Analysis of the influence of tropical cyclones on mam rainfall season over Uganda
Abstract
ABSTRACT
Tropical Cyclones(TCs) are frequently associated with disasters given the adverse impacts that the related
intense winds, storm surges, and heavy rainfall have on vulnerable regions and yet given less attention for
our region, thus the study’s main objective is to analyze the influence of Tropical cyclones on March,
April, May rainfall over Uganda. with the specific objectives to determine the trend in the March, April,
May seasonal rainfall over Uganda, to establish the trend in the frequency of tropical cyclone occurrence,
and to determine the relationship between tropical cyclones occurrence and the March, April, May season
rainfall totals over Uganda for the period (2000 to 2019). The datasets used in this study included
reanalyzed monthly rainfall data, for ten meteorological stations (Arua, Tororo, Gulu, Kasese, Soroti,
Jinja, Kasese, Masindi, Mbarara, and Entebbe), u and v components of wind at 850hPa for the entire
globe obtained from ERA5 data, Tropical cyclone best track data extracted from joint typhoon warning
center for the period 2000-2019. The study employed trend analysis, linear correlation, and graphical
method. Generally, trend analysis depicted an increasing trend in MAM rainfall in most of the stations
and a decreasing trend in the frequency of Tropical cyclones. However, these results shows that the
rainfall trends at nine out of the ten stations and the trend of occurance of TCs are not statistically
significant with (P>0.05) and only Entebbe station being significant with(p<0.05). Results for the linear
correlation between tropical cyclone occurrence and rainfall depicted a weak Negative linear relationship
throughout all the stations except for Kasese, Tororo, and Mbarara which showed a positive linear
relationship of 0.1303, 0.011 and 0.01 respectively but not statistically signifigant.