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Description

These Sea Surface Height Anomalies (SSHA) are derived from the Jason-1 Geophysical Data Record (GDR). Jason-1 is an altimetric mission whose instruments make direct observations of the following quantities: altimeter range, significant wave height, ocean radar backscatter cross-section (a measure of wind speed), ionospheric electron content (derived by a simple formula), tropospheric water content, and position relative to the GPS satellite constellation. Using the various parameter the SSHA can be calculated and are provided in this dataset. The data are in NetCDF format. This dataset only contains the parameters that are directly related to SSHA.

Product Summary

Platforms
JASON-1
Instruments
JASON-1 Microwave Radiometer ,
POSEIDON-2
Spatial Extent

N: 66.15 S: -66.15 E: 180 W: -180

Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2002-01-14 to 2012-03-03
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C1940471193-POCLOUD
Data State
COMPLETE
Number of Files/Granules
92126
Processing Level
2
Published
Updated
Science Keywords
Sea Surface Height ,
Significant Wave 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

JASON-1. (2015). Jason-1 GDR SSHA version E NetCDF [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/J1GPR-NC00E Date Accessed: 2025-12-14

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Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
alt Altitude of satellite above the reference ellipsoid. m float 1.0E+30 N/A 1
alt_echo_type The altimeter echo type is determined by testing the rms of the high rate range measurements against a threshold as well as the number of valid high rate range measurements against a minimum value N/A byte 127 N/A 1
bathymetry ocean depth/land elevation m int 2147483647 N/A 1
hf_fluctuations_corr Provided as a correction to the inverted barometer correction (inv_bar_corr) m short 32767 N/A 0.0001
ice_flag See Jason-1 User Handbook N/A byte 127 N/A 1
inv_bar_corr Computed at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. See Jason-1 User Handbook m short 32767 N/A 0.0001
iono_corr_alt_ku An ionospheric correction must be added (negative value) to the instrument range to correct this range measurement for ionospheric range delays of the radar pulse. See Jason-1 User Handbook m short 32767 N/A 0.0001
lat Positive latitude is North latitude, negative latitude is South latitude. See Jason-1 User Handbook. degrees_north int N/A N/A 1.0E-6
lon East longitude relative to Greenwich meridian. See Jason-1 User Handbook. degrees_east int N/A N/A 1.0E-6
mean_sea_surface The mean sea surface height is referenced to a 20 years mean. See Jason-1 User Handbook. m int 2147483647 N/A 0.0001
mean_topography The mean dynamic topography is referenced to a 20 years mean. See Jason-1 User Handbook. m int 2147483647 N/A 0.0001
model_dry_tropo_corr Computed at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. A dry tropospheric correction must be added (negative value) to the instrument range to correct this range measurement for dry tropospheric range delays of the radar pulse. See Jason-1 User Handbook m short 32767 N/A 0.0001
ocean_tide_sol1 Solution 1 corresponds to GOT4.10 model. Includes the corresponding loading tide (load_tide_sol1) and equilibrium long-period ocean tide height (ocean_tide_equil). The permanent tide (zero frequency) is not included in this parameter because it is included in the geoid and mean sea surface (geoid, mean_sea_surface). See Jason-1 User Handbook m int 2147483647 N/A 0.0001
pole_tide See Jason-1 User Handbook m short 32767 N/A 0.0001
rad_liquid_water Should not be used over land. kg/m^2 short 32767 N/A 0.01
rad_rain_flag See Jason-1 User Handbook. The radiometer rain flag indicates where the radiometer wet troposphere path delay (rad_wet_tropo_corr) is invalid due to rain contamination N/A byte 127 N/A 1
rad_sea_ice_flag See Jason-1 User Handbook. The radiometer sea ice flag indicates where the radiometer wet troposphere path delay (rad_wet_tropo_corr) is invalid due to sea ice contamination N/A byte 127 N/A 1
rad_surf_type The radiometer surface type flag is applicable to the radiometer wet troposphere path delays provided by rad_wet_tropo_corr. A value of 0 indicates that open ocean processing is used to compute the path delay, 1 indicates coastal processing is used, and 2 indicates the path delay is invalid due to land N/A byte 127 N/A 1
rad_water_vapor Should not be used over land. kg/m^2 short 32767 N/A 0.1
rad_wet_tropo_corr A wet tropospheric correction must be added (negative value) to the instrument range to correct this range measurement for wet tropospheric range delays of the radar pulse m short 32767 N/A 0.0001
rain_flag See Jason-1 User Handbook N/A byte 127 N/A 1
range_ku All instrumental corrections included, i.e. distance antenna-COG (cog_corr), USO drift correction (uso_corr), internal path correction (internal_path_delay_corr_ku), Doppler correction (doppler_corr_ku), modeled instrumental errors correction (modeled_instr_corr_range_ku) and system bias. range updated to account for reference plane and internal path delay m float 1.0E+30 N/A 1
sea_state_bias_ku Computed using wind speed from sigma0 using updated atmospheric attenuation values. A sea state bias correction must be added (negative value) to the instrument range to correct this range measurement for sea state delays of the radar pulse. This element should not be used over land. See Jason-1 User Handbook m short 32767 N/A 0.0001
sig0_ku All instrumental corrections included, excepted the system bias, i.e. AGC instrumental errors correction, internal calibration correction (internal_corr_sig0_ku), modeled instrumental errors correction (modeled_instr_corr_sig0_ku) and atmospheric attenuation (atmos_corr_sig0_ku) dB short 32767 N/A 0.01
solid_earth_tide Calculated using Cartwright and Tayler tables and consisting of the second and third degree constituents. The permanent tide (zero frequency) is not included. See Jason-1 User Handbook m short 32767 N/A 0.0001
ssha = altitude of satellite (alt) - Ku band corrected altimeter range (range_ku) - altimeter ionospheric correction on Ku band (iono_corr_alt_ku) - model dry tropospheric correction (model_dry_tropo_corr) - radiometer wet tropospheric correction (rad_wet_tropo_corr) - sea state bias correction in Ku band (sea_state_bias_ku) - solid earth tide height (solid_earth_tide) - geocentric ocean tide height solution 1 (ocean_tide_sol1) - geocentric pole tide height (pole_tide) - inverted barometer height correction (inv_bar_corr) - high frequency fluctuations of the sea surface topography (hf_fluctuations_corr for I/GDR off line products only) - mean sea surface (mean_sea_surface). Set to default if the altimeter surface type (surface_type) is set to 1, 2, or 3 (lake_enclosed_sea, ice, or land) m short 32767 N/A 0.001
surface_type Computed using a DTM2000 file: 0 = open oceans or semi-enclosed seas; 1 = enclosed seas or lakes; 2 = continental ice; 3 = land. See Jason-1 User Handbook N/A byte 127 N/A 1
swh_ku All instrumental corrections included, i.e. modeled instrumental errors correction (modeled_instr_corr_swh_ku) and system bias m short 32767 N/A 0.001
time [tai_utc_difference] is the difference between TAI - UTC (i.e., leap seconds) for the first measurement of the data set. [leap_second] is the UTC time at which a leap second occurs in the data set, if any. After this UTC time, the [tai_utc_difference] is increased by 1 second. time variable is corrected from datation bias. See Jason-1 User handbook. seconds since 2000-01-01 00:00:00.0 double N/A N/A 1
wind_speed_alt Should not be used over land. See Jason-1 User Handbook m/s short 32767 N/A 0.01
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