Interactions lake-atmosphere under Mediterranean conditions: ALEX 2014 observations and simulations.

Abstract

The ALqueva hydro-meteorological EXperiment, ALEX 2014, was an integrated field campaign (http://www.alex2014.cge.uevora.pt) with measurements of chemical, physical and biological parameters in water and air at the Alqueva reservoir, a 250 km2 man made lake, in the southeast of Portugal. The ALEX 2014 took place from June 1 to September 30, 2014 and includes an Intensive Observation Period (IOP) of three days (22 to 24 July). During the IOP, radiosondes were launched every tree hours, allowing a good characterization of the atmospheric boundary layer and its evolution. Simultaneously, energy, vapor and momentum fluxes between the water and the air were measured using the new IRGASON eddy covariance system, installed on a floating platform. This platform were instrumented in order to measure, among other parameters: solar and thermal downward and upward radiative fluxes, air temperature and humidity, wind speed and water temperature at 9 different depths. The ALEX 2014 includes also several surface meteorological stations in order to characterize the local horizontal structure of surface atmospheric fields and detect lake effects. The lake-atmosphere interactions and its impact in the boundary layer structure and in the local circulations are studied using data collected during the ALEX 2014 POI together with results from numerical simulations performed with the non-hydrostatic Meso-NH french model.