Kombo Hamad Kai
University of Dar es Salam, Tanzania
Title: The relationship between tropical cyclones and the plant productivity indices along the coast of Tanzania
Biography
Biography: Kombo Hamad Kai
Abstract
The relationship between tropical cyclone (TCs) and the plant productivity indices along the coast of Tanzania was investigated using both field observations and change detection methods. The satellite data comprising of 16 days MODIS 250 x 250 m and 8 days Landsat 7 ETM 30 x 30 m (2000-2014) and 5 Landsat 8 (LC8) images, were used to determine the pattern of the inter-annual variability of the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) and the TCs impacts on vegetation. Tropical Rainfall Measuring Mission (TRMM) acquired from TRMM website and daily to monthly rainfall data, acquired from Tanzanian Meteorological Agency (TMA) were used. Inter annual variability of NDVI/EVI over Chwaka, Rufi and Pugu- Kazimzumbwi, and monthly rainfall at the coastal stations were analyzed. The reults revealed that, 2002 had highest NDVI/EVI values, which were peaked in March and April and minimum values in November. MODIS data for most stations and TCs gave significantly lower EVI changes ranging from 0.05-0.45 (Gafilo), -0.15-0.25 (Kalunde), 0.1-0.25 (Fobane) compared to L7 ETM data where the EVI change ranged from -0.4-0.15 (Gafilo), 0.0-0.25 (Kalunde) and 0.05-0.5 (Fobane). Analyses of spatial changes in NDVI showed that TCs Besija and Fobane were associated with both decline and enhancement of the NDVI over Chwaka and Rufiji. Over Chwaka, these TCs were associated with the NDVI enhancement of > 0.51 and > 0.47 and a decline of < 0.03 and < 0.02, respectively. Over Rufiji TCs event resulted into NDVI enhancement of > 0.31 and a decline of < -0.19. Further image analyses indicated a high deposition of sediments along the shorelines, where water covered areas had changed to vegetation covered. These results were consistent with the patterns shown by analysis of rainfall data which indicated low rainfall occurred in low EVI/NDVI areas and vice versa.