华北地区动力和热力蒸发量特征研究

选用1957~2002年的气象观测资料,对华北地区5个分区动力和热力蒸发量的季节、年际变化规律,动力和热力蒸发量之间的差异,动力和热力蒸发量对总蒸发量的贡献以及近20年全球变暖背景下华北地区动力和热力蒸发量的变化趋势进行了分析.结果表明,华北各个区域动力和热力蒸发量的年、季变化规律有明显差异,动力蒸发量的季节变化呈双峰特征,而热力蒸发量则呈单峰变化.动力蒸发量和热力蒸发量的年和季节序列线性变化趋势有明显差异,在全球变暖的背景下,这种差异明显变大.年平均热力作用对总蒸发量的贡献大于动力作用,不同季节这种规律有所不同,温暖季节热力作用对总蒸发量贡献较大,寒冷季节动力作用大于热力作用(华北4区除外).

Characteristics of dynamic evaporation and thermal evaporation in North China

Based on the observed meteorological data from 1957 to 2002,an analysis was made of seasonal and annual variations of dynamic evaporation and thermal evaporation,their differences,and their contributions to the total amount of evaporation of 5 regions in North China,as well as the trend of their variations for recent 20 years under the condition of global warming.The results show that there are obvious differences between seasonal variations of dynamic evaporation and thermal evaporation in different regions,the former being double-peak distributed,while the latter being single-peak distributed,and that obvious differences also exist between annual variations of dynamic evaporation and thermal evaporation,and the differences become more evident under the condition of global warming.It is also demonstrated that the contribution of average annual thermal evaporation to the total amount of evaporation is greater than that of average annual dynamic evaporation,while the situation is quite different in different seasons: in warm season,thermal evaporation is of greater contribution to the total amount of evaporation of these regions,however,apart from the fourth region,the dynamic evaporation is of greater contribution to the total amount of evaporation in cold season.