TITLE:
Temporal and Spatial Variation Characteristics of March-April-May Precipitation in Tanzania and Its Relationship with SST
AUTHORS:
Mnana Twaha, Daniel Semgomba, Daudi Ndabagenga, Mustafa Mwinjuma
KEYWORDS:
March-April-May (MAM) Rainfall, El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Pacific Decadal Oscillation (PDO)
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.13 No.12,
December
5,
2025
ABSTRACT: This study examines the temporal and spatial variation characteristics of March-April-May (MAM) rainfall over Tanzania and its relationship with Sea Surface Temperature (SST) anomalies using data from 1981-2024. Results reveal a strong north-south rainfall gradient, with enhanced precipitation over the northern, coastal, and Lake Victoria regions, influenced by the Intertropical Convergence Zone (ITCZ), Indian Ocean moisture transport, and local topography. Trend analysis indicates an overall increasing pattern of MAM rainfall, particularly in the southern highlands, central plateau, and coastal areas, while localized declines appear in the Lake Victoria Basin. The Empirical Orthogonal Function (EOF) analysis identifies three dominant modes explaining about 61% of the total rainfall variance, representing widespread, dipole, and zonal variability patterns. Composite circulation analysis shows that wet MAM years are associated with strong low-level moisture convergence, upper-level divergence, and enhanced vertical motion, while dry years display subsidence and reduced moisture inflow. Additionally, global SST anomalies—notably from the Central Pacific ENSO, Western Indian Ocean Dipole (IOD), and Northern Pacific variability—exert significant teleconnection influences on Tanzania’s MAM rainfall. Overall, the findings highlight that Tanzania’s MAM rainfall variability is strongly modulated by SST anomalies and atmospheric circulation systems, providing a scientific foundation for seasonal forecasting, water management, agriculture, and climate adaptation strategies.