Infrared and visible Fourier-transform spectra of sulfuric-acid-water aerosols at 230 and 294 K
APPLIED OPTICS 38:30 (1999) 6408-6420
A three-dimensional model simulation of the impact of Mt. Pinatubo aerosol on the Antarctic ozone hole
Quarterly Journal of the Royal Meteorological Society Wiley 124:549 (1998) 1527-1558
Radiative forcing from the 1991 Mount Pinatubo volcanic eruption
J GEOPHYS RES-ATMOS 103 (1998) 13837–13857-13837–13857
Abstract:
Volcanic sulfate aerosols in the stratosphere produce significant long-term solar and infrared radiative perturbations in the Earth’s atmosphere and at the surface, which cause a response of the climate system. Here we study the fundamental process of the development of this volcanic radiative forcing, focusing on the eruption of Mount Pinatubo in the Philippines on June 15, 1991. We develop a spectral-, space-, and time-dependent set of aerosol parameters for 2 years after the Pinatubo eruption using a combination of SAGE II aerosol extinctions and UARS-retrieved effective radii, supported by SAM II, AVHRR, lidar and balloon observations. Using these data, we calculate the aerosol radiative forcing with the ECHAM4 general circulation model (GCM) for cases with climatological and observed sea surface temperature (SST), as well as with and without climate response. We find that the aerosol radiative forcing is not sensitive to the climate variations caused by SST or the atmospheric response to the aerosols, except in regions with varying dense cloudiness. The solar forcing in the near infrared contributes substantially to the total stratospheric heating. A complete formulation of radiative forcing should include not only changes of net fluxes at the tropopause but also the vertical distribution of atmospheric heating rates and the change of downward thermal and net solar radiative fluxes at the surface. These forcing and aerosol data are available for GCM experiments with any spatial and spectral resolution.A three-dimensional model simulation of the impact of Mt. Pinatubo aerosol on the Antarctic ozone hole
Quarterly Journal of the Royal Meteorological Society 124:549 (1998) 1527-1558
Abstract:
Seasonal integrations of a three-dimensional fully coupled model of the radiation, dynamics and chemistry of the stratosphere and mesosphere are presented for the southern hemisphere spring. Included in the model are heterogeneous reactions which take place in sulphuric acid aerosol droplets as well as on the surface of Polar Stratospheric Clouds (PSCs). Calculations are performed for background levels of stratospheric aerosol and for conditions following the eruption of Mt. Pinatubo. For the volcanic case, surface area densities are derived from Improved Stratospheric and Mesospheric Sounder data. For background aerosol loadings there are significant increases in HOx and ClOx, as well as reductions in NOx. These effects are enhanced following the Pinatubo eruption but saturate at relatively low aerosol levels and hence can persist in the stratosphere for several years. Where pSCs are predicted to form, the sulphate aerosol chemistry does not operate in the model since the aerosols are incorporated as nuclei within the PSCs. In contrast, on the edge of the ozone hole, where temperatures are only just too high for the formation of PSCs, destruction by aerosol can result in further total ozone depletion of order 20 Dobson Units. In addition, the size and duration of the ozone hole are both increased by the presence of volcanic aerosols. The results support previous suggestions that the eruption of Mt. Pinatubo resulted in a temporary increase in ozone depletion over Antarctica and elsewhere.Radiative forcing from the 1991 Mount Pinatubo volcanic eruption
Journal of Geophysical Research Atmospheres 103:D12 (1998) 13837-13857