Snow Formation Research Articles

Greenland ice core studies

Greenland deep ice cores represent continuous sequences of deposits spanning the last up to several hundred thousand years. Isotopes and impurities in the ice reveal a broad spectrum of information on past environmental conditions in the North Atlantic region, for example climatic changes in terms of surface temperature and annual precipitation; turbidity and chemical composition of the atmosphere, including its CO 2 concentration; volcanic activity and its climatic impact; and cosmic radiation flux changes in the past. One of the fundamental parameters in ice core studies is the isotopic composition of the ice, for example the 18O concentration (on the relative δ-scale), which varies in phase with the temperature of snow formation. The seasonal variations allow identification of annual layers in the core and, hence, absolute dating back to at least 8000 yrs. B.P. With some reservations, smoothed δ-records may be interpreted in terms of climatic temperature changes, cp. Fig.1, which shows δ-profiles along two deep ice cores from Dye 3 (southeast Greenland) and Camp Century (northwest Greenland). The latter spans all of the last glaciation and the preceding interglacial (Eem). The time scale in units of 10 3 yrs. B.P. has been derived by comparison of the most predominant °-features with their analogues in sea sediment cores (Dansgaard et al., 1982). The dramatic δ-shifts in times of full glacial severity seem to recur with a quasi-periodicity of 2550 yrs., perhaps caused by abrupt changes of the North Atlantic sea-ice cover. Spectral data analysis by the maximum entropy method shows similar, but greatly damped δ-oscillations in the well dated post-glacial part of the Camp Century record, in antiphase with independent estimates on world-wide degree of glaciation (Dansgaard et al., 1984). Figure 2 (left) shows the deepest 340 m of the Dye 3 δ-profile plotted on a linear depth scale. The very deepest 25 m of ice is silty, and the δ's are higher than in Holocene ice indicating a time of deposition with unusually high temperature of formation, probably the Eemian interglacial. However, the record is hardly continuous that far back in time. Fig.2 (middle) shows some of the δ-oscillations in detail, and Fig.2 (right) gives further details of three representative δ-shifts along with a dust concentration profile (increasing towards left). The dust is probably brought to Greenland mainly from distant areas covered by loss. The dust content changes less abrupt than δ, and not at exactly the same depth, which indicates that the measured δ shifts are not due to temporal discontinuities in the ice core. The general antiphase between dust content and δ suggests higher storminess in times of lower δ's. The circles are CO 2 concentrations in air inclusions in the ice, but it is still doubtful if they can be interpreted in terms of past atmospheric CO 2 concentrations (Hammer et al., 1980). Great volcanic eruptions inject acid gases into the stratosphere, particularly sulphuric gases, which are spread all over the hemisphere under oxydation. The strong acids re-enter the troposphere, and are subsequently washed out by precipitation causing acid layers in the ice sheets. Hence, acidity profiles along the Holocene part of the ice cores reveal violent volcanic activity in the Northern Hemisphere, and comparison with the δ profiles suggest a substantial cooling impact on the climate (Hammer et al., 1980).

Greenland ice core studies

Abstract Greenland deep ice cores represent continuous sequences of deposits spanning the last up to several hundred thousand years. Isotopes and impurities in the ice reveal a broad spectrum of information on past environmental conditions in the North Atlantic region, for example climatic changes in terms of surface temperature and annual precipitation; turbidity and chemical composition of the atmosphere, including its CO 2 concentration; volcanic activity and its climatic impact; and cosmic radiation flux changes in the past. One of the fundamental parameters in ice core studies is the isotopic composition of the ice, for example the 18 O concentration (on the relative δ-scale), which varies in phase with the temperature of snow formation. The seasonal variations allow identification of annual layers in the core and, hence, absolute dating back to at least 8000 yrs. B.P. With some reservations, smoothed δ-records may be interpreted in terms of climatic temperature changes, cp. Fig.1, which shows δ-profiles along two deep ice cores from Dye 3 (southeast Greenland) and Camp Century (northwest Greenland). The latter spans all of the last glaciation and the preceding interglacial (Eem). The time scale in units of 10 3 yrs. B.P. has been derived by comparison of the most predominant °-features with their analogues in sea sediment cores (Dansgaard et al., 1982). The dramatic δ-shifts in times of full glacial severity seem to recur with a quasi-periodicity of 2550 yrs., perhaps caused by abrupt changes of the North Atlantic sea-ice cover. Spectral data analysis by the maximum entropy method shows similar, but greatly damped δ-oscillations in the well dated post-glacial part of the Camp Century record, in antiphase with independent estimates on world-wide degree of glaciation (Dansgaard et al., 1984). Figure 2 (left) shows the deepest 340 m of the Dye 3 δ-profile plotted on a linear depth scale. The very deepest 25 m of ice is silty, and the δ's are higher than in Holocene ice indicating a time of deposition with unusually high temperature of formation, probably the Eemian interglacial. However, the record is hardly continuous that far back in time. Fig.2 (middle) shows some of the δ-oscillations in detail, and Fig.2 (right) gives further details of three representative δ-shifts along with a dust concentration profile (increasing towards left). The dust is probably brought to Greenland mainly from distant areas covered by loss. The dust content changes less abrupt than δ, and not at exactly the same depth, which indicates that the measured δ shifts are not due to temporal discontinuities in the ice core. The general antiphase between dust content and δ suggests higher storminess in times of lower δ's. The circles are CO 2 concentrations in air inclusions in the ice, but it is still doubtful if they can be interpreted in terms of past atmospheric CO 2 concentrations (Hammer et al., 1980). Great volcanic eruptions inject acid gases into the stratosphere, particularly sulphuric gases, which are spread all over the hemisphere under oxydation. The strong acids re-enter the troposphere, and are subsequently washed out by precipitation causing acid layers in the ice sheets. Hence, acidity profiles along the Holocene part of the ice cores reveal violent volcanic activity in the Northern Hemisphere, and comparison with the δ profiles suggest a substantial cooling impact on the climate (Hammer et al., 1980).

Deuterium and oxygen 18 in precipitation: Modeling of the isotopic effects during snow formation

The classical Rayleigh model assuming isotopic equilibrium fails to explain the deuterium and oxygen 18 contents of polar snow. This model leads to too high temperature‐isotope gradients (both for δD and δ18O), to too low δD ‐ δ18O slopes, and consequently to an excessively large range of deuterium excess values (d = δD ‐ 8δ18O). We present a new model that takes into account the existence of an isotopic kinetic effect at snow formation as a result of the fact that vapor deposition occurs in an environment supersaturated over ice. This kinetic effect is thoroughly discussed from a microphysical point of view and tested against experimental data and field observations. This new formulation reconciles predicted and observed values both for the temperature‐isotope and δD ‐ δD18O relationships for reasonable values of supersaturation over ice.

Climatic information over the last century deduced from a detailed isotopic record in the south pole snow

A continuous and very detailed deuterium profile was obtained from the analysis of about 900 firn samples from the south pole representing the snow accumulated over the last 100 years. Seasonal variations are well preserved in the firn, allowing the samples to be dated back to 1887 with an accuracy probably better than 5 years. This dating is consistent with the results of other independent methods, such as stratigraphic observations (back to 1927) and artificial β radioactivity and tritium measurements (back to 1955). The resulting mean annual accumulation over the 1887–1978 period is equal to 9.2 g cm−2. The value between 1887 and 1957 (9.5 g cm−2) is significantly higher (30% and 40%) than values previously obtained at the same site over comparable time spans. A decrease in annual snow accumulation is deduced from a comparison of the 1887–1930 and 1930–1978 periods (from 10.0 to 8.5 g cm−2). From a thorough examination of data relative to the very well documented 1957–1978 period, mean annual and maximum deuterium values and annual deuterium amplitude are shown to be correlated with the corresponding mean annual and summer temperatures and the annual temperature amplitude. The degree of correlation depends on the tropospheric level considered. On the other hand, winter temperature and deuterium minima are poorly correlated, which is attributable to the large temperature inversion during winter. Experimental temperature‐isotope (D and 18O) gradients are consistent with theoretical gradients, taking into account that snow formation is a nonequilibrium process. As a whole, this work is very encouraging for the use of stable isotopes as a tool for past temperature reconstruction over periods for which only weak variation are expected. This is applied over the 1887–1978 period to the mean annual, winter, and summer temperatures along with the annual temperature amplitude.

Comments on “Global mass and energy requirements for glacial oscillations and their implications for mean ocean temperature oscillations”

The article by Saltzman (1977) in a recent issue of Tellus presents a number of interesting problems. Saltzman assumes that the latent heat of fusion released during the growth of the Wiirm/Wisconsin continental ice-sheets was absorbed by the oceans, since there might be radiative balance at the top of the atmosphere. It is not clear from his article as to why some or all of this additional latent heat should not be radiated directly to space. This would seem likely since the additional energy will be released by the formation of snow in low/medium level clouds near or over the ice sheets, and these clouds are already radiating to space. DOI: 10.1111/j.2153-3490.1978.tb00833.x

冬の季節風による降雪の化学的研究:大陸からのエーロゾルと水蒸気の寄与について

冬の季節風による降雪の化学的研究:大陸からのエーロゾルと水蒸気の寄与について

The physics of clouds and rain

This review outlines current understanding of the physical processes which lead to the formation of clouds, snow and rain and indicates some of the questions which are still the subject of active research.

Factory Snow

Asahikawa city in Hokkaido in winter has very low temperature despite its situation in the middle latitude zone, and frequent ground inversion, since it is located in the inland.The area of pulp mills in the northeast of the city and its neighborhood is covered every norning in winter by thick smog which consits of smoke and steam originated from those mills.There are sometimes obrerved falls, of considerable intensity, of snow from the somog layer, which is named by A-Yamamoto “Factory Snow”.The present paper gives the record of the Factory Snow observed during 1967 through 1970.Though the crystal of th Factory Snow is found essentially the same as that formed through the process of the Nakaya's diagram, its formation process should of course be different.The investigation on the formation of the Factory Snow in future will be of some help for development of cloud physics, because the formation is considered to be made under the intermediate condition between natural process and laboratory process.

Cosmic Ray-Produced Radionuclides as Tracers of Atmospheric Precipitation Processes

Through recent developments in instrumental analysis it is now possible to measure with good precision the rainwater concentrations of five short-lived radionuclides which are produced by cosmic ray spallation of atmospheric argon. These measurements provide a method for studying the in-cloud nucleation times and aerosol scavenging efficiencies, and promise to provide information onshort-term processes which occur in rain and snow formation.

Quali, a Taiga Snow Formation of Ecological Importance

Quali, a Taiga Snow Formation of Ecological Importance

The natural and artificial formation of snow in the atmosphere

Experiments, both in a laboratory and in nature, are described, in which small quantities of solid carbon dioxide have been used to produce enormous quantities of Miow crystals from clouds of supercooled water droplets. The solid carbon dioxide, or any other object colder than about −39°C, converts the supercooled water droplets to tiny ice crystals which grow, by vapor exchange, and become snow crystals. The conditions under which such action may be followed by precipitation are discussed.

人工雪の生成條件について-補遺

人工雪の生成條件について-補遺

Prevention of Ice on Windscreens

THE National Advisory Committee for Aeronautics is conducting a programme of research intended to reduce the risks now attendant on aeroplane operation during icing conditions. A part of this programme is concerned with the prevention of ice on the windshield. The methods investigated involve the use of: (1) heat from an electric source, (2) heat from the engine exhaust, and (3) an alcohol‐dispensing, rotating wiper‐blade. Inasmuch as the problem of ice prevention exists in several forms, it is anticipated that several different methods may find application on the aeroplane. The obstructions of vision through a windshield may result from ice or snow formations on the exterior surface or from the formation of frost on the interior. The object of the present investigation, therefore, was to determine the extent to which the several methods could preserve vision. Observations were also made to determine the capacity of the rotating wiper‐blade to remove rain from the windshield.

The Transport of Sand by Wind

The subject of course is but a special case of the general problem of the transport of solid particles by fluids. The Reynolds' Numbers involved are of the same order, whether sand is transported by air or water, and the type of motion of the grains, and their resulting drag on the fluid, appear to be much the same, though too close a parallel should not be drawn since the density ratios of sand and fluid differ greatly in the two cases. But because of the greater simplicity of experiments with air, especially in pitot-tube velocity measurements, it is possible that new facts applicable to sand-water transportation may emerge from the study of sand-air transportation. There would appear to be a closer resemblance between the behaviour of sand in air and that of drifting snow. For instance the peculiarly solid formation of wind-slab snow which G. Seligman describes in his book, 'Snow Structure and Ski Fields,' seems to have a very exact counterpart in a certain type of sand deposit which can be reproduced experimentally. Here again much might be learnt about snow-drifting from experiments made with sand, which is a far more convenient medium. The particles dealt with are defined as hard grains small enough to be set in motion by the direct forward velocity of the fluid, but too massive to be seriously affected during their flight by the less violent velocities of the fluid's internal movements. Small particles of dust are seriously affected by these internal movements, but their behaviour is beyond the scope of this paper. As an example of the susceptibility of sand grains to wind motion, a fine grain of the size (0-25 mm. diam.) commonly found at the crests of dunes when shot into still air at a speed of 4 m./sec. (9 miles per hour), travels 20 cm. before its speed is reduced by 50 per cent. Wind-driven, the sand grains move in bounds (or in saltation 2), rising steeply into the air stream, and there being urged forward by the pressure of the wind upon them. By their weight they fall to the ground again, but with a high horizontal velocity component acquired from the air. On impact with

Formation of snow rollers

Quarterly Journal of the Royal Meteorological SocietyVolume 34, Issue 146 p. 87-96 Article Formation of snow rollers Charles Browett, Charles BrowettSearch for more papers by this author Charles Browett, Charles BrowettSearch for more papers by this author First published: April 1908 https://doi.org/10.1002/qj.49703414603AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume34, Issue146April 1908Pages 87-96 RelatedInformation

Lessons in Heat and Light

THE success of a previous work on “Heat, Light, and Sound” has led Prof. Jones to extend the two former parts, and publish them separately for the use of schools and junior classes in colleges. As an introduction to the study of experimental physics, the book cannot fail to be of great value. The principles of the subjects are very clearly stated, and the experiments from which they have been deduced are fully described. Most of the experiments may be easily performed by students, the instructions being sufficiently clear to guarantee success. Numerous arithmetical examples, partly selected from the author's “Examples in Physics,” are added at the ends of the various chapters. The physiographic bearings of the subject of heat have been brought well to the front; thus the origin of the Gulf Stream, trade winds, and the formation of rain and snow are explained. Many of the diagrams have been carefully drawn to scale, in order to give the student an idea of the dimensions of the apparatus which may be conveniently employed in performing the experiments.

On the formation of rain, hail and snow

Quarterly Journal of the Royal Meteorological SocietyVolume 12, Issue 58 p. 106-115 Article On the formation of rain, hail and snow Arthur W. Clayden, Arthur W. ClaydenSearch for more papers by this author Arthur W. Clayden, Arthur W. ClaydenSearch for more papers by this author First published: April 1886 https://doi.org/10.1002/qj.4970125813AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume12, Issue58April 1886Pages 106-115 RelatedInformation