African Journal of
Environmental Science and Technology

  • Abbreviation: Afr. J. Environ. Sci. Technol.
  • Language: English
  • ISSN: 1996-0786
  • DOI: 10.5897/AJEST
  • Start Year: 2007
  • Published Articles: 1070

Full Length Research Paper

A comparative analysis of MODIS-derived drought indices for Northern and Central Namibia

Wyss Daniel
  • Wyss Daniel
  • Department of Cartography, Faculty of Geoscience and Geography, GIS and Remote Sensing, Georg-August-Universitat Gottingen (GAU), Germany.
  • Google Scholar
Negussie Kaleb
  • Negussie Kaleb
  • Department of Geo-Spatial Sciences and Technology, Faculty of Natural Resources and Spatial Sciences, Namibia University of Science and Technology (NUST), Namibia.
  • Google Scholar
Staacke Antonia
  • Staacke Antonia
  • Department of Cartography, Faculty of Geoscience and Geography, GIS and Remote Sensing, Georg-August-Universitat Gottingen (GAU), Germany.
  • Google Scholar
Karnagel Amadé
  • Karnagel Amadé
  • Department of Cartography, Faculty of Geoscience and Geography, GIS and Remote Sensing, Georg-August-Universitat Gottingen (GAU), Germany.
  • Google Scholar
Engelhardt Malin
  • Engelhardt Malin
  • Department of Cartography, Faculty of Geoscience and Geography, GIS and Remote Sensing, Georg-August-Universitat Gottingen (GAU), Germany.
  • Google Scholar
Kappas Martin
  • Kappas Martin
  • Department of Cartography, Faculty of Geoscience and Geography, GIS and Remote Sensing, Georg-August-Universitat Gottingen (GAU), Germany.
  • Google Scholar


  •  Received: 01 February 2022
  •  Accepted: 04 May 2022
  •  Published: 31 May 2022

Abstract

Namibia is a semi-arid country with erratic and unpredictable rainfall. Extreme weather patterns, such as floods and extensive droughts, have become more common in recent years, with strong impact on surface and ground water availability, rangeland and agricultural productivity, food security, and further land degradation, such as bush encroachment or soil erosion. The previous 10 years were characterized by a perennial drought that lasted from 2013 to 2016 and an extreme drought that occurred during the rainy season of 2018/2019, which was the driest in 90 years. In January 2021, however, rainfall totals doubled to tripled the norm. The paper compares five drought indices in order to identify, visualize, monitor, and better understand the nature, characteristics, and spatial-temporal patterns of drought in northern and central Namibia. Based on their sensitivity to vegetation greenness, land surface temperature, evapotranspiration, and precipitation, the indices allow for calculation, time series analysis, and cross-comparison. Droughts occur every year, but the intensity of the drought varies depending on the index type.  It is concluded that a comparative analysis of multiple indices provides a better interpretation of drought than single parameter systems. Future research should include biophysical properties such as soil characteristics, soil moisture, and hydrology, as well as socioeconomic studies, in order to develop an integrated drought index for northern Namibia.

 

Key words: Remote sensing, moderate resolution imaging spectroradiometer (MODIS), drought indices, time series analysis, climate reanalysis, Namibia.