塔克拉玛干沙漠腹地净辐射变化特征

Research on Net Radiation Characteristics at the Hinterland of the Taklimakan Desert

利用塔克拉玛干沙漠大气环境监测站（塔中站）直接探测的辐射资料,计算了流动沙漠区近地层净辐射值,并对其变化特征进行分析。结果表明：净辐射的连续日变化对天气现象有不同程度的反映,1月天气现象较少,逐日净辐射上下变动的离散度较小,4月最大。沙漠区净辐射值并不大,要比同一季节中纬度裸地低。净辐射早晚两次改变符号,通过零值的时间约比日出落后40～60 m in,比日落提前60～90 m in。净辐射的极大值一般均出现在12：00时,有些月份出现在10：00时,极大值出现时,天空大多为云覆盖,但太阳未被遮蔽,大气透明度良好;负的极小值一般出现在少云天气的夜间。不同天气条件下净辐射有很大变化,但平均特征与晴天接近,白天晴天净辐射的值最高,而夜间晴天的值最低。

Based on the radiation data observed at Taklimakan Station for Atmosphere and Environment Observation and Experiment （Tazhong Station）, in this study the net radiation values near ground surface over the mobiledune area in the hinterland of the Taklimakan Desert were calculated and analyzed. The results show that the continued daily average variation of net radiation is related to the weather conditions in varying degrees, and the dispersion of daily net radiation fluctuation is low in January when weather changes infrequently, but it is the highest in April. The value of net radiation over the desert is not.so high, and actually it is lower than that over the nudation with the same latitude in the same reason. The net radiation becomes negative twice a day, and the negative values occur after sunrise for 40 - 60 minutes and before sundown for 60 - 90 minutes. The maximum value of net radiation occurs generally around 12 o＇ clock but around 10 o＇clock in some months when it is cloudy but the sun is not veiled entirely, and the air diaphaneity is high ; the minimum value of net radiation occurs generally at night when there are little clouds in the sky. The net radiation value is quite different under the different weather conditions, and its average is close to the net radiation value in sunny days. The net radiation value is the highest at daytime but the lowest at night in sunny days.