Masaki TOKITA
Development of the hydro-climatic data set in China land and its preliminary analysis
Minjiao LU
In recent years, abnormal weather condition occurs frequently in China. Damages caused by its influence, are estimated to be about 3 trillion 600 billion yen. To reduce the damages, it is necessary to understand weather situations in China. In this research, precipitation, runoff, the actual amount of evaporation, runoff ratio, the pan evaporation amount is collected to create a hydro-climatic data set, and a simple analysis is carried out.
In Northwest China with spread desert area, the amount of runoff is hardly generated because water is absorbed by the soil even if there is precipitation. Precipitation increases gradually toward the southeast, runoff, the actual amount of evaporation also increase. However the amount of the actual evaporation seems to be limited while runoff and the runoff ratio keep increasing.
In this way, the weather factors that varies from region to region are different because potential evaporation amount which is determined by weather factors such as the amount of solar radiation was considered important. The potential evaporation amount, theoretically it requires many meteorological data, is estimated by multiplying a coefficient to the pan evaporation with a high correlation. In order to determine the coefficients, the widely studied empirical equations based on Budyko framework, are used. Obtained coefficients range 0.5 to 0.6. Generally coefficients to evaporation from to convert considering the conversion from A class pan to lake surface, small pan to A class pan, are 0.6 to 0.7. It can be say that results showed reasonable values since it has been known that pan evaporation amount is higher than the other.
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