Approximating the average daily surface albedo with respect to soil roughness and latitude

Abstract

The present study explores the diurnal variations in blue-sky albedo (α) of soils under clear sky conditions with respect to surface roughness. Three roughness levels of ploughed and unploughed soil surfaces, developed from the same loessial material, were examined. The relation between α of the surfaces and the solar zenith angle, determined during the experiment, enabled us to predict the diurnal α variation of the surfaces throughout the year at a given latitude, between 75° S and 75° N. The optimal time (T _O) for measuring the soil albedo by an instantaneous observation was considered as the best represented time for the daily averaged value within an error lower than ±2%. It was found that the T _O, falling at different times depending on the soil surface roughness, limits the possibilities of data achievement by remote-sensing satellites along one of their sun-synchronous orbits.

Acknowledgements

This work was carried out within the framework of the projects 2 P04E 030 29 and NN 306013637, supported by the Polish Ministry of Science and Higher Education and by the ‘Sixth EU Framework Programme – Transnational Access implemented as Specific Support Action – Dryland Research’ (EC contract number 026064).