| This communication will present the main results of a series of airborne campaigns conducted at the Valencia Anchor Station (VAS) and Los Monegros site using the EMIRAD L-band radiometer onboard the Short SC.7 Skyvan aircraft from the Technical University of Helsinki (April-May 2008) and the CAROLS (Combined Airborne Radio-instruments for Ocean and Land Studies) radiometer on board the ATR 42 aircraft from Météo-France (April-May 2009 and April-June 2010). The main objective was to contribute to the implementation of the SMOS emission model L-MEB (L-band Microwave Emission model of the Biosphere) in the framework of the validation of SMOS land data and products. Specifically, the objectives of these campaigns were the following:
• Soil moisture validation studies. Flights at the VAS area took place in April-June 2008 in the context of the ESA SMOS Validation Rehearsal Campaign 2008 over a control area of 10 km x 10 km where intensive soil moisture data was acquired concurrently to airborne L-band measurements. One of the objectives of this campaign was to establish homogeneous units to characterize the average soil moisture of that area, and to investigate the possibility of extending the methodology to the whole SMOS validation pixel at the VAS site. The ‘homogeneous units’ characterisation was studied and extended further in the context of CNES CAROLS 2009, and validated during the ESA-CNES CAROLS 2010 campaign. The results of this campaign will be presented in this communication giving emphasis to the validation of the ground definition of the homogeneous environmental units.
• Radiometric characterisation & SMOS data validation. The 10 km x 10 km mentioned above is part of a larger area of ~50 km x 50 km within the VAS SMOS validation pixel. For CAROLS 2009, flights were performed over a 30 km x 50 km area in order to examine the radiometric signature of other surfaces that are present in the VAS SMOS pixel but not in the 10 km x 10 km control area examined in 2008 (mostly dense forests, matorral, and non-flat surfaces). Main results of CAROLS 2009 will be presented in this communication, and the emphasis will be on comparing local to regional scale results given that CAROLS flights were performed at 4000 m above the surface. For 2010, lower altitude flights (~2200 m a.s.l.) over an area of 20 km x 20 km containing a large number of homogeneous units (‘environmental units’), were used for validation of SMOS microwave model L-MEB. The results of this campaign will be presented in this communication, and the emphasis will be on the validation of the L-MEB model.
In addition to the activities at the VAS site, flights over Los Monegros’ salt pans near Zaragoza were performed in the 2010 CAROLS Campaign to study their emissivity at L-band. Three playa-lakes (Guallar, La Playa, and Salineta) were sampled to measure gravimetric soil moisture and electrical conductivity. |