NASA’s Physical Oceanography Distributed Active Archive Center (PO.DAAC) released reprocessed Level 1A (L1A), Level 1B (L1B), Level 2 (L2), Level 2P (L2P), and Level 3 (L3) altimetry data from the Sentinel-6 Michael Freilich (Sentinel 6A) radar altimeter mission. This mission aims to provide high-precision measurements of global sea-level that build upon the extensive record of observations from the previous Jason series altimetry missions. Datasets in this release were processed with the latest Sentinel-6 processing baseline (G01).
The new baseline collection G01 adds a major improvement to both low-resolution (LR) and high-resolution (HR) products by incorporating the Generated Data Record-Geophysical (GDR-G) standards, including a new orbit solution following Precision Orbit Ephemerides-Geophysical (POE-G) standards. In addition, the new baseline also adds C band complex echoes in Level 1A altimetry products when the Poseidon-4 instrument is operating in RAW mode, removes maximum likelihood estimation (MLE3) variables from Level 2 products, and adds vertical wave motion correction at 20Hz for HR, NR, and for SAR Altimetry Studies and Applications (SAMOSA) in Level 2 products. Lastly, Version G01 resolves anomalies as described in the Product Notice.
The reprocessed data included in this release cover the time frame from the start of the mission through present. These new datasets are considered Version G01. The corresponding “Version F08” datasets are retired as of this data release. Users are reminded that they should switch to the datasets listed below to obtain NTC data from PO.DAAC going forward. NRT and STC data will continue to be available through the original datasets released for Version F08.
Data Access
The reprocessed datasets can be accessed through NASA Earthdata Search. They are also accessible via the DOI links listed below, which redirect to the corresponding dataset landing pages.
- L1A P4 Altimeter High Resolution (HR) NTC Intermediate Outputs with Instrument Calibrations G01 DOI: 10.5067/S6AP4-1AHNTR-G01
- L1B P4 Altimeter Low Resolution (LR) NTC Geolocated Waveforms G01 DOI: 10.5067/S6AP4-1BLNTR-G01
- L1B P4 Altimeter High Resolution (HR) NTC Geolocated Waveforms G01 DOI: 10.5067/S6AP4-1BHNTR-G01
- L2 P4 Altimeter Low Resolution (LR) NTC Ocean Surface Topography (Unvalidated) G01 DOI: 10.5067/S6AP4-2LSNUR-G01
- L2 P4 Altimeter Low Resolution (LR) NTC Ocean Surface Topography G01 DOI: 10.5067/S6AP4-2LSNTR-G01
- L2 P4 Altimeter Low Resolution (LR) NTC Reduced Ocean Surface Topography (Unvalidated) G01 DOI: 10.5067/S6AP4-2LRNUR-G01
- L2 P4 Altimeter Low Resolution (LR) NTC Reduced Ocean Surface Topography G01 DOI: 10.5067/S6AP4-2LRNTR-G01
- L2 P4 Altimeter High Resolution (HR) NTC Ocean Surface Topography (Unvalidated) G01 DOI: 10.5067/S6AP4-2HSNUR-G01
- L2 P4 Altimeter High Resolution (HR) NTC Ocean Surface Topography G01 DOI: 10.5067/S6AP4-2HSNTR-G01
- L2 P4 Altimeter High Resolution (HR) NTC Reduced Ocean Surface Topography (Unvalidated) G01 DOI: 10.5067/S6AP4-2HRNUR-G01
- L2 P4 Altimeter High Resolution (HR) NTC Reduced Ocean Surface Topography G01 DOI: 10.5067/S6AP4-2HRNTR-G01
- L2 Advanced Microwave Radiometer (AMR-C) NTC Geophysical Parameters G01 DOI: 10.5067/S6AMW-2NTCVR-G01
- L2 Advanced Microwave Radiometer (AMR-C) NTC Geophysical Parameters (Unvalidated) G01 DOI: 10.5067/S6AMW-2NTCUR-G01
- L2P P4 Altimeter Low Resolution (LR) NTC Ocean Surface Topography G01 DOI: 10.5067/S6AP4-2PLNTR-G01
- L2P P4 Altimeter High Resolution (HR) NTC Ocean Surface Topography G01 DOI: 10.5067/S6AP4-2PHNTR-G01
- L3 P4 Altimeter Low Resolution (LR) NTC Ocean Surface Topography (Unfiltered) Version G01 DOI: 10.5067/S6AP4-3LNTCR-G01
- L3 P4 Altimeter High Resolution (HR) NTC Ocean Surface Topography (Unfiltered) Version G01: 10.5067/S6AP4-3HNTCR-G01
Reprocessed Sentinel-6 datasets are also available from EUMETSAT. Minor differences between datasets distributed by EUMETSAT and PO.DAAC are described in the Product Notice.
Citation
Please cite the datasets according to this template when used in future publications:
Ocean Surface Topography Science Team. 2025. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/
Related Resources
Access resources for accessing Sentinel-6 Michael Freilich data from PO.DAAC through the NASA Earthdata Cloud archive in Amazon Web Services (AWS):
Scripted Access to PO.DAAC Data in the Cloud
Video Tutorial - this video tutorial and accompanying data subscriber script provide a user guide on scripted access to PO.DAAC data in the Earthdata Cloud. Users are free to use it as a building block, and modify it for use with Sentinel-6 MF data.
Data subscriber - example script on how to download data given a PO.DAAC collection short name.
PO.DAAC Cookbook - new centralized location that is a key source for all information about cloud data access and resources, including Sentinel-6 MF. More resources are continuously being added.
If you have questions, please contact PO.DAAC user services or visit PO.DAAC on Earthdata Forum.