Ozone Trends in the Upper Troposphere‐Lower Stratosphere Using Equivalent Latitude‐Potential Temperature Coordinates
Journal Article
Overview
abstract
Abstract; We analyze ozone trends in the upper troposphere and lower stratosphere (UTLS, 300–50 hPa), using geographical (latitude‐pressure and latitude‐altitude) and, for the first time, dynamical (equivalent latitude‐potential temperature, EqL‐) coordinates. Trends are determined using linear least squares fits, multiple linear regression, and dynamical linear modeling. Regardless of the method, EqL‐ improves consistency between trends across the UTLS, reduces large UT tropical uncertainties, alters the magnitude of mid‐latitude trends, and, most notably, in the Southern polar lower stratosphere, reveals statistically significant trends exceeding 8% per decade during Antarctic Spring. This provides further evidence of Antarctic ozone recovery. These robust trends are not captured using geographical coordinates. We argue that EqL‐ enables more physically grounded interpretations of chemical ozone trends and their uncertainties, as EqL‐ accounts for the adiabatic (reversible) transport of ozone.
