ADT-H - Absolute Dynamic Topography (along-track)
Types of dataset: Ssalto/Duacs along-track multimission altimeter products
Contents: along-track sea surface heights above geoid; dynamic topography is the sum of sea level anomaly (SLA) and mean dynamic topography (MDT), both being referenced over a twenty-year period in the Duacs 2014 version (V15.0). On this basis, the ADT is unchanged since the ADT products have been caluclated with consistent SLA and MDT field.
Use: study of the general circulation (ocean gyres ...)
Condition of access : All Ssalto/Duacs product users need an account on FTP, see Access to Ssalto/Duacs data
Data access service: Along-track products are only delivered through the authenticated FTP server.
Description: mono altimeter satellite product homogeneous with other satellites, available in near-real time and in delayed time.
Geographic coverage: global. A specific regional product with an improved quality is available in local areas (more information).
Description: this delayed time product is available in two series:
- "filtered" serie (vfec) : validated + filtered + subsampled + correction for LW (long wavelengh) errrors product. Residual noise and small scale signals are removed by filtering the data using a Lanczos filter. As data are filtered from small scales, a sub-sampling is finally applied. As a consequence, for a given date, the distance between each measurement is bigger in a "vfec" file than in the "vxxc" file. Note that the filtering and sub-sampling is adapted to each region and product as a function of the characteristics of the area and of the assimilation needs (see details in the handbook, section "Filtering and Sub-sampling" for Delayed-Time products). Users that need to use a measurement with noise error reduced should rather user this filtered product.
- "unfiltered" serie (vxxc): validated + non filtered + non subsampled + correction for LW errrors. This product keeps the full 1Hz resolution. This means that for a given date, the number of measurements is bigger in a "vxxc" file than in the vfec file. Moreover, the uncorrelated measurement noise is not reduced (because of non filtering). Users that need the full 1 Hz measurements should use this unfiltered product keeping in mind that it is affected by the full 1Hz measurement noise error.
Copyright : 1993-ongoing CLS - Cnes
|Access service||Frequency||Data period||File weight|
|3-4 months||From mars-13 to janv-16||700 Ko per file (zipped)|
|Cryosat-2||From Apr-12 to janv-16|
|Jason-2||From oct-08 to janv-16|
|Jason-1 (j1, j1g, j1n)||From Apr-02 to juin-13|
|Envisat (en, enn)||From oct-02 to Apr-12|
|ERS-1||From oct-92 to May-95|
|ERS-2||From May-95 to Apr-03|
|T/P(tp, tpn)||From sept-92 to oct-05|
Description : Only "filtered" version ("vfec", see description above) is delivered. FTP delivers daily the most recent data: the most recent file is updated several times per day in order to include the most recent available OGDR data.
Data period : within a few months at most, from the latest update of the DT products to today.
Copyright : 2004-ongoing CLS-Cnes.
||Frequency||Delivery delay||Data period||File weight|
|Jason-3||authenticated FTP: filtered||Daily||3 hours to 3 days||From sept-16 today||2.5 MB per file (zipped)|
|Saral||Daily||3 hours to 3 days||From janv-16 to today||350 Ko per file (zipped)|
|Cryosat-2||Daily||3 hours to 3 days (best effort)||From janv-16 to today||300 Ko per file (zipped)|
|Jason-2||Daily||3 hours to 3 days||From janv-16 to sept-16||2.5 MB per file (zipped)|