Advances in noctilucent cloud research in the space era

Avaste, O. A.; Fedynsky, A. V.; Grechko, G. M.; Sevast'yanov, V. I.; Willmann, Ch.

doi:10.1007/bf01586466

Cited by 35 publications

(12 citation statements)

References 65 publications

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“…Alternatively, a distribution of particles sizes is considered which is described by the function Ar ", over a range of sizes from rmm = 0.025 ~tm tO rma• = 1.9 ~tm, with v = -3.5. Avaste et al (1981) describe the results of microphotometring some of the Salyut-6 photographs of noctilucent clouds seen at the horizon, in the direction of the Sun. The data show quite a marked degree of forward scattering in the clouds; there is a clear brightening of the scattered light when the azimuth relative to the solar azimuth is less than 5 degrees.…”

Section: Instrumental Observationsmentioning

confidence: 99%

Noctilucent clouds

Gadsden

1982

Space Sci Rev

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Abstract. Noctilucent clouds appear during the summertime at high lantudes near the top of the mesosphere. In this review, the observattonal facts about them, obtained from ground level, by rocket sounding and from orbiting spacecraft, are reviewed. The data are not sufficiently clear and unambiguous to permit dogmatic assemon about the origin and nature of the clouds. They seem to be ice particles nucleated at very low pressures and temperatures by either meteoric smoke or by atmospheric ions. Wavepatterns m the clouds may well result from quite close relations between the troposphere and the mesosphere The very existence of the clouds leads to difficulties in explaining why there is so much water vapour at this great height in the atmosphere. To try to predict the microscopic behaviour of the cloud particles leads one into assessment of the relative importance of radiometer effects, radiauon balance, Brownian movement, electric polanzanon and the influence of Coulomb attraction on the growth of large clustered ions. Finally, a hst ~s gtven of published sources of observanonal data.

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Section: Instrumental Observationsmentioning

confidence: 99%

Noctilucent clouds

Gadsden

1982

Space Sci Rev

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“…ROSEN, 1971;FRIEND et al, 1973;CASTLEMAN et al, 1974;BIGG, 1975;FARLOW et al, 1977;GRAS, 1978). Because such gases exist in the background atmosphere, the stratosphere always contains a tenuous, ubiquitous sulfate haze (LAZRUS and GANDRUD, 1974;GANDRUD and LAZRUS, 1981a).…”

Section: Stratospheric Sulfate Aerosolsmentioning

confidence: 99%

“…Table 5 summarizes our best present understanding of noctilucent cloud properties based on a number of studies and reviews (e.g. FOGLE and HAURWITZ, 1966;THEON et al, 1967;DONAHUE et al, 1972;AVASTE et al, 1980;GADSDEN, 1982;THOMAS, 1984;GADSDEN and SCHRODER, 1989; also see Journal of Geophysical Research, Vol.94, No. D12, 1989).…”

Section: Noctilucent Cloudsmentioning

confidence: 99%

Middle Atmosphere Aerosols and Their Effects

Turco¹

1991

J. geomagn. geoelec

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The middle atmosphere holds a rich variety of particulate matter, ranging from meteoritic debris to sulfate aerosols to polar stratospheric ice clouds. Volcanic eruptions strongly perturb the stratospheric sulfate (JUNGE) layer. High-altitude "noctilucent" ice clouds condense at the cold menopause . The properties of these particles-including composition, size and geographical distribution-are discussed, and their global effects-including chemical, radiative and climatic roles-are surveyed. Polar stratospheric clouds (PSCs) catalyze reactions of chlorine compounds that "activate" otherwise inert chlorine reservoirs, leading to severe ozone depletions in the southern polar stratosphere during austral spring. PSCs also modify the composition of the polar stratosphere through complex physicochemical processes, including dehydration and denitrification. The sulfate aerosol layer can reflect solar radiation and increase the planetary albedo, thereby cooling the surface and altering the climate. Major volcanic eruptions, which enhance the stratospheric sulfate aerosol burden by a factor of 100 or more, may cause significant global climatic anomalies. Sulfate aerosols also appear capable of activating stratospheric chlorine reservoirs on a global scale. Accordingly, if atmospheric concentrations of chlorine (associated with anthropogenic use of chlorocarbons) increase by a factor of two or more in future decades, significant worldwide ozone depletions could occur.

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“…Whether it produces a net heating effect (due to "greenhouse" trapping of upward IR radiation) or a net cooling effect (due to an increased reflectance of the earthatmosphere system) depends upon the mean size (Coakley and Grams, 1976). If the mean size is ~0.1/zm (Avaste and others, 1980) the net effect is one of cooling. If the mean size were much smaller (~0.01/um) the effect would be essentially neutral due to a balancing of the heating and cooling tendencies.…”

Section: Climatological Consequencesmentioning

confidence: 99%

“…The fact that the appearance of high-altitude noctilucent clouds (NLC) is well-correlated with the temporal and spatial properties of this zone of frigid summertime air provides the best evidence available for the current belief that the cloud particles are water ice crystals (Avaste and others, 1980). Although the present atmosphere is extremely dry at these heights (a few parts per million by volume), nevertheless the few measurements of temperature available show that the air temperature is below the frost point (~ 140 K) during the NLC displays, and above the frost point when they are absent.…”

Section: Introductionmentioning

confidence: 99%

Formation of noctilucent clouds by an extraterrestrial impact

McKay

Thomas

1982

Geological Society of America Special Papers

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The impact of a large body in the oceans would inject large quantities of water through the tropopause cold trap into the stratosphere and lower mesosophere. We consider the consequences of enhanced water vapor concentrations on the middle atmosphere (50-100 km) chemistry and heat budget.The increased mixing ratio of hydrogen dramatically decreases the ozone concentration above 60 km. Catalytic reactions with odd hydrogen are the main sink of ozone in this region. The ozone reduction causes a lowering of the average height of the mesopause, as well as a lowering of the average temperature. The lower colder mesopause and the creation of saturation conditions over much of the upper mesosphere would have resulted in a permanent layer of mesospheric ice clouds of nearly world-wide extent. (At present, these exist only at high latitudes and are observed in summer as "noctilucent clouds.") The globally-averaged albedo resulting from these clouds is dependent on the particulate size and shape, and can be as high as several percent, preferentially covering the summer hemisphere. This could have important implications for the short-term climate following a large-body impact. Similar effects would also result from an encounter with a more extended object such as a swarm of cosmic debris or a dense interstellar cloud.

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Advances in noctilucent cloud research in the space era

Cited by 35 publications

References 65 publications

Noctilucent clouds

Noctilucent clouds

Middle Atmosphere Aerosols and Their Effects

Formation of noctilucent clouds by an extraterrestrial impact

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