Environmental control on water vapour and energy exchanges over grasslands in semiarid region of Brazil

Revista Brasileira de Engenharia Agrícola e Ambiental

Lima, José R. de S.³  Hammecker, Claude²  Antonino, Antonio C. D.¹  Gomes, Clarissa A.³  Silva, Renan A. B. da³  Gondim, Patrícia S. de S.³ 

[1] UFPE, Recife;IRD, Montpellier, France;UFRPE, Garanhuns

关键词: evapotranspiration;    soil water content;    leaf area index;   

DOI  :  10.1590/1807-1929/agriambi.v19n1p3-8

学科分类：农业科学（综合）

来源: Universidade Federal de Campina Grande * Centro de Ciencias e Tecnologia

【 摘 要 】

A micrometeorological experiment was conducted over grasslands in a semi-arid region of north-eastern Brazil (São João, Pernambuco) from January to December 2011, using the Bowen ratio energy balance method, to improve the current understanding of energy partitioning and water vapour exchange over this ecosystem in this region. The objectives of the present study were to quantify the seasonal and diurnal variations in energy and water vapour exchanges over grasslands and understand the biotic and abiotic factors controlling the energy partitioning of this ecosystem. In the dry period, the low stored soil water limited the grass production and leaf area index, and as a consequence of these conditions, most of the annual net radiation (58%) was consumed in sensible heat flux. During the course of the study the evaporative fraction was linearly related to the leaf area index. The total annual evapotranspiration and its daily maximum were 543.8 mm and 3.14 mm d-1. The seasonal and diurnal variations in energy partitioning and evapotranspiration were controlled by soil water availability and leaf area index.

【 授权许可】

Unknown