Unexpectedly low ozone concentration in midlatitude tropospheric ice clouds: A case study

Reichardt, Jens; Ansmann, Albert; Serwazi, Marcus; Weitkamp, C.; Michaelis, W.

doi:10.1029/96gl01856

Cited by 55 publications

(26 citation statements)

References 13 publications

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“…This depletion occurs at the lower limit of the SAGE sensitivity, and the reality of SAGE data at low latitudes has been questioned on the grounds that large depletion is not expected there. But there is evidence that cirrus clouds, which are abundant at the altitudes and latitudes in question, may activate ozone depletion (Borrmann et al 1996 ;Reichardt et al 1996). At any rate, as a sensitivity study, for the want of better measurements, we take the SAGE data at face value.…”

Section: Recent Years: 1979-1995mentioning

confidence: 99%

The missing climate forcing

Hansen

Sato

Lacis

et al. 1997

Phil. Trans. R. Soc. Lond. B

143

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SUMMARYObserved climate change is consistent with radiative forcings on several time scales for which the dominant forcings are known, ranging from the few years after a large volcanic eruption to glacial-tointerglacial changes. In the period with most detailed data, 1979 to the present, climate observations contain clear signatures of both natural and anthropogenic forcings. But in the full period since the industrial revolution began, global warming is only about half of that expected due to the principal forcing, increasing greenhouse gases. The direct radiative effect of anthropogenic aerosols contributes only little towards resolving this discrepancy. Unforced climate variability is an unlikely explanation. We argue on the basis of several lines of indirect evidence that aerosol effects on clouds have caused a large negative forcing, at least k1 Wm −# , which has substantially offset greenhouse warming. The tasks of observing this forcing and determining the microphysical mechanisms at its basis are exceptionally difficult, but they are essential for the prognosis of future climate change.

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Section: Recent Years: 1979-1995mentioning

confidence: 99%

The missing climate forcing

Hansen

Sato

Lacis

et al. 1997

Phil. Trans. R. Soc. Lond. B

143

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show abstract

“…Heterogeneous reactions on or inside of these droplets or cloud particles could convert the inactive reservoir species C1ONO2, HC1, and HOC1 into reactive forms of chlorine (Solomon et al [1986]), which ultimately may influence ozone. Cases of "unusually low ozone in cirrus clouds" have recently been reported by Reichardt et al [1996], and the potential of cirrus clouds for heterogeneous chlorine activation has been addressed by Borrmann et al [1996]. Depending on the phase and chemical composition of the aerosol particles and on the abundances of water vapor and the reservoir species, the reaction efficiencies can vary over wide ranges (Hanson et The C10 …”

Section: Introductionmentioning

confidence: 99%

On the occurrence of ClO in cirrus clouds and volcanic aerosol in the tropopause region

Borrmann

Solomon

Avallone

et al. 1997

Geophysical Research Letters

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Abstract.Airborne observations during descents of the ER-2 through layers of volcanic aerosol (Mount Pinatubo eruption of 1991) and a cirrus cloud are utilized to study the the abundance of C10 and its relation to aerosol surface area in the midlatitude tropopause region. During a cirrus event near the tropopause C10 mixing ratios up to 2.7 pptv were detected and near the tropopause C10 levels from a few to 70 pptv were found. These measurements are associated with large experimental uncertainties but demonstrate the possible presence of C10 inside cirrus clouds and near the tropopause. Model calculations show that possible enhancements of C10 by heterogeneous chemistry on cirrus cloud particles could considerably increase the ozone loss rates and could have implications for the ozone budget in this region. It is not possible to decide from the limited data base whether the observed C10 levels are due to transport or heterogeneous chemistry.

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“…Borrmann et al (1996) showed that cirrus clouds might lead to heterogeneous Chemical reactions similar to those taking place on Polar Stratospheric Clouds and suggested that these clouds could affect the abundances of ozone. Some observational studies (Reichard et al, 1996;Roumeau et al, 2000) have found such diminutions of ozone in the presence of cirrus at both mid-latitude and tropical sites. While several studies (Stowe et al, 1989;Wylie et al, 1994;Wang et al, 1996) reported frequent cirrus clouds near the tropopause, Solomon et al (1997) suggested that the chemistry associated to these clouds at mid-latitudes may contribute ozone depletion observed at mid-latitudes in the lower stratosphere and would permit to reconcile observed and modeled ozone trends at mid-latitudes (Meilinger et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Indications of thin cirrus clouds in the stratosphere at mid-latitudes

et al. 2005

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Abstract. This study is devoted to the possible presence of cirrus clouds in the stratosphere. Three months of lidar data collected in the south of France (44 • N) for detection of stratospheric cirrus are carefully analyzed. Most of the cirrus clouds appear to be located in the troposphere below the dynamical tropopause even when the cloud top is close to the thermal tropopause. Ten cirrus cases are found to be unambiguously located above the local dynamical tropopause according to high-resolution PV advection calculations. The highest cloud detected above the local tropopause (nearly 3 km above) is observed inside air masses that originate from the sub-tropical regions and are then transported rapidly to mid-latitudes through isentropic transport. The details of the air mass history is described with a 3-D trajectory model. The back-plumes indicate that the air mass, moist with respect to typical stratospheric air, was transported from the subtropical troposphere to the lowermost stratosphere in 4 days before detection above France. A continuous cooling of 5-10 • along the trajectory took place during its transit. This cooling could have been partly responsible for the thin cirrus layer detected.

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Unexpectedly low ozone concentration in midlatitude tropospheric ice clouds: A case study

Cited by 55 publications

References 13 publications

The missing climate forcing

The missing climate forcing

On the occurrence of ClO in cirrus clouds and volcanic aerosol in the tropopause region

Indications of thin cirrus clouds in the stratosphere at mid-latitudes

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