黄河流域旱涝年夏季蒸发计算及其变化

根据我国北方的热量平衡观测资料,地立了计算感热—潜热比的经验模式,用于计算黄河流域旱涝年(1972、1975、1986、1988年)及一般年(1971、1974、1985、1987年)夏季陆面蒸发,并分析其变化特点以及与旱涝的关系。

CHARACTERISTICS OF THE EVAPORATION FOR THE SUMMER DROUGHT AND FLOOD PERIODS IN THE YELLOW RIVER VALLEY

In this paper, an empisical, equation for, estimating the quotient between the monthly sums of sensible anb latent heat fluxes is proposed on the basis of the heat balance data measured during 1958-1960 period at Beijing and Zhenzhow,And the monthly evaporation sums for the months from May to August are estimated with the equa'tion by using an eight-year routine meteorological data in the yellow River Valley . Finally the relationship between the monthly evaporation and precipitiation deviation (%) is discussed.The main results are found as following.1) The errors of the total evaporation rn summer computed with Fq.5 and Eq.7 to those obtained from < Atlas of water Climatology of China> are about -10% for most of the stations in Tab.2.2) The monthly evaporation amounts for the drought years (1972,1975, 1986) range from 12.6 to 30.1 KJ.cm-2 and those for the flood year(l988) is from H.2 to 25.1 KJ.cm-2.3) The summery evaporation amounts in the drought year are greater than that in flood year in area 1 , but on the contrary, those for the drought year in area 3 are less.4 ) The evaporation amounts in summer increase with increasing precipitation sums for the drought year, but do not show consistent trend for the flood year.this is because the effects of precipitation deviation on evaporation in the eastern .part of the studied area are different from; those in the western part for. the flood summer