Assessing the Contributions of Local and East Pacific Warming to the 2015 Droughts in Ethiopia and Southern Africa

Funk, Chris; Harrison, L.; Shukla, Shraddhanand; Korecha, Diriba; Magadzire, Tamuka; Husak, G. J.; Galu, Gideon; Hoell, Andrew

doi:10.1175/bams-d-16-0167.1

Cited by 52 publications

(64 citation statements)

References 14 publications

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“…In general, seasonal CHIRPS rainfall performance is similar to the GPCC (Funk et al, ). The box shown in Figure a was based on the region with the highest DJF rainfall (CHIRPS) correlation with Niño 3.4 SST (Funk et al, ; ). The regions drawn in Figure b,c represent homogenous areas that tend to exhibit coherent EA droughts.…”

Section: Resultsmentioning

confidence: 99%

“…CHIRPS data was used from 1981, and prior values were estimated via regressions with GPCC or Centennial Trends data. For EA, the CHIRPS and Centennial Trends datasets benefit from a fairly large number of additional stations, obtained from national meteorological agencies and the Florida State University archives (Funk et al, ).…”

Section: Resultsmentioning

confidence: 99%

“…Here, we explore CAM5 circulations associated with the 1981–2016 unusually warm SST events (Figure j–l) associated with the seasons marked with circles in Figure g–i. Figure j is similar to a canonical ENSO pattern (Rasmusson and Carpenter, ) that extends across the eastern Pacific, a pattern associated with substantial drying over SA (Ratnam et al, ; Funk et al, ; ). Figure k identifies increased WEP SST and warmer conditions over the South Pacific Convergence Zone (SPCZ).…”

Section: Resultsmentioning

confidence: 99%

“…The 1‐in‐6 year frequency was used because it corresponds to moderate‐to‐strong El Niño events and a return period typical of severe SA and EA droughts. The 1‐in‐6 frequency selection was developed in our previous analyses attribution studies focusing on the 2015–2016 El Niño (Funk et al, ; ; ). It is well‐established that El Niño events occur with a 3‐to‐7 year periodicity.…”

Section: Methods and Datamentioning

confidence: 99%

“…Recognition of the emergent La Niña teleconnection (Williams and Funk, ) helped FEWS NET to provide effective early warning for the 2010/2011 EA drought (Hillbruner and Moloney, ). Furthermore, recognition of the important role played by western Pacific SST and the West Pacific Warming Mode (Funk et al, ; Funk and Hoell, ; ) formed the basis of effective predictions of the 2016 OND and 2017 MAM droughts (Funk, ; Funk et al, ; ).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Examining the role of unusually warm Indo‐Pacific sea‐surface temperatures in recent African droughts

Funk

Harrison

Shukla

et al. 2018

Quart J Royal Meteoro Soc

Self Cite

112

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Southern Africa (SA) and eastern Africa (EA) experienced a sequence of severe droughts in December–February (SA DJF) 2015–2016, October–December (EA OND) 2016 and March–April–May 2017 (EA MAM). This sequence contributed to severe food insecurity. While climate variability in these regions is very complex, the goal of this study is to analyse the role played by unusually warm Indo–Pacific SSTs, where unusual is defined as a 1‐in‐6 year event. We use observed sea‐surface temperatures (SST) and satellite–gauge rainfall observations, a 20‐member ensemble of Community Atmospheric Model version 5.1 simulations (CAM5), and a 40‐member ensemble of climate change simulations from the Community Earth Systems Model version 1 (CESM1) Large Ensemble Community Project (LENS) to explore climate conditions associated with warm events identified based on eastern and western Pacific SSTs. Our analysis suggests that strong El Niño's may be followed by warm western Pacific SST conditions, which can lead to conditions conducive to successive and potentially predictable droughts in SA DJF, EA OND and EA MAM. We show that different regions of warm SST are related to recent droughts—SA DJF: Niño 3.4; EA OND: western equatorial Pacific (WEP); and EA MAM: western North Pacific (WNP). For DJF and MAM, respectively, the CAM5 model driven with observed SST and the same model driven within a climate change experiment indicate that warmer El Niño's and WNP events produce more intense atmospheric responses, potentially associated with more severe droughts. OND climate seems to be strongly influenced by the Indian Ocean Dipole, which corresponds with some WEP events. Given global warming, we suggest that the extreme Niño 3.4 and west Pacific SST events responsible for 2015–2017 droughts are likely to reoccur, thus humanitarian agencies should prepare to predict and respond to multi‐year drought and substantial food insecurity in SA and EA.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methods and Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Examining the role of unusually warm Indo‐Pacific sea‐surface temperatures in recent African droughts

Funk

Harrison

Shukla

et al. 2018

Quart J Royal Meteoro Soc

Self Cite

112

View full text Add to dashboard Cite

show abstract

On the relative influences of different ocean basin sea surface temperature anomalies on southern African rainfall in 20th and 21st century general circulation model simulations

Lickley

Solomon

2018

Intl Journal of Climatology

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Southern Africa rainfall (SAR) is generally projected to decrease during the 21st century as a result of climate change, although there is some disagreement regarding the location and magnitude of this reduction in general circulation models (GCMs). Here we examine the robustness of the rainfall response to sea surface temperature (SST) anomalies. Previous work argues that warmer SSTs in the Indian Ocean suppress SAR. Other studies argue that El Niño leads to suppressed SAR. We examine the SAR response to SST anomalies in the Indian Ocean, Atlantic Ocean, and Niño3.4 region both in observations and in two large ensembles of GCMs run over the 20th and 21st century. We find that El Niño–Southern Oscillation (ENSO) SSTs are most correlated with SAR, while correlations between SAR and the Indian Ocean are dominated by their respective responses to ENSO. This relationship appears to persist under a warming background state.

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Evolution and copula modelling of drought duration and severity over Africa using CORDEX‐CORE regional climate models

Olusegun

Ogunjo

Olusola

2023

Intl Journal of Climatology

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This study assessed the dependence of drought severity and duration across four subregions (Southern, Western, Eastern and Central) in Africa using copula modelling. The analysis was carried out for the reference period 1991–2020 and the future period 2071–2099. Simulated daily precipitation at a horizontal resolution of 0.22° were obtained from three regional climate models (RCMs) participating in the Coordinated Output for Regional Evaluations within the Coordinated Regional Downscaling Experiment (CORDEX‐CORE). The RCMs were downscaled by three global climate models and validated using three high‐resolution gridded daily precipitation products obtained from The Climate Hazards Group InfraRed Precipitation with Stations data (CHIRPS), Climate Prediction Center Africa Rainfall Climatology Version 2.0 (CPC‐ARC2) and Tropical Applications of Meteorology using SATellite data and ground‐based observations (TAMSAT). Comparison of precipitation from the RCMs with the three gridded reference observations shows relatively good performance across the different regions with median value within the range of 3–5 mm·day−1 in Central Africa, 1.5–4.5 mm·day−1 in Western Africa, 1.8–2.8 mm·day−1 in Eastern Africa and 0.5–2.2 mm·day−1 in Southern Africa. On the other hand, the correlation values of drought duration–severity from CORDEX‐CORE models in the different regions of Africa exhibit predominantly strong values greater than 0.8 for both historical and projected climate. The analysis also considered two families of copulas: Archimedean (Frank, Clayton, Gumbel) and Elliptical (Gaussian, Student's t). The performance of the copula functions were estimated using the Akaike information criteria (AIC). Generally, there is a good agreement in the distribution of observed precipitation among the three observational data products across the subregion of Africa, with slight differences attributed to the different processing algorithms of the products. Across West Africa, mean precipitation values from CPC, CHIRPS and TAMSAT was 2.86, 3.16 and 3.07 mm·day−1, respectively. The CCLM‐NCC underestimated the mean values of precipitation reported in the observation data, while CCLM‐MPI and CCLM‐HAD overestimated the mean values of precipitation in the West Africa region.

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Assessing the Contributions of Local and East Pacific Warming to the 2015 Droughts in Ethiopia and Southern Africa

Cited by 52 publications

References 14 publications

Examining the role of unusually warm Indo‐Pacific sea‐surface temperatures in recent African droughts

Examining the role of unusually warm Indo‐Pacific sea‐surface temperatures in recent African droughts

On the relative influences of different ocean basin sea surface temperature anomalies on southern African rainfall in 20th and 21st century general circulation model simulations

Evolution and copula modelling of drought duration and severity over Africa using CORDEX‐CORE regional climate models

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