ENVISAT ASAR products are operationally distributed to the user community since December 2002 (since January 2004 for Global Monitoring Mode). Calibration activities, based on the ASAR internal calibration modes and on acquisitions over transponders, corner reflectors and the Amazon Rain forest, are routinely performed to ensure the accurate calibration of ASAR products. In addition, some changes have been introduced in PF-ASAR (ASAR Processing Facility) to further improve the quality of the products and a new product, the Wide Swath Mode Single Look Complex (WSS) product, is being implemented in the processor. This paper presents the different calibration activities, the calibration results and an updated quality status for the different ASAR products. It introduces also the new WSS product, which will be available to the users before the end of 2004. INTRODUCTION The ENVISAT Advanced Synthetic Aperture Radar (ASAR), one of the 10 instruments on board of ENVISAT, is equipped with an active phased array antenna of 320 transmit/Receive modules, organised in 32 rows to produce a versatile position of the image swath by beam steering in elevation. In addition, the instrument is designed to provide a large degree of operational flexibility, acquiring science data in 5 different modes. The Image Mode (IM) generates high spatial resolution data, in HH (H Transmit and H receive) or VV (H Transmit and H receive) polarization, over one of seven available swaths located over a range of incidence angles spanning 15 ° to 45 °. The Wave Mode (WV) generates vignettes of 10 km by 10 km spaced 100 km along-track, in HH or VV polarisation. The position of the vignette can be selected to alternate between the centre of any two of the seven swaths. The Wide Swath Mode (WSM) and Global Monitoring Mode (GMM) are based on the ScanSAR technique using five sub-swaths (across track coverage of 400 Km) either in HH or in VV polarisation. The first one is a high resolution mode, for which typical products of 150 m geometric resolution are generated, while the second one is a low rate mode, which allows for a whole orbit operation at the cost of reducing the resolution to ~1Km. The Alternating Polarisation (AP) Mode provides two simultaneous images from the same area in HH and VV polarizations, HH and HV or VV and VH, using the ScanSAR technique, with the same imaging geometry as Image Mode and similarly high spatial resolution. [1] Monitoring the instrument performance and product quality is a major task is to be performed during the instrument lifetime in order to ensure the maximum data quality throughout the full mission. This paper provides an overview of the ASAR product quality based on dedicated calibration sites, describes recent improvements in the product quality and introduces a new product type, the Wide Swath Complex, which is being implemented in the operational ASAR processor and which will be available to the users before the end of 2004. ASAR OPERATIONS: GLOBAL MONITORING ASAR science data is acquired operationally in Image, Alternating Polarisation, Wave and Wide Swath mode since mid 2002. Some anomalies at instrument level were observed while operating in Global Monitoring mode. These included the corruption of source data packets and an abnormal mode termination. Operations in GM were suspended during the investigation, until a corrective solution was available. A solution to both problems was identified and implemented in November 2003. Test operations started in December 2003 and nominal operations, through an upgraded Background Regional Mission (BRM) Plan were resumed in February 2004. Quality of GM data is nominal since then and products are being distributed in near real time (NRT) to users since March 2004. Some examples of GM products are provided in Fig.1 The BRM establishes the default acquisition plan in absence of user requests. Different levels of priority are defined, being the low rate data (Wave and Global Monitoring modes) the modes with lower priority. Availability of data around the orbit is crucial to perform the around-orbit performance monitoring and to identify possible anomalies as early as possible. Until February 2004, the low rate BRM was based only on wave mode. In other words, wave mode data was acquired over any type of area (ocean, land, ice, sea-ice...) when no high rate data was required. Since February 2004, wave mode data is acquired only over the oceans while global monitoring data is acquired both over land and over ice and sea-ice areas. Fig. 1. Examples of Global Monitoring Mode products acquired in May 2004. ASAR CALIBRATION SITES Calibration of ASAR products and monitoring of ASAR product quality is performed based on data acquired over various calibration sites, namely: the 4 ASAR precision transponders, currently deployed in The Netherlands the 4 RADARSAT transponders, deployed in Canada and used for ASAR performance monitoring under agreement with the Canadian Space Agency (CSA) ASAR receiving ground stations the Amazon Rain Forest area corner reflectors deployed for specific calibration campaigns 1 2