On the desertification of the Sahel zone - Part 1: Ground observations

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. © 1983 D. Reidel Publishing Company.