Multidecadal see-saw of the impact of ENSO on Indian and West African summer monsoon rainfall

Srivastava, Gaurav; Chakraborty, Arindam; Nanjundiah, Ravi S.

doi:10.1007/s00382-018-4535-2

Cited by 35 publications

(31 citation statements)

References 59 publications

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“…In addition, Srivastava et al . () found similar multidecadal evolution in the teleconnection between ATL3 and West Africa Monsoon (WAM) rainfall. They showed that after 1980, El Niño (La Niña) tend to occur simultaneously with negative (positive) ATL3 and this in turn reduced (enhanced) WAM by increased south‐westerly moisture flux.…”

Section: Changes In the Relationships Between Gha Rainfall And Remotementioning

confidence: 73%

Revisiting interannual to decadal teleconnections influencing seasonal rainfall in the Greater Horn of Africa during the 20th century

Bahaga

Fink

Knippertz

2019

Intl Journal of Climatology

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This paper revisits teleconnections for three major rainy seasons at the Greater Horn of Africa for the period 1901–2013. Sea surface temperature‐based climate indices known to influence Short, Kiremt, and Long Rains are used in a comprehensive statistical analysis to detect non‐stationary behaviour in teleconnections and to split them into interannual and decadal time scales. Physical mechanisms are proposed for identified significant non‐stationary teleconnections. Interannual variability in the October–December Short Rains is predominantly influenced by the Indian Ocean Dipole (IOD) with a percent variance explained (PVE) of up to 80% in recent years. However, abrupt shifts in this teleconnection occurred around 1918, 1951, 1987, and recently. The Short Rains also correlate strongly with El Niño‐Southern Oscillation (ENSO). However, ENSO influence on Short Rains is mediated by in‐phase occurrence of IOD. Decadal variations in Short Rains are more directly explained by low‐frequency variability in the Pacific Ocean (PO). A hitherto undocumented non‐stationary relation was found between Atlantic Niño 3 and June–September Kiremt Rains. The non‐stationarity seems to be related to a decadal regime shift in the West African monsoon system in the late 1960s. The variability of Kiremt Rains is also strongly associated with ENSO, although the recent increased correlation is not non‐stationary. Consistent with recent studies, the post‐1998 March–May Long Rains decline is strongly associated with decadal variability in the PO. The PVEs in the stable correlations using Pacific Decadal Oscillation and Interdecadal Pacific Oscillation indices range from 25 to 64%, mostly due to low‐frequency variability (>8 years). The results have ramifications for seasonal‐to‐decadal forecasting and can be taken to design modelling studies to gain insights into the physical mechanisms.

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Section: Changes In the Relationships Between Gha Rainfall And Remotementioning

confidence: 73%

Revisiting interannual to decadal teleconnections influencing seasonal rainfall in the Greater Horn of Africa during the 20th century

Bahaga

Fink

Knippertz

2019

Intl Journal of Climatology

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“…Several previous studies have shown that there is existence of significant simultaneous covariability of ENSO with West African rainfall [80,103,104]. One of the possible teleconnection mechanisms that could explain the ENSO influence on West Africa rainfall is the eastward shift of the Walker circulation and subsequent decent over the Afro-Asia during the El Niño events [104].…”

Section: Discussionmentioning

confidence: 97%

Study on Temporal Variations of Surface Temperature and Rainfall at Conakry Airport, Guinea: 1960–2016

Loua

Benchérif

Mbatha

et al. 2019

Climate

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The monthly averaged data time series of temperatures and rainfall without interruption of Conakry Airport (9.34° N 13.37° W, Guinea) from 1960 to 2016 were used. Inter-annual and annual changes in temperature and rainfall were investigated. Then, different models: Mann-Kendall Test, Multi-Linear-Regression analysis, Theil-Sen’s slope estimates and wavelet analysis where used for trend analysis and the dependency with these climate forcings. Results showed an increase in temperature with semi-annual and annual cycles. A sharp and abrupt rise in the temperature in 1998 was found. The results of study have shown increasing trends for temperature (about 0.21°/year). A decrease in rainfall (about −8.14 mm/year) is found since the end of 1960s and annual cycle with a maximum value of about 1118.3 mm recorded in August in average. The coherence between the two parameters and climate indices: El Niño 3.4, Atlantic Meridional Mode, Tropical Northern Atlantic and Atlantic Niño, were investigated. Thus, there is a clear need for increased and integrated research efforts in climate parameters variations to improve knowledge in climate change.

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“…Several studies investigated the interdecadal variations in the relationship between ISMR and ENSO (Ju & Slingo, 1995;Krishnamurthy & Goswami, 2000;Torrence & Webster, 1999;Srivastava et al, 2018;Webster & Yang, 1992). Using century-long observational data sets, Kumar et al (1999) have shown a weakening of ENSO-ISMR relationship in the recent period.…”

Section: Introductionmentioning

confidence: 99%

Atlantic Zonal Mode: An Emerging Source of Indian Summer Monsoon Variability in a Warming World

Sabeerali

Ajayamohan

Bangalath

et al. 2019

Geophysical Research Letters

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Atlantic Zonal Mode (AZM) and Indian summer monsoon rainfall (ISMR) are known to have an inverse relationship, which means that the cold (warm) phases of AZM result in strong (weak) ISMR. Here, we report that the inverse relationship between AZM and ISMR has significantly strengthened in recent decades. The cause of this strengthening relationship has been investigated. We find a robust increase in interannual variability of sea surface temperature over the eastern tropical Atlantic Ocean in recent decades, which implies an increase in the number of strong AZM events toward the end of the twentieth century. The increase in strong AZM events alters the large‐scale monsoon circulation over the Indian subcontinent by enhancing the Kelvin wave response into the Indian Ocean, leading to an enhanced AZM‐ISMR teleconnection. This demands a better representation of the AZM‐ISMR teleconnection in climate models for improving seasonal monsoon prediction in a warming world.

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Multidecadal see-saw of the impact of ENSO on Indian and West African summer monsoon rainfall

Cited by 35 publications

References 59 publications

Revisiting interannual to decadal teleconnections influencing seasonal rainfall in the Greater Horn of Africa during the 20th century

Revisiting interannual to decadal teleconnections influencing seasonal rainfall in the Greater Horn of Africa during the 20th century

Study on Temporal Variations of Surface Temperature and Rainfall at Conakry Airport, Guinea: 1960–2016

Atlantic Zonal Mode: An Emerging Source of Indian Summer Monsoon Variability in a Warming World

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