Quasi-stationary extratropical wave trains associated with distinct tropical Pacific seasonal mean convection patterns: observational and AMIP model results
Quasi-stationary extratropical wave trains associated with distinct tropical Pacific seasonal mean convection patterns: observational and AMIP model results
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与不同热带太平洋季节性平均对流模式相关的准稳态温带波列：观测和 AMIP 模型结果
DOI：
10.1007/s00382-019-04882-2
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发表时间：
2019-08
期刊：
影响因子：
4.6
通讯作者：
Ma Tianjiao
中科院分区：
文献类型：
--
作者：
Ding Shuoyi;Chen Wen;Graf Hans F;Chen Zhang;Ma Tianjiao
本文似稳温带波浪的形成机制与四个不同的冬天季节平均热带太平洋对流异常模式,包括西方CP (W-CP)模式,拉尼娜现象(LN)模式,CP厄尔尼诺(CPEN)模式和EP厄尔尼诺(EPEN)模式,研究了利用观测大气模型和六个相互比对项目阶段5 (AMIP5)高技能模型(ACCESS1.0、CanAM4 CCSM4, CMCC-CM, HadGEM2-A,MPI-ESM-LR)数据集。观测结果表明，热带太平洋强迫诱发高层异常罗斯比波源，通过调制局地Hadley环流迫使北太平洋中部涡度，激发准静止行星波向东传播，穿透北大西洋，最终通过局地天气涡旋-平均流相互作用在中高纬度地区建立相关远相关。不同的波列结构可能是由热带太平洋不同的对流异常引起的温带涡度强迫在强度和尺度上的明显差异所解释的。MME结果进一步证实了观测得到的可能的物理过程，但仍存在一些显著差异。这些覆盖了北太平洋和北美，可能是由于模式对温带涡度强迫和局地风暴路径强度的模拟能力。此外，平流层-对流层相互作用对温带大气环流异常起着重要作用。平流层极涡不仅调节下伏波列，特别是北大西洋/欧洲扇区的下伏波列，而且还通过上升波活动通量受到高纬度对流层上层扰动的影响。
In this paper, mechanisms for the formation of quasi-stationary extratropical wave trains associated with four distinct winter patterns of seasonal mean tropical Pacific convection anomalies, including the western CP (W-CP) pattern, La Niña (LN) pattern, CP El Niño (CPEN) pattern and EP El Niño (EPEN) pattern, are investigated by utilizing observational and six Atmospheric Model Intercomparison Project Phase 5 (AMIP5) high-skilled models (ACCESS1.0, CanAM4, CCSM4, CMCC-CM, HadGEM2-A, MPI-ESM-LR) datasets. The observational results show that tropical Pacific forcing induces upper-level anomalous Rossby wave source that force vorticity over the central North Pacific through modulating the local Hadley circulation, then excite eastward propagation of quasi-stationary planetary waves penetrating into the North Atlantic, and finally establish the associated teleconnections in mid- and high-latitudes by local synoptic eddy–mean flow interaction. Different structures of wave trains may be explained by evident differences in intensity and scale of the extratropical vorticity forcing originating from distinct convection anomalies over the tropical Pacific. The MME results further confirm the possible physical processes obtained from observations, but there still exist some significant differences. These cover the North Pacific and North America and can possibly be attributed to the models’ simulation ability of extratropical vorticity forcing and local storm track intensity. In addition, the stratosphere–troposphere interaction plays an important role for extratropical atmospheric circulation anomalies. The stratospheric polar vortex not only modulates the underlying wave train, especially for the North Atlantic/Europe sector, but is also affected by the upper-tropospheric disturbance in high-latitudes through the upward wave activity flux.
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