Sea Ice Shelf Research Articles

Extreme ecosystems and geosystems in the Canadian High Arctic: Ward Hunt Island and vicinity

Global circulation models predict that the strongest and most rapid effects of global warming will take place at the highest latitudes of the Northern Hemisphere. Consistent with this prediction, the Ward Hunt Island region at the northern terrestrial limit of Arctic Canada is experiencing the onset of major environmental changes. This article provides a synthesis of research including new observations on the diverse geosystems/ecosystems of this coastal region of northern Ellesmere Island that extends to latitude 83.11° N (Cape Aldrich). The climate is extreme, with an average annual air temperature of -17.2 °C, similar to Antarctic regions such as the McMurdo Dry Valleys. The region is geologically distinct (the Pearya Terrane) and contains steep mountainous terrain intersected by deep fiords and fluvial valleys. Numerous glaciers flow into the valleys, fiords, and bays, and thick multi-year sea ice and ice shelves occur along the coast. These extreme ice features are currently undergoing rapid attrition. The polar desert landscape contains sparse, discontinuous patches of vegetation, including dense stands of the prostrate shrub Salix arctica (Artic willow) at some sites, and 37 species of vascular plants on Ward Hunt Island. Diverse aquatic ecosystems occur throughout the area, including meromictic, epishelf, and perennially ice-covered lakes. Many of these have responded strongly to climate shifts in the past and like other geosystems/ecosystems of the region are now sentinels of ongoing global climate change.

A Theoretical and Measurement Study of Sea Ice and Ice Shelf in Antarctica as Electrically Dense Media

Due to Antarctica's remoteness and harsh weather condition, remote sensing technology has been an attractive tool in equipping Antarctica scientists with the monitoring information and the understanding of ice physical changes in the Antarctican ecological system. Previous Antarctica researches on remote sensing of ice mainly utilize ice and snow scattering models based on independent scattering assumption. The needs of the consideration of coherent effects of the scatterers and the measurement of physical parameters affecting such effects are addressed in this study. Theoretical model based on radiative transfer theory with the incorporation of Dense Medium Phase and Amplitude Correction Theory (DM-PACT) [1] is developed. This concept of DM-PACT derived from antenna array theory requires an understanding of the distribution statistics of the scatterers in the homogeneous host medium. The ground truth measurement of multi-year period has been conducted at sea ice and ice shelf areas near Scott Base, Ross Island in Antarctica and a series of measurement of sea ice and snow physical parameters including distribution statistics of the air bubbles in sea ice are carried out. Theoretical study of the backscattering returns and scattering mechanisms in these electrically dense media is performed and analysis of important physical parameters affecting the radar returns is presented. Satellite measurements of the test areas from Radarsat have been acquired for the comparison of model predictions and measurement data with promising results.

Major features of the distribution of coal‐bearing deposits in Antarctica

Abstract The authors have attempted to assess the potential coal reserves of Antarctica. Several coal‐bearing sedimentary basins are located around the margins of the East Antarctic Platform. The most extensive coal‐bearing deposits, Permian and Triassic in age, are located in the Transantarctic Mountains, where they extend for 2500 km from Victoria Land to the Horlick Mountains. Another significant basin, Permian in age, is that in the Prince Charles Mountains. The authors present a detailed description of the stratigraphy of the coal‐bearing sequences in each of these major basins. Estimates of reserves are as follows: 10.8 billion tons in the Prince Charles Mountains; 6 billion tons in the Queen Alexandra Range in the Transantarctic Mountains, and 130 million tons in southern Victoria Land, also in the Transantarctic Mountains. Some information is also provided on minor coal‐bearing deposits located in the nunataks around the Weddell Sea and Filchner Ice Shelf.