This study evaluates the tropical cyclone (TC) activity in two high‐resolution data sets—MERRA‐2 Reanalysis (Modern‐Era Retrospective Analysis for Research and Applications, Version 2) and MERRA‐2 AMIP (Atmospheric Model Intercomparison Project). These data sets use the same atmospheric model, the Goddard Earth Observing System Model, Version 5 (GEOS‐5) during the same period. However, while MERRA‐2 AMIP is a free‐running atmospheric simulation forced only with sea surface temperature (SST), MERRA‐2 Reanalysis uses an advanced data assimilation system to include a large variety of data sets. Thus, we analyze (1) the sensitivity of TC activity to the model forcing, (2) how well the TCs in both data sets replicate observed TC characteristics, (3) the sensitivity of these results to tracking schemes and thresholds. Standard diagnostics such as the number of tropical cyclones and their intensity distribution are very similar in the AMIP model and the reanalysis. TCs in both data sets are weaker than observed, as is typical for the spatial resolution of these global models. Overall, the use of data assimilation in the MERRA‐2 Reanalysis does not lead to a significantly better TC climatology than in AMIP. Furthermore, comparison of the MERRA‐2 Reanalysis to two other reanalysis data sets shows that MERRA‐2 generates fewer, but more intense TCs, than those reanalysis products.

中文翻译：

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MERRA-2再分析和AMIP模拟中的热带气旋特征

这项研究在两个高分辨率数据集中评估了热带气旋（TC）的活动-MERRA-2再分析（研究和应用的现代时代回顾分析，第2版）和MERRA-2 AMIP（大气模型比对项目）。这些数据集在同一时期使用相同的大气模型，即戈达德地球观测系统模型，版本5（GEOS-5）。但是，尽管MERRA-2 AMIP是仅靠海面温度（SST）强制进行的自由运行的大气模拟，但MERRA-2 Reanalysis使用高级数据同化系统来包含各种数据集。因此，我们分析了（1）TC活动对模型强迫的敏感性；（2）两个数据集中的TC复制观察到的TC特性的程度如何；（3）这些结果对跟踪方案和阈值的敏感性。在AMIP模型和重新分析中，诸如热带气旋的数量及其强度分布之类的标准诊断非常相似。这两个数据集中的TC都比观测到的弱，这是这些全局模型的空间分辨率所特有的。总体而言，在MERRA-2重新分析中使用数据同化不会比AMIP带来显着更好的TC气候。此外，将MERRA-2再分析与其他两个再分析数据集进行比较后发现，与那些再分析产品相比，MERRA-2产生的TC更少，但强度更大。在MERRA-2重新分析中使用数据同化方法不会比AMIP显着改善TC气候。此外，将MERRA-2再分析与其他两个再分析数据集进行比较后发现，与那些再分析产品相比，MERRA-2产生的TC更少，但强度更大。在MERRA-2重新分析中使用数据同化方法不会比AMIP显着改善TC气候。此外，将MERRA-2再分析与其他两个再分析数据集进行比较后发现，与那些再分析产品相比，MERRA-2产生的TC更少，但强度更大。