4D-VAR Chemical Data Assimilation
displays the daily variation of the Nitric Acid Trihydrate (NAT) over
the Arctic. The time window spans over 15 days.
investigation of polar stratospheric clouds carried out by scientists of
the Max-Planck-Institut fur Kernphysik, Division of Atmospheric Physics,
Germany, highlights that particle composition analysis of cloud layers
over the polar regions. It showed that a large fraction of the layers was
composed of nitric acid trihydrate (NAT) particles, containing water and
nitric acid at a molar ratio of 3:1. This finding is of particular
importance for climate monitoring, since the presence of NAT particles
enhances the potential for chlorine activation with subsequent ozone
destruction, particularly in early and late winter. Click
here for abstract.
The model used in this application is based
on 475K, which corresponds to an isentropic level in the lower
stratosphere, close to 60 hPa pressure or 20 km altitude.
Bascoe (Belgian Assimilation
System of Chemical Observations from ENVISAT)
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,