基于CLDAS的格点温度预报偏差订正方法

Deviation Correction Method of Grid Temperature Prediction Based on CLDAS Data

利用国家气象信息中心CLDAS格点温度实况、中央气象台SCMOC格点温度预报以及山西省站点观测温度,采用非独立性检验综合评估CLDAS在山西区域的适用性。在此基础上,采用滑动训练期订正方案,基于格点实况开展SCMOC温度预报场的客观订正。结果表明:(1)复杂地形对山西CLDAS格点温度实况的精度有一定影响,但最高气温的分析精度优于最低气温,表明地形对最低气温的偏差影响更显著,高海拔地区CLDAS最低气温一般对应为负偏差,低海拔地区一般对应为正偏差。(2)CLDAS格点温度实况的偏差空间分布具有时间延续性,进行简单的系统偏差订正后,最高、最低气温格点实况的精度分别提升1.1%、9.7%,与站点观测更为吻合。(3)基于改进后的CLDAS格点温度实况,采用滑动偏差订正方案,显著改善了山西省SCMOC温度预报的准确率。2019年,滑动偏差订正后的24 h时效最高、最低气温预报准确率较SCMOC温度预报分别提升2.7%、4.7%,订正后的短期温度预报质量有较大提高,优于预报员主观预报。

Based on CLDAS grid temperature data from National Meteorological Information Center of China,SCMOC grid temperature forecast data from Central Meteorological Observatory of China and temperature observation data at weather stations of Shanxi Province,the applicability of CLDAS temperature in Shanxi Province was evaluated comprehensively by using non-independence test method.And on this basis,based on CLDAS grid temperature data,the objective correction of SCMOC temperature forecast field was studied by using the sliding training period scheme.The results are as follows:(1)The complex terrain in Shanxi Province had a certain influence on the accuracy of CLDAS temperature,and the maximum temperature of CLDAS exhibited a better accuracy than the minimum temperature of CLDAS,which indicated that the influence of terrain on deviation of the minimum temperature was more significant,and the deviation of the minimum temperature in high altitude areas was negative generally,while that in low altitude areas was positive.(2)The deviation of CLDAS grid temperature had a continuity of time in space.After the simple deviation correction,the accuracy of the maximum and minimum temperature of CLDAS promoted by 1.1%and 9.7%,respectively,the revised temperatures were more consistent with observation.(3)Based on improved CLDAS grid temperature,the accuracy rate of SCMOC temperature forecast improved significantly by using the sliding deviation correction scheme.Compared to SCMOC,the accuracy rate of the 24-hour maximum and minimum temperature forecast in Shanxi Province in 2019 respectively increased by 2.7%and 4.7%after the sliding deviation correction.The quality of short-term temperature forecast after the sliding deviation correction had greatly improved,and it was superior to the subjective forecast of forecasters.