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Anomalously high levels of NO x in the polar upper stratosphere during April, 2004: Photochemical consistency of HALOE observations
Author(s) -
Natarajan Murali,
Remsberg Ellis E.,
Deaver Lance E.,
Russell James M.
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl020566
Subject(s) - stratosphere , occultation , atmospheric sciences , ozone , polar vortex , mixing ratio , polar , environmental science , potential vorticity , mesosphere , tropopause , middle latitudes , thermosphere , polar night , ozone depletion , stratopause , latitude , climatology , physics , vorticity , vortex , meteorology , geology , astrophysics , ionosphere , astronomy
Significant perturbations to the odd nitrogen mixing ratios in the high latitude upper stratosphere are seen in the Halogen Occultation Experiment (HALOE) data during April, 2004. Sunrise observation of 99.1 ppbv of NO x (NO + NO 2 ) at 68N represents the largest NO x measured near 2 hPa. Examination of potential vorticity maps indicates that these high NO x mixing ratios correspond to measurements made within the polar vortex. Photochemical model results show large reductions in ozone in response to the enhancements in NO x , and HALOE ozone data are in good agreement with the model results. Probable cause of these anomalous values of NO x in the upper stratosphere is the enhanced production of NO in the high latitude upper mesosphere/thermosphere regions due to the powerful solar flares and the associated energetic particle precipitation that took place during October–November, 2003, followed by downward transport in the polar winter.