利用风云三号微波成像仪资料遥感“桑达”台风降雨云结构

Remote sensing typhoon Songda′s rainfall structure based on Microwave Radiation Imager of FY-3B satellite

本文利用搭载于我国风云三号B星上的微波成像仪(MWRI)观测亮温数据,结合戈达德廓线反演算法,对1102号"桑达"台风地面雨强和降雨云结构进行反演试验.利用AMSR-E业务降水产品对地面雨强反演结果进行了检验,结果表明,MWRI和AMSR-E反演的地面雨强在空间分布上非常吻合,相关性达76%,均方根误差约2.8mm/h,二者的观测亮温及地面雨强反演结果具有较好的一致性.提取洋面台风雨区的平均水凝物廓线,其垂直结构显示,雨水和可降冰含量丰富,随高度变化明显,且具有明显峰值高度,云水和云冰含量则较少,且随高度变化不明显;当降水增强时,雨水和可降冰各层含量稳定增加,且峰值高度基本保持不变,云水和云冰含量则增幅不稳,且峰值高度有所改变.地面雨强随距台风中心距离的变化阐释了台风的螺旋结构及降水特点,距台风中心距离0.3°和0.6°附近分别出现了地面雨强峰值和次峰值,且66%的降水集中在距台风中心距离1°的空间范围内.MWRI提供的台风地面雨强和降雨云垂直信息具有较高的可信度,对于我们监测台风降水、分析台风降水结构的时空演变特征以及数值预报模式应用等具有重要的参考价值.

Microwave Radiation Imager（MWRI） observations of FY-3B satellite were used to retrieve typhoon Songda′s rainfall structure in this paper based on Goddard Profiling Algorithm（GPROF）.The retrieved rainfall rate was validated using AMSR-E rainfall product.Results show that spatial distribution of rainfall rate from MWRI fits in with AMSR-E product with a correlation of 76% and a root-mean-square error of 2.8 mm/h.These two rainfall products and brightness temperature observations are very similar.Vertical profiles of four hydrometers（rain water,cloud liquid water,cloud ice water and precipitable water） are retrieved simultaneously.From the average profile of oceanic typhoon rainfall area,contents of rain water and precipitable ice,with peak height at 1 km and 6 km respectively,vary with height obviously;contents of cloud liquid water and cloud ice water are much less than that of rain water and precitable ice,and vary with height lightly.Results from average profiles between different parts of rainfall rate show that the contents of rain water and precipitable ice increase stably with an unchanged peak height,different from variations of cloud liquid water and cloud ice water.Spiral structure and precipitation characteristics of typhoon Songda are interpreted by analyzing variations of rainfall and contents of hydrometers with distance from typhoon eye.Peak and second peak rainfall occurred at distances of 0.3° and 0.6° from typhoon center respectively,and 66% rainfall amount distributed within distance of 1° from typhoon eye.In conclusion,MWRI can provide reasonable results of rainfall rate and hydrometeor profiles,which are of important reference significance for monitoring typhoon,analyzing typhoon′s spatial and temporal evolution and application in numerical prediction model.