Altimetry Near-Real-Time¶
| Dataset Name | Sensor | Make | Spatial Resolution | Temporal Resolution | Start Date | End Date |
|---|---|---|---|---|---|---|
| Altimetry Near-Real-Time |  |
Observation | 1/4° X 1/4° | Daily | 2019-01-01 | 2019-04-28 |
Dataset Description¶
The near-real-time altimetry dataset in CMAP was provided by CMEMS. It is a 1/4° daily global gridded satellite product of sea level altimetry and derived variables (sla,adt,vgos,vgosa,ugos,ugosa). Sea Level Anomaly (SLA) measurements were calculated with respect to a twenty year average from 2012. Altimeter satellite gridded Sea Level Anomalies (SLA) computed with respect to a twenty-year 2012 mean. The SLA is estimated by from the along-track Level 3 altimetry product and then Optimal Interpolated to produce a near-real-time altimetry products
A more detailed description of the processing techniques can be found [here](http://marine.copernicus.eu/services-portfolio/access-to-products/?option=com_csw&view=details&product_id=SEALEVEL_GLO_PHY_L4_NRT_OBSERVATIONS_008_046). Quality control and sources of error are described in detail in the CMEMS [Sea Level Quality Information Document](http://resources.marine.copernicus.eu/documents/QUID/CMEMS-SL-QUID-008-032-062.pdf). In summary, the source of error partially depends on the number of satellites per observation. QA checks of the gridded product are done by comparing measurements against in-situ tide gauge readings. With only two altimeters overhead, SLA errors in the low variability areas such as the open ocean can reach 1.4 cm², while the error in high variability areas reaching up to 37.7 cm². Errors within coastal areas (defined as within 200 km of land), are typically 8.2 cm².
The CMEMS internal name for this dataset is: SEALEVEL_GLO_PHY_L4_NRT_OBSERVATIONS_008_046.
Table of Variables¶
How to Acknowledge¶
Data provided by: E.U. Copernicus Marine Service Information