Zonal asymmetries in middle atmospheric ozone and water vapour derived from Odin satellite data 2001–2010

A Gabriel,S Lossow,H Körnich,J Urban,D H W Peters,D Murtagh

doi:10.5194/acp-11-9865-2011

Abstract

Abstract. Stationary wave patterns in middle atmospheric ozone (O3) and water vapour (H2O) are an important factor in the atmospheric circulation, but there is a strong gap in diagnosing and understanding their configuration and origin. Based on Odin satellite data from 2001 to 2010 we investigate the stationary wave patterns in O3 and H2O as indicated by the seasonal long-term means of the zonally asymmetric components O3* = O3-[O3] and H2O* = H2O-[H2O] ([O3], [H2O]: zonal means). At mid- and polar latitudes we find a pronounced wave one pattern in both constituents. In the Northern Hemisphere, the wave patterns increase during autumn, maintain their strength during winter and decay during spring, with maximum amplitudes of about 10–20 % of the zonal mean values. During winter, the wave one in O3* shows a maximum over the North Pacific/Aleutians and a minimum over the North Atlantic/Northern Europe and a double-peak structure with enhanced amplitude in the lower and in the upper stratosphere. The wave one in H2O* extends from the lower stratosphere to the upper mesosphere with a westward shift in phase with increasing height including a jump in phase at upper stratosphere altitudes. In the Southern Hemisphere, similar wave patterns occur mainly during southern spring. By comparing the observed wave patterns in O3* and H2O* with a linear solution of a steady-state transport equation for a zonally asymmetric tracer component we find that these wave patterns are primarily due to zonally asymmetric transport by geostrophically balanced winds, which are derived from observed temperature profiles. In addition temperature-dependent photochemistry contributes substantially to the spatial structure of the wave pattern in O3* . Further influences, e.g., zonal asymmetries in eddy mixing processes, are discussed.

Highlights

During recent years several investigations have been carried out to examine the possible influence of stationary wave patterns in stratospheric ozone (O3) on the atmospheric circulation, based on general circulation model studies with assimilated ozone data and with interactive chemistry (Kirchner and Peters, 2003; Sassi et al, 2005; Gabriel et al, 2007; Crook et al, 2008; Gillett et al, 2009; Waugh et al, 2009)
3 southern spring (SON), which indicate strong zonal asymmetrie4s in rmefeerridtioonmalintirmacuemr tnraengsaptoivrte. vTahlueessim).ilarity itnernphmasigehot 5fbethdeuneotrothseirmnilaanridtieths einsopulathneertnaryw-sacvaeleonoerogpraat-phy or due to similarities in the differences in tropospheric wave activity over the Pacific and over the Atlantic/Indian ocean basins
Pattern. we find a better agreement between the spatial structure of H2O∗(TR) and ppmv

Summary

Introduction

During recent years several investigations have been carried out to examine the possible influence of stationary wave patterns in stratospheric ozone (O3) on the atmospheric circulation, based on general circulation model studies with assimilated ozone data and with interactive chemistry (Kirchner and Peters, 2003; Sassi et al, 2005; Gabriel et al, 2007; Crook et al, 2008; Gillett et al, 2009; Waugh et al, 2009). The Odin satellite, which was launched in 2001 and which is currently still operational, provides such suitable information throughout the middle atmosphere (Urban et al, 2007, Lossow et al, 2008, 2009; Jones et al, 2009) We use this data to derive long-term means of quasi-stationary wave patterns in stratospheric ozone and stratospheric and mesospheric water vapour, as indicated by the zonal asymmetries O∗3 = O3-[O3] and H2O∗ = H2O-[H2O] ([O3], [H2O]: zonal means). In the Northern Hemisphere, H2O∗ shows a proshown by Fig. 1.1b), as usually found in other quantities like nounced wave one pattern during autumn and winter in the temperature or geopotential height, can be interpreted as a mesosphere up to an altitude of about 80 km and with a combination of transport processes in the lower and middle strong jump in phase at upper stratosphere altitudes, i.e. at stratosphere (where the chemical lifetime of ozone is long about 40–45 km (Fig. 2.1). The processes determining the stationary wave patterns in O∗3 and H2O∗ when analyzing the effects of the stationary quasigeostrophically-balanced flow on O∗3 and H2O∗

Transport tendencies and linear chemical loss rates

Contribution of the individual tendencies to the stationary wave patterns

Findings

Conclusions