The MIPAS HOCl climatology

Abstract

Monthly zonal mean HOCl measurements by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) are presented for the episode from June 2002 to March 2004. Highest molar mixing ratios are found at pressure levels between 6 and 2 hPa, whereby largest mixing ratios occasionally exceed 200 ppt. The mixing ratio maximum is generally at lower altitudes in the summer hemisphere than in the winter hemisphere except for chlorine activation conditions in polar vortices, where enhanced HOCl abundances are also found in the lower stratosphere. During nighttime the maximum is found at higher altitudes than during daytime. Particularly low values are found in subpolar regions in the winter hemisphere, coinciding with the mixing barrier formed by the polar vortex boundary. The Antarctic polar winter HOCl distribution in 2002, the year of the split of the southern polar vortex, resembles northern polar winters rather than other southern polar winters. Increased HOCl amounts in response to the so-called Halloween solar proton event in autumn 2003 affect the representativeness of data recorded during this particular episode. Calculations with the EMAC model reproduce the structure of the measured HOCl distribution but predict approximately 40 % less HOCl except during polar night in the mid-stratosphere where calculated HOCl mixing ratios exceed observed ones

SMILES zonal and diurnal variation climatology of stratospheric and mesospheric trace gasses: O3, HCl, HNO3, ClO, BrO, HOCl, HO2, and temperature

“…In order to be consistent with other middle atmospheric climatologies [ Jones et al , ; von Clarmann et al , ], we decided to use the Stratospheric Processes and their Role in Climate (SPARC)/Chemistry Climate Model Validation activity (CCMVal) vertical pressure grid [ SPARC Report No. 5 , ].…”

“…The formation of the nighttime reservoir is visible at all altitudes between 10hPa and 0.25hPa (30–60km) and its maximum abundance is found in higher altitudes than the daytime maximum, as suggested by von Clarmann et al . [].…”

“…The Envisat/MIPAS HOCl latitude climatology, described in von Clarmann et al [], proved to be difficult to compare with SMILES HOCl. The MIPAS averaging kernels are wider than SMILES‐averaging kernels and sometimes asymmetric.…”

“…A quite complete overview is given in the introduction of Jones et al []. In addition to that, there are a zonal HOCl climatology, derived from Envisat/Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) [ von Clarmann et al , ], and a nighttime O 3 climatology from the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument by Kyrölä et al [].…”

Effects of solar proton events on dayglow observed by the TIMED/SABER satellite

“…More recently, satellite observations used to investigate the responses of the middle atmosphere to the SPEs of solar cycles 23 and 24 include the Upper Atmosphere Research Satellite [ Kukoleva and Krivolutskii , ], Aura satellite [ Damiani et al , ; Päivärinta et al , ; Jackman et al , ], Odin satellite [ Degenstein et al , ], the Environmental Satellite (Envisat) [ von Clarmann et al , , ; Damiani et al , ; Friederich et al , ; Sinnhuber et al , ], and so on. In addition, models including the Whole Atmosphere Community Climate Model [ Damiani et al , ], the thermosphere‐ionosphere‐mesosphere‐electrodynamic general circulation model [ Jackman et al , ], the Sodankylä Ion and Neutral Chemistry model [ Verronen et al , , ; Verronen and Lehmann , ], and other models as described by Funke et al [] have been used to simulate the influences of the SPEs on the middle atmosphere.…”