青藏高原东北部60多年来的气候暖湿化:来自德令哈水文气候的记录

Warming and Humidification of Climate on the Northeastern Qinghai-Xizang Plateau Over the Past 60 Years:Evidence from Hydroclimatic Records of Delingha

柴达木盆地水文气候的变化影响该区生态文明建设及经济社会发展。研究采用线性回归和Mann-Kendall突变检验分析方法对德令哈60多年来的气象和水文数据进行分析。结果显示,德令哈的气温和降水均呈显著的上升趋势,1956—2022年升温速率为0.45℃/10 a,1956—2018年降水增加速率为26.6 mm/10 a。冬季气温升高最快,可达0.75℃/10 a;夏季降水增加最多,为17.1 mm/10 a。德令哈水文站的平均流量也呈显著增加趋势,1960—2020年增加速率为1.03 m^(3)/s/10 a;夏季增加速率最快,为2.89 m^(3)/s/10 a。平均流量主要受控于降水量,气温对其影响次之。Mann-Kendall检验显示平均流量在2009年发生突变。尽管1973—1980年的蒸发量处于高值,但1956—2003年的蒸发量变化总体呈下降趋势,平均风速很可能是影响蒸发量的主要因素。湿润指数(降水量/蒸发量)呈升高趋势,表明德令哈气候近60年来朝湿润化方向发展。托素湖、尕海、青海湖湖面上涨及柴达木盆地植被覆盖度增加进一步印证了青藏高原东北部气候的暖湿化特征。

The variation of hydroclimate in the Qaidam Basin has a significant impact on the construction of ecological civilization and development of economic society in this region.In this study,meteorological and hydrological records in Delingha over the past 60 years were analyzed and the results showed that both temperature and precipitation presented a significant upward trend.The warming rate from 1956 to 2022 was 0.45℃/10 a,and the increase rate of precipitation from 1956 to 2018 was 26.6 mm/10 a.Over the past 60 years,winter temperatures had risen the fastest,reaching 0.75℃/10 a;summer precipitation increased the most,up to 17.1 mm/10 a.The average discharge of Delingha hydrological station also showed an obvious increasing trend,with an increase rate of 1.03 m^(3)/s/10 a from 1960 to 2020;the fastest increase rate of 2.89 m^(3)/s/10 a occurred in summer.The average discharge is mainly controlled by precipita-tion,followed by the impact of temperature.The Mann-Kendall test showed that the variation of average discharge had a mutation point in 2009.Although the evaporation from 1973 to 1980 was at a high value,the evaporation from 1956 to 2003 showed a downward trend in general.The average wind speed was probably the main factor affecting evaporation.The moist index(precipitation/evaporation)showed an upward trend,indicating that the climate in Delingha is getting humid over the past 60 years.The rising areas of Gahai Lake,Tuosu Lake,and Qinghai Lake,as well as the increase in vegetation coverage in the Qaidam Basin,further confirm the humidification and warming of the climate on the northeast Qinghai-Xizang Plateau.