Virolainen, Y.A., Timofeyev, Y.M., Polyakov, A.V., Poberovsky A.V. Ground-Based FTIR Measurements of Atmospheric Nitric Acid at the NDACC St. Petersburg Site. Izv. Atmos. Ocean. Phys. 59, 167–173 (2023). https://doi.org/10.1134/S000143382302007X
Abstract
Atmospheric nitric acid (HNO3) has a significant impact on the formation of the ozone layer; therefore, its content is regularly monitored using various local and remote-sensing methods. We use ground-based measurements of solar IR spectra with a Bruker 125HR Fourier spectrometer to derive information on the HNO3 content at the NDACC St. Petersburg observational site in Peterhof. The HNO3 time series shows a pronounced seasonal cycle with a maximum in winter and early spring and a minimum in summer and early autumn.
The averaged seasonal variations in nitric acid vary from –30 to +60% for the 0–15 km layer, from –25 to +25% for the 15–50 km layer, and from –25 to +30% for total columns. For the 2009–2022 measurement period, no statistically significant trend is found in the time series considered. A comparison of HNO3 stratospheric columns with independent satellite measurements by the MLS and ACE–FTS instruments shows their qualitative and quantitative agreement; the correlation coefficient between ground-based and satellite measurements totals 0.88–0.93.
Time series on the vertical structure of the atmospheric nitric acid measured at the St. Petersburg site can be used both to analyze the state of the ozonosphere and to validate satellite measurements and refine the parameters of atmospheric models.