Evaluation of ocean data assimilation in CAS-ESM-C: Constraining the SST field
Evaluation of ocean data assimilation in CAS-ESM-C: Constraining the SST field
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DOI：
10.1007/s00376-016-5234-8
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发表时间：
2016-07-01
影响因子：
5.8
通讯作者：
Lu, Zeting
中科院分区：
文献类型：
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作者：
Dong, Xiao;Lin, Renping;Lu, Zeting
建立了弱耦合同化系统，通过集合最优插值方案将海表温度观测同化到耦合气候模式（CASESM-C）中。该系统是历史气候模拟的有用工具，显示出巨大的优势，包括保持大气反馈、防止海洋区域远离观测等。在耦合模型积分过程中，与未同化场相比，分析中的地表和地下海洋场的偏差都可以减少。根据系统 30 个模型年的输出，评估了气候系统的气候学和年际变率。结果表明，该系统能够合理地再现气候全球降水量和海平面气压，但仍然存在双ITCZ问题。此外，系统还基本再现了厄尔尼诺演化过程中与ENSO相关的地表气温、位势高度和降水量所揭示的ENSO足迹。该系统还可以在北太平洋西部地区的年际和季节内时间尺度上很好地模拟观测到的海温与降雨的关系，其中大气反馈对于气候模拟至关重要。
A weakly coupled assimilation system, in which SST observations are assimilated into a coupled climate model (CASESM-C) through an ensemble optimal interpolation scheme, was established. This system is a useful tool for historical climate simulation, showing substantial advantages, including maintaining the atmospheric feedback, and keeping the oceanic fields from drifting far away from the observation, among others. During the coupled model integration, the bias of both surface and subsurface oceanic fields in the analysis can be reduced compared to unassimilated fields. Based on 30 model years of output from the system, the climatology and interannual variability of the climate system were evaluated. The results showed that the system can reasonably reproduce the climatological global precipitation and SLP, but it still suffers from the double ITCZ problem. Besides, the ENSO footprint, which is revealed by ENSO-related surface air temperature, geopotential height and precipitation during El Nio evolution, is basically reproduced by the system. The system can also simulate the observed SST-rainfall relationships well on both interannual and intraseasonal timescales in the western North Pacific region, in which atmospheric feedback is crucial for climate simulation.