基于NCEP FNL资料的山西岢岚地区雨雪天气诊断可信度分析

Confidence analysis of rainy and snowy weather diagnosis in Kelan,Shanxi province based on NCEP FNL data

基于山西岢岚地区2005—2014年共1218个雨雪天气日的NCEP FNL资料(1°×1°)与探空资料,采用偏差、绝对差、相关系数和偏差区间占有率的统计方法,对常规物理量(温度、相对湿度、纬向风和经向风)和诊断物理量(T_(800-500)、T_(d800)和TT_(d700))进行统计分析。结果表明:常规物理量中的温度平均偏差值和绝对差值最小、相关系数值最大,分别为-0. 22℃、1. 02℃、0. 90,可信度最高;而相对湿度的平均偏差值和绝对差值最大、相关系数值最小,分别为12. 31%、19. 68%和0. 63,可信度最低;纬向风和经向风的可信度相差不大,略低于温度;诊断物理量T_(800-500)、T_(d800)和TT_(d700)的偏差值分别为-0. 08℃、1. 50℃和2. 79℃,绝对差值分别为1. 21℃、3. 33℃和4. 14℃,相关系数值分别为0. 95、0. 92和0. 74,偏差值为[-5,5]占总数百分比分别为98. 77%、80. 30%和75. 04%。即T_(800-500)可信度最高,TT_(d700)指数可信度最低。

Based on the National Centers for Environment Prediction (NCEP) FNL Reanalysis data (1°×1°) and radiosonde data on a total of 1218 rainy and snowy days from 2005 to 2014 in Kelan,Shanxi province,the conventional physical variables (temperature,relative humidity,zonal wind and meridional wind) and diagnostic physical variables ( T 800-500 , T d 800 and TT d 700 ) were statistically analyzed based on statistical analysis methods including deviation,absolute difference,correlation coefficient,and the occurrence rates of deviation range.The results showed that among these conventional physical variables,air temperature has the lowest averaged deviation and absolute difference and the highest correlation coefficient,being-0.22 ℃,1.02 ℃,and 0.90,respectively,which means air temperature has the highest reliability.While relative humidity has the lowest reliability with the largest averaged deviation and absolute difference and the smallest correlation coefficient,being 12.31%,19.68%,and 0.63,respectively.The reliability of the zonal wind and meridional wind is close to each other and slightly lower than that of air temperature.For these diagnostic physical variables,the deviations of T 800-500 , T d 800 and TT d 700 are -0.08 ℃,1.50 ℃,and 2.79 ℃,respectively,and their absolute difference are 1.21 ℃,3.33 ℃,and 4.14 ℃ with the correlation coefficient of 0.95,0.92,and 0.74,respectively.The occurrence rates of deviation range between-5 and 5 are 98.77%,80.30%,and 75.04%,respectively.The reliability of T 800-500 is highest and that of TT d 700 is the lowest.The characteristics of the NCEP FNL reanalysis data on rainy and snowy days should be paid attention.