Showing papers on "Antarctic sea ice published in 1969"

The Physics of Glaciers

Abstract: The transformation of snow to ice mass balance heat budget and climatology structure and deformation of ice hydraulics and glaciers glacier sliding deformation of subglacial till structures and fabrics in glaciers and ice sheets distribution of temperature in glaciers and ice sheets steady flow of glaciers and ice sheets flow of ice shelves and ice streams non-steady flow of glaciers and ice sheets surging and tidewater glaciers ice core studies.

One Thousand Centuries of Climatic Record from Camp Century on the Greenland Ice Sheet

Abstract: A correlation of time with depth has been evaluated for the Camp Century, Greenland, 1390 meter deep ice core. Oxygen isotopes in approximately 1600 samples throughout the core have been analyzed. Long-term variations in the isotopic composition of the ice reflect the climatic changes during the past nearly 100,000 years. Climatic oscillations with periods of 120, 940, and 13,000 years are observed.

Anchor Ice Formation in McMurdo Sound, Antarctica, and Its Biological Effects

Abstract: Aggregations of ice platelets accumulate below the annual sea ice (subice platelet layer) and on the bottom (anchor ice) to depths of 33 meters. Observations of ice platelets adhering to submerged lines support the conclusion that 33 meters is the lower limit for ice formation in the water column in this area. The rising anchor ice lifts epibenthic fauna and has a pronounced effect on the distribution of the epibenthic organisms.

Some comments on glacier surges in eastern Svalbard

Abstract: Between 1936 and 1938 a great amount of ice flowed out from Sorfonna (the South Ice) on the south coast of Nordaustlandet. What had been an even slope of the ice sheet in 1936 developed into a badl...

Albedo and degree of puddling of a melting cover of sea ice

Abstract: Continuous measurements of incident and reflected short-wave radiation have been obtained from 12 May to 17 June 1968 on the ice cover at Tanquary Fiord, ElIesmere Island (lat. 81 ° 25' N., long. 76° 50' W .) . The observations were made with radiometers suspended between two towers at a height of 50 ft (15 m) to sample an area large enough to be representative of the surface of the ice cover. From the start of surface melting, time-lapse photographs were taken at intervals of 3 h with a camera mounted on one of the towers at a height of 20 ft (6 m ) and slanted below the horizontal. Values are presented, for the observation period, of incident short-wave radiation, albedo, air temperature at screen height and percentage of surface covered with melt pools. It is shown that the albedo decreases linearly with increasing area of water puddles. RESUME. L'albedo et la quantitlf des mares d'eau sur la couchefondante de la glace de mer. Des m esures de radiation d 'onde courte d'incidence et d e reflection ont ete obtenues du 12 mai a u 17 juin 1968 sur la couche de glace a T a nquary Fiord, ElIesmere Island (8 10 25' N, 760 50' W ). Les observations ont ete faite. avec radiometres suspendus entre deux tours a une hauteur d e 15 m, observont ainsi une surface assez grande pour etre representative de la surface de la glace. Lorsque la surface glacee se mit a fondre, d es photographie. a intervales de 3 heures furent prises a u moyen d'une camera instalee sur l'une des tours a une hauteur de 6 m et inclinee au dessous de l'horizontale. Pour cette periode d 'observation, des valeurs de radiation d'incidence, d 'albedo, de temperature d e l'a ir, e t du pourcentage de la surface couverte de mares d'eau sont presentees. 11 est demon tree que I'a lbedo decroit linea irement avec la surface croissante des mares d 'eau. ZUSAMMENFASSUNG. Albedo ulld Wasserbedeckullg einer schmelzendell Meereisdecke. Fortlaufende Messungen der einfallenden und reflektierten kurzwelligen Strahlung wurden vom 12. Mai bis zum 17. Juni 1968 auf der Eisdecke des Tanquary Fiord, ElIesmere Island (Breite 81 ° 25 ' N, Lange 75° 50' W ) durchgefilhrt. Die Beobachtungen wurden mit Strahlungsmessgeraten vorgenommen, die zwischen zwei 15 m hohen Tilrmen aufgehangt waren und daher Werte ilber ein filr die Oberflache der Eisdecke reprasentatives Gebiet ergaben. Vom Beginn der Oberflachenschmelze an wurde der zeitliche Ablauf in 3 Stunden-Intervallen mit Photographien aus einer Kamera verfolgt, die auf einem der Tilrme in 6 m H6he montiert und unter die Horizontale geneigt war. Filr die Beobachtungsperiode werden folgende Werte vorgelegt: einfallende kurzwellige Strahlung, Albedo, Lufttemperatur in Instrumentenh6he und prozentualer Anteil der von Schmelzl6chern bedeckten Oberflache. Es wird gezeigt, dass die Albedo linear mit der Zunahme der Flache der Wassertilmpel abnimmt.

Summer Birds of the Pack Ice in the Weddell Sea, Antarctica

Abstract: SEVERE pack ice conditions have greatly limited scientific investigations in the Weddell Sea, that expanse of water east of the Antarctic Peninsula. Since the sea's discovery by the British navigator James. Weddell in 1823, it has presented a formidable obstacle to explorers and scientists alike. As participants in the 1968 International Weddell Sea Oceanographic Expedition (IWSOE), we were given an unusual opportunity to obtain information on the wildlife species frequenting this remote part of the world. Our investigations were carried out from aboard the USCGC 'Glacier,' an icebreaker capable of operating continuously in heavy pack ice, which enabled us to reach parts of the Weddell Sea never before visited by man. This venture was undertaken and financed by the United States Antarctic Research Program (USARP) of the National Science Foundation. Although our primary concern was a population study of antarctic seals, a considerable amount of time was also spent observing birds. This paper reports the occurrence, distribution, and relative density of the bird species we encountered in pack ice of the Weddell Sea during the 1968 austral summer. The information was obtained during 95 hours of census taking between 30 January and 15 March 1968. Counts were made on 35 of the expedition's 44-day cruise between 62?09' and 75?28' S and 38?07' and 60?09' W (Figure 1). Sladen and Friedman (1961), among others, revealed that considerable attention has already been given various aspects of antarctic ornithology, but Voous (1965) emphasized that details of the pelagic distribution, specific behavioral differences, and the seasonal vicissitudes of most species are still incompletely known. Szijj (1967) considered the Antarctic Convergence as the transition area between bird faunas of the southern ocean, but with much blending and mixing between truly antarctic and subantarctic species obscuring this division. According to Voous (1965), at least 33 species of birds frequent antarctic waters during the summer. Of these 17 nest on the antarctic continent (Sladen and Friedman, 1961). Little has been reported on the avifauna of the Weddell Sea, especially in areas of pack ice. Clarke (1907) summarized the findings of biologists aboard the 'Scotia' during the Scottish National Antarctic Expeditions of 1903 and 1904, and Novatti (1962) discussed the pelagic distribution of 24 species of birds in the Weddell Sea during the summers of 1955-56

The climatic effects of large-scale surges of ice sheets

Abstract: Surges in ice masses of glacier size are now well accepted in glaciology. There seems no reason why a similar phenomenon should not occur in bodies of ice as large as continental ice sheets.If a co...

Distribution and abundance of the Weddell seal in the western Ross Sea, Antarctica

Abstract: Summary The distribution and abundance of the Weddell seal (Leptonychotes weddelli Lesson) in the fast ice and pack ice of the western Ross Sea, Antarctica, were investigated during 1967 and 1968 from icebreakers and accompanying helicopters. It was estimated that there were about 50,000 Weddell seals in the western Ross Sea between Cape Adare and McMurdo Sound. Weddell seals appear to breed mainly in the fast ice along the Victoria Land coast and less frequently in some nearby areas of pack ice. Fast ice is preferred to pack ice. Most Weddell seals in the pack ice were adults. General observations on the distribution of crabeater, leopard, and Ross seals are included.

Attenuation of Sound in Sea Ice, 10–500 kHz

Abstract: Measurements of the attenuation of acoustic waves in sea ice at frequencies f between 10 kHz and 500 kHz have been made on the ice cover at Tanquary Fiord, Ellesmere Island (lat 81° 25′ N, long 76°50′ W) A horizontal transmission path at a depth of 4 ft (13 m), mid-way between the top and bottom surfaces of the ice cover, was used at ranges varying from 25 ft (76 m) to 4 ft (13 m) between piezoelectric transducers immersed in oil-filled bore holes The attenuation coefficient α was found to fit the equation a α = c 1 f+c 2 f 4 with c1 = 4·45 × 10−2 db m−1 kHz−1, and c2 = 2·18 × 10−10 db m−1 kHz−4 Over the frequency band covered, the linear term was predominant and the Rayleigh scattering term relatively insignificant

Evidence of surges on the Barnes Ice Cap, Baffin Island

Abstract: The morphology of the Barnes Ice Cap is studied on the basis of detailed topographic maps. Two anomalous areas characterized by an apparent excess of mass at lower elevations and a similar deficit ...

An advancing glacier in a recessive ice regime: Berlingske Bræ, North-West Greenland

Abstract: Greenland is receiving unprecedented international attention, both in scientific and political circles. Characterised by a central ice sheet up to 3.4 km thick (Inland Ice), numerous ice caps and hundreds of outlet glaciers debouching into the surrounding oceans, Greenland supports the second largest ice mass in the world. Analysis of glacier movements, melt rates and ice loss to the sea, provide data with which to assess mass balance changes and thereby predict global sealevel rise. Thus Greenland plays a central role in the current worldwide debate on climate change. Present-day dynamic ice loss is invariably advertised by the fast moving glaciers of western Greenland with their spectacular calf ice production, such as the ice streams around Disko Bugt reviewed by Weidick & Bennike (2007). This tends to overshadow ice stability and expansion seen in the form of stationary and advancing glaciers elsewhere in Greenland (MODIS 2009). While the seawards acceleration of glacier flow and retreat in frontal positions can be readily attributed to a shift in atmospheric and oceanic conditions (global warming), the same explanation can hardly be used for glaciers with contrasting movement histories.

Pilot study of ice drift in the Gulf of St. Lawrence

Abstract: A pilot study of ice drift has been made in the Gulf of St. Lawrence. A toroidal buoy with a radio beacon that was set out March 1, 1967, on an ice floe off the Gaspe coast drifted toward the southeast. Seven position determinations were made by the Ice Reconnaissance Aircraft, Meteorological Branch, up to March 20, when the beacon stopped transmitting. The buoy was recovered on May 7 south of the Magdalen Islands. By means of the Reed and Campbell theory, the ice drift due to the wind stress is calculated and the difference between the theoretical drift and the observed drift is assumed to result from surface current. The area between Anticosti Island and the Gaspe coast shows great variability with regard to its surface circulation, as during ice-free months. Furthermore, the analysis indicates that the internal ice stress, which is neglected in the Reed and Campbell theory, should be taken into account in future models. Hourly values of the ice drift velocity indicate that the ice floe is affected by the tidal current.

Sea Ice and Heat Budget

Abstract: Since the Apr 1957 occupation of the first long-term US drifting station on sea ice, much has been learned about the properties of sea ice as a material. Properties of large, composite sheets of natural sea ice are still to be defined, however, because of the need for accurate knowledge of strength, roughness and albedo, among other parameters. In explanation of the ice cover, studies have been made of energy fluxes, radiative fluxes, albedos, wind and water flow profiles in boundary layers, air and ice temperature profiles and evaporation of condensation. There remain unresolved and complex questions concerning the circumstances under which the present ice cover could change.

Late Glacial Origin of the Sandbanks, Webb Bay, Labrador

Abstract: SUMMARY The Sandbanks of Webb Bay, Labrador owe their origin to ice marginal conditions during the last stages of deglaciation of this section of the Labrador coast. Several phases in their evolution are recognized. Phase 1 was characterized by disintegration of the remnants of Webb Bay and Ado's Brook valley ice masses into separate local bodies with ice marginal runoff in an eastern direction. During Phase 2 the first and highest ice-dammed lake formed. Eastward ice marginal flow continued into Phase 3, when a large system of kame terraces (altitude 360 feet) formed beside the receding Webb Bay Ice. They led to new and lower ice marginal lakes in the eastern part of the Sandbanks. Phase 4 was dominated by the construction of a more extensive system of kame terraces almost 100 feet lower than those formed in Phase 3. Locally, minor moraines helped to direct runoff and control development of these newer kame terraces. In Phase 5, meltwater from the ice and runoff from the deglaciated highlands filled a large marginal lake (altitude 230 feet), which may have contributed to subglacial drainage down Port Manvers Run. Phase 6, the last of the glacial conditions associated with formation of the Sandbanks, was introduced by withdrawal of ice far enough so that the eustatically rising sea level was able to reach part of the Sandbanks. A terrace at 135 feet above sea level is believed to be the local upper marine limit. Stagnant ice still covered the floor of Hummock Valley at the western end of the Sandbanks at this time. Subsequently isostatic adjustment has lifted the last glacio-fluvial and some of the glacio-marine features above sea level.

Surface measurements of snow and ice for correlation with aircraft and satellite observations

Abstract: A NETWORK OF STATIONS FOR OBSERVING SNOW AND ICE WERE ESTABLISHED IN NORTH AMERICA, STARTING IN 1946, TO PROVIDE INFORMATION ON THE THICKNESS OF SEA, LAKE AND RIVER ICE, AND THE PROPERTIES OF SNOW COVER. IT COMPRISES OVER 100 STATIONS EXTENDING FROM THE WEST COAST OF ALASKA TO THE EAST COAST OF CANADA. RESULTS OF STUDIES USING THE DATA COLLECTED FROM THESE STATIONS SHOW THAT DISPITE AERIAL & YEARLY VARIATIONS DEFINITE PATTERNS IN THE MAGNITUDES OF THE VALUES EMERGE WHEN THEY ARE PLOTTED ON SMALL SCALE MAPS. AERIAL INFRARED AND PASSIVE MICROWAVE SYSTEMS ARE BEING STUDIED TO SEPARATE CLOUDS FROM SNOW-COVERED TERRAIN AND FOR PENETRATING CLOUDS TO OBTAIN SNOW AND ICE DATA. THE SEASONAL EXTENT OF THE EARTH'S SNOW AND ICE COVER CAN EASILY BE DETERMINED BY AIR- CRAFT AND SATELLITE RECONNAISSANCE. HOWEVER, DETERMINATION OF THE DEPTH AND PHYSICAL PROPERTIES OF SNOW COVER AND THICKNESS OF ICE ON LAKES, RIVERS, AND ALONG COAST LINES BY THESE REMOTE CENTERS IS IN AN EARLY STAGE OF DEVELOPMENT. CORRELATION OF THE REMOTE SENSING DATA WITH ACTUAL SURFACE CONDITIONS COULD BE ACCOMPLISHED THROUGH THE USE OF THE EXISTING NETWORK OF SNOW AND ICE STATIONS.

On the Structure of Ground Ice in the USA CREEL Permafrost Tunnel, Fairbanks, Alaska

Abstract: The glaciological studies were carried out on the ground ice in the USA CREEL Permafrost Tunnel, Fairbanks, Alaska, as a part of the JAPANESE ARCTIC HYDROSPHERE EXPEDITION 1968. After classification of ground ice as Ice wedge, Pond ice, Clear ice, Vein ice, the results of ice layers were described in relation to the stratigraphy of the section inside the tunnel. It was found from the fabric analysis of ice on the basis of observation by polarized light that the stereogram of the crystallographic orientation of grain of Ice wedge showed simillar characteristics to those of glacier ice.

BIRDS EYE 4-69, 26 May-15 June 1969.

Abstract: : BIRDS EYE 4-69 was a regularly scheduled Arctic Ocean ice reconnaissance mission covering the North American sector of the Arctic Basin, including its adjacent seas and the Parry Channel in the Canadian Archipelago from 26 May to 15 Jun 1969. Ice observations were made under daylight conditions. Low overcast existed during most flights, but good visibility allowed viewing of the ice pack on numerous occasions. In the Greenland Sea, extensive ice coverage as observed on BIRDS EYE 3-69 (23 March -22 April) continued to exist northwest of Iceland; however, conditions approached normal elsewhere. In Parry Channel, ice conditions since BIRDS EYE 1-69 (23 January - 7 February) improved from Baffin Bay to Resolute with little change westward. The fast ice boundary along the north Alaskan coast as well as a recurring polynya which had recently formed south of Banks Island were recorded. (Author)