Estimation of soil heat flux in a neotropical Wetland region using remote sensing techniques

Victor Hugo De Morais Danelichen,Marcelo Sacardi Biudes,Nadja Gomes Machado,Bernardo Barbosa Da Silva,José De Souza Nogueira,Maísa Caldas Souza

doi:10.1590/0102-778620120568

Abstract

The direct estimation of the soil heat flux (G) by remote sensing data is not possible. For this, several models have been proposed empirically from the relation of G measures and biophysical parameters of various types of coverage or not vegetated in different places on earth. Thus, the objective of this study was to evaluate the relation between G/Rn ratio and biophysical variables obtained by satellite sensors and evaluate the parameterization of different models to estimate G spatially in three sites with different soil cover types. The net radiation (Rn) and G were measured directly in two pastures at Miranda Farm and Experimental Farm and and Monodominant Forest of Cambará. Rn, G, and G/Rn ratio and MODIS products, such as albedo (α), surface temperature (LST), vegetation index (NDVI) and leaf area index (LAI) varied seasonally at all sites and inter-sites. The sites were different from each other by presenting different relation between measures of Rn, G and G/Rn ratio and biophysical parameters. Among the original models, the model proposed by Bastiaanssen (1995) showed the best performance with r = 0.76, d = 0.95, MAE = 5.70 W m-2 and RMSE = 33.68 W m-2. As the reparameterized models, correlation coefficients had no significant change, but the coefficient Willmott (d) increased and the MAE and RMSE had a small decrease.

Highlights

The Mato Grosso State has a rich ecological diversity in three distinct biomes (Amazon, Pantanal and Cerrado), which have special importance on global climatic changes issues (Arieira et al, 2011)
The assessment of energy exchange can be carried by micrometeorological techniques, which allows the characterization of local microclimate, as well the identification of the ecosystem function changes caused by anthropogenic activities (Biudes et al, 2009)
Remote sensing techniques are highlighted because they allow monitoring of energy exchange on a regional scale using a few ground data (Allen et al, 2011)

Summary

Introduction

The Mato Grosso State has a rich ecological diversity in three distinct biomes (Amazon, Pantanal and Cerrado), which have special importance on global climatic changes issues (Arieira et al, 2011). Recent trends of economic development have contributed to convert natural areas in pasture and cropland (Wantzen et al, 2008; Milne et al, 2010) This landscape conversion changes the energy exchange of the soil-plantatmosphere system (Coutinho, 2010). The assessment of energy exchange can be carried by micrometeorological techniques, which allows the characterization of local microclimate, as well the identification of the ecosystem function changes caused by anthropogenic activities (Biudes et al, 2009). These technics provide a punctual measure of the energy exchange and its use to spatial characterization is expensive and laboriously. Remote sensing techniques are highlighted because they allow monitoring of energy exchange on a regional scale using a few ground data (Allen et al, 2011)

Objectives

Methods

Conclusion