Open AccessRole of NO y as a diagnostic of small‐scale mixing in a denitrified polar vortex
Author(s) -
Gao R. S.,
Popp P. J.,
Ray E. A.,
Rosenlof K. H.,
Northway M. J.,
Fahey D. W.,
Tuck A. F.,
Webster C. R.,
Hurst D. F.,
Schauffler S. M.,
Jost H.,
Bui T. P.
Publication year - 2002
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jd002332
Subject(s) - polar vortex , stratosphere , vortex , mixing (physics) , isentropic process , potential temperature , atmospheric sciences , mixing ratio , environmental science , physics , thermodynamics , quantum mechanics
Observations of three stratospheric species (N 2 O, CH 4 , and NO y ) are examined for their suitability as mixing tracers in the inner Arctic vortex region between late February and mid‐March 2000. NO y is highly inhomogeneous on isentropic surfaces and has little systematic vertical gradient between the 420 and 470 K potential temperature surfaces due to severe and extensive denitrification. Probability distribution functions of NO y calculated from in situ measurements do not show systematic and significant change as a function of time, indicating that mixing was too slow to substantially homogenize NO y distribution and therefore to strongly affect photochemical O 3 destruction rates during the period. We propose that the NO y inhomogeneity is useful for diagnosing small‐scale, irreversible mixing rates during the measurement period. A simple kinematic model is used to show that the NO y standard deviation on an isentropic level in the vortex has desirable properties for quantifying these rates. A practical method for deriving mixing rates for chemistry and transport models has been proposed for future studies.