Evapotranspiration Across Land Use Types: A Micrometeorological Approach to Water Balance Closure

Evapotranspiration monitoring provides essential information for weather prediction, for instance, through sensible heat flux, and for water management, particularly in regions where land use is a critical factor. Given the increasing impacts of drought and the challenges associated with monitoring, detailed ET measurements are vital for explaining meteorological and hydrological extremes from a management perspective. This study focuses on micrometeorological measurements of ET across different land use types to address key challenges in water balance estimation.

We analysed data from multiple LI-COR 710 eddy-covariance systems in agricultural and forested areas in the Netherlands to help close the gap between incoming and outgoing water fluxes in terrestrial environments. Our results reveal that the influence of ET on the water balance varies significantly within the same catchment area, depending on land use. From a hydrological perspective, these differences have important implications for policy development and management strategies, particularly under conditions of climate extremes. From an atmospheric perspective, as evapotranspiration is the primary link between the hydrological cycle and the surface energy balance, these differences suggest shifts in how net radiation is partitioned into latent and sensible heat fluxes.

This is particularly relevant due to increasing droughts in the Netherlands during the last decades. Our findings highlight the critical role of evapotranspiration in the soil–water–atmosphere continuum and highlight how land use adjust the balance between surface cooling through evaporation and the direct heating of the atmosphere. These complex surface-atmosphere interactions demonstrate the suitability of high-frequency micrometeorological measurements for achieving water balance closure and predicting local climate impacts.