数值预报在青藏高原的不确定性对其下游预报的影响  

The Numerical Prediction Uncertainties of the Tibetan Plateau Impacting the Forecasts of Its Downsteam Region

作　　者：张宇[1,2] 陈德辉 仲跻芹[4] 

机构地区：[1]南京信息工程大学,南京210044 [2]中国气象科学研究院,北京100091 [3]国家气象中心,北京100091 [4]中国气象局北京城市气象研究所,北京100142

出　　处：《高原气象》2016年第6期1430-1440,共11页Plateau Meteorology

基　　金：科技部973重大基础研究项目(2013CB430106);公益性行业(气象)科研专项(GYHY201406012);国家自然科学基金项目(91437221)

摘　　要：通过NCEP全球预报在不同地区的预报误差分析、包含大地形(亚洲青藏高原、北美落基山脉)与否的区域模拟试验、同化青藏高原地区人造观测的观测系统模拟试验,探讨了数值预报在青藏高原地区的不确定性对其下游地区预报的影响。结果表明:(1)数值模式在青藏高原地区的不确定性包括模式本身的动力与物理过程不确定性以及模式初值的不确定性,这种不确定性引起的预报误差会制约青藏高原下游地区预报性能;(2)若数值模拟区域不包含青藏高原地区,可避免青藏高原地区的模式不确定性引起的预报误差对下游地区的影响,提高下游地区预报技巧;(3)同化青藏高原地区"人造"加密观测资料,可有效减少数值预报在青藏高原地区的初值不确定性,进而减小青藏高原本区及其下游地区的预报误差、改进预报水平。The influence of the initial uncertainties on the NWP forecasts over the Tibetan Plateau（ TP） and adjacent regions was studied based on the GFS forecasts / WRF model and OSSE experiments. The result shows that：（ 1） The large uncertainties of Tibetan Plateau（ TP）,because of the scarcely observations and complex terrain,can affect the NWP forecasts over the TP region and decrease the forecast skill of the downstream region of TP. After comparing the forecast errors over the TP and the downstream regions,it is found that the errors over the TP region are larger than the errors over the TP adjacent / Pacific Ocean and Rocky Mountain regions on the first 24 hours’ integration： the error amplification rate over the TP adjacent region are larger than other regions evidently.（ 2） The forecast error rise faster over the downstream of TP region than the downstream of the Rocky Mountain（ US）. The WRF model forecasts results,with / without the large terrain（ TP / Rocky Mountain）,indicate that the forecast errors over the downstream region of the TP / Rocky Mountain are larger if the model domain contains the large terrain areas： this error divergence significantly after 2-days integration.（ 3） The observation data over TP region have effect on the forecasts of the downstream areas： additional ＂synthetic＂observation data can decrease the initial uncertainties over the TP region and then improve the forecast skills over the downstream of TP region. Therefore,this study suggests that in order to reduce the initial uncertainties influence over the TP region,the additional observations even the ＂synthetic＂observations over the TP region could assimilated to the NWP model.

关 键 词：青藏高原 模式不确定性 初值不确定性 观测系统模拟试验 

分 类 号：P435.1[天文地球—大气科学及气象学]