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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]

This paper presents an insight on major ion chemistry and identification of solute sources in meltwater of Chaturangi glacier throughout the ablation period 2015 and 2016. The results indicate that meltwater is slightly acidic with Ca–HCO3 and Mg–HCO3 dominated hydrochemical facies. In meltwater, Ca2+ and HCO3− are the most dominant cation and anion, respectively. The Water Quality Index values show that the quality of meltwater is good for both the ablation seasons. An important factor governing the quality of water is the residence time for dissolving minerals from the rocks. Mineralogy of surrounding rocks and Gibbs plot suggest that the meltwater ionic concentration is mostly controlled by weathering of rocks with slight contribution from atmospheric aerosols. For meltwater, the average equivalent ratios of Na/Cl and K/Cl were calculated as 3.36 ± 1.29 and 2.29 ± 0.62 in 2015 and 1.39 ± 0.6 and 0.8 ± 0.2 in 2016, which are considerably higher than the marine aerosols (Na/Cl = 0.85 and K/Cl = 0.017), it also confirmed the less contribution of atmospheric input in meltwater. The petrographic analysis of surrounding rocks indicate positive relationship among the cations (Ca2+, Mg2+, Na+ and K+) and mineral abundance. Our observations suggest that the bedrock mineralogy and weathering reactions together with amount and composition of atmospheric inputs are the main sources of ions, dissolved in the glacier meltwater. It might be due to rate of chemical reaction which leads decomposition of rocks and leaching of minerals into the meltwater. Additionally, the geology of the area plays a significant as the influence of geology and climate on water quality is observed by the quantity and types of dissolved materials and amount of the sediment carried by the streams. The elevated proportion of Ca + Mg in total cations and high Ca + Mg/(Na + K ratios, 1.47 ± 0.14 in the year 2015 and 1.44 ± 0.28 in 2016 clearly reveal that the ionic composition is primarily controlled by carbonate weathering and partly by silicate weathering. Further, the low Na + K/TZ− ratio (0.41 ± 0.02) and (0.22 ± 0.05) in 2015 and 2016, respectively also supports that carbonate weathering is main geochemical process controlling the hydrochemistry of meltwater. In addition, the ion denudation rate was calculated for both the years. The results show that the cation denudation rate of meltwater was 32.84 and 22.30 ton/km2/ablation during 2015 and 2016, respectively, whereas the anion denudation rate was found to be 205.43 in 2015 and 170.24 ton/km2/ablation in 2016. [ABSTRACT FROM AUTHOR]

Monitoring and mapping physicochemical properties of springs water are very crucial in Upper Kosi watershed as natural springs, and spring-fed streams are the only source of drinking water for thousands of inhabitants living there. Understanding of hydro-geochemical characteristics and water quality of the springs in perched aquifers of the basin provides useful information for sustainable use of spring's water with climate change scenarios. For this purpose, a total of 65 springs were inspected and investigated for their significant particle scenario to evaluate their water quality, potential origins, and hydro-chemical evolution. Groundwater samples were collected from springs under consideration and are examined for an aggregate of 14 water quality physicochemical parameters during pre- and post-monsoon season. Two types of hydro-chemical complexions were observed during pre-monsoon sample analysis. One is Ca–Mg–HCO3−, and the other is a mixed Ca–Mg–Cl−paradigm. It perceived that hydro-chemical facies Ca–Mg–Cl− was shifted into Ca–Mg–HCO3− in post-monsoon. Higher deviation in turbidity, magnesium, and sulphate indicated that geochemistry of the study area is not homogenous. A significant degree of seasonal variations in the concentration water quality parameters like pH, Cl−, F−, SO42− K+, total alkalinity, and bicarbonate was analysed using one way ANOVA (p ≤ 0.05). As per concern of quality, groundwater emanating from these springs is apposite for drinking as per drinking water specifications provided by the Bureau of Indian Standards (IS 10500:2012). [ABSTRACT FROM AUTHOR]

There are two models for the surface layer in the convective boundary layer (CBL). First is the standard Monin–Obukhov similarity theory, and second is the McNaughton–Laubach model (Laubach and McNaughton 2009, Boundary-Layer Meteorology 133:219–252; hereafter MNL model) developed based on the complex dynamical system approach to address characteristics of the unstable surface layer. The fundamental difference between the Monin–Obukhov similarity theory and the MNL model is the use of local and non-local parameters for analyzing surface-layer spectra in the CBL. However, there is a need to check applicability of this new model at various flow conditions before the model could be extensively used. Subsequently, applicability of the MNL model is tested in comparison to the standard model using CBL observations from three different regions with increasing terrain complexity (i.e. over flat-terrain, onslope, and ridge-top sites). The MNL model is tested by estimating and using the non-local scaling parameters to collapse the power spectra of velocity and temperature on the frequency–amplitude scale under the generalized hypothesis that convective surface layer depends on non-local outer variables. We find that the u and v spectra for all sites indicate run-to-run similarity of each spectra with MNL scaling irrespective of the height limiting role of local buoyancy on the shape of the spectra. Similarly, w spectra from all sites indicate transitions between the surface friction layer and the outer layer are governed by flow in the entire CBL. The temperature spectra collapse using (z ϵ o) 2 / 3 H 0 - 2 as amplitude scaling and k z i 1 / 2 z 1 / 2 as wavenumber scaling, is a new observation within the surface friction layer, where the streamwise wavenumber is k, measurement height is z, CBL height is z i , the dissipation rate of turbulence energy in the outer CBL is ϵ o , and the surface heat flux is H 0 . These observations corroborate well with the MNL model conjecture that the convective temperature spectra do not depend only on local stability, and CBL parameters affect spectra when a subset of local factors remains constant. [ABSTRACT FROM AUTHOR]

Snout monitoring of the Gangotri glacier (Uttarakhand, India) during the ablation season (May to September) in years 2005 and 2015 by using rapid static and kinematic GPS survey reveals that the retreating rate has been comparatively more declined than shown by the earlier studies. Our study is based on the individual measurement by the remote sensing, added by the ground observations by using Differential global positioning system (DGPS) to determine the precise recession rate of the glacier at sub-centimeter level of accuracy. The GPS dataset show that the total average retreat along the snout has been 102.57 ± 0.05 m from 2005 to 2015 with an average rate as 10.26 ± 0.05 m/yr. Additionally, the shift in snout position was also measured through multi-temporal satellite data from 1989 to 2016. The results indicate that the Gangotri glacier snout has retreated by 585.62 ± 38.30 m during this period with an average retreat of 26.75 ± 4.36 m/yr from 1989 to 1999, 21.58 ± 3.77 m/yr from 1999 to 2009 and 14.60 ± 4.81 m/yr from 2009 to 2016. Such a decline in retreat is further confirmed by the satellite data set. A close examination of meltwater discharge and retreating rate (r2 = 0.95) show that both parameters are strongly correlated. Therefore, we suggest that a consistent decrease in meltwater discharge from 1999 to 2015 is in agreement with decreasing trend of retreating rate during the recent years. To determine the possible causes of decreased retreating rate, a relationship between debris thickness and melt rate was also established by ablation stakes. Further, we infer that the declining trend in the glacier retreat is not only controlled by prevailing weather conditions (rainfall and air temperature) but is also governed by increased debris cover on the glacier surface which prevents the ice to melt. [ABSTRACT FROM AUTHOR]

In this study, we present analysis of stream flow near the snout of Chaturangi glacier during the ablation season (June to September (JJAS)) in the year 2015 with an aim to estimate the sediment and water input into the Bhagirathi River from the glacier. In order to assess the variation in meltwater discharge from Chaturangi glacier and to determine its relationship with suspended sediment concentration (SSC), the meltwater and discharge data were analyzed from near the snout to avoid mixing of water and sediment from other glacier tributaries. The meltwater discharge was measured by area velocity method, and the SSC was calculated by vacuum filtration technique. During the entire ablation season (JJAS), marked seasonal variations were observed in the SSC and meltwater discharge. The higher variation is observed in suspended sediment load (SSL) (Cv = 1.17) than SSC (Cv = 0.54) because computation of SSL includes both discharge (Cv = 0.76) and SSC. The average monthly SSC for JJAS was found to be 0.99, 2.29, 4.20, and 1.84 g l−1, respectively, and average monthly meltwater discharge for same period was observed as 5.83, 14.48, 39.81, and 12.69 m3 s−1, respectively. It suggested that throughout the ablation season, the cumulative percentage delivery of SSC follows meltwater discharge. The average suspended sediment yield (SSY) for the entire ablation season was estimated to be 2264.03 ton/km2, and consequent catchment denudation rate was measured as 0.85 mm. A strong positive correlation (r2 = 0.88), found between the discharge and SSC, revealed that both the parameters are dependent on each other. Our results also suggest that the Chaturangi glacier is a major contributor for transportation of sediment into the Bhagirathi River, compared with other tributaries of the Gangotri glacier system. [ABSTRACT FROM AUTHOR]

Uttarakhand, one of the Himalayan foot-hill states of India, covers an area of 51,125 km2. This region is enriched with bio-diversity and is one of the highly potential regions in the Central Himalayas for agro-climate, hydro power generation, food-processing, tourism, etc. Present study investigates the spatio-temporal rainfall distribution over the state during Indian summer monsoon period. Observational and modelled (under different Representative Concentration Pathways (RCPs) at radiative forcing 2.6, 4.5 and 8.5 W/m2) rainfall distribution is studied to assess the present and future trends. Study uses standard observational rainfall estimates from APHRODITE, Tropical Rainfall Measuring Mission (TRMM 3B42) and India Meteorological Department (IMD) gridded rainfall datasets and inter-compare these products in order to find out orographic responses during the monsoon months and elevation dependent mean rainfall pattern changes. It is found that rainfall pattern breaks near 3100 m elevation. Comparative analysis reflects that with respect to IMD, TRMM 3B42 rainfall underestimates more than 3 mm/day rainfall whereas, APHRODITE overestimates rainfall below 4.5 mm/day. Future trends in modelled monsoon rainfall are examined and mixed results are found and discussed with possible explanation. [ABSTRACT FROM AUTHOR]

Hydropower if scientifically developed is considered to be one of the clean and non-polluted renewable energy sources. But its impacts always exist on physical and social environment of the area. The present study was conducted in the River Satluj basin which is well known for its hydropower potential. The main objective of the study was to understand the vulnerability of the Satluj basin and to develop a strategy for the development of hydropower projects. This basin has been facing many problems relating to construction of haphazard development of hydropower projects. This has led multi-hazards like landslides, floods, earthquakes, etc. Here, vulnerability assessment index was assessed quantitatively and qualitatively. Geographical Information System and peoples' perception were used to study these aspects in the basin. The parameters considered for vulnerability assessment were slope, slope profile, relative relief, curvature, slope aspect, soil texture, lithology, river morphometry, precipitation, hydroelectric projects, land use and land cover, mass-movement, flood, geological elements and earthquake occurrences. The highest vulnerability was found in the middle zone, and finally on the basis of parameters analyzed; the hydropower's development strategy was developed. [ABSTRACT FROM AUTHOR]

In view of a significant lacuna in the Himalaya-specific knowledge of forthcoming expected changes in the rainfall climatology, this study attempts to assess the expected changes in the Indian summer monsoon rainfall (ISMR) pattern exclusively over the Indian Himalayan Region (IHR) during 2020-2070 in comparison to a baseline period of 1970-2005 under two different warming scenarios, i.e., representative concentration pathways 4.5 and 8.5 (RCP 4.5 and RCP 8.5). Five climate model products from the Commonwealth Scientific and Industrial Research Organization initiated Coordinated Regional Climate Downscaling Experiment of World Climate Research Programme over south Asia region are used for this purpose. Among the several different features of ISMR, this study attempts to investigate expected changes in the average summer monsoon rainfall and percent monthly rainfall to the total monsoon seasonal rainfall using multimodel averages. Furthermore, this study attempts to identify the topographical ranges which are expected to be mostly affected by the changing average monsoon seasonal rainfall over IHR. Results from the multimodel average analysis indicate that the rainfall climatology is expected to increase by >0.75 mm/day over the foothills of northwest Himalaya during 2020-2070, whereas the rainfall climatology is expected to decrease for the flood plains of Brahmaputra under a warmer climate. The monthly percent rainfall of June is expected to rise by more than 1% over the northwestern Himalaya during 2020-2040 (although insignificant at p value <0.05), whereas the same for August and September is expected to decrease over the eastern Himalaya under a warmer climate. In terms of rainfall changes along the altitudinal gradient, this study indicates that the two significant rainfall regions, one at around 900 m and the other around 2000 m of the northwestern Himalaya are expected to see positive changes (>1%) in rainfall climatology during 2020-2070, whereas regions more than 1500 m in eastern Himalaya are expected to experience inconsistent variation in rainfall climatology under a warmer climate scenario. [ABSTRACT FROM AUTHOR]

This study investigates the altitudinal variation of dominant modes of summer monsoon intra-seasonal oscillation (ISO) over the Northwest (NWH) and Eastern Himalayan (EH) region using (i) spatially scattered 133 number of station rainfall observations and (ii) latitudinal transect-wise (LT) rainfall variation, obtained from an observed interpolated gridded rainfall data for the period 1995-2004. The altitudinal variation of dominant modes of monsoon ISO were investigated by exploring the strong and weak phases of the principal components of 10-90 days bandpass rainfall data of June to September with respect to location specific station height. Investigation of frequency of days for light and moderate rainfall along with the occurrence of total seasonal rainy days has revealed existence of a rainfall maximum around 2100 m height for the NWH region. Similarly, the total seasonal rainy days of EH region was found to have maxima between 1100 and 1400 m height. Analyses of the spatially scattered station rainfall observation for the NWH region showed that the strong periods of ISO modes exist around 747.9 (±131.7) m and 2227.2 (±100.2) m heights. Over the EH region, the dominant modes of the monsoon ISO were found to be centred around 1200 m. Significant alterations of strong and weak phases of monsoon ISO as a response to altitudinal variation in the mountain surface were observed when latitudinal transect-wise variation of monsoon ISO modes were investigated. [ABSTRACT FROM AUTHOR]

Impacts of the changing climatic regime on the trends of Indian summer monsoon rainfall (ISMR) are explored in this study for the Indian Himalayan region (IHR). The analysis is carried out for the period of 1951-2007 using a daily high resolution gridded data from APHRODITE project. At first, the percent departures of decadal rainfall are estimated from the long-term June to September rainfall values for the western, central, and eastern Himalayan (WH, CH, and EH) regions. Next, changes in the frequency of strong and weak phases of monsoon intra-seasonal oscillation are investigated. A non-parametric statistical method (Sen's slope estimator) is applied to the seasonal (i) mean rainfall, (ii) maximum rainfall, and (iii) frequency of extreme rainfall events of WH, CH, and EH regions to identify changes in their decadal, multiple year normals (NY1; 1951-1980 and NY2; 1981-2007) and long-term (NY3; 1951-2007) trends. The inter annual to inter decadal variabilities of the frequency of extreme rainfall events are explored by analyzing statistically significant intrinsic mode functions of the empirical mode decomposition (EMD) method. Results of our analyses have revealed existence of an alternative decadal oscillation of scanty and excessive summer monsoon rainfall trends for the WH, whereas excessive rainfall is observed in the last three decades (1980-2007) over the CH region. It is also observed that the frequencies of both monsoon strong and weak phases are decreasing for the entire Himalayan region. No significant trend is observed for the WH and CH regions for the normal periods NY1, NY2, and NY3 when seasonal average rainfall is considered. However, a significant ( p value < 0.05) negative trend of −0.04 mm/day rain is observed for the EH region during NY1 period. Similarly, the seasonal maximum rainfall trends for all the normal periods are found to be negative of which trends of −0.12 and −0.43 mm/day during NY3 and NY1 are observed for WH and EH regions, respectively ( p value < 0.05). No significant enhancement in the extreme rainfall event frequencies is observed for the entire IHR during 1951-2007. However, a statistically insignificant positive trend in the extreme event frequencies is observed for the EH region. A dominant cycle of ∼ 2.7 years of high frequency of extreme rainfall events is observed for all the regions whereas, a 12.2-, 15.3-, and 5.8-year cycles are observed for the WH, CH, and EH regions, respectively. [ABSTRACT FROM AUTHOR]

The analysis of rainfall pattern and indices of extreme rainfall events is performed for two meteorological stations located in the Central Himalayan Region which is highly vulnerable to rain-induced hazards. The records of these rain-induced disasters suggest that such events are generally observed in later part of monsoon season, when soil is saturated after monsoon rains. An attempt is made here to test trends of 19 different extreme rainfall indices that have been widely used in the literature, using daily rainfall data for two urban centres (Nainital and Almora) over the period 1992-2005. We have used statistical tools such as Sen's method and Mann-Kendall test for detection of trend in annual rainfall, monsoon rainfall, number of rainy days and 1-day extreme rainfall. Principal component analysis gives the correlation between different extreme rainfall indices. Time series of principal components are representing the trends of extreme indices, their variation and interrelation between different indices. The perception study conducted in the same sites indicates that extreme rainfall events and change in rainfall amount and timing are well perceived by the local people. [ABSTRACT FROM AUTHOR]

We present new insights on the time-averaged surface velocities, convergence and extension rates along arc-normal transects in Kumaon, Garhwal and Kashmir-Himachal regions in the Indian Himalaya from 13 years of high-precision Global Positioning System (GPS) time series (1995-2008) derived from GPS data at 14 GPS permanent and 42 campaign stations between $$29.5{-}35^{\circ }\hbox {N}$$ and $$76{-}81^{\circ }\hbox {E}$$ . The GPS surface horizontal velocities vary significantly from the Higher to Lesser Himalaya and are of the order of 30 to 48 mm/year NE in ITRF 2005 reference frame, and 17 to 2 mm/year SW in an India fixed reference frame indicating that this region is accommodating less than 2 cm/year of the India-Eurasia plate motion ( $${\sim }4~\hbox {cm/year}$$ ). The total arc-normal shortening varies between $${\sim }10{-}14~\hbox {mm/year}$$ along the different transects of the northwest Himalayan wedge, between the Indo-Tsangpo suture to the north and the Indo-Gangetic foreland to the south indicating high strain accumulation in the Himalayan wedge. This convergence is being accommodated differentially along the arc-normal transects; $${\sim } 5{-}10~\hbox {mm/year}$$ in Lesser Himalaya and 3-4 mm/year in Higher Himalaya south of South Tibetan Detachment. Most of the convergence in the Lesser Himalaya of Garhwal and Kumaon is being accommodated just south of the Main Central Thrust fault trace, indicating high strain accumulation in this region which is also consistent with the high seismic activity in this region. In addition, for the first time an arc-normal extension of $${\sim }6~\hbox {mm/year}$$ has also been observed in the Tethyan Himalaya of Kumaon. Inverse modeling of GPS-derived surface deformation rates in Garhwal and Kumaon Himalaya using a single dislocation indicate that the Main Himalayan Thrust is locked from the surface to a depth of $${\sim }15{-}20~\hbox {km}$$ over a width of 110 km with associated slip rate of $${\sim }16{-}18~\hbox {mm/year}$$ . These results indicate that the arc-normal rates in the Northwest Himalaya have a complex deformation pattern involving both convergence and extension, and rigorous seismo-tectonic models in the Himalaya are necessary to account for this pattern. In addition, the results also gave an estimate of co-seismic and post-seismic motion associated with the 1999 Chamoli earthquake, which is modeled to derive the slip and geometry of the rupture plane. [ABSTRACT FROM AUTHOR]

The foremost Global Positioning System (GPS) derived measurements in the Kumaun Himalaya indicate that most of the crustal motion of the Indian plate is accommodating towards the base as well as on the hanging wall of Main Central Thrust (MCT). Deformation pattern within the Kumaun Himalaya varies from south to north and indicates maximum deformation rate near MCT. Our study, based on the campaign mode GPS survey during 2003-2006, reveals that the area between north of North Almora Thrust (NAT) and at the base of Great Himalaya registers maximum strain rate, which is lowered towards the Trans Himadri Fault (THF). The GAMIT-GLOBK processed campaign data of the area show that currently, the Himalayan Frontal Fault (HFF) and Main Boundary Thrust (MBT) are locked with the Indian plate, and a 6.7 ± 2.5 mm/yr of horizontal shortening is taking place between the Lesser Himalaya and Peninsular India. [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 investigates solute dynamics of meltwater of Gangotri glacier system in terms of association of different chemical compounds with the geology of the area. In the meltwater, the presence of cations varied as c(Mg2+) > c(Ca2+) > c(Na+) > c(K+), while order of concentration of anions has been c(HCO3 −) > c(SO4 2−) > c(Cl−) > c(NO3 −) in years 2003 and 2004. The magnesium and calcium are found as the dominant cations along with bicarbonate and sulphate as dominant anions. The high ratios of c(Ca2+ + Mg2+)/total cations and c(Ca2+ + Mg2+)/c(Na+ + K+) indicate that the meltwater chemistry of the Gangotri glacier system catchment is mostly controlled by carbonate weathering. Attempts are made to develop rating curves for discharge and different cations. Sporadic rise in discharge without corresponding rise in concentration of most of cations is responsible for their loose correlation in a compound valley glacier like Gangotri glacier. [ABSTRACT FROM AUTHOR]

A study was carried out to discover trends in the rainfall and temperature pattern of the Alaknanda catchment in the Central Himalaya. Data on the annual rainfall, monsoon rainfall for the last decade, and average annual temperatures over the last few decades were analyzed. Nonparametric methods (Mann-Kendall and Sen's method) were employed to identify trends. The Mann-Kendall test shows a decline in rainfall and rise in temperature, and these trends were found to be statistically significant at the 95% confidence level for both transects. Sen's method also confirms this trend. This aspect has to be considered seriously for the simple reason that if the same trend continues in the future, more chances of drought are expected. The impact of climate change has been well perceived by the people of the catchment, and a coping mechanism has been developed at the local level. [ABSTRACT FROM AUTHOR]

Entire Himalayan region is vulnerable to rain-induced (torrential rainfall) hazards in the form of flash flood, cloudburst or glacial lake outburst flood. Flash floods and cloudburst are generally caused by high intensity rainfall followed by debris flow or landslide often resulting into blockade of river channels. The examples of some major disasters caused by torrential rainfall events in last fifty years are the flash floods of 1968 in Teesta valley, in 1993 and 2000 in Sutlej valley, in 1978 in Bhagirathi and in 1970 in Alaknanda river valleys. The formation of landslide dams and subsequent breaching is also associated with such rainfall events. These dams may persist for years or may burst within a short span of its formation. Due to sudden surge of water level in the river valleys, havoc and panic are created in the down stream. In Alaknanda valley, frequencies of such extreme rainfall events are found to be increasing in last two decades. However, the monthly trend of extreme rainfall events has partly indicated this increase. In most of the years extreme rainfall events and cloudburst disaster were reported in August during the later part of the monsoon season. [ABSTRACT FROM AUTHOR]

Investigates the levels of runoff and soil loss from steep slopes in Katarmal, India. Effects of rainfall intensity on runoff levels; Implications of grass growth, soil compaction and sediment exhaustion on runoff and soil loss; Efficacy of bioengineering measures in promoting soil conservation.

A correction to the article "Summer monsoon rainfall trends in the Indian Himalayan region" that was published in a previous issue is presented.

In view of complex hydro-geological system and continuous groundwater depletion in mountainous region, there is an urgent need for replenishment groundwater sources in order to secure their long-term sustainability. The current study was aimed to develop a model that will efficiently suggest suitable sites in spring-fed Kosi watershed of Kumaun Himalayas for recharging groundwater. Factors affecting groundwater recharge were found to play a much more complex role in mountainous regions compared to plains due to diversified geological formations, lithological and chronological variations, and complex tectonic framework. In this study, behaviour of influencing factor in complex topographical region has been quantified independently as well as interdependently for identification of cumulative impact of these hydro-geological factors in recharging groundwater. A standard methodology was further developed to identify potential recharge sites by assigning intra-layer weightage and inter-layer score by quantifying the influence of each and every component influencing potential for groundwater recharge using integrated remote sensing (RS) and geographic information system (GIS) technique. Study conducted in Bhatgaon micro-catchment of Kosi basin revealed that 24.1% area fall under the category having good to moderate recharge potential while 61.9% area have poor to moderate recharge potential, hence found less suitable for implementation of artificial recharge structures for conservation of groundwater. A GIS-based recharge and conservation site suitability (RCSS) model was developed with unique query-based codes that would guide for suitable sites in order to implement apposite groundwater augmentation measures for sustentation of Bhatgaon micro-catchment of Kosi basin. Furthermore, this kind of study is very helpful for groundwater managers to found best suitable site for implementing groundwater augmentation measures for long-term sustainability of natural groundwater sources in hilly terrain. [ABSTRACT FROM AUTHOR]

The detailed hydro-chemical study of meltwater draining from Khangri glacier Arunachal Pradesh has been carried out to evaluate the major ion chemistry and weathering processes in the drainage basin. The investigative results shows that the meltwater is almost neutral to slightly acidic in nature with Mg-HCO3-dominated hydro-chemical facies. In glacial meltwater, Ca+ 2 is the most dominated cation followed by Mg+2, Na+, and K+, while HCO3− is the most dominant anion followed by SO42−, NO3−, and Cl−. The dominant cations such as Ca+2 and Mg+2 show a good relation with the minerals abundance of the rocks. Calcite (CaCO3) and biotite [K(Mg,Fe)3AlSi3O10(F,OH)2] are the most abundant minerals in the deformed carbonate-rich metasedimentary rocks near to the snout with some K feldspar (KAlSi3O8) and quartz (SiO2). This suggests Ca+2 have definitely entered into the water due to the dissolution of calcite and Ca feldspar (CaAl2Si2O8), while one of the source of Mg+2 is biotite. Na feldspar (NaAlSi3O8) has contributed towards the availability of sodium ion, while potassium ion is derived from the chemical weathering of K feldspar and biotite. The chemical weathering is the foremost mechanism controlling the hydro-chemistry of the Khangri glacier because of the least anthropogenic interferences. The mineralogy of surrounding rocks is studied to understand better, the rock-water interaction processes, and their contribution towards ionic concentration of meltwater. The meltwater discharge and individual ion flux of the catchment area have also been calculated, to determine the ionic denudation rate for the ablation season. The high elemental ratio of (Ca + Mg)/(Na + K) (7.91 ± 0.39 mg/l) and low elemental ratio of (Na + K)/total cations (0.11 ± 0.004) indicate that the chemical composition of meltwater is mainly controlled by carbonate weathering and moderately by silicate weathering. The scatter plot result between (Ca + Mg) and total cations confirms that carbonate weathering is a major source of dissolved ions in Khangri glacier meltwater. In addition, the statistical analysis was also used to determine the correlation between physical parameters of glacier meltwater which controlled the solute dynamics. [ABSTRACT FROM AUTHOR]