Ground-based measurements of HF total column abundances in the stratosphere near St. Petersburg (2009–2013)

Abstract

An analysis of ground-based spectroscopic measurements of hydrogen fluoride total column abundances (HF TCAs) near St. Petersburg for a 4-year period (2009–2013) is performed. The average HF TCA is 1.93 × 1015 cm−2, and the RMS variation (natural variability) for the measurement ensemble is about 20%. The data are in good agreement with measurements collected at the NDACC stations (Bremen and Harestua), taking into account the differences in latitude. The monthly average HF TCAs show seasonal variation with peaks in late winter and early spring and troughs in the period from November to January. The variability of the monthly averages is at a maximum in winter and spring. A comparison of the HF TCAs from ground-based measurements with those from ACE-FTS solar occultation measurements shows that the total abundances from the ground-based data are 12% lower than those from the ACE-FTS data, and the RMS differences depend on the version of the satellite data processing system, being 13 and 16% for versions 2.2 and 3.0, respectively. The calculated ratio between HCl and HF total column abundances is significantly lower in late winter and spring. The linear trend of this ratio is 2.5% per year. Although the trend statistics is insufficient due to the short observation period, the pattern is explained both by the decrease in the stratospheric HCl content and the small increase in HF TCAs over the studied period and is consistent with literature data.