摘要
利用WRF-3DVAR系统同化常规探空资料及成都4个GPS测站的可降水资料,对2008年9月23～25日一次川西暴雨进行一系列同化试验。结果表明,选用合理的物理过程、积分步长和初始条件,WRF模式可以较好地模拟此次暴雨过程;同化可以改善暴雨落区和强度的预报,同化GPS可降水资料可有效地调节局地及水汽输送下游地区暴雨预报,对北川地区的强降水中心强度及位置预报较好,同化探空资料对雨带形状描述接近实况;同化GPS可降水资料对初始场的湿度场影响明显,而对其他变量场的影响相对较弱;2种资料的单独及同时同化,都改善了预报场的动力结构(垂直速度),有效地减少了spin-up时间,使得模式在积分初期就能模拟出与实况相近的动力结构;同化试验的温度预报场随时间误差增大,这可能与降水的触发有关。
A 3-dimensional variational assimilation and CTRL test were carried out on the rainstorm in western Sichuan which happened in September 23-25,2008 based on the data supplied by conventional sounding data sets and 4 GPS stations in Chengdu. The results showed that WRF mode can simulate the process of this rainstorm well if a reasonable physical process,integration step and initial condition were chosen. Assimilation could improve the forecast quality of the heavy rain area,the forecast of intensity and a single GPS data assimilation,supply a good description of heavy rainfall center in the downstream areas in Beichuan,and it also can effectively adjust the forecast of heavy rainfall at the local and the downstream areas of the water vapor transport,the description of the rain belt shape supplied by the assimilation sounding data is fair. The GPS data has a significant impact for the humidity field of the initial field,while the impact to other fields is weaker compared with sounding data. Both respective and simultaneous variational assimilation improved the dynamic structure of forecast fields （vertical speed）,reduced the spin-up phenomenon,enabled the mode to modify a dynamic structure which is similar to the real condition in the integral initial stage; the temperature forecast field of the assimilation test may increase with the root-mean-square error of time,which may be related to the trigger of the rainfall.
出处
《安徽农业科学》
CAS
北大核心
2010年第13期6759-6764,共6页
Journal of Anhui Agricultural Sciences
基金
2009年度公益性行业(气象)科研专项
关键词
三维变分同化
川西暴雨
GPS可降水量
探空
WRF
3-dimensional variational assimilation
Rainstorm in western Sichuan
GPS precipitation
Sounding
WRF
