Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)

The monitoring of rainfall variability over recent decades has become a necessity due to its devastating effects such as floods and droughts, which render humans vulnerable across different parts of the West African region. The current study seeks to provide a good understanding of variability withi...

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Main Authors: Mohammed Braimah, Vincent A. Asante, Maureen A. Ahiataku, Samuel O. Ansah, Frederick Otu-Larbi, Bashiru Yahaya, John B. Ayabilah, Francis Nkrumah
Format: Article
Language:English
Published: Wiley 2022-01-01
Series:Advances in Meteorology
Online Access:http://dx.doi.org/10.1155/2022/1861130
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author Mohammed Braimah
Vincent A. Asante
Maureen A. Ahiataku
Samuel O. Ansah
Frederick Otu-Larbi
Bashiru Yahaya
John B. Ayabilah
Francis Nkrumah
author_facet Mohammed Braimah
Vincent A. Asante
Maureen A. Ahiataku
Samuel O. Ansah
Frederick Otu-Larbi
Bashiru Yahaya
John B. Ayabilah
Francis Nkrumah
author_sort Mohammed Braimah
collection DOAJ
description The monitoring of rainfall variability over recent decades has become a necessity due to its devastating effects such as floods and droughts, which render humans vulnerable across different parts of the West African region. The current study seeks to provide a good understanding of variability within the minor rainfall season over southern Ghana by employing statistical tools to quantify variability in rainfall. Daily rainfall data from 1981 to 2018 for seventeen (17) synoptic weather stations across southern Ghana are used for this analysis. We perform trend and descriptive statistics of rainfall amount and extreme indices intending to identify the areas with the greatest variability in rainfall. Further, for five recent years (2014–2018), we do an interpolation of the ground station rainfall data and compute anomalies. We find increasing trends of rainfall in the minor rainy season for 16 out of the 17 stations, with rainfall increasing between 0.10 mm and 4.30 mm each season. For extreme rainfall indices, the 17 stations show nonsignificant trends of very wet and extremely wet days. We also find that the middle parts of Ghana have the highest rainfall amounts (262.7 mm/season–400.2 mm/season), while the East Coast has the lowest (125.2 mm/season–181.8 mm/season). Over the whole of southern Ghana, we find high variability in rainfall amount with the coefficient of variations (CV) between 25.3% and 70.8% and moderate to high variability in rainfall frequency (CV = 14.0%–48.8%). The results of rainfall anomalies show that the middle parts had an above-normal rainfall amount. In the same period, the transition areas experienced below-normal rainfall. Our finding of high variability in the minor rainfall season has implications for agricultural productivity in Ghana and countries in the West African region, which rely heavily on rain-fed agriculture. Hence, this study recommends more research to understand the causes of variability in the West African monsoon and how this will change in the region.
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spelling doaj-art-3bf3389ab0c6440b99d3eb4652a3e3242025-08-20T03:55:41ZengWileyAdvances in Meteorology1687-93172022-01-01202210.1155/2022/1861130Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)Mohammed Braimah0Vincent A. Asante1Maureen A. Ahiataku2Samuel O. Ansah3Frederick Otu-Larbi4Bashiru Yahaya5John B. Ayabilah6Francis Nkrumah7Ghana Meteorological AgencyGhana Meteorological AgencyGhana Meteorological AgencyGhana Meteorological AgencyGhana Meteorological AgencyGhana Meteorological AgencyGhana Meteorological AgencyDepartment of PhysicsThe monitoring of rainfall variability over recent decades has become a necessity due to its devastating effects such as floods and droughts, which render humans vulnerable across different parts of the West African region. The current study seeks to provide a good understanding of variability within the minor rainfall season over southern Ghana by employing statistical tools to quantify variability in rainfall. Daily rainfall data from 1981 to 2018 for seventeen (17) synoptic weather stations across southern Ghana are used for this analysis. We perform trend and descriptive statistics of rainfall amount and extreme indices intending to identify the areas with the greatest variability in rainfall. Further, for five recent years (2014–2018), we do an interpolation of the ground station rainfall data and compute anomalies. We find increasing trends of rainfall in the minor rainy season for 16 out of the 17 stations, with rainfall increasing between 0.10 mm and 4.30 mm each season. For extreme rainfall indices, the 17 stations show nonsignificant trends of very wet and extremely wet days. We also find that the middle parts of Ghana have the highest rainfall amounts (262.7 mm/season–400.2 mm/season), while the East Coast has the lowest (125.2 mm/season–181.8 mm/season). Over the whole of southern Ghana, we find high variability in rainfall amount with the coefficient of variations (CV) between 25.3% and 70.8% and moderate to high variability in rainfall frequency (CV = 14.0%–48.8%). The results of rainfall anomalies show that the middle parts had an above-normal rainfall amount. In the same period, the transition areas experienced below-normal rainfall. Our finding of high variability in the minor rainfall season has implications for agricultural productivity in Ghana and countries in the West African region, which rely heavily on rain-fed agriculture. Hence, this study recommends more research to understand the causes of variability in the West African monsoon and how this will change in the region.http://dx.doi.org/10.1155/2022/1861130
spellingShingle Mohammed Braimah
Vincent A. Asante
Maureen A. Ahiataku
Samuel O. Ansah
Frederick Otu-Larbi
Bashiru Yahaya
John B. Ayabilah
Francis Nkrumah
Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)
Advances in Meteorology
title Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)
title_full Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)
title_fullStr Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)
title_full_unstemmed Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)
title_short Variability of the Minor Season Rainfall over Southern Ghana (1981–2018)
title_sort variability of the minor season rainfall over southern ghana 1981 2018
url http://dx.doi.org/10.1155/2022/1861130
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