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An entropy‐based measure of mixing at the tropopause
Author(s) -
Patmore N.,
Toumi R.
Publication year - 2006
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1256/qj.05.84
Subject(s) - tropopause , climatology , mixing (physics) , atmospheric sciences , convection , entropy (arrow of time) , convective mixing , meteorology , geology , environmental science , statistical physics , physics , troposphere , thermodynamics , quantum mechanics
Qualitative analysis of tracer correlations is now a well established technique for investigating mixing in the tropopause transition layer. Generally, these studies rely on in situ data retrieved over short distances and time‐scales. Using satellite data from HALOE, we introduce a simple quantitative analysis technique, based on entropy, to provide a climatology of mixing, from H 2 O:O 3 tracer correlations. Results compare well with previous studies using Lagrangian‐based estimates of effective diffusivity and equivalent lengths and also climatologies of tropopause folding. Further analysis techniques reveal characteristics of the transition layer, including its depth and position, leading to the distinction of three primary forms of mixing. Within our analysis domain, we estimate that half of total entropy can be attributed to subtropical ‘Rossby‐driven’ tropopause folding events. The majority of the remaining entropy is associated with tropical convective mixing and a third form, possibly linked to shear‐induced mixing at subtropical jet streaks. Copyright © 2006 Royal Meteorological Society