Faculty of Engineering

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Browsing Faculty of Engineering by Author "Acayo Grace"

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    Analyses of multi-decadal variability and trends in precipitation and potential evapo-transpiration across lake Kyoga basin
    (Kyambogo University, 2020-10) Acayo Grace
    The Lake Kyoga basin is located in Kyoga water management zone covering eleven sub-catchments in Uganda. The population in this region mainly depend on rain fed agriculture for their livelihood. However, recent changes in precipitation and climatic conditions calls understanding trends and variability of current and historical hydro-climatic variables. This study analyzed long-term trends and variability in precipitation and Potential Evapo-Transpiration (PETo) covering the period 1901 -1960 and 1961- 2015 respectively. Two periods were considered to remove the effect of step-jump in precipitation mean on analyses. For PETo, the period 1961-2008 was considered. Both trends and variability were assessed non-parametrically using the cumulative sum of rank difference approach. Possible drivers of variability in PETo and precipitation were sought in terms of the co-variation of the climatic variables with the large scale ocean-atmospheric interactions. The correlation of precipitation, potential Evapo-transpiration and climate indices were assessed. The climate indices included Atlantic Multi-Decadal Oscillation (AMO), North Atlantic Ocean (NAO), Indian Ocean Dipole (IOD) and Nino3. It was found that precipitation over the period 1901-1960 for the month of March, April, May (MAM) exhibited positive anomalies was not significant (p>0.05) implying wet condition, however, for September, October, November (SON) and annual time series exhibited negative anomalies. The annual variability in precipitation yielded negative anomalies around 1960s to 1970s while positive anomalies were exhibited around 1990s and 2000. Variability in annual precipitation at most locations was found to be insignificant (p>0.05). Trends in PETo were not coherent as those of precipitation.