Nepal Himalaya Research Articles

Drought characteristics over Nepal Himalaya and their relationship with climatic indices

AbstractUnderstanding drought characteristics is vital for sustainable societal and ecosystem functioning, especially in ongoing climate change. The study investigates the drought characteristics over the Nepal Himalaya using the standardized precipitation index (SPI) based on monthly precipitation data from 220 ground stations between 1980 and 2016 at seasonal and annual timescales. The results show that occurrences of drought are more frequent after the 2000s, intensifying their severity and duration. The cumulative probabilities of short‐term (SPI3) and long‐term (SPI12) drought during the period 1980–2016 were 17.1% and 23.5%, respectively. The short‐term drought over Nepal occurred with an average duration of 2.8 months and a severity of −4.3, whereas for long‐term drought the duration and severity were 8.6 months and −13.9, respectively. Meanwhile, the seasonal drought shows that the spring and autumn drought events were slightly higher than summer and winter drought. The wavelet power spectrum shows the variability signals of winter, spring and summer drought were 2–8 and 8–16 years; however, the autumn drought index only varied at 2–8 years. The NINO3.4 is the primary controlling mode of variability for summer and annual drought, whereas the dipole moment index (DMI) is used for the autumn drought at an interannual timescale. The decadal variability of summer and annual drought is linked with the Pacific Decadal Oscillation, whereas winter and spring drought are linked to the Arctic Oscillation. Furthermore, the study contributes to the understanding of the drought characteristics and its controlling factors of variability over Nepal.

Seismic Imaging of the Crust Beneath Arunachal Himalaya

AbstractWe present the first high‐resolution seismic images of the crust beneath the Arunachal Himalaya, using 22,525 high quality teleseismic receiver functions (RFs). Data from 32 broadband seismic stations deployed in the Arunachal Himalaya during 2010–2016 is used for this purpose. In addition, data from the HIMNT, SIKKIM, Hi‐CLIMB, and Geodynamics ANd Seismic Structure of the Eastern‐Himalaya Region networks are used to investigate along strike variations in the crustal architecture of the Eastern Himalayan mountain belt. Common Conversions Point stacks constructed using RFs from 203 seismic stations along various S‐N profiles reveal lateral variations in the crustal structure. We observe, (a) a less complex crust beneath the Arunachal Himalaya compared to that in the Nepal and Sikkim Himalaya (b) a highly deformed layer running parallel to the Main Himalayan Thrust (c) intermittent anisotropic low velocity layer in the middle crust (d) that the crustal thickness estimates are in close agreement with those in other segments of the Eastern Himalaya (40–60 kms) (e) no prominent signatures of a mid‐crustal ramp as observed in the Nepal Himalaya. The geometry of the crust in the Eastern Himalayan segments appears less complex compared to the Central Himalayan segments. The presence of strong anisotropy associated with the low velocity layer at depths of 20–30 km suggests a mechanically weak middle crust beneath Arunachal Himalaya. Attributing these anisotropic signatures to the channel flow model appears contentious.

Characterizations Of Water Quality In West-Seti and Tamor River Basins, Nepal

This study presents the geochemical composition and water quality of waters in the West-Seti and Tamor River basins in Nepal Himalaya with the aim to reveal their hydrochemical characteristics and to evaluate the water quality. Water samples were collected from 18 sites of the rivers in the pre-monsoon season and analysed the physicochemical parameters to characterize their quality. The parameters- temperature, pH, conductivity, and total dissolved solids were measured in the field, while the major ions (Na+, Ca2+, Mg2+, Si4+, SO42−, NO3−, HCO3−, Cl−, and F−) were analyzed in the laboratory. Overall results of physicochemical parameters revealed that the ionic strength is much distinct; however, the waters are chemically pure in both the river basins with very less electrical conductivity (<250 µS/cm) and total dissolved solids (<120 mg/L). Bicarbonate (HCO3−) has a significant correlation with Ca2+ and Mg2+ suggesting carbonate rock weathering as the dominant geochemical process in both of the basins. The concentrations of Ca2+, Mg2+, and HCO3− in the water of the West-Seti is relatively higher than the waters in the Tamor River basin. Mostly, the geochemical facies of both the rivers are characterized by the Ca-Mg-HCO3- type (88.9%), with dominant carbonate dominated lithology. However, hydrochemical facies clearly suggested spatial discrimination between two basins with dominant geogenic signatures as Ca-SO4-Cl type water facies are also reported from the Tamor River basin. The results exhibited that the concentrations of measured parameters were relatively very low and within the WHO guideline values and currently under a safe level of the water quality for drinking and ecosystem health perspectives; however, further in-depth research is recommended in the periodic basis to assess traces of climate change imprints, and anthropogenic interferences for more consistent and reliable dataset. The findings of this study could be useful for the water quality management in the glacier-fed Himalayan River basins.

Fluid Flow and Leakage Assessment Through an Unlined/Shotcrete Lined Pressure Tunnel: A Case from Nepal Himalaya

The use of unlined/shotcrete lined pressure tunnels and shafts are cost-effective solutions for a hydropower project and are being implemented worldwide. To implement this concept, the ground conditions at the area of concern should be favorable regarding minimum principal stress magnitude, which should be higher than hydrostatic water head acting on the tunnel periphery. In addition, the rock mass should be relatively unjointed or joints in the rock mass should be relatively tight. Among the most important issues in the design of unlined/shotcrete lined pressure tunnels is the extent of hydraulic jacking and water leakage out of the tunnel during operation. This manuscript first presents fluid flow and potential hydraulic jacking assessment of two selected locations of the headrace tunnel of Upper Tamakoshi Hydroelectric Project (UTHP) in Nepal using the UDEC. It is noted here that the 7960 m long headrace tunnel will experience a hydrostatic water head that will vary from 2.9 to 11.5 bars (0.29–1.15 MPa). The headrace tunnel is supported by sprayed concrete (shotcrete) in combination with systematic rock bolts in the tunnel walls and crown. The invert of the tunnel and few hundred meters downstream end (at surge shaft area) of the headrace tunnel is being concrete lined after the completion of all other works. The qualitative fluid flow assessment carried out using UDEC indicated considerable pressure built-up in the joint systems suggesting potential hydraulic jacking. This was especially the case at the downstream segment (downstream from chainage 7100 m) of the headrace tunnel. The manuscript further presents the quantitative results of water leakage estimation from the headrace tunnel carried out using Panthi (Panthi KK (2006) Analysis of engineering geological uncertainties related to tunnelling in Himalayan rock mass conditions. PhD Thesis, NTNU, Trondheim, Norway;Panthi, Note on estimating specific leakage using Panthi’s approach, NTNU, Trondheim, 2010;) approach. The leakage assessment carried out indicated an average specific leakage of about 2.5 l/min/m tunnel, which may result in over 210 l/s leakage from the headrace tunnel. The evaluation also indicated that the outer reach (860 m downstream segment) of the headrace tunnel after chainage 7100 m seems extremely vulnerable and over 80 l/s water leakage may occur only from this headrace tunnel segment during operation of the hydropower plant.

Interdisciplinary Approaches to Reconstructing Early Population History in the High Himalayas of Nepal

Anthropological research in the high-elevation regions of northwestern Nepal offers insights into the populationhistory of the Himalayan arc through a multi- and interdisciplinary approach that includes not only archaeologicaldata and historic and ethnographic accounts but also genomic, isotopic, and bioarchaeologicaldata, as well as innovative use of thermal niche modeling for paleoclimate reconstruction. Together these linesof evidence have allowed us to address project questions about human settlement into the region, including(1) sources of population movements into high-elevation environments of the Himalayan arc and (2) bioculturaladaptations to high-mountain environments. In this paper we compare research at several communalmortuary sites, each with a rich assemblage of material culture and human burials: Mebrak (400 B.C.–A.D. 50),Kyang (400–175 B.C.), and Samdzong (A.D. 450–650), as well as intriguing insights from finds in the earlier (ca.1250–450 B.C.) sites of Lubrak, Chokhopani, and Rhirhi. Our genomic findings demonstrate population originsfrom the Tibetan plateau, despite South Asian material culture recovered in early sites. Bioarchaeological findingsof low frequencies of non-specific stress and trauma indicate successful biocultural adaptation to highaltitudeconditions of hypoxia, cold, and low resource availability, potentially through buffering from exchangenetworks and local cultural practices, alongside high-altitude selected alleles. An integrative, multidisciplinaryapproach thus offers significantly greater opportunities for developing a more nuanced understanding of thepast processes of migration, settlement, and biocultural adaptation in the region.
 La investigación antropológica de las alturas del noroeste de Nepal nos proporciona conocimientos de la historiade la población del arco Himalaya a través de un enfoque multidisciplinario e interdisciplinario que incluyeno solamente datos arqueológicos y relatos históricos y etnográficos, sino también datos genómicos, isotópicos,y bioarqueológicos, tanto como uso innovador del modelado del nicho térmico para la reconstrucción paleoclimática.En conjunto, estas líneas de evidencia nos han permitido abordar temas sobre el asentamiento humanade la región, como: (1) los orígenes del movimiento hacia ambientes en las alturas del arco del Himalaya;y (2) las adaptaciones bioculturales necesarias para vivir en las alturas. En este artículo comparamos las investigacionesde varios mortuorios comunales que ofrecen conjuntos abundantes de entierros humanos y artefactosrelacionados: Mebrak (400 a.C.–d.C. 50), Kyang (400–175 a.C.), and Samdzong (d.C. 450–650), así como loshallazgos intrigantes de sitios anteriores (ca. 1250–450 a.C.) de Lubrak, Chokhopani, y Rhirhi. Nuestros datosgenómicos sugieren orígenes de le población del altiplano tibetano, a pesar del material que deriva del sur de Asia que se ha recuperado de los sitios mas tempranos. Los hallazgos bioarqueológicos demuestran niveles bajosde estrés y trauma inespecífico, y sugieren éxito en adaptación biocultural, a pesar de las condiciones de hipoxia,frio, y los recursos escasos en este ambiente. Es posible que alelos seleccionados a las alturas, junto con sistemasde intercambio y las costumbres locales contribuyeron al éxito de la adaptación. Por lo tanto, un enfoque multidisciplinarioque integra todas las evidencias ofrece una comprensión mas detallada de los procesos de migración,asentamiento, y adaptación biocultural de la región.

Will climate change impact distribution of bats in Nepal Himalayas? A case study of five species

Nepal Himalayas combine Oriental and Sino-Japanese zoogeographic realms as well as those of the eastern and western Himalayas. Physiography coupled with the diverse local climates has enriched the biodiversity of the Nepal Himalayas. The order Chiroptera constitutes more than 25% of the mammalian fauna and forms the most speciose group of mammals in Nepal, where bats are recorded within a wide range of elevations from 64m to 4154m. Climate variation in the past has been observed and projected change has been predicted, and an evaluation of the climate change impact on biodiversity and habitats has been initiated. However, none of the studies has assessed the impact of climate change on bats in the Himalayan range including Nepal, despite bats represent the largest mammalian group in the country. Through Species Distribution Modelling (SDM), we describe the present distribution range for five common species, further assess their response to future climatic changes. Specifically, the occurrence of bats against 10 environmental variables were projected under different climate scenarios; present, Representative Concentration Pathways (RCPs) 4.5 and 8.5 for 2050 and 2070 deploying maximum entropy modeling (MaxEnt). We prepared predicted distribution range maps and estimated area using Arc GIS 10.7.1. Among 10 uncorrelated bioclimatic variables, six contribute to the SDM significantly. Annual precipitation (bio12) is the most common variable for all five species. Two species shows wider present distribution ranges compared to other three. Under the climate change scenarios, although predictions varied among species, similar trends of the range shifting toward northern latitudes and higher elevations are observed. Since the larger part of the current potential distribution range lies outside protected areas, a landscape level conservation approach prioritizing bat conservation is needed. Future surveys should target ground truthing in the western region of the country.

A Study on Distribution, Habitat Use and Conservation Status of Himalayan Musk Deer (<i>Moschus chrysogaster) </i>in Askot Wildlife Sanctuary, India

The population of Himalayan musk deer (Moschus leucogaster) synonym Moschus chrysogaster has declined in recent decades and reached an endangered status in its distribution range. The distribution of Himalayan musk deer is very restrictive to Himalayas of Northern India, Nepal, Bhutan and China hence has low population. Musk deer family is being hunted for their musk pod due to high demand in international markets specially in China and North East Asia for their cosmetic and pharmaceutical use. Due to its habitat loss and large scale poaching the species has become endangered. The species is nocturnal, crepuscular and elusive which makes it difficult to study its distribution and habitat use pattern. The present study was carried out in Dharchula range (about 100 sq. km) in Askot wildlife sanctuary (WLS), Uttarakhand, India from August 2017 to May 2019. We used trail sampling and silent drive count method to estimate the distribution, abundance, and habitat use pattern. A total 63 trail transects and 8 Silent Count Drive (SDC) walks were laid in fir mixed, temperate mixed, birch mixed and pure birch forest at different aspect, slope and elevation. We recorded 10 individuals and 39 pellet groups on 63 trail and 8 SDC walks totaling 169 km effort registering an overall encounter rate of 1.18±0.20 individuals/km. We used mixed-effect models to characterize relationships between deer presence-absence data and habitat variables. The study confirmed that musk deer uses fixed defecation sites at higher elevations (3,000-4,300 m) throughout seasons and years. This species was found to use slope ranging between 20° and 55° and were found most abundant between 30° and 45° slope. The largest fraction of musk deer presence was observed in South west aspect and lowest in Northern aspect. The birch mixed forest recorded highest proportion of total musk deer followed by fir mixed forest. The distribution of musk deer was concentrated between 3,500 to 4,000 m a.s.l. A significant difference in density estimates of Himalayan musk deer was observed across the seasons. The encounter rate was higher 1.39±0.13 during autumn and low 0.66±0.22 during winter. It was observed that the species have suffered heavy decline in population in Askot WLS due to large scale collection of a medicinal fungus (Ophiocordyceps sinensis) locally called Keeda Jadi. Recently Ophiocordyceps sinensis also declared as vulnerable species by IUCN due to over exploitation of this fungus in this region. There is an urgent need for conservation plan for musk deer by strengthening the existing local institutional mechanism such as Van Panchayat and Gram Panchayat and integrating the interest of local community in sharing of benefits of the resources generated from the forest.

Insights on the Impacts of Hydroclimatic Extremes and Anthropogenic Activities on Sediment Yield of a River Basin

Streamflow and sediment flux variations in a mountain river basin directly affect the downstream biodiversity and ecological processes. Precipitation is expected to be one of the main drivers of these variations in the Himalayas. However, such relations have not been explored for the mountain river basin, Nepal. This paper explores the variation in streamflow and sediment flux from 2006 to 2019 in central Nepal’s Kali Gandaki River basin and correlates them to precipitation indices computed from 77 stations across the basin. Nine precipitation indices and four other ratio-based indices are used for comparison. Percentage contributions of maximum 1-day, consecutive 3-day, 5-day and 7-day precipitation to the annual precipitation provide information on the severity of precipitation extremeness. We found that maximum suspended sediment concentration had a significant positive correlation with the maximum consecutive 3-day precipitation. In contrast, average suspended sediment concentration had significant positive correlations with all ratio-based precipitation indices. The existing sediment erosion trend, driven by the amount, intensity, and frequency of extreme precipitation, demands urgency in sediment source management on the Nepal Himalaya’s mountain slopes. The increment in extreme sediment transports partially resulted from anthropogenic interventions, especially landslides triggered by poorly-constructed roads, and the changing nature of extreme precipitation driven by climate variability.

Seasonal horizontal deformations obtained using GPS and GRACE data: case study of North-East India and Nepal Himalaya

The area of North-East India and Nepal Himalaya undergoes seasonal deformations due to the variation of surface mass loads induced mainly by annual monsoon precipitation. The present study focuses on comparing seasonal horizontal deformations of the Earth’s surface obtained over the area of North-East India and Nepal Himalaya using Global Positioning System (GPS) and the corresponding ones obtained from Gravity Recovery and Climate Experiment (GRACE) satellite mission data. Seasonal deformations of the Earth’s surface in horizontal components were determined using daily observations from 36 GPS stations located in North-East India and Nepal Himalaya and Release-05 GRACE-based Global Geopotential Models (GGMs). The consistency between these seasonal horizontal deformations was investigated using three statistical metrics, namely: the correlation, Weighted Root Mean Square (WRMS) reduction and Nash–Sutcliffe model Efficiency (NSE). The results obtained indicate that at nearly 89% of GPS stations investigated, positive correlation can be determined between seasonal deformations of the Earth’s surface in the north component obtained from GPS and the corresponding ones from GRACE data. The percentage of WRMS reductions computed from seasonal horizontal deformations of the Earth’s surface obtained using GPS and GRACE data reach ~ 18% and 0.71% in north and east components, respectively. Moreover, we obtain the median value of NSE almost 0.28 for north and − 0.01 for east components. The study finds that seasonal horizontal deformations in the area investigated are controlled by local tectonics, and realizes the need of a realistic Earth model comprising local crustal inhomogeneities and tectonic features for better constraining the surface deformations in this region.

Morphological diversity within Dendrobium (Orchidaceae) of Nepal

The morphological diversity within Dendrobium Sw., comprising 29 species of Nepal Himalaya, is presented. The paper provides detailed information about the range of diversity in vegetative and reproductive characteristics. An artificial key to the species is provided for their identification. According to the updated classification of Orchidaceae, genera like Epigeneium and Flickingeria of subtribe Dendrobiinae are merged into genus Dendrobium sensu lato. In the present investigation, the morphological diversity within 29 species of Dendrobium viz. D. amoenum, D. amplum, D. anceps, D. aphyllum, D. bicameratum, D. chrysanthum , D. crepidatum, D. darjeelingense, D. denneanum, D. densiflorum, D. denudans, D. eriiflorum, D. fimbriatum var. oculatum, D. formosum, D. fugax, D. fuscescens, D. gibsonii, D. heterocarpum, D. longicornu, D. moniliforme, D. monticola, D. moschatum, D. nobile, D. plicatile, D. polyanthum, D. porphyrochilum, D. rotundatum and D. transparens of Nepal Himalaya were studied.

Morphological and wood anatomical traits of Rhododendron lepidotum Wall ex G. Don along the elevation gradients in Nepal Himalayas

ABSTRACT Though variability in morphological features along the environmental gradients has been extensively studied, less information is available on possible adaptations and trends of anatomical features. We examined the variation in morphological and stem anatomical features of a widely distributed (2,200–5,300 m a.s.l.) Rhododendron lepidotum across elevation gradients in Langtang and Sagarmatha National Parks of Nepal Himalayas. Plant samples in each site were collected from three elevation bands (ca. 3,000, 4,000, and 5,000 m a.s.l.). In both study sites, all morphological features measured had their highest value at the lowest elevation and vice versa. Vessel density of basal stem increased but diameter and area of xylem vessels, and length of vessel element and fiber tracheids decreased as elevation increased. Similarly, height and the number of cells in uniseriate rays and height, width, area, and density of multiseriate rays also decreased toward the highest elevation. However, anatomical features of the ultimate branch did not show any distinct pattern with elevation. Morphological features showed more plasticity than anatomical features along the elevation gradients. Decreased plant height, individual leaf area, specific leaf area, and the existing trade-off relationship between vessel diameter and density could have supported a wide distribution of R. lepidotum in Nepal Himalayas.

FLOOD HAZARD VULNERABILITY MAPPING FOR DARBHANGA DISTRICT OF BIHAR USING SAR DATA: EFFORT TOWARDS EFFECTIVE DISASTER MANAGEMENT

Bihar experiences floods every year due to heavy rainfall in monsoon season and melting of snow in upper reaches of Himalayas during the summers causing both infrastructural damage and loss of life. During the floods, the sky is overcast, due to which traditional techniques of flood mapping and monitoring like aerial surveys and optical sensor satellite imagery fail to provide a good quality data as they are unable to penetrate through clouds and mist. New and alternative technique for the mapping of floods is the use of Synthetic Aperture Radar (SAR) data, which is capable of penetrating through clouds since it uses microwaves to capture the data. For the present study, Darbhanga district of Bihar was taken as the study area. The district faces floods each year due to Kosi River which emerges from Nepal Himalayas and enters Bihar. Aim of the study was to create flood hazard vulnerability map using flood inundation extent maps for the years 2017 to 2020. These maps help in demarcating and identifying the areas which are highly prone to floods annually. Flood inundation extent maps for this study were generated for each year from 2017 to 2020 using Sentinel-1 data and ArcGIS software. These flood inundation extent maps were then superimposed, and a vulnerability map was created. This flood hazard vulnerability map is a valuable source of information while making disaster management plan for the DRR of the region. These maps can help to understand spatial extent of flooding, and can provide scientists and authorities with objective data sources for decision making. These maps can play an important role in pre-disaster and post-disaster strategy planning in an effort towards making the community aware, more resilient and well prepared to face the disaster.

Thematic issue: Evolution of Nepal Himalaya

Thematic issue: Evolution of Nepal Himalaya

Miocene provenance change in Himalayan foreland basin and Bengal Fan sediments, with special reference to detrital garnet chemistry

AbstractBengal Fan Miocene sediments were collected during International Ocean Discovery Program Expedition 354 and investigated using petrographic and detrital garnet chemistry analyses. The Miocene Siwalik Group, which is composed of sediments deposited in the Himalayan foreland basin, was also analyzed for comparison with the Bengal Fan data for the provenance change during the Miocene. Our petrographic analyses revealed that the Miocene sediments of the Bengal Fan and Siwalik Group consist predominantly of Higher Himalayan Crystalline (HHC)‐derived detritus such as chloritoid, staurolite, sillimanite, and/or kyanite, which appear among the accessory minerals. The chemistry of the detrital garnet varies across the stratigraphy; most of the garnet is rich in almandine and poor in spessartine and pyrope. However, pyrope‐rich garnet, which is considered to originate from the HHC core (granulite facies), was found in the lower to upper Miocene deposits. The deposition of HHC‐derived detrital garnet began before the Middle Miocene (15 Ma) and before the Late Miocene (10–9 Ma) in the Siwalik Group. The Bengal Fan data, by contrast, indicated that pyrope‐rich garnet appeared in the Early Miocene (17.3 Ma) and Late Miocene (8.5–6.5 Ma). We conclude that the Bengal Fan sediments record the erosion of the HHC zone since the Early Miocene that appears in the Siwalik sediments. Furthermore, we found that the HHC‐derived inputs decreased from the late Middle Miocene (12 Ma) to the early Middle Miocene (10 Ma) in both the Nepal Himalaya foreland basin and the Bengal Fan. The disappearance of the HHC‐derived detritus is probably the result of dilution by Lesser Himalayan detritus, which suggests that the Lesser Himalayan zone, which is composed of metamorphosed and unmetamorphosed sedimentary rocks, was uplifted.

Chains of influence in Himalayan grammars: Models and interrelations shaping descriptions of Tibeto-Burman languages of Nepal

Abstract This paper examines comparability of descriptive grammars across typologically different languages. Focusing on the Nepal Himalayas, which has high language diversity that extends beyond areal, genetic, and historical categorization, the paper examines similarities across grammars and the influences motivating these. It reports on the construction and use of a database comprising materials from 18 descriptive grammars of Tibeto-Burman languages of Nepal written over a 30-year period. This includes a small sub-database of metadata noting grammarian linguistic training, career affiliations, and dissertation supervisors and a larger sub-database of fully tagged tables of contents for each of the grammars. The overarching relational database links sections containing similar content, enabling search functions to explore the locations of similar information and feature labels across grammars in the database. While some grammar-features in the corpus reflect broader structural properties across grammars, findings indicate strong local influences. We find evidence of three foundational linguistic “schools” connecting the structural organization of the grammars across multiple generations of linguists, correspondences across chapter titles, sections, as well as school-influenced organization of verbal paradigms, treatment of marginal topics, and terminological choices.

Methane emissions respond to soil temperature in convergent patterns but divergent sensitivities across wetlands along altitude.

Among the global coordinated patterns in soil temperature and methane emission from wetlands, a declining trend of optimal soil temperature for methane emissions from low to high latitudes has been witnessed, while the corresponding trend along the altitudinal gradient has not yet been investigated. We therefore selected two natural wetlands located at contrasting climatic zones from foothill and mountainside of Nepal Himalayas, to test: (1) whether the optimal temperature for methane emissions decreases from low to high altitude, and (2) whether there is a difference in temperature sensitivity of methane emissions from those wetlands. We found significant spatial and temporal variation of methane emissions between the two wetlands and seasons. Soil temperature was the dominant driver for seasonal variation in methane emissions from both wetlands, though its effect was perplexed by the level of standing water, aquatic plants, and dissolved organic carbon, particularly in the deep water area. When integrative comparison was conducted by adding the existing data from wetlands of diverse altitudes, and the latitude-for-altitude effect was taken into account, we found the baseline soil temperatures decrease whilst the altitude rises with respect to a rapid increase in methane emission from all wetlands, however, remarkably higher sensitivity of methane emissions to soil temperature (apparent Q10 ) was found in mid-altitude wetland. We provide the first evidence of an apparent decline in optimal temperature for methane emissions with increasing elevation. These findings suggest a convergent pattern of methane emissions with respect to seasonal temperature shifts from wetlands along altitudinal gradient, while a divergent pattern in temperature sensitivities exhibits a single peak in mid-altitude.

Climate Change and Its Possible Impact in Groundwater Resource of the Kankai River Basin, East Nepal Himalaya

Increasing evidence of changing climate patterns is being observed, and the impact of this change on groundwater has a direct impact on the livelihood and economy of the region. The research focuses on the impacts of global temperature increase and changing precipitation on the groundwater resources of part of the Himalayan river system. The spatial and temporal variations of the hydro-meteorological data of the Kankai River Basin in East Nepal were analyzed using non-parametric Mann–Kendall tests and Sen’s Slope methods, whereas CanESM2 was used to predict the future precipitation scenarios, and an attempt has been made to evaluate the possible impacts on groundwater systems in the region. The temperature shows a significant warming trend (0.14–0.64 °C/decade); however, the precipitation trends suggest remarkable variation mostly at higher elevation. The average annual precipitation suggests a decrease of 1.82 mm/year and a similar decrement has been projected for the future. The groundwater in the region has been influenced by the changing climate and the condition may further be exaggerated by reduced recharge and increased evapotranspiration. This understanding of the impacts and climate scenarios will help the planners with better adaptation strategies, plans, and programs for a better society.

Sulfate sulfur isotopes and major ion chemistry reveal that pyrite oxidation counteracts CO2 drawdown from silicate weathering in the Langtang-Trisuli-Narayani River system, Nepal Himalaya

Drawdown of atmospheric carbon dioxide (CO2) due to silicate weathering in the Himalaya has previously been implicated in Cenozoic cooling. However, over timescales shorter than that of the removal of marine sulfate (SO42−), the oxidation of pyrite (FeS2) in weathering systems can counteract the alkalinity flux of silicate weathering and modulate pCO2. Here we present evidence from 34S/32S isotope ratios in dissolved SO42− (δ34SSO4), together with dissolved major ion concentrations, that reveals FeS2 oxidation throughout the Langtang-Trisuli-Narayani River system of the Nepal Himalaya. River water samples were collected monthly to bimonthly throughout 2011 from 16 sites ranging from the Lirung Glacier catchment through the Narayani River floodplain. This sampling transect begins in the High Himalayan Crystalline (HHC) formation and passes through the Lesser Himalayan (LH) formation with upstream influences from the Tethyn Sedimentary Series (TSS). Average δ34SSO4 in the Lirung Glacier outlet is 3.6‰, increases downstream to 6.3‰ near the confluence with the Bhote Kosi, and finally declines to −2.6‰ in the lower elevation sites. Using new measurements of major ion concentrations, inversion shows 62–101% of river SO42− is derived from the oxidation of sulfide minerals and/or organic sulfur, with the former process likely dominant. The fraction of H2SO4-driven weathering is seasonally variable and lower during the monsoon season, attributable to seasonal changes in the relative influence of shallow and deep flow paths with distinct residence times. Inversion results indicate that the primary control on δ34SSO4 is lithologically variable isotope composition, with the expressed δ34S value for the LH and TSS formations (median values −7.0–0.0‰ in 80% of samples) lower than that in the HHC (median values 1.7–6.2‰ in 80% of samples). Overall, our analysis indicates that FeS2 oxidation counteracts much of the alkalinity flux from silicate weathering throughout the Narayani River system such that weathering along the sampled transect exerts minimal impact on pCO2 over timescales >5–10 kyr and <10 Myr. Moreover, reanalysis of prior datasets suggests that our findings are applicable more widely across several of the frontal Himalayan drainages.

A Short Note on Linkage of Climatic Records between Terai and Mid-mountain of Central Nepal

The steep North to South (N-S) gradient and complex topography marks significant variations in the spatial and temporal patterns of climatic variation surrounding within a few distances in the Nepal Himalayas. Hence, to validate climatic linkages between the stations under two distinct topographic conditions, the study examines the observational climatic data from 106m a.s.l. and 1801m a.s.l., as a representative station from a plain and hilly area. Different statistical tools including Pearson correlation analysis and a best-fit regression model were applied to analyze climate data. The analysis of 13129 daily average temperature records and 13147 daily total precipitation records showed that the variation in their sum and average of daily, five days, ten days, and monthly values between the stations in the different elevations marked significantly.Despite these variations, temperature records are measured to be consistent in different altitudes and strongly correlated. The precipitation data showed a comparatively weaker correlation. The coefficients (0.85-1.6) with R2 &gt;0.50 in the regression models for the lower elevation and higher elevation station in the mid-mountain region except for the monsoon season. It indicated a similar fluctuation of temperature between these two stations in the respective area. The strong degree of association and the change of climatic parameters in different range and elevations indicate the possibilities of using climatic data from Terai to represent the Mid-mountain region of central Nepal.

Negotiating professional authority and power in tourist–guide communication in guided village tour

AbstractThe article examines the linguistic, material, and multimodal aspects of professional communication in guided tours in the Himalayas in Nepal. Using an ethnography‐informed interactional sociolinguistics, the study analyses the key instances of miscommunication between an American tourist and an ethnic Tamang guide to understand how various identities are invoked by the participants. As the article considers the complexity of working for tourists in the second language in which a worker's competence is questioned, it also recognizes the importance of a range of semiotic resources that tour guides deploy to negotiate professional authority with tourists. Overall, the findings show how individuals manage interpersonal relations and expertise in transnational workplaces to contest and reconstruct dominant social positions and achieve their interactional goals.