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aries1988 : atmosphere   6

Comment le Sahara nourrit la Méditerranée
« A chaque arrêt, l’eau sera récupérée et mise dans des mésocosmes [réservoirs recréant les conditions d’un milieu naturel]. On augmentera la température de 2 degrés ainsi que la teneur en CO2 pour voir comment le phytoplancton réagit. De cette manière, nous recréons les conditions que nous aurons en 2100 », résume Karine ­Desboeufs. Malgré un appui ­météo au sol, le Pourquoi-Pas ? n’a aucune garantie de croiser la route d’une pluie de poussières sahariennes. En cas de malchance, la campagne ne sera pas vaine pour autant. Des appareils de ­mesure enregistreront simultanément les paramètres chimiques, physiques et biologiques de l’air et des eaux de surface. La comparaison des données permettra de ­rechercher les interactions.
mediterranean  europe  research  science  atmosphere  sea  biology 
may 2017 by aries1988
Atmospheric Aerosols: What Are They, and Why Are They So Important? | NASA
Aerosols interact both directly and indirectly with the Earth's radiation budget and climate. As a direct effect, the aerosols scatter sunlight directly back into space. As an indirect effect, aerosols in the lower atmosphere can modify the size of cloud particles, changing how the clouds reflect and absorb sunlight, thereby affecting the Earth's energy budget.

Aerosols also can act as sites for chemical reactions to take place (heterogeneous chemistry). The most significant of these reactions are those that lead to the destruction of stratospheric ozone. During winter in the polar regions, aerosols grow to form polar stratospheric clouds. The large surface areas of these cloud particles provide sites for chemical reactions to take place. These reactions lead to the formation of large amounts of reactive chlorine and, ultimately, to the destruction of ozone in the stratosphere. Evidence now exists that shows similar changes in stratospheric ozone concentrations occur after major volcanic eruptions, like Mt. Pinatubo in 1991, where tons of volcanic aerosols are blown into the atmosphere (Fig. 1).
explained  atmosphere 
december 2015 by aries1988

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