FY-4A星地面太阳辐射产品检验与订正——以安徽省为例

VERIFICATIONS AND CORRECTIONS OF SURFACE SOLAR RADIATION PRODUCTS FROM FY-4A SATELLITE——As a Case Study in Anhui Province

基于FY-4A星反演的地面太阳入射总辐射(以下简称反演总辐照度)、云检测产品,合肥和屯溪站地面观测总辐照度(以下简称观测总辐照度)、地面相对湿度、水平能见度数据,在对比不同时间尺度反演和观测总辐照度异同的基础上,分析可能导致反演偏差的相关气象因素,进而对反演总辐照度进行订正,结果表明:反演与观测总辐射均表现出中午高早晚低,夏季高冬季低的特点,反演总辐照度整体较观测偏高约200 W/m^(2);逐小时数据对比中,两者绝对偏差在上午和下午各有一个峰值,而相对偏差在中午前后较低,早晚相对较高;逐日和逐月数据上绝对偏差在多数情况下与平均偏差接近,相对偏差整体上冬季高于夏季;反演总辐照度与观测值逐小时和逐日变化上均存在显著的正相关关系,但该关系在一定程度上受天气状况的影响;分析发现,地面相对湿度、水平能见度和FY-4A中云检测产品与反演偏差关系密切;按观测总辐照度进行分档,分段消除系统偏差再进行订正,可明显提高订正效果,经多元线性回归订正方法对合肥和屯溪逐时数据进行订正后两站反演总辐照度与观测值之间绝对偏差分别为60.85和58.11 W/m^(2),相对偏差为15.44%和15.02%,订正后反演总辐照度与观测值的相关关系得到进一步提升,相关系数分别为0.94和0.96;利用多元线性回归对反演的日平均总辐照度进行订正后,与观测值之间的平均相对偏差分别为11.75%和10.93%。

Based on retrieval of surface total solar incident radiation(hereinafter referred to as retrieval of total irradiance)and cloud detection products from FY-4A satellite,surface observation of total irradiance,surface relative humidity and horizontal visibility data at Hefei and Tunxi stations,the related meteorological factors which may lead to retrieval deviation are analyzed by comparing the retrieval and observation data at different time scales.Then the retrieval of total irradiance are corrected.The results show that:both the inversed and observed total radiation represent characteristics that are high at noon while low at morning and evening,and high in summer while low in winter.The retrieval of total irradiance are about 200 W/m^(2) higher than the observations on the whole.In hourly data comparison,absolute deviations of the two have a peak value in the morning and afternoon respectively,while the relative deviations are lower around noon and higher in the morning and evening.In daily and monthly data comparison,absolute deviations are close to average ones in most cases,while relative deviations are higher in winter than in summer generally.There are significant positive correlations between inversed and observed values both in hourly and daily variation,but the relationships are affected by weather conditions to a certain extent.It is analyzed that surface relative humidity,horizontal visibility and cloud detection products from FY-4A are closely related to retrieval deviations.It can be classified according to the observed total irradiance that subsection elimination of system deviation and correction can significantly improve the effect of revision.The absolute deviations of these two stations are 60.85 and 58.11 W/m^(2) respectively,and the relative deviations are 15.44% and 15.02% after the hourly data are corrected by multiple linear regression method.The correlation between the corrected retrieval total irradiance and the observed values has been further improved with their coefficients are 0.94 and 0.96 for both stations.Otherwise,the averaged relative deviations are 11.75% and 10.93% by multiple linear regression method in daily mean time scale.