the Sience Products from the SMOS CATDS: From Level 2 to Level 4
Kerr, Yann¹; Cabot, François¹; Boutin, Jacqueline²; Reul, Nicolas³; Pellarin, Thierry⁴; Wigneron, Jean-Pierre⁵; Albitar, Ahmad¹; Jacquette, Elsa⁶; Berthon, Lucie¹; Guibert, Sarah⁶; Larigauderie, Carole⁶; Cherchali, Selma⁶; Bircher, Simone¹; Tarot, Stéphane³; Delcroix, Thierry⁷; Mialon, Arnaud¹
¹CESBIO, FRANCE; ²LOCEAN, FRANCE; ³IFREMER, FRANCE; ⁴LTHE, FRANCE; ⁵INRA-EPHYSE, FRANCE; ⁶CNES, FRANCE; ⁷LEGOS, FRANCE

The SMOS mission is an ESA led mission involving France (CNES) and SPAIN (CDTI) It was successfully launched on November 2nd 2009 and has been operating since. SMOS enables to derive for the first time directly and from space both Soil moisture and Ocean salinity (Kerr et al 2001 end 2012). The SMOS coverage is done twice (~6 am and 6pm) over the whole globe inless than 3 days. Data, received in Svalabard or in Villafranca is processed at the ESA ESAC Center (DPGS the European Space Agency's Data Processing Ground Segment) up to Level 2 data(geophysical products in swath mode i.e., 1/2 orbits) to be distributed to users (including the Near Real Time products).
The CNES (Centre National d'Etudes Spatiales) with IFREMER and CESBIO has developed the CATDS (Centre Aval de Traitement des Données SMOS) ground segment to produce level 3 and 4 data. Those are spatial and temporal synthesis products (the Level 3 products) of soil moisture, ocean salinity and brightness temperature, which are now covering the whole SMOS operation period, from January 2010 up to now.
The soil moisture products are not simple aggregation of L2 data but use a sophisticated algorithm enabling to fully use SMOS characteristics to have an enhanced product. It is then produced with different temporal resolutions (daily, 3-day global "instantaneous" products as well as 10 day and monthly composites). Over the oceans similarly, spatio temporal composites are elaborated either using the L2 products from ESA or reprocessing the data from level to address specific issues over oceanic surfaces.
The CATDS is now developing Level 4 products for both land and ocean or cryopshere. Level 4 are products elaborated from SMOS data and other products either from other space missions or model etc and often enough over specific areas, regions or periods. Currently we are preparing products consisting of root zone soil moisture, dis- aggregated soil moisture fields, drought indices, flood alerts, hurricane monitor, freeze thaw maps, rainfall maps SMOS- Aquarius / Scat / AMSR merged products etc..; This products are science products made with other groups and entities are currently being developed or validated. The concept is also to help groups preparing and validating the data using one of the two expertise centers ( CESBIO and IFREMER Brest) by ahvaing access to SMOS expertise, SMOS data and computing facilities.
All the CATDS products are available in NetCDF format and are mapped on the EASE grid (Equal Area Scalable Earth grid) with a spatial resolution of ~ 25*25 km2. Moreover, a new product provides brightness temperatures at H and V polarizations which are computed at fixed incidence angles every 5 degrees. The aim of this communication is then to present this the different products with the validation approach as well as general organization of the products and how to get access to them.

References
L. Berthon, A. Mialon, F. Cabot, A. Al Bitar, P. Richaume, Y.H. Kerr, D. Leroux, S. Bircher, H. Lawrence, A. Quesney and E. Jacquette, "CATDS Level 3 Data Product Description - Soil Moisture and Brightness Temperature part", Tech. Rep. SO-TN-CB-CA-0001, Issue 1.b, 10/2012.
E. Jacquette, A. Al Bitar, Y. Kerr, A. Mialon, A. Quesney, F. Cabot, and P. Richaume, "Overview of SMOS CATDS Level 3 soil moisture products," in IGARSS 2010, July 25-30, Honolulu, USA, 2010.
E. Jacquette, A. Al Bitar, A. Mialon, Y.H. Kerr, A. Quesney, F. Cabot, and P. Richaume, "SMOS CATDS Level 3 global products over land," in Proc. SPIE 7824, 78240K, 2010.
Y. H. Kerr, P. Waldteufel, P. Richaume, J.-P. Wigneron, P. Ferrazzoli, and R. Gurney, "SMOS Level 2 processor for soil moisture - Algorithm Theoretical Based Document (ATBD)," Tech. Rep. SO-TN-ARR-L2PP-0037, Issue 3.6, 12/2011.
Kerr, Y. H., et al. (2010). "The smos mission: New tool for monitoring key elements of the global water cycle." Proceedings of the Ieee 98(5): 666-687.
Kerr, Y. H., et al. (2001). "Soil moisture retrieval from space: The soil moisture and ocean salinity (smos) mission." IEEE Trans. Geosci. Rem. Sens. 39(8): 1729-1735.
Y. H. Kerr, P. Waldteufel, P. Richaume, A. Mahmoodi, J.-P. Wigneron, P. Ferrazzoli, A. Al bitar, F. Cabot, D. Leroux, A. Mialon, and S. Delwart, "The SMOS soil moisture retrieval algorithm," IEEE Geosc. Remote Sens., 2011, 50(5): 1351-1353.
A. Al Bitar, E. Jacquette, O. Merlin, Y. Kerr, A. Mialon, A. Quesney, F. Cabot, and P. Richaume, "Multi-orbit inversion of SMOS surface soil moisture" in IGARSS, 25-30 July 2010, Honolulu, USA, 2010.
A. Al Bitar, E. Jacquette, Y. Kerr, A. Mialon, F. Cabot, A. Quesney, O. Merlin, and P. Richaume, "Event detection of hydrological processes with passive L-band data from SMOS," in Proc. SPIE 7824, 78240J, 2010.