Large-scale atmospheric circulation and global sea surface temperature associations with Horn of Africa June-September rainfall

2009 ◽  
Vol 29 (8) ◽  
pp. 1075-1100 ◽  
Author(s):  
Zewdu T. Segele ◽  
Peter J. Lamb ◽  
Lance M. Leslie
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Sea Surface ◽  
Horn Of Africa ◽  
Large Scale Atmospheric Circulation ◽  
Global Sea Surface Temperature

scholarly journals Seasonal-to-Interannual Variability of Ethiopia/Horn of Africa Monsoon. Part I: Associations of Wavelet-Filtered Large-Scale Atmospheric Circulation and Global Sea Surface Temperature

2009 ◽  
Vol 22 (12) ◽  
pp. 3396-3421 ◽  
Author(s):  
Zewdu T. Segele ◽  
Peter J. Lamb ◽  
Lance M. Leslie
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Atmospheric Circulation ◽  
Time Scales ◽  
Time Scale ◽  
Climate System ◽  
Sea Surface ◽  
Horn Of Africa ◽  
Annual Mode ◽  
Global Sea Surface Temperature

Abstract Horn of Africa rainfall varies on multiple time scales, but the underlying climate system controls on this variability have not been examined comprehensively. This study therefore investigates the linkages between June–September Horn of Africa (especially Ethiopian) rainfall and regional atmospheric circulation and global sea surface temperature (SST) variations on several key time scales. Wavelet analysis of 5-day average or monthly total rainfall for 1970–99 identifies the dominant coherent modes of rainfall variability. Several regional atmospheric variables and global SST are then identically wavelet filtered, based on the rainfall frequency bands. Regression, correlation, and composite analyses are subsequently used to identify the most important rainfall–climate system time-scale relationships. The results show that Ethiopian monsoon rainfall variation is largely linked with annual time-scale atmospheric circulation patterns involving variability in the major components of the monsoon system. Although variability on the seasonal (75–210 days), quasi-biennial (QB; 1.42–3.04 yr), and El Niño–Southern Oscillation (ENSO; 3.04–4.60 yr) time scales accounts for much less variance than the annual mode (210 days–1.42 yr), they significantly affect Ethiopian rainfall by preferentially modulating the major regional monsoon components and remote teleconnection linkages. The seasonal time scale largely acts in phase with the annual mode, by enhancing or reducing the lower-tropospheric southwesterlies from the equatorial Atlantic during wet or dry periods. The wet QB phase strengthens the Azores and Saharan high and the tropical easterly jet (TEJ) over the Arabian Sea, while the wet ENSO phase enhances the Mascarene high, the TEJ, and the monsoon trough more locally. The effects of tropical SST on Ethiopian rainfall also are prominent on the QB and ENSO time scales. While rainfall–SST correlations for both the QB and ENSO modes are strongly positive (negative) over the equatorial western (eastern) Pacific, only ENSO exhibits widespread strong negative correlations over the Indian Ocean. Opposite QB and ENSO associations tend to characterize dry Ethiopian conditions. The relationships identified on individual time scales now are being used to develop and validate statistical prediction models for Ethiopia.

scholarly journals Changes in sea-surface temperature and atmospheric circulation patterns associated with reductions in Arctic sea ice cover in recent decades

2018 ◽  
Vol 18 (19) ◽  
pp. 14149-14159 ◽  
Author(s):  
Lejiang Yu ◽  
Shiyuan Zhong
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
The Arctic ◽  
Atmospheric Circulation Patterns ◽  
Arctic Sea

Abstract. In recent decades, the Arctic sea ice has been declining at a rapid pace as the Arctic warms at a rate of twice the global average. The underlying physical mechanisms for the Arctic warming and accelerated sea ice retreat are not fully understood. In this study, we apply a relatively novel statistical method called self-organizing maps (SOM) along with composite analysis to examine the trend and variability of autumn Arctic sea ice in the past three decades and their relationships to large-scale atmospheric circulation changes. Our statistical results show that the anomalous autumn Arctic dipole (AD) (Node 1) and the Arctic Oscillation (AO) (Node 9) could explain in a statistical sense as much as 50 % of autumn sea ice decline between 1979 and 2016. The Arctic atmospheric circulation anomalies associated with anomalous sea-surface temperature (SST) patterns over the North Pacific and North Atlantic influence Arctic sea ice primarily through anomalous temperature and water vapor advection and associated radiative feedback.

The influence of global sea surface temperature variability on the large-scale land surface temperature

2014 ◽  
Vol 44 (7-8) ◽  
pp. 2159-2176 ◽  
Author(s):  
Nicholas L. Tyrrell ◽  
Dietmar Dommenget ◽  
Claudia Frauen ◽  
Scott Wales ◽  
Mike Rezny
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Large Scale ◽  
Temperature Variability ◽  
Sea Surface ◽  
Large Scale Land ◽  
Global Sea Surface Temperature
Sign in / Sign up

Export Citation Format

Share Document