scholarly journals Emergent constraints on future projections of the western North Pacific Subtropical High

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaolong Chen ◽  
Tianjun Zhou ◽  
Peili Wu ◽  
Zhun Guo ◽  
Minghuai Wang
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Subtropical High ◽  
Future Projections ◽  
Emergent Constraints

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.

scholarly journals Enhanced or Weakened Western North Pacific Subtropical High under Global Warming?

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Chao He ◽  
Tianjun Zhou ◽  
Ailan Lin ◽  
Bo Wu ◽  
Dejun Gu ◽  
...  
Keyword(s):  
Global Warming ◽  
North Pacific ◽  
Western North Pacific ◽  
Subtropical High

scholarly journals Impacts of Sea Surface Temperature Uncertainty on the Western North Pacific Subtropical High (WNPSH) and Rainfall

2011 ◽  
Vol 26 (3) ◽  
pp. 371-387 ◽  
Author(s):  
Xiaodong Hong ◽  
Craig H. Bishop ◽  
Teddy Holt ◽  
Larry O’Neill
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Pacific ◽  
Western North Pacific ◽  
Forecast Error ◽  
Error Variance ◽  
Satellite Observations ◽  
Sea Surface ◽  
Subtropical High ◽  
Forecast Error Variance

Abstract This paper examines the sensitivity of short-term forecasts of the western North Pacific subtropical high (WNPSH) and rainfall to sea surface temperature (SST) uncertainty using the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS). A comparison of analyzed SSTs with satellite observations of SST indicates that SST analysis errors are particularly pronounced on horizontal scales from 100 to 200 km, similar to the mesoscale eddy scales in the Kuroshio region. Since significant oceanic variations occur on these scales, it is of interest to examine the effects of representing this small-scale uncertainty with random, scale-dependent perturbations. An SST ensemble perturbation generation technique is used here that enables temporal and spatial correlations to be controlled and produces initial SST fields comparable to satellite observations. The atmospheric model develops large uncertainty in the Korea and Japan area due to the fluctuation in the horizontal pressure gradient caused by the location of the WNPSH. This, in turn, increases the variance of the low-level jet (LLJ) over southeast China, resulting in large differences in the moist transport flux from the tropical ocean and subsequent rainfall. Validation using bin-mean statistics shows that the ensemble forecast with the perturbed SST better distinguishes large forecast error variance from small forecast error variance. The results suggest that using the SST perturbation as a proxy for the ocean ensemble in a coupled atmosphere and ocean ensemble system is feasible and computationally efficient.

scholarly journals Using eddy geopotential height to measure the western North Pacific subtropical high in a warming climate

2016 ◽  
Vol 131 (1-2) ◽  
pp. 681-691 ◽  
Author(s):  
Chao He ◽  
Ailan Lin ◽  
Dejun Gu ◽  
Chunhui Li ◽  
Bin Zheng ◽  
...  
Keyword(s):  
North Pacific ◽  
Geopotential Height ◽  
Western North Pacific ◽  
Subtropical High ◽  
Warming Climate

scholarly journals Tropical Cloud Cluster Environments and Their Importance for Tropical Cyclone Formation

2019 ◽  
Vol 32 (13) ◽  
pp. 4069-4088 ◽  
Author(s):  
Hsu-Feng Teng ◽  
Cheng-Shang Lee ◽  
Huang-Hsiung Hsu ◽  
James M. Done ◽  
Greg J. Holland
Keyword(s):  
Tropical Cyclone ◽  
Environmental Conditions ◽  
North Pacific ◽  
Western North Pacific ◽  
Subtropical High ◽  
Low Latitude ◽  
Brightness Temperatures ◽  
Cloud Cluster ◽  
Potential Index ◽  
Circulation Patterns

Abstract This study uses a nonhierarchical cluster analysis to identify the major environmental circulation patterns associated with tropical cloud cluster (TCC) formation in the western North Pacific. All TCCs that formed in July–October 1981–2009 are examined based on their 850-hPa wind field around TCC centers. Eight types of environmental circulation patterns are identified. Of these, four are related to monsoon systems (trough, confluence, north of trough, and south of trough), three are related to easterly systems (low-latitude zone, west of subtropical high, and southwest of subtropical high), and one is associated with low-latitude cross-equatorial flow. The genesis potential index (GPI) is analyzed to compare how favorable the environmental conditions are for tropical cyclone (TC) formation when TCCs form. Excluding three cluster types with the GPI lower than the climatology of all samples, TCCs formed in monsoon environments have larger sizes, lower brightness temperatures, longer lifetimes, and higher GPIs than those of TCCs formed in easterly environments. However, for TCCs formed in easterly environments, the average GPI for those TCCs that later develop into TCs (developing TCCs) is higher than that for other TCCs (nondeveloping TCCs). This difference is nonsignificant for TCCs formed in monsoon environments. Conversely, the average magnitudes of GPI are similar for developing TCCs, regardless of whether TCCs form in easterly or monsoon environments. In summary, the probability of a TCC to develop into a TC is more sensitive to the environmental conditions for TCCs formed in easterly environments than those formed in monsoon environments.

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