On the spatiotemporal behavior of ozone within the upper mesosphere/mesopause region under nearly polar night conditions

Abstract

[1] The spatiotemporal behavior of the ozone mixing ratio in the upper mesosphere/ mesopause region under nearly polar night conditions is one of the phenomena not completely understood and reproduced by models thus far. We examine this issue using an advanced three-dimensional model of the dynamics and chemistry of the middle atmosphere (0-150 km) particularly designed to investigate the spatiotemporal structure of this phenomenon in the extended mesopause region. The most marked features of the modeling results are a pronounced ozone maximum around 72 km occurring close to the polar night terminator and a strong drop of the mixing ratio above $80 km. These features were also found by means of ground-based microwave measurements in high latitude at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR, 69.29°N, 16.03°E) and even at the moderate latitude of Lindau (51.66°N, 10.13°E) during the night in the winter season but less marked there. They were absent at both stations during the daytime hours. The calculations suggest that the stronger enhanced ozone values occur in a latitudinal band of approximately 15°in the vicinity of the polar night terminator. During nighttime, enhanced values reach into midlatitudes. The effect is confined both to a height interval approximately between 66 and 76 km and to a certain latitudinal range which alters with season according to the change of the polar night terminator. We discuss the model results in terms of chemistry for nearly grazing incidence conditions of the solar insolation and in context with advective transport.

Comparison of ozone profiles and influences from the tertiary ozone maximum in the night-to-day ratio above Switzerland

“…This maximum in mesospheric ozone during nighttime in winter is related to the middle-mesospheric maximum in ozone (MMM) (e.g. Sonnemann et al, 2007;Hartogh et al, 2004) also known as the tertiary ozone maximum (e.g. Sofieva et al, 2009;Degenstein et al, 2005;Marsh et al, 2001).…”

“…This results in higher ozone concentration because atomic oxygen recombination (Reaction R6) remains as a significant source of ozone in the mesosphere. Additionally, Hartogh et al (2004) extended the interpretation by considering the very slow decrease in the ozone dissociation (Reaction R7) rate with increasing solar zenith angle.…”

Daytime ozone loss term in the mesopause region

“…The CTM has been described in numerous papers (e.g., Sonnemann et al, 1998;Körner and Sonnemann, 2001;Grygalashvyly et al, 2009Grygalashvyly et al, , 2011Grygalashvyly et al, , 2012. It was validated, particularly for ozone, in a number of papers with measurements (Hartogh et al, 2004(Hartogh et al, , 2011Sonnemann et al, 2006aSonnemann et al, , b, 2007. Three-dimensional fields of the temperature and winds are used from the Canadian Middle Atmosphere Model (CMAM) for the year 2000 (de Grandpre et al, 2000;Scinocca et al, 2008).…”

Upper stratospheric ozone decrease events due to a positive feedback between ozone and the ozone dissociation rate

“…The chemical code including the chemical reaction rates are taken from our 3-D models (e.g. Sonnemann et al, 1998Sonnemann et al, , 2008Hartogh et al, 2004). The ClO x -mixing ratio was taken as constant for each model run but the partitioning between the share of Cl and ClO was variable depending on the odd oxygen chemistry.…”