赵虹,秦正坤,王金成,刘寅. 2015. 经验正交函数分解质量控制法在地面观测资料变分同化中的个例研究与应用[J]. 气象学报, 73(4):749-765, doi:10.11676/qxxb2015.053
经验正交函数分解质量控制法在地面观测资料变分同化中的个例研究与应用
Case studies and applications of the Empirical Orthogonal Function quality control in variational data assimilation systems for surface observation data
投稿时间:2015-01-27  修订日期:2015-04-08
DOI:10.11676/qxxb2015.053
中文关键词:  经验正交函数分解质量控制  资料同化  WRF-3DVAR  降水
英文关键词:EOF-QC  Data assimilation  WRF-3DVAR  Precipitation
基金项目:公益性行业(气象)科研专项(GYHY201406008)、江苏省普通高校研究生科研创新计划项目(CXZZ13_0503)、江苏高校优势学科建设工程项目(PAPD)。
作者单位
赵虹 南京信息工程大学大气科学学院资料同化研究与应用中心, 南京, 210044
江苏省南京市六合区气象局, 南京, 211500 
秦正坤 南京信息工程大学大气科学学院资料同化研究与应用中心, 南京, 210044 
王金成 中国气象局数值预报中心, 北京, 100081 
刘寅 南京信息工程大学大气科学学院资料同化研究与应用中心, 南京, 210044
江苏省气象探测中心, 南京, 210009 
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中文摘要:
      同化地面观测资料能够获得丰富的地面大气信息,这对于大气边界层的准确模拟尤为重要。由于地面观测资料同化一直受到地面观测资料质量较差的影响,因此,地面观测资料的质量控制是提高地面资料同化效果的重要方法之一。为了分析基于经验正交函数分解质量控制方法(Empirical Orthogonal Function quality control,EOF-QC)对地面资料同化效果的影响,并进一步检验该方法在实际同化试验中的应用效果,在WRF的三维变分同化系统中引入了经验正交函数分解质量控制法,同时通过一系列同化试验比较了经验正交函数分解质量控制法与原系统自带的基于观测与模拟偏差质量控制法(Observation Minus Background quality control,OMB-QC)的差异。2008年1和7月的多个强降水预报试验结果表明,经验正交函数分解质量控制法能够保留更多天气系统的有效观测信息,更为客观准确地反映大气真实状态;同化经过经验正交函数分解质量控制法后的观测资料,模式预报的温度降低,在北部形成一个气旋性环流,该环流底部的偏西气流带动北部冷空气东移入海,同时冷空气南下也削弱了带有丰富水汽的西南气流,从而使模式预报的降水范围和强度更加合理。降水的空间分布对比结果也表明,经验正交函数质量控制法改善了模式对降水落区和强度的预报能力,各个量级的降水评分有明显提高,模拟结果更接近于实况。各组数值模拟试验结果表明,经验正交函数分解质量控制法在WRF-3DVAR中具有较高的应用潜力。
英文摘要:
      Surface data assimilation can provide a wealth of ground information, which is particularly important for the accurate simulation of atmospheric boundary layer. Surface data assimilation has always been impacted by the poor quality of observations, and an improving data quality control (QC) method for surface observations is an essential way to advance the effect of data assimilation. In order to improve the impact of surface data assimilation and discuss the influence of this method for precipitation forecast, the EOF (Empirical Orthogonal Function)-QC is introduced into the WRF three-dimensional variational assimilation system. Two severe precipitation events during the periods of 28-29 January 2008 and 14-15 July 2008 have been used to investigate the difference between the EOF-QC and the OMB (observation minus background)-QC. The results show that the EOF-QC can retain weather oscillations in the observations more effectively and reflect the true state of the atmosphere more objectively and accurately than the OMB-QC. The temperature is cooling when assimilating the data after EOF-QC, which yield to a cyclonic circulation, leading the cold air from the north to moving toward the east and weakening the southwest flow with abundant water vapor. The EOF-QC can make the model forecasts of the range and intensity of precipitation become more reasonable. The spatial distribution of precipitation also shows that EOF-QC can improve the forecasting capability of precipitation area and precipitation intensity, the forecasting skill scores are also significantly enhanced. The spatial distribution of precipitation is more close to the real situation than other experiments. The numerical simulations indicate that the EOF-QC method has good potential application in WRF-3DVAR.
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