部分云覆盖下红外辐射传输模型及对火山灰云的敏感性研究  

Study of an Infrared Radiative Transfer Model under Partially Cloud-Covered and Its Sensitivity to Volcanic Ash Cloud

作　　者：赵营营[1] 朱琳[2] 孙文彬[1] 李文杰[1] 

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [2]中国气象局国家卫星气象中心,北京100081

出　　处：《红外技术》2016年第4期348-355,共8页Infrared Technology

基　　金：国家自然科学基金"基于多源卫星数据的火山灰云质量浓度定量反演研究"(41201448)

摘　　要：针对我国新一代地球同步气象卫星FY-4的预期发射和数据应用,本文借助与FY-4卫星成像仪类似的Meteosat-8卫星的SEVIRI仪器数据资料开展先期研究,建立了一种部分云覆盖条件下红外辐射传输模型,模拟了不同大气条件、火山灰云高度、有效云量和观测天顶角情况下卫星观测的红外通道的亮度温度的变化。美国标准气候态大气廓线和火山灰区实时大气廓线两种模拟结果都表明,模型模拟的8.3~9.1μm,9.8~11.8μm,11~13μm,12.4~14.4μm的入瞳亮度温度对云高度、有效云量较为敏感,基本呈线性相关;卫星天顶角对模拟的辐射亮温的影响相对较小。通过不同大气廓线状态和火山灰云发射率情景下的测试结果表明,只有同时考虑大气条件和火山灰云通道发射率的差异后,模式才能够较好地模拟出火山爆发情景下火山灰云中酸性物质在11μm和12μm的反吸收特性。与大气条件相比,通道的发射率差异对火山灰云的遥感建模更为重要。因此,可在传统的分裂窗通道的基础上,通过热红外多通道亮温及亮温差异信息联合反演火山灰云高度和有效云量等因子,提高部分覆盖下火山灰云的微物理参数的反演精度。本研究为建立基于我国新一代静止气象卫星FY-4数据的火山灰云浓度定量反演模型提供了理论基础。Based on instrument spectral response characteristics of Meteosat-8 SEVIRI which is adopted as a proxy of the FY-4 Imager which will be launched next year, an infrared radiative transfer model under partially cloud-covered is established. Observed brightness temperatures of SEVIRI infrared spectral bands（with 8.3-9.1 μm, 9.8-11.8 μm, 11-13 μm and 12.4-14.4 μm, respectively） under different atmospheric conditions, volcanic ash cloud heights, effective ash cloud emissivity and observation zenith angles are simulated. We found that no matter whether under U.S. standard atmosphere or in-situ atmospheric condition, the simulated brightness temperatures always show high sensitivity to cloud heights and effective ash cloud emissivity. The relationship between simulated brightness temperatures and cloud heights, effective ash cloud emissivity is nearly linear. However, the effect of satellite zenith angle on the simulated brightness temperatures is relatively small. Further simulation tests under both different atmospheric profiles and volcanic emissivity conditions demonstrate that only when the atmospheric effect and channel emissivity are all taken into account, the mineral particles＇ reverse absorption effect in 11μm and 12μm in a volcanic eruption scenario can be simulated. Compared with the atmospheric conditions, the channel emissivity difference is more important for radiative modeling the ash cloud. Therefore, based on the traditional split-window temperature difference method, the joint use of multi-channel thermal infrared brightness temperature information can improve the retrieval accuracy of volcanic ash height and effective ash cloud emissivity under partial cloud-covered conditions. This study provides a theoretical basis on the establishment of quantitative volcanic ash inversion model for China＇s new generation geostationary meteorological satellite FY-4.

关 键 词：火山灰云 部分云覆盖 红外辐射传输模型 有效云量 火山灰云高度 亮温敏感性 

分 类 号：TP70[自动化与计算机技术—检测技术与自动化装置]