Abstract:

 Based on the measured data of the Bowen ratio-energy balance method（BREB）and radiation in Dingxi Arid Meteorology and Ecological Environment Experimental Station，Institute of Arid Meteorology，CMA，this paper analyses the characteristics of surface energy budget and radiation under different types of synoptic condition sand averaged climatic conditions in spring wheat farmland.The results show that：（1）The characteristics of daily variations of the surface energy budget，the global radiation，the net radiation，the direct radiation and the atmosphere diapha neity coefficient（P2）are quite similar in the different growth stages of spring wheat under a clear day condition，but se values are distinct，these values increased gradually with growth stages of spring wheat；（2）The daily variation of the Bowen ratio is quite similar in different growth stages of spring wheat under a clear day condition.The Bowen ratio of night is bigger than that of daytime，and also the Bowen ratio of antemeridiemis bigger than that of afternoon. The Bown ratio is less than 1.0 in daytime.The biggest Bowen ratio occurs at 3~4P.M.in a day.In the whole growth stages，the Bowen ratio is gradually increscent，the  latent heat plays a leading role，and the sensible heat depends on the latent heat；（3）Under different types of synoptic conditions including a clear day and a cloud day，not only the farmland surface energy obtained is variable in magnitude，but the available energy admeasure disdifferent.The daily-integral values of global radiation，net radation under a cloud day is about 30%~40%less than those under a clear day.The range of variation in sensible heat flux and latent heat flux is about 15%between a cloud day and a clear day

Key words: Gansu province, dryf armland, energy budget, radiation

摘要：

利用在甘肃中部旱作农田多年积累的波文比能量平衡及辐射观测资料，分析了平均气候状态及不同天气状况下旱作春小麦农田不同生育期的辐射能量变化特征。结果表明：1）在晴天状况下的旱作春小麦农田，能量平衡各分量、总辐射、直接辐射、大气透明度系数P2等项中，每个要素在不同生育期的日变化趋势都是相同的，但是在量值上却存在差别，一般都是随着春小麦生育进程的变化而逐渐增大；2）在春小麦各生育期内，晴天波文比的日变化趋势相同。波文比值夜间大于白天，白天上午又相对大于下午，一日中波文比的最小值出现在下午3~4时左右。从整个生育期来说，波文比随生育进程的变化而逐渐增大，但是潜热交换一直居于主导地位，而感热输送只是处于从属地位，白天波文比总是<1；3）晴阴天不同天气状况下，农田地表获得的能量在量值上存在差别，阴天时总辐射、净辐射的日总量值一般为晴天时的30%~40%，可利用能量的分配规律在不同天气状况下不同，晴阴天潜热与感热的变幅约在15%。

关键词: 甘肃中部, 旱作农田, 能量收支, 辐射