bluuebunny/crossref_metadata_2025 huggingface dataset:
A 1400-Year Oxygen Isotope History from the Ross Sea Area, Antarctica
Authors: Grootes P.M. , Stuiver M. , Saling T.L. , Mayewski P.A. , Spencer M.J. , Alley R.B. , Jenssen D.
Published: September 2017

Four ice cores from the Ross Sea drainage, Antarctica, show patterns of δ18O variations on a time scale of decades to centuries over the last 1400 years without change in the long-term average δ18O. Century scale δ18O fluctuations in the two cores drilled in the Ross Ice Shelf at Station J-9 (82°23′S, 168°38′W, elevation 60 m) are highly correlated (P < 2 × 10−4). The long isotope record (>30 000 a) of the 1978 J-9 core thus represents local conditions over at least 102 m and on time scales of 100 years and longer.

Regional correlations between the J-9 δ18O records and those from Ridge BC (82°54′S, 136°40′W, elevation 509 m) and the Dominion Range (85°15′S, 166°10′E, elevation 2700 m) are barely significant (P ≈ 0.05 for J-9 '76 and Dominion Range, 580 to 1400 years ago) or absent. The failure to find clear regional isotope trends related to climate fluctuations may reflect the finding that between 1957 and 1982 the area was in the transition zone between areas with opposite temperature trends, and showed little or no temperature change. The fact that the records nevertheless show significant δ18O fluctuations highlights the need to base regional climate reconstructions on a regional suite of ice-core records.
Geostatistics in Glaciology: Implications of a Study of Scharffenbergbotnen, Dronning Maud Land, East Antarctica
Authors: Herzfeld U.C. , Holmlund P.
Published: September 2017

Geostatistical methods are applied in the analysis of radio-echo data from Scharffenbergbotnen, Dronning Maud Land, East Antarctica, in order to allow the following investigations: detailed and reliable cartography of subglacial bed topography and ice thickness, comparison of recent ice flow patterns and ice flow during earlier glacial maxima, and mass balance studies in relation to climatic changes.
The Antarctic Ice Sheet During the Last Glacial-Interglacial Cycle: A Three-Dimensional Experiment
Authors: Huybrechts Philippe
Published: September 2017

A complete three-dimensional thermo-mechanical ice-shect model for the entire Antarctic ice sheet, including an ice shelf, grounding line-dynamics and isostatic bed adjustment, is employed to simulate the response of the ice sheet during the last glacial-interglacial cycle with respect to changing environmental conditions. To do this, the Vostok temperature signal is used to force changes in surface temperature and accumulation rate and sea level prescribed by a piecewise linear sawtooth function. Model calculations started at 160 ka B.P. In line with glacial geological evidence, the most pronounced fluctuations are found in the West Antarctic ice sheet and appear to be essentially controlled by changes in eustatic sea level. Grounding occurs more readily in the Weddell Sea than in the Ross Sea and, due to the long time scales involved, the ice sheet does not reach its full glacial extent until 16 ka B.p. The concomitant disintegration of the West Antarctic ice sheet is triggered by a rise in sea level and takes around 6000 years to complete. The ice sheet then halts close to the present state and no collapse takes place. This Holocene deglaciation appears to have added 6–8 million km3 of ice to the world oceans, corresponding with an Antarctic contribution to world-wide sea level of 12–15 m.
An Apparent One-Year Lag Relationship of Heavy Snow Years Between Eurasia and North America
Authors: Iwasaki Tomohiko
Published: September 2017

The purpose of this study is to investigate the interannual variability of winter snow cover in the northern hemisphere, using the satellite-derived monthly snow cover data (NOAA/NESDIS) from 1967 to 1987. An empirical orthogonal function (EOF) analysis is made to see the typical pattern of snow cover variations during winter. EOF1, which represents about 40% of the total variance, shows concurrent snow cover patterns between Eurasia and North America. EOF2, which represents over 20% of the total variance, shows a negatively correlated pattern between the eastern and western parts of the continent in Eurasia and North America.

We examined time series of mean snow cover for key regions of the northern hemisphere to investigate variations depicted in the EOF patterns in more detail. We selected two key regions which represent continental-scale snow variation. One is the eastern part of Eurasia and the other is the western part of North America. The time series of the two key regions show an apparent one-year lag relationship of heavy snow cover years; winters with extensive snow cover over Eurasia tend to be followed by extensive snow cover over North America during the succeeding winters.
Satellite Altimetry, Semivariograms, and Seasonal Elevation Changes in the Ablation Zone of West Greenland
Authors: Lingle Craig S. , Brenner Anita C. , Zwally H. Jay
Published: September 2017

Seasonal mean changes in the surface elevation of the ablation zone of West Greenland to 72°N between spring 1985 and summer 1986 are measured using radar altimeter data from the 18-month Geosat Geodetic Mission. Semi-variograms are used to estimate the noise in the data as a function of position on the ice sheet. Mean elevation changes are computed by averaging the elevation differences measured at points where orbits ascending in latitude are later crossed by orbits descending in latitude (or the reverse), with each cross-over difference weighted in proportion to the inverse square of the noise level in the neighborhood of the cross-over point. The mean surface elevation of the ablation zone, relative to spring 1985, ranged from 1.5 ± 0.6 m lower during summer 1985 to 1.7 ± 0.4 m higher during spring 1986.
A Northern Hemisphere Volcanic Chemistry Record (1869–1984) and Climatic Implications Using a South Greenland Ice Core
Authors: Lyons W.B. , Mayewski P.A. , Spencer M.J. , Twickler M.S. , Graedel T.E.
Published: September 2017

The effect of volcanic emission of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the time period 1869–1984 with chemical analyses of approximately eight samples per year. Time series decomposition and locally weighted scatter plot smoothing techniques were used to extract long term trends from the data so that individual volcanic eruptions could be documented. A number of events identified here have been unnoticed previously and a high percentage of the major chemical signatures documenting these events is associated with large decreases in temperature in the latitudinal zone 60–90 °N. Many authors have pointed out that the amount of volcanic acids such as HCl and H2SO4 injected into the atmosphere has a very important influence on global climate, yet this volcanic input has been difficult to quantify prior to ∼1960. Our data help to alleviate this problem. These individual events can be compared to available frost tree ring data from North America, further establishing a volcanism-climatic linkage.
A Glaciochemical Survey of the Summit Region, Greenland
Authors: Mayewski P.A. , Spencer M.J. , Twickler M.S. , Whitlow S.
Published: September 2017

Spatial representativeness and an understanding of controls on chemical species distribution are essential requirements of any significant ice core investigation. Snowpit studies provide an essential tool in this process. In preparation for the central Greenland deep drilling effort a series of snowpits was sampled in detail for oxygen isotopes, major anions, major cations, total acidity and radionuclides. The results of this sampling program are used to define: (1) the chemical composition of the snow in the region, (2) the input timing and spatial distribution of major chemical species, (3) the potential dependence of species concentration on accumulation rate, and (4) the signal characteristics identifiable in the region over the last few years.
Climatic Information from the Chongce Ice Cap, West Kunlun, China
Authors: Nakawo Masayoshi , Ageta Yutaka , Jiankang Han
Published: September 2017

Shallow corings and pit studies were carried out in 1987 on the Chongce Ice Cap in the West Kunlun Mountains which lie along the southern edge of the Taklamakan Desert. Stratigraphic observations, as well as measurements of insoluble particles, chemical constituents and liquid conductivity, on the core and pit samples allowed identification of annual layers, although visible dirt layers are not always annual signals. A vertical profile of stable isotope content showed a periodic variation near the surface, strongly attenuated with depth.
The Impact of the Siberian High and Aleutian Low on the Sea-Ice Cover of the Sea of Okhotsk
Authors: Parkinson Claire L.
Published: September 2017

Comparison of monthly averaged sea-ice distributions in the Sea of Okhotsk with atmospheric pressure data during the four winters having passive-microwave sea-ice coverage from the Nimbus 5 satellite, 1973–76, revealed a strong apparent relationship between the extent of the sea-ice cover and the influence of the Siberian High atmospheric pressure system. Examination of data for the years 1978–86, having passive-microwave coverage from the Nimbus 7 satellite, reveals that the strong correspondence found for 1973–76 between Okhotsk sea-ice extents and the Siberian High was not maintained in the 1978–86 period. A weaker correspondence continued, however, between the sea ice and the combined Siberian High/Aleutian Low system. A Siberian High/Aleutian Low index was created, and the correlation coefficient between that index and sea-ice extents in the midwinter month of February is 0.97 for the 1973–76 period and 0.52 for the 1978–86 period. Primary reasons for the lack of a consistently strong monthly averaged ice/atmosphere correspondence are: the various oceanographic influences on the sea-ice cover, the failure of monthly averages to reflect fully the important shorter-term interactions between the ice and the atmosphere, and the fact that ice conditions in one month are influenced by ice conditions in previous months.
Climate and the Initiation of Maritime Ice Sheets
Authors: Payne Antony , Sugden David
Published: September 2017

The lower latitude extension of polar water during Quaternary glaciations has two opposing effects on the mass balances of adjacent maritime ice sheets. Cooler air temperatures reduce ablation and increase the fraction of precipitation falling as snow, but also lead to reduced atmospheric moisture content and reduced precipitation. The effects of these contrasting processes on ice-sheet initiation are investigated using a coupled ice-sheet-atmospheric moisture model of the Loch Lomond ice sheet in Scotland (10 000 a B.P.). There is a delicate balance between the degree of cooling required to initiate ice accumulation and that which restricts the flow of moisture over the area. At the regional scale of Scotland, the combined effects of orographic enhancement and the inherent feedback between the rising ice-surface elevation and increasing mass balance are dominant, and ice-sheet growth accelerates. Comparison of the results from models using different wind directions suggests that south-westerly winds were prevalent during the Loch Lomond glaciation in contrast to the dominant westerly winds of the present day. The modelling experiments demonstrate the sensitivity and complexity of the links between ocean surface cooling and ice-sheet growth, particularly at the early stages of a glacial cycle.
Asynchronous Coupling of Ice-Sheet and Atmospheric Forcing Models
Authors: Pollard David , Muszynski Isabelle , Schneider Stephen H. , Thompson Starley L.
Published: September 2017

Asynchronous coupling schemes between ice sheet and atmospheric forcing models are evaluated for use in long-term ice-age simulations. In these schemes the ice sheet and atmospheric forcing are run together for short synchronous periods (Ts), alternating with longer asynchronous periods (TA) during which the ice sheet is run with atmospheric information extrapolated from the previous synchronous period(s). Two simple ice-sheet models are used that predict ice thickness as a function of latitude, and the atmosphere is represented by a prescribed pattern of net annual accumulation minus ablation. The pattern is shifted vertically to represent long-term orbital variations, stochastic inter-annual weather variability and ice-sheet albedo feedback.

Several asynchronous schemes are evaluated by comparing results with those from fully synchronous runs. The best overall results are obtained using a scheme in which the forcing during each asynchronous period is linearly extrapolated from its means in the previous two synchronous periods. Differences from the synchronous results are caused primarily by poor sampling of the stochastic forcing component, which exaggerates the stochastic ice-sheet fluctuations. We examine how these errors depend on Ts and TA, and outline implications for GCM ice-age simulations.
An Isotopic Method of Estimating Conductive Heat Flux Through Antarctic First-Year Sea Ice
Authors: Souchez R. , Tison J. -L. , Jouzel J.
Published: September 2017

The deuterium concentration profile in a first-year Antarctic sea-ice cover is used to deduce a growth-rate curve, applying a previously published model. Time variations of the conductive heat flux throughout the growth period are then estimated from this growth-rate curve. Results indicate that the isotopic determination of sea ice growth rate can be considered as an alternate method for determining the conductive heat flux through a young sea-ice cover. However, there is need for a further test of the method by measuring in situ temperatures and growth rates during the formation of first-year sea ice, and by analyzing the isotopic composition of ice samples taken simultaneously along selected profiles during the growth period.
Twentieth-Century Glacier Change at Svartisen, Norway: The Influence of Climate, Glacier Geometry and Glacier Dynamics
Authors: Theakstone Wilfred H.
Published: September 2017

In the 1870s and 1880s, after a long period of cold conditions, most of the glaciers of Svartisen ended near their maximum Neoglacial limit. Subsequent changes, although principally a response to the climatic controls of mass balance, have been influenced by glacier geometry, including area/altitude relations and aspect, and by glacier dynamics. Calving has played a principal role in the decrease of size of two of the larger glaciers, Austerdalsisen and Flatisen, both of which became unstable once the grounded distal sections of their tongues lost contact with their beds. Mass balance variations reflect climatic controls of the length of the accumulation and ablation seasons, as well as changes of summer temperature. The mass balance record of Engabreen, a maritime outlet of the Vestre Svartisen ice cap, monitored since 1970 by the Norwegian Water Resources and Energy Administration, is not representative of the area as a whole: the more continental glaciers of Østre Svartisen are likely to experience negative net balances when that of Engabreen is slightly or moderately positive. However, the pattern of year-to-year changes of net balance is similar, not only for the Svartisen area as a whole, but also for a larger area.
Diverse Limiting Circulations In A Simple Ocean Box Model
Authors: Birchfield Edward , Wyant Matthew
Published: September 2017

A coupled ocean-atmosphere model is formulated, incorporating an ocean comprised of two surface and one deep-ocean boxes, horizontal and vertical mixing, a thermohaline circulation, and forcing by latitudinal differential surface heating and evaporation. Surface fluxes are determined through coupling with a two-box steady-state atmospheric energy-balance model The hydrological cycle, thermohaline circulation and latitudinal exchange rate in the atmosphere are each controlled by an independent parameter. For a weak hydrological cycle, a cold low-salinity deep-ocean equilibrium exists with deep water produced in high latitudes, resembling the modern ocean; for a strong hydrological cycle, a warm saline deep ocean is found with deep water produced in lower latitudes, similar to proposed models of a Cretaceous ocean. More complex solutions exist for an intermediate range of parameters. These include co-existence of both of the above limiting circulations as stable steady states and an oscillatory solution about the cold deep-ocean limit case. In general for this model, the cold deep-ocean case appears less stable than the warm saline deep-ocean case.
Albedo of Young and First-Year Antarctic Sea Ice
Authors: Brandt Richard , Allison Ian , Warren Stephen
Published: September 2017

Reflection of solar radiation was studied in the seasonal sea-ice zone off East Antarctica on a cruise of the Australian Antarctic Expedition, October-December 1988. Spectral and total albedos were measured for grease ice, nilas, young grey ice, grey-white ice, snow-covered ice, and open water. Spectral measurements covered the region 400–1000 nm wavelength. For ice too thin to support our weight, the radiometers were mounted at the end of a 1.5 m rod extended out the door of a helicopter or from a basket hung from the ship's crane, using a positioning and leveling rack. Corrections had to be applied to the downward radiation flux because the helicopter or the crane was in the field of view of the cosine-collector.

The fractional coverage of each of the ice types (and open water) was estimated hourly for the region near the ship, as well as the thickness of each ice type, and the snow thickness. Observations were carried out continuously during the four weeks the ship was in the ice, supplemented by occasional helicopter surveys covering larger areas. These observations, together with the radiation measurements, make possible the computation of area-average albedo for the East Antarctic sea-ice zone in spring.
Velocity Patterns and Elevations On Ice Stream B
Authors: Jackson M. , Whillans I.M.
Published: September 2017

All of the West Antarctic ice sheet draining into the Ross Ice Shelf lies on bedrock which is below sea level. This is thought to make it especially senstitive to rapid decay which could be triggered by an increase in atmospheric CO2 levels, ice stream B, one of the main outlets of the West Antarctic Ice Sheet, is thinning, possibly in response to changes in climate. However, Ice Stream C, its neighbor, is thickening.

One of the most effective ways to study ice streams is by repeat aerial photogrammetry. Thousands of velocity values and elevations are available for Ice Stream B using this technique. Two sections of the ice stream have repeat photogrammetry with control. Maps of elevations, velocity components and velocity gradients have been produced following the methods of Brecher (1986).

The area considered here is a 40 by 30 km block across a part of the ice stream. The maps show that most of the increase in longitudinal velocity occurs within about 6 km of the ice-stream margin and reaches a maximum of 460 m a-1 in the center of the stream. Strain rates in the shear margins reach 0.12 a-;1 and are an order of magnitude less in the main body of the stream.

The elevation maps show ridges and troughs. These features appear to be related to transverse velocities.
Hydrodynamic Model Of Glaciers and Ice Sheets Interacted With Ocean
Authors: Mazo V.L.
Published: September 2017

Tidewater glaciers and large ice sheets, e.g. the Antarctic ice sheet and a late-Würm Arctic ice sheet, are complex but single dynamic systems composed of terrestrial, marine and floating parts. Morphology and dynamics of the different parts are different. The terrestrial parts are convex and their dynamics are controlled by shear stress only (the longitudinal stress is zero); the floating parts are concave and their dynamics are controlled by longitudinal stress only (the shear stress is zero). To connect the different parts we should consider transitional zones where shear and longitudinal stresses are comparable.

To describe glacier and ice-sheet dynamics, longwave approximation of the first order is used. In this approximation it is impossible to connect terrestrial and floating parts dynamically, only morphologically and kinematically. It means that the first-order longwave approximation is not sufficient.

If the transitional zone between the terrestrial and floating parts is long in comparison to ice thickness (in hydrodynamics the term “weak” is used) we can do the next step in the longwave approximation to describe the single dynamical system consisting of the terrestrial and floating parts and the weak transitional zones (ice streams). It is a purely hydrodynamical approach to the problem without ad hoc hypothesis.

The presented model is a non-stationary three-dimensional hydrodynamic model of glaciers and ice sheets interacted with ocean, involving the conditions of ice continuity and dynamic equilibrium, ice rheology, and boundary conditions on the free surface (dynamic and kinematic) and on the bed (ice freezing or sliding). Longwave approximation is used to reduce the three-dimensional model to a two-dimensional one. The latter consists of (1) evolution equations for grounded and floating parts and weak transitional zones; (2) boundary conditions on the fronts (e.g. the conditions of calving); (3) equations governing the junctions of the parts (the most important junction is the grounded line) with the conditions connecting the evolution equations.
Radiation Interactions Between Cloud and Snow and Ice Masses
Authors: Ohata Tetsuo
Published: September 2017

Solar radiation is one of the most important meteorological components in the heat balance of the glaciers and other snow and ice masses. Observed solar radiation values are generally discussed in relation to altitude, landform, geographical position of the observation point and cloud. However, as surface of snow and ice masses possess high albedo, the surface global solar radiation on snow and ice masses usually shows higher value than surrounding ground which is low albedo, due to multiple reflection between surface and cloud. This is an important factor in determination of solar radiation on snow and ice masses. When this process is prominent, surface global solar radiation will depend on the size of the snow and ice masses. This process will be investigated in two parts. One is the presentation of radiation data taken on an ice cap and surrounding ground in the northwestern Tibetan plateau. Observations show that mean daily global solar radiation was 26% higher on the ice cap than on the ground: especially on cloudy days this value exceeded 50%. The second is collaboration of radiation data on snow and ice masses of previous studies: those data will be discussed from the above point of view. The size effect of snow and ice masses on surface solar radiation will be stressed.
Recent Terminus Behavior Of North Cascade Glaciers, Washington, Related To Climatic Sensitivity
Authors: Pelto Mauri S.
Published: September 2017

Since 1977 ablation-season temperature has been 1.1°C above the 1930–80 mean and winter precipitation has been 14% below the 1930–80 mean. In order to identify the effect of this climatic fluctuation on North Cascade glaciers, the North Cascade Glacier-Climate Project has monitored the terminus behavior of 107 glaciers between 1983 and 1988.

The 107 glaciers examined represent six climate sensitivity groups. Each group has a different sensitivity to the four primary climatic parameters: (1) ablation-season temperature, (2) accumulation-season precipitation, (3) summer cloud cover and (4) freezing levels during May and October precipitation events. A glacier’s sensitivity to each climatic parameter is determined by its geographic location and topographic position. Each sensitivity type has specific geographic and topographic characteristics, such as degree of radiational shading, orientation, altitude with respect to the local glaciation threshold, accumulation sources, and distance from the Cascade Crest. Accumulation sources are direct snowfall, wind drifting and avalanching.

Of the 107 glaciers examined, 91 had retreated significantly between 1983 and 1988 and three had advanced. Correlation of retreat rate and climatic sensitivity type indicates that the higher a glacier’s winter balance, the smaller the retreat rate. High-altitude accumulation zones, multiple accumulation sources and a northward orientation are all associated with higher winter balances. Retreat was greatest for glaciers with poor radiational shading, and only direct snowfall accumulation. Retreat rate was slowest for glaciers with multiple accumulation sources and a northward orientation, though not necessarily good radiational shading. Retreat rate increased with distance east of the Cascade Crest and retreat rate was high for low-altitude glaciers.
Instability Of The Global Greenhouse Gas System As A Cause Of The Ice Ages: A Low-Order Dynamical Model
Authors: Saltzman B. , Maasch K.A.
Published: September 2017

Due to the extremely low rate at which the major glacial variations occurred during the Pleistocene it is not possible to explain these variations by direct calculation of the fundamental fluxes of heat, momentum, and water mass that must be involved. Instead, we approach the problem in a more inductive manner by trying to formulate a physically plausible dynamical system, representing the net effects of these fluxes, that can account for the observed variance with a minimum number of adjustable parameters, given the known forcing due to Earth-orbital (Milankovitch) variations. Our model involves three “slow-response” variables: the global ice mass, the concentration of atmospheric greenhouse gases (notably CO2, methane, and water vapor), and a measure of the thermal-biological-chemical state of the ocean (perhaps measured by the stratification) that may control the Earth’s carbon cycle over the Pleistocene time period. These variables are connected by a nonlinear dynamical system comprised of three ordinary differential equations that can exhibit instability and free oscillatory behavior of a period close to 100 000 years (the period at which the maximum ice-age variability is found to exist in the late Pleistocene) despite relatively small external Earth-orbital forcing. We calculate the rate constants needed for the model to account for the main features of the ice variations, including the mid-Pleistocene transition from a period of low global ice mass devoid of the 100 000 year oscillation. The implied variations of the greenhouse gases over the past 150 000 years are in good agreement with the recent Vostok ice-core analyses.
Changes Of Atmospheric Methane Concentration Parallel To Climatic Changes
Authors: Stauffer B. , Oeschger H. , Schwander J.
Published: September 2017

Measurements on ice-core samples showed that atmospheric methane concentration changed with the large climatic cycles during the last two glaciations (Stauffer and others, 1988; Raynaud and others, 1988). The methane concentration is lower in cold periods and higher in warm periods. In this paper we discuss the results of CH4 measurements of samples from periods of minor climatic change, like the climatic optimum 8000 years B.P. and the Younger Dryas period about 10 000 to 11 000 years B.P.. The data are interpreted in terms of the present understanding of methane sources and sinks.
Detecting Global Change In The Arctic
Authors: Weller Gunter
Published: September 2017

Numerical models have predicted global temperature increases due to rising atmospheric CO2 levels, which should be detectable by now, but have not yet been identified in an unambiguous manner. This detection is complicated by inadequate data and by the fact that climate can be changed by factors other than CO2 increases. A systematic monitoring strategy is therefore needed to assess global change. In the Arctic, cryospheric parameters, including sea ice, snow cover, glaciers and permafrost are sensitive indicators of climate change and their monitoring by satellites and surface observations is of particular interest. Sea ice and snow cover are perhaps the most important of these parameters. They respond quickly to climate change, and in turn directly affect the climate through feedback processes; major changes in ice and snow extent and thickness can be expected as a consequence of climate change. Glaciers also respond to climatic variability by changes in their mass balance which can be monitored. Melting glaciers raise the level of the world ocean, and the glaciers of the sub-Arctic, particularly in the Alaskan coastal mountains, have been major contributors to the observed sea-level rise of about 20–30 cm over the last century. Past temperature changes are recorded in glacier ice and permafrost and techniques are now available to reconstruct past climates from these sources.

The numerical models of the CO2 greenhouse effect show the polar regions to be affected most strongly by greenhouse warming, and sea ice, snow, glaciers and permafrost should be good indicators of such a global change. The known responses and sensitivities of cryospheric parameters to climate change are reviewed, and a monitoring strategy is suggested. The Alaska SAR Facility, utilizing synthetic aperture radar from several spacecraft scheduled for launch in the 1990s, will be a key facility for collecting and analyzing climate-related satellite data. Its monitoring capabilities are briefly reviewed.
Soluble Impurities In Ice Core D-1 Of Dunde Ice Cap, China, Over The Last 500 Years
Authors: Xiaoling Wu , Jingsona Liu , Qinzhou Yang
Published: September 2017

This paper gives the preliminary results of 26 trace element measurements of ice cores from Dunde Ice Cap, China. The chemical composition of soluble impurities along ice core D-1 covering the last 500 years B P., is reported and interpreted in terms of atmospheric contributions. The dust content in ice cores of Dunde Ice Cap is 36 times higher than in Byrd Station, Antarctica. Variations of soluble elements such as Ca, Mg, Κ and Na, in Dunde Ice cores are very sensitive to climatic and environmental changes. The 25 trace elements in ice core D-1 (K, Na, Ca, Mg, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Pb, Al, Sr, Ti, V, Zn, As, Ba, Β, Li, Ρ, S, Sn) were measured. Cationicions arranged in order of content are as follows: Ca > Na > Mg > Κ > Αl > Fe > Ζn > Cu > Μn > Pb > Cr > Ni > Co > Cd etc. The content of soluble impurities has typical terrestrial features. Rock-forming elements such as Ca, Mg, Κ, Na, Si, Al, and Fe make up 99% in the core samples.

Particular attention is given to the possible impact of the so-called “pre-Industrial Revolution period” and man’s influence on the atmospheric chemistry. The spectral analysis of time series for the variation of each of the 26 contributions show a 92 year cycle that is present in the variation of all 26 ions with depth. Short-term variations, such as 23, 31, 48, 81 year cycles, are also discussed. The ice-core research program has been supported by the Chinese National Foundation of Natural Science under Grant DO125-4860011.
Effect Of Eurasian Snow Cover On Summer Climate Of The Northern Hemisphere: A GCM Study
Authors: Yasunari Tetsuzo , Kitoh Akio , Tokioka Tatsushi
Published: September 2017

Observational studies have shown that Eurasian snow-cover anomalies during winter-through-spring seasons have a great effect on anomalies in atmospheric circulation and climate in the following summer season through snow albedo feedback (Hahn and Shukla, 1976; Dey and Bhanu Kumar, 1987). Morinaga and Yasunari (1987) have revealed that large-scale snow-cover extent over central Asia in late winter, which particularly has a great effect on the circulation over Eurasia in the following season, is closely related to the Eurasian pattern circulation (Wallace and Gutzler, 1981) in the beginning of winter.

Some atmospheric general circulation models (GCM) have suggested that not only the albedo effect of the snow cover but also the snow-hydrological process are important in producing the atmospheric anomalies in the following seasons (Yeh and others, 1984; Barnett and others, 1988).

However, more quantitative evaluations of these effects have not yet been examined. For example, it is not clear to what extent atmospheric anomalies are explained solely by snow-cover anomalies. Spatial and seasonal dependencies of these effects are supposed to be very large. Relative importance of snow cover over Tibetan Plateau should also be examined, particularly relevant to Asian summer monsoon anomalies. Moreover, these effects seem to be very sensitive to parameterizations of these physical processes (Yamazaki, 1988).

This study focuses on these problems by using some versions of GCMs of the Meteorological Research Institute. The results include the evaluation of total snow-cover feedbacks as part of internal dynamics of climatic change from 12-year GCM integration, and of the effect of anomalous snow cover over Eurasia in late winter on land surface conditions and atmospheric circulations in the succeeding seasons.
Climatic Shift of the Equilibrium Line: Kuhn's Concept Applied to the Greenland Ice Cap
Authors: Ambach Walter
Published: September 2017

The shift of the equilibrium line in response to climatic disturbances is calculated for the International Glaciological Greenland Expedition (EGIG) profile of the Greenland Ice Cap. Data of heat balance studies carried out during EGIG 1959 and EGIG 1967 are used according to Kuhn’s algorithm. The following parameters are applied; the heat transfer coefficient of the sensible heat flux; the effective emissivity of the atmosphere for long wave downward radiation; a factor relating net radiation to cloudiness; the duration of the ablation season; the altitudinal temperature gradient; the altitudinal accumulation gradient.

The altitudinal shift of the equilibrium line results for the EGIG profile + 77m/°C and -4 m per 1/10 cloudiness with 35d of ablation. Changes in heat balance by formation of superimposed ice are taken into account.
Measurements of Daily Variations in the Subsurface Wetness Gradient
Authors: Denoth A. , Foglar A.
Published: September 2017

A flat condenser in strip-line technique has been developed to measure the gradient in liquid water content near the snow surface. This dielectric sensor is connected to a twin-T-bridge with an operating frequency of 27 MHz. The special design of the sensor allows the non-destructive measurement of the mean dielectric constant of underlying material at two different depths of 0 to 2 cm, and of 2 to 4 cm below the snow surface. Based on the model of Polder and van Santen, changes in the gradient of liquid water content can be calculated from measured changes in the dielectric constant in different depths; the density has to be measured separately. Results of measurements of wetness gradient with this flat capacitative sensor are given. Field measurements have been carried out in the Stubai Alps (3100 m a.s.1.) and at the Hafelekar (2256 m a.s.l.) near Innsbruck.
Snow dielectric properties: from DC to microwave X-band
Authors: Achammer TH. , Denoth A.
Published: September 2017

Broadband measurements of dielectric properties of natural snow samples near or at 0°C are reported. Measurement quantities are: dielectric permittivity, loss factor and complex propagation factor for electromagnetic waves. X-band measurements were made in a cold room in the laboratory; measurements at low and intermediate frequencies were carried out both in the field (Stubai Alps, 3300 m; Hafelekar near Innsbruck, 2100 m) and in the cold room. Results show that in the different frequency ranges the relative effect on snow dielectric properties of the parameters: density, grain-size and shape, liquid water content, shape and distribution of liquid inclusions and content of impurities, varies significantly. In the low-frequency range the influence of grain-size and shape and snow density dominates; in the medium-frequency range liquid water content and density are the dominant parameters. In the microwave X-band the influence of the amount, shape and distribution of liquid inclusions and snow density is more important than that of the remaining parameters.
Snow avalanche runout from two Canadian mountain ranges
Authors: Nixon D.J. , Mcclung D. M.
Published: September 2017

Field measurements on maximum runout from two different mountain ranges in Canada are presented and compared: the Coast Mountains in British Columbia and the Rocky Mountains. We include a statistical analysis of topographic terrain parameters such as starting zone catchment area, horizontal reach, vertical drop and relevant slope angles. Following McClung and Mears (1991), we derived a dimensionless parameter which is a measure of runout for each avalanche and we found that the runout ratios (defined below) for a given mountain range obey a Gumbel distribution consistent with previous results. In addition, we found that the runout ratios for both mountain ranges have a length-scale dependence which is potentially very important for land-use planning procedures: the mean value of the runout ratio decreases significantly as the horizontal reach increases. Together with data from other mountain ranges, our results show that path length effects will have to be incorporated when using statistical prediction methods for engineering zoning purposes.

The runout ratio is defined as the quotient of two lengths, Δx/Xβ, where Δ is the horizontal distance from the 10° point to the maximum runout position, and Xβ is the horizontal distance from the start position to the point where slope angle first declines to 10°.
Connectivity of snow particles
Authors: Itagaki K. , Lemieux G.E.
Published: September 2017

An optical system, potentially suitable for quantitative characterization of snow, was conceived and tested. The system uses a laser beam to scan a thick section of snow impregnated with an opaque medium and observes light transmission through the slab.
A computer database for falling snowflakes
Authors: Muramoto Ken-ichiro , Matsuura Kohki , Harimaya Toshio , Endoh Tatsuo
Published: September 2017

A computer-based measurement system for characteristics of snowfall is described. To measure the size and velocity of falling snowflakes quantitatively, images of snowflakes were input to an image processor and the primary data were analyzed in real time. In this process, maximum diameter in a horizontal plane and falling velocity were recorded in previously set intervals, then stored on a disk. Since a lot of data were obtained during a full winter season, data had to be processed to make up a database after an experiment. Using this database, the data of the distribution of size and velocity of snowflakes can be retrieved at anytime.

We observed snowflakes during winter months of 1986-92 in Sapporo and Toyama, which are located near the north east and middle of the Japan Sea coast respectively. The data indicate that the average size of snowflakes in Toyama was larger than that in Sapporo, while the number concentration of snowflakes in Sapporo was rather higher. The fall velocity tends to increase with increasing size of snowflakes, as observed in both areas.
Computer applications for avalanche forecasting in the United States
Authors: Tremper Bruce , Decker Rand
Published: September 2017

Avalanche hazard forecasters must evaluate a number of different important parameters which often vary markedly over time and distance. Computer applications have been developed to help the avalanche forecaster manage the complex data. These include programs which simply graph and tabulate data into easily ingested displays, database and statistical software, deterministic models of the snowpack evolution and stability, and finally, networks of avalanche information. This paper is an overview of computer software currently available in English and in use in the United States.
Development of a snow-fraction meter based on the conductometric method
Authors: Kitahara Takuo , Shirakashi Masataka , Kajio Yasuhiro
Published: September 2017

Hydraulic conveying of snow is one of the most promising techniques for snow removal from an urban area. The method for measuring the fraction of snow in a snow-water mixture flowing in a pipe is a key technique for its practical application. A new method based on the conductometric method has been developed in this study. The method was tested using a prototype snow-fraction meter in a testing apparatus and a closed pipeline system. This type of meter has the advantage of in situ measurement of a wide fraction range from zero up to packed value. The meter is capable of quick response, independent of flow velocity or snow properties and nonintrustive in flow. This paper describes the application of techniques for the development of the meter and the test results. This new method is expected to be useful for hydraulic conveying of ice particles or ice cubes, a new technology in the air-conditioning field.
The relationship between seasonal snow cover in Japan and recent climatic change
Authors: Nishimori Motori , Kawamura Ryuichi
Published: September 2017

Atmospheric circulation patterns associated with snowfall fluctuations in Japan are examined using a rotated empirical orthogonal function (EOF) analysis. We also compute correlation coefficients between the scores of EOF modes in the 500 hPa geopotential height field of the Northern Hemisphere (NH) and amounts of snowfall in Japan on annual, monthly and pentad time scales. It is found that recent variability of snowfall amount in Japan is closely related to the long-term variations of large-scale circulation patterns. It is suggested that the dominance of teleconnection patterns such as Pacific/North American (PNA) and Northern Asian (NA) are responsible for the increase of snowfall in the coastal regions of the Sea of Japan during the cold period for Japan (1977–86).
Development of an automatic, storage precipitation gauge for improved winter precipitation measurements
Authors: Wiesinger Thomas , Takami Shinichi , Ohno Hiroyuki , Yokoyama Kotaro
Published: September 2017

A high-precision, self-operating storage precipitation gauge was designed and field-tested. It consists of a cylinder-shaped container that incorporates antifreeze solution to melt snow and a quartz-crystal pressure sensor to detect mass of the contained liquid. Field trials showed performance to be at least equivalent to the Japanese standard gauge. A novel feature of the developed instrument is that it also measures a parameter related to wind speed, which is the basis for a catch correction. The instrument is simple, robust and can be battery-operated, therefore making it useful for winter precipitation measurements at sites where electric power supply is unavailable.
Influence of climatic warming on the amount of snow cover and water quality of Lake Biwa, Japan
Authors: Fushimi Hiroji
Published: September 2017

The amount of snow cover in the Lake Biwa catchment area has changed significantly from 1.9 × 1012kg in 1974 to 0.3 × 1012kg in 1979. The amount of snow cover was less in the warmer winter and when the amount of snow cover was less than 1012 kg, the average amount of snow cover in recent years, the lowest dissolved-oxygen concentration in the deep layer rapidly decreases. Climatic warming will significantly decrease the amount of snow cover in Lake Biwa catchment area and the dissolved-oxygen concentration in the deep layer of the lake, which may further enhance eutrophication of the lake.
Glacier thermal regime and suspended-sediment yield: a comparison of two high-Arctic glaciers
Authors: Hodson A. J. , Tranter M. , Dowdeswell J. A. , Gurnell A. M. , Hagen J. O.
Published: September 2017

This paper compares estimates of suspended-sediment yield and discharge from two glacier basins in Svalhard exhibiting contrasting glacial thermal regimes: Austre Brøggerbreen (~12 km2), which is almost entirely cold-based, and Finsterwalderbreen (~44 km2), dominated by warm basal ice. There are marked differences in the magnitude and temporal pattern of mean daily discharge and mean daily suspended-sediment concentration from the two glacier basins. Specific suspended-sediment yields from Finsterwalderbreen (710–2900 t km−2 a−1) were more than one order of magnitude greater than at Austre Brøggerbreen (81–110 t km−2 a−1). These differences are ascribed to the influence of thermal regime upon the meltwater drainage system and the predominant sources of suspended sediment. The potential significance of glacier thermal regime is further explored using studies from other glacier basins in Svalbard. Variations in thermal regime resulting from mass-balance adjustments since the termination of the Little Ice Age are also examined.
Effect of extension rate on terminus position, Columbia Glacier, Alaska, U.S.A.
Authors: Venteris E.R. , Whillans I.M. , Veen C.J. Van der
Published: September 2017

The relations between seasonal changes in ice speed, longitudinal extension rate and terminus position are investigated for Columbia Glacier, Alaska, over the period 1977–87. The lower reach of the glacier is studied using repeat aerial photography, which extends from the terminus to the base of an icefall about 14 km up-glacier. There are regular seasonal cycles in speed and stretching rate. These cycles continue after the glacier retreats off the shoal at the end of the fjord (in about 1983), indicating that factors other than backstress, such as seasonal changes in subglacial water, control the speed of the glacier. Terminus position appears to be linked with thinning induced by longitudinal extension, as predicted by the calving model proposed by Van der Veen (1996).
Equilibrium line and mean annual mass balance of Finsterwalderbreen, Spitsbergen, determined by in situ and laboratory gamma-ray measurements of nuclear test deposits
Authors: Pinglot J. F. , Pourchet M. , Lefauconnier B. , Creseveur M.
Published: September 2017

In order to determine the equilibrium line (EL) and the annual net mass balance over the accumulation area of Finsterwalderbreen, Spitsbergen, Svalbard (by detection of the 1962–63 radioactive peak from the 1961–62 atmospheric nuclear tests), we collected 14 ice cores, at elevations of 445–730 m, in the springs of 1994 and 1995. The corresponding samples were melted and filtered for laboratory gamma spectrometry. In the accumulation area, the 1962–63 radioactive layer is found well below the surface. The mean annual accumulation is not invariably related to altitude. The EL, averaged to 545 in a.s.l., leads to an accumulation area ratio of 0.3 and indicates a strong negative balance. The 584 Bq m−2 mean137 Cs deposition rate (1954–74 nuclear tests) for eight ice cores in the accumulation area is nearly twice the 340 Bq m−2 mean Svalbard value obtained from six other glaciers (at time of deposition).

An in situ gamma-ray detector was lowered down each borehole, and137 Cs levels were recorded. The counting rate is proportional to the apparent deposition rate and the specific activity. The laboratory measurements perfectly match the in situ determinations. In the ablation area, a dust layer and the associated nuclear test deposits are concentrated close to the bare ice surface of the glacier, under the winter snow layer and present maximum 137 Cs and 210 Pb contents. The dust layer acts like a filter for radioactive materials removed from the glacier and its basin by melting and water flow. The original specific activities and deposition rates at a given location are enhanced by adsorption of additional radioactivity on the dust particles. A linear relationship exists between 137 Cs and 210 Pb deposition rates. This process is almost constant for all studied ice cores. The apparent 137 Cs deposition rate for seven ice cores in the ablation area is 465 Bq m−2 (at date of measurement: 1 July 1995).