Infrared measurements of HF and HCl total column abundances above Kitt Peak, 1977-1990 : seasonal cycles, long-term increases, and comparisons with model calculations

摘要: Series of high-resolution (∼0.01 cm−1) solar absorption spectra recorded with the McMath Fourier transform spectrometer on Kitt Peak (altitude 2.09 km, 31.9°N, 111.6°W) have been analyzed to deduce total column amounts HF 93 different days and HCl 35 between May 1977 June 1990. The results are based analysis H35Cl (1–0) vibration-rotation band R(1) lines which located at 4038.9625 2925.8970 cm−1, respectively. All data were using a multilayer, nonlinear least squares spectral fitting procedure consistent set spectroscopic line parameters. indicate rapid increase in more gradual both trends superimposed short-term variability. In addition, columns gases undergo seasonal cycle an early spring maximum fall minimum, peak-to-peak amplitudes equal 25% for 13% HCl. case HF, changes over 13 years measurement sufficiently large determine that better fit is obtained assuming linear rather than exponential time. For HCl, models equally well. Referenced calendar year 1981.0 sinusoidal time, rates (10.9±1.1)% yr−1 (5.1±0.7)% (3.17±0.11)×1014 (1.92±0.06)×1015 molecules cm−2 (2 sigma) derived, respectively; corresponding best mean (7.6±0.6)% (4.2±0.5)% sigma). Over 13-year observing period, increased by factors 3.2 1.8, Based deduced from measurements same day, HF/HCl ratio 0.14 0.23 Short-term temporal variations highly correlated; these fluctuations believed be caused dynamical variability lower stratosphere. this investigation compared previously reported time-dependent, two-dimensional model calculations emission histories photo-oxidation source molecules.