夏季晴天不同土壤湿度条件的绿洲辐射特征

CHARCTERISTICS OF RADIATION OVER OASIS UNDER DIFFERENT SOIL MOISTURE CONDITIONS IN CLEAR DAYS SUMMER

利用2005年在甘肃省金塔绿洲开展的"绿洲系统能量与水分循环过程观测试验"所取得的资料,分析了夏季晴天金塔绿洲不同土壤湿度条件下的辐射收支特征。结果表明:向下短波辐射不受土壤湿度的影响;当植被处于同一生长期,土壤湿度越大,向上的辐射就越小,净辐射就越大;当空气中的水汽含量相差不大时,土壤较湿润则大气逆辐射白天较小,夜晚较大。但当水汽含量差别较大时,水汽含水量起主要影响作用,空气越湿润,大气逆辐射越小。

Under conditions of various soil moisture, characteristics of radiation budget over Jinta Oasis in clear days in Summer were discussed by using the data got from ＂The Oasis System Energy and Water Cycle Field Experiment＂ in Jinta Oasis of Gansu Province. Results showed that downward shortwave radiation is same when soil moisture was changed; under the condition that vegetations over the underlying surface were in the same growing period, bigger soil moisture with smaller upward radiation and bigger net downward shortwave radiation; when the difference of water vapor in air was small, wetter soil, smaller downward longwave radiation in the day and bigger at night; when the difference of water vapor in air is big, downward longwave radiation is big. There is smaller downward longwave radiation, with more moisture in the air.