Artifacts in Century‐Length Atmospheric and Coupled Reanalyses Over Antarctica Due To Historical Data Availability
Artifacts in Century‐Length Atmospheric and Coupled Reanalyses Over Antarctica Due To Historical Data Availability
复制标题
DOI：
10.1002/2017gl076226
复制
发表时间：
2018-01
影响因子：
5.2
通讯作者：
D. Schneider;R. Fogt
中科院分区：
文献类型：
--
作者：
D. Schneider;R. Fogt
在数据同化和历史观测数字化的推动下，跨越整个二十世纪的大气再分析产品在观测稀少的高纬度南半球提供了宝贵的网格化数据。在这里，比较了三次再分析中的南半球夏季和冬季地面气压趋势与基于统计的气压重建的趋势、没有数据同化的大气模式的趋势以及再分析的不确定性估计。在20世纪初的南半球夏季，重新分析低估了绕极槽的深度，导致该地区上空出现错误的高压值。在1950年前后，同化气压观测次数的迅速增加导致再分析标准误差的急剧减少和地面气压的虚假下降。重建提供了更可能的该地区地面气压的历史，这与没有资料同化的模式模拟是一致的。
Enabled by advances in data assimilation and the digitization of historical observations, atmospheric reanalysis products that span the entire twentieth century provide valuable gridded data over the sparsely observed high‐latitude Southern Hemisphere. Here austral summer and winter surface pressure trends in three reanalyses are compared to trends in a statistically based pressure reconstruction, trends in atmospheric models without data assimilation, and estimates of uncertainty from the reanalyses. In austral summer during the early twentieth century, the reanalyses underestimate the depth of the circumpolar trough, leading to erroneously high pressure values over the region. Around 1950, a rapid increase in the number of assimilated pressure observations leads to a dramatic reduction in the reanalyses standard error and a spurious drop in the surface pressure. A more likely history of the surface pressure over this region is provided by the reconstruction, which is consistent with the model simulations without data assimilation.