Altimeter standards

Retracking

• Topex/Poseidon :  Topoex: Tracker; Poseidob: MLE3

• Jason-1/2/3 : MLE4 (Amarouche et al, 2004)

• ERS-1/2 : MLE3

• Envisat : MLE3 (OCE1)

• SARAL-DP/AltiKa: MLE4 (Amarouche et al, 2004)

• Sentinel-3A/B : SAMOSA 2.3 (ESRIN, 2015) up to December 2017; SAMOSA2.5 after

• Geosat Follow On : MLE3

• Cryosat-2: Before Jan 2016MLE4 on LRM mode area (Amarouche et al, 2004); Tracker on SAR mode areas (Boy et al, 2017);Form Jan 2016 to Nov 2017: MLE4 on LRM mode area. After Nov 2017: MLE4 on LRM mode area SAMOSA2.3 (Cotton et al, 2016) on SAR and SARin mode areas

• HaiYang-2A : MLE4

Orbit

• Topex/Poseidon :  GSFC STD15 until c365, STD12 afterwards

• Jason-1/2 : POE-E

• Jason-3: POE-E before Cycle 95; GDR-F after

• ERS-1/2 : Reaper (Rudenko et al, 2012)

• Envisat : POE-D

• SARAL[-DP]/AltiKa: POE-D

• Sentinel-3A: POE-E

• Geosat Follow On : GSFC

• Cryosat-2: POE-E

• HaiYang-2A : POE-E

Environemental corrections

Sea State Bias

• Topex/Poseidon :  Non parametric SSB (Tran et al, 2010) (using cyc 1 to 11 with GDR-C standards and GDR-D orbit)

• Jason-1: SSB issued from GDR-E

• Jason-2/3: Non parametric (Tran et al., 2012)

• ERS-1: BM3 (Gaspar and Ogor, 1994)

• ERS-2: Non parametric (Mertz et al., 2005) using cyc 70 to 80 with DELFT orbit nd equivalent of GDR-B standards

• Envisat : 2D non parametric (Tran, 2015)

• SARAL-DP/AltiKa: non parametric from J1 (Tran, 2014)

• Sentinel-3A : Non parametric (Tran,et al 2012)

• Geosat Follow On : Non parametric from J1  (Tran et al., 2010)

• Cryosat-2: 2D Non parametric SSB from J1 with unbiased sigma0

• HaiYang-2A: Non parametruc from J1

High Frequency Adjustment 

All missions : none

Ionospheric

• Topex/Poseidon :  Filtered dual-frequency altimeter range measurements (Topex) (Guibbaud et al., 2015); Doris (Poseidon)

• Jason-1 : Filtered dual-frequency altimeter range measurements (Guibbaud et al., 2015)

• Jason2 : Filtered dual-frequency altimeter range  (Guibbaud et al., 2015) (from SSB C-band)

• Jason-3 : Filtered dual-frequency altimeter range measurements (Guibbaud et al., 2015)

• ERS-1 : - Reaper NIC09 model (Scharroo and Smith, 2010)

• ERS-2  : NIC09 model (Scharroo and Smith, 2010) for cyc <=36; GIM (Iijima et al., 1999) after

• Envisat : Dual-frequency altimeter range measurement (Guibbaud et al., 2015) for c<=65;  GIM (Iijima et al., 1999) corrected for 8mm bias after

• SARAL[-DP]/AltiKa : GIM (Iijima et al., 1999)

• Sentinel-3A : Filtered dual-frequency altimeter range (Guibbaud et al., 2015)

• Geosat Follow On : GIM (Iijima et al., 1999)

• Cryosat-2: GIM (Iijima et al., 1999)

• HaiYang-2A: GIM (Iijima et al., 1999)

Dry troposphere

• Topex/Poseidon :  Model based on ERA-INTERIM

• Jason-1/2/3 : Model based on ECMWF rectangular grid

• ERS-1/2 : - Model based on ERA-INTERIM

• Envisat : Model based on ECMWF Gaussian grids

• SARAL[-DP]/AltiKa : Model based on ECMWF Gaussian grids

• Sentinel-3A : Model based on ECMWF Gaussian grids

• Geosat Follow On : Model based on ECMWF rectangular grid

• Cryosat-2: Model based on ECMWF Gaussian grids

• HaiYang-2A: Model based on ECMWF Gaussian grids

Wet troposphere

• Topex/Poseidon :  GNSS derived Path Delay (Fernandes et al., 2015)

• Jason-1: JMR (GDR-E) radiometer

• Jason-2: Neural Network correction (Keihm, 1995)
  Jason-3: AMR radiometer

• ERS-1/2 : GNSS derived Path Delay (Fernandes et al., 2015)

• Envisat : Neural Network (5 entries) (Obligis et al, 2009; Picard et al, 2015)

• SARAL[-DP]/AltiKa: Neural Network (5 entries) (Obligis et al, 2009; Picard et al, 2015)

• Sentinel-3A : from AMR radiometer

• Geosat Follow On : from GFO Radiometer

• Cryosat-2: ECMWF model

• HaiYang-2A: ECMWF model

Geophysical corrections

DAC

Topex/Poseidon : MOG2D High frequencies forced with analysed ERA-INTERIM pressure and wind field + inverse barometer Low Frequencies
ERS-1/2 : MOG2D High frequencies forced with analysed ERA-INTERIM pressure and wind field + inverse barometer Low Frequencies
All other missions: MOG2D High frequencies forced with analysed ECMWF pressure and wind field [Carrere and Lyard, 2003; operational version used, current version is 3.2.0] + inverse barometer Low Frequencies

Ocean tide

All missions: FES2014 (Carrère et al., 2015)

Internal tide

All missions: none

Pole tide

All missions: (Desai et al., 2015)

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] and Jason-2 [October 2008, December 2015; cycles 10 to 273] measurements. Referenced to the [1993, 2012] period (Taburet et al, 2019).
  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] measurements. Referenced to the [1993, 2012] period (Taburet et al, 2019).
  Jason-1/2 LRO phase : MSS CNES_CLS_2015 referenced to the 1993-2012 period (Pujol et al, 2016)

• ERS-1/2: MP computed with ERS-2 [May 1995, January 2000; cycles 1 to 49], Envisat [October 2002, October 2010; cycles 10 to 94] and SARAL/Altika [Mars 2013, Mars 2015; cycles 1 to 22] measurements. Referenced to the [1993, 2012] period (Taburet et al, 2019).

• Envisat, SARAL-DP/AltiKa: MP computed with ERS-2 [May 1995, January 2000; cycles 1 to 49], Envisat [October 2002, October 2010; cycles 10 to 94] and SARAL/Altika [Mars 2013, Mars 2015; cycles 1 to 22] measurements. Referenced to the [1993, 2012] period (Taburet et al, 2019). 
  Envisat, SARAL-DP/AltiKa geodetic phase: MSS CNES_CLS_2015 referenced to the 1993-2012 period (Pujol et al, 2016) for geodetic phase

• Sentinel-3A: MP computed with Sentinel-3A [June 2016, August 2018; cycles 5 to 34] (Dibarboure et Pujol, 2019)
  Sentinel-3B: MSS CNES_CLS_2015 referenced to the 1993-2012 period (Pujol et al, 2016)

• Geosat Follow On: MP computed with Geosat Follow On [January 2000, September 2008; cycles 37 to 222] measurements. Referenced to the [1993, 2012] period (Taburet et al, 2019).
  Cryosat-2, HaiYang-2A/B, SWOT-nadir: MSS CNES_CLS_2015 referenced to the 1993-2012 period (Pujol et al, 2016)

Mean Dynamic Topography

All missions: Global area: MDT_CNES_CLS13 (Mulet et al, 2013) corrected to be consistent with the 20-year reference period used for the SLA
Mediterranean Sea: SMDT_MED_2014 (Rio et al, 2014b) consistent with the 20-year reference period used for the SLA