Abstract:

Based on the conventional meteorological data of 43 weather stations in different ecological function areas of Qinghai Province during 1964-2013, the temporal and spatial variation characteristics of pan evaporation were analyzed in the past 50 years, and their change causes of pan evaporation in four ecological function areas were analyzed by using the full correlation analysis. The results showed that the annual and seasonal changes of pan evaporation were significant in different ecological function areas of Qinghai Province. In the recent 50 years, the pan evaporation in Qaidam Basin and three river source area showed a significant decreasing and increasing trends, respectively, while that in Qinghai Lake area and eastern agriculture area hadn’t obvious change trend. The annual evaporation in four ecological function areas decreased firstly and then increased during 1964-2013, but the change time was not completely consistent. The spatial distributions of annual pan evaporation decreased from northwest to southeast, and that in spring, summer, fall was similar to the annual, but that in winter decreased gradually from south to north. The annual pan evaporation mutated in 1998 in Qaidam Basin and in 2002 in eastern agriculture area, while that didn’t mutate in three river source area and Qinghai Lake area during 1964-2013. The influences of climate factors on evaporation were different in four ecological function areas of Qinghai Province.The main climate factors affecting evaporation in Qaidam Basin were wind speed, sunshine hours, average temperature and daily range of temperature, those were average temperature, wind speed and daily range of temperature in Qinghai Lake area, and in eastern agriculture area those were wind speed and relative humidity. However, the effects of average temperature and relative humidity on the increasing of pan evaporation in three river source area were critical.

Key words:  pan evaporation, climate mutation, different ecological function areas, Qinghai Province

摘要：

选用1964～2013年青海省43个气象站常规观测资料，分析4个生态功能区蒸发皿蒸发量的时空变化特征，并采用完全相关法进行蒸发皿蒸发量变化趋势的成因分析。结果表明：近50 a来，青海省4个生态功能区蒸发皿蒸发量的年和季节变化特征明显，柴达木盆地和三江源区年蒸发量整体分别呈显著下降和上升趋势，而环青海湖区和东部农业区变化趋势不明显；4个生态功能区年蒸发量均呈先降后升的阶段性变化特征，但转换时间不尽一致。青海省春、夏、秋季和年蒸发量均从西北向东南逐渐减小，冬季从南向北逐渐减小。柴达木盆地和东部农业区年蒸发量突变时间分别是1998年和2002年；环青海湖区和三江源区突变不明显。影响青海省4个不同生态功能区年蒸发量的主要气象因子不同：柴达木盆地为风速、日照时数、平均气温和气温日较差，环青海湖区为平均气温、风速和气温日较差，东部农业区为风速和相对湿度，平均气温、相对湿度和气温日较差是三江源区蒸发量上升的主要因素。

关键词: 蒸发皿蒸发量, 气候突变, 不同生态功能区, 青海省