Decadal variability of summer Southern African rainfall

Bastien Dieppois; B. Pohl; M. Rouault; M. New; N. Keenlyside; Damian Lawler

Decadal variability of summer Southern African rainfall

Bastien Dieppois, B. Pohl, M. Rouault, M. New, N. Keenlyside, Damian Lawler

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Abstract

Summer Southern African rainfall exhibit three significant timescales of variability over the 20th century: interdecadal (15–28 year), quasi-decadal (8–13 year) and interannual (2–8 year). Teleconnections with global sea-surface temperature and atmospheric circulation anomalies are different for each timescale. Interdecadal fluctuations in summer rainfallI are associated with the Pacific Decadal Oscillation (PDO), while quasi-decadal and interannual fluctuations are related to decadal ENSO-like, often described as the Interdecadal Pacific Oscillation (IPO), and ENSO. Annular geopotential anomalies related the Pacific SST influence strongly interact with those driven by the Southern Annular Mode (SAM). Shifts in the westerlies thus lead to anomalous low-level easterly moisture fluxes from the Mascarene region even though decadal timescales, which are not significantly expressed in the SAM.

Original language	English
Title of host publication	SASAS 2015
Subtitle of host publication	Applying the weather
Publisher	South African Society for Atmospheric Sciences
Volume	31
Publication status	Published - 2015
Event	SASAS 2015: Applying the Weather - Pretoria, South Africa Duration: 21 Sept 2015 → 22 Sept 2015 Conference number: 31

Conference

Conference	SASAS 2015
Country/Territory	South Africa
City	Pretoria
Period	21/09/15 → 22/09/15

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Cite this

@inproceedings{ea9f2250f64f45c8b81d08cfe1deffaf,

title = "Decadal variability of summer Southern African rainfall",

abstract = "Summer Southern African rainfall exhibit three significant timescales of variability over the 20th century: interdecadal (15–28 year), quasi-decadal (8–13 year) and interannual (2–8 year). Teleconnections with global sea-surface temperature and atmospheric circulation anomalies are different for each timescale. Interdecadal fluctuations in summer rainfallI are associated with the Pacific Decadal Oscillation (PDO), while quasi-decadal and interannual fluctuations are related to decadal ENSO-like, often described as the Interdecadal Pacific Oscillation (IPO), and ENSO. Annular geopotential anomalies related the Pacific SST influence strongly interact with those driven by the Southern Annular Mode (SAM). Shifts in the westerlies thus lead to anomalous low-level easterly moisture fluxes from the Mascarene region even though decadal timescales, which are not significantly expressed in the SAM.",

author = "Bastien Dieppois and B. Pohl and M. Rouault and M. New and N. Keenlyside and Damian Lawler",

year = "2015",

language = "English",

volume = "31",

booktitle = "SASAS 2015",

publisher = "South African Society for Atmospheric Sciences",

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note = "SASAS 2015 : Applying the Weather ; Conference date: 21-09-2015 Through 22-09-2015",

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TY - GEN

T1 - Decadal variability of summer Southern African rainfall

AU - Dieppois, Bastien

AU - Pohl, B.

AU - Rouault, M.

AU - New, M.

AU - Keenlyside, N.

AU - Lawler, Damian

N1 - Conference code: 31

PY - 2015

Y1 - 2015

N2 - Summer Southern African rainfall exhibit three significant timescales of variability over the 20th century: interdecadal (15–28 year), quasi-decadal (8–13 year) and interannual (2–8 year). Teleconnections with global sea-surface temperature and atmospheric circulation anomalies are different for each timescale. Interdecadal fluctuations in summer rainfallI are associated with the Pacific Decadal Oscillation (PDO), while quasi-decadal and interannual fluctuations are related to decadal ENSO-like, often described as the Interdecadal Pacific Oscillation (IPO), and ENSO. Annular geopotential anomalies related the Pacific SST influence strongly interact with those driven by the Southern Annular Mode (SAM). Shifts in the westerlies thus lead to anomalous low-level easterly moisture fluxes from the Mascarene region even though decadal timescales, which are not significantly expressed in the SAM.

AB - Summer Southern African rainfall exhibit three significant timescales of variability over the 20th century: interdecadal (15–28 year), quasi-decadal (8–13 year) and interannual (2–8 year). Teleconnections with global sea-surface temperature and atmospheric circulation anomalies are different for each timescale. Interdecadal fluctuations in summer rainfallI are associated with the Pacific Decadal Oscillation (PDO), while quasi-decadal and interannual fluctuations are related to decadal ENSO-like, often described as the Interdecadal Pacific Oscillation (IPO), and ENSO. Annular geopotential anomalies related the Pacific SST influence strongly interact with those driven by the Southern Annular Mode (SAM). Shifts in the westerlies thus lead to anomalous low-level easterly moisture fluxes from the Mascarene region even though decadal timescales, which are not significantly expressed in the SAM.

M3 - Conference proceeding

VL - 31

BT - SASAS 2015

PB - South African Society for Atmospheric Sciences

T2 - SASAS 2015

Y2 - 21 September 2015 through 22 September 2015

ER -

Decadal variability of summer Southern African rainfall

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