Background stratospheric aerosol and polar stratospheric cloud reference models

McCormick, M. P.; Wang, P.-H.; Pitts, M.C.

doi:10.1016/0273-1177(96)00057-9

Cited by 9 publications

(2 citation statements)

References 15 publications

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“…The initial SAM II results from 1978/79 were intriguing, showing wintertime PSCs to be strongly associated with low temperature and much more prevalent in the Antarctic than in the Arctic, increasing the Antarctic stratospheric optical depth in a distinct manner for a period of about three months (McCormick et al., 1981). As the data record lengthened, it revealed a high level of annual regularity in Antarctic PSC activity, with sharp increases in stratospheric optical depth beginning each June and ending in September (McCormick et al., 1993). Similar to a heartbeat, the maxima were followed by peculiar minima in October, possibly a cleansing of the air due to scavenging of aerosol by sedimenting large PSC particles.…”

Section: Historical Overviewmentioning

confidence: 99%

Polar Stratospheric Clouds: Satellite Observations, Processes, and Role in Ozone Depletion

Tritscher

Pitts

Poole

et al. 2021

Reviews of Geophysics

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Polar stratospheric clouds (PSCs) play important roles in stratospheric ozone depletion during winter and spring at high latitudes (e.g., the Antarctic ozone hole). PSC particles provide sites for heterogeneous reactions that convert stable chlorine reservoir species to radicals that destroy ozone catalytically. PSCs also prolong ozone depletion by delaying chlorine deactivation through the removal of gas-phase HNO 3 and H 2 O by sedimentation of large nitric acid trihydrate (NAT) and ice particles. Contemporary observations by the spaceborne instruments Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), Microwave Limb Sounder (MLS), and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) have provided an unprecedented polar vortex-wide climatological view of PSC occurrence and composition in both hemispheres. These data have spurred advances in our understanding of PSC formation and related dynamical processes, especially the firm evidence of widespread heterogeneous nucleation of both NAT and ice PSC particles, perhaps on nuclei of meteoritic origin. Heterogeneous chlorine activation appears to be well understood. Reaction coefficients on/in liquid droplets have been measured accurately, and while uncertainties remain for reactions on solid NAT and ice particles, they are considered relatively unimportant since under most conditions chlorine activation occurs on/in liquid droplets. There have been notable advances in the ability of chemical transport and chemistry-climate models to reproduce PSC temporal/spatial distributions and composition observed from space. Continued spaceborne PSC observations will facilitate further improvements in the representation of PSC processes in global models and enable more accurate projections of the evolution of polar ozone and the global ozone layer as climate changes.Plain Language Summary Polar stratospheric clouds (PSCs) occur during winter and early spring in the polar stratosphere, when temperatures are low enough to enable cloud formation despite the extremely dry conditions. Ground-based PSC sightings date back to the late 19th century, but they were little more than a scientific curiosity until the discovery of the Antarctic ozone hole in 1985. Soon thereafter, it was shown that PSCs play a crucial role in converting stable halogen (mainly chlorine) species of anthropogenic origin into reactive gases that rapidly destroy ozone. Considerable progress was made over the next two decades in quantifying these processes through laboratory studies, field campaigns, and limited spaceborne observations. We are now reaping the benefits of new PSC observations over the entire polar regions from three complementary 21st century spaceborne instruments. This study reviews these instruments and highlights new findings on PSC occurrence and composition. These datasets have also triggered advances in understanding how PSCs form and the influence of atmospheric dynamics, as well as improvements in how detailed cloud processes are approximated in global models. Thi...

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Section: Historical Overviewmentioning

confidence: 99%

Polar Stratospheric Clouds: Satellite Observations, Processes, and Role in Ozone Depletion

Tritscher

Pitts

Poole

et al. 2021

Reviews of Geophysics

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“…Model simulations of DLP were carried out to confirm a general consistency between measurements and theory. These were performed using the vector limb radiative transfer code of McLinden et al [2002b] and background stratospheric aerosol profiles adapted from McCormick et al [1996]. Model DLP can be calculated in two ways.…”

Section: Osiris Observations and Modelling Of Limb Polarizationmentioning

confidence: 99%

Derivation of polarization from Odin/OSIRIS limb spectra

McLinden¹

2004

Geophysical Research Letters

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[1] A new technique for deriving the degree of linear polarization from limb-scattered sunlight radiance measurements is presented and applied to Odin/OSIRIS. In this technique, the measured OSIRIS grating efficiency spectrum is fit to OSIRIS limb spectra using the differential optical absorption spectroscopy technique and the resultant fitting constant is shown to represent the difference in linear polarization between two tangent heights. The validity of this technique is confirmed using simulations from a vector limb radiative transfer model. OSIRIS scans of the difference in linear polarization from October 2003 are shown to be very sensitive to stratospheric and upper tropospheric aerosols, including background sulphates, clouds, and polar stratospheric clouds.

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