红外超光谱资料(AIRS)反演“云娜”台风外围晴空大气温度廓线的研究

RETRIEVAL OF CLEAR SKY ATMOSPHERIC SOUNDING PROFILE AROUND TYPHOON RANANIM USING INFRARED HYPERSPECTRAL MEASUREMENTS AIRS

研究反演了2004年8月11日"云娜"台风附近晴空像元大气温度、臭氧廓线及表层温度、地表气压、地表比辐射率等参数,并与观测资料进行了对比验证。在研究了用高空间分辨率的MODIS成像仪的云检测信息来进行空间匹配,客观确定高光谱大气垂直探测器AIRS的云检测的基础上,用特征向量统计法反演的廓线作为物理反演法的初始猜值,然后利用牛顿非线性物理迭代法求解表层温度、表层气压、大气温度廓线和臭氧廓线等,并将反演结果与多种观测资料进行了对比验证。结果表明,反演得到的廓线水平分辨率可达到13.5 km(星下点),垂直分辨率达到101层,反演误差较小,可以弥补高原、沙漠以及高原等地方常规观测资料的不足。

The study retrieves the atmospheric profiles of temperature, moisture and ozone, together with surface emissivity and surface temperature and surface pressure from measured infrared sounder radiances under clear sky （cloudless） conditions, and validates them against the observations. Spatial matching is done to measured cloud information obtained from the high-spatial resolution imager（MODIS）. And then on the basis of cloud measurements from a high-spectral resolution atmospheric infrared sounder（AIRS）, profiles retrieved via a statistical eigenvector regression retrieval algorithm are used as the first guess for a physical retrieval method. Single term variational analysis is applied to the Radiative Transfer Equation（RTE） to first obtain an iterative form for temperature and water vapor mixing ratio weighting functions, then the Newtonian nonlinear iteration method is applied to the RTE to retrieve simultaneously profiles and surface values among others. The retrieved values are then compared with the observations. For the places where observations are very sparse such as the plateaus, deserts, the results show that the retrieved atmospheric sounding profile that is 13.5 kin（nadir） for horizontal resolution and 101 levels for vertical section can be used to makeup the lack of observations in the plateaus and deserts.