Performance of the IPCC AR6 models in simulating the relation of the western North Pacific subtropical high to the spring northern tropical Atlantic SST

2020 ◽  
Author(s):  
Shangfeng Chen ◽  
Wen Chen ◽  
Renguang Wu ◽  
Bin Yu ◽  
Linye Song
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Subtropical High ◽  
Tropical Atlantic ◽  
Northern Tropical Atlantic Sst ◽  
Northern Tropical Atlantic

scholarly journals Contribution of Different Time-Scale Variations to the Tropical Cyclogenesis Environment over the Northern Tropical Atlantic and Comparison with the Western North Pacific

2019 ◽  
Vol 32 (19) ◽  
pp. 6645-6661 ◽  
Author(s):  
Xi Cao ◽  
Renguang Wu ◽  
Mingyu Bi ◽  
Xiaoqing Lan ◽  
Yifeng Dai ◽  
...  
Keyword(s):  
Energy Conversion ◽  
North Pacific ◽  
Western North Pacific ◽  
Relative Vorticity ◽  
Specific Humidity ◽  
Tropical Atlantic ◽  
Relative Contribution ◽  
Intraseasonal Variations ◽  
Barotropic Energy Conversion ◽  
Northern Tropical Atlantic

Abstract The present study investigates relative contributions of interannual, intraseasonal, and synoptic variations of environmental factors to tropical cyclone (TC) genesis over the northern tropical Atlantic (NTA) during July–October. Analysis shows that convection, lower-level vorticity, and midlevel specific humidity contribute to TC genesis through intraseasonal and synoptic variations with a larger contribution of the latter. The relative contribution of three components of vertical wind shear depends largely on its magnitude. The contribution of sea surface temperature (SST) to TC genesis is mainly due to the interannual component when total SST is above 27.5°C. The barotropic energy for the development of synoptic-scale disturbances comes mainly from climatological mean flows and intraseasonal wind variations. The proportion of contribution between synoptic and intraseasonal variations of convection, relative vorticity, and specific humidity is larger over the eastern NTA than over the western NTA. The barotropic energy conversion has a larger part related to climatological mean flows and intraseasonal wind variations over the eastern and western NTA, respectively. There are notable differences between the NTA and the western North Pacific (WNP). One is that the relative contribution of synoptic variations of convection, relative vorticity, and specific humidity is larger over the NTA, whereas that of intraseasonal variations is larger over the WNP. The other is that the barotropic energy conversion related to climatological mean flows and intraseasonal wind variations is comparable over the NTA, whereas that related to climatological mean flows is larger over the WNP.

scholarly journals Interannual and interdecadal impact of Western North Pacific Subtropical High on tropical cyclone activity

2020 ◽  
Vol 54 (3-4) ◽  
pp. 2237-2248 ◽  
Author(s):  
Qiong Wu ◽  
Xiaochun Wang ◽  
Li Tao
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Southern Oscillation ◽  
Subtropical High ◽  
Interdecadal Change ◽  
Steering Flow ◽  
The Pacific ◽  
Sea Surface Temperature Anomalies ◽  
Peak Phase

AbstractIn this study, we analyzed the impacts of Western North Pacific Subtropical High (WNPSH) on tropical cyclone (TC) activity on both interannual and interdecadal timescales. Based on a clustering analysis method, we grouped TCs in the Western North Pacific into three clusters according to their track patterns. We mainly focus on Cluster 1 (C1) TCs in this work, which is characterized by forming north of 15° N and moving northward. On interannual timescale, the number of C1 TCs is influenced by the intensity variability of the WNPSH, which is represented by the first Empirical Orthogonal Function (EOF) of 850 hPa geopotential height of the region. The WNPSH itself is modulated by the El Niño–Southern Oscillation at its peak phase in the previous winter, as well as Indian and Atlantic Ocean sea surface temperature anomalies in following seasons. The second EOF mode shows the interdecadal change of WNPSH intensity. The interdecadal variability of WNPSH intensity related to the Pacific climate regime shift could cause anomalies of the steering flow, and lead to the longitudinal shift of C1 TC track. Negative phases of interdecadal Pacific oscillation are associated with easterly anomaly of steering flow, westward shift of C1 TC track, and large TC impact on the East Asia coastal area.

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