【作者】 张治国；

【导师】 王振会；

【作者基本信息】 南京信息工程大学 ， 大气遥感科学与技术， 2012， 硕士

【摘要】 目前的“卫星导风”技术主要是以卫星云图上“云”和水汽图上的水汽作为示踪物追踪得到云区和水汽区的大气风场信息(称为“云导风”、“水汽导风”),进行导风的主要原理是在连续时间间隔三十分钟或一小时的二或三幅卫星红外图像或水汽图像上,通过模块相关性计算,搜索匹配的示踪模块,计算示踪模块的移动速度的大小以及方向,并以此代表相应高度上的大气风矢运动。然而,在卫星红外云图中存在的不能被识别为“云”的区域(本研究称其为“晴空区”),则不进行“云”目标的追踪匹配计算,因此,传统的“云导风”技术无法获得“晴空区”风矢信息。为进一步为气象应用提供数量更多、连续性更好的风向、风速资料,本文围绕利用静止卫星红外图像计算卫星云图“晴空区”大气风矢的目标开展研究,主要研究工作和结果如下：1、根据大气对辐射的选择性吸收特征,分析了在大气红外“窗区”谱段内的大气主要吸收气体对辐射的衰减特征和几种不同类型气溶胶粒子在大气红外“窗区”谱段内的折射指数差异特征,指出大气水汽以及气溶胶粒子在长波红外两“分裂窗”谱段内对辐射衰减的差异性,为从卫星观测得到的辐射量中提取“晴空导风”示踪信号提供了可能。2、结合FY-2E星载辐射计红外“分裂窗”通道的光谱响应函数特征,利用MODTRAN4大气辐射传输模式分别模拟计算了中纬度夏、冬季晴空大气条件下,卫星观测亮温度对大气水汽以及气溶胶光学厚度的敏感性；同时计算了满足星载辐射计红外观测通道0.2～0.5K不同温度灵敏度条件下进行“晴空导风”的示踪物应满足的条件。3、根据模拟计算获得的敏感性结果,分别利用FY-2E晴空大气可降水量产品和Terra MODIS MOD04L2大气气溶胶产品数据,分析了在实际大气中晴空区示踪模块内示踪物含量变化满足相应特征条件的可能性。(1)利用2010年FY-2E晴空大气可降水量产品分析了(15°N-50°N,70°E-140°E)区域范围内晴空大气水汽分布特征；(2)利用2009年03-04时(UTC)时间段内的Terra MODIS MOD04_L2产品数据分析了晴空大气溶胶分布特征,计算了所研究的空间或时间范围内的“有效示踪模块”占晴空模块总数的百分比月平均值。实例分析和统计计算的结果揭示了利用静止气象卫星红外云图计算大气晴空区风矢所需要的示踪模块条件能够被满足的概率估计值。4、利用“分裂窗”差值法进行了云图“晴空区”导风的实例分析,计算结果所获得的红外云图“晴空区”大气风矢与相应的NCEP850hPa高度的大气风场具有较好的一致性。更多还原

【Abstract】 The current techniques for atmospheric motion vector derivation from satellite images are mainly concentrated on cloud motion which uses cloud in IR imagery as tracer and water vapor motion which uses water vapor in water vapor imagery as tracer. The main theory is to search the matching tracer module from two or three continuous satellite images with half or one hour time interval and calculate the displacement of module to represent the atmospheric wind vector on corresponding altitude. If a region can not be identified as cloud-covered, the cloud-tracing technique would fail to obtain atmospheric motion vectors in this "clear" region with IR imagery.This paper is focused on retrieving atmospheric motion information in "clear regions" from geostationary satellite IR images to provide more wind materials with better spatial continuity for meteorological application. This work mainly includes the following four aspects:1、We analysis the attenuation characteristics of radiation and the refractive index difference characteristics of some different kind of aerosol particles in IR window spectrum region on the basis of atmosphere’s selective absorption characteristics of radiation. On this basis, we point out the atmosphere’s attenuation characteristics of radiation provide possibility for derive atmospheric motion vectors in clear region with IR imageries.2、On the basis of radiation transfer theory in IR window, we apply MODTRAN radiation transfer model to make sensitivity analysis on brightness temperature in thermal IR window channels with respect to water vapor and aerosol contents in the observation pixel, which might be used as tracers for deriving atmospheric motion wind vectors in clear atmosphere regions under middle latitude summer and winter atmosphere condition, by combination of atmospheric parameters and satellite-borne radiometer sensitivity performance. Additionly, we calculate the threshold value of tracer content change which could cause the difference of satellite-borne IR radiometer observation brightness temperature be greater than the different sensitivity of temperature (0.2-0.5K) in FY-2E borne radiometer IR channels. 3、We also carry out the feasibility analysis to ensure the existence of the tracer signals under certain conditions in real atmosphere by combination of the sensitivity results and data that includes FY-2E Atmospheric Total Precipitation Water products and Terra MODIS MOD04_L2Atmospheric Aerosol products. In addition, we calculate the monthly average percent of effective modules in total clear modules with FY-2E Atmospheric Total Precipitation Water products data in the region of (15°N～50°N,70°E～140°E) of2010and with Terra MODIS MOD04_L2Atmospheric Aerosol products data during the day time of03:00～04:00(UTC) of2009. The cases study and statistical analysis results reveal the estimated value to meet the required conditions for deriving atmospheric motion vectors in clear regions from IR imageries.4、We take a case analysis on retrieving atmospheric motion information in "clear" regions from satellite IR images with "split window" difference method and the calculate result shows a good consistency with the NCEP atmospheric wind on850hPa height.更多还原