Gaseous Sulfuric Acid and Sulfur Dioxide Measurements in the Arctic Troposphere and Lower Stratosphere: Implications for Hydroxyl Radical Abundances

Abstract

Measurements of gaseous sulfuric acid and sulfur dioxide were made in the winter arctic troposphere and lower stratosphere, using aircraft-borne mass spectrometers. The measurements, covering altitudes between 3.5 and 11.4 km, took place on 14 and 18 February, 1987 in Northern Scandinavia. Our mean measured H2SO4-concentrations are around 1.0–3.0 · 105 cm−3 and the measured SO2-volume mixing ratios are around 50–400 pptV in the troposphere and decrease steeply above the tropopause to about 10 pptV. The combined H2SO4- and SO2-measurements offer an interesting opportunity to infer hydroxyl radical concentrations. Inferred OH-concentrations are around 0.1–1.0 · 105 cm−3, roughly consistent with model predictions.