A cobertura de nuvem e a sua influência para a variabilidade térmica do solo.

Abstract

Soil temperature can be considered one of the most important environmental elements for the development of plants. The mathematical representation is obtained from a harmonic (sinusoidal) function of time around an average value and, in particular, the main limitation is centered on the fact that it applies only to days without clouds (an idealized situation that differs from day-to-day). Cloud cover is the atmospheric phenomenon that plays a more significant role in the incidence of solar radiation at the surface and, therefore, should significantly influence the daily thermal variability of the soil. In this context, the present research aims to understand the possible relationship between those variables. The cloud cover is estimated through a proposed method and, when performing the validation, uses it to investigate the relationship with the daily thermal variability of the soil. The results indicate that the variables are inversely related and, in turn, the correlation coefficient is very expressive throughout the vertical soil profile. Thus, the cloud cover should be incorporated into the mathematical model to improve it. The incorporation is done from the mathematical restructuring and, consequently, satisfactory results were obtained for the thermal amplitude of the soil (mainly, for the deeper regions). Finally, it became possible to identify the existence of a significant soil-atmosphere relationship. Keywords: Soil