中文摘要：

利用甘肃黑河流域不同下垫面的近地面气象和辐射观测数据,对已有的12个晴天大气下行长波辐射参数化模型和8个云天模型进行比较。指出晴天情况下Idso模型和D illey＆Obrien模型最适用,但后者一定要进行系数校正,云天情况下Maykut模型误差最小。经过平均日变化分析表明,晴天模型能较好地抓住大气下行长波辐射的日变化特征,模拟结果在夜间出现较大负偏差主要是由于逆温现象引起的;云天的平均日变化特征不明显。针对模型在不同季节模拟性能不同,将盈科绿洲站点的数据集分成春夏和秋冬季节,分别得到晴天模型在相应季节的拟合系数。

英文摘要：

Several widely used downward atmospheric longwave radiation parameterizations for both clear-sky and all-sky were tested against 10-minutes measured data from four stations at different surfaces in Heihe River Basin,northwest China.It can be inferred from the result that the Idso clear-sky equation was in good agreement with the observed data in all stations,even without adjustment to the observations,while Dilley Obrien equation had the best result after being adjusted.Both equations were more sensitive to air temperature than water vapor pressure.Maykut equation was found best in cloudy-sky,but the simulated radiations didn＇t fit well with measured flux.The diurnal and seasonal variations of downward longwave radiation were further studied.The predictions of Idso and Dilley Obrien equations showed the diurnal characteristics of downward longwave radiation under clear-sky conditions.The worst estimation of the model was before sunset,which was mainly caused by the temperature inversion phenomenon in the night.The longwave radiation had no obvious diurnal characteristic in the cloudy-sky days.For seasonal variations,both models had much better estimation in autumn-winter than spring-summer period,also the coefficients in each period were also obtained.Based on the results of this study Idso and Dilley Obrien equations were recommended for clear-sky days and Maykut model for all-sky when longwave radiation is calculated in a similar climate.