Precipitation characteristics and related boundary-layer processes during LIAISE 2021

In the context of the “Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment” (LIAISE), the WISE-PreP project was designed to study precipitation processes aiming to characterize possible differences in precipitation induced by surface characteristics (irrigated vs non-irrigated areas). Instrumentation deployed during the 2021 campaign included three sites equipped each with a vertical radar Doppler Micro Rain Radar (MRR) and a laser disdrometer (PARSIVEL), covering both irrigated and non-irrigated sites. Time series of vertical precipitation profiles are recorded to study microphysical processes trough the evolution of raindrop size distributions and related variables including precipitation intensity or convective vs stratiform rainfall regimes.

The main meteorological variables at the surface are analysed during LIAISE 2021 campaign and compared with A reference period (2010-2019) for irrigated and non-irrigated areas to characterize local differences either related with dynamics or land-use influences, and their influence in the boundary layer development and precipitation initiation.

First results show higher accumulated precipitation in the non-irrigated area (eastern area) than those in irrigated area (western area) in summer 2021, a feature also observed in summers for the reference period. Maximum and minimum daily temperatures are higher in irrigated areas than in non-irrigated areas. Both results are consistent with current climatology based on monthly precipitation and temperature that indicate the existence of a zonal gradient that increases semi-arid conditions (drier and warmer) from the east to the west. Sea-breeze regime also influences the two type areas, with different time arrival and a slight shift in wind components.

Funding for this research was provided by “Analysis of Precipitation Processes in the Eastern Ebro Subbasin” (WISE-PreP, RTI2018-098693-B-C32) and the Water Research Institute (IdRA) of the University of Barcelona.