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This study investigates spatial patterns in glacier characteristics and area changes at decadal scales in the eastern Himalaya - Nepal (Arun and Tamor basins), India (Teesta basin in Sikkim) and parts of China and Bhutan - based on various satellite imagery: Corona KH4 imagery, Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Advanced Spaceborne Thermal Emission Radiometer (ASTER), QuickBird (QB) and WorldView-2 (WV2). We compare and contrast glacier surface area changes over the period of 1962-2000/2006 and their dependency on glacier topography (elevation, slope, aspect, percent debris cover) and climate (solar radiation, precipitation) on the eastern side of the topographic barrier (Sikkim) versus the western side (Nepal). Glacier mapping from 2000 Landsat ASTER yielded 1463±88 km2 total glacierized area, of which 569±34 km2 was located in Sikkim and 488±29 km2 in eastern Nepal. Supraglacial debris covered 11% of the total glacierized area, and supraglacial lakes covered about 5.8% of the debris-covered glacier area alone. Glacier area loss (1962 to 2000) was 0:50±0:2%yr-1, with little difference between Nepal (0:53±0:2%yr -1) and Sikkim (0:44±0:2%yr-1). Glacier area change was controlled mostly by glacier area, elevation, altitudinal range and, to a smaller extent, slope and aspect. In the Kanchenjunga–Sikkim area, we estimated a glacier area loss of 0:23±0:08%yr-1 from 1962 to 2006 based on high-resolution imagery. On a glacier-by-glacier basis, clean glaciers exhibit more area loss on average from 1962 to 2006 (34 %) compared to debris-covered glaciers (22 %). Glaciers in this region of the Himalaya are shrinking at similar rates to those reported for the last decades in other parts of the Himalaya, but individual glacier rates of change vary across the study area with respect to local topography, percent debris cover or glacier elevations. [ABSTRACT FROM AUTHOR]

In the Everest region, Nepal, ground-based monitoring programmes were started on the debris-free Mera Glacier (27.7° N, 86.9° E; 5.1 km2, 6420 to 4940m a.s.l.) in 2007 and on the small Pokalde Glacier (27.9° N, 86.8° E; 0.1 km2, 5690 to 5430ma.s.l., ~25 km north of Mera Glacier) in 2009. These glaciers lie on the southern flank of the central Himalaya under the direct influence of the Indian monsoon and receive more than 80% of their annual precipitation in summer (June to September). Despite a large interannual variability with glacier-wide mass balances ranging from -0.67±0.28m w.e. in 2011-2012 (Equilibriumline altitude (ELA) at -5800ma.s.l.) to ∔0.46±0.28m w.e. in 2010-2011 (ELA at ~5340ma.s.l.), Mera Glacier has been shrinking at a moderate mass balance rate of -0.08±0.28m w.e. yr-1 since 2007. Ice fluxes measured at two distinct transverse cross sections at -5350ma.s.l. and -5520m a.s.l. confirm that the mean state of this glacier over the last one or two decades corresponds to a limited mass loss, in agreement with remotely-sensed regionwide mass balances of the Everest area. Seasonal mass balance measurements show that ablation and accumulation are concomitant in summer which in turn is the key season controlling the annual glacier-wide mass balance. Unexpectedly, ablation occurs at all elevations in winter due to wind erosion and sublimation, with remobilised snow potentially being sublimated in the atmosphere. Between 2009 and 2012, the small Pokalde Glacier lost mass more rapidly than Mera Glacier with respective mean glacier-wide mass balances of -0.72 and -0.23±0.28m w.e. yr-1. Low-elevation glaciers, such as Pokalde Glacier, have been usually preferred for in-situ observations in Nepal and more generally in the Himalayas, which may explain why compilations of ground-based mass balances are biased toward negative values compared with the regional mean under the present-day climate. [ABSTRACT FROM AUTHOR]

The recent evolution of Pamir-Karakoram- Himalaya (PKH) glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To estimate the region-wide glacier mass balance for 9 study sites spread from the Pamir to the Hengduan Shan (eastern Himalaya), we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008- 2011) DEMs derived from SPOT5 stereo imagery. During the last decade, the region-wide glacier mass balances were contrasted with moderate mass losses in the eastern and central Himalaya (-0.22±0.12mw.e. yr-1 to -0.33±0.14mw.e. yr-1) and larger losses in the western Himalaya (-0.45±0.13mw.e. yr-1). Recently reported slight mass gain or balanced mass budget of glaciers in the central Karakoram is confirmed for a larger area (+0.10±0.16mw.e. yr-1) and also observed for glaciers in the western Pamir (+0.14±0.13mw.e. yr-1). Thus, the "Karakoram anomaly" should be renamed the "Pamir- Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers, -0.14±0.08mw.e. yr-1, is two to three times less negative than the global average for glaciers distinct from the Greenland and Antarctic ice sheets. Together with recent studies using ICESat and GRACE data, DEM differencing confirms a contrasted pattern of glacier mass change in the PKH during the first decade of the 21st century. [ABSTRACT FROM AUTHOR]

The volume change of the Chhota Shigri Glacier (India, 32° 20 N, 77° 300 E) between 1988 and 2010 has been determined using in situ geodetic measurements. This glacier has experienced only a slight mass loss between 1988 and 2010 (-3.8±2.0mw.e. (water equivalent) corresponding to -0.17 pm 0.09mw.e. yr-1). Using satellite digital elevation models (DEM) differencing and field measurements, we measure a negative mass balance (MB) between 1999 and 2010 (-4.8±1.8mw.e. corresponding to -0.44±0.16mw.e. yr-1). Thus, we deduce a slightly positive or near-zero MB between 1988 and 1999 (+1.0±2.7mw.e. corresponding to +0.09±0.24mw.e. yr-1). Furthermore, satellite DEM differencing reveals that the MB of the Chhota Shigri Glacier (-0.39 pm 0.15mw.e. yr-1) has been only slightly less negative than the MB of a 2110 km2 glaciarized area in the Lahaul and Spiti region (-0.44±0.09mw.e. yr-1) during 1999-2011. Hence, we conclude that the ice wastage is probably moderate in this region over the last 22 yr, with near equilibrium conditions during the nineties, and an ice mass loss after. The turning point from balanced to negative mass budget is not known but lies probably in the late nineties and at the latest in 1999. This positive or near-zero MB for Chhota Shigri Glacier (and probably for the surrounding glaciers of the Lahaul and Spiti region) during at least part of the 1990s contrasts with a recent compilation of MB data in the Himalayan range that indicated ice wastage since 1975. However, in agreement with this compilation, we confirm more negative balances since the beginning of the 21st century. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the Little Ice Age (LIA, mid-17th-early 18th century). In terms of changes in mass balance, although there have been some sporadic gains on several glaciers, we show that the trend has been quite negative over the past 50 yr, with a mean mass balance deficit for glaciers in the tropical Andes that is slightly more negative than the one computed on a global scale. A break point in the trend appeared in the late 1970s with mean annual mass balance per year decreasing from ?0.2mw.e. in the period 1964- 1975 to ?0.76mw.e. in the period 1976-2010. In addition, even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia show that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance at the decadal timescale. Precipitation did not display a significant trend in the tropical Andes in the 20th century, and consequently cannot explain the glacier recession On the other hand, temperature increased at a significant rate of 0.10 °C decade-1 in the last 70 yr. The higher frequency of El Niño events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may thus explain much of the recent dramatic shrinkage of glaciers in this part of the world. [ABSTRACT FROM AUTHOR]

The article offers information on the study conducted by the authors related to the association of glacier annual mass balance and glacier albedo retrieved from Moderate Imaging Spectroradiometer (MODIS) data. It states that the accuracy of the retrieved albedo is estimated using both field measurements, at two automatic weather stations located on the glacier, and albedo values derived from terrestrial photographs.

The article presents a study which examines the temporal and spatial variations of surface albedo on Saint Sorlin Glacier in French Alps, France. The study develops a method of retrieving the albedo of frozen surfaces using terrestrial photography during the summers 2008 and 2009. The results of the study reveal the factors contributing to the variability of the albedo of glaciers including size and shape of the ice grains, surface roughness and content of impurities.

A major proportion of flow in the Indus River is contributed by its snow- and glacier-fed river catchments situated in the Himalaya, Karakoram and Hindukush ranges. It is therefore essential to understand the cryosphere dynamics in this area for water resource management. The MODIS MOD10A2 remote-sensing database of snow cover products from March 2000 to December 2009 was selected to analyse the snow cover changes in the Hunza River basin (the snow- and glacier-fed sub-catchment of the Indus River). A database of daily flows for the Hunza River at Dainyor Bridge over a period of 40 yr and climate data (precipitation and temperature) for 10 yr from three meteorological stations within the catchment was made available to investigate the hydrological regime in the area. Analysis of remotely sensed cryosphere (snow and ice cover) data during the last decade (2000-2009) suggest a rather slight expansion of cryosphere in the area in contrast to most of the regions in the world where glaciers are melting rapidly. This increase in snow cover may be the result of an increase in winter precipitation caused by westerly circulation. The impact of global warm- ing is not effective because a large part of the basin area lies under high altitudes where the temperature remains negative throughout most of the year. [ABSTRACT FROM AUTHOR]

Abstract: A complete and detailed map of the ice-velocity field on mountain glaciers is obtained by cross-correlating SPOT5 optical images. This approach offers an alternative to SAR interferometry, because no present or planned RADAR satellite mission provides data with a temporal separation short enough to derive the displacements of glaciers. The methodology presented in this study does not require ground control points (GCPs). The key step is a precise relative orientation of the two images obtained by adjusting the stereo model of one “slave”'' image assuming that the other “master” image is well georeferenced. It is performed with numerous precisely-located homologous points extracted automatically. The strong ablation occurring during summer time on the glaciers requires a correction to obtain unbiased displacements. The accuracy of our measurement is assessed based on a comparison with nearly simultaneous differential GPS surveys performed on two glaciers of the Mont Blanc area (Alps). If the images have similar incidence angles and correlate well, the accuracy is on the order of 0.5 m, or 1/5 of the pixel size. Similar results are also obtained without GCPs. An acceleration event, observed in early August for the Mer de Glace glacier, is interpreted in term of an increase in basal sliding. Our methodology, applied to SPOT5 images, can potentially be used to derive the displacements of the Earth''s surface caused by landslides, earthquakes, and volcanoes. [Copyright &y& Elsevier]