Etude et réalisation d'un simulateur de réactivité et son application à la simulation d'un réacteur nucléaire pilote

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Determination of Tropical Radiation Budget At High Time and Space Resolution By Combination of Geostationary and Polar Satellite Measurements.

ERB(Earth Radiation Budget) data describe how the earth gains engergy, due to absorbed solar radiation flux, or looses energy, due to emitted thermal radiation flux. Since the atmospheric energetics is described by differential equations with derivatives in space and in time, high resolution spatial and temporal ERB data should be available. ERB data derived from satellite measurements exist (ERBE(Earth Radiation Budget Experiment) [8] , ScaRaB(Scanning radiometer for Radiation Budget measurements) [9], planned: CERES(Cloud and the Earth's Radiant Energy System)) but the space/time resolution of these data is insufficient to use them directly as input to atmospheric models. The purpose of this work is to combine these data with the high space/time resolution images of geostationary meteorological satellites (such as METEOSAT or the future MSG(Meteosat Second Genereation) carrying SEVIRI(Spinning Enhanced Visible and Infrared Imager) and GERB(Geostationary Earth Radiation Budget)), in o..

SOVAP/Picard, a spaceborne radiometer to measure the Total Solar Irradiance

International audienceThe Picard spacecraft was successfully launched on June 15, 2010, into a Sun synchronous orbit. The mission represents one of the European contributions to solar observations and Essential Climate Variables (ECVs) measurements. The payload is composed of a Solar Diameter Imager and Surface Mapper (SODISM) and two radiometers: SOlar VAriability Picard (SOVAP) and PREcision MOnitor Sensor (PREMOS). SOVAP, a dual side-by-side cavity radiometer, measures the total solar irradiance (TSI). It is the sixth of a series of differential absolute radiometer type instruments developed and operated in space by the Royal Meteorological Institute of Belgium. The measurements of SOVAP in the summer of 2010, yielded a TSI value of 1362.1 W.m−2 with an uncertainty of ±2.4W.m−2 (k=1). During the periods of November 2010 and January 2013, the amplitude of the changes in TSI has been of the order of 0.18%, corresponding to a range of about 2.4W.m−2

Picard: solar diameter, irradiance and climate

ABSTRACT The PICARD microsatellite mission will provide 3 to 4 years simultaneous measurements of the solar diameter, differential rotation and solar constant to investigate the nature of their relations and variabilities. The 110 kg satellite has a 42 kg payload consisting of 3 instruments: SODISM, which will deliver an absolute measure (better than 4 milliarcsec) of the solar diameter and solar shape, SOVAP, measuring the total solar irradiance, and PREMOS, dedicated to the UV and visible flux in selected wavelength bands. Now in Phase B, PICARD is expected to be launched by 2005. We review the scientific goals linked to the diameter measurement with interest for Earth Climate, Space Weather and Helioseismology, present the payload and instruments' concepts and design, and give a brief overview of the program aspects

On-orbit degradation of solar instrument

We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing space missions