探空气球漂移位置订正在MM5模式中的应用研究

Study on the Positioning of Sounding Balloon Drifting in MM5 Model

通过对模式MM5V37中客观分析系统加以改进,并采用包含有实际探空气球在各个气压层上精确的经纬度信息的新型探空资料,加以研究探空资料随高度的漂移对高分辨率中尺度数值模式MM5V37的影响。通过对一次层状云降水个例的模拟可看出:位置订正所带来的初始场差异在低层较小,高层较大,且在500 hPa以上较明显;位置订正对模拟的气象要素场的修正有明显的正面效果,对强降水天气系统的反映比较敏感;模拟结果对于雨区分布和强降水中心的位置有较大改进;位置订正后的评分总体优于不加探空和不加漂移的评分,随着模式分辨率的提高,位置订正后对小量级降水的模拟效果欠佳,但对大量级降水的模拟效果较好。

In order to analyze the impact of height-depending sounding balloon＇s drifting on mesoscale numerical model （MMSV37）, the objective analysis system of MM5 is improved using the new sounding data with accurate position message at each pressure level. Through the simulation of a stratiform cloud precipitation, we can conclude as follows： Firstly, the differences of initial fields caused by position correction are greater in upper layers than in lower layers, and become more obvious above 500 hPa. Secondly, the position correction can better the meteorological element fields and that is more sensitive to evere pre- cipitation weather system and besides, the distribution of precipitation and the center of heavy rain are obviously bettered; Lastly, after the position correction, the scores are higher than other schemes, and as the resolution is rising, the position correction will better the high rainfall grads but not the low rainfall grads.