The literature oers many formulas for estimating the mean and standard deviation of a subjective probability distribution (a well-known example is the PERT formulas). This paper shows that some basic underlying assumptions behind most of these formulas are inappropriate; a more appropriate framework
A distributed approach for estimating catchment evapotranspiration: comparison of the combination equation and the complementary relationship approaches
β Scribed by Z. X. Xu; J. Y. Li
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 282 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0885-6087
- DOI
- 10.1002/hyp.1196
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
In large river basins, there may be considerable variations in both climate and land use across the region. The evapotranspiration that occurs over a basin may be drastically different from one part of the region to another. The potential influence of these variations in evapotranspiration estimated for the catchment is weakened by using a spatially based distributed hydrological model in such a study. Areal evapotranspiration is estimated by means of approaches requiring only meteorological data: the combination equation (CE) model and the complementary relationship approachβthe complementary relationship areal evapotranspiration (CRAE) and advectionβaridity (AA) models. The capability of three models to estimate the evapotranspiration of catchments with complex topography and landβuse classification is investigated, and the models are applied to two catchments with different characteristics and scales for several representative years. Daily, monthly, and annual evapotranspiration are estimated with different accuracy. The result shows that the modified CE model may underestimate the evapotranspiration in some cases. The CRAE and AA models seem to be two kinds of effective alternatives for estimating catchment evapotranspiration. Copyright Β© 2003 John Wiley & Sons, Ltd.
π SIMILAR VOLUMES