Elevated humidity in the stratosphere as a gain factor of ozone depletion in Arctic according to Aura MLS observations
O.E. Bazhenov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: стратосфера, температура, влажность, озон, спутниковые данные, аномальные изменения, stratosphere, temperature, humidity, ozone, satellite data, anomalous variations
Abstract
Analysis of Aura MLS data showed that the temperature in the stratosphere of Arctic was much lower than normal during the entire period of January-March 2011 in the altitude range 20-35 km. This had led to a considerable spread of polar stratospheric clouds (PSCs) that formed most intensely in periods and at altitudes of minimal temperatures (maximal temperature drops below PSC formation threshold). The main ozone losses were observed in March. They were due to a photochemical release of chlorine that avoided deactivation in view of nitrogen deficit caused by denitrification in the course of frequent dehydration events indicated by oscillations of the altitude of maximal humidity deviation from multiyear norm. Elevated humidity in the stratosphere had increased the threshold temperature of formation of PSCs that persisted until late March; this raised the threshold of chlorine activation and, thereby, delayed the chlorine deactivation, resulting in even higher level of overall ozone losses during March 2011.
|
