Annual Dynamics of Shortwave Radiation as Consequence of Smoothing of Previously Plowed and Harrowed Soils in Poland

Abstract

moothing a rough, deeply plowed soil increases its albedo, which determines a lower amount of shortwave radiation absorbed by its surface layer. That surface emits less longwave radiation, leading to a reduction in its temperature, which in turn can affect the climate, influencing the energy transfer between soil, vegetation, and the atmosphere. This paper presents a multistage procedure for estimating the annual dynamics of shortwave radiation reflected from bare soils as a consequence of smoothing the previously plowed and disk-harrowed fields in Poland. This procedure takes into account the spatial diversity of soil units and their properties within bare soil surfaces (extracted from Landsat 8 images), analyzed using digital maps of land use and soils as well as soil datasets stored in soil databases. One minimum and two peaks were found in the annual distribution of the radiation amount reflected from the soils only when smoothing the data. Expressing this reflected radiation as a fraction of the daily energy reaching the studied areas with clear-skies, it was predicted that those spring and summer peaks can reach about 2.2%?2.3% and 1%, respectively, of the incident shortwave radiation for soils that had been plowed and disk harrowed.