TRMM/TMI资料在热带气旋强度估计中的应用研究

Estimating tropical cyclone intensity by using TRMM/TMI data

利用2007—2009年热带降雨测量卫星(TRMM)的微波成像仪(TMI)观测到的亮温资料,计算9个通道(10、19、37、85 GHz的水平和垂直极化通道及21 GHz的垂直极化通道)的亮温和极化修正温度(PCT)在不同范围内的最大值、最小值、平均值和区域阈值与热带气旋强度之间的关系。结果表明:亮温信息可较好地反映热带气旋的强度,单个参数与热带气旋最大风速的相关性最好可达到0.83,线性拟合的均方根误差接近业务误差;低频通道的亮温相对于高频通道可更好地估计海上热带气旋强度;位于台风中心0.5°～1.5°度范围之间的亮温与气旋强度的相关性较好,圆形区域的相关性好于圆环区域;对于位于海上的热带气旋,区域亮温的最小值与热带气旋强度的关系最好;低频通道(除10 GHz外),阈值位于260～280 K区间的亮温与热带气旋强度的相关性较好。

Using the brightness temperature（TB） data of TRMM Microwave Imager（TMI） from 2007 to 2009,we calculated the maximum,minimum,average values and the ratio of pixels over the threshold（AREA） in different regions of the TB and polarization correction temperature（PCT） from 9 channels（10,19,21,37 and 85 GHz channel）,and investigated the relationship between the TB and the Tropical Cyclone（TC） intensity.The results are as follows.The TC intensity may be well reflected by TB data,and the highest correlation coefficient can reach 0.83,and the linear fitting root mean square error is close to business error.TB from low frequency channels is better than that from high frequency channels to estimate the TC intensity on sea.The TB in the area from 0.5°to 1.5°latitude away from the TC center give higher correlation with TC intensity,and the correlation in circular area is better than that in the ring area.For TC on the sea,the minimum value of TB has the best correlation with the TC intensity.For the low frequency channels,except for 10 GHz,the TB threshold value from 260 K to 280 K gives higher correlation with the TC intensity.