Mass Balance Of Ice Caps Research Articles

Quantifying the Mass Balance of Ice Caps on Severnaya Zemlya, Russian High Arctic. I: Climate and Mass Balance of the Vavilov Ice Cap

Due to their remote location within the Russian High Arctic, little is known about the mass balance of ice caps on Severnaya Zemlya now and in the past. Such information is critical, however, to building a global picture of the cryospheric response to climate change. This paper provides a numerical analysis of the climate and mass balance of the Vavilov Ice Cap on October Revolution Island. Mass balance model results are compared with available glaciological and climatological data. A reference climate was constructed at the location of Vavilov Station, representing average conditions for the periods 1974–1981 and 1985–1988. The site of the station has a mean annual temperature of −16.5°C, and an annual precipitation of 423 mm water equivalent. The mass balance model was calibrated to the measured mass balance, and tested against the time-dependent evolution of the englacial temperatures (to a depth of 15 m). The mass balance model was then converted to a distributed model for the entire Vavilov Ice Cap. Model results predict the spatial distribution of mass balance components over the ice cap. Processes involving refreezing of water are found to be critical to the ice cap’s state of health. Superimposed ice makes up 40% of the total net accumulation, with the remaining 60% coming from firn that has been heavily densified by refreezing.

Quantifying the Mass Balance of Ice Caps on Severnaya Zemlya, Russian High Arctic. III: Sensitivity of Ice Caps in Severnaya Zemlya to Future Climate Change

A coupled surface mass balance and ice-flow model was used to predict the response of three ice caps on Severnaya Zemlya, Russian Arctic, to the present climate and to future climate changes as postulated by the Intergovernmental Panel on Climate Change (IPCC). Ice cap boundary conditions are derived from recent airborne geophysical surveying (Dowdeswell et al., 2002), and model inputs are constructed from available climate data. Model results indicate that, currently, the state of balance of ice caps on Severnaya Zemlya is dependent on their size. For small ice caps, such as Pioneer Ice Cap (area 199 km2), mass balance is extremely negative. Under current climate conditions, these relatively small ice caps are predicted to disappear within ∼1000 years. For larger ice caps, however, such as the Academy of Sciences Ice Cap (area 5586 km2), the accumulation zone is much larger, which results in these ice caps being approximately in balance today, but still susceptible to decay in future climate scenarios. When climate conditions are changed in the model, as predicted by the IPCC, the mass balance of all ice caps in Severnaya Zemlya is predicted to become negative within a 100 years or so. Although it is difficult to say with certainty the exact rate of decay, it is likely that ice loss from Severnaya Zemlya will contribute, over a period of a few hundred years, a rise in sea level of the order of a few centimeters.

Quantifying the Mass Balance of Ice Caps on Severnaya Zemlya, Russian High Arctic. II: Modeling the Flow of the Vavilov Ice Cap under the Present Climate

To understand how ice masses in the Russian High Arctic respond to climate change, the processes that influence their current mass balance must be evaluated. A mass balance model was coupled with an ice-flow model to determine the influence of the present climate regime on the dynamics of the Vavilov Ice Cap, October Revolution Island, Severnaya Zemlya. Model results show that the bulk of the ice cap is flowing relatively slowly, at a velocity of around 5 m a−1. However, the climate regime encourages the ice cap to migrate toward the precipitation source in the southwest. The ice cap may not, therefore, be in equilibrium with the present climate. Given that the response time of the ice cap is of the order of 1000 years, this non-equilibrium may be related to changes in climate that occurred during the Little Ice Age, when the ice cap may have been north of its present position.