Effect of global and regional SST biases on the East Asian Summer Monsoon in the MetUM GA7 and GC3 configurations
Effect of global and regional SST biases on the East Asian Summer Monsoon in the MetUM GA7 and GC3 configurations
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DOI：
10.1007/s00382-023-06954-w
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发表时间：
2023-10
期刊：
影响因子：
4.6
通讯作者：
Armenia Franco-Díaz;N. Klingaman;Andrew G. Turner;B. Dong;Liang Guo
中科院分区：
文献类型：
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作者：
Armenia Franco-Díaz;N. Klingaman;Andrew G. Turner;B. Dong;Liang Guo
利用气象局全球大气统一模式7.0（GA 7）和全球耦合模式3.0（GC 3）的气候长度试验，对东亚夏季风（EASM）的观测和再分析结果进行了评价。结果表明，系统的模式偏差，如高估了中国南方的降雨量和低估了中国北方的降雨量，这表明季风没有足够的北渗透。我们评估了区域误差在海表温度（SST）的条件下，在三个地区：太平洋，印度洋和大西洋的EASM的影响。全球SST偏差在GC 3配置实质上改变了东亚夏季风的季节循环：东亚夏季风在早/中季风季节向北推进较晚，季风提前消退，这也减少了中国北方大部分地区的降水。东亚夏季风季节性降水偏置与西北太平洋副热带高压位置和强度的变化有关，而西北太平洋副热带高压位置和强度的变化与局地蒸发和水汽输送向华南的偏置有关。厄尔尼诺-南方涛动（ENSO）和印度洋偶极子（IOD）遥相关路径中的GC 3偏差也影响东亚夏季风偏差。GC 3偏置减弱了ENSO与东亚夏季风的遥相关，并导致中国东南部在厄尔尼诺发展期间出现强的干偏置。
Climate-length experiments of the Met Office Unified Model Global Atmosphere 7.0 (GA7) and Global Coupled 3.0 (GC3) configurations are evaluated against observations and reanalyses for the simulation of the East Asian summer monsoon (EASM). The results show systematic model biases, such as overestimated rainfall over southern China and underestimated rainfall over northern China, suggesting a monsoon that does not penetrate northward enough. We evaluate the effects on the EASM of regional errors in sea-surface temperature (SST) conditions in three regions: the Pacific, the Indian, and the Atlantic Oceans. The global SST biases in GC3 configuration substantially shift the EASM seasonal cycle: a late northward progression of the EASM in the early/mid-monsoon season, and an early retreat of the monsoon that also reduces rainfall over most of northern China. The EASM seasonal rainfall bias in the EASM region is linked to changes in the locations and strength of the western North Pacific subtropical high, which is associated with biases in local evaporation and moisture transport towards South China. GC3 biases in the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) teleconnection pathways also influence the EASM biases. GC3 biases weaken the ENSO teleconnection to the EASM and cause a strong dry bias in southeast China during developing El Niño.