References of "Meftah, M"
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See detailThe Sun-earth Imbalance radiometer for a direct measurement of the net heating of the Earth
Dewitte, S; Chevalier, A; Meftah, M et al

Conference (2012)

Although it is generally accepted that the climate on earth is changing due to a radiative energy imbalance at the top of the atmosphere, up to now this radiation imbalance has not been measured directly ... [more ▼]

Although it is generally accepted that the climate on earth is changing due to a radiative energy imbalance at the top of the atmosphere, up to now this radiation imbalance has not been measured directly. The measurement is challenging both in terms of space-time sampling of the radiative energy that is leaving the earth and in terms of accuracy. The incoming solar radiation and the outgoing terrestrial radiation are of nearly equal magnitude – of the order of 340 W/m² – resulting in a much smaller difference or imbalance of the order of 1 W/m². The only way to measure the imbalance with sufficient accuracy is to measure both the incoming solar and the outgoing terrestrial radiation with the same instrument. By reanalyzing data from the NASA LARC Earth Radiation Budget Experiment, we have been able to demonstrate that the sampling problem can be overcome, even with the low resolution Wide Field of View radiometer. We have combined the measurements of the precessing ERBS satellite for midlatitude and equatorial regions with measurements of the sun synchronuous NOAA9 satellite for the polar regions. For the accuracy requirement an improved instrument design is needed. We propose a new instrument, which we call the Sun-earth IMBAlance (SIMBA) radiometer. It is an improved wide field of view cavity radiometer based on our long experience with the DIARAD type of instrument for the measurement of Total Solar Irradiance. Currently we have two DIARAD instruments in space, on SOHO and on the ISS, and a third one will be launched this year on the Picard microsatellite. In this paper, we will present the ERBE sampling study and the SIMBA instrument and nanosatellite design [less ▲]

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See detailDYNAMO: a Mars upper atmosphere package for investigating solar wind interaction and escape processes, and mapping Martian fields
Chassefière, E.; Nagy, A.; Mandea, M. et al

in Advances in Space Research (2004), 33

DYNAMO is a small multi-instrument payload aimed at characterizing current atmospheric escape, which is still poorly constrained, and improving gravity and magnetic field representations, in order to ... [more ▼]

DYNAMO is a small multi-instrument payload aimed at characterizing current atmospheric escape, which is still poorly constrained, and improving gravity and magnetic field representations, in order to better understand the magnetic, geologic and thermal history of Mars. The internal structure and evolution of Mars is thought to have influenced climate evolution. The collapse of the primitive magnetosphere early in Mars history could have enhanced atmospheric escape and favored transition to the present arid climate. These objectives are achieved by using a low periapsis orbit. DYNAMO has been proposed in response to the AO released in February 2002 for instruments to be flown as a complementary payload onboard the CNES Orbiter to Mars (MO-07), foreseen to be launched in 2007 in the framework of the French PREMIER Mars exploration program. MO-07 orbital phase 2b (with an elliptical orbit of periapsis 170 km), and in a lesser extent 2a, offers an unprecedented opportunity to investigate by in situ probing the chemical and dynamical properties of the deep ionosphere, thermosphere, and the interaction between the atmosphere and the solar wind, and therefore the present atmospheric escape rate. Ultraviolet remote sensing is an essential complement to characterize high, tenuous, layers of the atmosphere. One Martian year of operation, with about 5,000 low passes, should allow DYNAMO to map in great detail the residual magnetic field, together with the gravity field. Additional data on the internal structure will be obtained by mapping the electric conductivity, sinergistically with the NETLANDER magnetic data. Three options have been recommended by the International Science and Technical Review Board (ISTRB), who met on July 1st and 2nd, 2002. One of them is centered on DYNAMO. The final choice, which should be made before the end of 2002, will depend on available funding resources at CNES. [less ▲]

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