Showing papers in "Journal of Earth System Science in 2018"

The monsoon system: Land–sea breeze or the ITCZ?

Abstract: For well over 300 years, the monsoon has been considered to be a gigantic land–sea breeze driven by the land–ocean contrast in surface temperature. In this paper, this hypothesis and its implications for the variability of the monsoon are discussed and it is shown that the observations of monsoon variability do not support this popular theory of the monsoon. An alternative hypothesis (whose origins can be traced to Blanford’s (1886) remarkably perceptive analysis) in which the basic system responsible for the Indian summer monsoon is considered to be the Intertropical Convergence Zone (ITCZ) or the equatorial trough, is then examined and shown to be consistent with the observations. The implications of considering the monsoon as a manifestation of the seasonal migration of the ITCZ for the variability of the Indian summer monsoon and for identification of the monsoonal regions of the world are briefly discussed.

Impact of LULC change on the runoff, base flow and evapotranspiration dynamics in eastern Indian river basins during 1985–2005 using variable infiltration capacity approach

Abstract: As a catchment phenomenon, land use and land cover change (LULCC) has a great role in influencing the hydrological cycle. In this study, decadal LULC maps of 1985, 1995, 2005 and predicted-2025 of the Subarnarekha, Brahmani, Baitarani, Mahanadi and Nagavali River basins of eastern India were analyzed in the framework of the variable infiltration capacity (VIC) macro scale hydrologic model to estimate their relative consequences. The model simulation showed a decrease in ET with 0.0276% during 1985–1995, but a slight increase with 0.0097% during 1995–2005. Conversely, runoff and base flow showed an overall increasing trend with 0.0319 and 0.0041% respectively during 1985–1995. In response to the predicted LULC in 2025, the VIC model simulation estimated reduction of ET with 0.0851% with an increase of runoff by 0.051%. Among the vegetation parameters, leaf area index (LAI) emerged as the most sensitive one to alter the simulated water balance. LULC alterations via deforestation, urbanization, cropland expansions led to reduced canopy cover for interception and transpiration that in turn contributed to overall decrease in ET and increase in runoff and base flow. This study reiterates changes in the hydrology due to LULCC, thereby providing useful inputs for integrated water resources management in the principle of sustained ecology.

GIS-based multi-criteria land suitability analysis for sustainable agriculture in the northeast area of Tadla plain (Morocco)

Abstract: Assessment of soil suitability for sustainable intensive agriculture is an appropriate tool to select the land suitable for agricultural production with the least economic and environmental costs. This study was conducted to evaluate the agricultural soil quality in the northeast area of Tadla plain (Morocco) using geographic information system (GIS) and analytical hierarchy process (AHP). Six soil quality indicators, i.e., pH, organic carbon, cation exchange capacity, texture, salinity and slope were considered and performed in 60 subsurface soil samples. AHP method was utilized to identify the weight of each indicator from the pairwise comparison matrix. The weighted sum overlay analysis was then used to generate the soil quality map in a GIS environment, by overlaying both indicator weights and sub-indicator weights. The studied area was classified into four soil quality categories, i.e., poor, medium, good, and excellent, the percentage of each category is 1.12, 20.98, 61.07 and 16.83%, respectively. The results indicated that 1.12% of the study area has poor suitability for sustainable intensive agriculture due to their unsuitable texture and low salinity, while about 77% of cultivated soils are adapted to agricultural production. The above results could be useful for the management of agricultural activity.

Pedotransfer functions to estimate soil water content at field capacity and permanent wilting point in hot Arid Western India

Abstract: Characterization of soil water retention, e.g., water content at field capacity (FC) and permanent wilting point (PWP) over a landscape plays a key role in efficient utilization of available scarce water resources in dry land agriculture; however, direct measurement thereof for multiple locations in the field is not always feasible. Therefore, pedotransfer functions (PTFs) were developed to estimate soil water retention at FC and PWP for dryland soils of India. A soil database available for Arid Western India (N=370) was used to develop PTFs. The developed PTFs were tested in two independent datasets from arid regions of India (N=36) and an arid region of USA (N=1789). While testing these PTFs using independent data from India, root mean square error (RMSE) was found to be 2.65 and 1.08 for FC and PWP, respectively, whereas for most of the tested ‘established’ PTFs, the RMSE was >3.41 and >1.15, respectively. Performance of the developed PTFs from the independent dataset from USA was comparable with estimates derived from ‘established’ PTFs. For wide applicability of the developed PTFs, a user-friendly soil moisture calculator was developed. The PTFs developed in this study may be quite useful to farmers for scheduling irrigation water as per soil type.

Analysis of rainfall and temperature time series to detect long-term climatic trends and variability over semi-arid Botswana

Abstract: Arid and semi-arid environments have been identified with locations prone to impacts of climate variability and change. Investigating long-term trends is one way of tracing climate change impacts. This study investigates variability through annual and seasonal meteorological time series. Possible inhomogeneities and years of intervention are analysed using four absolute homogeneity tests. Trends in the climatic variables were determined using Mann–Kendall and Sen’s Slope estimator statistics. Association of El Nino Southern Oscillation (ENSO) with local climate is also investigated through multivariate analysis. Results from the study show that rainfall time series are fully homogeneous with 78.6 and 50% of the stations for maximum and minimum temperature, respectively, showing homogeneity. Trends also indicate a general decrease of 5.8, 7.4 and 18.1% in annual, summer and winter rainfall, respectively. Warming trends are observed in annual and winter temperature at 0.3 and 1.5% for maximum temperature and 1.7 and 6.5% for minimum temperature, respectively. Rainfall reported a positive correlation with Southern Oscillation Index (SOI) and at the same time negative association with Sea Surface Temperatures (SSTs). Strong relationships between SSTs and maximum temperature are observed during the El Nino and La Nina years. These study findings could facilitate planning and management of agricultural and water resources in Botswana.

Reliability of reanalyses products in simulating precipitation and temperature characteristics over India

Abstract: Various reanalyses have been utilized in numerous climate related researches around the globe, however, there exists considerable biasedness in these products, especially in precipitation and temperature data. The ability of these reanalysis products to simulate the precipitation and temperature patterns is observed to be satisfactory at global scale, while it differs significantly at regional scale, especially over regions of high spatio-temporal heterogeneity such as India. Therefore, it is essential to evaluate the applicability and robustness of reanalyses in climate related research. The annual and seasonal variability in spatio-temporal patterns and trends of precipitation and temperature data, with respect to the IMD gridded data over 34 yrs, are evaluated for six global reanalyses namely, NCEP/NCAR Reanalysis (NCEP R1), NCEP-DOE AMIP-2 Reanalysis (NCEP R2), Climate Forecast System Reanalysis (CFSR), ECMWF Interim Reanalysis (ERA-Interim), Modern Era Retrospective Analysis for Research and Application Land only model (MERRA-Land) and JMA 55-year Reanalysis (JRA-55). The ability of the reanalyses was tested based on several factors such as statistical and categorical indices, spells and trends, for annual and seasonal daily values. Several regional and seasonal differences were observed, particularly over high rainfall regions such as Western Ghats and northeastern India. MERRA-Land is found to give the best results for precipitation over India, which is attributed to the updated forcing data using gauge-based precipitation observations. Similarly, ERA-Interim and JRA-55 exhibit better performance for temperature than other datasets. All reanalyses failed to correctly reproduce the trends in IMD data, for both precipitation and temperature. These observations will provide a better perception on the reliability and applicability of reanalyses for climate and hydrological studies over India.

Early Neoarchaean A-type granitic magmatism by crustal reworking in Singhbhum craton: Evidence from Pala Lahara area, Orissa

Abstract: Several volumetrically minor $$\sim $$ 2.8 Ga anorogenic granites and rhyolites occur along the marginal part of the Singhbhum craton whose origin and role in crustal evolution are poorly constrained. This contribution presents petrographic, geochemical, zircon U–Pb and trace element, and mineral chemical data on such granites exposed in the Pala Lahara area to understand their petrogenesis and tectonic setting. The Pala Lahara granites are calc-alkaline, high-silica rocks and define a zircon U–Pb age of 2.79 Ga. These granites are ferroan, weakly metaluminous, depleted in Al, Ca and Mg and rich in LILE and HFSE. They are classified as A2-type granites with high Y/Nb ratios. Geochemical characteristics (high $$\hbox {SiO}_{2}$$ and $$\hbox {K}_{2}\hbox {O}$$ , very low MgO, Mg#, Cr, Ni and V, negative Eu anomaly, flat HREE and low Sr/Y) and comparison with melts reported by published experimental studies suggest an origin through high-temperature, shallow crustal melting of tonalitic/granodioritic source similar to the $$\sim $$ 3.3 Ga Singhbhum Granite. Intrusion of the Pala Lahara granites was coeval with prominent mafic magmatism in the Singhbhum craton (e.g., the Dhanjori mafic volcanic rocks and NNE–SSW trending mafic dyke swarm). It is suggested that the $$\sim $$ 2.8 Ga A-type granites in the Singhbhum craton mark a significant crustal reworking event attendant to mantle-derived mafic magmatism in an extensional tectonic setting.

Geochemical assessment of fluoride enrichment and nitrate contamination in groundwater in hard-rock aquifer by using graphical and statistical methods

Abstract: This systematic study was carried out with objective to delineate the various sources responsible for $$\hbox {NO}_{3}^{-}$$ contamination and $$\hbox {F}^{-}$$ enrichment by utilizing statistical and graphical methods. Since Central Ground Water Board, India, indicated susceptibility of $$\hbox {NO}_{3}^{-}$$ contamination and $$\hbox {F}^{-}$$ enrichment, in most of the groundwater, $$\hbox {NO}_{3}^{-}$$ and $$\hbox {F}^{-}$$ concentration primarily observed $${>}45$$ and $${>}1.5~\hbox {mg/L}$$ , respectively, i.e., higher than the permissible limit for drinking water. Water Quality Index (WQI) indicates $${\sim }22.81\%$$ groundwater are good-water, $${\sim }71.14\%$$ groundwater poor-water, $${\sim }5.37\%$$ very poor-water and 0.67% unsuitable for drinking purpose. Piper diagram indicates $${\sim }59.73\%$$ groundwater hydrogeochemical facies are Ca–Mg– $$\hbox {HCO}_{3 }$$ water-types, $${\sim }28.19\%$$ Ca–Mg– $$\hbox {SO}_{4}$$ –Cl water-types, $${\sim }8.72\%$$ Na–K– $$\hbox {SO}_{4}$$ –Cl water-types and 3.36% Na–K– $$\hbox {HCO}_{3 }$$ water-types. This classification indicates dissolution and mixing are mainly controlling groundwater chemistry. Salinity diagram indicate $${\sim }44.30\%$$ groundwater under in low sodium and medium salinity hazard, $${\sim }49.66\%$$ groundwater fall under low sodium and high salinity hazard, $${\sim }3.36\%$$ groundwater fall under very-high salinity hazard. Sodium adsorption ratio indicates $${\sim }97\%$$ groundwater are in excellent condition for irrigation. The spatial distribution of $$\hbox {NO}_{3}^{-}$$ indicates significant contribution of fertilizer from agriculture lands. Fluoride enrichment occurs in groundwater through the dissolution of fluoride-rich minerals. By reducing the consumption of fertilizer and stress over groundwater, the water quality can be improved.

Geomorphic investigation of the Late-Quaternary landforms in the southern Zanskar Valley, NW Himalaya

Abstract: The Suru, Doda and Zanskar river valleys in the semi-arid region of Southern Zanskar Ranges (SZR) preserve a rich repository of the glacial and fluvial landforms, alluvial fans, and lacustrine deposits. Based on detailed field observations, geomorphic mapping and limited optical ages, we suggest four glaciations of decreasing magnitude in the SZR. The oldest Southern Zanskar Glaciation Stage (SZS-4) is inferred from glacially polished bedrock and tillite pinnacles. The SZS-4 is ascribed to the Marine Isotopic Stage (MIS)-4/3. The subsequent SZS-3 is represented by obliterated and dissected moraines, and is assigned to MIS-2/Last Glacial Maximum. The multiple recessional moraines of SZS-2 glaciation are assigned the early to mid Holocene age whereas, the youngest SZS-1 moraines were deposited during the Little Ice Age. We suggest that during the SZS-2 glaciation, the Drang-Drung glacier shifted its course from Suru Valley (west) to the Doda Valley (east). The study area has preserved three generations of outwash gravel terraces, which broadly correlate with the phases of deglaciation associated with SZS-3, 2, and 1. The alluvial fan aggradation, lacustrine sedimentation, and loess deposition occurred during the mid-to-late Holocene. We suggest that glaciation was driven by a combination of the mid-latitude westerlies and the Indian Summer Monsoon during periods of cooler temperature, while phases of deglaciation occurred during enhanced temperature.

Assessing climate change impacts on river hydrology – A case study in the Western Ghats of India

Abstract: The objective of this study is to evaluate the hydrological impacts of climate change on rainfall, temperature and streamflow in a west flowing river originating in the Western Ghats of India. The long-term trend analysis for 110 yr of meteorological variables (rainfall and temperature) was carried out using the modified Mann–Kendall trend test and the magnitude of the trend was quantified using the Sen’s slope estimator. The Regional Climate Model (RCM), COordinated Regional climate Downscaling EXperiment (CORDEX) simulated daily weather data of baseline (1951–2005) and future RCP 4.5 scenarios (2006–2060) were used to run the hydrological model, Soil and Water Assessment Tool (SWAT), in order to evaluate the effect of climate change on rainfall, temperature and streamflow. Significant changes were observed with regard to rainfall, which have shown decreasing trend at the rate of 2.63 mm per year for the historical and 8.85 mm per year for RCP 4.5 future scenarios. The average temperature was found to be increasing at $$0.10\,^{\circ }\hbox {C}$$ per decade for both historical and future scenarios. The impact of climate change on the annual streamflow yielded a decreasing trend at the rate of $$1.2\,\hbox {Mm}^{3}$$ per year and 2.56 $$\hbox {Mm}^{3},$$ respectively for the past and future scenarios. The present work also investigates the capability of SWAT to simulate the groundwater flow. The simulated results are compared with the recession limb of the hydrograph and were found to be reasonably accurate.

An assessment on oil spill trajectory prediction: Case study on oil spill off Ennore Port

Abstract: A Liquefied Petroleum Gas (LPG) tanker and a chemical tanker collided two nautical miles off Ennore port on 28 January, 2017. Around 196.4 metric tons (MT) of Heavy Furnace Oil (HFO) was spilled and drifted towards the shore. Oil spill drift advisory and prediction was made by Indian National Centre for Ocean Information Services (INCOIS) using General National Oceanic and Atmospheric Administration (NOAA) Operational Modeling Environment (GNOME), an oil spill trajectory model. The trajectory model was forced with analysed and forecasted ocean currents from Global Ocean Data Assimilation System (GODAS) based on Modular Ocean Model 4p1 (GM4p1). It was found that spread of HFO obtained from oil spill trajectory model GNOME, has matched well with the observed spread from Sentinel-1A satellite dataset. However, the spread of the HFO was underestimated by the trajectory model, when forced with forecasted GM4p1 currents. Additional ground truth observation from Indian Coast Guard also corroborates this finding.

Application of instantaneous spectral analysis and acoustic impedance wedge modeling for imaging the thin beds and fluids of fluvial sand systems of Indus Basin, Pakistan

Abstract: Fluvial sand frameworks have magnificent oil and gas reservoirs far and wide. The reservoir sands are exceedingly compartmentalized by the broadened fault framework. So, to distinguish the thin beds of gas-bearing facies is an assessment for band-limited stratigraphic investigation. To conquest this issue, we execute the progressed seismic ascribe methods to the 3D seismic information of the Miano area of the Indus Basin, SW Pakistan. Apparatuses, for example, the seismic amplitude and coherence are discovered less exact for reservoir description. Sweetness analysis indicates the gas-bearing reservoir facies, which are compartmentalized by the NNW–SSE oriented normal fault system. Yet, the continuous wavelet transforms (CWT) of spectral decomposition (SD) separates the thick and thin sand beds of channel sand and point bars, which were not unsurprising utilizing the band-limited seismic properties. 22 Hz demonstrates the best amplitude tuning cube, which recognizes the profitable clastic (sand-filled barrier bars) sequences. The net-to-gross (N/G) examination uncovers the barrier bars as the chief hydrocarbon-bearing facies. 22 to 37 Hz frequencies confirm the occurrence of hydrocarbon sands. The acoustic impedance (AI) wedge model settles the thin beds of barrier bars sands, which are encased inside the shales, and affirm the suggestions for gas-bearing stratigraphic traps.

New paleomagnetic results on $$\sim $$ ∼ 2367 Ma Dharwar giant dyke swarm, Dharwar craton, southern India: implications for Paleoproterozoic continental reconstruction

Abstract: Here we report new paleomagnetic results and precise paleopole position of the extensional study on $$\sim $$ 2367 Ma mafic giant radiating dyke swarm in the Dharwar craton, southern India. We have sampled 29 sites on 12 dykes from NE–SW Karimnagar–Hyderabad dykes and Dhone–Gooty sector dykes, eastern Dharwar craton to provide unambiguous paleomagnetism evidence on the spectacular radiating dyke swarm and thereby strengthening the presence of single magmatic event at $$\sim $$ 2367 Ma. A total of 158 samples were subjected to detailed alternating field and thermal demagnetization techniques and the results are presented here along with previously reported data on the same dyke swarm. The remanent magnetic directions are showing two components, viz., seven sites representing four dykes show component (A) with mean declination of $$94{{}^{\circ }}$$ and mean inclination of $$-\,70{{}^{\circ }}$$ ( $$\hbox {k}=87$$ , $$\upalpha _{95}=10{{}^{\circ }}$$ ) and corresponding paleopole at $$16{{}^{\circ }}\hbox {N}$$ , $$41{{}^{\circ }}\hbox {E}$$ ( $$\hbox {dp}=15{{}^{\circ }}$$ and $$\hbox {dm}=17{{}^{\circ }}$$ ) and 22 sites representing 8 dykes yielded a component (B) with mean declination of $$41{{}^{\circ }}$$ and mean inclination of $$-\,21{{}^{\circ }}$$ ( $$\hbox {k}=41$$ , $$\upalpha _{95}=9{{}^{\circ }}$$ ) with a paleopole at $$41{{}^{\circ }}\hbox {N}$$ , $$200{{}^{\circ }}\hbox {E}$$ ( $$\hbox {dp}=5{{}^{\circ }}$$ and $$\hbox {dm}=10{{}^{\circ }}$$ ). Component (A) results are similar to the previously reported directions from the $$\sim $$ 2367 Ma dyke swarm, which have been confirmed fairly reliably to be of primary origin. The component (B) directions appear to be strongly overprinted by the 2080 Ma event. The grand mean for the primary component (A) combined with earlier reported studies gives mean declination of $$97{{}^{\circ }}$$ and mean inclination of $$-\,79{{}^{\circ }}$$ ( $$\hbox {k}=55$$ , $$\upalpha _{95}=3{{}^{\circ }}$$ ) with a paleopole at $$15{{}^{\circ }}\hbox {N}$$ , $$57{{}^{\circ }}\hbox {E}$$ ( $$\hbox {dp}=5{{}^{\circ }}$$ , $$\hbox {dm}=6{{}^{\circ }}$$ ). Paleogeographical position for the Dharwar craton at $$\sim $$ 2367 Ma suggests that there may be a chance to possible spatial link between Dharwar dykes of Dharwar craton (India), Widgemooltha and Erayinia dykes of Yilgarn craton (Australia), Sebanga Poort Dykes of Zimbabwe craton (Africa) and Karelian dykes of Kola-Karelia craton (Baltica Shield).

Moment of inertia for rock blocks subject to bookshelf faulting with geologically plausible density distributions

Abstract: Moment of Inertia (MOI) for rock blocks that glided smoothly into book-shelf dispositions are deduced considering realistic linear and exponential 3D variations in density along specific axes/directions. Knowing (empirical) algebraic relations of density with depth, which could also be anything other than the exponential and linear variations considered in this work, geoscientists can deduce the MOI by following the same process. MOI for a homogeneous parallelepiped block along any direction is proportional to the length of the block in that direction. However, this simple relation does not hold true for rock blocks with variable densities. Nevertheless, as the block length increases, the MOI along that direction would also increase.

Prediction of fog/visibility over India using NWP Model

Abstract: Frequent occurrence of fog in different parts of northern India is common during the winter months of December and January. Low visibility conditions due to fog disrupt normal public life. Visibility conditions heavily affect both surface and air transport. A number of flights are either diverted or cancelled every year during the winter season due to low visibility conditions, experienced at different airports of north India. Thus, fog and visibility forecasts over plains of north India become very important during winter months. This study aims to understand the ability of a NWP model (NCMRWF, Unified Model, NCUM) with a diagnostic visibility scheme to forecast visibility over plains of north India. The present study verifies visibility forecasts obtained from NCUM against the INSAT-3D fog images and visibility observations from the METAR reports of different stations in the plains of north India. The study shows that the visibility forecast obtained from NCUM can provide reasonably good indication of the spatial extent of fog in advance of one day. The fog intensity is also predicted fairly well. The study also verifies the simple diagnostic model for fog which is driven by NWP model forecast of surface relative humidity and wind speed. The performance of NWP model forecast of visibility is found comparable to that from simple fog model driven by NWP forecast of relative humidity and wind speed.

Early Permian transgressive–regressive cycles: Sequence stratigraphic reappraisal of the coal-bearing Barakar Formation, Raniganj Basin, India

Abstract: The present research is an attempt to assess the Barakar Formation of the Raniganj Gondwana Basin, India, in the frame of fluvio-marine (estuarine) depositional systems using sequence stratigraphic elements. Analysis of predominant facies associations signify deposition in three sub-environments: (i) a river-dominated bay-head delta zone in the inner estuary, with transition from braided fluvial channels (FA-B1) to tide-affected meandering fluvial channels and flood plains (FA-B2) in the basal part of the succession; (ii) a mixed energy central basin zone, which consists of transitional fluvio-tidal channels (FA-B2), tidal flats, associated with tidal channels and bars (FA-B3) in the middle-upper part of the succession; and (iii) a wave-dominated outer estuary (coastal) zone (FA-B4 with FA-B3) in the upper part of the succession. Stacked progradational (P1, P2)–retrogradational (R1, R2) successions attest to one major base level fluctuation, leading to distinct transgressive–regressive (T–R) cycles with development of initial falling stage systems tract (FSST), followed by lowstand systems tract (LST) and successive transgressive systems tracts (TST-1 and TST-2). Shift in the depositional regime from regressive to transgressive estuarine system in the early Permian Barakar Formation is attributed to change in accommodation space caused by mutual interactions of (i) base level fluctuations in response to climatic amelioration and (ii) basinal tectonisms (exhumation/sagging) related to post-glacial isostatic adjustments in the riftogenic Gondwana basins.

Carbon dioxide, water vapour and energy fluxes over a semi-evergreen forest in Assam, Northeast India

Abstract: The eddy covariance method is a powerful technique for quantification of $$\hbox {CO}_{2},$$ $$\hbox {H}_{2}$$ O and energy fluxes in natural ecosystems. Leaf area index (LAI) and its changes are significant drivers of $$\hbox {CO}_{2}$$ and $$\hbox {H}_{2}$$ O exchange in a forest ecosystem due to their role in photosynthesis. The present study reports the seasonal variation of $$\hbox {CO}_{2}$$ and energy fluxes and their relationship with other meteorological parameters of a semi-evergreen primary forest of Kaziranga National Park, Assam, India during February 2016–January 2017. The diurnal pattern of half hourly average $$\hbox {CO}_{2 }$$ fluxes over the forest was found to be mostly dominated by the incident photosynthetically active radiation. During the period of study, diurnal variations of $$\hbox {CO}_{2}$$ flux showed a maximum value of $$-9.97\,\upmu $$ mol $$\hbox {m}^{-2}\hbox {s}^{-1}$$ in the month of June during summer which is also the beginning of the monsoon season. The monthly averaged diurnal $$\hbox {CO}_{2}$$ flux and variation in LAI of the forest canopy closely followed each other. The annual net ecosystem exchange of the forest estimated from the $$\hbox {CO}_{2}$$ flux data above the canopy is 84.21 g C $$\hbox {m}^{-2}\,\hbox {yr}^{-1}$$ . Further studies are in progress to confirm these findings. The estimated average annual evapotranspiration of the semi-evergreen forest is 2.8 ± 0.19 mm $$\hbox {day}^{-1}$$ . The study of partitioning of energy fluxes showed the dominance of latent heat fluxes over sensible heat fluxes. The energy balance closure was found to increase with an increase in instability and the highest closure of around 83% was noted under neutral conditions.

Semi-empirical model for retrieval of soil moisture using RISAT-1 C-Band SAR data over a sub-tropical semi-arid area of Rewari district, Haryana (India)

Abstract: We have estimated soil moisture (SM) by using circular horizontal polarization backscattering coefficient ( $$\sigma ^{\mathrm{o}}_{\mathrm{RH}}$$ ), differences of circular vertical and horizontal $$\sigma ^{\mathrm{o}} \, (\sigma ^{\mathrm{o}}_{\mathrm{RV}} {-} \sigma ^{\mathrm{o}}_{\mathrm{RH}})$$ from FRS-1 data of Radar Imaging Satellite (RISAT-1) and surface roughness in terms of RMS height ( $${\hbox {RMS}}_{\mathrm{height}}$$ ). We examined the performance of FRS-1 in retrieving SM under wheat crop at tillering stage. Results revealed that it is possible to develop a good semi-empirical model (SEM) to estimate SM of the upper soil layer using RISAT-1 SAR data rather than using existing empirical model based on only single parameter, i.e., $$\sigma ^{\mathrm{o}}$$ . Near surface SM measurements were related to $$\sigma ^{\mathrm{o}}_{\mathrm{RH}}$$ , $$\sigma ^{\mathrm{o}}_{\mathrm{RV}} {-} \sigma ^{\mathrm{o}}_{\mathrm{RH}}$$ derived using 5.35 GHz (C-band) image of RISAT-1 and $${\hbox {RMS}}_{\mathrm{height}}$$ . The roughness component derived in terms of $${\hbox {RMS}}_{\mathrm{height}}$$ showed a good positive correlation with $$\sigma ^{\mathrm{o}}_{\mathrm{RV}} {-} \sigma ^{\mathrm{o}}_{\mathrm{RH}} \, (R^{2} = 0.65)$$ . By considering all the major influencing factors ( $$\sigma ^{\mathrm{o}}_{\mathrm{RH}}$$ , $$\sigma ^{\mathrm{o}}_{\mathrm{RV}} {-} \sigma ^{\mathrm{o}}_{\mathrm{RH}}$$ , and $${\hbox {RMS}}_{\mathrm{height}}$$ ), an SEM was developed where SM (volumetric) predicted values depend on $$\sigma ^{\mathrm{o}}_{\mathrm{RH}}$$ , $$\sigma ^{\mathrm{o}}_{\mathrm{RV}} {-} \sigma ^{\mathrm{o}}_{\mathrm{RH}}$$ , and $${\hbox {RMS}}_{\mathrm{height}}$$ . This SEM showed $$R^{2}$$ of 0.87 and adjusted $$R^{2}$$ of 0.85, multiple R=0.94 and with standard error of 0.05 at 95% confidence level. Validation of the SM derived from semi-empirical model with observed measurement ( $${\hbox {SM}}_{\mathrm{Observed}}$$ ) showed root mean square error (RMSE) = 0.06, relative-RMSE (R-RMSE) = 0.18, mean absolute error (MAE) = 0.04, normalized RMSE (NRMSE) = 0.17, Nash–Sutcliffe efficiency (NSE) = 0.91 ( $${\approx } 1$$ ), index of agreement (d) = 1, coefficient of determination $$(R^{2}) = 0.87$$ , mean bias error (MBE) = 0.04, standard error of estimate (SEE) = 0.10, volume error (VE) = 0.15, variance of the distribution of differences $$({\hbox {S}}_{\mathrm{d}}^{2}) = 0.004$$ . The developed SEM showed better performance in estimating SM than Topp empirical model which is based only on $$\sigma ^{\mathrm{o}}$$ . By using the developed SEM, top soil SM can be estimated with low mean absolute percent error (MAPE) = 1.39 and can be used for operational applications.

Earth fissures in Qinglong Graben in Yuncheng Basin, China

Abstract: Qinglong Graben is located in southeastern Yuncheng Basin, China flanked by two north-east trending normal faults, where the geological condition is favourable for generating earth fissures. Since 1978, five earth fissures have formed in Qinglong Gaben. In the present work, a series of geological investigation consisting of site investigation, geological drilling and trench excavation was used to characterise and determine the reasons for the formation of the earth fissures. The site investigation indicated that the trend of the five earth fissures are parallel to the general strike of the normal fault, i.e., geological drilling and trench studies revealed that syn-sedimentary fault is the key reason for the formation of the earth fissures. Additionally, over-exploitation of groundwater and erosion process are important factors in the development and expansion of the earth fissures in Qinglong Graben. The earth fissures forming process in Qinglong Graben can be divided into three stages: the regional extension first caused normal faults under the surface, and then the pumping action of excessive groundwater induced the normal faults propagate to the surface, and finally the erosion promoted the formation of the current earth fissure.

Assessing the response of runoff to climate change and human activities for a typical basin in the Northern Taihang Mountain, China

Abstract: Climate change and human activities are the two main factors on runoff change. Quantifying the contribution of climate change and human activities on runoff change is important for water resources planning and management. In this study, the variation trend and abrupt change point of hydro-meteorological factors during 1960–2012 were detected by using the Mann–Kendall test and Pettitt change-point statistics. Then the runoff was simulated by SWAT model. The contribution of climate change and human activities on runoff change was calculated based on the SWAT model and the elasticity coefficient method. The results showed that in contrast to the increasing trend for annual temperature, the significant decreasing trends were detected for annual runoff and precipitation, with an abrupt change point in 1982. The simulated results of SWAT had good consistency with observed ones, and the values of $$R^{2}$$ and $$E_{NS}$$ all exceeded 0.75. The two methods used for assessing the contribution of climate change and human activities on runoff reduction yielded consistent results. The contribution of climate change (precipitation reduction and temperature rise) was $${\sim }37.5\%$$ , while the contribution of human activities (the increase of economic forest and built-up land, hydrologic projects) was $${\sim }62.5\%$$ .

PSHA of Van province for performance assessment using spectrally matched strong ground motion records

Abstract: Within the framework of the performance based earthquake engineering, site specific earthquake spectra for Van province has been obtained It is noteworthy that, in probabilistic seismic hazard assessment, as a first stage data from geological studies and records from the instrumental period were compiled to make a seismic source characterization for the study region The probabilistic seismic hazard curves were developed based on selected appropriate attenuation relationships, at rock sites, with a probability of exceedance 2, 10 and 50% in 50 yrs period The obtained results are compared with the spectral responses proposed for seismic evaluation and retrofit of building structure in Turkish Earthquake Code (2007), section 7 The acceleration response spectrums obtained from probabilistic seismic hazard analysis are matched to adjust earthquake accelerograms recorded during the 2011 Van earthquakes by using SeismoMatch v20 software The aim of this procedure is to obtain a set of reasonable earthquake input motions for the seismic evaluation of existing buildings

Assessment of co-seismic landslide susceptibility using LR and ANCOVA in Barpak region, Nepal

Abstract: Nepal was affected by a catastrophic earthquake with Mw 7.8 on 25th April, 2015 with its epicenter in the central part of Barpak village. A number of co-seismic landslides were triggered by the main shock of the event and associated aftershocks. Due to the rugged topography and vicinity of the main shock, the village was extremely affected by co-seismic landslides. In total, 59 landslides were identified using Google Earth and were verified during the field survey in Barpak village. Furthermore, 11 conditioning factors, including Peak ground acceleration (PGA), epicenter proximity, fault proximity, geology, slope, elevation, plan curvature, profile curvature, topographic wetness index, drainage proximity and the sediment transport index were selected as independent variables for analysis. In this study, logistic regression (LR) and analysis of covariance (ANCOVA) models were used and their performance was assessed. Finally, the landslide susceptibility classes were produced and an evaluation of models was done by using receiver operating characteristic curves. The area under the curve for LR and ANCOVA showed 85.38 and 78.4% accuracy, respectively. Based on the overall assessments, the LR model was more accurate than the ANCOVA model for co-seismic landslide prediction in the study area. The result of this study can be used to mitigate landslide-induced hazards and for land-use planning.

Effects of straw mulching on soil evaporation during the soil thawing period in a cold region in northeastern China

Abstract: To study the effect of straw mulching on soil water evaporation, it is necessary to measure soil water evaporation under different conditions of straw mulching during the soil thawing period. A field experiment was conducted in winter, and soil evaporation was measured using a microlysimeter on bare land (LD) and 4500 (GF4500), 9000 (GF9000) and 13500 $$\hbox {kg/hm}^{2}$$ (GF13500) straw mulch. The influence of different quantities of straw mulch on soil water evaporation during the thawing period was analyzed using the Mallat algorithm, statistical analysis and information cost function. The results showed that straw mulching could delay the thawing of the surface soil by 3–6 d, decrease the speed at which the surface soil thaws by 0.40–0.80 cm/d, delay the peak soil liquid water content, increase the soil liquid water content, reduce the cumulative evaporation by 2.70–7.40 mm in the thawing period, increase the range of soil evaporation by 0.04–0.10 mm in the early stage of the thawing period, and reduce the range of soil evaporation by 0.25–0.90 mm in the late stage of the thawing period. Straw mulching could reduce the range of and variation in soil evaporation and can reduce the effect of random factors on soil evaporation. When the amount of straw mulch exceeded 9000 $$\hbox {kg/hm}^{2}$$ , the effect of increasing the amount of straw mulch on daily soil water evaporation was small.

Quantification of groundwater–surface water interactions using environmental isotopes: A case study of Bringi Watershed, Kashmir Himalayas, India

Abstract: Environmental isotopes including $${\updelta }^{18}$$ O, $${\updelta }^{2}$$ H and $$^{3}$$ H of precipitation, streams and springs were determined in the mountainous Bringi catchment of Kashmir Himalaya, dominated by carbonate lithology. The isotopic signature of winter precipitation is reflected in stream and spring water in late spring and is, therefore, representative of snow melting. The spring waters in September bear the enriched isotopic signatures of summer rainfall. The strong correlation ( $$r^{2} = 0.97$$ ) between the isotopic composition of streams and springs indicates the streams and springs either share similar catchments or the springs are recharged by the streams. Chloride mass balance and isotopic mass balance studies suggest that the surface recharge component averages 337.35 m $$^{3}$$ /s, which is about 75% of total stream discharge during the high flow period. Similarly, the contribution of surface water to groundwater recharge during the low flow period averages 7.5 m $$^{3}$$ /s, which is about 18.6% of total stream flow. Furthermore, the mean residence time of the springs calculated from the tritium decay equation is very short (<1 year). The residence time is longer for Kongamnag and short for Achabalnag, which is further supported by dye testing.

Evaluation of indicators for desertification risk assessment in part of Thar Desert Region of Rajasthan using geospatial techniques

Abstract: Desertification has emerged as a major economic, social and environmental problem in the western part of India. The best way of dealing with desertification is to take appropriate measures to arrest land degradation, especially in areas prone to desertification. This requires an early warning system for desertification based on scientific inputs. Hence, in the present study, an attempt has been made to develop a comprehensive model for the assessment of desertification risk in the Jodhpur district of Rajasthan, India, using 23 desertification indicators. Indicators including soil, climate, vegetation and socio-economic parameters were integrated into a GIS environment to get environmental sensitive areas (ESAs) to desertification. Desertification risk index (DRI) was calculated based on ESAs to desertification, the degree of land degradation and significant desertification indicators obtained from the stepwise multiple regression model. DRI was validated by using independent indicators such as soil organic matter content and cation exchange capacity. Multiple regression analysis shows that 16 indicators out of 23 were found to be significant for assessing desertification risk at a 99% confidence interval with $$R^{2}=0.83$$ . The proposed methodology provides a series of effective indicators that would help to identify where desertification is a current or potential problem, and what could be the actions to alleviate the problem over time.

An approach of understanding acid volcanics and tuffaceous volcaniclastics from field studies: A case from Tadpatri Formation, Proterozoic Cuddapah basin, Andhra Pradesh, India

Abstract: The lower stratigraphic part of the Cuddapah basin is marked by mafic and felsic volcanism. Tadpatri Formation consists of a greater variety of rock types due to bimodal volcanism in the upper part. Presence of bimodal volcanism is an indication of continental rift setting. Various genetic processes involved in the formation of such volcanic sequence result in original textures which are classified into volcaniclastic and coherent categories. Detailed and systematic field works in Tadpatri–Tonduru transect of SW Cuddapah basin have provided information on the physical processes producing this diversity of rock types. Felsic volcanism is manifested here with features as finger print of past rhyolite-dacite eruptions. Acid volcanics, tuffs and associated shale of Tadpatri Formation are studied and mapped in the field. With supporting subordinate studies on geochemistry, mineralogy and petrogenesis of the volcanics to validate field features accurately, it is understood that volcanism was associated with rifting and shallow marine environmental condition. Four facies (i.e., surge, flow, fall and resedimented volcaniclastic) are demarcated to describe stratigraphic units and volcanic history of the mapped area. The present contribution focuses on the fundamental characterization and categorization of field-based features diagnostic of silica-rich volcanic activities in the Tadpatri Formation.

Modelling forest resilience in Hindu Kush Himalaya using geoinformation

Abstract: Resilience is the capacity of an ecosystem to absorb disturbance and undergo change while maintaining its essential structure, functions, identity and feedbacks. The forests of the Hindu Kush Himalayan (HKH) region are vulnerable to both natural and anthropogenic changes, and the forest land conversion and degradation. Using satellite-derived tree canopy cover percent data and precipitation as the explaining variable, we studied the forest cover resilience in a geospatial framework employing the logistic regression and polynomial equation fitting. Out of the $$4.3\,\hbox {million km}^{2}$$ geographical areas, $$873{,}650\,\hbox {km}^{2}$$ (20.20%) was under the forest in 2000 and experienced loss of $$11{,}250\,\hbox {km}^{2}$$ during 2000–2010. We could model the forest cover and treeless areas fairly than the scrub and grassland owing to the variation in precipitation pattern. The majority of the forest cover (59.3%) has been estimated to have less resilience owing to the receipt of <1650 mm of total annual precipitation, whereas only $$375\,\hbox {km}^{2}$$ forest area could change to scrub that shows the least resilience. About 94.4% of treeless areas were estimated to be stable, while only 1% $$(25{,}200\,\hbox {km}^{2})$$ area could accommodate the grassland. The resilient forest areas estimated and observed, owing to the mapping and modelling protocols used in this study, shall be useful in conservation planning in the HKH region.

Structures and morphotectonic evolution of the frontal fold–thrust belt, Kameng river section, Arunachal Himalaya, India

Abstract: The Neogene–Quaternary Siwalik foreland fold and thrust belt is studied for better understanding of tectonics along the Kameng river section of Arunachal Pradesh, India. The Kimi, Dafla, Subansiri, and the Kimin Formation correspond to Lower, Middle and Upper Siwaliks, respectively. The lithology in the foreland basin is dominantly sandstones, siltstones, claystones, carbonaceous shales, and boulder beds in the upper part. The structural style of the sedimentary sequence from the Main Boundary Thrust southward shows first order ramp-flat geometry. The brittle shear transfers slip across glide horizons to shallower depth. Repeated splay generations from a major regional-scale floor transfers slip from one glide horizon to another that shortens and thickens the crust. In the micro-scale, the lithological response in the structural development is well documented as pressure solution seams and other diagenetic deformation signatures. The basement asperity plays a significant role as the moving thrust front produced a major lateral ramp. The differential movement of the mountain front on both sides of the ramp is decipherable. This is especially true at the western part of the SE flowing Kameng river. The tectonic evolution of the area initiated with slip along the MBT $$\sim $$ 11 Ma ago along with the deposition of the Siwalik sediments. With southward propagation of the mountain front, the foreland basin shifted towards S, produced splay thrusts from the Himalayan Frontal Thrust-1 (HFT-1), which has been uplifting the Kimin and the older terraces.

Reassembly of the Dharwar and Bastar cratons at ca. 1 Ga: Evidence from multiple tectonothermal events along the Karimnagar granulite belt and Khammam schist belt, southern India

Abstract: The northern part of the Nellore–Khammam schist belt and the Karimnagar granulite belt, which are juxtaposed at high angle to each other have unique U–Pb zircon age records suggesting distinctive tectonothermal histories. Plate accretion and rifting in the eastern part of the Dharwar craton and between the Dharwar and Bastar craton indicate multiple and complex events from 2600 to 500 Ma. The Khammam schist belt, the Dharwar and the Bastar craton were joined together by the end of the Archaean. The Khammam schist belt had experienced additional tectonic events at $$\sim $$ 1900 and $$\sim $$ 1600 Ma. The Dharwar and Bastar cratons separated during development of the Pranhita–Godavari (P–G) valley basin at $$\sim $$ 1600 Ma, potentially linked to the breakup of the Columbia supercontinent and were reassembled during the Mesoproterozoic at about 1000 Ma. This amalgamation process in southern India could be associated with the formation of the Rodinia supercontinent. The Khammam schist belt and the Eastern Ghats mobile belt also show evidence for accretionary processes at around 500 Ma, which is interpreted as a record of Pan-African collisions during the Gondwana assembly. From then on, southern India, as is known today, formed an integral part of the Indian continent.

Episodic crustal growth in the Bundelkhand craton of central India shield: Constraints from petrogenesis of the tonalite–trondhjemite–granodiorite gneisses and K-rich granites of Bundelkhand tectonic zone

Abstract: Tonalite–trondhjemite–granodiorite gneisses (TTG) and K-rich granites are extensively exposed in the Mesoarchean to Paleoproterozoic Bundelkhand craton of central India. The TTGs rocks are coarse- grained with biotite, plagioclase feldspar, K-feldspar and amphibole as major constituent phases. The major minerals constituting the K-rich granites are K-feldspar, plagioclase feldspar and biotite. They are also medium to coarse grained. Mineral chemical studies show that the amphiboles of TTG are calcic amphibole hastingsite, plagioclase feldspars are mostly of oligoclase composition, K-feldspars are near pure end members and biotites are solid solutions between annite and siderophyllite components. The K-rich granites have biotites of siderophyllite–annite composition similar to those of TTGs, plagioclase feldspars are oligoclase in composition, potassic feldspars have $$\hbox {X}_{\mathrm{K}}$$ ranging from 0.97 to 0.99 and are devoid of any amphibole. The tonalite–trondhjemite–granodiorite gneiss samples have high $$\hbox {SiO}_{2}$$ (64.17–74.52 wt%), $$\hbox {Na}_{2}\hbox {O}$$ (3.11–5.90 wt%), low Mg# (30–47) and HREE contents, with moderate $$(\hbox {La/Yb})_{\mathrm{CN}}$$ values (14.7–33.50) and Sr/Y ratios (4.85–98.7). These geochemical characteristics suggest formation of the TTG by partial melting of the hydrous basaltic crust at pressures and depths where garnet and amphibole were stable phases in the Paleo-Mesoarchean. The K-rich granite samples show high $$\hbox {SiO}_{2}$$ (64.72–76.73 wt%), $$\hbox {K}_{2}\hbox {O}$$ (4.31–5.42), low $$\hbox {Na}_{2}\hbox {O}$$ (2.75–3.31 wt%), Mg# (24–40) and HREE contents, with moderate to high $$(\hbox {La/Yb})_{\mathrm{CN}}$$ values (9.26–29.75) and Sr/Y ratios (1.52–24). They differ from their TTG in having elevated concentrations of incompatible elements like K, Zr, Th, and REE. These geochemical features indicate formation of the K-granites by anhydrous partial melting of the Paleo-Mesoarchean TTG or mafic crustal materials in an extensional regime. Combined with previous studies it is interpreted that two stages of continental accretion (at 3.59–3.33 and 3.2–3.0 Ga) and reworking (at 2.5–1.9 Ga) occurred in the Bundelkhand craton from Archaean to Paleoproterozoic.