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1
Shrestha, Jagat Kumar. "Impact of Road Cuts in Slope Stability in Hilly Regions of Nepal". Journal of Advanced College of Engineering and Management 6 (6 luglio 2021): 43–55. http://dx.doi.org/10.3126/jacem.v6i0.38289.
Testo completoAbstract (sommario):
This paper reviews the geological and engineering aspects of rural road construction in the hilly areas of Nepal. The general background in geological, climatic and geographical setting is briefly presented in reference to the five-zone Himalayan model for the Nepal Himalayas. Then, alignment selection of rural roads is discussed in the context of the five zone mountain model. The impact of road cross section design and construction on mountain slopes has been studied. The cut width is a key geometric design parameter that has a significant impact on slope stability and volume of excavation. The choice of cut width in cross-section is reviewed and appropriate cut width in cross-section is recommended in terrain slopes to minimize slope failures and volume of excavation.
2
Singh, H. P. "Cenozoic plant fossils and the Himalayan orogeny". Journal of Palaeosciences 40 (31 dicembre 1991): 328–35. http://dx.doi.org/10.54991/jop.1991.1782.
Testo completoAbstract (sommario):
Selected palyno- and megafloras from the Cenozoic Era of extrapeninsular India have been examined in the orogenic context of the Himalaya. Distribution of vegetations and variation in climates are in conformity with the periodic phases of the Himalayan uplift. Continued rise of the Himalaya acted as a barrier for the flow of moisture resulting in lesser precipitation, higher snow cover and increased aridity. In response to the topographical and climatic variations a progressive change occurred in the composition of vegetations during the past 60 Ma. The ancestral tropical floras inhabited the lower slopes, whereas the temperate floras colonized the higher slopes. Altitudinal segregation of floras is clearly evident from the Mid-Miocene orogeny. Palaeocene to Mid-Pleistocene plant diversity generally varies from evergreen, semi-evergreen, dry/moist deciduous, warm temperate to temperate forest types. Migrations/immigrations and extinctions of plant taxa were largely influenced by physiographical and climatic changes. Enrichment and diversification of the Neogene Himalayan floras have also been brought in through the process of evolution. Cult-historical evidences point out that the Himalayan range continued to rise even after the advent of man.
3
Singh, Pratap, K. S. Ramasastri e Naresh Kumar. "Topographical Influence on Precipitation Distribution in Different Ranges of Western Himalayas". Hydrology Research 26, n. 4-5 (1 agosto 1995): 259–84. http://dx.doi.org/10.2166/nh.1995.0015.
Testo completoAbstract (sommario):
Seasonal and annual distribution of rainfall and snowfall with elevation has been studied for outer, middle and greater Himalayan ranges of Chenab basin in the western Himalayas. Rainfall and snowfall exhibited different trends with elevation on the windward and leeward slopes of the three ranges of Himalayas. Seasonal characteristics of rainfall have shown a spill over effect on leeward side during winter, pre-monsoon, and post-monsoon seasons in the outer Himalayas. The role of orography in the middle Himalayas was found to be more pronounced for both rainfall and snowfall in comparison to other ranges of Himalayas. Variation of snowfall with elevation was more prominent in comparison to variation of rainfall. In the greater Himalayan range it is found that rainfall descreases exponentially with elevation and snowfall increases linearly. Rainfall becomes negligible at elevations beyond 4,000 m on the windward side of the greater Himalayan range. Efforts have also been made to explain whether variation in precipitation is due to changes in precipitation intensity or number of precipitation days or a combination of both.
4
Paliwal, Mahesh, Himkar Goswami, Arunava Ray, Ashutosh Kumar Bharati, Rajesh Rai e Manoj Khandelwal. "Stability Prediction of Residual Soil and Rock Slope Using Artificial Neural Network". Advances in Civil Engineering 2022 (30 aprile 2022): 1–14. http://dx.doi.org/10.1155/2022/4121193.
Testo completoAbstract (sommario):
A sudden downward movement of the geomaterial, either composed of soil, rock, or a mixture of both, along the mountain slopes due to various natural or anthropogenic factors is known as a landslide. The Himalayan Mountain slopes are either made up of residual soil or rocks. Residual soil is formed from weathering of the bedrock and mainly occurs in gentle-to-moderate slope inclinations. In contrast, steep slopes are mostly devoid of soil cover and are primarily rocky. A stability prediction system that can analyse the slope under both the condition of the soil or rock surface is missing. In this study, artificial neural network technology has been utilised to predict the stability of jointed rock and residual soil slope of the Himalayan region. The database for the artificial neural network was obtained from numerical simulation of several residual soils and rock slope models. Nonlinear equations have been formulated by coding the artificial neural network algorithm. An android application has also been developed to predict the stability of residual soil and rock slope instantly. It was observed that the developed android app provides promising results in predicting the factor of safety and stability state of the slopes.
5
Kundu, Jagadish, Kripamoy Sarkar, Ebrahim Ghaderpour, Gabriele Scarascia Mugnozza e Paolo Mazzanti. "A GIS-Based Kinematic Analysis for Jointed Rock Slope Stability: An Application to Himalayan Slopes". Land 12, n. 2 (2 febbraio 2023): 402. http://dx.doi.org/10.3390/land12020402.
Testo completoAbstract (sommario):
GIS-based kinematic stability analysis in rock slopes is a rare practice in geological engineering despite its immense potential to delineate unstable zones in a mountainous region. In this article, we have used a GIS-based modified technique to assess the efficiency of kinematic analysis in predicting shallow landslides in the rock slopes of the Himalayan mountains on a regional scale. The limited use of this technique is primarily due to the complexities involved in its practical application. To make this technique more effective and convenient usability, we present modified methods and a new application, ‘GISMR’, that works with the aid of GIS software for the determination of kinematic susceptibility. A modified kinematic analysis method was implemented to define the stability in terms of failure susceptibility on a scale of 0 to 100 rather than a conservative result, such as failure or non-failure. We also present another functionality of the GISMR that provides optimised slope angles over a region. This functionality could aid the decision-making process when selecting a suitable location for a road path or other engineering constructions that are impacted by unstable mountain slopes. The applicability of this new method was demonstrated in a rock failure-prone region in the mountains of the Indian Himalayas. The outcomes delineate the unstable slopes in the region, which are intersected by a strategic National Highway 05 and have a long history of landslide-related hazards. It was found that 9.61% of the area is susceptible to failure. However, 2.28% is classified as a low susceptible region, and 2.58% of the area is very-low susceptible. The regions with moderately high, high, and very-high susceptibility cover 2.78%, 1.49%, and 0.46% of the whole area, respectively. The results were evaluated by receiver operating characteristic curve and a frequency ratio method to represent the association between kinematic susceptibility and the mass movement inventory in the area. It is concluded that kinematic susceptibility has a strong relationship with landslide activity in the rock slopes of the Himalayan region.
6
Chaudhary, Vipin, R. S. Tripathi, Surjeet Singh e M. S. Raghuvanshi. "Distribution and population of Himalayan Marmot Marmota himalayana (Hodgson, 1841) (Mammalia: Rodentia: Sciuridae) in Leh-Ladakh, Jammu & Kashmir, India". Journal of Threatened Taxa 9, n. 11 (26 novembre 2017): 10886. http://dx.doi.org/10.11609/jott.3336.9.11.10886-10891.
Testo completoAbstract (sommario):
The Himalayan Marmot Marmota himalayana is one of the largest rodents of cold desert habitats, found mainly between 3,500–5,200 m above the timberline. It is regarded as an ecosystem engineer and constitutes part of the diet of some globally endangered carnivores in the Trans-Himalayan region. Being one of the least studied rodents, a survey was carried out in different habitats of Leh District along the altitude gradient to assess the status and distribution of Himalayan Marmots. A total of 110 individuals of Himalayan Marmots were sighted in the surveyed stretches of Leh District with a maximum mean count of encounter of 2.71 in the Tangtse-Chushul sector. The grasslands were the most preferred habitat (41.67% activity observed), whereas, cultivation area being frequently disturbed for agricultural operation were least preferred by the marmot. Most of the population of marmot was found between 4,000–4,500 m altitude and the steep slopes (42.05%) where loose soil was available for excavation of burrows.
7
Thayyen, R. J., e A. P. Dimri. "Factors controlling Slope Environmental Lapse Rate (SELR) of temperature in the monsoon and cold-arid glacio-hydrological regimes of the Himalaya". Cryosphere Discussions 8, n. 6 (6 novembre 2014): 5645–86. http://dx.doi.org/10.5194/tcd-8-5645-2014.
Testo completoAbstract (sommario):
Abstract. Moisture, temperature and precipitation interplay forced through the orographic processes sustains the Himalayan cryospheric system. However, factors controlling the Slope Environmental Lapse Rate (SELR) of temperature along the higher Himalayan mountain slopes across various glacio-hydrologic regimes remain as a key knowledge gap. Present study dwells on the orographic processes driving the moisture–temperature interplay in the monsoon and cold-arid glacio-hydrological regimes of the Himalaya. Systematic data collection at three altitudes between 2540 and 3763 m a.s.l. in the Garhwal Himalaya (hereafter called monsoon regime) and between 3500 and 5600 m a.s.l. in the Ladakh Himalaya (herefater called cold-arid regime) revealed moistrue control on temperature distribution at temporal and spatial scales. Observed daily SELR of temperature ranges between 9.0 to 1.9 °C km−1 and 17.0 to 2.8 °C km−1 in the monsoon and cold-arid regimes respectively highlighting strong regional variability. Moisture influx to the region, either from Indian summer monsoon (ISM) or from Indian winter monsoon (IWM) forced lowering of SELR. This phenophena of "monsoon lowering" of SELR is due to the release latent heat of condensation from orographically focred lifted air parcel. Seasonal response of SELR in the monsoon regime is found to be closly linked with the variations in the local lifting condensation levels (LCL). Contrary to this, cold-arid system is characterised by the extremely high values of daily SELR upto 17 °C km−1 signifying the extremely arid conditions prevailing in summer. Distinctly lower SELR devoid of monsoon lowering at higher altitude sections of monsoon and cold-arid regimes suggests sustained wetter high altitude regimes. We have proposed a SELR model for both glacio-hydrological regimes demostrating with two sections each using a derivative of the Clausius–Clapeyron relationship by deriving monthly SELR indices. It has been proposed that the manifestations of presence or absence of moisture is the single most important factor determining the temperature distribution along the higher Himalayan slopes driven by the orographic forcings. This work also suggests that the arbitary use of temperature lapse rate to extrapolate temperature to the higher Himalaya is extremely untenable.
8
Zgorzelski, Marek. "Ladakh and Zanskar". Miscellanea Geographica 12, n. 1 (1 dicembre 2006): 13–24. http://dx.doi.org/10.2478/mgrsd-2006-0002.
Testo completoAbstract (sommario):
Abstract The Himalayan mountain chain is orographically fragmented, both in the east-west and in the north-south directions. The latter area is characterised by a greater landscape diversity, owing to its zonality and the vertical zonation of both climate and vegetation. In terms of tectonics and orography, and taking into account the prevalent influence of the monsoon and continental climates, the Himalayan mountain system can be divided into two parts – the external arc (southern), that is the Higher (or Great) Himalayas and the internal arc (northern), that is the so-called Trans-Himalayas. Similarly to the external arc of the Himalayas, the post-glacial relief in the Trans-Himalayas is marginal only. It is an area with a prevalence of denudation (nival, frost, gravitation and eolian) processes. Slopes of tectonic valleys or basins, covered with colourful surface deposits rising as high as even two thirds of their altitude, dominate the landscape. The Zanskar ridges and the Ladakh range represent a transitional zone between the Trans-himalayas and Eastern Karakoram.
9
Farooq, Imran, G. M. Bhat, S. K. Pandita, Rameshwar Sangra, Arjun Singh, Gulzar Hussain, Yudhbir Singh e Ahsan-ul-Haq. "Study of slope instability on the Bhaderwah–Bani Highway, Jammu and Kashmir, India". Journal of Palaeosciences 68, n. (1-2) (31 dicembre 2019): 163–72. http://dx.doi.org/10.54991/jop.2019.42.
Testo completoAbstract (sommario):
Northwest Himalaya has witnessed lot of mass movements during the Quaternary period which have led to palaeoenvironmental degradation and deposition of erratic size sediments. These sediments have developed as fossil slides along the mountain slopes. In last few decades, the frequency of landslides has increased due to various factors such as complex geology, geotechnical properties of the rocks and anthropogenic activities. The investigation of rock slopes require geo–engineering evaluation to assess the instability of critical slopes leading to landslides particularly in the Himalayan region, where rocks are highly folded, faulted, jointed and weathered. In the present study, a total of 15 rock slopes have been selected for rapid assessment of instability condition using rock mass rating basic (RMRb), slope mass rating (SMR) and kinematics analysis techniques along Bhaderwah–Bani Highway in Jammu and Kashmir. Field surveys were conducted regarding required input data collection followed by laboratory works. The results of RMRb show two classes of rock mass, i.e., Class II–Good (86.58%) and Class III–Fair (13.42%). The SMR index classify rock slopes into different stability class results, which infers completely unstable (L4 and L14), unstable (L1, L2, L3, L8, L9, L11, L12 and L13), partially stable (L5, L6 and L7) and stable (L10 and L15) categories. The final output of kinematic analysis verify different modes of structurally controlled slope failures i.e., planar (30.72%), wedge (57.6%) and toppling (11.52%), representing all 15 sites in the study area.
10
Thapa, Prem Bahadur, Bikash Phuyal e Krishna Kumar Shrestha. "Spatial variability of slope movements in central and western Nepal Himalaya: Evaluating large-scale landslides to cut-slopes". Journal of Nepal Geological Society 65 (22 agosto 2023): 183–94. http://dx.doi.org/10.3126/jngs.v65i01.57777.
Testo completoAbstract (sommario):
Spatial variability of slope movements is common in the Himalayan terrain of central and western Nepal Himalaya due to the intricate topography, differential geo-environment, and frequent rainstorms. The process of mass movements in the Himalaya has been described in the past by many researchers. The spatial variability of slope movement phenomena is scale dependent and is affected by causative and triggering processes. The limited researchers delivered output to understand the scale-dependent spatial variability resulting from the causative and triggering mechanism of slope movement phenomena. This study has presented a rigorous scientific examination of the spatial variability of slope movements, focusing on large-scale landslides to cut slopes across the central and western regions of the Nepal Himalaya. To achieve this, a multidisciplinary approach was employed, encompassing geospatial analysis, remote sensing, and field investigations. High-resolution satellite imagery was utilized to identify and map slope movement features, while digital terrain analysis techniques aided in quantifying their characteristics. This approach quantitatively analyzed slope movement distribution, frequency, and characteristics in terms of various geo-environmental settings. The findings reveal diverse patterns of slope movements influenced by complex interactions between geological factors, geomorphology, triggering factors, and anthropogenic activities. Geological and geomorphological heterogeneity play roles differently in the spatial distribution of slope movements. Moreover, rainfall distribution and peak ground acceleration act similarly for the scale dependency phenomena of slope movement. The spatial variation concerning the causative and triggering variables signify the scale-dependency nature of slope movement processes. This study has provided insights into the scale dependency and spatially variable nature of slope movement events due to variations in causative and triggering mechanisms in the Nepal Himalaya.
11
Negi, H. S., e A. Kokhanovsky. "Retrieval of snow grain size and albedo of Western Himalayan snow cover using satellite data". Cryosphere Discussions 5, n. 1 (16 febbraio 2011): 605–53. http://dx.doi.org/10.5194/tcd-5-605-2011.
Testo completoAbstract (sommario):
Abstract. In the present study we describe the retrievals of snow grain size and spectral albedo (plane and spherical albedo) for Western Himalayan snow cover using Hyperion sensor data. The asymptotic radiative transfer (ART) theory was explored for the snow retrievals. To make the methodology operational only five spectral bands (440, 500, 1050, 1240 and 1650 nm) of Hyperion were used for snow parameters retrieval. The bi-spectral method (440 nm in the visible and 1050/1240 nm in the NIR region) was used to retrieve snow grain size. Spectral albedos were retrieved using satellite reflectances and estimated grain size. A good agreement was observed between retrieved snow parameters and ground observed snow-meteorological conditions. The satellite retrieved grain sizes were compared with field spectroradiometer retrieved grain sizes and close results were found for Lower Himalayan snow. The wavelength 1240 nm was found to be more suitable compared to 1050 nm for grain size retrieval along the steep slopes. The methodology was able to retrieve the spatial variations in snow parameters in different parts of Western Himalaya which are due to snow climatic and terrain conditions of Himalaya. This methodology is of importance for operational snow cover and glacier monitoring in Himalayan region using space-borne and air-borne sensors.
12
Negi, H. S., e A. Kokhanovsky. "Retrieval of snow grain size and albedo of western Himalayan snow cover using satellite data". Cryosphere 5, n. 4 (14 ottobre 2011): 831–47. http://dx.doi.org/10.5194/tc-5-831-2011.
Testo completoAbstract (sommario):
Abstract. In the present study we describe the retrievals of snow grain size and spectral albedo (plane and spherical albedo) for western Himalayan snow cover using Hyperion sensor data. The asymptotic radiative transfer (ART) theory was explored for the snow retrievals. To make the methodology operational only five spectral bands (440, 500, 1050, 1240 and 1650 nm) of Hyperion were used for snow parameters retrieval. The bi-spectral method (440 nm in the visible and 1050/1240 nm in the NIR region) was used to retrieve snow grain size. Spectral albedos were retrieved using satellite reflectances and estimated grain size. A good agreement was observed between retrieved snow parameters and ground observed snow-meteorological conditions. The satellite retrieved grain sizes were compared with field spectroradiometer retrieved grain sizes and close results were found for lower Himalayan snow. The wavelength 1240 nm was found to be more suitable compared to 1050 nm for grain size retrieval along the steep slopes. The methodology was able to retrieve the spatial variations in snow parameters in different parts of western Himalaya which are due to snow climatic and terrain conditions of Himalaya. This methodology is of importance for operational snow cover and glacier monitoring in Himalayan region using space-borne and air-borne sensors.
13
P.C, Shakti, Dhiraj Pradhananga, Wenchao Ma e Pei Wang. "An Overview of Glaciers Distribution in the Nepal Himalaya". Hydro Nepal: Journal of Water, Energy and Environment 13 (12 marzo 2014): 20–27. http://dx.doi.org/10.3126/hn.v13i0.10034.
Testo completoAbstract (sommario):
Correction: On 7th September 2015, Pei Wang was included as an author on this paper. He was omitted from the paper by mistake. John W. Pomeroy was removed as an author of the paper but was included in the Acknowledgements of the paper (p.26)Abstract:Glaciers in the Himalayas are the important resource for fresh water. Continuous releases of the water from these glaciers make an important contribution to the drinking water, agriculture, and hydropower supply of densely populated regions in south and central Asia. Glaciers are not only a necessity for the survival of the people living in the low lying areas but also for their prosperity. Therefore, special attention should be given to detail research in the distribution of the glaciers in the Himalayan region and its surroundings. Physical parameters of glaciers area, length, depth, elevation profiles were analyzed based on the data provided by WGMS and NSIDC (1989), which was updated in 2012. Machhapuchhre, Thyangbo, Cho Oyu, Taweche, Setta, Tingbo and Kanchanjanga glaciers were found as the smallest glaciers in terms of area (<1km2), mean length (< 2km) and mean depth (40m) in the Nepal Himalaya. Langtang Ngojumba, Barun and Yalung glaciers were found as the largest glaciers in terms of area (>50km2). Large difference between start and end elevation point of glaciers of Khumbu, Ngojumba, Imja, Langtang indicates coverage area profiles are large and located in steep slopes of the Nepal Himalaya, which may result in linear erosions and avalanches. This paper also discusses about the Glacier Lake Outburst Flood (GLOF) in the Himalayan region.HYDRO NEPAL Journal of Water, Energy and EnvironmentIssue No. 13, July 2013Page:20-27 Uploaded date: 3/12/2014
14
Lesser, Lawrence M. "Mathematical Lens: Slippery Slopes". Mathematics Teacher 102, n. 2 (settembre 2008): 116–19. http://dx.doi.org/10.5951/mt.102.2.0116.
Testo completoAbstract (sommario):
The University of Texas at El Paso's many distinctions include being the nation's only doctoral-research-intensive university with a majority Mexican-American student population and having the first NCAA basketball team start an all-black lineup in the championship game (in 1966). Also, UTEP is unique in the Western Hemisphere for its reproduction of Bhutanese architecture. The inspiration for this distinctive feature dates back almost a century, when a UTEP dean's spouse saw photographs of Bhutan's buildings and landscapes in National Geographic (see, e.g., the January 1910 and the April 1914 issues). She was struck by the similarities between the mountain vistas of that eastern Himalayan kingdom and those of the El Paso region.
15
Lesser, Lawrence M. "Mathematical Lens: Slippery Slopes". Mathematics Teacher 102, n. 2 (settembre 2008): 116–19. http://dx.doi.org/10.5951/mt.102.2.0116.
Testo completoAbstract (sommario):
The University of Texas at El Paso's many distinctions include being the nation's only doctoral-research-intensive university with a majority Mexican-American student population and having the first NCAA basketball team start an all-black lineup in the championship game (in 1966). Also, UTEP is unique in the Western Hemisphere for its reproduction of Bhutanese architecture. The inspiration for this distinctive feature dates back almost a century, when a UTEP dean's spouse saw photographs of Bhutan's buildings and landscapes in National Geographic (see, e.g., the January 1910 and the April 1914 issues). She was struck by the similarities between the mountain vistas of that eastern Himalayan kingdom and those of the El Paso region.
16
Pandey, Vinay Kumar. "Hill Slope Failure During The Development Of Infrastructure Projects In Himalaya: Case Study of Udhampur- Ramban National Highway, Jammu and Kashmir, India". South Florida Journal of Development 2, n. 5 (26 novembre 2021): 7679–99. http://dx.doi.org/10.46932/sfjdv2n5-101.
Testo completoAbstract (sommario):
Himalaya is youngest tectonic Active Mountain and northern boundary of India. Various infrastructure projects are under develop in Himalayan region for the better connectivity of peoples and national security of border line. Widening of 295 km National Highway-44 in Jammu and Kashmir is an important developmental project. The highway passes through Outer Himalayan and Higher Himalayan sequences of rocks and is frequently affected by landslides at various places. The paper deals with 43 km Udhampur-Chenani and Nashri- Ramban section of the highway within sedimentary and metamorphic rock sequence. The area is prone to landslides on account of fragile geological, topographic and hydrological conditions. The study area has high rainfall intensity and numerous old landslides zones. During the project feasibility stage, project authority has identified the landslide prone area and suggested precautionary measures but during the construction work various unpredicted landslide and ground sinking events happened which given trouble in project construction cost and project completion time. In this paper, the challenges faced due to landslide and ground failure as failure of old slide adjutant to road construction, agriculture and residential ground failure at higher altitude due to road construction, collapse of high tension towers in cut slopes; its impact on construction activities; are discussed with mitigation measures for unidentified landslide related challenges.
17
Shrestha, Dibas, e Rashila Deshar. "Spatial Variations in the Diurnal Pattern of Precipitation over Nepal Himalayas". Nepal Journal of Science and Technology 15, n. 2 (15 febbraio 2015): 57–64. http://dx.doi.org/10.3126/njst.v15i2.12116.
Testo completoAbstract (sommario):
The Central Himalayan Region (Nepal Himalayas), comprised of two clear sub-parallel mountain ranges, is atypical location for studying the impact of rugged topography on spatio temporal variations of precipitation. The relationship between topography and diurnal cycles of rainfall have been investigated utilizing 13-year (1998–2010) high resolution (0.05° × 0.05°) Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data. An investigation of diurnal cycle of precipitation revealed an afternoon maximum during the pre-monsoon season (March–May) and midnight–early morning maximum during the summer monsoon season (June–August)over the southern slopes of the Himalayas. The summer monsoon exhibited a robust spatial variation of diurnal cycle of precipitation, during afternoon-evening time, primary rainfall peak appeared along the Lesser Himalayas (~2,000–2,200 m above mean sea level), while early-morning rain in contrast showed maximum concentration along the southern margin of the Himalayas (~500–700 m above MSL). An afternoon-evening rainfall peak was attributed to higher rain frequency, whereas early-morning rainfall peak was attributed to fewer but rather intense rainfall. It is suggested that, confluence between down slope and moist south easterly monsoon flow triggers convection near the foothills of the Himalayas during early morning period. The results further suggested the morning precipitation moves southward in the mature monsoon season.DOI: http://dx.doi.org/njst.v15i2.12116Nepal Journal of Science and Technology Vol. 15, No.2 (2014), 57-64
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Bhardwaj, D. R., Habibullah Tahiry, Prashant Sharma, Nazir A. Pala, Dhirender Kumar, Amit Kumar e Bharti Bharti. "Influence of Aspect and Elevational Gradient on Vegetation Pattern, Tree Characteristics and Ecosystem Carbon Density in Northwestern Himalayas". Land 10, n. 11 (20 ottobre 2021): 1109. http://dx.doi.org/10.3390/land10111109.
Testo completoAbstract (sommario):
Himalayan forest has been threatened by rapid anthropogenic activities, resulting in the loss of forest diversity and climate change. The present study was carried out on four aspects (northern, southern, western and eastern), at three different altitudinal ranges, namely, 1000–1300 m above sea level (m a.s.l.), 1300–1600 m a.s.l. and 1600–1900 m a.s.l., and at three diverse mountain ranges (Kalaghat, Barog and Nangali) of sub-temperate forest ecosystems of the mid Himalayan ranges, to elucidate their influence on vegetation, tree characteristics and ecosystem carbon density. The results revealed that Pinus roxburghii is the most dominant forest community of the mid Himalaya’s forest, irrespective of altitudinal gradient and slope. The south-facing slopes are occupied by the xerophytic tree species frequently found in the lower Shiwalik P. roxburghii forest, whereas the north-facing ones are dominated by mesophyllic species, such as Cedrus deodara and Quercus leucotrichophora, which commonly grows in the northwestern Himalayan temperate forest ecosystem. The maximum stem density (211.00 Nha−1) was found at 1000–1300 m a.s.l., and on the northern aspect (211.00 Nha−1). The maximum stem volume (236.50 m3 ha−1) was observed on the northern aspect at 1000–1300 m a.s.l., whereas the minimum (32.167 m3 ha−1) in the southern aspect at 1300–1600 m a.s.l. The maximum carbon density (149.90 Mg ha−1) was found on the northern aspect and declined with increasing elevation from 123.20 to 74.78 Mg ha−1. Overall, the study establishes that the southern and western aspects are very low in carbon density, whereas the northern aspect represents higher biodiversity as well as carbon and nutrient stocks. Therefore, aspect and altitude should be given due importance for efficient managing of biodiversity and mitigating climate change.
19
Fort, Monique, Douglas W. Burbank e Pierre Freytet. "Lacustrine Sedimentation in a Semiarid Alpine Setting: An Example from Ladakh, Northwestern Himalaya". Quaternary Research 31, n. 3 (maggio 1989): 332–50. http://dx.doi.org/10.1016/0033-5894(89)90041-0.
Testo completoAbstract (sommario):
AbstractThe Lamayuru lacustrine strata in Ladakh typify many of the carbonate-rich Pleistocene alpine lakes found in the semiarid environment of the northern Himalaya. Created by a 200-m-thick landslide, the lake was in existence by at least 35,000 yr ago, and may have persisted until 500–1000 yr ago. Represented in the center by thin turbidites and laminated muds, the lacustrine sedimentation along the lake margins and low-relief deltas characteristically displays a marked contrast between (1) clastic lenses representing rapid, sporadic, matrix-poor debris flows and periglacial inputs from the alpine slopes and (2) abundant, diverse, shallow-water, biologically dominated carbonate strata, among which organism-rich, chalky beds and oncolithic and encrusted stem-rich strata predominate. Resemblances of the Lamayuru lacustrine strata and their setting to those of former lakes throughout areas north of the Greater Himalayan crest suggest that the alpine, semi-arid environment would favor diversified, spacially restricted carbonate sedimentation punctuated by occasional clastic influxes. Such a depositional regime contrasts strongly with that found immediately south of the Himalayan crest where more humid conditions promote a more continuous clastic influx into intramontane lakes.
20
Mampuku, M., T. Yamanaka, M. Uchida, R. Fujii, T. Maki e H. Sakai. "Changes in C<sub>3</sub>/C<sub>4</sub> vegetation in the continental interior of the Central Himalayas associated with monsoonal paleoclimatic changes during the last 600 kyr". Climate of the Past 4, n. 1 (2 gennaio 2008): 1–9. http://dx.doi.org/10.5194/cp-4-1-2008.
Testo completoAbstract (sommario):
Abstract. A continuous lacustrine sediment core obtained from the Kathmandu Valley in the Central Himalayas revealed that cyclical changes in C3/C4 vegetation corresponded to global glacial-interglacial cycles from marine isotope stages (MIS) 15 to MIS 4. The C3/C4 vegetation shifts were reconstructed from significant changes in the δ13C values of bulk organic carbon. Glacial ages were characterized by significant 13C enrichment, due to the expansion of C4 plants, attributed to an intensification of aridity. Thus, the southwest (SW) summer monsoon, which brings the majority of rainfall to the Central Himalayan southern slopes, would have been weaker. Marine sediment cores from the Indian Ocean and Arabian Sea have demonstrated a weaker SW monsoon during glacial periods, and our results confirm that arid conditions and a weak SW monsoon prevailed in the continental interior of the Central Himalayas during glacial ages. This study provides the first continuous record for the continental interior of paleoenvironmental changes directly influenced by the Indian monsoon.
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Mampuku, M., T. Yamanaka, M. Uchida, R. Fujii, T. Maki e H. Sakai. "Changes in C<sub>3</sub>/C<sub>4</sub> vegetation in the continental interior of the Central Himalayas associated with monsoonal paleoclimatic changes during the last 600 kyr". Climate of the Past Discussions 3, n. 4 (6 luglio 2007): 871–98. http://dx.doi.org/10.5194/cpd-3-871-2007.
Testo completoAbstract (sommario):
Abstract. A continuous lacustrine sediment core obtained from the Kathmandu Valley in the Central Himalayas revealed that cyclical changes in C3/C4 vegetation corresponded to global glacial-interglacial cycles from marine isotope stages (MIS) 15 to MIS 4. The C3/C4 vegetation shifts were reconstructed from significant changes in the δ13C values of bulk organic carbon. Glacial ages were characterized by significant 13C enrichment, due to the expansion of C4 plants, attributed to an intensification of aridity. Thus, the southwest (SW) summer monsoon, which brings the majority of rainfall to the Central Himalayan southern slopes, would have been weaker. Marine sediment cores from the Indian Ocean and Arabian Sea have demonstrated a weaker SW monsoon during glacial periods, and our results confirm that arid conditions and a weak SW monsoon prevailed in the continental interior of the Central Himalayas during glacial ages. This study provides the first continuous record for the continental interior of paleoenvironmental changes directly influenced by the Indian monsoon.
22
Kichloo, Muzaffar A., Asha Sohil e Neeraj Sharma. "Wildlife at the crossroads: wild animal road kills due to vehicular collision on a mountainous highway in northwestern Himalayan region". Journal of Threatened Taxa 14, n. 1 (26 gennaio 2022): 20517–22. http://dx.doi.org/10.11609/jott.7713.14.1.20517-20522.
Testo completoAbstract (sommario):
Wildlife mortality due to vehicular collision is well known across the world and the number of such incidences is steadily rising in Himalaya as well. To assess the quantum of wildlife road kills, we conducted an intensive survey spanning 33 months along a mountainous National Highway 244 in the Union Territory of Jammu & Kashmir. Forty-nine wild animal carcasses of 13 species of higher vertebrates were observed lying on the road, shoulders, edges, and valley slopes. These included seven mammals, four birds, and two reptiles. This survey, first of its kind in this part of the Himalaya would be helpful in understanding the underlying reasons of the rising wildlife fatalities on the hill roads, identifying susceptible hotspots, and developing measures to address this new threat to Himalayan wildlife. We recommend creating wildlife passages, raising speed halters, and placing warning signages in vulnerable sections to reduce the road-related wildlife mortality in such mountainous highways.
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Awasthi, N. "Changing patterns of vegetation through Siwalik succession". Journal of Palaeosciences 40 (31 dicembre 1991): 312–27. http://dx.doi.org/10.54991/jop.1991.1781.
Testo completoAbstract (sommario):
The palaeobotanical record from the Neogene of Himalaya has been examined and an attempt has been made to reconstruct the vegetation patterns and throw light on palaeoclimate of the region during Siwalik time. Though the flora of the Pre-Siwalik Neogene from which the Siwalik flora evolved is poorly documented, a few palynofossils from the Kasauli and Dagshai formations indicate the existence of subtropical to temperate vegetation in the Upper reaches of the newly built Himalaya. On the contrary, a fairly rich assemblage of megafossils from the Siwalik indicates widespread tropical evergreen to moist deciduous mixed forest in the lowland sub-Himalayan zone during Middle Miocene-Pliocene The assemblage is dominated by wet evergreen dipterocarps and associated taxa, most of which are known to have entered the Indian subcontinent from southeast Asia during Miocene and subsequently spread all over and finally reached the lower slopes of sub-Himalaya. This has resulted increase in the diversity of tropical vegetation.
The post-Pliocene orogeny of Himalaya brought great changes in the topography and climate which adversely affected the vegetation patterns of the region. The Early and Middle Siwalik tropical evergreen forest whose chief component are Anisoptera, Dipterocarpus, Hopea, Shorea (other than Shorea robusta), Polyalthia, Calophyllum, Aphanamixis, Dysoxylum, Gluta, Dracontomelum, Mangifera, Swintonia, Cynometra, Koompassia, Ormosia, Pongamia, Sindora, Duabanga, Diospyros spp., Myristica, etc. started dwindling towards the end of Middle Siwalik and subsequently disappeared from western and central sectors, though a few taxa like Mangifera, Litsea, Cinnamomum, Bauhinia, Dalbergia, Ficus, etc. continued to adjust to the new climatic conditions. Extinction of tropical evergreen taxa and further rise of Himalaya gave way to proliferation and diversification of tropical and subtropical moist deciduous to dry deciduous temperate vegetation in the lower and higher slopes respectively, as is also evidenced from the palynological record.
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Siddique, Tariq, S. P. Pradhan, Vikram Vishal e T. N. Singh. "Applicability of Q-slope Method in the Himalayan Road Cut Rock Slopes and Its Comparison with CSMR". Rock Mechanics and Rock Engineering 53, n. 10 (24 giugno 2020): 4509–22. http://dx.doi.org/10.1007/s00603-020-02176-2.
Testo completo
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Limbu, Dil Kumar, e Zhan-Huan Shang. "Estimating the population density of the Himalayan Rangeland weed Swertia ciliata (G. Don) Burtt.: An impact of topography and disturbance". Nepalese Journal of Biosciences 7, n. 1 (1 giugno 2017): 26–34. http://dx.doi.org/10.3126/njbs.v7i1.41756.
Testo completoAbstract (sommario):
Swertia ciliata (G. Don) Burtt. is one of the most problematic weeds in the Himalayan rangelands. The main objective of this work is to assess the magnitude of S. ciliata invasion and analyze the impact of topographic factors and the disturbances on the distribution and population density. The work was conducted during August and September 2012 in the Tinjure-Milke mountain ridge at Gupha Pokhari, Nepal. The rangeland aspects (east, south and west) were considered the first level factor; and slopes (≤45 degree and ≥45 degree inclination) and the disturbance intensity were the second and third factors, respectively. Line transects made up 4 m2, 74 quadrats were laid down randomly to enumerate the weed population. The average population density of the S. ciliata was 127 plants m-2. The population density was found significantly different by the effects of the disturbances as well as aspects whereas the effect of the two slopes was found insignificant to the population density. A space is left for further research by ecological and edaphic factors. The study reveals that the infestation degree of S. ciliata is at a considerable level in the Himalayan rangeland and needs immediate control measures.
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Ballesteros-Cánovas, J. A., D. Trappmann, J. Madrigal-González, N. Eckert e M. Stoffel. "Climate warming enhances snow avalanche risk in the Western Himalayas". Proceedings of the National Academy of Sciences 115, n. 13 (13 marzo 2018): 3410–15. http://dx.doi.org/10.1073/pnas.1716913115.
Testo completoAbstract (sommario):
Ongoing climate warming has been demonstrated to impact the cryosphere in the Indian Himalayas, with substantial consequences for the risk of disasters, human well-being, and terrestrial ecosystems. Here, we present evidence that the warming observed in recent decades has been accompanied by increased snow avalanche frequency in the Western Indian Himalayas. Using dendrogeomorphic techniques, we reconstruct the longest time series (150 y) of the occurrence and runout distances of snow avalanches that is currently available for the Himalayas. We apply a generalized linear autoregressive moving average model to demonstrate linkages between climate warming and the observed increase in the incidence of snow avalanches. Warming air temperatures in winter and early spring have indeed favored the wetting of snow and the formation of wet snow avalanches, which are now able to reach down to subalpine slopes, where they have high potential to cause damage. These findings contradict the intuitive notion that warming results in less snow, and thus lower avalanche activity, and have major implications for the Western Himalayan region, an area where human pressure is constantly increasing. Specifically, increasing traffic on a steadily expanding road network is calling for an immediate design of risk mitigation strategies and disaster risk policies to enhance climate change adaption in the wider study region.
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Okopińska, Anna. "Himalaje Sikkimu własnością ludu Lepcza". Góry, Literatura, Kultura 14 (18 agosto 2021): 299–314. http://dx.doi.org/10.19195/2084-4107.14.21.
Testo completoAbstract (sommario):
Lepchas are an indigenous people inhabiting the foothills of the eastern Himalaya. Their myths and narratives provide evidence that they belong to this land, and had not migrated from any other region. Presently the Lepchas reside in remote Himalayan valleys, where they were gradually driven by successive waves of immigrants from Tibet, Nepal and West Bengal. Lepchas are intrinsically devoted to nature. The rivers, lakes, rocks, forests and all animals seem to be sacred to them. They worship the Himalayan peaks towering over their villages. Every clan has his own sacred mountain and lake. The most important goddess is the mighty eight-thousander peak of Kangchenjunga that is clearly visible from every Lepcha village. Lepchas believe that their ancestors were created from the snows of the Kangchenjunga. Now, they are living together with gods in the Mayel Lyang — the mythical paradise hidden somewhere on the slopes of the mountain, inaccessible for mortal beings. Over the generations, the Lepchas have accumulated an extraordinary amount of knowledge about the climate, meteorological phenomena, geography of the region, and agriculture on steep slopes. These people fulfil their needs with natural resources as well as the help of hard work, and have great care for nature. Lepchas know all the animals and wildly growing plants there, and their rich language has names for even the smallest of them. The most impressive is their adaptation to life in extremely difficult geographic and climatic conditions with the constant risk of earthquakes, floods and landslides caused by heavy rainfalls of the monsoon season. Their farms are small and modest, but well adapted to those threats. Family and clan ties are very strong. They help each other with houses construction, sickness care, and agricultural harvest. Lepchas do not care for material goods and despite extremely difficult conditions they are happy and content with their life. Their attitude towards life may be an inspiration for us, inhabitants of the “first world”, addicted to consumerism and materialistic values.
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Gautam, R., N. C. Hsu, S. C. Tsay, K. M. Lau, B. Holben, S. Bell, A. Smirnov et al. "Accumulation of aerosols over the Indo-Gangetic plains and southern slopes of the Himalayas: distribution, properties and radiative effects during the 2009 pre-monsoon season". Atmospheric Chemistry and Physics 11, n. 24 (20 dicembre 2011): 12841–63. http://dx.doi.org/10.5194/acp-11-12841-2011.
Testo completoAbstract (sommario):
Abstract. We examine the distribution of aerosols and associated optical/radiative properties in the Gangetic-Himalayan region from simultaneous radiometric measurements over the Indo-Gangetic Plains (IGP) and the foothill/southern slopes of the Himalayas during the 2009 pre-monsoon season. Enhanced dust transport extending from the Southwest Asian arid regions into the IGP, results in seasonal mean (April–June) aerosol optical depths of over 0.6 – highest over Southern Asia. The influence of dust loading is greater over the Western IGP as suggested by pronounced coarse mode peak in aerosol size distribution and spectral single scattering albedo (SSA). Transported dust in the IGP, driven by prevailing westerly airmass, is found to be more absorbing (SSA550 nm<0.9) than the near-desert region in Northwestern (NW) India suggesting mixing with carbonaceous aerosols in the IGP. On the contrary, significantly reduced dust transport is observed over eastern IGP and foothill/elevated Himalayan slopes in Nepal where strongly absorbing haze is prevalent, as indicated by lower SSA (0.85–0.9 at 440–1020 nm), suggesting presence of more absorbing aerosols compared to IGP. Additionally, our observations show a distinct diurnal pattern of aerosols with characteristic large afternoon peak, from foothill to elevated mountain locations, associated with increased upslope transport of pollutants – that likely represent large-scale lifting of absorbing aerosols along the elevated slopes during pre-monsoon season. In terms of radiative impact of aerosols, over the source region of NW India, diurnal mean reduction in solar radiation fluxes was estimated to be 19–23 Wm−2 at surface (12–15% of the surface solar insolation). Furthermore, based on limited observations of aerosol optical properties during the pre-monsoon period and comparison of our radiative forcing estimates with published literature, there exists a general spatial heterogeneity in the regional aerosol forcing, associated with the absorbing aerosol distribution over northern India, with both diurnal mean surface forcing and forcing efficiency over the IGP exceeding that over Northwestern India. Finally, the role of the seasonal progressive buildup of aerosol loading and water vapor is investigated in the observed net aerosol radiative effect over Northwestern India. The radiative impact of water vapor is found to amplify the net regional aerosol radiative forcing suggesting that the two exert forcing in tandem leading to enhanced surface cooling. It is suggested that water vapor contribution should be taken into account while assessing aerosol forcing impact for this region and other seasonally similar environments.
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Thakur, Neha, e Dr Sakshi Sharma. "Study of Sustainable Techniques for Effective Risk Management and Control: A Review". International Journal for Research in Applied Science and Engineering Technology 10, n. 6 (30 giugno 2022): 1688–96. http://dx.doi.org/10.22214/ijraset.2022.44121.
Testo completoAbstract (sommario):
Abstract: A geological disturbance is a broader term that refers to a variety of ground motions such as rock falls, slope failure, and shallow debris flows. The study of landslides has fetched a lot of interest recently, owing to a growing awareness of the socioeconomic consequences associated. The land in the mountainous region is especially susceptible to landslides due to its complicated geological context. Landslides are generally caused by the slope changing from a stable to an unstable condition, which can be caused by a variety of factors such as pore water pressure destabilising the slopes, loss or absence of vertical vegetative structure (after a wild fire or fire in forests lasting two or four days), erosion of toe of slopes by river, significant rain falls, earthquakes causing liquefaction of slope, blasting, earth work which alters the slope and imposes new load on it. If the slope is not stable and must support a large soil mass, the entire wedge may slide, resulting in the second type of landslide. Although climate change has also contributed to the occurrence of such disasters like landslides. As we all are aware about the relative causes of landslides, still it is a major concern for governmental organisations, authorities, geotechnical engineers and sub-urban planners for both public and structural safety. Landslides are a major issue in hilly areas especially in Himalayan region of India, where populace is more dependent on native resources and are prone to landslides too.
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Ghimire, Balkrishna, Kumar P. Mainali, Hari Datta Lekhak, Ram Prasad Chaudhary e Amal Kumar Ghimeray. "Regeneration of Pinus wallichiana AB Jackson in a trans-Himalayan dry valley of north-central Nepal". Himalayan Journal of Sciences 6, n. 8 (28 giugno 2011): 19–26. http://dx.doi.org/10.3126/hjs.v6i8.1798.
Testo completoAbstract (sommario):
We studied the elevational pattern of forest composition and regeneration of the subalpine conifer tree species Pinus wallichiana in Manang, a trans-Himalayan dry valley in north-central Nepal. Thirty-five quadrats (10 m × 10 m) were laid between 3300 and 4000 masl on both north- and south-facing slopes. We measured diameter at breast height (DBH) of each mature individual of all tree species (DBH ≥10 cm), and recorded the number of seedlings (DBH <10 cm, height <30 cm) and saplings (DBH <10 cm, height >30 cm). We also measured soil moisture and soil pH, estimated canopy cover, and recorded slope and altitude in each quadrat. For all species together and for several species individually, tree density, seedling density, sapling density and tree basal area were found to decrease with elevation on both north and south aspects. This trend is largely explained by the progressively harsher environment at higher elevations. The north-facing slopes in our study area have denser forests than the south-facing slopes, the density of all size classes (seedling, sapling and mature plants) and basal area being greater on the northern aspects. These aspect-wide differences are attributable to the stark difference in soil moisture between northern and southern aspects, which is in turn due to the difference in insolation. Irrespective of elevation and aspect, all the forests studied are regenerating, as indicated by inverse J-shaped density-diameter curves. The elevational pattern of seedling and sapling abundance is explained only by elevation. Whereas other variables (e.g., canopy) are considered to have an important influence on seed germination and seedling establishment, they turn out not to be significant predictors of density of seedlings and saplings. This failure to identify a relationship is probably due to our use of non-parametric test (tree regression analysis) that we used to establish the relationship between density and its potential explanatory variables or due to our selection of 1 standard error rule yielding sub-optimal models for regression trees. Key words: density-diameter curve; regeneration; seedling; sapling; altitude; canopy; Manang Valley DOI: http://dx.doi.org/10.3126/hjs.v6i8.1798 Himalayan Journal of Sciences Vol.6 Issue 8 2010 pp.19-26
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Xu, C., Y. M. Ma, K. Yang, Z. K. Zhu, J. M. Wang, P. M. Amatya e L. Zhao. "Similarities and differences of aerosol optical properties between southern and northern slopes of the Himalayas". Atmospheric Chemistry and Physics Discussions 13, n. 8 (13 agosto 2013): 20961–1002. http://dx.doi.org/10.5194/acpd-13-20961-2013.
Testo completoAbstract (sommario):
Abstract. The Himalayas is located at the southern edge of the Tibetan Plateau, and it acts as a natural barrier for the transport of atmospheric aerosols, e.g. from the polluted regions of South Asia to the main body of the Tibetan Plateau. In this study, we investigate the seasonal and diurnal variations of aerosol optical properties measured at the three Aerosol Robotic Network (AERONET) sites over the southern (Pokhara station and EVK2-CNR station in Nepal) and northern (Qomolangma (Mt. Everest) station for Atmospheric and Environmental Observation and Research, Chinese Academy of Sciences (QOMS_CAS) in Tibet, China) slopes of the Himalayas. While observations at QOMS_CAS and EVK2-CNR can generally be representative of a remote background atmosphere, Pokhara is an urban site with much higher aerosol load due to the influence of local anthropogenic activities. The annual mean of aerosol optical depth (AOD) during the investigated period was 0.06 at QOMS_CAS, 0.04 at EVK2-CNR and 0.51 at Pokhara, respectively. Seasonal variations of aerosols are profoundly affected by large scale atmospheric circulation. Vegetation fires, peaking during April in the Himalayan region and northern India, contribute to a growing fine mode AOD at 500 nm at the three stations. Dust transported to these sites results in an increase of coarse mode AOD during the monsoon season at the three sites. Meanwhile, coarse mode AOD at EVK2-CNR is higher than QOMS_CAS from July to September, indicating the Himalayas blocks the coarse particles carried by the southwest winds. The precipitation scavenging effect is obvious at Pokhara, which can significantly reduce the aerosol load during the monsoon season. Unlike the seasonal variations, diurnal variations are mainly influenced by meso-scale systems and local topography. In general, precipitation can lead to a decrease of the aerosol load and the average particle size at each station. AOD changes in a short time with the emission rate near the emission source at Pokhara, while does not at the other two stations in remote regions. AOD increases during daytime due to the valley winds at EVK2-CNR, while this diurnal variation of AOD is absent at the other two stations. The surface heating influences the local convection, which further controls the vertical aerosol exchange and the diffusion rate of pollutions to the surrounding areas. The Himalayas blocks most of the coarse particles across the mountains. Fine and coarse mode particles are mixed to make atmospheric composition more complex on the southern slope in spring, which leads to the greater inter-annual difference in diurnal cycles of Ångström exponent (AE) at EVK2-CNR than that at QOMS_CAS.
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Sun, Fanglin, Yaoming Ma, Zeyong Hu, Maoshan Li, Gianni Tartari, Franco Salerno, Tobias Gerken, Paolo Bonasoni, Paolo Cristofanelli e Elisa Vuillermoz. "Mechanism of Daytime Strong Winds on the Northern Slopes of Himalayas, near Mount Everest: Observation and Simulation". Journal of Applied Meteorology and Climatology 57, n. 2 (febbraio 2018): 255–72. http://dx.doi.org/10.1175/jamc-d-16-0409.1.
Testo completoAbstract (sommario):
AbstractThe seasonal variability of strong afternoon winds in a northern Himalayan valley and their relationship with the synoptic circulation were examined using in situ meteorological data from March 2006 to February 2007 and numerical simulations. Meteorological observations were focused on the lower Rongbuk valley, on the north side of the Himalayas (4270 m MSL), where a wind profile radar was available. In the monsoon season (21 May–4 October), the strong afternoon wind was southeasterly, whereas it was southwesterly in the nonmonsoon season. Numerical simulations were performed using the Weather Research and Forecasting Model to investigate the mechanism causing these afternoon strong winds. The study found that during the nonmonsoon season the strong winds are produced by downward momentum transport from the westerly winds aloft, whereas those during the monsoon season are driven by the inflow into the Arun Valley east of Mount Everest. The air in the Arun Valley was found to be colder than that of the surroundings during the daytime, and there was a horizontal pressure gradient from the Arun Valley to Qomolangma Station (QOMS), China Academy of Sciences, at the 5200-m level. This explains the formation of the strong afternoon southeasterly wind over QOMS in the monsoon season. In the nonmonsoon season, the colder air from Arun Valley is confined below the ridge by westerly winds associated with the subtropical jet.
33
Adhikari, P. B., A. Adhikari e A. K. Tiwari. "Effects of lightning as a disaster in Himalayan region". BIBECHANA 18, n. 2 (29 maggio 2021): 117–29. http://dx.doi.org/10.3126/bibechana.v18i2.29168.
Testo completoAbstract (sommario):
In Nepal, the main disasters are floods, lightning, fire, epidemics, and landslides. Among the several disasters in the Himalayan region, lightning is an important one. Because of the short distance (about 160 km) between the low land and peak Mount Everest from South to North, there is a variation of about 950C temperature in these regions. The topographical features of the southern slopes and variation of temperature within this short distance influences the features of lightning and in this scenario, we get the positive cloud to ground lightning frequently which is more dangerous for human beings, animals, and property. In the Himalayan region, thunderstorms occur near the mountains due to which more positive charge can easily transfer from cloud to ground. Hence positive lightning occurs in the Himalayan region. The majority of the lightning-affected people are unaware of lightning safety and they should know the measures to protect life and property from lightning hazards. Hence by conducting awareness programs for the people of potential hazard areas, the number of injured people can be reduced as well as electrical, medical, military equipment can be somewhat protected from lightning.
BIBECHANA 18 (2) (2021) 116-128
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Barros, A. P., G. Kim, E. Williams e S. W. Nesbitt. "Probing orographic controls in the Himalayas during the monsoon using satellite imagery". Natural Hazards and Earth System Sciences 4, n. 1 (1 marzo 2004): 29–51. http://dx.doi.org/10.5194/nhess-4-29-2004.
Testo completoAbstract (sommario):
Abstract. The linkages between the space-time variability of observed clouds, rainfall, large-circulation patterns and topography in northern India and the Himalayas were investigated using remote sensing data. The research purpose was to test the hypothesis that cloudiness patterns are dynamic tracers of rainstorms, and therefore their temporal and spatial evolution can be used as a proxy of the spatial and temporal organization of precipitation and precipitation processes in the Himalayan range during the monsoon. The results suggest that the space-time distribution of precipitation, the spatial variability of the diurnal cycle of convective activity, and the terrain (landform and altitudinal gradients) are intertwined at spatial scales ranging from the order of a few kms (1–5km) up to the continental-scale. Furthermore, this relationship is equally strong in the time domain with respect to the onset and intra-seasonal variability of the monsoon. Infrared and microwave imagery of cloud fields were analyzed to characterize the spatial and temporal evolution of mesoscale convective weather systems and short-lived convection in Northern India, the Himalayan range, and in the Tibetan Plateau during three monsoon seasons (1999, 2000 and 2001). The life cycle of convective systems suggests landform and orographic controls consistent with a convergence zone constrained to the valley of the Ganges and the Himalayan range, bounded in the west by the Aravalli range and the Garhwal mountains and in the East by the Khasi Hills and the Bay of Bengal, which we call the Northern India Convergence Zone (NICZ). The NICZ exhibits strong night-time activity along the south-facing slopes of the Himalayan range, which is characterized by the development of short-lived convection (1–3h) aligned with protruding ridges between 1:00 and 3:00 AM. The intra-annual and inter-annual variability of convective activity in the NICZ were assessed with respect to large-scale synoptic conditions, monsoon activity in the Bay of Bengal, and the modulating role of orography. Empirical orthogonal function (EOF) and canonical correlation (CC) analysis suggest that joint modes of variability of monsoon weather and topography, which we call orographic land-atmosphere interactions, modulate the space-time variability of cloudiness in the region. Finally, scaling analysis of cloudiness suggests three different scaling regimes of orographic land-atmosphere interactions: 1) a synoptic-scale regime (≥70-80km); 2) an orographic meso–β regime (30–70km) associated with the succession of wide valleys and bulky terrain features; and 3) an orographic meso–α regime (≤30km) associated with the complex succession of protruding south-facing ridges and narrow valleys that characterize the Himalayan foothills between altitudes of 3000 and 5000m elevations.
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Ghimire, Motilal, e Niroj Timalsina. "Assessment of denudation rate and erosion susceptibility in the upper Tamakoshi basin in the higher Himalayas, Nepal". Geographical Journal of Nepal 14 (10 marzo 2021): 41–80. http://dx.doi.org/10.3126/gjn.v14i0.35548.
Testo completoAbstract (sommario):
The higher rate of slope erosion in the Himalayan basins is contributing to rapid change in landform in the mountainous terrain, which has caused sedimentation, and inundation downstream. The Tamakoshi basin is a trans-boundary river that originates from Tibet and flows through Dolakha and Ramechap districts before joining the Sapta Koshi river. Few studies exist in Nepal attempting to quantify the erosion rate and susceptibility. However, they are scattered and mainly focus on either rill-sheet erosion or landslide only. Hence, this study attempted to estimate slope erosion by applying the Revised Universal Soil Loss Equation (RUSLE), and soil and debris erosion from landslide (2000-2019). Spatially distributed erosion intensity maps derived from the RUSLE model, as well as index-based landslide susceptibility map, were integrated to capture both running water and gravity erosion processes. The novelty of this research is that it examined the soil erosion rate using a process-based model as well as from the soil or rock displaced by the observed landslides over the last 20 years. The study estimated gross annual erosion by running water of 9.1million tons/yr, equivalent to the denudation rate of 3.34 mm/yr. Of these, landslide erosion accounts for 7.6 million ton/yr, i.e., 2.88 mm/yr, this covers about 84% of total slope erosion. High landslide and erosion potential areas are associated with high rainfall, steep slopes, scarps, lower segment of valley side slopes, high relief, and highly fractured and deformed parts of high-grade metamorphic rocks, such as gneiss, quartzite, marbles, migmatite, and granitic gneiss.
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Sarangi, Chandan, Yun Qian, Karl Rittger, Kathryn J. Bormann, Ying Liu, Hailong Wang, Hui Wan, Guangxing Lin e Thomas H. Painter. "Impact of light-absorbing particles on snow albedo darkening and associated radiative forcing over high-mountain Asia: high-resolution WRF-Chem modeling and new satellite observations". Atmospheric Chemistry and Physics 19, n. 10 (27 maggio 2019): 7105–28. http://dx.doi.org/10.5194/acp-19-7105-2019.
Testo completoAbstract (sommario):
Abstract. Light-absorbing particles (LAPs), mainly dust and black carbon, can significantly impact snowmelt and regional water availability over high-mountain Asia (HMA). In this study, for the first time, online aerosol–snow interactions are enabled and a fully coupled chemistry Weather Research and Forecasting (WRF-Chem) regional model is used to simulate LAP-induced radiative forcing on snow surfaces in HMA at relatively high spatial resolution (12 km, WRF-HR) compared with previous studies. Simulated macro- and microphysical properties of the snowpack and LAP-induced snow darkening are evaluated against new spatially and temporally complete datasets of snow-covered area, grain size, and impurity-induced albedo reduction over HMA. A WRF-Chem quasi-global simulation with the same configuration as WRF-HR but a coarser spatial resolution (1∘, WRF-CR) is also used to illustrate the impact of spatial resolution on simulations of snow properties and aerosol distribution over HMA. Due to a more realistic representation of terrain slopes over HMA, the higher-resolution model (WRF-HR) shows significantly better performance in simulating snow area cover, duration of snow cover, snow albedo and snow grain size over HMA, as well as an evidently better atmospheric aerosol loading and mean LAP concentration in snow. However, the differences in albedo reduction from model and satellite retrievals is large during winter due to associated overestimation in simulated snow fraction. It is noteworthy that Himalayan snow cover has high magnitudes of LAP-induced snow albedo reduction (4 %–8 %) in pre-monsoon seasons (both from WRF-HR and satellite estimates), which induces a snow-mediated radiative forcing of ∼30–50 W m−2. As a result, the Himalayas (specifically the western Himalayas) hold the most vulnerable glaciers and mountain snowpack to the LAP-induced snow darkening effect within HMA. In summary, coarse spatial resolution and absence of snow–aerosol interactions over the Himalayan cryosphere will result in significant underestimation of aerosol effects on snow melting and regional hydroclimate.
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Rawat, Yashwant S., Vikram S. Negi, Ihab Mohamed Moussa, Wajid Zaman e Hosam O. Elansary. "Diversity, Distribution and Vegetation Assessment of Woody Plant Species in the Cold Desert Environment, North-Western Himalaya, India". Sustainability 15, n. 13 (2 luglio 2023): 10429. http://dx.doi.org/10.3390/su151310429.
Testo completoAbstract (sommario):
The species richness, distribution and community structure in cold desert regions across the world are poorly understood because of their inaccessibility and remoteness. Similarly, the structure and composition of forest resources, including other management units (i.e., agroforestry and forestry systems), have hardly been studied in the cold desert of the Lahaul valley. However, such information is a prerequisite to understanding the trends and changes in the vegetation distribution under global climate change scenarios, especially considering the sensitivity of plant species in high-altitude areas of the Himalayan region. High anthropogenic activity has exerted tremendous pressure on available forest resources, including other management units in the cold desert of the Lahaul valley. Standard ecological methods were used to obtain an ecological (i.e., status, structure, composition and vegetation patterns) understanding of the region for biodiversity conservation and environmental sustainability. The present study was aimed at understanding the trend, structure and composition of plant species in the cold desert region of the western Himalaya. A total of 64 species (27 trees and 37 shrubs) of vascular plants were recorded in the present study. Tree diversity demonstrated greater variation along the gradients and slope aspects. Salix fragilis trees, with a 102 tree ha−1 density and a few trees of Populus nigra, were found to be sparsely distributed under the agroforestry system on the south-facing slopes in Khoksar. In Jahlma, Salix fragilis grew in an agroforestry system with a density of 365 tree ha−1. However, in Hinsa, Juniperus polycarpos was a dominant tree species in the agroforestry system, with a density of 378 tree ha−1. On the north-facing slopes in Kuthar, a higher number of trees and bushes were present due to natural regeneration maintained by farmers along the edges of terraced agricultural fields. The south-facing slopes showed a relatively lower species richness and diversity as compared to north-facing slopes at similar locations due to relatively less favourable growth conditions under sun-exposed, extremely xeric soil conditions. The highest level of species turnover was found between the altitudes of 2400 m and 3000 m. Betula utilis showed the highest adaptability at higher altitudes (>3500 m). The vegetation analysis results and information generated in the present study are useful for gaining an ecological understanding of the cold desert ecosystem in the Lahaul valley. Sustainable forest resource management, including other management units (e.g., agroforestry and forestry systems), is crucial for improving the vegetation pattern, structure and function of the cold desert ecosystem, thereby contributing to climate change mitigation, adaptation, biodiversity and ecosystem service conservation.
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Singh, Rahaman, Sharma, Laluraj, Patel, Pratap, Gaddam e Thamban. "Moisture Sources for Precipitation and Hydrograph Components of the Sutri Dhaka Glacier Basin, Western Himalayas". Water 11, n. 11 (26 ottobre 2019): 2242. http://dx.doi.org/10.3390/w11112242.
Testo completoAbstract (sommario):
Himalayan glaciers are the major source of fresh water supply to the Himalayan Rivers, which support the livelihoods of more than a billion people living in the downstream region. However, in the face of recent climate change, these glaciers might be vulnerable, and thereby become a serious threat to the future fresh water reserve. Therefore, special attention is required in terms of understanding moisture sources for precipitation over the Himalayan glaciers and the hydrograph components of streams and rivers flowing from the glacierized region. We have carried out a systematic study in one of the benchmark glaciers, “Sutri Dhaka” of the Chandra Basin, in the western Himalayas, to understand its hydrograph components, based on stable water isotopes (δ18O and δ2H) and field-based ablation measurements. Further, to decipher moisture sources for precipitation and its variability in the study region, we have studied stable water isotopes in precipitation samples (rain and snow), and performed a back-trajectory analysis of the air parcel that brings moisture to this region. Our results show that the moisture source for precipitation over the study region is mainly derived from the Mediterranean regions (>70%) by Western Disturbances (WDs) during winter (October–May) and a minor contribution (<20%) from the Indian Summer Monsoon (ISM) during summer season (June–September). A three-component hydrograph separation based on δ18O and d-excess provides estimates of ice (65 ± 14%), snowpack (15 ± 9%) and fresh snow (20 ± 5%) contributions, respectively. Our field-based specific ablation measurements show that ice and snow melt contributions are 80 ± 16% and 20 ± 4%, respectively. The differences in hydrograph component estimates are apparently due to an unaccounted snow contribution ‘missing component’ from the valley slopes in field-based ablation measurements, whereas the isotope-based hydrograph separation method accounts for all the components, and provides a basin integrated estimate. Therefore, we suggest that for similar types of basins where contributions of rainfall and groundwater are minimal, and glaciers are often inaccessible for frequent field measurements/observations, the stable isotope-based method could significantly add to our ability to decipher moisture sources and estimate hydrograph components.
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Vishal, V., T. Siddique, Rohan Purohit, Mohit K. Phophliya e S. P. Pradhan. "Hazard assessment in rockfall-prone Himalayan slopes along National Highway-58, India: rating and simulation". Natural Hazards 85, n. 1 (20 settembre 2016): 487–503. http://dx.doi.org/10.1007/s11069-016-2563-y.
Testo completo
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Pradhan, S. P., Vikram Vishal e T. N. Singh. "Finite element modelling of landslide prone slopes around Rudraprayag and Agastyamuni in Uttarakhand Himalayan terrain". Natural Hazards 94, n. 1 (15 giugno 2018): 181–200. http://dx.doi.org/10.1007/s11069-018-3381-1.
Testo completo
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Mishra, V. D., J. K. Sharma e R. Khanna. "Review of topographic analysis methods for the western Himalaya using AWiFS and MODIS satellite imagery". Annals of Glaciology 51, n. 54 (2010): 153–60. http://dx.doi.org/10.3189/172756410791386526.
Testo completoAbstract (sommario):
AbstractThe topographic effects of differential terrain illumination in optical satellite imagery of rugged mountainous regions have serious consequences for qualitative and quantitative analysis for various snow applications. Therefore, effective removal or minimization of topographic effects is necessary in satellite image data of mountainous regions. Different methods for topographic corrections, including C-correction, Minnaert corrections (including slope) and slope-matching method, are analysed in the context of snow reflectance. Combination of dark-object subtraction models DOS1 and DOS3 is used for image-based atmospheric corrections while considering the effect of Rayleigh scattering on the transmissivity in different spectral bands of AWiFS and MODIS image data. The performance of different models is evaluated using (1) visual analysis, (2) change in snow reflectance on sunny and shady slopes after the corrections, (3) validation with in situ observations and (4) graphical analysis. The results show that the slope-matching technique could eliminate most of the shadowing effects in Himalayan rugged terrain and correctly estimate snow reflectance from AWiFS and MODIS imagery. The validation of results with in situ observations for both types of imagery suggests that all other methods significantly underestimate reflectance values after the corrections.
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Kumar, Luitel Keshar, V. Thirukumaran e Luitel Homnath. "Estimation of soil overburden thickness/depth of rock strata using geo-physical survey at Himalayan region". Journal of Geology, Geography and Geoecology 31, n. 4 (10 gennaio 2023): 659–67. http://dx.doi.org/10.15421/112262.
Testo completoAbstract (sommario):
Estimation of soil overburden and depth of competent strata for construction of infrastructures in hilly terrain is a challenging job for engineers. Modern technologies like Electrical Resistivity Survey (ERS) techniques with site geological mapping have been carried out at the ridge area near Palace, Gangtok. Two independent 2D-electrical resistivity surveys profile sections using hybrid Schlumberger-Wenner method were conducted along the ridge line trending in the North-South direction. The ERS profile sections were taken on both the slopes of the ridge along its eastern and western flanks. With the collective information from field and geo-technical data, a comparatively stable slope has been identified with respect to geological conditions in the present work, which focuses on the vulnerable slope failure with respect to slope direction, local geological condition, depth of competent strata, thickness of soil overburden, water saturation zones and resistivity of the materials. Diamond core drilling of 15meters each was carried out at both the flanks of the slope to understand the sub-surface strata and correlate it with resistivity data generated by ERS survey. The result indicates that Sandy/silty soil with flakes of mica having resistivity of 107 ohm-m and weathered mica schist having resistivity more than 300 ohm-m in the present study area. Geological mapping in 1:3000 scale was carried in the area demarcation with various litho-units and rock type. The area is characterized by medium grade metamorphic rock sequence represented in the area by mica schist having dip of foliations towards NE direction and three sets of joint planes. The geometry of the rock orientation and slope direction plays a vital role for determining the overall stability condition of the area. The present study will provide technical input for structural engineers to design the structures in such geological conditions. Further, the thickness of overburden estimated from ERS has been validated by drilling data.
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Joshi, B. R., L. M. Gibbons e D. E. Jacobs. "Ostertagia nianqingtanggulaensis K'ung & Li, 1965 (Nematoda: Trichostrongyloidea) from sheep and goats at high altitudes in Nepal". Journal of Helminthology 71, n. 1 (marzo 1997): 21–28. http://dx.doi.org/10.1017/s0022149x00000742.
Testo completoAbstract (sommario):
AbstractThe trichostrongyloid nematode Ostertagia nianqingtanggulaensis K'ung & Li, 1965, previously recorded only from sheep in Tibet, is redescribed and is shown to be a common parasite of both sheep and goats at higher altitudes in the Himalayan foothills of western Nepal. Herbage examination indicated that infective larvae can overwinter on snow covered slopes. Use of tracer animals confirmed that migratory flocks are exposed to infection when grazing on alpine pastures during the summer months. In contrast, nearby non-migratory flocks kept at lower altitudes did not harbour O. nianqingtanggulaensis and tracer animals grazed with these flocks did not become infected with this species.
44
Lau, William, e Kyu-Myong Kim. "Impact of Snow Darkening by Deposition of Light-Absorbing Aerosols on Snow Cover in the Himalayas–Tibetan Plateau and Influence on the Asian Summer Monsoon: A Possible Mechanism for the Blanford Hypothesis". Atmosphere 9, n. 11 (12 novembre 2018): 438. http://dx.doi.org/10.3390/atmos9110438.
Testo completoAbstract (sommario):
The impact of snow darkening by deposition of light-absorbing aerosols (LAAs) on snow cover over the Himalayas–Tibetan Plateau (HTP) and the influence on the Asian summer monsoon were investigated using the NASA Goddard Earth Observing System Model Version 5 (GEOS-5). The authors found that during April–May–June, the deposition of LAAs on snow led to a reduction in surface albedo, initiating a sequence of feedback processes, starting with increased net surface solar radiation, rapid snowmelt in the HTP and warming of the surface and upper troposphere, followed by enhanced low-level southwesterlies and increased dust loading over the Himalayas–Indo-Gangetic Plain. The warming was amplified by increased dust aerosol heating, and subsequently amplified by latent heating from enhanced precipitation over the Himalayan foothills and northern India, via the elevated heat pump (EHP) effect during June–July–August. The reduced snow cover in the HTP anchored the enhanced heating over the Tibetan Plateau and its southern slopes, in conjunction with an enhancement of the Tibetan Anticyclone, and the development of an anomalous Rossby wave train over East Asia, leading to a weakening of the subtropical westerly jet, and northward displacement and intensification of the Mei-Yu rain belt. The authors’ results suggest that the atmosphere-land heating induced by LAAs, particularly desert dust, plays a fundamental role in physical processes underpinning the snow–monsoon relationship proposed by Blanford more than a century ago.
45
Shi, Zhen-ming, Megh Raj Dhital, Yuan-yuan Zhou, Wei-ran Liu, Qing-zhao Zhang e Dan-xuan Xue. "Engineering geology of cross-Himalayan railway alignment and its preliminary design". Journal of Nepal Geological Society 56, n. 1 (28 giugno 2018): 49–54. http://dx.doi.org/10.3126/jngs.v56i1.22699.
Testo completoAbstract (sommario):
The Belt-and-Road initiative foresees the construction of transportation routes across continents. One of such railway routes is planned from Tibet (China) through the Himalayan Range to Nepal and India, and envisaged to be one of the most important economic corridors. Based on the field investigation, this paper analyses the engineering geological conditions along the proposed route and proposes a preliminary design of the alignment. The alignment starts from Dingri (Tingri) via Jilong from Tibet and ends in Kathmandu, with a total length of 357 km. Based on the geological and geomorphic characteristics, the alignment can be divided into five zones: the mid mountain and wide valley, mid mountain and narrow valley, alluvial fans, tunnel crossing, and, respectively. The railway alignment encounters glaciers, snow and rock avalanches, collapses, landslides, outburst floods and debris flows. There are also many faults, folds and other geological structures together with steep and extensive slopes and long tunnels with a high overburden.
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KATAEV, BORIS M., e JOACHIM SCHMIDT. "Brachypterous ground beetles of the Trichotichnus subgenus Bottchrus Jedlička (Coleoptera, Carabidae) from the Himalaya, with description of fifteen new species". Zootaxa 4323, n. 3 (22 settembre 2017): 301. http://dx.doi.org/10.11646/zootaxa.4323.3.1.
Testo completoAbstract (sommario):
The paper deals with the taxonomy of brachypterous species of the subgenus Bottchrus Jedlička, 1935 of the genus Trichotichnus Morawitz, 1863 occurring in the Himalayan region. The following new species are described: T. (B.) baglungensis sp. n. from the Baglung Lekh mountain range, Baglung District, western Central Nepal; T. (B.) parvulus sp. n. from Mt. Panchhase and the Krapa Danda mountain range, Kaski District, western Central Nepal; T. (B.) bubsaensis sp. n. from the eastern slope of the middle Dudh Koshi Valley near Bubsa, Solu Khumbu District, eastern Central Nepal; T. (B.) schawalleri sp. n. from the western slope of the Arun Valley, Bhojpur District, East Nepal; T. (B.) obliquebasalis sp. n. from the Khimti Khola Valley near Shivalaya, Dolakha District, eastern Central Nepal; T. (B.) panchhaseensis sp. n. from Mt. Panchhase, Kaski District, western Central Nepal; T. (B.) siklesensis sp. n. from the Sikles mountain range on the southern slope of Annapurna Peak II, western Central Nepal; T. (B.) pusillus sp. n. from the south-western slopes of Manaslu Himal (Bara Pokhari Lekh and Dudh Pokhari Lekh mountain ranges), and from the south-eastern slope of Annapurna Himal (Telbrung Danda mountain range), Lamjung District, western Central Nepal; T. (B.) ganeshensis sp. n. from the south-western slope of Ganesh Himal, Nuwakot District, Central Nepal; T. (B.) minutus sp. n. from the mountains surrounding the Kathmandu Valley (Shivapuri Lekh, Mt. Phulchoki), Central Nepal; T. (B.) gupchiensis sp. n. from the Gupchi Danda mountain range on the south-eastern slope of Manaslu Himal, Gorkha District, western Central Nepal; T. (B.) brancuccii sp. n. from the southern slope of the Helambu mountain range, Sindhupalchok District, Central Nepal; T. (B.) manasluensis sp. n. from the Bara Pokhari Lekh mountain range on the south-western slope of Manaslu Himal, Lamjung District, western Central Nepal; T. (B.) sikkimensis sp. n. from Pelling near Geyzing, West Sikkim, India; T. (B.) martensi sp. n. from the western slopes of the Singalila mountain range, Taplejung District, East Nepal. The following four species are redescribed: brachypterous T. (B.) holzschuhi Kirschenhofer, 1992; T. (B.) cyanescens Ito, 1998; T. (B.) hingstoni Andrewes, 1930; and dimorphic T. (B.) birmanicus Bates, 1892; and new data on their distribution are provided. The lectotype is designated for T. hingstoni Andrewes, 1930. The following two new synonyms are proposed: Trichotichnus birmanicus Bates, 1892 = T. (Bellogenus) probsti Kirschenhofer, 1992, syn. n., and T. hingstoni Andrewes, 1930 = T. (Pseudotrichotichnus) curvatus Ito, 1996, syn. n. The brachypterous and dimorphic species of Bottchrus known from the Himalaya are divided into eight informal groups based mostly on the degree of reduction of hindwings and the configuration of the median lobe of the aedeagus, and their relationships are briefly discussed. The distributional data of all these species are mapped.
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Siddque, T., e S. P. Pradhan. "Stability and sensitivity analysis of Himalayan road cut debris slopes: an investigation along NH-58, India". Natural Hazards 93, n. 2 (17 aprile 2018): 577–600. http://dx.doi.org/10.1007/s11069-018-3317-9.
Testo completo
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Wagnon, Patrick, Anurag Linda, Yves Arnaud, Rajesh Kumar, Parmanand Sharma, Christian Vincent, Jose George Pottakkal et al. "Four years of mass balance on Chhota Shigri Glacier, Himachal Pradesh, India, a new benchmark glacier in the western Himalaya". Journal of Glaciology 53, n. 183 (2007): 603–11. http://dx.doi.org/10.3189/002214307784409306.
Testo completoAbstract (sommario):
Little is known about the Himalayan glaciers, although they are of particular interest in terms of future water supply, regional climate change and sea-level rise. In 2002, a long-term monitoring programme was started on Chhota Shigri Glacier (32.2° N, 77.5° E; 15.7 km2, 6263–4050 ma.s.l., 9 km long) located in Lahaul and Spiti Valley, Himachal Pradesh, India. This glacier lies in the monsoon–arid transition zone (western Himalaya) which is alternately influenced by Asian monsoon in summer and the mid-latitude westerlies in winter. Here we present the results of a 4 year study of mass balance and surface velocity. Overall specific mass balances are mostly negative during the study period and vary from a minimum value of –1.4 m w.e. in 2002/03 and 2005/06 (equilibrium-line altitude (ELA) ∼5180 m a.s.l.) to a maximum value of +0.1 m w.e. in 2004/05 (ELA 4855 m a.s.l.). Chhota Shigri Glacier seems similar to mid-latitude glaciers, with an ablation season limited to the summer months and a mean vertical gradient of mass balance in the ablation zone (debris-free part) of 0.7mw.e.(100 m)–1, similar to those reported in the Alps. Mass balance is strongly dependent on debris cover, exposure and the shading effect of surrounding steep slopes.
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Chen, W., T. Doko, C. Liu, T. Ichinose, H. Fukui, Q. Feng e P. Gou. "Changes in Rongbuk lake and Imja lake in the Everest region of Himalaya". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-2 (18 dicembre 2014): 259–66. http://dx.doi.org/10.5194/isprsarchives-xl-2-259-2014.
Testo completoAbstract (sommario):
The Himalaya holds the world record in terms of range and elevation. It is one of the most extensively glacierized regions in the world except the Polar Regions. The Himalaya is a region sensitive to climate change. Changes in the glacial regime are indicators of global climate changes. Since the second half of the last century, most Himalayan glaciers have melted due to climate change. These changes directly affected the changes of glacial lakes in the Himalayan region due to the glacier retreat. New glacial lakes are formed, and a number of them have expanded in the Everest region of the Himalayas. This paper focuses on the two glacial lakes which are Imja Lake, located at the southern slope, and Rongbuk Lake, located at the northern slope in the Mt. Everest region, Himalaya to present the spatio-temporal changes from 1976 to 2008. Topographical conditions between two lakes were different (Kruskal-Wallis test, <i>p</i> < 0.05). Rongbuk Lake was located at 623 m higher than Imja Lake, and radiation of Rongbuk Lake was higher than the Imja Lake. Although size of Imja Lake was larger than the Rongbuk Lake in 2008, the growth speed of Rongbuk Lake was accelerating since 2000 and exceeds Imja Lake in 2000–2008. This trend of expansion of Rongbuk Lake is anticipated to be continued in the 21st century. Rongbuk Lake would be the biggest potential risk of glacial lake outburst flood (GLOF) at the Everest region of Himalaya in the future.
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Alam, Nuzhat Mir, Hamayun Shaheen, Muhammad Manzoor, Tan Tinghong, Muhammad Arfan e Muhammad Idrees. "Spatial Distribution and Population Structure of Himalayan Fir (Abies pindrow (Royle ex D.Don) Royle) in Moist Temperate Forests of the Kashmir Region". Forests 14, n. 3 (27 febbraio 2023): 482. http://dx.doi.org/10.3390/f14030482.
Testo completoAbstract (sommario):
Abies pindrow is a keystone tree species of temperate forests in the Himalayan range with immense ecological significance. The current study was designed to investigate the spatial distribution, population structure, associated flora, and sustainability of Abies pindrow in the temperate forests of Azad Jammu and Kashmir (AJK), Pakistan. Vegetation data were collected from 48 forest sites distributed in six districts of AJK with respect to the geography, microclimates, and vegetation structure by employing a systematic quadrate-based methodology. Abies pindrow populations were characterized by an average stem density of 183.9 trees/ha with an average basal area cover of 789 cm. A. pindrow populations showed a regeneration value of 555.6 seedlings/ha. A digital elevation model revealed that A. pindrow exhibited a large extent of distribution in an altitudinal range of 1800–3400 m. GIS analysis identified that north-facing slopes with a moderate degree of slope steepness constitutes the preferred habitat of the species in the Kashmir mountains. A floristic analysis revealed that a total of 282 species from 74 plant families comprised the associated flora of A. pindrow-dominated forests with Pinus wallichiana, Picea smithiana, Aesculus indica, and Viburnum grandiflorum as codominant companion species. A. pindrow forests exhibited significant levels of species diversity and richness with average values of Simpson’s diversity as 0.94, Shannon’s diversity as 3.09, species richness as 1.45, and maturity index value as 45.9%. The A. pindrow populations in the study area were found to be subjected to significant deforestation pressure along with overgrazing and erosion impacts. Results provide valuable scientific information for the conservation management of A. pindrow populations, ensuring the sustainability of temperate forest ecosystems in the Western Himalayan region of Kashmir.