Equatorial Kelvin wave signatures in ozone profile measurements from Global Ozone Monitoring Experiment (GOME)

Abstract

This study investigates the ability to derive height‐resolved information on equatorial Kelvin wave activity from three different Global Ozone Monitoring Experiment (GOME) ozone profile data sets. The ozone profiles derived using the Ozone Profile Retrieval Algorithm (OPERA) based on optimal estimation and the Neural Network Ozone Retrieval System (NNORSY) both show Kelvin wave signals in agreement with previously identified signals in the GOME total ozone columns. However, because of the inadequate vertical resolution, these two data sets are not able to resolve the vertical structure of the Kelvin wave activity. The third data set, consisting of assimilated OPERA ozone profiles, does provide height‐resolved information on Kelvin wave activity that is consistent with results from the analysis of GOME total ozone columns and ECMWF Re‐Analysis (ERA‐40) temperature data. Largest Kelvin‐wave‐induced perturbations of up to 0.69 DU/km coincide with the maximum vertical gradient in ozone around 35 hPa and show an in‐phase relationship with temperature perturbations in ERA‐40 as expected from theoretical considerations. These results indicate that the ozone perturbations in the lower stratosphere and in the total column of ozone are transport related. Between 10 and 1 hPa, large Kelvin‐wave‐induced fluctuations in ozone mixing ratio are present that, however, because of their small contribution to the total column, do not constitute a large contribution to the total ozone column perturbations. The ozone perturbations between 10 and 1 hPa show an out‐of‐phase relationship with temperature perturbations in ERA‐40, indicating that the perturbations can either be caused by transport effects or photochemical influences.