利用FY-3星载微波资料对热带气旋云系和暖核特征的分析

介绍了中国FY-3系列卫星搭载的微波遥感仪器性能特点,以“1109”超强台风“梅花”为研究个例.通过微波湿度计单通道微波图像和微波成像仪双极化通道散点图,分析了台风云系中云雨粒子对遥感通道辐射的吸收和散射效应,揭示了台风在微波图像上表现形式的内在物理原因.利用微波向量辐射传输模式的模拟表明:微波温度计各氧气吸收通道对热带气旋系统水汽和水凝物含量变化的敏感性不大.因此,可利用权重函数峰值位于对流层中上层的通道3,探测出台风暖核辐射信息.根据两者相匹配的5个较理想时次数据,选取距“梅花”中心400 km范围为研究区域,并提出用于修正扫描点分辨率不均匀所带来取样偏差的方法,分别计算出订正临边效应后的暖核强度,发现它同表征台风强度的中心海平面气压变化趋势相一致.

Analysis of tropical cyclone spiral cloud and warm core characteristics with FY-3 satellite microwave data

After introducing the characteristics of microwave instruments flown aboard FY-3 series satellites, this paper focuses on "1109" super typhoon Muifa, analyses the absorbing and scattering effects of cloud and rain drops in typhoon spiral cloud, with the MicroWave Humidity Sounder single channel microwave image and MicroWave Radiation Imager dual-polarization scatter map, and reveals the physical reason of typhoon pattern's representation on microwave image. The simulation of the effects of water vapor as well as hydrometeors in the environment of tropical cyclone on the MicroWave Temperature Sounder observation is conducted with the vector discrete-ordinate radiative transfer model, very little sensitivity at oxygen absorption band is found. Therefore, with the weighting function peak near the middle-upper troposphere, the MWTS channel 3 is used to analyze the warm core characteristic. After mapping with typhoon best track, five ideal sets of data are selected, a proposed algorithm is devised to try to correct the bias from receiving warm core microwave radiation due to the uneven distribution of footprints,and the warm core intensity is computed in the 400 km researching area respectively, showing similar time-variant tendency to the minimum sea level pressure as described by the typhoon report.