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BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

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Optical matching of ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) satellite image pairs is used to determine the surface velocities of major glaciers across the central Karakoram. The ASTER images were acquired in 2006 and 2007, and cover a 60×120km region over Baltoro glacier, Pakistan, and areas to the north and west. The surface velocities were compared with differential global position system (GPS) data collected on Baltoro glacier in summer 2005. The ASTER measurements reveal fine details about ice dynamics in this region. For example, glaciers are found to be active over their termini even where they are very heavily debris-covered. The characteristics of several surge-type glaciers were measured, with terminus advances of several hundred meters per year and the displacement of trunk glaciers as surge glaciers pushed into them. This study is the first synthesis of glacier velocities across this region, and provides a baseline against which both past and future changes can be compared.

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Glaciers in the Himalaya are often heavily covered with supraglacial debris, making them difficult to study with remotely-sensed imagery alone. Various methods such as band ratios can be used effectively to map clean-ice glaciers; however, a thicker layer of debris often makes it impossible to distinguish between supraglacial debris and the surrounding terrain. Previously, a morphometric mapping approach employing an ASTER-derived digital elevation model has been used to map glaciers in the Khumbu Himal and the Tien Shan. This study on glaciers in the Greater Himalaya Range in Zanskar, southern Ladakh, aims (i) to use the morphometric approach to map large debris-covered glaciers; and (ii) to use Landsat and ASTER data and GPS and field measurements to document glacier change over the past four decades. Field work was carried out in the summers of 2008. For clean ice, band ratios from the ASTER dataset were used to distinguish glacial features. For debris-covered glaciers, topographic features such as slope were combined with thermal imagery and supervised classifiers to map glacial margins. The method is promising for large glaciers, although problems occurred in the distal and lateral parts and in the fore field of the glaciers. A multitemporal analysis of glaciers in Zanskar showed that in general they have receded since at least the mid-to late-1970s. However, some few glaciers that advanced or oscillated -probably because of specific local environmental conditions -do exist.