Trends in variability and extremes of rainfall and temperature in the cattle corridor of Uganda

Abstract

A study was conducted to determine trends of variability and extremes in rainfall and temperature in order to inform stakeholder’s decisions in planning for appropriate adaptation strategies to climate change. Daily rainfall and temperature data sets from 1961 to 2013 were used. Data were subjected to trend analysis using non-parametric Mann-Kendall tests while rainfall and temperature extremes were derived using RClimdex software. Coefficient of variation (CV) in annual rainfall was 25.3, 12.9 and 16.3 % for Mbarara, Masindi and Soroti respectively. Mean daily maximum temperatures were 26.7, 29.6 and 30.8 oC for Mbarara, Masindi and Soroti respectively. Annual total wet days were increasing but not significant (P>0.05). Consecutive wet days (CWD) were increasing only in Mbarara while consecutive dry days, CDDs revealed weak declining trends in Mbarara and stronger significant increasing trends in Soroti (P<0.05). The number of hot days (TX90p) and warm nights (TN90p) was significantly increasing (P< 0.05) in Mbarara and Masindi. The number of warmest nights (TNx) and hottest days (TXx) was also significantly increasing (P<0.05). Mean diurnal temperature range, DTR showed significant decreasing trends in Mbarara and Masindi (P<0.05) while in Soroti it was significantly increasing. The observed increasing temperatures, coupled with declining CWDs and increasing CDDs will most likely result into increased heat stress to livestock, drying of most surface water sources and changes in pasture species composition thus causing a decline in livestock productivity.

Key words: Climate change and cattle corridor, hot days, trends, wet days