Evapotranspiration of the Brazilian Pampa Biome: Seasonality and Influential Factors

Gisele Rubert,Luis Pereira,Haroldo Campos Velho,Fernando Quadros,Débora Roberti,Osvaldo Leal De Moraes

doi:10.3390/w10121864

Abstract

Experimentally characterizing evapotranspiration (ET) in different biomes around the world is an issue of interest for different areas of science. ET in natural areas of the Brazilian Pampa biome has still not been assessed. In this study, the actual ET (ETact) obtained from eddy covariance measurements over two sites of the Pampa biome was analyzed. The objective was to evaluate the energy partition and seasonal variability of the actual ET of the Pampa biome. Results showed that the latent heat flux was the dominant component in available energy in both the autumn–winter (AW) and spring–summer (SS) periods. Evapotranspiration of the Pampa biome showed strong seasonality, with highest ET rates in the SS period. During the study period, approximately 65% of the net radiation was used for the evapotranspiration process in the Pampa biome. The annual mean ET rate was 2.45 mm d−1. ET did not show to vary significantly between sites, with daily values very similar in both sites. The water availability in the Pampa biome was not a limiting factor for ET, which resulted in a small difference between the reference ET and the actual ET. These results are helpful in achieving a better understanding of the temporal pattern of ET in relation to the landscape of the Pampa biome and its meteorological, soil, and vegetation characteristics.

Highlights

Many experimental studies have been carried out to quantify the evapotranspiration (ET) of different ecosystems and biomes around the world using the eddy covariance (EC) methodology, which is main methodology employed to estimate actual ET from site micrometeorological measurements [1,2]
These results suggest that ETo was a good indicator of ETact in the Pampa biome because soil water soil water availability did not restrict ETact, the values of which were close to ETo
The evapotranspiration over the Brazilian Pampa biome was assessed at two sites where observations were performed using eddy covariance

Summary

Introduction

Many experimental studies have been carried out to quantify the evapotranspiration (ET) of different ecosystems and biomes around the world using the eddy covariance (EC) methodology, which is main methodology employed to estimate actual ET from site micrometeorological measurements [1,2]. The Pampa biome, characteristic of southern Brazil and part of Argentina and Uruguay, is still not well characterized using that methodology or the quantification of ET and its relationship with environmental variables. In southern Brazil, the Pampa biome presents mostly grassland vegetation interspersed with gallery forests [3]. It is a complex biome, which has different. Water 2018, 10, 1864 vegetation, among which the most representative is fields dominated by grasses. Related studies are lacking and the only recent one refers to characterizing the actual ET of Tifton 85 Bermudagrass as affected by the frequency of cuttings [4].

Methods

Results

Conclusion