Spatio-temporal evolution of surface temperature trends in Ghana (1983-2021): a multi-station approach

TL;DR

This study provides a detailed, high-resolution analysis of temperature trends across Ghana from 1983 to 2021, revealing localized and seasonal warming patterns with implications for climate adaptation policies.

Contribution

It introduces a granular, station-level spatio-temporal analysis of Ghana's temperature trends using rigorous quality control and robust statistical methods, highlighting asymmetric warming.

Findings

Minimum temperatures are rising faster than maximum temperatures.

Temperature trends are highly localized and seasonal.

The diurnal temperature range is narrowing, affecting agriculture and health.

Abstract

Surface temperature is a fundamental Essential Climate Variable, serving as a primary indicator of climate change and exerting a profound influence on ecosystems, agriculture, and human livelihoods. Although existing research provides a foundation for understanding the climate of Ghana, there remains an opportunity to enhance this landscape with granular station-level analysis. Such high-resolution analysis complements existing studies by capturing localised climatic nuances. This study conducts a detailed spatio-temporal analysis of temperature trends across 22 meteorological stations from 1983 to 2021. Using daily maximum (Tmax) and minimum (Tmin) observations, data were subjected to quality control, homogeneity testing, and homogenisation according to World Meteorological Organisation (WMO) standards, using AgERA5 reanalysis as a reference.The significance and magnitude of trends were determined using the Modified Mann-Kendall test, which is robust in handling potential effects of autocorrelation, and Sen's slope estimator. Results revealed that temperature trends in Ghana are highly localised and seasonal, highlighting the necessity for more studies of this nature. A critical finding is the asymmetric warming across the country, with minimum temperatures rising at an accelerated rate compared to maximum temperatures. This narrowing of the diurnal temperature range poses significant threats to agricultural stability and public health because nocturnal cooling is diminished. These findings underscore the urgent need for site-specific, seasonal climate monitoring to inform customised adaptation strategies. To mitigate these impacts, the study recommends a robust policy framework focusing on afforestation and the transition to green energy.