Mobile version

ERS-1 and Topex/Poseidon wave heights and backscattering coefficients compare well

Pierre Queffeulou (Ifremer, France)

From September 23 to December 1, 1992, we did a comparative study of Topex/Poseidon and ERS-1 data. The Topex/Poseidon data was the first nine cycles over the Atlantic, (70°N-70°S, 100°W-30°E).

The IGDR-M, version 1, Topex/Poseidon data was supplied as simplified files by the Cnes Aviso/Altimetry team under the Quick-look project. The ERS-1 data was the Fast Delivery Products (FDPs) real-time data from the European Space Agency (ESA) and archived at Cersat. We chose points where the ground tracks of the two satellites crossed within one-hour intervals. The comparison data set consisted of the closest Topex/Poseidon and ERS-1 bins, each bin being a one-second average of the elementary Ku-band altimeter measurement by each satellite. The distance between bins was under 30 km for all the data, and under 5 km in 93% of cases. We selected 323 validated pairs: 32 Poseidon and 291 Topex.

The comparisons show that the two satellites' measurements correlate well, as illustrated in the graphs below, Topex on the left, Poseidon on the right.

For the backscattering coefficient, the mean differences are 0.07 dB between Topex and ERS-1 (rms deviation 0.32 dB) and 0.85 dB between Poseidon and ERS-1 (rms deviation 0.47 dB). This suggests a mean bias of 0.78 dB between Topex and Poseidon.

For the significant wave height, the calibration relationship derived during the RENE 91 validation experiment was applied to the ERS-1 FDP measurements (Hcorr = (HFDP - 0.37) / 0.84). The corrected ERS-1 and Topex/Poseidon measurements compare very well.

The mean differences are 0.02 m between Topex and ERS-1 (rms deviation 0.33 m) and 0.15 m between Poseidon and ERS-1 (rms deviation 0.35). These first results are generally satisfactory.

Rss feedsContactPartnersFAQLexiconLegal noticePersonal Data Protection PolicyMobile
You must enable cookies in your browser preferences to save the modifications
You are using an older version of Internet Explorer, please update to take full advantage of Aviso+ features

Customize the home page

View all widgets
Reduce display
Public profile
User profile

Select/Deselect widgets

Discover AVISO+

Customizable home, reading tools, products search guide, etc.. Discover step by step the features of the new site AVISO+.

Customizable homepage

This home page is composed of blocks called "widgets".

Rearrange the blocks with a "Click & Drop".

Hide a widget with the cross at the top right. Reset or add a widget with the "wrench" icon. The "User" and "Public" profiles offer a predefined organization.

All the modifications are automatically saved as cookies on your machine so as to enable you to have your own specific AVISO+.

Reading tools

Ease your reading by choosing the page background colour (black/white) and/or by modifying the font size.

Browsing menu and breadcrum trail

To ease your browsing through AVISO+, you can use at any time the main banner items with the interactive submenus or use the browsing menu on the left side of the screen (it is open by default). For more readiness of the page contents, you can fold and unfold the browsing menu by clicking on the tab. At any time you can know where you are thanks to the browsing menu or the breadcrum at the top of the page.

Products search guide

The first submenu of the "Data" banner item leads you to a new search form enabling you to find quickier the product that suits your needs. The list of results is updated according to your selection criteria.

AVISO+ Multimedia

The first submenu of the "Multimedia" banner item leads you to AVISO+ collections of images and videos linked to altimetry and its applications. Have a nice visit!