Impact of Soil Moisture Uncertainty on Summertime Short-range Ensemble Forecasts  

作　　者：Jiangshan ZHU Fanyou KONG Xiao-Ming HU Yan GUO Lingkun RAN Hengchi LEI 

机构地区：[1]Institute of Atmospheric Physics, Chinese Academy of Sciences [2]Center for Analysis and Prediction of Storms, University of Oklahoma [3]State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University

出　　处：《Advances in Atmospheric Sciences》2018年第7期839-852,共14页大气科学进展（英文版）

基　　金：supported by the National Key R&D Program on Monitoring, Early Warning and Prevention of Major Natural Disaster (2017YFC1502103);the National Natural Science Foundation of China (Grant Nos. 41305099 and 41305053)

摘　　要：To investigate the impact of soil moisture uncertainty on summertime short-range ensemble forecasts（SREFs）, a fivemember SREF experiment with perturbed initial soil moisture（ISM） was performed over a northern China domain in summertime from July to August 2014. Five soil moisture analyses from three different operational/research centers were used as the ISM for the ensemble. The ISM perturbation produced notable ensemble spread in near-surface variables and atmospheric variables below 800 h Pa, and produced skillful ensemble-mean 24-h accumulated precipitation（APCP24） forecasts that outperformed any single ensemble member. Compared with a second SREF experiment with mixed microphysics parameterization options, the ISM-perturbed ensemble produced comparable ensemble spread in APCP24 forecasts, and had better Brier scores and resolution in probabilistic APCP24 forecasts for 10-mm, 25-mm and 50-mm thresholds. The ISM-perturbed ensemble produced obviously larger ensemble spread in near-surface variables. It was, however, still under-dispersed, indicating that perturbing ISM alone may not be adequate in representing all the uncertainty at the near-surface level, indicating further SREF studies are needed to better represent the uncertainties in land surface processes and their coupling with the atmosphere.To investigate the impact of soil moisture uncertainty on summertime short-range ensemble forecasts（SREFs）, a fivemember SREF experiment with perturbed initial soil moisture（ISM） was performed over a northern China domain in summertime from July to August 2014. Five soil moisture analyses from three different operational/research centers were used as the ISM for the ensemble. The ISM perturbation produced notable ensemble spread in near-surface variables and atmospheric variables below 800 h Pa, and produced skillful ensemble-mean 24-h accumulated precipitation（APCP24） forecasts that outperformed any single ensemble member. Compared with a second SREF experiment with mixed microphysics parameterization options, the ISM-perturbed ensemble produced comparable ensemble spread in APCP24 forecasts, and had better Brier scores and resolution in probabilistic APCP24 forecasts for 10-mm, 25-mm and 50-mm thresholds. The ISM-perturbed ensemble produced obviously larger ensemble spread in near-surface variables. It was, however, still under-dispersed, indicating that perturbing ISM alone may not be adequate in representing all the uncertainty at the near-surface level, indicating further SREF studies are needed to better represent the uncertainties in land surface processes and their coupling with the atmosphere.

关 键 词：ensemble forecast soil moisture perturbation probabilistic quantitative precipitation forecast 

分 类 号：S152.7[农业科学—土壤学]