Sentinel 1

The Sentinel-1 core ground segment allows all Sentinel-1 data to be systematically acquired, processed and distributed [1]. Within the core ground segment, the S-1 Mission Performance Center (MPC) is responsible for calibration, validation, quality control and end-to-end system performance assessment of the products [2]. The MPC includes expert teams for specific Cal/Val, online and offline quality control, algorithm correction and evolutions for the SAR processor both for Level 1 (SLC and GRD) and Level 2 (OCN) products.

The purpose of this presentation is threefold:

First, to present the organization of the MPC and the team covering both L1 and L2 experts, and how the QC/Cal/Val activities on Level 1 products benefits to the L2 products.

Second, to present the main evolutions of the SAR processing baseline for both Sentinel-1A and 1B since their respective start of operations and the planned evolutions. More detailed information of the Level 2 product status will be presented by the members of the Expert Support Laboratories of the MPC, also attending to the workshop.

Finally, to present how the Sentinel-1 product user can access the most up to date information on the Sentinel-1 status and performances and contact the MPC if they want to raise specific questions. This includes presentation of links to the appropriate documentation (IPF release note for S-1 product end users, Cyclic and Annual Performance reports, etc), web sites (QC Web Site, Sentinel Online, etc) and forum / social medias.

This presentation aims to complement the presentation of the mission status by ESA and to provide contact points for the oceanographic users.

[1] https://sentinel.esa.int/web/sentinel/missions/sentinel-1/ground-segment/core-ground-segment

[2] https://sentinel.esa.int/web/sentinel/missions/sentinel-1/ground-segment/core-ground-segment/pdgs

The S1 Level-2 WV OCN product contains three geophysical components: the radial surface velocity (RVL), the ocean surface wind field (OWI) and the ocean swell wave spectra (OSW). The OCN product contains also co-located wind speed and direction from the global atmospheric model of ECMWF. The main difference between the former ASAR WM Level 2 product and S1 OCN product is higher range bandwidth (74.5 MHz versus 16 MHz) and larger imagettes (20x20km²) versus 5x5km²) allowing improved detection of very short waves and very long swell systems. In addition, the S1 OCN product contains also an RVL component providing estimates of Doppler centroid (DC) frequency and the corresponding radial velocity. As part of the Level 2 processing, full resolution cartesian cross spectra (CCS) are generated by inter-looking the SLC image providing complex spectra with range spectral components down to around 5 meters. The CCS product is an internal product of the Sentinel 1 IPF OCN processor, but not currently provided within the L2 netCDF product due to the size of the data.  It is well known that the CCS can provide ambiguity free estimate of the ocean wave spectra, and with the high bandwidth of Sentinel 1 WV mode, directional properties of short wave (wind driven) spectra can be revealed. The CCS is shown to provide useful proxy for the range wind speed component, and thus also for the Doppler centroid anomaly (DCA). In this paper we describe an optimal resampling of the CCS such as to reduce the data volume to fit within next version of L2 OCN netCDF product, and still preserve the spectral shape in the region of interest. We also present some perspectives for estimation of new spectral metrics which can be applied for Doppler calibration, NRCS monitoring, wind estimation, and RAR MTF estimation.