Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana
| Autor: | Samuel Nii Ardey Codjoe, Ernest O. Asare, Leonard K. Amekudzi, Jeffrey N. A. Aryee, Kwasi Preko, Michael Baidu, Edmund I. Yamba |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
2. Zero hunger
Wet season Hydrology climate variability Atmospheric Science 010504 meteorology & atmospheric sciences Rain gauge Range (biology) wavelet analysis 0207 environmental engineering Late onset 02 engineering and technology 01 natural sciences Disease control Geography length of rainy season 13. Climate action Wavelet power spectrum Coastal zone onset and cessation lcsh:Q 020701 environmental engineering lcsh:Science 0105 earth and related environmental sciences |
| Zdroj: | Climate, Vol 3, Iss 2, Pp 416-434 (2015) Climate Volume 3 Issue 2 Pages 416-434 |
| ISSN: | 2225-1154 |
| Popis: | This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970–2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225–240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210–220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170–225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140–180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5–25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2–8- and 2–4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2–4 and 4–8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socio-economic activities and food security in Ghana. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|