Subseasonal Influences of Teleconnection Patterns on the Boreal Wintertime Surface Air Temperature over Southern China as Revealed from Three Reanalysis Datasets

Shi Shi,Zhang Zhang,Suolangtajie Suolangtajie,Wang Wang

doi:10.3390/atmos10090514

Shi Shi, Zhang Zhang + Show 2 more

Open Access

https://doi.org/10.3390/atmos10090514

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Abstract

The daily fields from three reanalysis datasets are utilized to explore the subseasonal influence of teleconnection patterns on the surface air temperature (SAT) over southern China. Due to the similarity of the results from the different datasets, the ensemble mean is then used in this study. After applying the false discovery rate to the significance test, the composite results reveal that positive Western Pacific (WP) events, East Atlantic (EA) events, Scandinavian (SCA) events, and Eastern Atlantic/Western Russia (EAWR) events are the teleconnection events that have an influence on SAT anomalies over southern China. The timing of inducing significant SAT anomalies over southern China is similar among positive WPevents, EA events and EAWR events, i.e., approximately the first 5-day period after their peak day. In contrast, SCA events exert a lagged significant influence on SAT, i.e., during approximately the second 6-day period after their peak day. Therefore, considering that significant circulation anomalies generally begin to appear at least 4 days before the peak day, these teleconnection events could be used as subseasonal predictors for SAT anomalies over southern China.

Highlights

Extratropic teleconnection patterns in the Northern Hemisphere were first systematically proposed by Wallace and Gutzler [1] through the grid point–based correlation coefficients of the monthly 500 hPa geopotential height (Z500), i.e., Western Atlantic, East Atlantic (EA), Eurasian (EU), Pacific/NorthAmerican (PNA), and Western Pacific (WP) patterns
The results show that the evolution features of the two indices match quite well, except for the stronger values of the WP index
The background potential temperature shows an overall southwestward gradient direction, with a clockwise rotation when approaching southern China. Under such a background potential temperature, once the anticyclonic circulation is induced to the northeast of the Tibetan Plateau, it can advect the cold background potential temperature southwestward, leading to a southeastward/southward propagation of the negative potential temperature anomaly along the northeastern slope of the plateau, which acts as propagation of the thermal Rossby wave [18]

Summary

Introduction

Extratropic teleconnection patterns in the Northern Hemisphere were first systematically proposed by Wallace and Gutzler [1] through the grid point–based correlation coefficients of the monthly 500 hPa geopotential height (Z500), i.e., Western Atlantic, East Atlantic (EA), Eurasian (EU), Pacific/NorthAmerican (PNA), and Western Pacific (WP) patterns. Extratropic teleconnection patterns in the Northern Hemisphere were first systematically proposed by Wallace and Gutzler [1] through the grid point–based correlation coefficients of the monthly 500 hPa geopotential height (Z500), i.e., Western Atlantic, East Atlantic (EA), Eurasian (EU), Pacific/North. By using rotated principal component analysis (RPCA) on the monthly 700 hPa geopotential height, Horel [2] and Barnston and Livezey [3] proposed nine winter teleconnection patterns in the Northern Hemisphere: North Atlantic oscillation (NAO), EA, EU type 1, EU type 2, Northern Asian, WP, Eastern Pacific (EP), PNA, and tropical/Northern. Pacific and North Atlantic, some extratropic teleconnection patterns could be identified, e.g., PNA, WP, NAO, and EA. The two types in the EU in [3] are referred to as the Scandinavian (SCA)

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