Abstract
The Land Surface Albedo (LSA) was estimated in the broader Mediterranean area, on an 8-day basis, for the period 2001–2012. MODIS (Moderate Resolution Imaging Spectroradiometer) albedo product parameters, at 1 km × 1 km spatial resolution, were used. LSA changes during the above study period were also estimated, based on annual average values. Results revealed increasing LSA trends dominating in the Levant region and decreasing in NW Africa, of the order of 3.3% and −6.6%, respectively, while mixed signs were observed in southern Europe. Three factors that can determine the LSA changes were investigated: land cover changes, rainfall changes and Aerosol Optical Thickness (AOT) spatio-temporal variability. The analysis made clear that land cover and rainfall changes affect LSA at local and regional scales, while the effect of AOT was not important. Land cover changes revealed deforestation hot spots, where LSA was increased by 13%–14%, while an increase in rainfall over many areas in NW Africa appears to have caused a corresponding decrease in LSA by over 5%. These findings highlight the importance of a global and continuous LSA monitoring at both regional and local scales, which is necessary for both climate monitoring and modeling studies.
Highlights
The Land Surface Albedo (LSA), defined as the ratio of up-welling to down-welling radiation fluxes in a given wavelength or spectral interval [1], is a highly important environmental variable, primarily due to its effects on atmospheric radiation
The Sahara desert is a typical example of such areas, due to the inability of the Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol algorithm to retrieve Aerosol Optical Thickness (AOT) over bright surfaces [25]
The statistically significant rainfall trends reported here cover only small areas in NW Africa and the Levant, while southern Europe is totally absent from this analysis, those similar findings suggest that soil moisture changes constitute an important factor of corresponding LSA trends
Summary
The Land Surface Albedo (LSA), defined as the ratio of up-welling to down-welling radiation fluxes in a given wavelength or spectral interval [1], is a highly important environmental variable, primarily due to its effects on atmospheric radiation. The albedo product of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, on board NASA’s Terra and Aqua platforms, includes parameters (described in Section 2.1) for the computation of LSA on an 8-day temporal scale and a variety of spatial scales, which range from 0.5 km 0.5 km to 5 km 5 km, respectively [10]. This data set was used here for the LSA estimation and its changes over the study area at 1 km 1 km spatial resolution.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
