Trends of Extreme Events in Precipitation and Temperature during the 1963 - 2012 Period at Mt Makulu, Zambia

Abstract

The Expert Team on Sector-specific Climate Indices (ET-SCI) for daily temperature and precipitation were analyzed for Mt Makulu (Latitude: 15.550° S, Longitude: 28.250° E, Elevation: 1200 meter) in Zambia. The study objective was to evaluate the ET-SCI climate indices for extreme weather conditions on temperature and precipitation from 1963 to 2012. Quality and homogeneity of the time series data were checked using RHtestsV4 and RHtests_dlyPrcp while ClimPACT2 software package was used to compute the ET-SCI indices. The Mann-Kendall for annual maximum and mean temperature were statistically significant with a positive linear trend (p<0.05). Additionally, results showed a significant increase in absolute indices as a function of temperature. The maximum warmest daily temperature (TXx) index showed a predominant increase in the monthly and annual maximum value of daily maximum temperature at Mt Makulu. The minimum warmest daily temperature (TXn) showed a similar trend for the annual value. Results also showed that the daily mean temperature (TMm) and mean daily maximum temperature (TXm) had increased from 1963 - 2012. The Daily Temperature Range (DTR) significantly increased annually and monthly resulting in a linear slope of 0.031 and 0.003, respectively. SU (Number of days when TX > 25°C) for both monthly and annual trend had increased significantly with a slope of 1.204 and 0.009, respectively. There were much higher heat spell events during DJF and SON with probability occurrence of 0.78 and 0.98 at p<0.05, respectively. Precipitation extreme indices (PRCPTOT, R30 mm, RX5 day, and R95p) had a non-significant positive trend at p<0.05.