The Capability of Atmospheric Profile Retrieval from Satellite High Resolution Infrared Sounder Radiances

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红外高光谱资料模拟大气廓线反演对云的敏感性

用不同云顶高度和不同有效云量时的星载红外高光谱观测值,模拟大气温湿垂直廓线反演对云参数的敏感性。用特征向量统计反演法按照云顶高度和有效云量分类反演了大气温湿廓线,统计了不同云高（200,300,500,700和850hPa）及云高有50hPa误差时温度、水汽混合比反演的均方根误差随有效云量的变化。结果表明,随着有效云量的增大,云顶以下各高度层上的温度、水汽混合比反演误差都明显增大。云高有50hPa误差较准确已知而言,温度和水汽混合比的反演误差增大,但温度反演对云高误差的敏感性比水汽反演要高。     

AIRS资料反演大气温度廓线的通道选择研究

通过引入信息容量的概念,给出了一种对高光谱大气探测资料所包含各种大气参数有效信息进行描述的方法;然后以信息容量为指标,设计了利用"逐次吸收法"进行通道选择的计算方案;最后针对利用大气红外探测器(AIRS Atmospheric Infrared Sounder)探测资料反演大气温度廓线进行了通道选择试验.从将本文试验选择结果与NASA(National Aeronautics and Space Administration) DAAC(Distributed Active Archive Center)进行AIRS产品反演时所使用通道进行比较的结果表明,利用信息容量为指标,并按照"逐次吸收法"进行通道选择是可行的.     

Preliminary Study on Direct Assimilation of Cloud-affected Satellite Microwave Brightness Temperatures

Direct assimilation of cloud-affected microwave brightness temperatures from AMSU-A into the GSI three-dimensional variational(3D-Var) assimilation system is preliminarily studied in this paper. A combination of cloud microphysics parameters retrieved by the 1D-Var algorithm(including vertical profiles of cloud liquid water content, ice water content, and rain water content) and atmospheric state parameters from objective analysis fields of an NWP model are used as background fields. Three cloud microphysics parameters(cloud liquid water content, ice water content, and rain water content) are applied to the control variable. Typhoon Halong(2014) is selected as an example. The results show that direct assimilation of cloud-affected AMSU-A observations can effectively adjust the structure of large-scale temperature, humidity and wind analysis fields due to the assimilation of more AMSU-A observations in typhoon cloudy areas, especially typhoon spiral cloud belts. These adjustments, with temperatures increasing and humidities decreasing in the movement direction of the typhoon,bring the forecasted typhoon moving direction closer to its real path. The assimilation of cloud-affected satellite microwave brightness temperatures can provide better analysis fields that are more similar to the actual situation. Furthermore, typhoon prediction accuracy is improved using these assimilation analysis fields as the initial forecast fields in NWP models.     

Simultaneous Non-linear Retrieval of Atmospheric Temperature and Absorbing Constituent Profiles from Satellite Infrared Sounder Radiances

Based on Zeng’s theory (1974), a successive linearized form of radiative transfer equation (RTE) is derived for simultaneous retrieval of atmospheric temperature and absorbing constituent profiles from satellite infrared observa-tions. It contains the temperature component weighting function and absorbing constituent (H2O, O3, CH4 etc.) com-ponent weighting functions. All these weighting functions reach maximum at their own “optimum information levels”, and make the remote sensing equations well-conditional. Then the atmospheric profiles are derived by Newton’s non-linear iteration method. Experiments of retrieval from both TIROS-N operational High Resolution Infrared Sounder (HIRS) and the simulated Atmospheric infRared Sounder (AIRS) show an significant improvement.     

冷空气过程对黄海东海区域海洋大气边界层结构影响的个例分析

利用一次冷空气过程的14组GPS探空数据,采用位温梯度法确定了冷空气过境前后大气边界层高度,并分析了冷空气过程对大气边界层结构的影响。结果表明：冷锋过境加大了海洋大气边界层的静力不稳定度,使边界层内对流活动增强,且锋面过后距离锋面越近的区域边界层的静力不稳定度越大;冷锋过境使边界层的平均高度升高,边界层顶处逆温梯度增大。结合ERA-Interim再分析资料,分析认为大气边界层高度与静力稳定度（海气温差）存在显著的正相关关系（相关系数达0.73）,海气温差越大,大气边界层高度越高。     

利用MODIS红外资料反演大气温湿度廓线的研究

概述了利用特征向量统计回归反演算法,从EOS/MODIS的红外通道资料反演大气温湿度垂直分布的过程,并与美国国家环境预报中心NCEP(National Centers for Environmental Prediction)的等压面再分析场资料按照纬度和气压高度进行了真实性检验。结果表明：由MODIS资料反演得到的大气温湿度参数能够揭示大气温湿度的垂直分布。在各个等压面上均方根误差平均值在中纬度地区为3.39K,低纬度地区为1.40K,近地面层、对流层顶附近及下垫面地形复杂的区域误差较大,总体上低纬度地区要好于中纬度地区。反演的水汽误差也为低纬度地区小于中纬度地区,且随高度升高,中、高纬度误差都逐渐减小并逐渐接近。     

基于IASI双二氧化碳通道的一种不同高度云检测算法

利用红外高光谱探测仪（Infrared Atmospheric Sounding Interferometer,IASI）在二氧化碳吸收带的长短波红外通道对云反应程度的不同来探测云。依据不同通道的权重函数峰值高度和云不敏感层高度将IASI长短波红外通道进行配对,成功配对的长短波红外通道晴空亮温之间建立线性回归模型,即通过长波红外通道亮温可以线性回归得到配对的短波通道亮温,将短波通道的晴空回归亮温和观测亮温之差定义为云指数。权重函数峰值高度位于383 hPa的云指数空间分布和云成分为冰的空间分布较为一致,尤其在赤道和低纬度地区。权重函数峰值高度位于790 hPa的云指数空间分布和低云云顶气压也有较好的一致性。     

华东农田秸秆燃烧对常州大气环境的影响

为研究2012年6月6—15日华东农田秸秆燃烧对江苏省常州市大气环境的可能影响,利用中分辨率成像光谱仪(MODIS)火点探测数据、气溶胶光学厚度(AOD)数据、臭氧监测仪(OMI)的二氧化氮(NO2)柱含量密度、大气红外探空仪(AIRS)的一氧化碳(CO)柱含量密度和地面监测的PM_(2.5)、NO_2、CO浓度等数据,结合天气形势和后向轨迹分析的方法进行了系统的分析。监测数据表明:华东地区2012年6月火点数目分别在9日和13日出现高值,分别达到1714和1654个;AOD、NO_2柱含量密度、CO柱含量密度与火点的变化趋势大致相同。利用HYSPLIT前向轨迹模式和火点分布可知:到达常州的高低空气流均经过火点源区时,地面和大气柱污染物浓度发生显著的协同变化;而当到达常州的高低空气流传输轨迹不同时,地面和大气柱污染物浓度变化趋势不一致。本次常州地区污染事件主要是由山西、河北、河南、山东、安徽、江苏北部的秸秆燃烧排放的大气污染物经大气高空传输扩散所致。     

一次雷暴前后大气折射率的多普勒天气雷达测量试验及结果

由温度、气压和水汽压决定的大气折射率会影响天气雷达电磁波的传播路径和目标回波的相位。因此,通过测量目标回波相位的变化能够算出大气折射率的变化,进而得到水汽信息,为研究局地对流天气和水汽平流提供资料。本文阐述了多普勒天气雷达反演大气折射率的原理和方法,并利用江苏省气象台的S波段多普勒天气雷达反演了一次雷暴过程前后的大气折射率,表明了雷达探测大气折射率的可靠性。这项工作有望为研究水汽变化和天气过程提供高分辨率的遥感资料,也可以为数值模式提供水汽场辅助数据,有良好的应用前景。     

不同扰动场对大气重力波参数结果影响的初步探讨

如何获取大气重力波参数是大气动力学理论研究的重点和难点。本文以2013年8月6—8日晋西北地区出现的一次雷阵雨天气过程为例,利用常用的二阶、三阶、四阶曲线拟合和带通滤波方法获取垂直高分辨率探空资料的扰动场,对这些扰动场提取的大气重力波参数进行对比分析。结果表明:不同扰动场(二阶、三阶、四阶曲线拟合以及带通滤波)对所获取重力波参数的大小及变化趋势存在影响,但对不同重力波参数的影响程度不一样。其中,对波固有周期、水平和垂直波长的大小及变化趋势影响很大,而对波传播方向、对地水平群速及固有相速的影响程度则较弱。结合6—8日天气现象的大气动力特征,发现由二阶曲线拟合、带通滤波对应扰动场得到的重力波参数的大小及变化趋势与此吻合,其结果可信度最高;而由四阶曲线拟合扰动场得到重力波参数值的可信度最低。     

Trends in impact of acidification on groundwater bodies in the Czech Republic; an estimation of atmospheric deposition at the horizon 2015

The acidification of surface and groundwaters is a long standing issue in the Czech Republic which culminated in the second half of the last century by mass extinction of forest cover in many mountainous regions. The total deposition of sulfur at that time was reaching as much as about 108 kg/ha/year. This resulted in a decrease of alkalinity in groundwaters, decrease of pH and on the other hand an increase in concentration of nitrates, sulfates, berylium and aluminium. Desulfurization of power plants and attenuation of heavy industry leads to a decrease in sulfur deposition down to the present mean values around 16.5 kg/ha/year. It is expected that around the year 2010 the sulfur deposition should not have a substantial impact on the environment providing the similar trend would continue. However, a reverse trend can be observed in deposition of nitrogen. The growth of road traffic and more frequent use of earth gas for heating lead to a dramatic rise in nitrogen throughfall of which mean value increased from 15.4 kg/ha/year in 1990 up to 25.7 kg/ha/year in 2001. If such trend continues in future, then the mean values of nitrogen throughfall would attain 37.8 kg/ha/year in 2015, so that the nitrogen would take over the role of sulfur in acidification. Therefore, the problem of acidification in Central Europe is by no means resolved, only the structure of acidification input has been changed.     

A New Temperature Channel Selection Method Based on Singular Spectrum Analysis for Retrieving Atmospheric Temperature Profiles from FY-4A/GIIRS

Hyperspectral data have important research and application value in the fields of meteorology and remote sensing.With the goal of improving retrievals of atmospheric temperature profiles, this paper outlines a novel temperature channel selection method based on singular spectrum analysis(SSA) for the Geostationary Interferometric Infrared Sounder(GIIRS), which is the first infrared sounder operating in geostationary orbit. The method possesses not only the simplicity and rapidity of the principa...     

基于偏差原则利用MODIS红外资料反演大气廓线以及表层温度

遥感方程或大气辐射传输方程是属于第一类非线性Fredholm积分方程,这类方程的显著特征是不适定的,尤其此类问题解的不稳定性,增加了反演的难度.因此需要研究控制反演不稳定性和提高反演精度的有效方法.为了使解稳定,光滑参数γ作为约束因子是必要的.文中结合牛顿非线性迭代法反演大气廓线,利用偏差原则来最优选择光滑参数γ,即在同步反演大气廓线的同时对γ采用分步迭代的原则.最后利用中分辨率和成像光谱仪(MODIS)红外资料进行反演试验,反演结果表明采用偏差原则选取γ明显优于经验法,反演的表层温度和大气可降水量与美国国家宇航局(NASA)的MOD07产品类似.     

苏州市大气PM_(2.5)中水溶性无机离子的源解析及其气象因子分析

为了探明PM_(2.5)中水溶性无机离子的来源和气象因子对其浓度变化的影响,利用2012年2、5、8和11月苏州市PM_(2.5)中水溶性无机离子浓度和本站气象观测数据,分析了苏州市水溶性无机离子的时间变化特征,解析了当地PM_(2.5)中水溶性无机离子的主要来源,探讨了气象因素对离子组分的影响。结果表明:(1)苏州市PM_(2.5)中水溶性无机离子年均浓度大小依次为:SO_4~(2-)NO_3~-NH_4~+Na~+Cl~-K~+Ca~(2+)Mg~(2+)F~-;SO_4~(2-)、NH_4~+和NO_3~-为PM_(2.5)中最重要的3种水溶性无机离子物种,其总和占PM_(2.5)总质量浓度的50.9%。各离子的季节浓度特征均为冬季最高、夏季最低。(2)通过运用主成分分析法对苏州市PM_(2.5)中水溶性无机离子进行来源分类解析,发现第一类为二次污染源和生物质燃烧,其贡献率为32.84;第二类为道路扬尘及工业排放,其贡献率为19.99%;第三类为海盐污染,其贡献率为18.43%。(3)通过水溶性无机离子与气象条件的相关性分析发现,风向、风速和温度与水溶性无机离子浓度的相关性较显著,这三者是颗粒物浓度变化的主要影响因子。(4)利用HYSPLIT后向轨迹模式对外来污染物进入苏州市的轨迹进行聚类分析后发现:因受季风气候影响,苏州市外来污染物的输入路径存在明显的季节性变化特征,其中夏半年输送主径源自海上,冬半年主径源自内陆。