| Autor: |
Oliveira, P. T. S., Wendland, E., Nearing, M. A., Scott, R. L., Rosolem, R., Rocha, H. R. da |
| Zdroj: |
Hydrology & Earth System Sciences Discussions; 2014, Vol. 11 Issue 11, p12987-13018, 32p |
| Abstrakt: |
Deforestation of the Brazilian Cerrado region has caused major changes in hydrological processes. These changes in water balance components are still poorly understood, but are important for making land management decisions in this region. To understand pre-deforestation conditions, we determined the main components of the water balance for an undisturbed tropical woodland classified as "cerrado sensu stricto denso". We developed an empirical model to estimate actual evapotranspiration (ET) by using flux tower measurements and, vegetation conditions inferred from the enhanced vegetation index and reference evapotranspiration. Canopy interception, throughfall, stem-flow, surface runoff, and water table level were assessed from ground measurements. We used data from two Cerrado sites, "Pé de Gigante" -- PDG and "Instituto Arruda Botelho" -- IAB. Flux tower data from the PDG site collected from 2001 to 2003 was used to develop the empirical model to estimate ET. The other hydrological processes were measured at the field scale between 2011 and 2014 in the IAB site. The empirical model showed significant agreement (R² = 0.73) with observed ET at the daily scale. The average values of estimated ET at the IAB site ranged from 1.91 to 2.60mmd-1 for the dry and wet season, respectively. Canopy interception ranged from 4 to 20% and stemflow values were approximately 1% of gross precipitation. The average runoff coefficient was less than 1 %, while Cerrado deforestation has the potential to increase that amount up to 20 fold. As relatively little excess water runs off (either by surface water or groundwater) the water storage may be estimated by the difference between precipitation and evapotranspiration. Our results provide benchmark values of water balance dynamics in the undisturbed Cerrado that will be useful to evaluate past and future land cover and land use changes for this region. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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