Saturday, April 10, 2010

Metop-A measures global water vapour and formaldehyde

EUMETSAT: The Global Ozone Monitoring Experiment-2 (GOME-2), the scanning spectrometer on board EUMETSAT’s Metop-A polar-orbiting satellite, is now delivering operational information on the total amount of water vapour and formaldehyde.

Atmospheric water vapour (H2O) is the most important natural (as opposed to man-made) greenhouse gas, accounting for about two-thirds of the natural greenhouse effect. Despite this importance, its role in climate and its reaction to climate change are still difficult to assess. Many details of the hydrological cycle are poorly understood, such as the process of cloud formation and the transport and release of latent heat contained in the water vapour. In contrast to other important greenhouse gases like carbon dioxide (CO2) and methane, water vapour has a much higher temporal and spatial variability. Global monitoring of H2O by Metop-A is therefore a key to understanding its impact on climate.

Formaldehyde (HCHO) is one of the most abundant hydrocarbons in the atmosphere and is an important indicator of so-called non-methane volatile organic compound (NMVOC) emissions and photochemical activity. As such, it is an indicator of the presence of volatile organic compounds in the atmosphere, which in turn play an important role in the formation of toxic ozone close to the surface and also have an important influence on climate through the formation of large aerosol particles…

H2O total column distribution in March 2010 as measured by GOME-2/Metop-A. The global water vapour patterns over land and ocean are clearly visible with moist Intertropical Convergence Zone near the equatorial regions and dry polar regions.

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