Contribution to collective works (Parts of books)
Ongoing desertification processes in the sahelian belt of West Africa: An evidence from the rain-use efficiency.
Hountondji, Yvon-Carmen; Sokpon, Nestor; Nicolas, Jacques et al.
2009In Röder, Achim; Hill, Joachim (Eds.) Recent Advances in Remote Sensing and Geoinformation Processing for Land Degradation Assessment
 

Files


Full Text
Hountondji_et_al__2009-ISPRS__chap-livre_.pdf
Publisher postprint (17.5 MB)
Download

All documents in ORBi are protected by a user license.

Send to



Details



Keywords :
Desertification; Remote Sensing; Rain Use Efficiency; Rainfall; NDVI; Sahel
Abstract :
[en] The implementation of the UNCCD needs the identification of areas that record declining productivity of the vegetation over long-time periods. In this scope, we analyze the state of the vegetation productivity using 1982–1999 time series of NOAA-AVHRR NDVI data and compare it to rainfall data. For this, 354 rain gauges data distributed from yearly average isohyets 100 to 900 mm in five countries of West Africa are analyzed. We use for trends analysis, the ratio between integrated vegetation index (iNDVI) during the growing period (June to October) and the May to October sum of rainfall (RR). This ratio is a proxy of the Rain Use Efficiency is the widely accepted. Overall, 91% and 94% of RR and iNDVI data recorded positive trends over the 1982–1999 periods. Most stations in the Sahel were stable for the iNDVI/RR (49.5%). However, 37.8% showed strong to very strong negative change in the iNDVI/RR ratio, while only 1.3% showed positive trend. These strong negative trends recorded in more than 1/3 of the analyzed stations may reflect ongoing desertification processes in the Sahel and could be a starting point for the identification of hot-spots areas to determine where to take action within the National Action Programs (NAP) or Sub-Regional Action Programs (SRAP) to combat desertification.
Disciplines :
Environmental sciences & ecology
Earth sciences & physical geography
Author, co-author :
Hountondji, Yvon-Carmen ;  Université de Liège - ULiège > Sciences agronomiques > Laboratoire de Toxicologie environnementale
Sokpon, Nestor
Nicolas, Jacques ;  Université de Liège - ULiège > Département des sciences et gestion de l'environnement > Surveillance de l'environnement
Ozer, Pierre ;  Université de Liège - ULiège > Département des sciences et gestion de l'environnement > Département des sciences et gestion de l'environnement
Language :
English
Title :
Ongoing desertification processes in the sahelian belt of West Africa: An evidence from the rain-use efficiency.
Publication date :
2009
Main work title :
Recent Advances in Remote Sensing and Geoinformation Processing for Land Degradation Assessment
Editor :
Röder, Achim
Hill, Joachim
Publisher :
Taylor & Francis Group, London, United Kingdom
ISBN/EAN :
978-0-415-39769-8
Collection name :
International Society for Photogrammetry and Remote Sensing (ISPRS) Book Series, n°8
Pages :
173-186
Available on ORBi :
since 01 December 2010

Statistics


Number of views
200 (8 by ULiège)
Number of downloads
789 (7 by ULiège)

Bibliography


Similar publications



Contact ORBi