微波遥感在大气边界层预报中的应用

本文利用5mm(54.5 GHz)微波辐射计遥感大气边界层的温度廓线,并利用大气边界层数值模式,预报大气边界层的发展。首先改善5 mm微波辐射计遥感大气温度层结的方法,提高精度;其次建立模拟和预报大气边界层发展的一维数值模式,用微波辐射计观测结果每3小时对模式进行一次初始化,使模式能跟踪和预报实际大气边界层的发展,并用实测资料做了验证。     

AN ERROR ANALYSIS ON THE SIMULATED DATA OF TOVS HIRS BY RTTOV5 MODEL*

The sounding data of meteorological satellites provide not only the real time weather information about the distribution of both cloud and rainfall,but also some others about the movement and state of atmosphere.They are important variables and parameters for NWP model used to simulate and predict atmospheric state.In order to introduce remote sensing information from satellites into NWP model,there is an efficient way of establishing an RT model by use of the atmosphere radiation sounding data of meteorological satellites to get the variables and parameters valuable to NWP model.In this paper,we set up profiles of air temperature and water vapor from the surface to upper (0.1 hPa) using the radiosounding data and the surface data from May to August 1998 atmosphere East Asia.A TOVS RT model (RTTOV5) is provided to compute the value of radiation value of HIRS channels in NOAA14.Then the radiation values of 19 HIRS channels are gotten.After matching these data computed by the RT model and the corresponding values coming from satellite sounding in time,the statistic distribution of bias between tile model output and the satellite sounding at each sounding channel can be gotten.At the same time.the distribution of RMS to every TOVS HIRS channel,the standard biases to different scanning angle to each channel are also obtained.     

AN ERROR ANALYSIS ON THE SIMULATED DATA OF TOVS HIRS BY RTTOV5 MODEL

The sounding data of meteorological satellites provide not only the real time weatherinformation about the distribution of both cloud and rainfall,but also some others about themovement and state of atmosphere.They are important variables and parameters for NWP modelused to simulate and predict atmospheric state.In order to introduce remote sensing informationfrom satellites into NWP model,there is an efficient way of establishing an RT model by use of theatmosphere radiation sounding data of meteorological satellites to get the variables and parametersvaluable to NWP model.In this paper,we set up profiles of air temperature and water vapor fromthe surface to upper (0.1 hPa) using the radiosounding data and the surface data from May toAugust 1998 atmosphere East Asia.A TOVS RT model (RTTOV5) is provided to compute thevalue of radiation value of HIRS channels in NOAA14.Then the radiation values of 19 HIRSchannels are gotten.After matching these data computed by the RT model and the correspondingvalues coming from satellite sounding in time,the statistic distribution of bias between tile modeloutput and the satellite sounding at each sounding channel can be gotten.At the same time.thedistribution of RMS to every TOVS HIRS channel,the standard biases to different scanning angleto each channel are also obtained.     

利用双频微波辐射计测空中水汽和云液水含量的个例分析

利用23.8GHz和31.65GHz双频地基微波辐射计观测资料,结合卫星云图、雷达、探空和自记雨量计等资料分析了2005年4月在河南新乡观测的不同云系影响时大气垂直积分含水量(V)和云中液态含水量(L)的演变特征,对4月8日低槽云系影响时V、L的特征进行了分析。结果表明:双频辐射计对空中水汽和液态水反映灵敏,不同天气背景时对应有不同的V、L值分布。云液水含量L的变化与云量的增减有关。降水开始之前,水汽含量V值有明显波动,液态水含量L值也有明显增加,一般增大到0.4mm时即出现降水。这些现象对降水开始有指示意义,可预测云系正处于降水产生的阶段,可应用于人工增雨作业。此外,根据微波辐射计观测资料分析了大气水汽、云液水和地面降水之间的定量关系,云中液态水仅占汽态水的8.7‰左右,落回地面的降水占空中水汽量的18%左右。     

Study on clouds and marine atmospheric boundary layer

A set of remote sensing instruments of Peking University, which includes mainly a dual~channel(22.235GHz and 35.5GHz) microwave radiometer, a 8mm microwave and a 5mm microwave radiometer, has been developed for the Western North-Pacific Cloud-Radiation Experiment (WENPEX). The instruments were used to observe the cloud and marine atmospheric boundary-layer in the southwest sea area of Japan in winter time from 1989 to 1991. In the weather change process, the characteristics of the marine atmospheric boundary-layer and liquid water content in cloud of this area in winter time are studied from observation data. A one-dimensional mixed layer model is presented for the growth and evolution of a cloud-topped marine boundary-layer. The model is used to study in the WENPEX. The simulation results are in agreement with observation data, especially the integral water in cloud.     

中尺度强暴雨云团云特征的多种卫星资料综合分析

针对2002年6月23—27日发生于江淮地区的一次中尺度强暴雨过程，利用FY-1D，EOS和NOAA卫星的可见光、红外、微波通道遥感观测、反演资料，从相态、光学厚度、垂直结构等各方面分析云特征，并将分析结果与同时段地面雨量观测进行对比分析，发现云光学厚度大且云顶粒子为大粒子、冰相态是此次降雨过程中云团的主要云特征，地面雨量的大小与云光学厚度密切相关，两者间基本呈正相关关系；稳定少变的大光学厚度云或云光学厚度显著增大均可带来强的地面降水。微波资料可以很好地体现降雨云团的垂直结构。分析结果显示，卫星遥感对揭示中尺度强暴雨云团的云特征，具有很好的指示作用。     

Estimation of Indian summer monsoon rainfall using Kalpana-1 VHRR data and its validation using rain gauge and GPCP data

In the present study, an attempt has been made to estimate and validate the daily and monthly rainfall during the Indian summer monsoon seasons of 2008 and 2009 using INSAT (Indian National Satellite System) Multispectral Rainfall Algorithm (IMSRA) technique utilizing Kalpana-1 very high resolution radiometer (VHRR) measurements. In contrary to infrared (IR), microwave (MW) rain rates are based on measurements that sense precipitation in clouds and do not rely merely on cloud top temperature. Geostationary satellites provide broad coverage and frequent refresh measurements but microwave measurements are accurate but sparse. IMSRA technique is the combination of the infrared and microwave measurements which make use of the best features of both IR- and MW-based rainfall estimates. The development of this algorithm included two major steps: (a) classification of rain-bearing clouds using proper cloud classification scheme utilizing Kalpana-1 IR and water vapor (WV) brightness temperatures (Tb) and (b) collocation of Kalpana-1 IR brightness temperature with Tropical Rainfall Measuring Mission (TRMM)-Precipitation Radar (PR) surface rain rate and establishment of a regression relation between them. In this paper, the capability of IMSRA as an operational algorithm has been tested for the two monsoon seasons 2008 and 2009. For this, IMSRA has been used to estimate daily and monthly rainfall and has been intercompared on daily and monthly scales with TRMM Multisatellite Precipitation Analysis (TMPA)-3B42 V6 product and Global Precipitation Climatology Project (GPCP) rain product during these two monsoon years. The daily and monthly IMSRA rainfall has also been validated against ground-based observations from Automatic Weather Station (AWS) Rain Gauge and Buoy data. The algorithm proved to be in good correlation with AWS data over land up to 0.70 for daily rain estimates except orographic regions like North-East and South-West India and 0.72 for monthly rain estimates. The validation with Buoys gives the reasonable correlation of 0.49 for daily rain estimates and 0.66 for monthly rain estimates over Tropical Indian Ocean.     

地基微波辐射计探测大气边界层高度方法

采用2013年中国科学院大气物理研究所香河大气综合观测试验站的地基微波辐射计和激光雷达观测数据,以激光雷达探测的大气边界层高度为参考,分别利用非线性神经网络和多元线性回归方法建立微波亮温直接反演大气边界层高度的算法,并对比两种方法的反演能力, 同时分析非线性神经网络算法在不同时段及不同天气状况下反演结果的差异。结果表明:非线性神经网络算法的反演能力优于多元线性回归算法,其反演结果与激光雷达探测的大气边界层高度有较好一致性,冬、春季的相关系数达到0.83,反演精度比线性回归算法约高26%;对于不同时段和不同天气条件,春季的反演结果最好,晴空的反演结果好于云天; 四季和不同天气状况的划分也有利于提高反演精度。     

邢台地区微波辐射计与无线电探空仪数据对比分析

利用2018年1月至2019年12月河北省中南部地区的微波辐射计和探空数据，将两种探测设备取得的资料在时间和空间上进行点对点匹配，共筛选出187条晴空廓线、1176条云天廓线和12条毛毛雨天廓线，定量分析了各个高度层的晴天、云天和毛毛雨天气条件下两种大气探测设备的温度、相对湿度和水汽密度廓线的相关性及误差情况。结果表明：3种天气条件下的微波辐射计与无线电探空仪温度和水汽密度的相关性整体较好，地基微波辐射计观测的大气参数分布存在不同程度的差异，但是微波辐射计和探空的变化趋势一致性较好，并且无线电探空仪观测的大气参数和微波辐射计反演的温度、相对湿度和水汽密度相关性整体上均呈现低层大气优于高层大气，温度相关性最好，水汽密度次之，相对湿度最低。通过对比各个高度层的拟合程度，发现3.5 km以下的低层大气参数精度更可靠，对于需要间接计算的大气物理量，如K指数、有效位能、积分水汽含量等，使用低层数据计算的大气物理量精度会更好。本文开展的地基微波辐射计反演的大气物理参数与探空仪观测对比研究工作，对提高微波辐射计在大气物理和人工影响天气的探测精度方面具有参考意义。     

三波段地基微波辐射计联合遥感云雨大气参数的方法

本文提出了一种用三波段（0.86，1.35，3.2 cm）地基微波辐射计联合反演雨天大气的水汽总量Q，云路径积分液水含量L和雨的垂直路径参数的物理迭代方法。134份样本数值检验结果表明:当雨强小于20 mm／h时，反演的Q，L及雨参数值与模拟真值的相对误差分别在4％，18％，13％以内；当雨强超过20 mm／h时，相对误差分别是25％，57％和3％。文中还特别指出，单独用3.2 cm辐射计测小雨雨强时，相对误差很大，而联合反演能大大提高测雨精度。最后，讨论了该方法的实际应用可能性，表明三波段联合，为全天候监测大气中的水，提供了实际可行的途径。     

被动式微波遥感技术发展及其对汽/液态水物理参数反演的研究进展

大气遥感是1960年代以来发展最为迅速的学科分支之一,也是大气科学发展的关键技术支柱之一;其中,被动式微波遥感具有体积及功耗小,能进行全天候连续观测等优点,为获取大气、海洋、陆面等多领域观测信号提供了直接和有利手段。由于水汽、液态水是影响天气气候变化的重要要素,对其的探测技术在当前气象业务中显得尤为重要。简单回顾了被动式微波遥感的主要进展,重点介绍微波辐射计对水汽、云液态水、降水等物理量进行反演时所采用的统计方法、物理方法、物理统计方法等方法研究方面的国内外进展,并对微波辐射计的未来发展前景作了简单介绍。     

The investigation of microwave precipitation measurement at 37GHz

In this paper we use a 10-layer radiation transfer model to systematically investigate the relation between brightness temperature and the rainfall rates at 37 GHz, including various viewing of microwave (MW) remote sens-ing and different surface condition, with main focus on the influence of the structure of ice-phase layer. The results show that the quantitative rainfall measurement can not be reliably obtained over the land from spaceborne radiometer at this wavelength and the structures of ice layer are very important in determining the “observed” bright-ness temperature for the spaceborne MW remote sensing.     

不同天气条件下地基微波辐射计探测性能比对

利用探空数据和毫米波云雷达数据,对在大气探测试验基地同址观测的国内外3种型号地基微波辐射计进行1年（2016年10月—2017年9月）的比对分析,重点分析不同型号地基微波辐射计在晴空和云天下温、湿观测性能特征。结果表明:3种型号地基微波辐射计温度与探空相关系数均超过0.98,达到0.01显著性水平;晴空条件下,德国及国产地基微波辐射计温度平均误差均在±1℃以内（前者为负偏差,后者为正偏差）,误差较小,美国地基微波辐射计系统偏差约为-1.8℃;3种型号地基微波辐射计均方根误差随高度递增,整体均方根误差以德国地基微波辐射计2.2℃为最小,美国地基微波辐射计3.8℃为最大;在有云条件下,3种型号地基微波辐射计平均误差分布较晴空条件下无明显变化,均方根误差较晴空条件有约增加0.5℃。3种型号地基微波辐射计均呈晴空相对湿度误差小于云天误差,低空误差小于中高空误差的特点;晴空条件下,美国与国产地基微波辐射计相对湿度均方根误差分别为15%和18%左右,小于德国地基微波辐射计;云天条件下3种型号微波辐射计均方根误差均较大（26%左右）。     

Ground-based remote sensing of LWC in cloud and rainfall by a combined dual-wavelength radar-radiometer system

This paper describes the retrieval procedure of liquid water content (LWC) in cloud or rainfall distri-bution by a combination of microwave radiometry and radar and its numerical simulation. The per-formance of a combined dual-wavelength (35.0& 9.375 GHz) radar-radiometer system for the remote sensing of cloud LWC and rainfall is given. During the two summers of 1980 and 1981, the preliminary obser-vations of different clouds and storms by the combined system and combined radar-radiometric cloud and rain parameter retrievals are carried out. Research results show that by the use of the combined radar-radiometric method, improvement are obtained in accuracy of rms LWC and rainfall over the pure radio-metric technique or the radar alone.     

微波辐射计温湿廓线反演方法改进试验

为提升地基微波辐射计在不同天气条件下, 特别是云天条件下温湿廓线的反演精度, 利用2011年1月—2016年12月中国气象局北京国家综合气象观测试验基地探空数据, 在微波辐射计反演温湿度廓线的过程中通过区分晴天和云天条件并引入全固态Ka波段测云仪云高及云厚信息, 对反演输入亮温进行质量控制和偏差订正, 建立BP神经网络模型, 采用2017年1月—2018年3月微波辐射计探测数据评估检验, 结果表明:在亮温订正前提下, 晴天温度模型、云天温度模型、晴天相对湿度模型和云天相对湿度模型反演结果与探空的相关系数分别为0.99, 0.99, 0.80和0.78, 均方根误差为2.3℃, 2.3℃, 9%和16%, 较微波辐射计自带产品（LV2产品）减小约0.4℃, 0.3℃, 11%和9%, 准确性提升约30%, 28%, 64%和45%;温度模型偏差在±2℃以内、湿度模型偏差在±20%以内的占比分别为68%, 70%和95%, 78%, 较LV2产品分别提高了7%, 5%和27%, 23%, 其中相对湿度改善明显。可见亮温订正、区分天气类型训练反演模型有利于改善地基微波辐射温湿廓线反演精度。     

沙尘气溶胶卫星遥感现状与需要关注的若干问题

沙尘暴是全球干旱、半干旱地区特有的一种灾害性天气,所产生的沙尘气溶胶是全球气溶胶系统重要组成部分,对全球环境、天气、气候和生态有复杂的影响。沙尘气溶胶作为一种吸收性气溶胶,对太阳辐射有着较强的吸收,还能通过加热大气、改变大气稳定度、蒸发云滴、减少云量等"半直接方式"影响气候。卫星遥感对沙尘气溶胶的监测具有独特的优势,是全球沙尘研究的重要手段。本文系统整理和介绍了目前常用的可见近红外、热红外、被动微波、紫外和主动激光测量等五类卫星遥感沙尘气溶胶的主要方法,在总结典型遥感仪器和主要产品基础上,讨论了遥感产品的定量精度和地面验证问题,结合辐射传输理论模拟了可见近红外和热红外的卫星观测,探讨了可见近红外遥感的地表反照率影响和热红外高光谱遥感的波段选择问题,最后对未来的一些研究重点进行了展望。     

基于气象资料变化特征和辐射传输模式的微波辐射计工作状态分析

提出利用晴天每天早晨08时的观测资料,以大气温度季节变化统计特征为依据,来判断微波辐射计观测期间的工作状态。简要介绍了大气微波辐射传输方程,以南京冬春季节大气温度变化的统计特征为依据,以2010年11月27日—2011年5月29日期间南京某辐射计08时晴天的实验观测资料为例,通过对其12个通道的亮温观测值和计算值进行统计对比和物理分析,给出该辐射计实验观测期间的工作状态判断,认为用于湿度遥感的22.235、23.035、23.835、26.235和30.000GHz五个通道观测期间工作状态良好、稳定,而用于温度遥感的51.25、52.28、53.85、54.94、56.66、57.29和58.80 GHz七个通道性能一直衰退。本文提出的方法可供微波辐射计工作状态监测和观测资料质量控制参考。     

大气遥感研究展望

对大气遥感研究发展方向作了展望,重点论述了如下几个方面:1)未来大气遥感研究若干特点;2)主被动式相结合的卫星大气遥感;3)大气遥感技术与应用集成;4)大气和地表物理参数的综合遥感;5)气溶胶与云光学特性遥感;6)微量气体时空分布遥感;7)地基大气遥感及走向综合集成.     

地基遥感大气水汽总量和云液态水总量的研究

介绍了地基微波辐射计遥感反演大气柱中的水汽总量和云液态水总量的辐射传输原理和反演方法。给出了实用的有气候代表性的北京地区4个季节的反演公式，并对反演公式进行了数值检验，分析了反演精度：春、夏、秋、冬4季水汽总量反演的相对标准偏差分别为3．1％、1．6％、2．2％和2．4％。用反演公式反演在香河探测的NASA微波辐射计资料发现：微波辐射计反演的水汽总量平均比探空测量值偏大O．21cm，二者的线性相关系数为0．988．均方根误差为0．16cm：云液态水总量除降水云天外．值均在0．1mm以下。     

国产MWP967KV型地基微波辐射计探测精度

MWP967KV型地基微波辐射计是我国自主研发,拥有完整自主知识产权的新型大气微波遥感探测设备,为了实现国产设备在气象业务中的应用,需对设备的探测精度进行对比分析。利用2015年8月—2018年3月四川盆地南部山区的无线电探空数据和地基微波辐射计数据,分析晴空和有云天气条件下温度廓线、相对湿度廓线和水汽密度廓线及相关物理参数的精度。结果表明:晴空、层积云和高积云的微波辐射计与探空仪的温度、水汽密度和相对湿度相关系数整体上分别在0.9890,0.9665,0.5868以上,均达到0.01显著性水平。3种参数廓线的相关系数整体均呈地面大于高空,仅温度廓线相关系数达到0.01显著性水平,相对湿度廓线和水汽密度廓线在高空的相关系数未达到0.01显著性水平。3种参数的相关性整体上温度最高,水汽密度次之,相对湿度最低。温度、相对湿度和水汽密度的均方根误差平均值分别为2.8℃,22%和1.38 g·m-3,温度廓线和相对湿度廓线在层积云和高积云的云中及云上的精度明显降低,均方根误差较云层下温度升高1℃~2℃,相对湿度增大10%~20%。逆温层会影响廓线及物理参数的精度。晴天或云天等大范围相似天气条件下,探空气球飘移距离与温度廓线、相对湿度廓线和水汽密度廓线偏差的相关性较弱。