Water Balance of Paleolake Qinghai and Its Precipitation Estimation at Three High Lake-Level Stages since 40 kaBP

Abstract

孢粉学、地貌学与沉积学的证据揭示了青海湖自 4 0 ka BP以来经历了至少三期高湖面,即 30-40 ka BP,11-13ka BP,7.5-5ka BP.其中第一期与第三期的高湖面是全球性暖湿气候的产物,第二期的高湖面同暖湿气候及高山区冰川消融均有关系.根据 M.N.Bydukko(М.И.Булыко)公式和 J.E.Kutzbach公式计算年蒸发量,依据封闭流域全流域水面平衡模式,模拟了青海湖在第一期与第三期高湖面时的平均降水量分别为 645+/-5mm,595+/-15mm左右;分别比现代湖区降水量高 280 mm,235+/-15mm.从而三期高湖面的高度分别高出现代湖面 10 4 m,10 4 m和 4 5m左右.;Some evidences from geomorphy, pollen and sediment have shown paleolake Qinghai has undergone at least three high-level stages since 40kaBP i.e.30-40kaBP, 11-13kaBP, 7.5-5kaBP.The second high lake-level stage was relevant to ice melting and wet/warm climate, while the other two stages are relevant to the whole global wet/warm climate.Using M.N.Byduko's equation of heat and water balance, and J.E.Kutzbach's equation of energy balance to compute the ground evaporation, the hydrological and energy balance of paleo-lake Qinghai as well as the water balance model of the whole closed basin, is estimated, i.e., the paleoprecipations of paleolake Qinghai are 645+/-5mm/a during 30-40kaBP, 595+/-15 mm/a during 7.5-5kaBP, which are 280mm and 235+/-15mm higher than current precipitation in Qinghai Lake area respectively-As a result, the corresponding high lake-level stages are deduced. During 30-40kaBP, 11-13kaBP and 7.5-5kaBP in Paleolake Qinghai, the paleo-lake level might be 104m, 104m and 45m higher than current Qinghai Lake level respectively.