|TITLE||REMOTE SENSING OF THE WATER CYCLE IN THE MEDITERRANEAN|
|AUTHORS||Antonio Turiel (1,2), VerÃ³nica GonzÃ¡lez-gambau (1,2), Estrella Olmedo (1,2), Justino MartÃnez (1,2), Maria Piles (1,2), Jordi Isern-fontanet (1,2), Marcos Portabella (1,2), Joaquim Ballabrera-poy (1,2)|
- Barcelona Expert Center Barcelona (Spain)
- Institute Of Marine Sciences Barcelona (Spain)
|ABSTRACT||With the advent of satellite missions operating passive microwave sensors in L-band (first SMOS, then Aquarius and SMAP) we have open the way to the observation from space of key components of the water cycle (mainly sea surface salinity, SSS, on the ocean and soil moisture, SM, on land). The main advantage of L-band sensors is their almost all-weather capability and the repeated access to synoptic views of the analysed variables; the main drawbacks are the limited resolution (25 kilometer of coarser) and the complexity of the processing. Precisely due to the difficulties to remove some important biases and errors in the brightness temperature signal in L-band, the retrieval of valid SSS values in the Mediterranean has been impossible so far. On the other hand, the characterization of SM in the Mediterranean region often requires maps of higher spatial resolution than that offered by present satellite missions; in addition, the presence of Radio Frequency Interferences (RFI) affects wide areas where no acquisition can be made. As a consequence, the observation of SSS and SM in the Mediterranean area has been limited to scarce satellite observations combined with in situ data since very recently.
The introduction of new processing techniques has changed the situation dramatically. At the Barcelona Expert Center (one of ESA's SMOS Expert Support Laboratory) we have developed new techniques capable to mitigate the known issues about SMOS acquisitions. In particular, we have introduced techniques for removing systematic biases (as land-sea contamination) and RFI effect. We have modified the standard way of retrieving SSS and SM to make the retrieval process more robust and realiable. Finally, we have introduced new data merging techniques in order to improve the space and time resolution of the maps.
In this talk we will present the most recent maps of SSS and SM derived from SMOS for the Mediterranean region. The present six years of data offer a unique view of the process governing freshwater fluxes in the region, and allow to observe specific processes, as the evolution of mesoscale eddies and the circulation of Atlantic inflow waters in the Western Mediterranean. The introduction of these products enables a more than significant improvement of climate services, as for instance the assessment of forest fire risks or the production of agricultural indexes.|