| Mission | Topex |
| MVA-Name | topex_f_hf |
| Source | GDR-F |
| Frequency | 20 |
agc.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -2 | db | agc | Automatic Gain Control
20 Hz Ku-band On-Board Attenuator Gain Control (AGC) as provided in the original SDR, which includes temperature corrections. Source: GDR-F Original-Parameter: agc_20hz_ku |
| 2 | +2 | -2 | db | agc_rms | RMS of AGC
RMS of 20 Hz Ku-band AGC measurements. Only valid 20 Hz measurements are used to compute this element. Source: GDR-F Original-Parameter: agc_rms_ku |
doppler.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | doppler | Doppler Correction
Doppler correction to Ku-band range. Computed using orbit altitude rate (altitude_rate_mean_sea_surface). Source: GDR-F Original-Parameter: range_cor_doppler_ku |
ebias.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | emb | Sea State Bias
Computed using wind speed (wind_speed_alt) and significant waveheight (swh_ku). 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. Applicable to Ku-band MLE4 ranges. Source: GDR-F Original-Parameter: sea_state_bias_ku |
instr.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | +4 | - | sec | isec | Integer Seconds Elapsed Since Epoch
[tai_utc_difference] is the difference between TAI and UTC reference time (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. Source: GDR-F Original-Parameter: time_20hz |
| 2 | +4 | -6 | sec | msec | Microseconds, Fractional Part of isec
[tai_utc_difference] is the difference between TAI and UTC reference time (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. Source: GDR-F Original-Parameter: time_20hz |
| 3 | +4 | -3 | m | ralt | Altimeter Range
20 Hz Ku-band MLE4 range. Net instrument range correction (net_instr_cor_range_ku) has been added. Source: GDR-F Original-Parameter: range_20hz_ku |
| 4 | +2 | -3 | m | stdalt | RMS of Altimeter Range
RMS of 20 Hz Ku-band MLE4 range measurements. Only valid 20 Hz measurements are used to compute this element. Source: GDR-F Original-Parameter: range_rms_ku |
| 5 | 2 | -2 | m | swh | Significant Wave Height
20 Hz Ku-band MLE4 significant waveheight. Instrumental corrections are not required. Source: GDR-F Original-Parameter: swh_20hz_ku |
| 6 | +2 | -2 | m | stdswh | RMS of Significant Wave Height
RMS of 20 Hz Ku-band MLE4 significant waveheight measurements. Only valid 20 Hz measurements are used to compute this element. Source: GDR-F Original-Parameter: swh_rms_ku |
| 7 | +2 | -2 | db | sigma0 | Backscatter Coefficient
Sum of Ku-band AGC, MLE-4 retracked Ku-band echoes amplitude correction (including Ku-band point target response correction, given in net_instr_cor_sig0_ku), amplitude correction to account for satellite altitude, atmospheric attenuation (rad_atm_cor_sig0_ku), and constant Ku-band bias to align with original geophysical data record from side B. Source: GDR-F Original-Parameter: sig0_20hz_ku |
| 8 | +1 | -1 | m/s | windsp | Wind Speed
Sea surface wind speed. Source: GDR-F Original-Parameter: rad_wind_speed |
| 9 | +1 | - | - | iflags | Instrument Status and Quality Flags
Source: GDR-F Original-Parameter: agc_20hz_ku, agc_rms_ku, alt_state_flag_oper, range_numval_ku, rain_flag,ice_flag Flags: 1 : agc_20hz_ku in [32767,0] or agc_rms_ku in [32767,0] or agc_rms_ku/agc_20hz_ku > 0.1 2 : swh_ku in [32767,0] or swh_rms_ku in [32767,0] or swh_rms_ku/swh_ku > 0.1 4 : alt_state_flag_oper == 1 (0: SideA, 1: SideB) 8 : range_numval_ku < 12 16 : alt_state_flag_oper == 2 (0: Topex, 1: Poseidon) 64 : rain_flag != 0 or ice_flag != 0 128 : range_ku == nan or range_rms_ku == nan |
instr.01
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | +4 | - | sec | isec | Integer Seconds Elapsed Since Epoch
[tai_utc_difference] is the difference between TAI and UTC reference time (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. Source: GDR-F Original-Parameter: time_20hz |
| 2 | +4 | -6 | sec | msec | Microseconds, Fractional Part of isec
[tai_utc_difference] is the difference between TAI and UTC reference time (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. Source: GDR-F Original-Parameter: time_20hz |
| 3 | +4 | -3 | m | ralt | Altimeter Range
20 Hz Ku-band MLE3 range. Net instrument range correction (net_instr_cor_range_ku_mle3) has been added. Source: GDR-F Original-Parameter: range_20hz_ku_mle3 |
| 4 | +2 | -3 | m | stdalt | RMS of Altimeter Range
RMS of 20 Hz Ku-band MLE3 range measurements. Only valid 20 Hz measurements are used to compute this element. Source: GDR-F Original-Parameter: range_rms_ku_mle3 |
| 5 | 2 | -2 | m | swh | Significant Wave Height
20 Hz Ku-band MLE3 significant waveheight. Instrumental corrections are not required. Source: GDR-F Original-Parameter: swh_20hz_ku_mle3 |
| 6 | +2 | -2 | m | stdswh | RMS of Significant Wave Height
RMS of 20 Hz Ku-band MLE3 significant waveheight measurements. Only valid 20 Hz measurements are used to compute this element. Source: GDR-F Original-Parameter: swh_rms_ku_mle3 |
| 7 | +2 | -2 | db | sigma0 | Backscatter Coefficient
Sum of Ku-band AGC, MLE-3 retracked Ku-band echoes amplitude correction (including Ku-band point target response correction, given in net_instr_cor_sig0_ku_mle3), amplitude correction to account for satellite altitude, atmospheric attenuation (rad_atm_cor_sig0_ku), and constant Ku-band bias to align with original geophysical data record from side B. Source: GDR-F Original-Parameter: sig0_20hz_ku_mle3 |
| 8 | +1 | -1 | m/s | windsp | Wind Speed
Sea surface wind speed. Source: GDR-F Original-Parameter: rad_wind_speed |
| 9 | +1 | - | - | iflags | Instrument Status and Quality Flags
Source: GDR-F Original-Parameter: agc_20hz_ku, agc_rms_ku, alt_state_flag_oper, range_numval_ku_mle3, rain_flag,ice_flag Flags: 1 : agc_20hz_ku in [32767,0] or agc_rms_ku in [32767,0] or agc_rms_ku/agc_20hz_ku > 0.1 2 : swh_ku_mle3 in [32767,0] or swh_rms_ku_mle3 in [32767,0] or swh_rms_ku_mle3/swh_ku_mle3 > 0.1 4 : alt_state_flag_oper == 1 (0: SideA, 1: SideB) 8 : range_numval_ku_mle3 < 12 16 : alt_state_flag_oper == 2 (0: Topex, 1: Poseidon) 64 : rain_flag != 0 or ice_flag != 0 128 : range_ku == nan or range_rms_ku_mle3 == nan |
invbm.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | invb | Inverse Barometer Effect
Computed at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. See TOPEX User Handbook. Source: GDR-F Original-Parameter: inv_bar_cor |
ionos.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | ionos | Ionospheric correction
No available for Poseidon (alt_state_flag_oper == 2) An ionospheric correction must be added (negative value) to the instrument range to correct for ionospheric delays of the radar pulse. A calibration bias of -0.06945 m has been added to (range_ku + sea_state_bias_ku) - (range_c + sea_state_bias_c) before computing this correction. Source: GDR-F Original-Parameter: iono_cor_alt_ku |
ionos.01
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | ionos | Ionospheric correction
An ionosphere correction must be added (negative value) to the instrument range to correct for ionospheric delays of the radar pulse. This value is generated from Global Ionosphere Maps (GIM) and are only available from repeat cycle 48. Source: GDR-F Original-Parameter: iono_cor_gim_ku |
orbit.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | +4 | -6 | deg | glon | Longitude
East longitude relative to Greenwich meridian. Source: GDR-F Original-Parameter: longitude_20hz |
| 2 | 4 | -6 | deg | glat | Latitude
Positive latitude is North latitude, negative latitude is South latitude. Source: GDR-F Original-Parameter: latitude_20hz |
| 3 | +4 | -3 | m | hsat | Satellite Altitude
Altitude of satellite above the reference ellipsoid (GSFC POD solution). Source: GDR-F Original-Parameter: altitude_20hz |
| 4 | +1 | - | - | oflags | Orbit Status and Quality Flags
Source: GDR-F Original-Parameter: depth_or_elevation, rad_surface_type_flag, alt_echo_type, surface_classification_flag, altitude Flags: 2 : depth_or_elevation > -2000 4 : depth_or_elevation > -200 8 : rad_surface_type_flag != 0 || alt_echo_type != 1 16 : surface_classification_flag != 0 128 altitude == nan |
tidee.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | etide | Solid Earth Tide Correction
Calculated using Cartwright and Tayler tables and consisting of the second and third degree constituents. The permanent tide (zero frequency) is not included. See TOPEX User Handbook. Source: GDR-F Original-Parameter: solid_earth_tide |
| 2 | 2 | -3 | m | ptide | Pole Tide Correction
Adopts Ries and Desai [2017] model for mean pole location. Xp = 55.0 + 1.677*DT, Yp = 320.5 + 3.460*DT in milliarcseconds with DT = years since 2000.0. Source: GDR-F Original-Parameter: pole_tide |
tropd.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | dtrop | Dry Tropospheric Correction
Computed at mean sea level 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 TOPEX User Handbook. Source: GDR-F Original-Parameter: model_dry_tropo_cor_zero_altitude |
tropw.00
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | wtrop | Wet Tropospheric Correction
Value must be added to altimeter range to correct for delay due to the wet troposphere. Source: GDR-F Original-Parameter: rad_wet_tropo_cor |
tropw.01
| Pos | Size | Scaling | Unit | Name | Version Specific Description |
|---|---|---|---|---|---|
| 1 | 2 | -3 | m | wtrop | Wet Tropospheric Correction
Computed at mean sea level at the altimeter time-tag from the interpolation of 2 ERA meteorological fields that surround the altimeter time-tag. 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. See TOPEX User Handbook. Source: GDR-F Original-Parameter: model_wet_tropo_cor_zero_altitude |