Satellite Measurements of Surface Albedo and Temperatures in Semi-Desert

Abstract

Measurements of surface parameters in an arid steppe (the semi-desert of the northern Sinai) were made from the NOAA-6 satellite to assess the effects of the vegetation recovery in a fenced-off area. The radiances measured in the solar wavelengths over the vegetated area were about 25% lower than those measured over the surrounding bare sandy soil (where the surface albedo measured from Landsat is about 0.42). This implies a reduction in the albedo by the vegetation also by about 25% if both surfaces are regarded as Lambertian, but by as much as 42% if the vegetated area is modeled as a plane of soil with vertically protruding plants. The radiation temperatures in the 11 μm channel at ∼0730 LST measured over the vegetated area were by as much as 2.5 K higher than over the surrounding sands. Abstract Measurements of surface parameters in an arid steppe (the semi-desert of the northern Sinai) were made from the NOAA-6 satellite to assess the effects of the vegetation recovery in a fenced-off area. The radiances measured in the solar wavelengths over the vegetated area were about 25% lower than those measured over the surrounding bare sandy soil (where the surface albedo measured from Landsat is about 0.42). This implies a reduction in the albedo by the vegetation also by about 25% if both surfaces are regarded as Lambertian, but by as much as 42% if the vegetated area is modeled as a plane of soil with vertically protruding plants. The radiation temperatures in the 11 μm channel at ∼0730 LST measured over the vegetated area were by as much as 2.5 K higher than over the surrounding sands.