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The article discusses a research study on the cyclic behaviour in the Parallel Ice Sheet Model (PISM) through numerical experiments. It describes three sets of experiments including the basal parameter experiments, the climate parameter experiments and the climate feedback experiments for identifying interactions and processes that comprise multiple types of oscillatory flow. Results showed that in the basal parameter experiments, flow enhancement was due to the interplay of water production, sliding and basal shearing with high-frequency oscillations relying on geometric interaction with water redistribution on temperate base. It also notes that the diffusive basal water model is suitable for cyclic behaviour studies.

On glacial time scales, the waxing and waning of the Eurasian and North American ice sheets depend largely on variations in atmospheric temperature. As global sea level is primarily determined by the volume of these ice sheets, there is a direct (yet complex) relation between global sea level and the northern hemispheric (NH) temperature. This relation is essentially represented by a model of the NH ice sheets. We use a thermomechanical ice-sheet-ice shelf-bedrock model in conjunction with an inverse method to deduce a time series of NH temperature (from 120 kyr BP until present) that is consistent with the observed global sea level record. The advantage of this method is that it provides the annual mean surface air temperature averaged over the NH continents north of 40°N. The results reveal that ice age temperatures were 4-10°C lower than today, which agrees with other temperature reconstructions. However, reconstructed temperatures are comparitively low during the early stages of the glacial, a feature that is consistent with the rapid growth of the ice sheets. The sensitivity of the results for uncertainties in precipitation rate, in observed sea level and in some other model parameters is examined to quantify the error in reconstructed temperature. During the glacial period (120-15 kyr BP), surface air temperatures in the NH (north of 40°N) were 7.2±1.5°C lower than today’s (interglacial) temperatures. [ABSTRACT FROM AUTHOR]

Investigates the surface energy balance (SEB) of the Greenland ice sheet for the summer ablation season of 1998. Discussion of the SEB; Factors that influence the SEB and surface mass balance of the ice sheet; Details on a study that examined the sensitivity of the SEB components.

Uses a 14 year integration with a regional atmospheric model to obtain detailed information on the Antarctic surface mass balance and to understand the mechanisms responsible for the spatial and temporal distribution of the surface mass balance. Sea surface temperature and sea ice extent are prescribed from observations. Generally, good agreement is found between model output and measurements, although in the interior of the ice sheet the temperatures are slightly too high in summer. A statistical relation between precipitation and topographical parameters is derived from model output. Half of the spatial variance in precipitation can be explained by a relation between precipitation and distance to the coast. In the interior of the ice sheet, seasonality of precipitation is mainly determined by temperature, but, near the coast, the dynamics of the flow are important.Year-to-year variations in seasonality of precipitation are large and might affect proxies for meteorological variables in ice cores.

Reports on a workshop held during the Climate Conference in August 2001 at Utrecht University in the Netherlands regarding the katabatic flows over glaciers and ice sheets. Effects of turbulence on the glacier surface and atmosphere; Reasons behind the existence of katabatic flows; Discussion on the spatial scale of glaciers.