid point
from the global NOAA rainfall grids, inverse distance and regression methods
(SEDI) are used again in order to generate the desired spatial resolution.
In coherence with Burkina Faso, most interpolation has been carried-out using
the inverse distance technique. Finally, the monthly rainfall grids are converted
to dekadal grids using a utility by R. Gommes.
The rainfall maps and the maps presenting the rainfall index for agroecological
zones and the first administrative level concerning Burkina Faso and Tanzania
are in Hammer-Aitoff projection and all maps concerning Cambodia and Nepal
are in Goodes Homolsine projection.
Climatological facts about Cambodia
The heart of the country is the alluvial plain drained by the Mekong river.
The Dangrek Mountains form the frontier with Thailand and the Cardamom Mountains
and the Elephant Range are in the southwest. About half the land is tropical
forest. Cambodias climate is like the rest of Southeast Asia governed by the
monsoons. In summer, moisture-laden air, the southwest monsoon, is drawn
landward from the Indian Ocean. Heavy rainfall and high humidy prevails from
mid-May to October. The flow is reversed during the winter. From November to
March the drier and cooler winds from the northeast monsoon bring
variable cloudiness and infrequent precipitation. During the rainy season,
the Mekong river swells and backs into the Tonle Sap Basin. This may increase
the lake almost threefold. The seasonal rise of the Mekong floods the soils
around the lake and leaves rich silt when the waters recede.
Rainfall around the Tonle Sap Basin increases with elevation. It is heaviest
in the mountains along the coast in the southwest. But this area of greatest
rainfall drains mostly to the sea. Only a small quantity goes into the rivers
flowing into the basin.
Rice and rubber are traditionally the principal exports of Cambodia. But most
of the rubber plantations were out of operation with the onset of the civil war
(1970). By the 1990s rubber and rice where again being exported. The fishing
industry has also been revived, but some food shortages continue. By the mid
1990s timber had become the largest source of export income.
|
|
|
