ALEX: ALqueva hydro-meteorlogical EXperiment

The aim of the project is to perform an observational Experiment in Alqueva (ALEX 2014), including measurements in the water and in the air columns,
and over the water-atmosphere interface. The team proposes to undertake an integrated field campaign with measurements of chemical, physical and
biological parameters. Through the campaign, we intend to take advantage of existing scientific, especially those belonging to the CGE, including new
equipment being purchased under the Inalentejo/QREN project “Laboratory Sciences and Technologies of Earth, Atmosphere and Energy”.
In addition to the team members, other researchers will be challenged to participate in the observation campaign, offering their resources and sharing
data.
The observations will result in a inter-disciplinary database useful for the researchers working on Alqueva, not only for the team members, but also for
the national scientific community. This database will include in addition to the measurements made by the experimental apparatus specifically et up for
this purpose, others arising from other observations made continuously by other organizations such as the APA (former INAG), the IPMA and the CGE,
as well as information from remote sensing satellite.
The observation campaign include:
Atmosphere
-Vertical profiles obtained by measurement with the microwave profiler in acquisition by CGE and by radiosondes
-Atmospheric composition: aerosols and gases
-Near surface meteorological conditions
-Global and direct solar radiation (using the sun tracker)
Air-water interface
momentum, energy, H2O and CO2 turbulent fluxes over the water (eddy covarience measurements)
Surface-energy balance
Water column:
-Water temperature profiles
-characterization of biological elements present in the water column, including phytoplankton, cyanobacteria and diatoms.
- Dissolved oxygen and other chimical profiles,
-Turbidity and Secchi disk dept
-Profiles of the downward solar radiation spectrum which enable the computation of the attenuation coefficient of light in water
The project team includes researchers with experience in meteorological, atmospheric physics and water quality measurements (e.g. Salgado and Le
Moigne, 2010; Potes et al., 2011 and 2012; Rosado et al., 2012; Costa et al., 2006) . The ALEX 2014 experiment takes advantege of the experience
gained in the the THAUMEX 2011 (Le Moigne et al., 2013). The participation of the EDIA in the project is a guarantee that theirr achievement may be
useful in the improvement of the environmental management of the reservoir.
Among the measurements to perform, we highlight some of the less common:
Eddy covariance measurements, using the new IRGASON Integrated CO2 and H2O Open-Path Gas Analyser and 3D Sonic Anemometer, of
evaporation, CO2 and energy fluxes. Worldwide, there are few reported measurements over lakes as evidenced by Nordbo et al. (2011).
-Profiles with the new microwave profiler, that will be confronted with those obtained by the radiosondes. To our knowledge, this is the first microwave
profiler in the country so its validation has a particular interest.
-Profiles of the spectral solar radiation inside water. These measurements are carried out with the apparatus developed by team members and
described in Potes et al. (2013), which will be improved. These measurements allows estimating the attenuation coefficient, which is a relevant physical
parameter in numerical modelling of water-air transfers. Simultaneous measurement of radiative profiles and of temperature, oxygen and other
chemical and biological parameters will lead new data for water column energy and the dynamics studies.
- Direct solar radiation using a pyrheliometer and a sun tracker. In addition to the interest on the radiative transfer between the water and the
atmosphere, the data provided by the pyrheliometer will be very useful in assessing the direct normal irradiation (DNI) a parameter of great significance
to the solar concentrators technology, being tested in the Alentejo region.
-Among biological elements, diatoms will be analysed more attentively, since studies on planktonic diatoms of reservoirs are rare and several taxa can
form colonies as an adaptation to the planktonic life.
This database shall be usefull in order to:
-Support the management of the reservoir;
- calibrate lake models - in particular the Flake (Mironov et al. 2,010)
-Improve parametrization of lakes in numerical weather prediction
-Validate 3D atmospheric simulations in mesoscale and LES modes
- Re-assess the effects of climate Alqueva in the region, continuing the previous work of the PI (Salgado, 2006)
- characterize the atmospheric boundary layer
-develop and calibrate algorithms for satellite monitoring of water quality
- characterize energy resources: solar (global and DNI) and wind
- obtain CO2 outgassing estimates
- compute the Energy-and the water balance of the reservoir