用水热平衡模型估算青海湖古水文要素及水量平衡

ESTIMATES OF PALEO-HYDROLOGICAL PARAMETERS AND WATER BALANCE OF QINGHAI LAKE WITH ENERGY-WATER BALANCE MODEL

根据水热平衡原理，推导了内陆湖泊水位高低（或面积大小）与流域降水及蒸发之间的定量关系，设计了青海湖古水量平衡计算模型。用现在的湖区气象要素及水量收支对模型进行了检验，然后将此模型用于估算全新世稳定暖湿期（7200－6000aB．P．）的青海湖古水文要素及水量平衡。结果显示，在全新世稳定暖湿期，青海湖流域的降水、蒸发及径流比现代高约32％，13％和67％。反映出该地区因气温高、降水增加造成的季风加强使得该地区的水量收支与现代相比有较大的不同。本方法用古湖水位来定量恢复古水文、气候参数，为此可以从古湖泊中提取古气候信息。

Based on the principle of energy and water balance of inland lake with a closed dranage basin, an energytwater balance model was constructed by deriving the funchon of lake level change relating to the change in precipitahon and evaporahon in the lake basin, and used to quanhfy the hydrological parameters and water balance of Qnghai Lake in the 7 200-6 000a B- P. stable warm and wet periods during the Holocene. The basin was divided into severa sechons according to the terrain coverage.The model was applied to each section. The inputs were the lake level and other meteorological data such as cloudiness and temperature, the outputs were evaporation and precipitahon which were summed up into the lake water balance to derive the mnoff With recent observahon records of hydrology and meteorology, the model was validated by the eshmates of energy and water balance during the observahon Period.The results show that the eshmated precipitahon matehes the observahon very well.Hence mis model may be used to eshmate the water and energy balance for the Qinghai paleolake and the paleo-hydrological parameters such as precipitation and runoff The geologic data of the Qinghai paleolake basin duting 7 200-6 000a B. P.were used to run the model. The results of the reconstruction of the water balance of the Qinghai paleolake in the middle Holocene show that precipitation, evaporation and runoff for the lake were 32%, 13% and 67%, respectively, higher than those of today,with an increase in mnoff being two times more than in precipitation. This also implies that the enhanced East Asia monsoon in the Qinghai Lake area produced a warm and wet condihon during the middle Holocene. This research is an attempt to reconstruct quantitatively paleo-hydrological parameters and to interpret the paleoclimate using the paleolake evolutionary evidence.