Assessing the impact of climate variability on maize yields in the different regions of Ghana—A machine learning perspective

According to the analysis in Table 4, with a mean temperature of 27.42˚C, the Volta region has the highest coefficient of variation (CVar) of 1.19%, while the Upper East region has the highest mean temperature (28.95˚C) of all the regions with a coefficient of variation of 1.03%. This signifies that the temperature in the Volta region experiences more significant fluctua- tions over time compared to other regions. The Upper East region, on the other hand, has the highest mean temperature, indicating that it experiences greater temperature on average than the other regions. However, the coefficient of variation in the Upper East region (1.03%) is lower than in the Volta region (1.19%), indicating that the temperature in the Upper East region is less variable than in the Volta region. In comparison to the other regions, the North- ern, Upper East, and Upper West regions are noted to have higher average temperatures. This is since these areas are in the Guinea Savannah Zone, which is regarded as the warmest region in the nation and does not have frequent rainfall. With a mean precipitation of 950.9 mm, the Greater Accra region has the highest coefficient of variation (CV) of 13.17%, whereas the Western region has the highest mean precipitation of all regions with 1491.63 and a coefficient of variation of 11.39%. That is, the precipitation in the Greater Accra region is more volatile than in the other regions. This means that precipita- tion in the Greater Accra region varies more significantly over time. The Western region, on

the other hand, has the greatest mean precipitation of all the regions, suggesting that it receives more rainfall on average than the other regions. However, the coefficient of variation in the Western region (11.39%) is lower than in the Greater Accra region (13.17%), indicating that precipitation in the Western region is less variable than in the Greater Accra region. The aver- age CO2 level across all regions is 0.39, with a coefficient of variation (CV) of 35.06%. The Table 4. Mean and coefficient of variation analysis of the climate variables. Regions Measures Climate Variables Avg Temp Min Temp Max Temp Precip CO2 Ashanti mean 26.98 22.34 31.67 1316.83 0.39 CVar (%) 0.99 1.18 0.96 10.33 35.06 Volta mean 27.42 22.67 32.22 1238.68 0.39 CVar (%) 1.19 1.57 0.99 12.17 35.06 Eastern mean 27.01 22.39 31.67 1236.59 0.39 CVar (%) 1.08 1.34 0.99 12.34 35.06 Northern mean 28.28 22.69 33.92 1133.44 0.39 CVar (%) 1.01 1.31 0.92 8.52 35.06 Upper East mean 28.95 23.02 34.94 997.57 0.39 CVar (%) 1.03 1.41 0.92 8.92 35.06 Upper West mean 28.61 22.92 34.35 1010.48 0.39 CVar (%) 1.04 1.29 1.00 9.04 35.06 Central mean 26.82 22.98 30.7 1230.02 0.39 CVar (%) 1.00 1.15 0.97 11.93 35.06 Western mean 26.92 22.89 31.01 1491.63 0.39 CVar (%) 0.92 1.07 0.92 11.39 35.06 Brong Ahafo mean 27.39 22.45 32.36 1209.11 0.39 CVar (%) 0.98 1.20 0.94 8.53 35.06 Greater Accra mean 27.34 23.50 31.23 950.9 0.39 CVar (%) 1.08 1.35 0.98 13.17 35.06

Note: The bold values represent the highest and precip represents precipitation. https://doi.org/10.1371/journal.pone.0305762.t004 PLOS ONE Impact of climate variability on maize yields in Ghana PLOS ONE | https://doi.org/10.1371/journal.pone.0305762 June 25, 2024 12 / 24