Sentinel-6 L2 Poseidon-4 Altimetry Low Resolution

Poseidon-4 is the primary payload of the Copernicus Sentinel-6 mission. This nadir-pointing dual-frequency SAR altimeter is designed to provide high accuracy and high precision altimetry measurements, including Sea Surface Height (SSH) from the radar range measurement, Significant Wave Height (Hs) and wind speed derived from normalised radar cross section.

Poseidon-4 acquires data simultaneously using SAR processing and conventional Low Resolution Mode (LRM) approaches. The Poseidon-4 antenna is a single symmetrical centre-fed parabolic reflector with a diameter of 1.2 m and a dual frequency centrally fed feed chain at a focal length of about 440 mm. The altimeter's main frequency for surface height measurements is the Ku-band (central frequency: 13.575 GHz, total bandwidth: 320 MHz). The secondary C-band frequency (central frequency: 5.41 GHz, total bandwidth: 320 MHz) is used for ionosphere corrections, rain cell measurements and surface roughness estimates.

The Poseidon-4 Level 2 product contains altimetry measurements such as the altimeter range, sea surface height, wind speed, significant wave height and all required geophysical corrections.

Availability

• Germany: 2021-11-01 - now
• Europe: 2021-11-01 - now
• Global: 2021-11-01 - now

Updates

Systematic continuous updating

Access

Depending on the environment and the intended use, there are several ways to access the data:

• EO Browser: -
• Data Explorer:
  • Data Catalogue: CODE-DE
  • Collection: Sentinel-6
  • Instrument: Poseidon-4 SAR Altimeter
  • Processing Level: Level 2
  • Product Type: P4_2__LR_____
  • Timeliness: selectable: NRT, STC, NTC