Polar stratospheric cloud climatology based on Stratospheric Aerosol Measurement II observations from 1978 to 1989
- NASA, Langley Research Center, Hampton, VA (United States)
The probability of polar stratospheric cloud (PSC) occurrence in the Antarctic and Arctic has been estimated using Stratospheric Aerosol Measurement (SAM) II aerosol extinction data from 1978 to 1989. Antarctic PSCs are typically observed by SAM II from mid-May to early November, with a maximum zonal average probability of about 0.6 at 18-20 km in August. The typical Arctic PSC season extends only from late November to early March, with a peak zonal average probability of about 0.1 in early February at 20-22 km. There is considerable year-to-year variability in Arctic PSC sightings because of changes in the dynamics of the northern polar vortex. Year-to-year variability in Antarctic sightings is most prominent in the number of late season clouds. Maximum PSC sighting probabilities in both polar regions occur in the region from 90 deg W through the Greenwich meridian to 90 deg E, where temperatures are coldest on average. Arctic sighting probabilities approach zero outside this region, but clouds have been sighted in the Antarctic at all longitudes during most months. Inferred PSC formation temperatures remain constant throughout the Arctic winter and are similar to those in early Antarctic winter. PSC formation temperatures in the Antarctic drop markedly in the 15 to 20-km region by September, a pattern consistent with the irreversible loss of HNO3 and H2O vapor in sedimenting PSC particles.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 79500
- Journal Information:
- Journal of Geophysical Research, Vol. 99, Issue D6; Other Information: PBD: Jun 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
High-latitude stratospheric aerosols measured by the SAM II satellite system in 1978 and 1979
The interannual variability of polar stratospheric clouds and related parameters in Antarctica during September and October