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The Chir-Pine (Pinusroxburghii) and Banj-Oak (Quercus leucotrichophora)-dominated ecosystems of central Himalaya provide significant green services. However, responses of these ecosystems, with respect to ecosystem carbon flux variability, to changing microclimate are not yet studied. Since quantification of ecosystem responses to fluctuation in the microclimate, particularly rainfall, is expected to be beneficial for management of these ecosystems, this study aims (i) to quantify and compare amplitude of rainfall-induced change in the carbon fluxes of Chir-Pine and Banj-Oak-dominated ecosystems using wavelet methods, and (ii) to quantify and compare dissimilarities in the ecosystem exchanges due to varying rainfall spell and amount. Eddy covariance–based continuous daily micrometeorological and flux data, during the 2016–2017 monsoon seasons (total 244 days, 122 days of June–September), from two sites in Uttarakhand, India, are used for this purpose. We find that both Chir-Pine and Banj-Oak-dominated ecosystems are the sinks of carbon, and Chir-Pine-dominated ecosystem sequesters around 1.8 times higher carbon than the Banj-Oak. A systematic enhancement in the carbon assimilation of the Chir-Pine-dominated ecosystem is noted with increasing rainfall spell following a statistically significant power-law relationship. We have also identified a rainfall amount threshold for Chir-Pine and Banj-Oak-dominated ecosystems (10 ± 0.7 and 17 ± 1.2 mm, respectively) that resulted in highest ecosystem carbon assimilation in monsoon. The general inference of this study accentuates that Banj-Oak-dominated ecosystem is more sensitive to maximum rain within a spell whereas the Chir-Pine-dominated ecosystem is more responsive to increasing rainfall spell duration. [ABSTRACT FROM AUTHOR]

Year-round flow consistencies of the central Himalayan springs are extremely important for addressing rural water demand. As the prediction of Himalayan spring high-flows is expected to provide better opportunities for the management of excess runoff, this study aims to develop a data-driven model for predicting joint-fracture and depression type spring high-flows of the Kosi watershed of central Himalaya, India. Five machine learning algorithms are used with combinations of predictors, such as standardized anomaly of rainfall, pH, electrical conductivity and water quality index of spring water. The discharge and predictor parameters are used from a total of 06 springs distributed across the watershed, and monitored during January, 2019 to December, 2020 at monthly interval. Due to asymmetric relationships between model predictors and spring discharge, model performances are tested for the predictor time lags of 0–2 (= 60 days). A total of ten experiments are carried out, and model performances during training and testing are evaluated using receiver operator characteristics. The discriminant analysis classifier, in combination with rainfall and electrical conductivity as predictors, is found to be the best model for predicting spring high-flows. [ABSTRACT FROM AUTHOR]

Characteristics of the winter-season vertical structures of stratiform rainfall over central Himalaya are investigated using a vertically pointing Micro Rain Radar (MRR) at GBPNIHE, Kosi-Katarmal, Almora (29.59 ∘ N, 79.65 ∘ E), India. Rainfall micro-structures, such as reflectivity (Z), rain rate (R), liquid water content (LWC) and average fall speed of the drops ( v m ) upto 6000 m above ground are monitored during 01 November, 2020 to 28 February, 2021. The MRR observations are used to (1) identify bright band signatures, and develop linear parameterizations between maximum radar reflectivity and radar reflectivities of snow and rain layers, (2) quantify changes in the vertical profiles of Z, R, LWC and v m , (3) evaluate near surface rainfall drop size distribution and its linkages to drop diameter, and (4) investigate vertical profiles of Z–R relationships using Marshall–Palmer distribution, during stratiform rain. We find that 25.4% of all the observed rainfall events is associated with bright band signatures, where bright bands are observed at an average 2536.5 (± 422.1) m height above the ground associated with mean maximum reflectivity of 20.8 (± 2.37) dBZ. Almost linear relationships amongst maximum reflectivity and reflectivities of snow and rain layers during bright band signatures are observed. The near-surface raindrop size distributions of this study indicate mean drop concentrations during January and February months are 3.78 (± 0.09) m 3 mm - 1 , whereas the same during December is 3.45 (± 0.17) m 3 mm - 1 . Highest drop diameter of 4.94 mm is obtained during rain events of January and February, 2021, due to higher coalescence of drops. Coefficients a and b of the power–law relationships between Z–R varied between 246.0 and 367.5 and 1.61 and 2.45, respectively, within the reported range of stratiform rain in India. [ABSTRACT FROM AUTHOR]

The net carbon uptake of the natural and dense Himalayan ecosystems is not well explored at a sub-daily scale due to limited data availability. Here, we present the first-ever analysis of the hydrometeorological controls of the sub-daily scale Net Ecosystem Exchange (NEE) in a Western Himalayan pine-dominated ecosystem ( Pinus roxburghii ). We used observed half-hourly flux tower data for 104 weeks from December 2014 to November 2016. We found that the sub-daily (6 h) scale variability of NEE contributes 20–40% to its within-week variability. We generated transfer entropy (TE)-based weekly process networks with a maximum memory of 6 h to understand sub-daily scale processes. Using weekly networks, we present consistent causal links on a seasonal scale. The hydrometeorological variables affecting the NEE and Ecosystem Respiration (RE) at a sub-daily scale are Net Solar Radiation (NSR), Relative Humidity (RH), Surface Air Temperature (TA), and Sensible Heat Flux (SH). These variables are consistently active in the networks with seasonally varying magnitudes of TE. We also found that for both monsoon and post-monsoon, NEE receives more incoming links from meteorological variables during dry weeks than wet weeks. Precipitation (P) did not send a direct causal link to NEE or RE within a sub-daily scale but strongly influenced the causal associations between hydrometeorological and carbon exchange variables. The network does not show any immediate (within 6 h) impact of P on NEE, which probably implies a delayed response of vegetation to P through soil moisture. At higher memory, P may act as an influential background variable. • Hydrometeorological controls on NEE of the Himalayan Pine ecosystem are identified. • Transfer entropy-based causal network approach is adopted. • Sub-daily to intra-weekly variation ratio of NEE is noted to be 20–40%. • Precipitation doesn't send a direct causal link to NEE within a 6-h time scale. • NEE receives more casual links from meteorological variables in dry weeks. [ABSTRACT FROM AUTHOR]

The present study is an attempt to analyse the precipitable water vapour (PWV) derived from Global Positioning System (GPS) and observed meteorological data over Almora, Central Himalayan Region. The PWV values derived using GPS study is compared with the corresponding moderate resolution imaging spectro-radiometer (MODIS) data. The statistical analysis reveals a positive correlation between both methods. Moderate resolution imaging spectroradiometer near-infrared (MODIS NIR) clear column water vapour product shows a higher correlation ( R = 90-93 %) with GPS-derived precipitable water vapour on annual scale as compared to the seasonal scale ( R = 62-87 %). MODIS is found to be overestimating in NIR clear column where the magnitude of bias and RMSE show systematic changes from season to season. Monsoon is an important phenomenon in the Indian weather context and holds significant importance in Central Himalayan ecosystem. The monthly and seasonal variation in precipitable water vapour is related with monsoon onset in the region. Diurnal variations in precipitable water vapour are studied with other meteorological data over Almora during dry and wet season. The precipitable water vapour had minimum value in the morning, increases in the afternoon to evening and again decreases to the midnight in both the dry and wet seasons. These results suggest that diurnal variation of water vapour is caused by the transport of water vapour by thermally induced local circulation. [ABSTRACT FROM AUTHOR]

Deformation rates derived from GPS measurements made at two continuously operating stations at Leh (34.1°N, 77.6°E) and Hanle (32.7°N, 78.9°E), and eight campaign sites in the trans-Himalayan Ladakh spanning 11 years (1997-2008), provide a clear picture of the kinematics of this region as well as the convergence rate across northwestern Himalaya. All the Ladakh sites move 32-34 mm/year NE in the ITRF2005 reference frame, and their relative velocities are 13-16 mm/year SW in the Indian reference frame and ~19 mm/year W with reference to the Lhasa IGS station in southeastern Tibet. The results indicate that there is no statistically significant deformation in the 200-km stretch between the continuous sites Leh and Hanle as well as between Leh and Nubra valley sites along the Karakoram fault, whereas the sites in and around the splayed Karakoram fault region indicate surface deformation of 2.5 mm/year. Campaign sites along the Karakoram fault zone indicate a fault parallel surface motion of 1.4-2.5 mm/year in the Tangste and western Panamik segment of the Karakoram fault, which quantifies the best possible GPS-derived dextral slip rate of 3 mm/year along this fault during this 11-year period. Baselines of Ladakh sites show convergence rates of 15-18 mm/year with respect to south India and 12-15 mm/year with respect to Delhi in north India and Almora in the Himalaya ~400 km north-northeast of Delhi. These constitute an arc normal convergence of 12-15 mm/year across the western Himalaya, which is consistent with arc normal convergence all along the Himalayan arc from west to east. Baseline extension rates of 14-16 mm/year between Lhasa and Ladakh sites are consistent with the east-west extension rate of Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The present study elucidates velocity of the Indian plate from 2013 to 2016 with the help of six continuously operating permanent Global Positioning System (GPS) stations and tracks the crustal motion and direction directly by means of space-based geodetic measurements. The GPS derived velocity estimates were computed with respect to 2008 International Terrestrial Reference Frame (ITRF 08) and carried out almost all along the arc in the Indian Himalayan Region (IHR). The velocity vectors indicate that the Indian plate is moving towards the NE direction (average velocity of 46.95 ± 0.23 mm/yr) with higher movement towards the eastward direction (36.11 ± 0.17 mm/yr) compared to the northward direction (29.02 ± 0.16 mm/yr). Variations in the plate motion between IISC and permanent GPS stations suggest that presently, the convergence rate is about 8.06 ± 0.28 mm/yr and 5.71 ± 0.17 mm/yr for Higher Himalaya and Lesser Himalaya respectively. In addition, the deformation rate was also calculated on the basis of baseline shortening between IGS stations (IISC and LHAZ) and permanent GPS stations. The results suggest that the deformation is about 11.68 ± 1.32 mm/yr above the Main Central Thrust (MCT) and 6.74 ± 1.20 mm/yr above the Main Boundary Thrust (MBT) with respect to the Indian plate (IISC), while it is 20.60 ± 1.76 mm/yr above the MCT and 11.42 ± 1.21 mm/yr above the MBT with respect to Eurasian plate (LHAZ). The strain rate through GPS measurement reveals that the maximum strain is accumulated in the central part of the Himalaya between the MBT and MCT, indicating vulnerability of the central Indian Himalaya for future earthquakes. [ABSTRACT FROM AUTHOR]

The article discusses the Indian Himalayan Region's (IHR) water source and security from springs and its spring-ecosystem and management as of October 2021. Topics covered include the spring dry up issue that has led to migration of people and disturbance of social and cultural relevance in the IHR, and the transformative programme to boost knowledge on biotic and abiotic interaction in the IHR spring-ecosystem. Also noted are recommendations made in the programme meeting.

Both in-situ and space-borne observations reveal an extremely high loading of particulates over the Indo-Gangetic Plains (IGP), all year around. With a burgeoning population and combustion sources (fossil fuels (FFs) and biofuels (BFs)) in close proximity to each other, the IGP is widely regarded as a hotspot for anthropogenic aerosol emission in South Asia. The deteriorating air quality over this region, particularly during winters, is a cause of major concern, since the pollutants undergo long range transport from their source regions to the Indo-Himalayan Range (IHR), Bay of Bengal (BoB) and other remote areas, polluting their pristine atmospheric conditions. Seasonal reversal in winds over the Indian mainland leads to an outflow of continental pollutants into the BoB during winters and a net advection of desert dust aerosols into the IGP from southwest Asia (SW-Asia), northwest India (NW-India) and northern Africa (N-Africa) during summers. Through the course of this study, four observational campaigns were conducted for sampling the ambient PM 2.5 and PM 10 during winter and summer seasons of 2014–2015, at multiple locations (18 sites) in the IGP, IHR, and semi-arid/arid sites towards their south and west, in order to accurately determine the inter-seasonal and inter-annual changes in the aerosol loading at the sites. We have also utilized data from Moderate Resolution Imaging Spectroradiometer (MODIS) on-board Earth Observing System (EOS) Terra satellite for estimating the columnar Aerosol Optical Depth at 550 nm (AOD 550 ) and data from EOS Terra and Aqua satellites for discovering openly burning fires in the vicinity of sampling sites. Determination of the major source regions and key transport pathways during both seasons have also been attempted, using back-trajectory cluster analyses, as well as receptor models such as PSCF and CWT. [ABSTRACT FROM AUTHOR]

Springs and streams are essential sources of fresh water for the Himalayan population. To global and regional extents, these resources are being severely affected by climate change as well as anthropogenic activities. However, the effects of seismicity also have considerable influence on springs but are negligibly studied in that aspect. Crustal deformation, shaking, and movement of the earth's surface due to an earthquake, can modify the stream flow and water level in wells through consolidation of surficial deposits and development of new fractures. The present study addresses the effect of an earthquake on water springs in a seismically active zone. On 18 September 2011, the Sikkim Himalaya experienced a strong earthquake of magnitude (Mw) 6.9. To assess the impact of this earthquake on hydrology, we studied the springs located in the South Sikkim district, India. Our research indicates that few springs dried up following the Mw 6.9 earthquake in 2011 while some springs discharged at a higher rate than before. The springs which were dried up due to climate change were excluded in this study. Furthermore, our study suggests that in tectonically active mountain ranges, like Himalaya, an earthquake not only causes surficial deformations but also influences the hydrological framework at a regional scale. Therefore, the seismic nature of the terrain should also be considered for spring rejuvenation policies. • Impact of an earthquake on water bodies were studied. • Himalayan springs are sensitive to both climate change as well as earthquakes also. • An earthquake having magnitude Mw ≥ 5 may affect the discharge of a spring. [ABSTRACT FROM AUTHOR]

The Himalayan mountain system to the north of the Indian land mass with arcuate strike of NW-SE for about 2400 km holds one of the largest concentration of glaciers outside the polar regions in its high-altitude regions. Perennial snow and ice-melt from these frozen reservoirs is used in catchments and alluvial plains of the three major Himalayan river systems, i.e. the Indus, Ganga and Brahmaputra for irrigation, hydropower generation, production of bio-resources and fulfilling the domestic water demand. Also, variations in the extent of these glaciers are understood to be a sensitive indicator of climatic variations of the earth system and might have implications on the availability of water resources in the river systems. Therefore, mapping and monitoring of these freshwater resources is required for the planning of water resources and understanding the impact of climatic variations. Thus a study has been carried out to find the change in the extent of Himalayan glaciers during the last decade using IRS LISS III images of 2000/01/ 02 and 2010/11. Two thousand and eighteen glaciers representing climatically diverse terrains in the Himalaya were mapped and monitored. It includes glaciers of Karakoram, Himachal, Zanskar, Uttarakhand, Nepal and Sikkim regions. Among these, 1752 glaciers (86.8%) were observed having stable fronts (no change in the snout position and area of ablation zone), 248 (12.3%) exhibited retreat and 18 (0.9%) of them exhibited advancement of snout. The net loss in 10,250.68 sq. km area of the 2018 glaciers put together was found to be 20.94 sq. km or 0.2% (± 2.5% of 20.94 sq. km). [ABSTRACT FROM AUTHOR]

The article discusses the necessity of strengthening mountain-specific research. It states that the Himalaya holds a special position with vast, complex and highly variable in space and time, making difficult to understand and characterize with the best scientific efforts. Information on workshop which mainly targeted stock of the present state of research, and associated gaps and discrepancies, is offered.

The article discuss the need of strategic environmental assessment of hydropower projects in India, to meet the demand and supply of energy. It mentions needs of harnessing hydropower projects in Indian Himalayan Region for maximum economic development. It discusses strategic plan for the future development of hydropower projects.