Observations of Antarctic polar stratospheric clouds by POAM II: 1994–1996

Fromm, M.; Lumpe, J. D.; Bevilacqua, R. M.; Shettle, E. P.; Hornstein, J.; Massie, Steven T.; Fricke, K. H.

doi:10.1029/97jd00794

Cited by 63 publications

(72 citation statements)

References 24 publications

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“…Several satellite sensors have observed PSCs in the SH, such as SAM II (Poole and Pitts 1994), POAM II (Fromm et al 1997), and POAM III (Nedoluha et al 2003), which had latitudinal coverages similar to the coverage by ILAS-II. All observations, including those by ILAS-II, showed the largest PPSC values in August and September.…”

Section: Discussionmentioning

confidence: 99%

“…1994;Fig. 2a) and PPSC values in June from 1994 to 1996 were 15 to 20% (Fromm et al 1997; Fig. 10), although PPSC in June 2002 was exceptionally high at 60% (Nedoluha et al 2003).…”

Section: Discussionmentioning

confidence: 99%

“…Activated chlorine causes severe ozone depletion, especially in the Southern Hemisphere (SH), which is known as the "ozone hole". The climatology of PSC frequency in the SH was examined using aerosol data from the Stratospheric Aerosol Measurement (SAM) II from 1978 to 1989 (Poole and Pitts 1994), data from the Polar Ozone and Aerosol Measurement (POAM) II from 1994 to 1996 (Fromm et al 1997), and data from multiple solar occultation sensors from 1978 to 2000 . Poole and Pitts (1994) examined the relationship between PSC frequency and temperature and showed that PSC formation in the SH is less likely later in PSC season than earlier.…”

Section: Introductionmentioning

confidence: 99%

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Variation in PSC Occurrence Observed with ILAS-II over the Antarctic in 2003

Saitoh

Hayashida

Sugita

et al. 2006

SOLA

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The Improved Limb Atmospheric Spectrometer (ILAS)-II frequently observed polar stratospheric clouds (PSCs) in the Southern Hemisphere (SH) throughout the winter of 2003. Simultaneous observations of the aerosol extinction coefficient (AEC) at 780 nm, nitric acid, and water vapor data were analyzed to investigate the ambient thermodynamic conditions associated with observed PSCs. PSCs were first observed with ILAS-II at the end of May, and observed most frequently in August/September as temperatures cooled. At approximately 20 km late in the PSC season, however, PSCs were less likely to occur, despite cold temperatures, because of the lower concentration of nitric acid due to denitrification caused by sedimentation of previously occurring PSCs. The probability of PSC occurrence and the probability of ambient temperatures colder than nitric acid trihydrate (NAT) saturation temperature (TNAT ) were well correlated below 20 km throughout the winter. In contrast, PSC frequency at 22 km from late August to early September was low even when temperatures were sufficiently colder than TNAT; this is, at least, partly because of the decrease in background aerosol particles in the atmosphere. IntroductionPolar stratospheric clouds (PSCs) consist mainly of nitric acid and water/ice and form in winter and early spring in the lower stratosphere over both polar regions (e.g., Solomon 1999). PSCs play a crucial role in ozone depletion processes; they provide surfaces for heterogeneous reactions that convert inactive chlorine into active chorine (e.g., Solomon 1999) and cause denitrification (e.g., Fahey et al. 1990) and nitrification (e.g., H ubler et al. 1990). Activated chlorine causes severe ozone depletion, especially in the Southern Hemisphere (SH), which is known as the "ozone hole". The climatology of PSC frequency in the SH was examined using aerosol data from the Stratospheric Aerosol Measurement (SAM) II from 1978to 1989(Poole and Pitts 1994, data from the Polar Ozone and Aerosol Measurement (POAM) II from 1994 to 1996 (Fromm et al. 1997), and data from multiple solar occultation sensors from 1978 to 2000 .Poole and Pitts (1994) examined the relationship between PSC frequency and temperature and showed that PSC formation in the SH is less likely later in PSC season than earlier. Other studies (e.g., Watterson and Tuck 1989;Hervig et al. 1997;Mergenthaler et al. 1997) have suggested that PSC formation late in PSC season in the SH is strongly affected by preceding denitrification and dehydration. However, there have been few studies on the variability of the relationship between PSC frequency and temperature over the course of a PSC season that are based on extensive observations of aerosols, nitric acid, and water vapor in the SH.Against this background, we used data obtained by the PSC identification and TNAT calculationPSCs were identified from ILAS-II AEC data over the SH using methods similar to those for ILAS data in the NH (Hayashida et al. 2000). First, averages and standard deviations for ILAS-II AEC data at te...

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Section: Discussionmentioning

confidence: 99%

“…1994;Fig. 2a) and PPSC values in June from 1994 to 1996 were 15 to 20% (Fromm et al 1997; Fig. 10), although PPSC in June 2002 was exceptionally high at 60% (Nedoluha et al 2003).…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Variation in PSC Occurrence Observed with ILAS-II over the Antarctic in 2003

Saitoh

Hayashida

Sugita

et al. 2006

SOLA

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“…It is very unlikely, however, to account for the initial NO2 increases observed above 1000 K between July and August since PSCs were not observed at those altitudes [Fromm et al, 1997]. Production of NO2 as sunlight returns to the polar regions, dissociating the stratospheric C1ONO2 and HNO3 reservoirs, is certainly contributing to the NO2 increases measured by POAM II in the winter and spring.…”

Section: No• Profilesmentioning

confidence: 99%

Polar Ozone and Aerosol Measurement (POAM) II stratospheric NO₂, 1993–1996

Randall¹,

Rusch²,

Bevilacqua³

et al. 1998

J. Geophys. Res.

101

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Abstract. We describe, for the first time, measurements of stratospheric nitrogen dioxide (NO2) by the Polar Ozone and Aerosol Measurement (POAM II) instrument. Measurements span October 1993 through mid-November 1996 and cover latitude ranges from 55 ø to 72øN and from 63 ø to 88øS. Comparisons with coincident satellite and space shuttle observations show good agreement and confirm the validity of POAM II measurements for scientific investigations. Overall seasonal variations in both hemispheres are qualitatively consistent with standard photochemistry. In the austral late winter/early spring of 1994, however, anomalously high NO2 mixing ratios were observed above 22 km. We conclude that these high NO2 levels resulted from downward transport of NOx-enhanced air from the mesosphere or thermosphere inside the polar vortex. Enhanced NO2 mixing ratios in 1994 were factors of-l.3 and 2.5 larger than at the corresponding times in 1995 and 1996. We conclude that POAM II observations of coincident, localized reductions in ozone of up to 40% were caused by the increased stratospheric NOx via the standard catalytic NO• cycle.

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“…Long-term solar occultation data records from the Stratospheric Aerosol Measurement (SAM) II (Poole and Pitts, 1994) and Polar Ozone and Aerosol Measurement (POAM) II and III (Fromm et al, 1997(Fromm et al, , 1999 instruments have established the general climatology of PSCs such as their occurrence at very cold temperatures (T <195-200 K) and their spatial distribution and seasonal variability in both the Arctic and Antarctic. Measurements from polarization sensitive airborne and ground-based lidar systems have also made valuable contributions to our understanding of PSCs.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Polar Stratospheric Clouds with spaceborne lidar: CALIPSO and the 2006 Antarctic season

et al. 2007

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Abstract. The role of polar stratospheric clouds in polar ozone loss has been well documented. The CALIPSO satellite mission offers a new opportunity to characterize PSCs on spatial and temporal scales previously impossible. A PSC detection algorithm based on a single wavelength threshold approach has been developed for CALIPSO. The method appears to accurately detect PSCs of all opacities, including tenuous clouds, with a very low rate of false positives and few missed clouds. We applied the algorithm to CALIOP data acquired during the 2006 Antarctic winter season from 13 June through 31 October. The spatial and temporal distribution of CALIPSO PSC observations is illustrated with weekly maps of PSC occurrence. The evolution of the 2006 PSC season is depicted by time series of daily PSC frequency as a function of altitude. Comparisons with "virtual" solar occultation data indicate that CALIPSO provides a different view of the PSC season than attained with previous solar occultation satellites. Measurement-based time series of PSC areal coverage and vertically-integrated PSC volume are computed from the CALIOP data. The observed area covered with PSCs is significantly smaller than would be inferred from the commonly used temperature-based proxy T NAT but is similar in magnitude to that inferred from T STS . The potential of CALIOP measurements for investigating PSC composition is illustrated using combinations of lidar backscatter and volume depolarization for two CALIPSO PSC scenes.

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Observations of Antarctic polar stratospheric clouds by POAM II: 1994–1996

Cited by 63 publications

References 24 publications

Variation in PSC Occurrence Observed with ILAS-II over the Antarctic in 2003

Variation in PSC Occurrence Observed with ILAS-II over the Antarctic in 2003

Polar Ozone and Aerosol Measurement (POAM) II stratospheric NO₂, 1993–1996

Characterization of Polar Stratospheric Clouds with spaceborne lidar: CALIPSO and the 2006 Antarctic season

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Observations of Antarctic polar stratospheric clouds by POAM II: 1994–1996

Cited by 63 publications

References 24 publications

Variation in PSC Occurrence Observed with ILAS-II over the Antarctic in 2003

Variation in PSC Occurrence Observed with ILAS-II over the Antarctic in 2003

Polar Ozone and Aerosol Measurement (POAM) II stratospheric NO2, 1993–1996

Characterization of Polar Stratospheric Clouds with spaceborne lidar: CALIPSO and the 2006 Antarctic season

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Polar Ozone and Aerosol Measurement (POAM) II stratospheric NO₂, 1993–1996