羌塘高原申扎高寒湿地辐射平衡和地表反照率特征

Characteristics of the radiation balance and surface albedo of a typical alpine wetland in Qiangtang Plateau

羌塘高原湿地能量交换过程及其作用结果对气候有着重要影响。本研究选择羌塘高原申扎地区典型高寒湿地的辐射平衡观测数据为基础,分析了2018-07—2020-07逐日、逐月、逐时、不同季节典型天气辐射各分量及逐日反照率变化特征。日尺度上,辐射各分量均表现出明显的季节规律,呈“U”型变化。6月向下短波辐射全年最大为301.1 W·m^(-2),平均温度最高,向上长波辐射也达到最大,为371.5 W·m^(-2),1月则相反。季节尺度上,短波辐射各季节平均值春季>夏季>秋季>冬季,长波辐射和净辐射则夏季最高,冬季最小。不同天气下,各季节晴天辐射通量较平滑,多云和降水天气变化不规则。地表反照率2018—2020年观测均值为0.23,夏、秋季小,冬、春季大,降雪天气甚至达到了0.63。研究结果可对揭示羌塘高原典型高寒湿地辐射收支的动态变化规律、阐明羌塘高原热力作用对其自身及周边地区的影响提供数据支撑。

The energy exchange process and its effects on wetlands in the Qiangtang Plateau have an important impact on the local climate.This study is based on the radiation data observed from June 2017 to June 2020 in Xainza-a typical alpine wetland located in the Qiangtang Plateau-and comprehensively analyzes the characteristics of seasonal,monthly,daily,and hourly weather radiation and albedo.The results show that all the radiation components present obvious seasonal“U”-shaped patterns.The maximum downward shortwave radiation is 301.1 W·m^(-2),and,in June the maximum upward longwave radiation is 371.5 W·m^(-2),yet the minimum of both appeared in January.Downward shortwave radiation,upward and downward longwave radiation,and net radiation all show obvious seasonal patterns,characterized by“U”-shaped changes.The hourly value of shortwave radiation in each season is the highest in spring,followed by summer and autumn,and the lowest is detected in winter.Longwave radiation and net radiation are highest in summer and lowest in winter.The radiant flux on sunny days in each season is relatively smooth,and the changes in cloud cover and precipitation are irregular;the average yearly surface albedo is 0.23,the lowest detected in summer and the highest in winter,reaching up to 0.63 on snowy days.These results can contribute to revealing the dynamic changes of the radiation budget occurring on the typical alpine wetland of Xainza,in the Qiangtang Plateau,and to clarifying the influence of such variation on the thermal effect.