The East Antarctic sea-ice zone : ice characteristics and drift
In this paper sea ice interactions with atmosphere and ocean are illustrated by a summary of results from process studies over land-fast ice near Mawson, Antarctica. New data are then presented on the drift and characteristics (particularly ice type
and ice thickness) of the pack ice in the Indian Ocean sector of the Southern Ocean.
The basal ice and debris sequence at the margin of an equatorial ice cap| El Cotopaxi, Ecuador
This paper describes the basal ice sequence observed at the margins of two glaciers descending from the ice cap of El Cotopaxi, an active volcano, and considers the implications of these observations for the understanding of basal ice processes
Continental ice sheets and the planetary radiation budget
The interaction between continental ice sheets and the planetary radiation budget is potentially important in climate-sensitivity studies. A simple ice-sheet model incorporated in an energy-balance climate model provides a tool for studying
this interaction in a quantitative way. Experiments in which the ice-sheet model is coupled step by step to the climate model show that ice sheets hardly affect the zonal mean radiation balance because the albedo feedback due to sea ice and snow cover is dominating
. The model requires a 5% drop in the solar constant to create ice sheets of ice-age size. If the feedback between surface elevation and ice-mass balance is included (in very crude way), the ice-sheet size (L, mesured southward from 70N) becomes much more
sensitive to insolation. For a range of normalized solar constants, roughly from 0.98 to 1.02, two stable solutions exist: L0 and L2000 km. This result demonstrates that the response of ice sheets to insolation variations is far from linear. It also stresses
the need for explicit modeling of the ice-mass balance of ice sheets, particularly its dependence on surface elevation.
The A. reviews various prescriptions and parameterizations for snow and ice albedo which have been employed in sea-ice model simulations. Sea-ice albedo is also briefly discussed in terms of its interactions with ice thickness and atmospheric
conditions (radiation balance, clouds) in modelled atmospheres. Some recommendations for improving sea-ice albedo representation in numerical models are proposed.
Examples of ice pack rigidity and mobility characteristics determined from ice motion
A method has been developed to determine ice pack rigidity and mobility using observed ice motion. Using this method, one may determine how solidly the ice pack is frozen in near real-time. Various degrees of ice rigidity are considered using
remotely-sensed ice motion off the N coast of Alaska during 1975 and 1979.
Identification of annual layers in superimposed ice from Storoyjokulen in northeastern Svalbard
This pilot study shows that the identification of summer surfaces in superimposed ice is possible on ice caps like Storoyjokulen which, in turn, means that the dating of this ice is possible.
The Antarctic ice sheet : an analog for Northern hemisphere paleo-ice sheets? in Models in geomorphology.
How glaciological processes can interact to control global ice-sheet fluctuations during a glacial cycle and where analogies with the Arctic can be drawn.
A distinction between ice-pushed and ice-lifted landforms on lacustrine and marine coasts
The distinction between the processes of ice push, and ice lifting and rafting is made in this work from a study of the occurrence of boulder barricades in a small lake, Second Roach Pond, in northern Maine. A classification of shoreline features
Arctic sea-ice characteristics and associated atmosphere Ice interactions in summer inferred from SMMR data and drifting buoys : 1979-1984
SMMR-derived sea ice concentrations for November 1978-October 1984 in the Canada Basin are examined to determine temporal and spatial scales of variability in ice concentration and extent. Large regions of reduced-concentration ice are observed
. Comparison with buoy-measured surface pressure and winds suggests that reduced ice concentrations are associated with regions of strong winds and divergence beneath low pressure systems.
More on deep glacial erosion by continental ice sheets and their tongues of distributary ice
High latitude intracontinental seaways occupy great troughs carved by broad tongues of inland ice as it debouched to deep marine water. Such troughs occur in glaciated coasts, but not in stable, nonglaciated ones. Where ice flowed across them
, coasts are digitate in low relief. In the northeastern sector of the Laurentide Ice Sheet, large glacial grooves converge toward the Gulf of Boothia - Prince Regent Inlet - Lancaster Sound, suggesting that it was an exit for inland ice which shaped
Oxygen-isotope analyses and Pleistocene ice volumes
The oxygen-isotope record from fossil foraminifera in deep-sea sediments is commonly used as a proxy for global ice volume. The linkage between O and ice volume, however, is probably nonlinear. The AA. have developed a simple numerical model
of the isotopic response of the oceans to ice-volume change. They illustrate the response of their model to simple hypothetical ice-volume transitions of ice growth and ice decay. Sensitivity tests are illustrated for all model parameters. The results suggest
that oxygen-isotope records reproduce the general patterns on ice-volume change fairly accurately. The foraminiferal isotope record, however, may misrepresent the true amplitude of the ice-volume signal and lag true ice volume by 1000 to 3000 yr.
On the ice age glaciation of the Tibetan Highlands and its transformation into a 3-D model
The AA. present an interdisciplinary study on data and modeling intercomparison, concerning the possible existence of a Tibetan ice sheet and its climatological implications during the ice age.
On the value of long-term satellite passive microwave data sets for sea-ice/climate studies
With passive microwave data, global sea ice distributions can be mapped on a routine basis every few days, to a spatial resolution on the order of 30 km. The sea ice records generated so far from such satellite data have already been used, helping
to quantify global sea ice distributions and their seasonal and interannual variations, and to illuminate possible ice/ocean and ice/atmosphere interactions.
Fram Strait ice flux calculations and associated arctic ice conditions
The areal outflow of ice through Fram Strait during the period 1953-1984 is estimated on a monthly basis from the geostrophic wind and the ice concentration. Summer ice coverage in various sectors of the Arctic is then compared with the computed
outflow through Fram Strait in various antecedent periods. Lag correlations indicate that interannual variations of summer ice severity in the Pacific side of the Arctic Basin are consistent with fluctuations of Fram Strait outflow during the previous 3-9
months. The findlings suggest that above-normal outflow of multiyear ice during the winter, spring months may precondition the large-scale pack ice to respond more directly to offshore flow events during the ensuing months.
Milankovitch theory of Ice Ages: hypothesis of ice-sheet linkage between regional insolation and global climate
It is proposed that interlocked variations of ice-sheet sinks in both polar hemispheres amplified and transmitted Milankovitch summer half-year insolation changes (a version of the astronomical theory) between 45 and 75 N into the globally