A Global Perspective of Tropical Cyclone Precipitation in Reanalyses
A Global Perspective of Tropical Cyclone Precipitation in Reanalyses
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DOI：
10.1175/jcli-d-20-0892.1
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发表时间：
2021-11-01
影响因子：
4.9
通讯作者：
Parfitt, Rhys
中科院分区：
文献类型：
--
作者：
Jones, Evan;Wing, Allison A.;Parfitt, Rhys
本研究比较了8个不同再分析数据集（NCEP-CFSR，ERA-20 C，ERA-40，ERAS，ERA-Interim，JRA-55，MERRA-2和NOAA-20 C）的气候学热带气旋（TC）降水的传播。TC降水是通过每个TC中心固定的500公里半径使用手动跟踪分配的。再分析捕获类似的一般空间模式的TC降水和TC降水分数，定义为分配给TC的年度降水的分数，在TC降水的蔓延是大于整个再分析的总降水的蔓延。TC降水相对于再分析间平均TC降水的扩散，或相对扩散，在东太平洋比在西太平洋大。按再分析强度划分，TC降水中再分析的最大相对分布来自高强度TC。与卫星观测相比，再分析表明，在大多数地区的气候平均年TC降水量较低。区域平均降水率在TC复合再分析强度的比较表明，跨再分析的传播是更大的强度TC。对TC降水分配对跟踪方法的敏感性检验表明，人工跟踪分配的TC降水量明显大于客观跟踪分配的TC降水量。然而，当TC降水由TC密度归一化时，这种趋势被最小化。总的来说，再分析中的TC降水不仅受到水平输出分辨率或任何TC预处理的影响，而且还受到数据同化和参数化方案的影响。结果表明，需要改进的代表性的TC和它们的降水再分析，以提高整体降水。
This study compares the spread in climatological tropical cyclone (TC) precipitation across eight different reanalysis datasets: NCEP-CFSR, ERA-20C, ERA-40, ERAS, ERA-Interim, JRA-55, MERRA-2, and NOAA-20C. TC precipitation is assigned using manual tracking via a fixed 500-km radius from each TC center. The reanalyses capture similar general spatial patterns of TC precipitation and TC precipitation fraction, defined as the fraction of annual precipitation assigned to TCs, and the spread in TC precipitation is larger than the spread in total precipitation across reanalyses. The spread in TC precipitation relative to the inter-reanalysis mean TC precipitation, or relative spread, is larger in the east Pacific than in the west Pacific. Partitioned by reanalysis intensity, the largest relative spread across reanalyses in TC precipitation is from high-intensity TCs. In comparison with satellite observations, reanalyses show lower climatological mean annual TC precipitation over most areas. A comparison of area-averaged precipitation rate in TCs composited over reanalysis intensity shows the spread across reanalyses is larger for higher intensity TCs. Testing the sensitivity of TC precipitation assignment to tracking method shows that climatological mean annual TC precipitation is systematically larger when assigned via manual tracking versus objective tracking. However, this tendency is minimized when TC precipitation is normalized by TC density. Overall, TC precipitation in reanalyses is affected by not only horizontal output resolution or any TC preprocessing, but also data assimilation and parameterization schemes. The results indicate that improvements in the representation of TCs and their precipitation in reanalyses are needed to improve overall precipitation.