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Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics
Much of the Eastern Cape province in South Africa has been experiencing a severe drought since 2015. This drought has had major socio-economic effects particularly on the large impoverished rural population as well as on some urban areas where supplied water services have broken down in several case...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer Berlin Heidelberg
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7428292/ https://www.ncbi.nlm.nih.gov/pubmed/32836893 http://dx.doi.org/10.1007/s00382-020-05413-0 |
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author | Mahlalela, P. T. Blamey, R. C. Hart, N. C. G. Reason, C. J. C. |
author_facet | Mahlalela, P. T. Blamey, R. C. Hart, N. C. G. Reason, C. J. C. |
author_sort | Mahlalela, P. T. |
collection | PubMed |
description | Much of the Eastern Cape province in South Africa has been experiencing a severe drought since 2015. This drought has had major socio-economic effects particularly on the large impoverished rural population as well as on some urban areas where supplied water services have broken down in several cases. The region is influenced by both midlatitude and tropical systems leading to a complex regional meteorology that hitherto has not been much studied compared to other parts of South Africa. Here, the ongoing drought is examined in the context of long-term trends and the interannual rainfall variability of the region. Although the region has experienced drought in all seasons since 2015, focus here is placed on the spring (September–November) which shows the most consistent and robust signal. On average, this season contributes between about 25–35% of the annual rainfall total. Based on CHIRPS data, it is found that this season shows a significant decreasing trend in both rainfall totals as well as the number of rainfall days (but not heavy rainfall days) for spring over most of the province since 1981. On interannual time scales, the results indicate that dry (wet) springs over the Eastern Cape are associated with a cyclonic (anticyclonic) anomaly southeast of South Africa as part of a shift in the zonal wavenumber 3 pattern in the midlatitudes. Over the landmass, a stronger (weaker) Botswana High is also apparent with increased (decreased) subsidence over and near the Eastern Cape which is less (more) favourable for cloud band development and hence reduced (enhanced) rainfall during dry (wet) springs. Analysis of mid-century (2040–2060) CMIP5 rainfall projections suggests that there may be a flattening of the annual cycle over the Eastern Cape with the winter becoming wetter and the summer drier. For the spring season of interest here, the multi-model projections also indicate drying but less pronounced than that projected for the summer. |
format | Online Article Text |
id | pubmed-7428292 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Springer Berlin Heidelberg |
record_format | MEDLINE/PubMed |
spelling | pubmed-74282922020-08-17 Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics Mahlalela, P. T. Blamey, R. C. Hart, N. C. G. Reason, C. J. C. Clim Dyn Article Much of the Eastern Cape province in South Africa has been experiencing a severe drought since 2015. This drought has had major socio-economic effects particularly on the large impoverished rural population as well as on some urban areas where supplied water services have broken down in several cases. The region is influenced by both midlatitude and tropical systems leading to a complex regional meteorology that hitherto has not been much studied compared to other parts of South Africa. Here, the ongoing drought is examined in the context of long-term trends and the interannual rainfall variability of the region. Although the region has experienced drought in all seasons since 2015, focus here is placed on the spring (September–November) which shows the most consistent and robust signal. On average, this season contributes between about 25–35% of the annual rainfall total. Based on CHIRPS data, it is found that this season shows a significant decreasing trend in both rainfall totals as well as the number of rainfall days (but not heavy rainfall days) for spring over most of the province since 1981. On interannual time scales, the results indicate that dry (wet) springs over the Eastern Cape are associated with a cyclonic (anticyclonic) anomaly southeast of South Africa as part of a shift in the zonal wavenumber 3 pattern in the midlatitudes. Over the landmass, a stronger (weaker) Botswana High is also apparent with increased (decreased) subsidence over and near the Eastern Cape which is less (more) favourable for cloud band development and hence reduced (enhanced) rainfall during dry (wet) springs. Analysis of mid-century (2040–2060) CMIP5 rainfall projections suggests that there may be a flattening of the annual cycle over the Eastern Cape with the winter becoming wetter and the summer drier. For the spring season of interest here, the multi-model projections also indicate drying but less pronounced than that projected for the summer. Springer Berlin Heidelberg 2020-08-14 2020 /pmc/articles/PMC7428292/ /pubmed/32836893 http://dx.doi.org/10.1007/s00382-020-05413-0 Text en © Springer-Verlag GmbH Germany, part of Springer Nature 2020 This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic. |
spellingShingle | Article Mahlalela, P. T. Blamey, R. C. Hart, N. C. G. Reason, C. J. C. Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics |
title | Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics |
title_full | Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics |
title_fullStr | Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics |
title_full_unstemmed | Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics |
title_short | Drought in the Eastern Cape region of South Africa and trends in rainfall characteristics |
title_sort | drought in the eastern cape region of south africa and trends in rainfall characteristics |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7428292/ https://www.ncbi.nlm.nih.gov/pubmed/32836893 http://dx.doi.org/10.1007/s00382-020-05413-0 |
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