We estimate a new angular velocity for the India plate and contemporary deformation rates in the plate interior and along its seismically active margins from Global Positioning System (GPS) ...measurements from 1996 to 2015 at 70 continuous and 3 episodic stations. A new India-ITRF2008 angular velocity is estimated from 30 GPS sites, which include stations from western and eastern regions of the plate interior that were unrepresented or only sparsely sampled in previous studies. Our newly estimated India-ITRF2008 Euler pole is located significantly closer to the plate with ~3% higher angular velocity than all previous estimates and thus predicts more rapid variations in rates and directions along the plate boundaries. The 30 India plate GPS site velocities are well fit by the new angular velocity, with north and east RMS misfits of only 0.8 and 0.9 mm/yr, respectively. India fixed velocities suggest an approximate of 1-2 mm/yr intra-plate deformation that might be concentrated along regional dislocations, faults in Peninsular India, Kachchh and Indo-Gangetic plain. Relative to our newly-defined India plate frame of reference, the newly estimated velocities for 43 other GPS sites along the plate margins give insights into active deformation along India's seismically active northern and eastern boundaries.
The lack of a standardized database of eddy covariance observations has been an obstacle for data-driven estimation of terrestrial carbon dioxide fluxes in Asia. In this study, we developed such a ...standardized database using 54 sites from various databases by applying consistent postprocessing for data-driven estimation of gross primary productivity (GPP) and net ecosystem carbon dioxide exchange (NEE). Data-driven estimation was conducted by using a machine learning algorithm: support vector regression (SVR), with remote sensing data for 2000 to 2015 period. Site-level evaluation of the estimated carbon dioxide fluxes shows that although performance varies in different vegetation and climate classifications, GPP and NEE at 8 days are reproduced (e.g., r (exp 2) =0.73 and 0.42 for 8 day GPP and NEE). Evaluation of spatially estimated GPP with Global Ozone Monitoring Experiment 2 sensor-based Sun-induced chlorophyll fluorescence shows that monthly GPP variations at subcontinental scale were reproduced by SVR (r (exp 2)=1.00, 0.94, 0.91, and 0.89 for Siberia, East Asia, South Asia, and Southeast Asia, respectively). Evaluation of spatially estimated NEE with net atmosphere-land carbon dioxide fluxes of Greenhouse Gases Observing Satellite (GOSAT) Level 4A product shows that monthly variations of these data were consistent in Siberia and East Asia; meanwhile, inconsistency was found in South Asia and Southeast Asia. Furthermore, differences in the land carbon dioxide fluxes from SVR-NEE and GOSAT Level 4A were partially explained by accounting for the differences in the definition of land carbon dioxide fluxes. These data-driven estimates can provide a new opportunity to assess carbon dioxide fluxes in Asia and evaluate and constrain terrestrial ecosystem models.
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 (
r
2
= 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.
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–HCO
3
−
, and the other is a mixed Ca–Mg–Cl
−
paradigm. It perceived that hydro-chemical facies Ca–Mg–Cl
−
was shifted into Ca–Mg–HCO
3
−
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
−
, SO
4
2−
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).
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.
In the Himalaya, natural hazards are common and their places, as well as timings, are difficult to predict. Rough terrain, unpredictable weather conditions and poor road networks of the Himalaya make ...the mitigation measures even more challenging as well as difficult. On April 4, 2023, 7 people have died and 13 were injured due to a small loose snow avalanche at 14th Mile, on the way to Nathula Pass, near Indo-China Border in Sikkim state (India). State government had advised the people, not to visit the area due to the poor weather conditions. However, people have ignored this precious advice and lost their lives. Along with Indo-China border, the region is famous for its scenic beauty. In addition, the region is one of the most difficult border areas with the limited infrastructural development for armed forces. The present study explores the causes and consequences of this killer avalanche from an environmental determinism. The results suggest that, due to the western disturbances, the region received heavy snowfall. Higher average temperature and flowing stream beneath snow, make the snow unstable. Weight of humans put pressure on the weak snow which led to formation of avalanche. Our finding suggests that peoples’ negligence about government advices have led to casualties. The purpose of this case study is to highlight the human folly which invites such unfortunate incidences across the globe. Further, this study emphasis the need of public-government partnership to minimize the impact of such upcoming hazards.
•Present paper deals with causes and consequences of a small loose snow avalanche, occurred at Nathula Pass, India.•This paper highlights human's negligence that converted a natural phenomenon into a hazard which claimed 7 people lives.•Paper suggests some essential remedial measures that may help to minimize the impact of these unknown hazards in future.
The study was focused on the systematic investigation of forest cover mapping and the maximum normalized difference vegetation index (NDVImax) pattern. The study was to support the conservation and ...sustainable management of vital ecosystems by integrating remote sensing and geographic information systems techniques into mountain ecosystem accounting. The study used remote sensing technologies and satellite imagery data, which provides a valuable means to monitor and assess the status and changes in mountain ecosystems. The NDVImax cover study area declined from 44.90 % in 2015 to 43.75 % in 2019, which resulted in a 1.15-square-kilometer reduction in the area with green cover. The percentage of areas such as flood-bare land (0.46 %), scrub land (21.64 %), crop land (4.28 %), built-up areas (1.33 %), bare land (14.7 %), water (1.05 %), wet area (0.05 %), and snow/glacier and snow cover (14.12 %) were used to categorize the land use land cover (LULC) pattern. According to the initial analysis of the MODIS annual mean temperature, in 2015, the satellite sensors recorded a minimum land surface temperature (LST) of −15.3 °C and a maximum value of 33.1 °C. In the additional analysis of the MODIS annual mean temperature in 2019, the sensors recorded a minimum and a maximum LST value of −14.3 °C and 33.4 °C, respectively. The maximum annual mean temperature increased by 0.4 °C between 2015 and 2019 in terms of the annual mean LST. The study revealed the potential to inform policies and strategies for safeguarding mountain ecosystems in the face of ongoing environmental challenges and provide decision-makers with valuable insight.
•The study is to provide decision-makers with valuable insights and outcomes to support the conservation.•Study assessed that sustainable management of these vital ecosystems by integrating remote sensing and geographic information systems techniques into mountain ecosystem accounting maps for the entire study area region.•NDVI is used to assess the strategies for safeguarding mountain ecosystems in the face of ongoing environmental challenges study in the lower Himalaya.
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–HCO
3
and Mg–HCO
3
dominated hydrochemical facies. In meltwater, Ca
2+
and HCO
3
−
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 (Ca
2+
, Mg
2+
, 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/km
2
/ablation during 2015 and 2016, respectively, whereas the anion denudation rate was found to be 205.43 in 2015 and 170.24 ton/km
2
/ablation in 2016.
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) (
C
v
= 1.17) than SSC (
C
v
= 0.54) because computation of SSL includes both discharge (
C
v
= 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 m
3
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/km
2
, and consequent catchment denudation rate was measured as 0.85 mm. A strong positive correlation (
r
2
= 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.
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.
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