多源降水融合分析产品在重庆复杂地形下的精度评价

Study on Accuracy Evaluation of Multi-Source Precipitation Fusion Analysis Products under Complex Terrain in Chongqing

利用2020-2021年两套多源降水融合分析产品FAST和FRT产品、经过质量控制后的重庆地区35个国家气象站逐小时降水量资料,结合各站点地形因子对两套产品进行相关性和误差检验,为复杂地形下的水文气象研究提供数据支撑。结果表明:(1)FAST、FRT产品与观测值的相关性较好,呈正相关,误差较小,产品整体比观测值偏低,两者略有差别。(2)在月、季时间尺度上,春季的精度最好,汛期5-9月的误差和离散程度最大。(3)随着降水等级增大,产品的误差、相关性以及TS等级评分的分布越离散,误差绝对值逐渐增大,TS等级评分逐渐降低,相关性则先降低后增大,其中降水等级0.1~1.9mm、≥20mm的相关性较好。(4)在地形因子上,产品精度略有差别,其中斜坡上产品的精度最优,其余依次为平坡、陡坡以上和缓坡;起伏度大于70m产品的精度最优;随着海拔增加,产品精度先降低,当海拔大于700m时,产品精度提升;坡向为西南、东的产品精度更优,其中西南坡向最优。FAST和FRT降水产品在重庆地区具有较高的精度,可以为自动站点稀少地区的降水数据提供有效补充。

Two sets of multi-source precipitation fusion analysis products FAST and FRT products from 2020 to 2021, and the hourly precipitation data of 35 national meteorological stations in Chongqing after quality control were used to test the correlation and error of the two sets of products in combination with the topographic factors of each station, so as to provide data support for hydrometeorological research under complex terrain. Some results in this study showed that:(1) FAST and FRT products had good correlation with the observed value, positive correlation and small error. The overall product was lower than the observed value, and there was a slight difference between them.(2) On monthly and seasonal time scales, the accuracy of spring was the best, and the error and dispersion degree of flood season from May to September were the largest.(3) With the increase of precipitation grade, the distribution of product error, correlation and TS grade score became more discrete, the absolute value of error gradually increased, the TS grade score gradually decreased, and the correlation first decreased and then increased,among which the correlation of precipitation grade 0.1-1.9mm and ≥ 20mm was better.(4) In terms of terrain factors,the accuracy of products was slightly different, among which the accuracy of products on the slope was the best,followed by the flat slope, above the steep slope and gentle slope. The accuracy of products with undulation greater than 70m was the best;With the increase of altitude, the product accuracy decreased first. When the altitude was greater than 700m, the product accuracy increased. The accuracy of products with the Southwest and East slope directions was better, and the Southwest slope direction was the best. FAST and FRT precipitation products had high accuracy in Chongqing, which could effectively supplement the precipitation data in areas with few automatic stations.