淮河流域农田光合有效辐射(PAR)的基本特征

为了解淮河流域农田下垫面光合有效辐射的基本特征，分析淮河流域农作物生长的光、热条件，本文利用寿县国家气候观象台（32°30.83′ N，116°46.47′ E）2008年全年太阳辐射观测资料，采用30 min平均，按照线性关系y=cx做最小二乘拟合，得到PAR、RS以及PAR/Rs的日、月和季节均值，分析了该地区光合有效辐射（PAR）的日、季、年变化特征及所占太阳短波辐射（Rs）比例的一些基本特征，得出了该地区的光合有效辐射（PAR）的年总量为1970.8 MJ/m2，春、夏、秋、冬季的平均日总量分别为：6.83 MJ/m2、6.58 MJ/m2、4.28 MJ/m2、3.80 MJ/m2；得出了月平均PAR/Rs的值在0.37~0.43之间，最大值出现在夏季为0.43，最小值出现在冬季为0.37，年平均值为0.40；分析了晴天和阴天日PAR的变化有明显的区别，阴天日PAR/Rs的值比晴天日明天偏大，全年典型阴天日PAR/Rs的值为0.42，典型晴天日PAR/Rs的值的为0.39。对于PAR/Rs，云、水汽、太阳阳辐射强度以及大气浑浊度对其都有影响。

Basic Features of Photosynthetic Active Radiation over Cropland in Huaihe Valley

The research based on the solar radiation observation data of the Shouxian National Climate Observatory （32° 30.83＇N,116° 46.47＇E） of the whole 2008 year.The research analyzed the features of the annual,seasonal and daily variation of PAR,and the ratio of the solar short-wave radiation （Rs）.The annual amount of PAR of the area was 1970.8 MJ/m 2.The average daily volume of spring,summer,autumn and winter respectively：6.83 MJ/m 2,6.58 MJ/m 2,4.28 MJ/m 2,3.80 MJ/m 2.The monthly average PAR/Rs value between 0.37 and 0.43,the maximum value was 0.43 in summer,the minimum value was 0.37 in winter,and annual average value was 0.40.Found the changes in PAR in sunny and cloudy days was significantly different,PAR/Rs values cloudy day bigger than the sunny day,PAR/Rs value was 0.42 in the typical cloudy day over the year,whereas PAR/Rs value was 0.39 in the typical sunny day.Clouds,water vapor,solar radiation and atmospheric turbidity had effects on PAR /Rs.