Evaporation from natural mountain grassland
Wright, I.R. | Harding, R.J.
Evaporation from upland grassland is investigated using the results from two weighing lysimeters. The lysimeters were operated at a site on the Balquhidder catchments at an altitude of 595 m for 2 years (1988 and 1989). The results show an evaporation rate which is significantly below that of the Penman evaporation E(T), particularly in the early part of the year, when the grass is dormant. The lysimeter data have been used to calibrate and assess a number of water use models designed to estimate grassland evaporation from meteorological measurements. Transpiration models to take account of the dormancy of the vegetation were tested using either a temperature function or a seasonally adjusted crop factor. The introduction of a simple interception model did not improve the model fit. A range of models gave a very good fit to the cumulative total evaporation; the most generally applicable model reduces the evaporation at low air temperatures.Show more [+] Less [-]