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Downscaling atmospheric patterns to multi-site precipitation amounts in southern Scandinavia

机译：将斯堪的那维亚南部的大气模式缩减至多点降水量

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摘要

A non-homogeneous hidden Markov model (NHMM) is applied for downscaling atmospheric synoptic patterns to winter multi-site daily precipitation amounts. The implemented NHMM assumes precipitation to be conditional on a hidden weather state that follows a Markov chain, whose transition probabilities depend on current atmospheric information. The gridded atmospheric fields are summarized through the singular value decomposition (SVD) technique. SVD is applied to geopotential height and relative humidity at several pressure levels, to identify their principal spatial patterns co-varying with precipitation, we assume the common hidden weather state process to completely account for the temporal structure of precipitation. Given the current weather state, the multivariate probability distribution of precipitation occurrences is approximated using a Chow-Liu tree dependence structure, involving products of bivariate distributions. Conditional on the weather state, precipitation amounts are modelled separately at each gauge as independent gamma-distributed random variables. This modelling approach is applied to 51 precipitation gauges in Denmark and southern Sweden for the period 1981-2003. The downscaling model produces robust predictions of data statistics, such as expected precipitation amounts and spell duration distributions. Moreover, the model-defined weather states show a satisfactory degree of physical consistency.
机译：应用非均匀隐马尔可夫模型（NHMM）将大气天气模式缩减为冬季多站点日降水量。已实施的NHMM假设降水以遵循马尔可夫链的隐藏天气状态为条件，该状态的过渡概率取决于当前的大气信息。通过奇异值分解（SVD）技术总结了栅格化的大气场。 SVD应用于几种压力水平下的地势高度和相对湿度，以识别其与降水变化的主要空间格局，我们假设使用共同的隐藏天气状态过程来完全考虑降水的时间结构。给定当前的天气状况，使用Chow-Liu树相关性结构（包括二元分布的乘积）来估算降水发生的多元概率分布。根据天气状况，在每个仪表上分别将降水量建模为独立的伽玛分布随机变量。该建模方法适用于1981-2003年期间在丹麦和瑞典南部的51个降水量仪。缩减模型可对数据统计信息进行可靠的预测，例如预期的降水量和符咒持续时间分布。此外，模型定义的天气状态显示出令人满意的物理一致性。

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  • 来源
    《Hydrology research》 |2010年第4期|P.193-210|共18页
  • 作者

    Emiliano Gelati; Ole Bossing Christensen; Peter F. Rasmussen; Dan Rosbjerg;

  • 作者单位

    Department of Environmental Engineering,Technical University of Denmark,Miljovej, Building 113,DK-2800 Kongens Lyngby,Denmark;

    rnDanish Meteorological Institute,Lyngbyvej 100,DK-2100 Copenhagen,Denmark;

    rnDepartment of Civil Engineering,University of Manitoba,Winnipeg, MB R3T 5V6,Canada;

    rnDepartment of Environmental Engineering,Technical University of Denmark,Miljovej, Building 113,DK-2800 Kongens Lyngby,Denmark;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    chow-liu trees; downscaling; hidden markov model; precipitation model; southern scandinavia;

    机译：li柳树;缩小规模;隐藏的马尔可夫模型;降水模型斯堪的纳维亚南部;

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