Post‐Mount Pinatubo eruption ground‐based infrared stratospheric column measurements of HNO₃, NO, and NO₂ and their comparison with model calculations

Abstract

with the Fourier transform spectrometer on Kitt Peak (31.9°N latitude, 111.6°W longitude, 2.09 km altitude) have been analyzed to retrieve stratospheric columns of HNO 3 , NO, and NO 2 . The measurements cover a decade time span following the June 1991 Mount Pinatubo volcanic eruption and were recorded typically at 0.01 cm À1 spectral resolution. The measured HNO 3 stratospheric column shows a 20% decline from 9.16 Â 10 15 molecules cm À2 from the first observation in March 1992 to 7.40 Â 10 15 molecules cm À2 at the start of 1996 reaching a broad minimum of 6.95 Â 10 15 molecules cm À2 thereafter. Normalized daytime NO and NO 2 stratospheric column trends for the full post-Pinatubo eruption time period equal (+1.56 ± 0.45)% yr À1 , 1 sigma, and (+0.52 ± 0.32)% yr À1 , 1 sigma, respectively. The long-term trends are superimposed on seasonal cycles with $10% relative amplitudes with respect to mean values, winter maxima for HNO 3 and summer maxima for NO and NO 2 . The measurements have been compared with two-dimensional model calculations utilizing version 6.1 Stratospheric Aerosol and Gas Experiment (SAGE) II sulfate aerosol surface area density measurements through 1999 and extended to the end of the time series by repeating the 1999 values. The model-calculated HNO 3 , NO, and NO 2 stratospheric column time series agree with the measurements to within $8% after taking into account the vertical sensitivity of the ground-based measurements. The consistency between the measured and model-calculated stratospheric time series confirms the decreased impact on stratospheric reactive nitrogen chemistry of the key heterogeneous reaction that converts reactive nitrogen to its less active reservoir form as the lowerstratospheric aerosol surface area density declined by a factor of $20 after the eruption maximum.

Impact of a moderate volcanic eruption on chemistry in the lower stratosphere: balloon-borne observations and model calculations

“…As a result, the amount of ozone-depleting NO x is strongly reduced (e.g. Prather, 1992;Johnston et al, 1992;Fahey et al, 1993;Mills et al, 1993;Solomon et al, 1994;Kondo et al, 1997;Sen et al, 1998;Dhomse et al, 2015), whereas HNO 3 amounts increase (Koike et al, 1993(Koike et al, , 1994Webster et al, 1994;Rinsland et al, 2003) as shown for the Pinatubo aerosols. Different chemical impacts on stratospheric ozone are expected depending on the altitude.…”

Stratospheric and tropospheric NO<sub>2</sub> variability on the diurnal and annual scale: a combined retrieval from ENVISAT/SCIAMACHY and solar FTIR at the Permanent Ground-Truthing Facility Zugspitze/Garmisch

“…Individual measurement precisions of ≈10% have been reported as well as accuracies of ≈10% been given. Rinsland et al (2003) have pointed to a possible significant a priori contribution to the retrievals. In extension to these previous error assessments we will thereafter investigate quantitatively in full detail the impact of differing HITRAN versions, differing a priori VMR profiles, as well as the influence of the averaging kernels on the FTIR column retrievals of NO 2 .…”

Past and future simulations of NO<sub>2</sub> from a coupled chemistry-climate model in comparison with observations

“…Liley et al (2000) show however, that using short time periods in regression analyses results in large uncertainties in the trends and therefore the results of Rinsland et al (2003) cannot be meaningfully compared with those of Liley et al (2000) or those presented here. NO 2 data derived from a combination of FTIR and differential optical absorption spectroscopy measurements taken at the Network of the Detection of Stratospheric Change (NDSC) station at Jungfrauojoch (46.5 • N) have been analysed and suggest a linear increase for the period 1985-2001 of 6±2% per decade (WMO, 2003).…”

“…Using 1995-2002 Fourier Transform Infra-Red (FTIR) measurements at Kitt Peak (31.9 • N), Rinsland et al (2003) derived an NO 2 trend of 10.3±5.5% (2σ ) per decade. Liley et al (2000) show however, that using short time periods in regression analyses results in large uncertainties in the trends and therefore the results of Rinsland et al (2003) cannot be meaningfully compared with those of Liley et al (2000) or those presented here.…”