12. What type of maps on drought and desertification exist?

Knowledge of drought and desertification (impacts of climate change) has greatly increased over the last few years, as space-time synoptic images produced by various satellites since the 1990s have enabled specialists to draw up reports on the progression of drought and desertification, locating and delimiting the affected areas by producing a series of thematic maps. It is therefore essential to systematically collect data and make observations about natural resources and their uses so as to better understand the processes of soil impoverishment, drought and desertification and to evaluate their effects. These data are also necessary in order to quickly alert decision makers to the problem. This will help them to evaluate the benefits of local ecosystems in a realistic way and allow them to establish appropriate development and conservation policies. Creating risk awareness maps and updating them regularly can also increase investment in improved land planning and development and justify investments in sustainable means of subsistence.

Go to 12.1 More information on remote sensing applied to drought and desertification mapping

Go to 12.2 References

Remote sensing: a tool for monitoring.

Several researches were launched in this objective of monitoring, follow-up and cartography of drought, desertification and climatic changes impact in countries affected by these plagues.

Figure -15- Wind lane Map and the risk of silting in West region of Biskra CRSTRA (Algeria)


Research carried out in the Algerian steppe, the Tunisian South (Menzel Habib) in sub-Saharan countries (Niger) and on the desert fringe of the Nile clearly proved the feasibility of the follow-up of desertification by satellite. Time to confront resultants with the reality of the ground and necessity of the spacial imaging


Indicators of the drought and desertification state (color and composition of soils, roughness, deposit rates of vegetation) and of its evolution, could be obtained since space by remote sensing. Maps can be elaborated from these indices whose crossings in a GIS give the state of environment to a T time.

Expander cards of mobile sands and the biomass degradation were established by remote sensing by image processing and of indices such as the vegetation index, color and brightness of surfaces recorded by images are calculated.

The remote sensing techniques, combined with a very good knowledge of soil, allow detecting the evolution of degradation of arid regions but also their restoration.

Considering these risks exceed the limits of countries even continents, programs such as the Cameleo program (). The IRD led, in collaboration with the Egeo unit of Institute of space applications of the Joint Research Center and with the support of the European Union, This research, which associates Algeria, Egypt, Morocco and Tunisia, and is based on the Roselt network; aim at defining a complete method of follow-up of desertification in the south of the Mediterranean.
It is in particular a question of obtaining, on field and by satellite remote sensing, data usable for management of the arid environment and similar from a country to another. This in order to identify, at a local scale, zones where soils and vegetation are degraded, are stable or to be improved, and to understand relations between these changes and their use by the man.

In Algeria, map of sensibility in the desertification was elaborated in 1995 by the FGD and the ALSA. It is perpetually actualisable.Therefor,the Center of Scientific and Technical Reasearch on Arid Regions (CRSTRA),elaborated vulnerability maps on desertification and silting through ecological entities.
Besides, the OSS, the HAD and the partners of the Magreb (ALGERIA TUNISIA MOROCCO) work at the implementation of the early alarm system through the Life SMAS project, this alert focuses on the production and the distribution of indicators of vulnerability of naturalresources, compared to the climatic and anthropological press to which they are subjected. The elaboration of indicators has to use all the available approaches, climatic satellital embellish with images, in the compilations of the meteorological, dated, the biophysics and socioeconomic. The indicators of premature alert of the drought will feed also information flow systems of the national and sub-regional action plans to combat desertification, established in accordance with principles of the Convention of the United Nations to Combat Desertification.

To evaluate the progression of these insidious phenomena (drought, desertification and climate changes impacts), the remote sensing helps collecting data on vast surfaces with regular intervals. By comparing data images between dates, it is probable to find out the evolution of drought and desertification.

Maps can be established such as the albedo (R0), the vegetation index (NDVI) and the temperature of surface Ts recorded thanks satellite measurements of sensor MODIS of TERRA or VEGETATION of SPOT or by sensors AVHRR of NOAA these satellites which provide images to weak space resolution and allow carrying out a regular follow-up at very weak cost of natural resources.

These images have a broad observation field (about entire country) and a daily temporal resolution, very useful for a regular follow-up, mainly the vegetation.

Furthermore, to make a note of the use of images with average resolution such as Land sat, (30m of resolution space) Alsat (32m), SPOT (20m) and images with high resolution such as IKONOS (1m) Quicbird (1m).

For characterization and cartography of the hydric state, the soil quality and state of degradation of a surface. One of the key ideas is the combination of these parameters resulting by image processing two to two (R0 – Ts; NDVI – Ts and R0 – NDVI).

The quoted images may be provided by manufacturers of these satellites as they may be ordered by representatives of these structures in several countries. Each image includes its price (see site SPOTIMAGE). Concerning the factorial maps, grounds, of the ground occupation, drought, desertification; May be that they are public and setting on line on Internet as it is the case of several countries, are requested from the manufacturer.

  1. AIDOUD A.,2009, Trente années d’observations de la steppe (Algérie Atelier international sur les Risque Majeurs et les Catastrophes Naturelles, CRSTRA (15.H6/17decembre 2010).
  2. ANDIEU et al, 1997, « In le Houérou .H.N 2002 « Multipurpose germplasm of fodder shrubs and trees for the rehabilitation of arid and semi arid land in the Mediterranean isoclimatic zone » A photographic catalogue/Options Méditerranéenes/Etudes et recherches N° 37/CIHEAM. 
  3. AUBREVILLE A.,1949 Climats, Forêts et désertification de l’Afrique tropicale, Société d’éditions géographiques, maritimes et coloniales, Paris, 1949,(351 p). 
  4. BEDRANI, BESSAOUD, 2006, in Nedjraoui Dalila et Bédrani Slimane.La désertification dans les steppes Algériennes : causes, impacts et actions de lutte. Vertigo .(volume 8 N° 1 Avril 2008).
  5. DAUPHINÉ A.-2003 Risques et Catastrophes, Observer, Spatialiser Comprendre, Gérer ; ed ; ARMAND COLIN ; 288 p.  
  6. DAVID E. ALEXANDER and Rhodes W Fairbridge, The Encyclopedia of Environmental Science (741 p). 
  7. DIOMBERE, Kaoussou (2000), Mitigating the effects of drought in Guinea-Bissau/Researcher, inforestry Economic and Policy, Generz.Direction of forests and Huntig (DGFC/MAFC)Guinea-Bissav.97-102 .Combating Desertification ,Proceedings of the N’Djemena CHAD. International Seminar, Novembre 2000. 
  8. DORIZE L., 1990,La sécheresse: en quête d’une définition… Revue Sécheresse (volume 1, N°1 Mars 1990 )
  9. DRAIN .M, 2006, «  Entre logique d’entreprise et logique citoyenne. A propos d’un projet de transfert d’eau. International ». Les Conférences-Rencontres de Luminy 14 Mai 2006 
  10. DUNGLAS j. 1993, Effet de serre et activités humaines (gaz à effet de serre d’origine anthropique). 
  11. GOUDRIAAN .J, 1992, «Le Réchauffement et la végétation page 606 – 609 » l’a revu N° 243-N° Spécial- l’Effet de serre. 
  12. KARA M.2000, la menace climatique, édition DAHLEB.
  13. OPTIONS MÉDITERRANÉENNES, série B : Etudes et recherches Numéro 37, édition CIHEAM. 
  14. LAKHDARI F. 2009, Desertification ; a threat for both sides of the Mediterranean/ European and Mediterranean workshop, climate change impact on water –related and marine risks 26-27 October 2009.Murcia, Spain. 
  15. LAMBERT G .1992, Les gaz à effet de serre, recherche N° Spécial Mai p-550-556. 
  16. LE HOUEROU, 1979, La désertification des régions arides, revue la Recherche N° 99 avril 1979, volume 10 (p336-344). 
  17. LEFÉVRE .C & Schneider, 2003, Les risques naturels majeurs, collection géosciences.
  18. MARGAT J. 1990, L’Économie de l’eau dans le Monde, ressources, besoins, problèmes (p 277-289) in , le grand livre de l’eau , éd. La manufacture et la cité des sciences et de l’industrie.
  19. MATARI A. 2007, Analyse de longues séries en vue du changement climatique /Actes des journées internationales sur l’impact des changements climatiques sur les régions arides et semi arides (p15-25) Biskra, Algérie 15 et 17 décembre.
  20. RAMADE F. 2002, Dictionnaire Encéclopedique de l’Ecologie et des Sciences de l’Environnement, (1076 p) .
  21. SALAMANI M. et HIRCHE A. ; «  L’état de la désertification en Algérie. Actes des journées internationales sur la désertification et le développement durable, CRSTRA- Biskra, Algérie.2006 ».
  22. SIRCOULON J, 1992 Impact sur les ressources en eau de quinze années de sécheresse au sahel ORSTOM. Ford documentaire 33.796 ex1 cote