散射计和下投式探空仪资料对台风模拟的影响

为了评估同化QuikSCAT海平面气压场资料和Dropsonde资料对台风"Bilis"和"Kat-rina"模拟的影响,通过WRF-3DVAR变分同化系统将QuikSCAT海平面气压场资料和Dropsonde资料同化到WRF模式中,并以未同化任何资料和同化了QuikSCAT海平面气压场以及同化了Drop-sonde资料的数据为初始场,应用WRF模式进行模拟预报,并对得到的初始分析场和模拟预报得到的结果与台风实况报文进行了对比,得到的结论是:对台风初始时刻海平面气压场分布、初始台风中心定位、台风初始暖心结构的改善、台风路径、海平面最低气压场、海面最大风速和雷达回波的模拟方面,同化QuikSCAT海平面气压场的效果比同化Dropsonde资料明显,其中二者对海平面最低气压场的改进效果比海面最大风速的要好。但是两种资料的同化对初始相对湿度和台风强度细节变化方面都没有产生明显改善作用。同化QuikSCAT海平面气压场试验虽然仅仅同化了单层海平面气压场,但是在三维变分同化系统的动力约束作用下,也可以影响到中高层的各个要素场。

The impact of scatterometer and dropsonde data on the numerical simulation of typhoons

To evaluate the impact of scatterometer and dropsonde data on the typhoon Bilis and Katrina simulation the sea surface pressure aboard QuikSCAT and dropsonde data are assimilated into WRF model by WRF-3DVAR variational assimilation system.Based on the initial fields without assimilating any data and with assimilating sea surface pressure aboard QuikSCAT or dropsonde data,the Bilis and Katrina typhoons are simulated by WRF model.And the obtained initial analyzed fields and the simulated results are compared with the typhoon report.The results show that the impacts of assimilating the sea surface pressure aboard QuikSCAT on the improving the initial value and forecasting the typhoon are more obvious than those of assimilating the dropsonde data,including the sea surface pressure distribution,the location of typhoon center,the warmer core structure at typhoon initial fields,as well as the simulated typhoon track,the lowest sea surface pressure,the largest sea surface wind speed and radar echo.And by assimilating both data the improvement in the lowest sea surface pressure field is more evident than that in the largest sea surface wind speed,however no effect on the relative humidity at the initial field and the detailed change of typhoon intensity can be found.Although assimilating sea surface pressure aboard QuikSCAT just involved monolayer sea surface pressure,due to the dynamical restriction process of WRF-3DVAR the effect can spread towards all element fields at the higher level.