Abstract
Ground based measurements which were carried out in the Northern Sahel in southern Tunisia showed the following results:
-
(a)
The albedo difference between ground and protected land is about 10%, half of the amount Charney (1975) used in his model.
-
(b)
Bare soil is always warmer during times of bright sunshine than vegetated soil, which is in agreement with Jackson and Idso (1975). Temperature differences in excess of the 10 °C were observed between plants and the surrounding soil.
-
(c)
For bare soil, the surface temperature increases with declining albedo. However the opposite holds true for plants. Here, when lowering the albedo, a decrease in temperature was found.
-
(d)
In a sand dune field, the surface temperature depends strongly on the exposure. Surface temperature differences of 8 °C were observed for slopes of different exposures for measurements carried out around noon.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Ångström, A.: 1916, ‘Über die Gegenstrahlung der Atmosphäre’,Met. Z. 33, 529–538.
Berkofsky, L.: 1976, ‘The Effect of Variable Surface Albedo on the Atmospheric Circulation in Desert Regions’,Journal of Applied Meteorology 1139–1144.
Bolz and Falckenberg, G.: 1949, ‘Neubestimmung der Konstanten der Angströmischen Strahlungs-Formel’,Z. f. Met. 3, 97–100.
Charney, J.: 1975, ‘Dynamics of Deserts and Drought in the Sahel’,Quart. J. R. Met. Soc. 101, 193- 202.
Charney, J., Stone, P. H., and Quirk, W. J.: 1975, ‘Drought in the Sahara: A Biogeophysical Feedback Mechanism’,Science 187, 434–435.
Charney, J., Stone, P. H. and Quirk, W. J.: 1976, ‘Reply to E.A. Ripley’,Science 191, 100–102.
Dirmhirn, I.: 1967,On the Applicability of Silicon Cells in Atmospheric Radiation Studies, Report for Contract NASA-NGR-06–002–038. US. Government Printing Office, Washington, D.C.
Dirmhirn, I. and Eaton, F.: 1978, ‘Airborne Infrared Measurements of Logan Canyon, Utah’,Fourth Symposium on Meteorological Observations and Instrumentation, April 10–14, Denver, Colorado, 1979.
Eaton, F. D. and Dirmhirn, I.: 1979, ‘Reflected Irradiance Indicatrices of Natural Surfaces and their Effect on Albedo’,Applied Optics 18, 994–1008.
Ellsaesser, H. W., MacCracken, M. C., Potter, G. L., and Luther, F. M.: 1976, ‘An Additional Model Test of Positive Feedback from High Desert Albedo’,Quart. J. R. Met. Soc. 102, 655–666.
Flohn, H. and Ketala, M.: 1970,Etude des Conditions Climatiques de l'avance due Desert, WMO Technical Notes, No. 116, WMO No. 279.
Flohn, H., Saharization: 1971,Natural Causes or Management? WMO - Special Environm Report No. 2 WMO No. 312, 101–106.
Flohn, H.: 1977,Climate Fluctuations in the Arid Belt of the Old World since 10 000 BP: Possible Causes and Future Implications, Conference on Meteorology of Semi-arid Areas, Tel Aviv.
Flohn, H., Henning, D., and Korff, H. Cl.: 1974, ‘Possibilities and Limitations of a Large-Scale Water Budget Modification in the Sudan-Sahel Belt of Afrika’,Meteor. Rundsch. 27, 97–100.
Flowers, E.: 1979,NOAA Calibration Center Operations. 1st DOE Environmental Resource Assessments Branch Quarterly Contractors Program Reviews.
Geiger, R.: 1975,The Climate Near the Ground, Harvard University Press. Cambridge Mass. 611.
Hare, F.: 1976,Climate and Desertification. Report Prepared for the United Nations Environment Programme. Univ. of Toronto, Inst. for Envir. Studies.
Idso, S. B.: 1977, ‘A Note on Some Recently Proposed Mechanisms of Genesis of Deserts’,Quart. J. R. Met. Soc. 103, 369–370.
Jackson, R. D. and Idso, S. B.: 1975, ‘Surface Albedo and Desertification’,Science 189, 1012–1013.
Joseph, J. H.: 1977,The Effect of a Desert Aerosol in a Model of the General Circulation (Keynote Paper), Proceedings of the Symposium on Radiation in the Atmosphere, 487–492.
List, R. J.: 1968,Smithsonian Meteorological Tables, Vol. 114, 6th Edition Smithsonian Institution Press: Washington D.C.
Novikoff, G., Wagner, F. H., and Hajjaj, M. S.: 1977,Systems Analysis of the Presaharan Ecosystem of Southern Tunisia, Desert Biome Report No. 6.
Ohring, G. and Gyoeri, S.: 1977, ‘Some Experiments with a Zonally Averaged Climate Model’,Proceedings of the Symposium on Radiation in the Atmosphere, 493–495.
Otterman, J.: 1974, ‘Baring High-Albedo Soils by Overgrazing: A Hypothesized Desertification Mechanism’,Science 186, 531–533
Otterman, J.: 1981, ‘Satellite and Field Studies of Man's Impact on the Surface in Arid Regions’,Tellus 33, 68–77.
Otterman, J. and Tucker, C. J.: 1982, ‘Satellite Monitoring of Surface Temperatures in Semi-Desert: Differences between Anthropogenically Impacted Terrain and Protected Natural Vegetation’, (draft) Invited Paper 10.2.6.Advances in Space Research.
Rasool, S. I., Courel, M. F., Kandel, R., and Habif, M.: 1982, ‘Satellite Investigations of Surface Cover Changes in Sahel during the Last Decade’,Proceedings of COSPAR, Ottawa.
Ripley, E. A.: 1976, ‘Drought in the Sahara: Insufficient Biogeophysical Feedback?’Science 191, 100.
Walker, J. M. and Rowntree, P. R.: 1977, ‘The Effect of Soil Moisture on Circulation and Rainfall in a Tropical Model’,Quart. J. R. Met. Soc. 103, 29–46.
Wendler, G. and Streten, N. A.: 1969, ‘A Short Term Heat Balance Study on a Coast Range Glacier’,Pure and Applied Geophysics 77, 68–77.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wendler, G., Eaton, F. On the desertification of the Sahel zone. Climatic Change 5, 365–380 (1983). https://doi.org/10.1007/BF02423531
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02423531