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The heights of automatic weather station (AWS) sensors over the Antarctic ice sheet are nominal and change with snow accumulation or ablation. Therefore, the measured data may not be used directly. In this study, we analyzed the impact of snow accumulation on AWS observations using continuous measurements from three AWS that were deployed on the traverse route from the Zhongshan Station to Dome A over East Antarctica. We then corrected the measured air temperature to account for changes in the sensor height relative to the snow surface to improve the authenticity and representativeness of the observation data from the AWS. The results show that (i) the annual mean snow accumulations at Dome A, Eagle and LGB69 were approximately 0.11 m, 0.30 m and 0.49 m, respectively, and the corresponding annual mean air temperature differences between the corrected and measured values at 1 m in height were 0.34℃, 0.29℃ and 0.35℃; (ii) the impact on air temperature from accumulation decreases with height from the surface; (iii) the air temperature difference between the corrected and measured values was not directly proportional to the snow accumulation but was related to the seasonal air temperature variations and the intensity of the local surface inversion; and (iv) the averaged corrected air temperature was higher than the measured values except during the summer when there were days without temperature inversion. The magnitude of the temperature difference between the corrected and measured was mainly determined by snow accumulation and the intensity of the local surface inversion. 相似文献
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基于华东地区3 km分辨率WRF (Weather Research and Forecasting) 模式和高密度地面自动气象站(AWS)观测,研究GSI-3DVAR同化系统的RHZSCL对AWS观测的地面温度和风观测同化的敏感性。结果表明:运用GSI-3DVAR同化地面AWS观测时,RHZSCL的取值较为敏感;选取合适的RHZSCL能有效改进地面分析场精度,相较于背景场地面温度和地面矢量风差(VWD) RMSE均可减小35%以上。当RHZSCL过大会导致温度高、低值中心的影响范围过大,风分析场较为平滑,无法反映出中小尺度环流结构。但RHZSCL过小则会使得温度分析场增加误差,并导致风分析场出现虚假大风。观测密度稀疏化的敏感性试验结果表明,地面温度场及风场所适应的最优RHZSCL皆随着观测密度的增大而相应减小。 相似文献
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人工增雨效果评估中的面雨量计算分析 总被引:2,自引:1,他引:1
选取北京地区两次不同性质降水过程,分别对仅用气候站和并入自动气象站/雨量站的雨量资料,应用算术平均法和泰森多边形法对固定目标区进行面雨量计算分析.结果表明,泰森多边形法在不同性质降水过程面雨量计算中都表现出了一定优越性;并入自动气象站/雨量站的面雨量结果较仅用气候站资料所得结果更具代表性.在人工增雨效果评估中,可以尝试对由气候站计算的面雨量统计订正的办法,较精确地获得历史期目标区(包括控制区)面雨量实际值,这对提高人工增雨效果的评估精度具有重要实用价值. 相似文献
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The accuracy of daily mean 2 meter air temperatures from five reanalyses are assessed against in-situ observations from Automatic Weather Stations in East Antarctica for 2005 to 2008.The five reanalyses all explain more than 70%of the average variance,and have annual root mean square errors(RMSE)between 3.4 and 6.9°C.The NOAA reanalyses,NCEP-1,NCEP-2and 20CRv2,have cool biases of 2.5,1.4 and 1.5°C,respectively.The ERA Interim and JCDAS reanalyses have warm biases of 1.7 and 2.0°C.All reanalyses generally perform better in the austral spring and worse in winter and autumn.They also show the best performance at an inland plateau site at 2800 m elevation,but are worst at Dome A,the summit of the East Antarctic ice sheet.In general,ERA Interim is superior to the other reanalyses,probably because of its 4D assimilation scheme.The three NOAA reanalyses perform worst;Their assimilation scheme is more constrained by limited observations and 20CRv2has less input data,assimilating only surface pressure observations.Despite deficiencies and limitations,the reanalyses are still powerful tools for climate studies in the Antarctic region.However,more in-situ observations are required,especially from the vast interior of Antarctica. 相似文献
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利用2012年5月1日至7月31日全国自动气象站两种来源实时上传资料中的“非缺测不一致”小时降水数据,详查了问题的产生原因,为在实时拼接过程中高效判断数据正确性,提出较小尺度时间序列求证比对模型(IVSA):当同一时间同一台站的两种来源小时降水值发生不一致时,首先在较小时间尺度(分钟级)序列上使用内部一致性检查方法分别求证小时降水的正确性;当各自在较小时间尺度序列均无法证伪时,将单元出错概率引入两分钟降水序列的比对过程,并据此竞优遴选得出较为可靠的小时降水数据。指出:(1)产生非缺测不一致问题的原因主要有生成报文时观测数据不全、报文处理环节不一致、台站信息不正确三类。(2)使用2012年5月1360组实例形成IVSA模型参数后,模型在2012年6—7月的4017组非缺测不一致数据中取得了99.65%的判断准确率。通过IVSA模型,非缺测不一致的小时降水数据取舍问题可在分钟降水序列比对中找出答案。 相似文献