| 极轨卫星高层通道在GRAPES同化系统中的应用 |
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| 引用本文： | 钟亦鸣,李刚,张华.极轨卫星高层通道在GRAPES同化系统中的应用[J].大气科学学报,2016,39(2):280-288. |
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| 作者姓名： | 钟亦鸣 李刚 张华 |
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| 作者单位： | 南京信息工程大学, 江苏 南京 210044;南京信息工程大学, 江苏 南京 210044;中国气象局数值预报中心, 北京 100081 |
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| 基金项目： | 公益性行业(气象)科研专项(GYHY200806003) |
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| 摘 要： | 针对GRAPES(Global/Regional Assimilation and Prediction System)模式三维变分系统高层背景场温湿廓线外推方案的局限性,提出以气候垂直廓线重新构造高层温湿垂直结构,以减小外推方案的偏差。首先采用一维变分同化系统,展开模拟实验:分析目前模式中使用的外推方案误差及其对反演结果的影响,利用高层大气气候廓线构造垂直结构并分析同化偏差。最后,运用GRAPES全球分析预报系统进行同化实验并分析改进程度。结果显示:模拟研究表明采用高层背景场温湿廓线外推方案与实际观测相比最大偏差在1 h Pa附近可达数十度以上,不仅影响平流层,而且对对流层也有影响;用气候温度数据修正GRAPES高层温度数据,可以减少50%以上的偏差,证明了用气候值高层数据优化现行GRAPES模式中同化系统高层插值方案的可行性。全球GRAPES三维变分同化试验结果显示,改进方案不仅显著的改善平流层分析质量,对对流层中高层也有改进。
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| 关 键 词： | 数值预报 资料同化 三维变分 |
| 收稿时间： | 2013/2/15 0:00:00 |
| 修稿时间： | 2013/4/16 0:00:00 |
Polar-orbiting satellites upper-atmosphere channel application for the Global/Regional Assimilation and Prediction System |
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| ZHONG Yiming,LI Gang and ZHANG Hua.Polar-orbiting satellites upper-atmosphere channel application for the Global/Regional Assimilation and Prediction System[J].大气科学学报,2016,39(2):280-288. |
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| Authors: | ZHONG Yiming LI Gang and ZHANG Hua |
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| Institution: | Nanjing University of Information Science & Technology, Nanjing 210044, China;Nanjing University of Information Science & Technology, Nanjing 210044, China;Numerical Weather Prediction Center of CMA, Beijing 100081, China |
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| Abstract: | In order to reduce the limitations and bias of the temperature and humidity profiles extrapolation scheme of the GRAPES(Global/Regional Assimilation and Prediction System) 3-DVar systems for the upper-atmosphere background,this paper proposes to use climatic data to reconstruct upper-atmosphere vertical profiles of temperature and humidity.First,a series of simulation experiments were conducted by a one-dimensional variational data assimilation system to analyze the bias of the current extrapolation program and its effects on inversion results.Then,vertical profiles were constructed using upper-atmosphere climatic data,and assimilation deviation was also discussed.Finally,assimilation experiments were performed and analyzed through the GRAPES global analysis and forecast system.The one-dimensional variational system experiments showed that there was deviation between the structure of the current upper background field of temperature and humidity profiles extrapolation scheme and the actual conditions of the upper atmosphere.Its inversion results suggested a greater negative impact of the stratosphere and troposphere.The application of climatic data to correct the upper atmospheric background field(temperature and humidity profiles) could reduce the deviation by over 50%,which further proved the feasibility of using upper climatic data to replace the upper background field produced by the temperature and humidity profiles interpolation scheme in the current GRAPES model assimilation system.The results from the GRAPES global 3DVar assimilation experiment indicated that using climatic data to replace the temperature and humidity profile structure of the upper atmosphere can significantly improve the inversion results of the stratosphere and upper troposphere.The upper atmosphere climate profile corrections for the background field can improve the analysis results of the GRAPES-3DVar system,reboot the upper atmosphere satellite channel and optimize the assimilation and forecast result of the GRAPES model.The final results showed that the maximum of the upper background temperature and humidity profiles extrapolation scheme error in the one-dimensional experiments could reach tens of degrees or more around the 1 hPa level,not only affecting the stratosphere but also having an impact on the troposphere.Using climate data to correct the GRAPES upper temperature and humidity data,the temperature deviations can be reduced by over 50%,which fully proves the feasibility of replacing the interpolation assimilation system in the current GRAPES model with the top-level climate data scheme.The global GRAPES-3DVar assimilation test results showed that the new scheme not only significantly improves the quality of the analysis of the stratosphere,but also the upper troposphere.This paper has preliminarily improved the upper atmospheric temperature and moisture profiles construction scheme for the GRAPES model.However,there is still room for optimizing the GRAPES-3DVar model upper-atmosphere assimilation.Channel selection schemes for different kinds of data and error correction techniques need to be further studied.The data used in the assimilation cycle experiment were conventional observations and microwave thermometer data(AMSU-A) from NOAA-15/16.The NCEP reanalysis data were used as testing data.The control group(CTRL) used the original upper-atmosphere background field produced by the temperature and humidity profile extrapolation scheme;the experiment group(TEST) used the climate profile correction scheme.During the experiments,the control group and the experimental group both used the same data and satellite channel selection method.The radiative transfer model was RTTOV7 in the GRAPES system. |
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| Keywords: | numerical weather forecast data assimilation three-dimensional variational model |
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