Evaluation of four global reanalysis products using in situ observations in the Amundsen Sea Embayment, Antarctica
Evaluation of four global reanalysis products using in situ observations in the Amundsen Sea Embayment, Antarctica
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DOI：
10.1002/2015jd024680
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发表时间：
2016-06-16
影响因子：
4.4
通讯作者：
Lazzara, M. A.
中科院分区：
文献类型：
--
作者：
Jones, R. W.;Renfrew, I. A.;Lazzara, M. A.
南极洲西部阿蒙森海湾（ASE）内的冰川是南极洲退缩最快的冰川之一。气象再分析产品被广泛用于帮助理解和模拟导致这种撤退的过程。在这里，我们对ASE区域内四种最新的全球再分析产品的观测结果进行了评估--欧洲中期天气预报中心中期再分析（ERA-I）、日本55年再分析（JRA-55）、气候预报系统再分析（CFSR）和现代研究与应用回顾分析（MERRA）。这些观测数据来自四个自动气象站、三艘研究船巡航以及一套新的38个无线电探空仪，全部在2009-2014年期间进行。所有四次再分析产生的2 m温度场都比AWS观测值冷，偏差从大约-1.8 ℃（ERA-I）到-6.8 ℃（MERRA）不等。在阿蒙森海，空间平均夏季偏差在-0.4摄氏度（JRA-55）和-2.1摄氏度（MERRA）之间，在所有再分析中，靠近大陆的冷偏差明显较大（高达-6摄氏度）。所有四个再分析都低估了高风速（>15 m s（-1））下的近地面风速，并在特定湿度下表现出干偏差和相对较大的均方根误差（RMSE）。与无线电探空仪探测结果的比较表明，冷，干燥的偏差在地面延伸到对流层低层，这里ERA-I和CFSR再分析提供了最准确的配置文件。当观测到逆温时，再分析通常包含较大的温度和湿度偏差（以及RMSE），当观测到低空急流时，再分析通常包含较大的风速偏差（类似于2至3 m s（-1））。
The glaciers within the Amundsen Sea Embayment (ASE), West Antarctica, are amongst the most rapidly retreating in Antarctica. Meteorological reanalysis products are widely used to help understand and simulate the processes causing this retreat. Here we provide an evaluation against observations of four of the latest global reanalysis products within the ASE region-the European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-I), Japanese 55-year Reanalysis (JRA-55), Climate Forecast System Reanalysis (CFSR), and Modern Era Retrospective-Analysis for Research and Applications (MERRA). The observations comprise data from four automatic weather stations (AWSs), three research vessel cruises, and a new set of 38 radiosondes all within the period 2009-2014. All four reanalyses produce 2 m temperature fields that are colder than AWS observations, with the biases varying from approximately -1.8 degrees C (ERA-I) to -6.8 degrees C (MERRA). Over the Amundsen Sea, spatially averaged summertime biases are between -0.4 degrees C (JRA-55) and -2.1 degrees C (MERRA) with notably larger cold biases close to the continent (up to -6 degrees C) in all reanalyses. All four reanalyses underestimate near-surface wind speed at high wind speeds (>15 m s(-1)) and exhibit dry biases and relatively large root-mean-square errors (RMSE) in specific humidity. A comparison to the radiosonde soundings shows that the cold, dry bias at the surface extends into the lower troposphere; here ERA-I and CFSR reanalyses provide the most accurate profiles. The reanalyses generally contain larger temperature and humidity biases, (and RMSE) when a temperature inversion is observed, and contain larger wind speed biases (similar to 2 to 3 m s(-1)), when a low-level jet is observed.