Variability properties of daily and monthly observed near-surface temperatures in Uganda : 1960-2008

Abstract

Variability and trends in daily and monthly near-surface temperatures in Uganda, collected over the period 1960–2008 (49 years), are analysed. For this purpose, daily observational maximum and minimum temperature records from eight selected stations in Uganda were acquired from the Uganda Meteorological Department (UMD). Data collected by the UMD are quality controlled through a rigorous process before being archived. The data received were tested for homogeneity, gaps were filled and correlation analyses were used for validation of area average series. Statistical techniques (e.g. Mann–Kendall and Linear Regression) were employed to analyse temperature variability and to obtain temperature trends. Findings indicate that intra-annual temperature shows reduced variability over recent decades, but which is not statistically significant. Results also demonstrated that maximum temperatures are more variable compared to minimum temperatures in Uganda. An increasing trend in hot days, hot nights, warm nights and warm spells were also detected. At seven of the stations, annual temperature range and diurnal temperature range trends were found to be negative. The finding that intra-annual and intra-monthly variance is declining suggests that fewer anomalously extreme temperature episodes occur. The gap between maximum and minimum extremes is reducing, which supports the observation that minimum temperatures are on the increase.