Drought Assessment with the Context of Climatic Variation using GIS and Remote Sensing: Case of Dodoma Region

Abstract

This study involves assessment of areas that are prone to drought focusing on specific climatic indicators and using GIS and Remote Sensing techniques. While several previous studies have been describing drought conditions in semiarid areas by incorporating precipitation deficit and poor rainfall distribution, this research focused on precipitation, temperature and vegetation cover to quantify the drought phenomena using spatial methods.

Satellite images and meteorological data were used. A quantitative assessment of the drought was conducted using the Mann-Kendall model, NDVI, and Standardized Precipitation Index (SPI). Subsequently, the LANDSAT images and Netcdf data were used to calculate the NDVI for showing the vegetation health for particular year and the calculations were performed to get the annual average temperature and precipitation for each year. Rainfall data from meteorological stations were then used to calculate SPI values.

The study revealed significant spatial and temporal variations in temperature and precipitation across Dodoma. The time series of climatic changes for rainfall ranged from 740 to 927 mm and for the temperature ranged from 25˚c to 31˚c for the year 2000 to 2021. The spatial distribution of vegetation health from 2000 to 2021 was from medium to low vegetation. Most of the SPI values in the plot are negative, which shows a uniform trend of below-average precipitation over the course of the period. The graph demonstrates notable negative spikes that occurred in 2001, 2002, 2013, 2014, 2018, and 2020 with levels considerably below -2. SPI readings below -2 typically denote severe or extreme drought conditions.

Understanding how climate change affects the future drought of an area is important for planning suitable adaptation and mitigation actions to manage drought risk. Further studies are recommended to focus on long-term drought mitigation methods to minimize drought risk while considering various drought management strategies.