Mobile version

Radiometry principle

Microwave remote sensing uses passive microwave radiometers. The microwaves have wavelength ranging from a few kHz to THz. The “passive” term means that it uses microwaves naturally radiated by the observed area (this is different from the radar principle where the sensor transmits a microwave signal towards a target and detects the backscattered radiation).

Radiometry principle

Satellite passive microwave radiometers measure raw antenna counts from which we determine the antenna temperature and then calculate the brightness temperature of the Earth.  Large antennas are used for the various channels of the radiometer, and in operation, each antenna feedhorn passes a hot and cold target in order to provide consistently calibrated raw counts.  Brightness temperature is a measure of the radiance of microwave radiation traveling upward from the top of Earth's atmosphere.  The conversion from radiometer counts to top-of-the-atmosphere (TOA) brightness temperature is called the calibration process. Several calibration processing steps are required to derive the brightness temperature values.

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!