Assessing the impact of El Niño–Southern Oscillation on South African temperatures during austral summer

Lakhraj‐Govender, Rakhee; Grab, Stefan

doi:10.1002/joc.5791

Cited by 23 publications

(20 citation statements)

References 49 publications

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“…The central interior (coinciding with our CSub region) experiences the strongest ENSO‐related temperature response, followed by the northern interior (coinciding with our NESA region); in contrast, the northeastern interior (coinciding with our ESA region) records the strongest temperature responses during La Niña events (Lakhraj‐Govender and Grab, 2018). It has also been identified that responses to ENSO events are usually most pronounced during austral summer (Nicholson and Kim, 1997; Mason, 2001; Lakhraj‐Govender and Grab, 2018). The SSTs generated in our study suggest a likeness to La Niña conditions following each of the four eruptions, which could contribute to the cooler temperatures over southern Africa.…”

Section: Discussionmentioning

confidence: 79%

“…Our findings thus demonstrate strongly contrasting temperature responses to volcanic forcing between the more continental climatic/summer rainfall regions (CSub, NESA), and the Mediterranean/subtropical climates of the winter/all year rainfall regions (i.e., SWC/ECC respectively). Strong El Niño Southern Oscillation (ENSO) phases tend to have more significant temperature effects over the interior than coastal regions of southern Africa, with the CSub and NESA regions most strongly impacted by the El Niño anomaly, and result in positive temperature departures (Lakhraj‐Govender and Grab, 2018). The somewhat weaker responses along coastal regions (ECC and SWC) may also be due to oceanic temperature‐regulating effects, particularly the cool Benguela current that borders the SWC (Philippon et al ., 2012).…”

Section: Discussionmentioning

confidence: 99%

“…The southern African climate is strongly controlled by ENSO (Pezza et al ., 2007; Philippon et al ., 2012), which is known to have variable sub‐regional climatic impacts across the sub‐continent (Nicholson and Kim, 1997; Mason, 2001; Lakhraj‐Govender and Grab, 2018). The central interior (coinciding with our CSub region) experiences the strongest ENSO‐related temperature response, followed by the northern interior (coinciding with our NESA region); in contrast, the northeastern interior (coinciding with our ESA region) records the strongest temperature responses during La Niña events (Lakhraj‐Govender and Grab, 2018). It has also been identified that responses to ENSO events are usually most pronounced during austral summer (Nicholson and Kim, 1997; Mason, 2001; Lakhraj‐Govender and Grab, 2018).…”

Section: Discussionmentioning

confidence: 99%

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Southern African temperature responses to major volcanic eruptions since 1883: Simulated by CMIP5 models

Harvey

Grab

2021

Intl Journal of Climatology

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Although volcanic forcing impacts on climate have gained much international attention during recent years, focus has largely been at hemispheric scale, and most particularly on the Northern Hemisphere (NH). Here we investigate the impact of major volcanic eruptions since 1883 on southern African climate, with a view to establishing potential sub‐regional differences across a variety of temporal scales. To this end, we use historical simulations from the Coupled Model Intercomparison Project, Phase 5 (CMIP5) to study near‐surface temperature responses to four major eruptions (Krakatau, 1883; Santa Maria, 1902; Agung, 1963; Pinatubo, 1991) over six sub‐regions of southern Africa. Results show significant cooling across all sub‐regions after each eruption. However, we detect considerable sub‐regional differences in the amplitude, timing and duration of responses. For instance, stronger temperature departures occur in northern rather than southern sub‐regions where diurnal and annual temperature ranges are normally greater. While significant responses occur within the first year after each eruption, there is a more delayed response in three of the sub‐regions (southwestern coast and central southern Africa) following the Santa Maria eruption. Strongest responses follow the Krakatau eruption in all sub‐regions, while the weakest response follows the Santa Maria eruption in western sub‐regions and the Agung eruption in eastern sub‐regions. Most regions experience the strongest temperature departures during austral autumn and winter (MAM and JJA), and weakest during spring (SON).

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Section: Discussionmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Southern African temperature responses to major volcanic eruptions since 1883: Simulated by CMIP5 models

Harvey

Grab

2021

Intl Journal of Climatology

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“…A range of studies have shown that ENSO events significantly impact global weather and climatic variables [9][10][11][12][13][14][15][16][17][18]. For instance, Rishma and Katpatal [17] reported that the average rainfall during El Niño years was less than it was during La Niña and normal years in central India.…”

Section: Introductionmentioning

confidence: 99%

“…Since ENSO signals have strong teleconnection impacts on climate variables, which can substantially regulate crop production in some regions of the world [14,16,[23][24][25][26][27][28]. As each crop requires a cardinal temperature and a specific amount of rainfall for its proper growth and development.…”

Section: Introductionmentioning

confidence: 99%

Remote Impacts from El Niño and La Niña on Climate Variables and Major Crops Production in Coastal Bangladesh

et al. 2021

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El Niño and La Niña Southern Oscillation (ENSO) are major drivers that affect climatic variables in many countries. Therefore, ENSO mediated variation in climatic factors have significant consequences for crop production. We studied ENSO mediated variations in temperature and rainfall in the five coastal districts of Bangladesh during 1951–2017, and the impacts on major crops production were analyzed using growing degree day (GDD) index. Statistical analyses were performed on different climatic parameters in relation to ENSO events and locations. Results indicate that ENSO events had significant influence on monthly, seasonal and annual temperature and rainfall amounts (p < 0.05). Specifically, maximum temperature under ENSO phases were higher during Kharif-I and Kharif-II seasons than neutral years. In contrast, the minimum temperature was higher in neutral years than ENSO events during Rabi season. Averaged across stations, annual mean maximum temperature was 0.5 and 0.23 °C higher during El Niño and La Niña compared to neutral years. Rainfall was higher during neutral years compared to El Niño and La Niña. These changes in seasonal temperature variably changed crop GDD in different locations and thus, crop growth duration and crop yield. Therefore, this study provides a general understanding to ENSO mediated impacts on coastal agriculture in Bangladesh.

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Spatiotemporal characteristics of human thermal comfort across southern Africa: An analysis of the Universal Thermal Climate Index for 1971–2021

Roffe

Walt

Fitchett

2023

Intl Journal of Climatology

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The 6th Assessment of the Intergovernmental Panel on Climate Change projects increasing thermal-associated morbidity and mortality under anthropogenically induced warming. Over 100 indices exist to quantify thermal stress, and among these, the Universal Thermal Climate Index (UTCI) was developed for regional investigations of thermal stress influences on human health. Although by definition a universal index, current applications are mainly limited to Europe. For regions such as Africa, use of the UTCI has been hampered by a lack of available requisite input variables from ground-based meteorological stations. To overcome this, a gridded dataset, derived from ERA5 reanalysis, of UTCI equivalent temperatures was developed by the European Centre for Medium-Range Weather Forecasts. Using this dataset for daily average, minimum and maximum UTCI values, we explore spatiotemporal patterns and changes thereof over annual, seasonal, and monthly scales across southern Africa from 1979 to 2021. Across these scales, 9 of 10 UTCI thermal stress categories were observed, ranging from very strong cold stress to extreme heat stress. Spatially, no thermal stress was most widespread for daily mean values, whereas for daily maximum (minimum) values there was a wider heat (cold) stress incidence, with frequent occurrences of moderate and strong heat stress (slight and moderate cold stress). Interannually, a clear El Niño-Southern Oscillation influence on thermal stress was evident during summer, with El Niño (La Niña) phases extending (reducing) heat stress incidences by up to 13.8% (2.9%). Over the study period, heat stress increased at statistically significant rates in many instances, with the strongest, most widespread increases, for the daily average and maximum (minimum), during spring (summer), averaging 0.28 and 0.29 CÁdecade −1 (0.23 CÁdecade −1 ); few regions experienced statistically significant decreasing trends. Overall, the trend results highlight regions vulnerable to significant thermal climate changes, and thus should be considered in decision-making regarding outdoor activities.

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Assessing the impact of El Niño–Southern Oscillation on South African temperatures during austral summer

Cited by 23 publications

References 49 publications

Southern African temperature responses to major volcanic eruptions since 1883: Simulated by CMIP5 models

Southern African temperature responses to major volcanic eruptions since 1883: Simulated by CMIP5 models

Remote Impacts from El Niño and La Niña on Climate Variables and Major Crops Production in Coastal Bangladesh

Spatiotemporal characteristics of human thermal comfort across southern Africa: An analysis of the Universal Thermal Climate Index for 1971–2021

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