Mbululo, Yassin Adam2025-04-142025-04-142012https://www.suaire.sua.ac.tz/handle/123456789/6660DissertationThis study was conducted to examine the climate characteristic of southern highland Tanzania (Latitude 6°S-12°S and Longitude 29°E-38°E). In order to meet the objectives of this study, monthly average rainfall data from Tanzania Meteorological Agency (TMA) and global marine environmental data, which consists gridded monthly sea surface temperature (SST), sea level pressure (SLP) and zonal (U) and meridional (V) wind components from National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory were used. The rainfall data was used to develop Standardized Precipitation Index (SPI) which was then used to find correlation with global marine environmental parameters. Wavelet method was used to analyze variations of power within the time series and dominant modes of rainfall variability The study findings revealed that rainfall over the region is linked with SST over the Indian Ocean, where warmer (cooler) western Indian Ocean is accompanied by high (low) amount of rainfall over Tanzania. During wet (dry) years, weaker (stronger) equatorial westerlies and anticyclone (cyclonic) anomaly over the southern tropics act to reduce (enhance) the export of equatorial moisture away from East Africa. Not only that, but also moisture influx from the northeast Indian monsoon has significant influence on the rainfall over the region. During the wet years, strong northeasterly Indian monsoon is evident over most of Tanzania while during the dry year the northeasterly is seen to turn north hence denying moisture influx over Tanzania. In addition, increased (decreased) low level moisture influx from gulf of Guinea and Congo basin tend to occur during the wet (dry) seasons, leading to enhanced (reduced) low level moisture convergence over western part of Tanzania. Results suggest the wettest season in record to be 1978/79 which can be classified as the “Severely wet” and the driest season in record to be 1999/00 which can be classified as “Moderate drought”. Different dominant periodicity modes have been observed over the study period, but two of them seem to be more dominant over the whole study period. These modes of rainfall have been identified at time scale of 2 and 7 years which may be associated with the quasi biennial oscillation (QBO) and El Nino Southern Oscillation (ENSO) respectively. Moreover, key areas over the Ocean have been identified to be in between 5°S-18°S and 58°E-70°E for Indian Ocean and 2°N-17°S, 5°W-IO°E for Atlantic Ocean. The study recommends a closer follow-up on the local variation of SST over these key areas as they can help in forecasting year to year rainfall variability. Also responsible institutions in the government should make use of the findings from this study as a benchmark in improving agriculture sector and vigilance for extreme events.enTanzaniaClimate characteristicsDominant periodicity modeThesis