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The extent of snow cover on the earth is considered an important parameter for numerous climatological and hydrological applications. Snow cover dynamics in mountainous regions is a vital input for energy balance, glacier mass balance, climate change and snowmelt runoff modelling. There have been global efforts for monitoring of snow cover of earth at varying spatial and temporal scales by generation of snow products. Among these, one of the high temporal and spatial resolution datasets has been generated using advanced wide field sensor data for Western and West-Central Himalayan region at the Space Applications Centre, Ahmedabad. This is done using an algorithm developed based on normalized difference snow index. This paper discusses the trends of snow cover from 2004 to 2014 based on an input of approximately 12,600 snow cover products at sub-basin scale in Indus, Chenab, Satluj and Ganga basins. Analysis of snow cover shows high variability during accumulation than in ablation period. A subtle increase in snow cover was observed in all basins during 2004-2014. [ABSTRACT FROM AUTHOR]

Therapeutic potential of medicinal plants as a source of noble natural anti-oxidants and anti-microbial agents has been well recognised all across the globe. In this study, phenolic compounds, in vitro anti-oxidant activity and anti-microbial properties have been investigated in five Himalayan medicinal plants, (e.g., Acorus calamus, Habenaria intermedia, Hedychium spicatum, Roscoea procera and Valeriana jatamansi) in different solvent systems. R. procera exhibited significantly ( p < 0.05) higher phenolics; while H. spicatum was rich in flavonoids and V. jatamansi in anti-oxidant activity. Also, R. procera and H. spicatum were found rich in gallic acid; V. jatamansi in catechin, hydroxylbenzoic acid and caffeic acid and H. intermedia in hydroxyl benzoic acid. Solvent systems showed species specific response for extraction of total flavonoids and anti-oxidant activity. All the extracts were found effective against different bacterial and fungal strains in a dose dependent manner and maximum antimicrobial activity was found in R. procera as compared to other species. All the plant extracts showed greater activity against bacterial strains as compared to fungal strains. The results of this study suggest that extract of these species can be used as natural anti-oxidant to reduce free radical mediated disorders and as natural alternative for food preservation. [ABSTRACT FROM AUTHOR]

Satellite photogrammetric technique has been used for monitoring of fluctuations of Himalayan glaciers and the resulting changes in the elevations of glacier snouts. Two across-track stereo pairs from the Indian Remote Sensing Satellite (IRS)-1C covering parts of Basapa valley, a high altitude Himalayan glaciated terrain, were processed for generation of digital elevation models (DEM) and orthoimages using a softcopy photogrammetry workstation. Two glacier regions, viz., Janapa Garang and Shaune Garang glacier valley, were taken up for the study. For one glacier region, the stereo pair was generated in a workstation by replacing an image of one pair with an image from the other pair. Interchanging input image and reference image in the new pair has resulted in improvement in image matching. Accuracies related to location (in terms of latitude and longitude) and elevation of image features in the accumulation zone, ablation zone and nonglaciated regions with respect topographical map were checked. Based on geographical location and elevation of the snout derived from a topographical map of 1962 and the DEM and orthoimage of 1997, the two glaciers have been observed to have a retreat of about 690 m and 925 m, respectively. [ABSTRACT FROM AUTHOR]

Glacier ice thickness estimation can provide vital information for the estimation of glacier-stored freshwater resources and numerous field-based techniques have been used for this. Determination of ice thickness is a challenging task in mountain glaciers like in the Himalayas, due to harsh climate and rugged terrain conditions. In the present study, Ground Penetrating Radar (GPR) survey was carried out to estimate the ice thickness at Chhota Shigri glacier in Himachal Pradesh, India. This GPR carries a multiple low frequency antenna. GPR surveying was done in discrete mode at 16 MHz frequency with 4 m antenna gap (transmitter and receiver) at 50 cm data-acquisition intervals along the glacier length at bare ice of the ablation zone. The bedrock reflection was distinctly observed in the profiles indicating ice thickness varying from 110 to 150 m with approximately 0.049 KM3 water equivalent for the surveyed area. The results also showed subsurface features like point reflector and a linear non-bed reflection within the ablation ice zone. Total volume of ice and water equivalent of Chhota Shigri glacier was found to be 1.20 and 1.05 KM3 respectively, using area-depth relationship for the Himalayan glaciers. [ABSTRACT FROM AUTHOR]