变分分析技术的一次成功应用：TOVS资料的订正及效果分析

变分分折技术是近年来发展起来的最新四维同化技术,实验表明,这种方法为同化处理大量时空分布不规则、性质和精度不相同的观测资料提供了一个概念简单、内部协调的方法,本文正是在这方面作了一次大胆尝试,用变分分析方法对存在明显误差的TOVS资料进行订正,取得了满意的结果。     

应用TOVS资料变分分析技术增加青藏高原地区摸式初始场信息

首次在测站稀少的高原地区引入经变分技术处理的 TOVS卫星资料 ,通过动力诊断探讨了解决高原地区测站少、数值预报模式初始场信息误差大的技术关键问题 ,提出了采用TOVS反演资料在高原地区增加模式初始场信息的构思 ,并应用变分法处理 TOVS反演资料 ,显著地提高了高原初始场信息的可靠性 ;并从动力诊断分析角度 ,进一步证实了 TOVS反演资料的应用有利于提高高原动力系统特征的描述能力 ,并显著改善水汽输送通道分布及其层结稳定度等有关初始场信息的客观性     

TOVS资料真实性检验和偏差订正方案的设计

具有空间高分辨率的卫星垂直探测（ＴＯＶＳ）资料应用于业务时,应对反演资料的偏差分布进行检验、统计、分析,以利于选取误差稳定且较小的区域（或指标点）作为寻求和归纳预报条件时可应用于业务的反演资料;同时,进一步研究和设计了误差订正方案,经比较分析,单点指标站经回归订正后误差能得到满意的改善,而经采用变分分析后的格点场质量能得到显著提高     

TOVS资料的变分处理方法在青藏高原地区的数值试验

首次在测站稀少的高原地区引入经变分技术处理的TOVS资料,使用MM5数值模式对高原地区降水数值预报难点进行了研究。探讨了解决高原地区测站少、数值预报模式初始场信息误差大的技术关键问题,提出了采用TOVS资料在高原地区增加初始场信息的构思。数值试验结果表明,应用变分法处理后的TOVS资料,可显著地提高高原初始场信息的可靠性。考虑夏季高原地区是对流多发区特点,本文采用非静力MM5模式,并在模式初始场中增加了TOVS资料,弥补了测站稀少的高原地区使用非静力模式的不足之处。研究结果表明,本文采用的TOVS资料技术方案可能是高原区域数值模式降水预报的有效途径,并为开拓卫星资料的应用领域提供了技术思路与理论分析依据。     

TOVS资料的图形输出及误差分析

对离散的TOVS资料的位势高度和温度进行客观分析并将其图形输出，与相应时次、相应格点上的常规探测资料的客观分析场相比较，计算其平均误差，并对产生误差的原因作了一些分析。     

卫星云图资料反演的质量控制及变分同化数值试验

该文针对数值化的GMS红外卫星云图资料的特点,利用改进的统计反演方法分别求出温度和湿度估计场,设计了几种订正方案对反演出的温度和湿度进行质量控制;控制后的反演场再与常规观测资料进行变分同化,最后用MM4模式进行了模拟对比试验.结果显示,在合理的泛函设计的基础上,质量控制的好坏直接影响预报结果.用分析场格点值进行订正效果优于用测站值直接订正,加上对云图反演的值进行系统误差订正后,有效提高了降水预报准确率.值得指出的是,加进云图资料后,明显改善了模式降水预报的强度和区域,与仅用常规探空资料相比更接近于实况.     

有限区域卫星云图资料变分分析的试验研究

资料分析在数值预报中的重要性受到越来越多的关注，星目前常规探测网的时空局限性，利用分辨率较高的非常规资料势在必行。该文利用一个有限区域中尺度模式ＭＭ４，采用变分分析技术对有限区域的常规探空资料和非常规云图资料进行变分分析和数值模拟。     

卫星资料变分分析"98·7"武汉-黄石地区特大暴雨中尺度锋面对流特征

采用卫星TOVS反演资料变分-滤波处理技术对1998年7月20～23日武汉-黄石特大暴雨成因进行了诊断分析,研究结果揭示了武汉-黄石特大暴雨过程呈类似中尺度对流复合体(Mesoscale Convective Complex,简称MCC)的中尺度锋面对流系统特征,提出了"98@7"特大暴雨过程存在显著的对流系统的复合偶极子特征,中尺度急流核的垂直复合体结构,中尺度锋面"湿舌"异常特征以及大尺度梅雨系统中的中尺度锋面的"冷楔"以及高层"暖盖"结构,上述综合特征描述了"98@7"特大暴雨过程类似MCC系统的三维中尺度锋面结构物理图像.采用卫星资料变分-滤波处理方案提出大尺度梅雨系统中突发性特大暴雨的中尺度物理模型,其诊断分析及研究结论对"98@7"异常特大暴雨的成因及其形成机理提供了新的研究思路.     

变分分析技术在城市气象资料分析中的应用

随着城市气象研究和城市气象服务的深入开展,越工需要分辨率更高、精度更高的观测资料,同时,随着城市气象观测网的不断完善,已能提供较多的常规和非常规观测资料。为了得到更完善的气象要素分布场,首先应对这些常规和非常规观测资料进行客观分析。使用上海市的气象哨、常规气象观测站的观测资料和非常规观测资料进行客观分析。使用上海市的气象哨、常规气象观测站的观测资料和上海市的地表分类信息,对变分分析技术进行了实验。     

卫星云图反演资料质量控制方案在暴雨模拟中的对比研究

本文以2003年7月9～10日发生在江淮流域的暴雨过程为例,应用FY-2B卫星红外云图灰度资料,利用统计回归的反演方法求出高分辨率的温度和湿度的反演场用于改进预报的初始场。设计和对比了几种质量控制方案,再将控制后的反演场与常规资料进行同化,最后用MM5模式进行了模拟对比试验。结果表明：在模式的初始场中引入卫星云图反演场能反映出更为细致的中尺度结构,有效地增强了对降水有重要影响的高湿区;锋生函数质量控制方案改善模式的初始场,从而改善了MM5模式降水预报的落区和强度,提高了降水预报准确性及Ts评分。     

APPLICATION OF THE VARIATIONAL METHOD OF TOVS DATA OVER THE TIBETAN PLATEAU IN IMPROVEMENT OF THE INITIAL FIELD OF NUMERICAL MODELS

In this paper,TOVS satellite data are used through variational method on the data-sparseplateau area.Diagnoses are carried out to find a way to solve the large error problem of modelinitial field.It is put forward that TOVS retrieval data can be used to improve the initial field ofnumerical prediction model on Tibetan Plateau area.Through variational method,TOVS data areprocessed and the liability of the initial information on the plateau is improved.Diagnostic resultsconfirm further that the application of TOVS retrieval data can improve our capability to describethe dynamic system features on the plateau and the objectivity of related initial information such asthe distribution of water vapor channel and stratification stability.     

APPLICATION OF THE VARIATIONAL METHOD OF TOVS DATA OVER THE TIBETAN PLATEAU IN IMPROVEMENT OF THE INITIAL FIELD OF NUMERICAL MODELS*

In this paper,TOVS satellite data are used through variational method on the data-sparse plateau area.Diagnoses are carried out to find a way to solve the large error problem of model initial field.It is put forward that TOVS retrieval data can be used to improve the initial field of numerical prediction model on Tibetan Plateau area.Through variational method,TOVS data are processed and the liability of the initial information on the plateau is improved.Diagnostic results confirm further that the application of TOVS retrieval data can improve our capability to describe the dynamic system features on the plateau and the objectivity of related initial information such as the distribution of water vapor channel and stratification stability.     

RETRIEVAL OF QINGHAI-XIZANG SASWR WITH ERBE AND ISCCP DATA

In the context of 1985—1988 ERBE and 1984—1988 ISCCP planetary scale albedoes and totalcloudiness in combination with Qinghai-Xizang actinometric measurements,investigation wasperformed of the climatic retrieval of surface absorbed shortwave radiation(SASWR)in theresearch highland.Evidence suggests that the method has given higher fitting accuracy with meanerror of 9.8 W m~(-2),whereupon was calculated the monthly mean SASWR flux density at thegridpoints of 2.5°×2.5°resolution over 25—40°N,75—95°E and 63 stations alongside a set of thedistribution maps prepared for its basic features.     

利用ERBE和ISCCP资料反演青藏高原地表短波吸收辐射场

利用ＥＲＢＥ和ＩＳＣＣＰ卫星辐射及总云量资料,结合青藏高原地面日射资料,讨论了并提出了该地区地表短波吸收气候反演方法,该法的似合精度较高,平均误差为９．８Ｗ．ｍ＾－２据此计算出７５°Ｅ－９５°豚２５°Ｅ－４０°Ｎ间２．５°＊２．５°经纬网格点和高原６３个站点的各月平均地面吸收辐射通量密度,给制出其在高原的分布图,揭示其基本特征。     

单多普勒雷达径向风场反演散度场的一种新方法

为利用多普勒雷达的径向风速获得实际风场的信息,提出了一种由单多普勒雷达径向风场反演水平散度场的新方法。在二维平面内,以某个探测点为中心,建立一个分析面,在假设风场呈线性变化的前提下,直接由径向风速推导出此探测点的散度值。并对几种典型理想风场的散度场进行了反演试验,试验结果表明,反演的散度场与分析的散度场比较一致。并对反演场与分析场之间的差别进行了讨论。     

THE STUDY OF RETRIEVAL THEORY AND METHODS FROM SATELLITE REMOTE SENSING FOR METEOROLOGICAL PARAMETERS OVER EASTERN ASIA-PARTI:ISPRM AND SRRM

A review of ten-year's practice in developing the improved simultaneous physical retrievalmethod(ISPRM)is given in the hope that some creative ideas can be drawn from it.Theimprovement upon the SPRM is associated with the under-determinedness of this ill-posed inverseproblem.In our experiment,the precondition is observed that prior information must beindependent of the satellite measurements.The well-posed retrieval theory has told us that theforward process is fundamental for the retrieval,and it is the bridge between the input of satelliteradiance and the output of retrievals.In order to obtain a better result from the forward process.the full advantage of every prior information available must be taken.It is necessary to turn the ill-posed inverse problem into the well-posed one.Then by using the Ridge regression or Bayesalgorithm to find the optimal combination among the first guess,the theoretical analogueinformation and the satellite observations,the impact of the under-determinedness of this inverseproblem on the numerical solution is minimized.     

东亚地区气象参数卫星遥感反演理论和方法研究I:ISPRM和SRRM

文中对10a来改进的同步物理反演方法（ISPRM）实践与发展进行了总结。在不违背先验信息和卫星测值之间独立的原则下,所做的改进都是针对这类非适定反演问题的欠定性（under－determinedness）进行的。由适定反演理论知道,正演是反演的基础,又是卫星辐射率测值输入和反演结果输出之间的桥梁。为了获得好的正演,就必须竭尽可能充分利用一切可以使用的先验信息,把非适定反演问题转化成适定的反演问题,从而通过Ridge回归或Bayes反演过程,把先验信息、理论模拟信息和卫星探测信息三者最佳地结合起来,以最大限度减少这类反演问题的欠定性对数值解的影响。     

THE STUDY OF RETRIEVAL THEORY AND METHODS FROM SATELLITE REMOTE SENSING FOR METEOROLOGICAL PARAMETERS OVER EASTERN ASIA-PARTI:ISPRM AND SRRM*

A review of ten-year's practice in developing the improved simultaneous physical retrieval method(ISPRM)is given in the hope that some creative ideas can be drawn from it.The improvement upon the SPRM is associated with the under-determinedness of this ill-posed inverse problem.In our experiment,the precondition is observed that prior information must be independent of the satellite measurements.The well-posed retrieval theory has told us that the forward process is fundamental for the retrieval,and it is the bridge between the input of satellite radiance and the output of retrievals.In order to obtain a better result from the forward process.the full advantage of every prior information available must be taken.It is necessary to turn the ill-posed inverse problem into the well-posed one.Then by using the Ridge regression or Bayes algorithm to find the optimal combination among the first guess,the theoretical analogue information and the satellite observations,the impact of the under-determinedness of this inverse problem on the numerical solution is minimized.     

THE EFFECTS OF BOGUS TYPHOON AND OBSERVED OCEANIC DATA ON THE ABILITY OF T_(213)L_(31) TO PREDICT TC TRACK

The abilities of typhoon (TC) track prediction by a medium-range forecast model T213L31 at National Meteorological Center are analyzed and its ability to improve its TC forecasts is discussed. The results show that about 57% of the TCs could be predicted by T213L31 but the initial position errors are large.The 43% area without the prediction of TC tracks is concentrated between 13°N and 20°N and east of 120°E and lack of conventional observation data is the main reason for the absence of TC prediction in this area.The adding of bogus TC could improve the ability of TC track prediction when there is no TC vortex in the analysis field, but could only have positive effects on the short-range TC track prediction when there is TC vortex in the T213L31 analysis field.