“Variability of extreme temperature in Kigali during the recent decades”

Abstract

The climate change is among the main problem the world is facing nowadays. In Rwanda, researches have shown the increase of temperature during the last decades. The observed warming is most likely explained by the growing population accompanied by the increasing emission of greenhouse gases, and the escalating urbanization and industrialization the country has experienced during the last decades, especially in Kigali as country Capital. This study was focused on examining the variability extreme temperature in Kigali during Recent decades. Among 27 climate extreme indices recommended by ETCCDI (Expert team on Climate change detection and Indices), only the indices which could be relevant to Rwanda (especially in Kigali) were selected. The positive trend (Z=4.37) at α = 0.001 level of significance for maximum Temperature and the positive trend (Z= 6.33) at α = 0.001 level of significance for Minimum temperature was found. The slope value was 0.043oC/year for Maximum temperature and 0.056oC/year for Minimum Temperature for the period 1980-2015. More significant positive trend for Minimum temperature was observed compared to Maximum Temperature. Thus, the trend for The Diurnal Temperature Range is negative (Z= -1.16) at significant level greater than 0.1 with the slope value of -0.010oC/year. All temperature indices have shown the significant increase during last recent decades especially indices related to minimum temperature. The increase in warm days and warm nights together with the decrease in cool nights and cool days were observed. In general the results for annual mean Temperature show that the temperature has increased significantly in Kigali in the period 1980-2015 with the slope value of 0.044oC/year. All results show that Kigali has experienced the significant warming during recent decades especially in the last two decades. The observed warming is explained by the increase of urbanization, industrialization, high density of population accompanied with the increase in greenhouse gases emission.