Rakesh Bhambri

Glacier changes in the Garhwal Himalaya, India, from 1968 to 2006 based on remote sensing

Glacier outlines are mapped for the upper Bhagirathi and Saraswati/Alaknanda basins of the Garhwal Himalaya using Corona and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite images acquired in 1968 and 2006, respectively. A subset of glaciers was also mapped using Landsat TM images acquired in 1990. Glacier area decreased from 599.9 ± 15.6 km 2 (1968) to 572.5 ± 18.0 km 2 (2006), a loss of 4.6 ± 2.8%. Glaciers in the Saraswati/Alaknanda basin and upper Bhagirathi basin lost 18.4 ± 9.0 km 2 (5.7 ± 2.7%) and 9.0 ± 7.7 km 2 (3.3 ± 2.8%), respectively, from 1968 to 2006. Garhwal Himalayan glacier retreat rates are lower than previously reported. More recently (1990–2006), recession rates have increased. The number of glaciers in the study region increased from 82 in 1968 to 88 in 2006 due to fragmentation of glaciers. Smaller glaciers ( 2 ) lost 19.4 ± 2.5% (0.51 ± 0.07% a −1 ) of their ice, significantly more than for larger glaciers (>50 km 2 ) which lost 2.8 ± 2.7% (0.074 ± 0.071 % a −1 ). From 1968 to 2006, the debris-covered glacier area increased by 17.8 ± 3.1% (0.46 ± 0.08% a −1 ) in the Saraswati/Alaknanda basin and 11.8 ± 3.0% (0.31 ± 0.08% a −1 ) in the upper Bhagirathi basin. Climate records from Mukhim (∼1900 m a.s.l.) and Bhojbasa (∼3780 m a.s.l.) meteorological stations were used to analyze climate conditions and trends, but the data are too limited to make firm conclusions regarding glacier–climate interactions.

Glacier mapping: a review with special reference to the Indian Himalayas:

This paper deals with the development of glacier mapping and glacier fluctuations since the mid-nineteenth century, with special reference to the Indian Himalayas, and the contributions of the Survey of India and the Geological Survey of India. In addition, it presents a review of the limitations and challenges relating to: the mapping of clean-ice and debris-covered glaciers; the comparison of different data sets; and the measurement of glacier volume changes based on multitemporal digital elevation models. Possible solutions are discussed, and the emerging areas of glacier mapping research and applications for the Indian Himalayas are highlighted.

Influence of debris cover and altitude on glacier surface melting: a case study on Dokriani Glacier, central Himalaya, India

Abstract Most of the central Himalayan glaciers have surface debris layers of variable thickness, which greatly affect the ablation rate. An attempt has been made to relate debris-cover thickness to glacier surface melting. Thirty stakes were used to calculate ablation for debris-covered and clean ice of Dokriani Glacier (7 km2) from 2009/10 to 2012/13. Our study revealed significant altitude-wise difference in the rate of clean and debris-covered ice melting. We found a high correlation (R 2 = 0.92) between mean annual clean-ice ablation and altitude, and a very low correlation (R 2 = 0.14) between debris-covered ice melting and altitude. Debris-covered ice ablation varies with variation in debris thickness from 1 to 40 cm; ablation was maximum under debris thicknesses of 1–6 cm and minimum under 40 cm. Even a small debris-cover thickness (1–2 cm) reduces ice melting as compared to that of clean ice on an annual basis. Overall, debris-covered ice ablation during the study period was observed to be 37% less than clean-ice ablation. Strong downwasting was also observed in the Dokriani Glacier ablation area, with average annual ablation of 1.82 m w.e. a–1 in a similar period. Our study suggests that a thinning glacier rapidly becomes debris-covered over the ablation area, reducing the rate of ice loss.

Four decades of glacier mass balance observations in the Indian Himalaya

Understanding the glacier mass balance is necessary to explain the rate of shrinkage and to infer the impact of climate change. The present study provides an overview of the glacier mass balance records by glaciological, geodetic, hydrological and accumulation-area ratio (AAR) and specific mass balance relationship methods in the Indian Himalaya since 1970s. It suggests that the mass balance measurements by glaciological methods have been conducted for ten glaciers in the western Himalaya, four glaciers in the central Himalaya and one in the eastern Himalaya. Hydrological mass balance has been conducted only on Siachen Glacier from 1987 to 1991. Geodetic method has been attempted for the Lahaul–Spiti region for a short time span during 1999–2011 and Hindu Kush–Karakoram–Himalaya region from 2003 to 2008. We compared in situ specific balance data series with specific mass balance derived from AAR and specific mass balance relationship. The results derived from existing and newly presented regression model based on AAR and specific mass balance relationship induced unrealistic specific mass balance for several glaciers. We also revised AAR0 and ELA0 based on available in situ AAR and specific mass balance data series of Indian Himalayan glaciers. In general, in situ specific and cumulative specific mass balance observed over different regions of the Indian Himalayan glaciers shows mostly negative mass balance years with a few positive ones during 1974–2012. On a regional level, the geodetic studies suggest that on the whole western, the central and the eastern Himalaya experienced vast thinning during the last decade (2000s). Conversely, Karakoram region showed slight mass gain during almost similar period. However, the glaciological, hydrological and geodetic mass balance data appear to exhibit short time series bias. We therefore recommend creation of benchmark glaciers network for future research to determine the impact of climate change on the Himalayan cryosphere.

Surge-type and surge-modified glaciers in the Karakoram

Glaciers in the Karakoram exhibit irregular behavior. Terminus fluctuations of individual glaciers lack consistency and, unlike other parts of the Himalaya, total ice mass remained stable or slightly increased since the 1970s. These seeming anomalies are addressed through a comprehensive mapping of surge-type glaciers and surge-related impacts, based on satellite images (Landsat and ASTER), ground observations, and archival material since the 1840s. Some 221 surge-type and surge-like glaciers are identified in six main classes. Their basins cover 7,734 ± 271 km2 or ~43% of the total Karakoram glacierised area. Active phases range from some months to over 15 years. Surge intervals are identified for 27 glaciers with two or more surges, including 9 not previously reported. Mini-surges and kinematic waves are documented and surface diagnostic features indicative of surging. Surge cycle timing, intervals and mass transfers are unique to each glacier and largely out-of-phase with climate. A broad class of surge-modified ice introduces indirect and post-surge effects that further complicate tracking of climate responses. Mass balance in surge-type and surge-modified glaciers differs from conventional, climate-sensitive profiles. New approaches are required to account for such differing responses of individual glaciers, and effectively project the fate of Karakoram ice during a warming climate.

Hydroclimatic significance of stable isotopes in precipitation from glaciers of Garhwal Himalaya, Upper Ganga Basin (UGB), India

Centre for Glaciology, Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun 248001, India Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721302, India Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun 248001, India School of Environment and Natural Resources, Doon University, Dehradun 248001, India Correspondence Akshaya Verma, Centre for Glaciology, Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun 248001, India. Email: akshayaverma5@gmail.com

Uttarakhand Calamity: A Climate Revelation in the Bhagirathi River Valley Uttarakhand, India

On June 16 and 17, 2013, high-intensity rainfall (>400 mm) in different parts of the state of Uttarakhand caused devastating flash floods and triggered widespread landsides. In this event incurred heavy losses to the infrastructure, agricultural fields, human and animal lives, roads and widespread destruction of natural resources. Disaster of such a magnitude of disaster was perhaps not experienced by the region at least over the last 100 years. Thus, this disaster can be considered as an extreme climatic event of the century. The extent and intensity of the tragedy can easily be visualised by the fact that all the famous shrines of the Uttarakhand state are located in high mountainous, snowbound areas. These places, Badrinath (3133 m asl in Alaknanda valley), Kedarnath (3584 m asl in Mandakini valley), Gangotri (3140 m asl in Bhagirathi valley), Yamunotri (3291 m asl in Yamuna valley) and Hemkund Sahib (4433 m asl in Alaknanda valley), were badly affected by this extreme fury of the nature.

Reconstructing the pattern of the Bara Shigri Glacier fluctuation since the end of the Little Ice Age, Chandra valley, north-western Himalaya

The pattern of glacial records since the end of the Little Ice Age (LIA) are essential for evaluating glacier fluctuations and their link to post-LIA climate change. Although recession of the Himalayan glaciers is well-documented in this period, debate continues as to the magnitude and accuracy of estimated recession rates. This study presents a reconstruction of the pattern of fluctuations at the Bara Shigri Glacier in the Himachal Himalaya during the termination of the LIA (∼1850). A multi-data integrative analysis (MDIA) technique consisting of repeat terrestrial photographs, historical archives and reports, geomorphological evidence and maps, and high to medium spatial resolution satellite images (Corona, Hexagon, Landsat and WorldView-2) was used with supplemented by extensive field validation. The results indicate that during the early part of the 19th century the terminus of Bara Shigri Glacier was at ∼3900 m asl. Following this, there was a continuous recession with a total retreat of 2898 ± 50 m, which corresponds to a frontal areal loss of 4 ± 1 km2 in the last 151 years (1863–2014). Compared to this, during the last half century (1965–2014), the glacierised area was reduced by 1.1 ± 0.02 km2 with a concomitant terminus retreat of 1100 ± 32 m. The early 19th century advance is ascribed to a combination of cooling during this period, glacier topographical characteristics and contributions from steep-fronted avalanching tributaries. The late 19th century recession can be attributed to an overall increase in the temperature with a corresponding decrease in precipitation in the north-western Himalaya. Results are at variance with earlier, larger estimates of the frontal area loss for the Bara Shigri Glacier using either Survey of India (SoI) topographic maps or coarse spatial resolution satellite images (e.g. Landsat MSS) as historical datasets, and demonstrate the utility of mixed method approaches including higher-resolution satellite imagery for accurate estimation of glacier behaviour in this region.