Spatial variability of the English agricultural landscape and its effect on evaporation

The variability of leaf area index, canopy height and albedo is measured across an agricultural landscape in lowland Britain. The dependency of the variability with spatial sampling is quantified and the sensitivity of modelled evaporation to the variability is assessed. From this study, it appears that the leaf area index can display significant variability between fields of growing crops as their plant and harvest times may differ by the order of a month. In addition the albedo variability is high. Both these quantities have an influence on the resulting evaporation (between 1% and 40% depending on assumptions) and need to be accounted for. Although the crop height varies considerably, it does not have a big impact on evaporation (less than 4%).