Temperature variability in coastal Ghana: a day-to-day variability framework

Day-to-day temperature variability (DTD) is observed to have negative effects on people and their activities. The study assessed DTD in nine areas in coastal Ghana. The study used daily maximum (T-max) and minimum (T-min) temperatures from 1981-2021, obtained from the Ghana Meteorological Agency (GMet) and the National Aeronautics and Space Administration/Prediction of Worldwide Energy Resources (NASA/POWER). The ERA5 hourly data on single levels from 1940 to present, obtained from the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis, was further utilised to validate the NASA/POWER and the GMet datasets. The standard deviation (SD), DTD, the ratio of DTD to SD (G), the change in DTD (Delta DTD), threshold exceedances (2 degrees C and 4 degrees C), and the linear regression test were the statistical methods applied. Results established that an orderly climate (G < 1) exists in the nine areas. The highest monthly averages Delta DTD were observed in Ada Foah, Apam, and Elmina, while the lowest occurred in Denu, Keta, and Saltpond. Throughout the year, Ada Foah had the most exceedances of the 2 degrees C and 4 degrees C thresholds in DTD, except for the 4 degrees C DTD T-min, where Cape Coast was higher. Temporal trends increased in both DTD T-max and T-min. However, improvements in DTD T-min were weak. DTD was higher in the dry season (November-March) than in the wet season (May-July) due to higher insolation and seasonal wind developments. A continuous increase in DTD could affect the health of the people in coastal Ghana.