DUACS DT-2021 altimeter standards

The following table list the standards used in the MY DUACS DT-2021 product version (Lievin et al., 2020).

Bold text indicates the standards that evolved compared to the previous product version (DT-2018; Taburet et al., 2019).

 

Parameter

Version used

Altimeter standards

 
Product standard ref
 
  • Topex/Poseidon :  MGDR
  • Jason-1/2 : GDR-D
  • Jason-3 : GDR-D before 2023/06/07; GDR-F after
  • ERS-1 : -
  • ERS-2 : -
  • Envisat : -
  • SARAL-DP/AltiKa: -
  • Sentinel-6A : F08 before 2023/06/07; F09 after

  • Sentinel-3A/B : BC04 before 2023/06/07; BC05 after

  • Geosat Follow On : -
  • Cryosat-2: -
  • HaiYang-2A/B : NSOAS
 
Retracking
 
  • Topex/Poseidon :  MLE3
  • Jason-1/2/3 : MLE4
  • ERS-1/2 : OPR
  • Envisat : MLE3 (OCE1)
  • SARAL-DP/AltiKa: MLE4
  • Sentinel-6A : Numerical LRM
  • Sentinel-3A/B : SAMOSA
  • Geosat Follow On : GFO retracker
  • Cryosat-2: SAMOSA 2.3
  • HaiYang-2A/B : MLE4
 
Orbit
 
  • Topex/Poseidon :  GSFC STD18
  • Jason-1: POE-E before 2023/06/07; POE-F after
Jason-2/3 : POE-F
  • ERS-1/2 : Reaper
  • Envisat : POE-E
  • SARAL-DP/AltiKa: POE-F
  • Sentinel-3A/B, Sentinel-6A : POE-F
  • Geosat Follow On : GSFC
  • Cryosat-2: POE-F
  • HaiYang-2A : POE-D
  • HaiYang-2B : POE-F

Environemental corrections

 
Sea State Bias
 
  • Topex/Poseidon :  2D Non parametric (Tran et al., 2010) on Topex; BM4 on Poseidon 
  • Cryosat-2: 2D Non parametric (baseline C) (Tran, 2018)
  • HaiYang-2B:  From L2 product
 
High Frequency Adjustment 
 
All missions : none
 
Ionospheric
 
  • Topex/Poseidon :  Filtered dual-frequency altimeter range measurements  (Ablain and Legeais, 2010) on Topex ; DORIS on Poseidon
  • Jason-1/2 : Filtered dual-frequency altimeter range measurements (Ablain et al., 2010) (from SSB C-band
  • Sentinel-6A : Filtered dual-frequency altimeter range from L2
  • Sentinel-3A/B : Filtered dual-frequency altimeter range from L2
 
Dry troposphere
 
All missions: ERA5 (1-hour) model based
 
Wet troposphere
 
  • Jason-1: JMR (FCDR) radiometer 
  • Jason-2/3: AMR radiometer
  • Envisat : MWR radiometer reprocessed
  • SARAL-DP/AltiKa: Neuronal Network (5 entries) V4
  • Sentinel-6A: AMR radiometer
  • Sentinel-3A/B : MWR3 radiometer
  • Geosat Follow On : GFO Radiometer and ECMWF model
  • HaiYang-2A/B: ECMWF model

Geophysical corrections

 
DAC
 
All missions: Before 2016/02: TUGO High frequencies forced with analysed ERA 5 pressure and wind field + inverse barometer Low fraquencies; 
Between 2016/02 and 2023/06/07: MOG2D HF forced with analysed ECMWF pressure and wind field (Carrère and Lyard, 2003) (operational version 3.2.0) + inverse barometer  LF; 
After 2023/06/07: TUGO High frequencies forced with analysed ECMWF pressure and wind field + inverse barometer  LF

Ocean tide
 
All missions: FES14b (Loren Carrère et al., 2016) before 2023/06/07 ; FES22b (Carrère et al., 2023) after
 
Internal tide
 
All missions: (Zaron, 2019) (HRETv8.1 tidal frequencies: M2, K1, S2, O1)
 
Pole tide
 
All missions: (Desai et al., 2015); Mean Pole Location 2017 (Ries and Desai, 2017)
 
Solid earth tide
 
All missions: Elastic response to tidal potential (Cartwright and Edden, 1973; Cartwright and Tayler, 1971)
 
Loading tide
 
All missions: FES2014 (Carrere et al., 2016)
 
GIA
 
All missions: The DUACS products are not corrected from Glacial Isostatic Adjustment (GIA) effects

Reference surfaces

 
Mean Profile/ Mean Sea Surface
 
  • Topex/Poseidon , Jason-1/2/3 repetitive phase: MP computed with Topex/Poseidon [January 1993, April 2002; cycles 11 to 353], Jason-1 [April 2002, October 2008; cycles 10 to 249]; Jason-2 [October 2008, May 2016; cycles 10 to 290] and Jason-3 [May 2016, March 2020; cycles 11 to 150] measurements. Referenced to the [1993, 2012] period.
Topex/Poseidon , Jason-1/2 interleaved phase: MP computed with Topex/Poseidon interleaved [September 2002, October 2005; cycles 368 to 481] and Jason-1 interleaved [February 2009, March 2012; cycles 262 to 374], Jason-2 interleaved [October-2016; March-2017; cycles 305 to 322]. measurements. Referenced to the [1993, 2012] period.
Jason-1/2 LRO phase : Hybrid MSS (SIO,CNES/CLS15,DTU15)
  • ERS-1/2: MP computed with ERS-2 [May 1995, January 2000; cycles 1 to 49], Envisat [May 2002, October 2010; cycles 6 to 94] and SARAL/Altika [Mars 2013, Mars 2015; cycles 1 to 22] measurements. Referenced to the 1993-2012 period.
  • Envisat, SARAL-DP/AltiKa repetitive phase: MP computed with computed with ERS-2 [May 1995, January 2000; cycles 1 to 49], Envisat [May 2002, October 2010; cycles 6 to 94] and SARAL/Altika [Mars 2013, Mars 2015; cycles 1 to 22] measurements. Referenced to the 1993-2012 period. 
Envisat, SARAL-DP/AltiKa geodetic phase: Hybrid MSS (SIO,CNES/CLS15,DTU15)
  • Sentinel-3A: MP computed with Sentinel-3A [March 2016, August 2020; cycles 1 to 61. Referenced to the 1993-2012 period
Sentinel-3B: Hybrid MSS (SIO,CNES/CLS15,DTU15)
  • Geosat Follow On: MP computed with Geosat Follow On [January 2000, September 2008; cycles 37 to 222] measurements. Referenced to the [1993, 2012] period.
Cryosat-2, HaiYang-2A/B, SWOT-nadir: Hybrid MSS (SIO,CNES/CLS15,DTU15)
 
Mean Dynamic Topography
 
All missions: Global: MDT_CNES_CLS18 (Mulet et al., 2021) merged with regional MDT CMEMS_2020 Mediterranean and Black Sea (Jousset et al., 2022; Jousset and Mulet, 2020)