FY-2C云迹风资料同化应用对台风预报的影响试验研究

Impact of Application of Cloud Motion Wind Data from FY-2C Satellite on Simulation of Typhoon Cases

针对0505号台风"海棠",采用WRF区域中尺度模式进行控制试验和两个同化试验,利用WRF-3DVAR同化系统同化FY-2C红外和水汽两个通道云迹风反演产品,同化分云迹风经质量控制和未经质量控制两组同化试验。通过三组试验分析云迹风资料对降水和风场等的预报结果的影响,并进行24小时降水量分级Ts评分检验以及风场点对点检验。结果表明:同化经质量控制云迹风资料可以提高降水落区和强度预报的准确度,不同等级的Ts评分较其它试验都有较明显改进;风场预报模拟也有所改善。增加两例台风,使用与"海棠"相似的处理方法进行模拟试验,并对模拟结果24小时降水分析与检验,得到与"海棠"类似结论。因此,经过合理性选择的云迹风资料的加入,有利于补充初始场中可能未包含的中尺度信息,从而提高试验中对于降水、风场等的模拟效果,提高WRF模式的模拟预报能力。

The control experiment and two assimilation experiments of WRF regional mesoscale model prediction are verified for typhoon Haitang （0505）. Based on the WRF-3DVAR system, the FY-2C infrared and water vapor cloud motion winds are assimilated into WRF model. The assimilation data of one assimilation test are the cloud motion winds before quality control and those of the other are cloud motion winds after quality control. The effect of the cloud motion winds on the prediction of rain and wind field is analyzed through comparing the three tests. Results show that the assimilation of the quality-controled cloud motion winds into the initial fields has positive impact on prediction of the area and intensity of rain, and also indicate that different grades of Ts score are improved by far than the other tests. The assimilation makes improvement in the forecast of wind. The same approach as that for Haitang is taken to simulate other two typhoon cases and the Ts scores of the forecast rainfall are given. And the results for the two typhoon cases show similar conclusions. Therefore, assimilating cloud motion winds with reasonable control and selection can well improve the descriptive possibility of wind field in WRF model, supply the mesoscale information in the initialization field to improve the simulation result of precipitation and wind field and have positive impact on the forecasting ability of WRF model finally.