Mother-of-pearl clouds and their problems

Dieterichs, Heinz

doi:10.1007/bf02026314

Cited by 4 publications

(5 citation statements)

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“…Their heights ranged between 23 and 29km, more than twice that of the highest cirrus clouds. This range of heights was later supported by Dieterichs () and others.…”

Section: Observations Of Iridescent Clouds At the Christiania Observasupporting

confidence: 57%

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Screaming clouds

Fikke

Kristjánsson

Nordli

2017

Weather

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‘Mother‐of‐pearl clouds’ appear irregularly in the winter stratosphere at high latitudes, about 20–30km above the surface of the Earth. Mie scattering from cloud particles with sizes near the wavelength of visible light is responsible for their extraordinarily beautiful colours. There were no reported observations of such clouds before 1870. We argue that the Norwegian painter Edvard Munch may have been terrified after seeing a spectacular mother‐of‐pearl cloud event and that this experience prompted him to paint The Scream.

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“…Their heights ranged between 23 and 29km, more than twice that of the highest cirrus clouds. This range of heights was later supported by Dieterichs () and others.…”

Section: Observations Of Iridescent Clouds At the Christiania Observasupporting

confidence: 57%

“…The logbooks of the Christiania Observatory also show iridescent clouds in February 1891 and January 1892. After this, they seem not to have been reported during the period 1892–1925 (Dieterichs, ).…”

Section: Observations Of Iridescent Clouds At the Christiania Observamentioning

confidence: 93%

Screaming clouds

Fikke

Kristjánsson

Nordli

2017

Weather

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Section: Pre-satellite Eramentioning

confidence: 99%

“…In the years 1883–1886, the readers of Nature had the pleasure of following a vivid controversy between those who had observed an apparently new type of cloud and “non‐observers” or non‐believers (Dieterichs, 1950). What had happened?…”

Section: Historical Overviewmentioning

confidence: 99%

“…Before the advent of photography, there were only sketches and paintings, possibly such as Munch's "The Scream" (Figure 1d; Fikke et al, 2017;Prata et al, 2018). The clouds seemed to remain motionless at high altitude despite strong Föhn winds on the ground (Størmer, 1948), which was explained soon thereafter by Dieterichs (1950) in terms of the formation and trapping of the clouds by lee waves downstream of the Scandinavian mountain range. He interpreted moving clouds as break-off lee wave clouds drifting with the overall air flow, while small motions could simply be related to changes in the quasi-stationary wave system, ideas that were confirmed quantitatively more than 50 years later by high-resolution meteorological models (Dhaniyala et al, 2002;.…”

Section: Pre-satellite Eramentioning

confidence: 99%

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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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Polar Stratospheric Clouds and Sulfate Aerosol Particles: Microphysics, Denitrification and Heterogeneous Chemistry

Peter

Grooß

2011

Stratospheric Ozone Depletion and Climate Change

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Clouds and aerosol particles play important roles in the chemistry of the polar winter stratosphere. Under extremely cold conditions their surfaces host heterogeneous chemical reactions, which—depending on temperature and aerosol loading—may lead to a very fast transformation of chlorine containing reservoir compounds into active, ozone destroying chlorine. Furthermore, polar stratospheric clouds (PSCs) may generate large nitric-acid-containing particles, which sediment rapidly, thereby denitrifying the stratospheric air and disabling reactive nitrogen species to deactivate the ozone-destroying chlorine. Both processes, heterogeneous chemistry and denitrification provide the basis for chlorine-catalyzed ozone destruction, which under sustained cold conditions leads to the ozone hole over the Antarctic and substantial ozone depletion over the Arctic. While the principles of these polar ozone loss mechanisms have long been recognized, very recently new measurements and modeling of PSCs have cast serious doubts on our understanding of some of the most fundamental processes of PSC formation and heterogeneous chemistry. One important open question is whether the nucleation of nitric acid hydrates and subsequent denitrification are governed predominantly by ice-assisted or ice-free processes. A number of previously discussed processes appear to be unlikely from today's perspective, such as homogeneous nucleation of hydrates in supercooled liquid solution droplets, nucleation of hydrates in glassy aerosols or pseudo-heterogeneous nucleation at a droplet/vapor interface. However, while heterogeneous nucleation of hydrates on water ice is accepted in the light of laboratory experiments and field observations, an unidentified ice-free heterogeneous nucleation process, e.g. on dust particles, appears to be required in order to explain a number of very recent field observations, in particular by the downward-looking LiDAR on the CALIPSO satellite in the Arctic winter 2009–2010. This result is perplexing and reverses the previous understanding of PSC formation, because there is currently no conclusive laboratory evidence supporting this finding. There are also open issues concerning chlorine activation on solid and liquid PSC and cold stratospheric aerosol particles. In particular, activation reaction rates on nitric acid hydrate particles retain an uncertainty of almost two orders of magnitude. However, while this uncertainty remains a physico-chemical flaw, it appears not to hamper our ability to understand and predict chlorine activation and ozone loss, as liquid particles are usually the dominant chlorine processors. Liquid phase heterogeneous and multi-phase chemistry is much less uncertain. It appears that under many circumstances, the formation of PSCs is not even required for rapid chlorine activation, rather the heterogeneous chemistry on sufficiently cold background aerosol ensures the dissolution and activation of chlorine reservoir species such as HCl.

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Mother-of-pearl clouds and their problems

Cited by 4 publications

References 5 publications

Screaming clouds

Screaming clouds

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

Polar Stratospheric Clouds and Sulfate Aerosol Particles: Microphysics, Denitrification and Heterogeneous Chemistry

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