Abstract
The semi-arid Sahel zone of Africa has suffered several periods of severe drought since about 1950. We have analyzed AVHRR Normalized Difference Vegetation Index (NDVI) over the Sahel for the period 1982-2002, and found extensive areas of increasing NDVI. To verify these changes we have analyzed Landsat TM and ETM+ scenes from 1984-1986 and 1999-2001 for areas in the Sudan, Central African Republic, Niger, Mali and Mauritania. Changes in the Landsat data were analysed by visual interpretation and change vector analysis. In areas of positive AVHRR NDVI change the analysis of Landsat data generally showed a transition from barren or sparse vegetation to a denser vegetation cover. Rainfall had increased over the course of time in several of these areas. In some areas visual interpretation indicated an expansion of agricultural land.
| Original language | English |
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| Publication status | Published - 2005 Dec 1 |
| Event | 31st International Symposium on Remote Sensing of Environment, ISRSE 2005: Global Monitoring for Sustainability and Security - St. Petersburg, Russian Federation Duration: 2005 Jun 20 → 2005 Jun 24 |
Conference
| Conference | 31st International Symposium on Remote Sensing of Environment, ISRSE 2005: Global Monitoring for Sustainability and Security |
|---|---|
| Country/Territory | Russian Federation |
| City | St. Petersburg |
| Period | 2005/06/20 → 2005/06/24 |
Subject classification (UKÄ)
- Physical Geography
Free keywords
- Africa
- Change vector analysis
- Landsat
- NOAA NDVI
- Sahel
- Vegetation change
