The overall objective of the Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment (LIAISE) project is to improve the understanding of land-atmosphere and hydrology interactions in a semi-arid region characterized by strong surface heterogeneity owing to contrasts between the natural landscape and intensive, irrigated agriculture. It is known that irrigation can potentially impact the local atmospheric boundary layer (ABL) characteristics, thereby modifying near surface atmospheric conditions within and downwind of irrigated areas (e.g., Lawston et al., 2020) and potentially the recycling of precipitation. The understanding of the impact of anthropization and its representation in models have been inhibited due to a lack of consistent and extensive observations. In recent years, land surface and atmospheric observation capabilities have advanced while irrigated surfaces have been increasing, leading to a renewed need for dedicated field campaigns over contrasting (climate) regions.
We present a summary of the LIAISE field campaign intensive phase between July 15–29 2021, which took place over the Catalan counties of Urgell and Pla d'Urgell within the Ebro basin in north-eastern Spain. LIAISE is located in a semi-arid hot, dry Mediterranean climate, with a very sharp delineation between a vast, nearly continuous intensively-irrigated region and the generally much more dry rain-fed zone to the east of the study domain. Intensive, spatially distributed surface-based and airborne measurements of the atmospheric boundary layer were made, along with intensive eco-physiological observations and remotely-sensed high spatial resolution mesoscale measures of surface variables from aircraft and unmanned aerial vehicles (UAVs). Two energy budget sites were extended with a network of soil moisture sensors since they were used to evaluate remote sensing data from aircraft. More than 30 institutions took part in the campaign covering a wide range of expertise and spatiotemporal scales in the methods involved, be it through modelling or measurements.
In this contribution we will elaborate on the spatial and temporal scales involved in the processes of evapotranspiration. We will make a strong case for integrated approaches combining observation and modelling techniques to further develop our understanding of evapotranspiration. This will be illustrated with a case study using a mixed layer column model heavily guided and constrained by measurements.
How to cite: Hartogensis, O., Boone, A., Mangan, M.-R., Bellvert, J., Best, M., Brooke, J., Canut-Rocafot, G., Cuxart, J., Le Moigne, P., Miro, J. R., Polcher, J., Price, J., and Quintana Segui, P.: LIAISE campaign: Measuring and Modelling Evapotranspiration over Irrigated Terrain in a Semi-Arid Environment, EMS Annual Meeting 2022, Bonn, Germany, 5–9 Sep 2022, EMS2022-616, https://doi.org/10.5194/ems2022-616, 2022.
