敦煌湖泊湿地生态系统地表辐射平衡特征

Variations of the Components of Radiation in Desert Wetland of Dunhuang,China

利用2013年干旱环境背景下敦煌湖泊湿地生态系统的辐射数据,分析了该地区的辐射变化特征。结果表明:不同的天气背景,各辐射分量的日变化过程差异较大,晴天变化曲线呈平滑的单峰型,多云天气平滑度不如晴天,阴天、雨天和沙尘天气呈现了不规则的多峰型变化;各季辐射通量的日变化都呈单峰型,但收入量差异较大,极值出现的时间也不相同。向下短波辐射、向上和向下长波辐射、净辐射月总量的变化表现出明显的季节性,夏季>春季>秋季>冬季,向上短波辐射的月总量的季节变化不太明显。各辐射分量日平均值具有明显的季节性,夏、春季较大,秋、冬季较小,最大值出现在6月或7月,最小值出现在12月或1月。生长季的地表反照率要低于非生长季,各季日平均反照率都是早晚高,中午低,呈"U"型。

The characteristics of radiation on the Xihu wetland ecosystem of Dunhuang are analyzed by radia- tion data from the measurements of observation system in 2013. The results show that the daily variations of the radiation components are different under different weathers. The daily variation curves are smooth on sunny day, but on cloudy day and dust the curves become irregular. The diurnal variations of the radiation flux are unimodal type, but the radiation components volume variances are different and the extremes appear in different times. The seasonal variation characteristics of monthly total downward shortwave radiation, downward long-wave radiation, upward long-wave radiation and net radiation are obvious： the maximum val- ue appears in summer, and the minimum value appears in winter. However, the seasonal variation charac- teristics of monthly total upward shortwave radiation are not obvious. The daily mean of downward short- wave radiation, upward shortwave radiation downward long-wave radiation, upward long-wave radiation and net radiation has seasonality： the maximum value appears in June or July and the minimum value appears in January or December. The surface albedo in the growing season is lower than in the non-growing season. The diurnal variation of surface albedo is ＂U＂ shape, with the maximum value in the morning and evening.