Analysis of Climate Change Indices in Musanze District, Rwanda

Abstract

This study used daily rainfall, minimum temperature, and maximum temperature data from the Rwanda Meteorology Agency (Meteo Rwanda) for the years 1983 - 2016 to analyze climate change indices in the Musanze district of Rwanda. Rainfall and temperature extreme indices were determined using the methodology provided by Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI). Climate Data Tool (CDT), which is R-based package developed by International Research Institute for Climate and Society (IRI) was used to compute the indices. Sen's slope estimator and the modified Mann-Kendall (m-MK) test were both applied to identify trends and determine the degree of change. The Monthly Temperature (TXx, TXn, TNx, and TNn) indices generally showed a warming in the eastern and a cooling in the western parts of the district, according to the trend results; however, the Minimum tail of temperature indices showed a slightly reduced cooling which is a sign of warm nights and hot days in highland areas of volcanic region. For the same period, the district's eastern regions have higher precipitation intensity and wetness, which gradually declines toward the middle and western regions. In addition, a considerable upward trend in the annual total precipitation for days above the 95th percentile (very wet days) and the annual count for precipitation equal or greater than 20 mm (very heavy precipitation days). Additionally, temperature indices showed a large rise in the minimum and maximum values of daily minimum temperatures, annual minimum and maximum values of daily maximum temperatures, and the percentage of days with daily maximum temperatures above the 90th percentile (warm days). In view of these evolving trends in weather and climate patterns, the study recommends local farmers and other stakeholders involved in socioeconomic activities in the district to implement the necessary climate change mitigation and adaptation measures.