Alain Rosak

MEGHA - TROPIQUES satellite mission: In flight performances results

MEGHA-TROPIQUES is an CNES-ISRO collaborative satellite mission designed to study atmospheric water cycles and energy exchanges in the tropical belt. The satellite was launched successfully by ISRO in October 2011 from Sriharikota launch pad (India). The satellite is carrying 4 instruments · MADRAS Instrument : A conical scanning microwave imager designed to estimate precipitations and clouds properties. · SAPHIR Instrument : A microwave sensor used to retrieve vertical humidity profiles. · SCARAB Instrument : An wide band optical radiometer used to retrieve Earth Radiation budget parameters. · GPS-ROS instrument : The sensor will provide temperature and humidity profiles of the Earths atmosphere After 7 months of in orbit operation, this paper is presenting the measured in orbit performances of the French sensors or subsystems.

Radiometric and geometric scarab-megha-tropiques ground calibration comparison with first in orbit calibration

The Scarab-3 instrument, part of the Indian-French Megha-Tropiques mission [1], has been launched in october 2011. It is a radiometer dedicated to earth radiation budget. CNES is prime of the development of this instrument. Last year, CNES conducted the final integration of the instrument and the radiometric/geometric calibrations. Two main spectral bands are measured by this instrument: A shortwave (SW) channel dedicated to solar fluxes and a Total (T) channel for (total) fluxes combining the infra-red earth radiance and the albedo. The earth long wave (LW) radiance is computed by subtracting the SW channel to the Total channel. Thus is defined a 3rd (virtual) LW channel. To obtain a good radiometric accuracy, intensive tests have been conducted using integrating sphere, black body calibration, vacuum tests and collimator test. After a brief sum up of the instrument, the results of the calibration will be presented and compared with the first in orbit calibration.

ScaRaB: first results of the scanner for radiative budget on board the Indo-French satellite Megha-Tropiques

ScaRaB (SCAnner for RAdiation Budget) is the name of three radiometers whose two first flight models have been launched in 1994 and 1997. The instruments were mounted on-board Russian satellites, METEOR and RESURS. On October 12th, a last model has been launched from the Indian site of Sriharikota. ScaRaB is a passenger of MEGHATROPIQUES, an Indo-French joint Satellite Mission for studying the water cycle and energy exchanges in the tropics. The orbit is circular inclined 20deg. ScaRaB is compatible with CERES mission. Two main spectral bands are measured by the radiometer: A short-wave (SW) channel (0.2 – 4 μm) dedicated to solar fluxes and a Total (Tot) channel (0.2 – 200 μm) for (total) fluxes combining the infrared earth radiance and the albedo. The earth long-wave (LW) radiance is isolated by subtracting the SW channel to the Total channel. Thus is defined a supplemental (virtual) channel.

Static Infrared Fourier Transform Interferometer (SIFTI):Benefits of Phase Modulation Processing

SIFTI (Static Infrared Fourier Transform Interferometer) is a high resolution spectrometer, part of the TRAQ payload. This paper presents a description of this instrument and gives a preliminary radiometric performance in presence of phase modulation.

Progress in static fourier transform infrared spectroscopy: assessment of sifti preliminary performances

The concept of static Fourier transform interferometry at thermal infrared wavelengths is well suited in the case of narrow spectral bands that are looked at for targeted molecular species as CO and O3 for pollution and air quality monitoring, or H20 and CO2 for weather forecast, down to the troposphere. It permits a high spectral resolution and a very good radiometric performance, with the advantage of a static interferometer, including no moving part. Along with other molecules sounded in the UV-VIS domain, as for instance in the TRAQ mission, SIFTI will provide scientists with a complete set for pollution measurements and air quality survey. Our paper presents the principles of static Fourier transform spectrometry, the work led on the instrument performance model and our study of the SIFTI instrument. We describe the instrument, its main dimensions and characteristics, and its architecture and major subsystems. We eventually make a preliminary survey of the SIFTI performance budget items. As a conclusion, we introduce the future CNES phase A study of this instrument that is started in 2006