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Description

This dataset contains along track geo-referenced Sea Surface Height Anomalies (SSHA) from TOPEX/Poseidon, Jason-1, OSTM/Jason-2 and Jason-3 (depending on time period) merged into a single mean reference orbit. All biases and cross-calibrations have been applied to the data so SSHA are consistent between satellites to form a single climate data record. Altimeter data from the multi-mission Geophysical Data Records (GDRs) are interpolated to a common reference orbit facilitating direct time series analysis of the geo-referenced SSH. However this product does not use the TOPEX internal calibration-mode range correction. This is the main difference between version 4 and version 4.2. More information on this calibration can be found at Beckley et al. 2017 DOI 10.1002/2017JC013090. The data are in netCDF format. Each file consists of one cycle of data, which is approximately 10 days long. Cycle 001 coincides with cycle 001 of TOPEX/Poseidon (September 25-October 3, 1992).

Product Summary

Platforms
OSTM/JASON-2 ,
JASON-1 ,
TOPEX/POSEIDON ,
JASON-3
Instruments
AMR ,
POSEIDON-3 ,
JASON-1 Microwave Radiometer ,
POSEIDON-2 ,
TMR ,
ALT (TOPEX) ,
SSALT ,
POSEIDON-3B
Projects
MEaSUREs
Spatial Extent

N: 66 S: -66 E: 180 W: -180

Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
1992-09-25 to 2020-01-25
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C1940466008-POCLOUD
Data State
DEPRECATED
Number of Files/Granules
1006
Processing Level
2
Published
Updated
Science Keywords
Sea Surface Height

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

GSFC. (2017). Integrated Multi-Mission Ocean Altimeter Data for Climate Research Version 4.2 [Dataset]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/ALTCY-TJ142 Date Accessed: 2026-10-27

Documents

USER'S GUIDE

DATA CITATION GUIDELINES

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Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
Bathymetry Bathymetry m short 32767 N/A 1 N/A
Distance_to_coast Along Track Distance to Coast m int 2147483647 N/A 1 N/A
flag Flag value for representing different errors in the sea surface height anomaly estimates N/A short N/A 0 to 32767 1 N/A
index Specifies the index number of the lon/lat position of a 1Hz data point in a reference_orbit revolution N/A short N/A 1 to 6746 1 N/A
latitude Positive latitude is North latitude, negative latitude is South latitude. FillValue pads the reference orbits to have same length degrees_north int 2147483647 -66149120 to 66149330 1.0E-6 N/A
longitude East longitude relative to Greenwich meridian. FillValue pads the reference orbits to have same length degrees_east int 2147483647 596 to 359999800 1.0E-6 N/A
mss Mean Sea Surface Height above Reference Ellipsoid mm int 2147483647 N/A 1 N/A
reference_orbit Specifies the number of the revolution within a near 10-day repeat orbit N/A short N/A 1 to 127 1 N/A
ssh Sea Surface Height Anomaly mm short 32767 -12508 to 32532 1 N/A
Surface_Type Type of Surface None byte 9 N/A 1 N/A
time Conversion to Modified Julian Day + fraction of day (accurate to a second): MJD = time/86400.0 + 48622.0 seconds int 2147483647 N/A 1 N/A
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