Evaluation of hydrological effect of stakeholder prioritized climate change adaptation options based on multi-model regional climate projections

An integrated process involving participatory and modelling approaches for prioritizing and evaluating climate change adaptation options for the Kangsabati reservoir catchment is presented here. We assess the potential effects of climate change on water resources and evaluate the ability of stakeholder prioritized adaptation options to address adaptation requirements using the Water Evaluation And Planning (WEAP) model. Two adaptation options, check dams and increasing forest cover, are prioritized using pair-wise comparison and scenario analysis. Future streamflow projections are generated for the mid-21^st century period (2021–2050) using four high resolution (~25 km) Regional Climate Models and their ensemble mean for SRES A1B scenario. WEAP simulations indicate that, compared to a base scenario without adaptation, both adaptation options reduce streamflow. In comparison to check dams, increasing forest cover shows greater ability to address adaptation requirements as demonstrated by the temporal pattern and magnitude of streamflow reduction. Additionally, over the 30 year period, effectiveness of check dams in reducing streamflow decreases by up to 40 %, while that of forest cover increases by up to 47 %. Our study highlights the merits of a comparative assessment of adaptation options and we conclude that a combined approach involving stakeholders, scenario analysis, modelling techniques and multi-model projections may support climate change adaptation decision-making in the face of uncertainty.     

Integrated biological control of water hyacinths, Eichhornia crassipes by a novel combination of grass carp, Ctenopharyngodon idella (Valenciennes, 1844), and the weevil, Neochetina spp.

The efficacy of grass carp Ctenopharyngodon idella (Cyprinidae) and weevils Neochetina spp. (Curculionidae) to control the aquatic weed, water hyacinth, is investigated in a square net cage (happas) setting at a farm in Cuddalore District, South India. This novel combination of insects and fish is found to be superior to individual treatments for controlling the weed growth within 110 d. The biomass of the weed, number of plants, percentage of flowered plants and chlorophyll contents were studied. The weed biomass is reduced from 5 kg (day 1) to 0.33 kg (day 110) when exposed to grass carp and weevils. The number of plants is reduced to 0.75 in grass carp and weevil exposed happas, while it is 741.5 in the control. The mean number of leaves per plant is also reduced. In addition, the chlorophyll a and b are significantly reduced in happas exposed to the combination of fish and insects when compared to the other treatments. Based on the results of this study, we consider the combined use of grass carp and weevils to be more efficient and sustainable for managing water hyacinths than the use of these organisms individually.     

Average anisotropy characteristics of high energy cosmic ray particles and geomagnetic disturbance index Ap

The average characteristics of the diurnal and semi-diurnal anisotropy of cosmic ray intensity at relativistic energies have been obtained by using data from the worldwide grid of neutron monitor for the period 1989 to 1996. The complex behaviour of the diurnal amplitudes and time of maxima (phase) and its association with the Ap index on a long-term and day-to-day basis have been studied. Even though the general characteristics, on a yearly average basis, have not changed significantly during this period, both the diurnal and semi-diurnal amplitudes and phases vary significantly, besides significant changes being observed for different interplanetary conditions on a short-term basis. It is found that the relationship between the Ap index and the diurnal vector is out of phase during the period 1991 to 1995. On a long-term basis, the correlation of diurnal variation with Ap index has been found to vary during the solar cycle. On a short-term basis, it has been observed that the high Ap days are usually associated with higher amplitudes with phase shifted to earlier hours.     

Radioactive quartz-pebble conglomerates from western margin of Bonai granite pluton,Sundargarh district,Orissa — A new find

Several radioactive quartz-pebble conglomerate (QPC) occurrences at the western margin of Archaean Bonai granite and overlying Iron Ore Group (IOG) rocks have recently been located over a total strike length of 8–10 km intermittently in a NE-SW to E-W trend with steep dips due north-west to north in parts of Sundargarh district of Orissa. The QPC samples have analysed up to 0.039% U₃O₈ and 0.035% ThO₂ with high concentration of Y (74 to 518 ppm), La(<100 to 880 ppm), Cr ( 126 to 633 ppm), Zr (137 to 1250 ppm) and Pb (31 to 581 ppm). Cellulose Nitrate (CN) film studies of few QPC samples indicated adsorbed uranium over goethite and infiltrated ferruginous material (limonite), secondary uranium as encrustation and fracture filling and discrete sub-rounded grains of monazite, zircon, allanite and rare xenotime in the matrix of QPC as radioactive phases. Higher content of Th over U, elevated concentration of Y and La in QPC eliminates the possibility of its low temperature product by epigenetic processes. Poor correlation of U with elements like Pb, Y, Zr, La and Cr can be explained due to surficial leaching of uranium from QPC after its deposition as reflected by adsorbed U over iron-oxides and low U/Th ratio in QPC in the area.     

Detection of sub-basaltic sediments by a multi-parametric joint inversion approach

In many parts of the world sedimentary horizons with potential for hydrocarbon are located below flood basalt provinces. However, the presence of high velocity basaltic overburden makes delineation of sediments difficult due to the low velocity layer problem. Electrical and electromagnetic methods have been used in such scenarios because of the good electrical conductivity contrast between basalts and underlying sediments. However, mapping of the target sediments becomes difficult when the layer is thin as the data errors due to inherent noise lead to equivalent solutions. To tackle such difficult situations, a joint inversion scheme incorporating seismic reflection and refraction, magnetotelluric and deep electrical resistivity datasets is presented. Efficacy of the scheme is tested for a model comprising a thin sedimentary layer sandwiched between a thick basalt cover and a granitic basement. The results indicate that the parameters of the target sedimentary layer are either poorly resolved or equivalent solutions are obtained by the inversion of individual datasets. Joint inversions of seismic reflection (RFLS) and refraction (RFRS), or DC and MT dataset pairs provide improved results and the range of equivalent solutions is narrowed down. Combination of any three of the above datasets leads to further narrowing of this range and improvements in mean model estimates. Joint inversion incorporating all the datasets is found to yield good estimates of the structure. Resolution analysis is carried out to appraise estimates of various model parameters obtained by jointly inverting different combinations of datasets.     

Isotope–geochemical characterization and geothermometrical modeling of Uttarakhand geothermal field,India

Uttarakhand geothermal area, located in the central belt of the Himalayan geothermal province, is one of the important high temperature geothermal fields in India. In this study, the chemical characteristics of the thermal waters are investigated to identify the main geochemical processes affecting the composition of thermal waters during its ascent toward the surface as well as to determine the subsurface temperature of the feeding reservoir. The thermal waters are mainly Ca–Mg–HCO₃ type with moderate silica and TDS concentrations. Mineral saturation states calculated from PHREEQC geochemical code indicate that thermal waters are supersaturated with respect to calcite, dolomite, aragonite, chalcedony, quartz (SI > 0), and undersaturated with respect to gypsum, anhydrite, and amorphous silica (SI < 0). XRD study of the spring deposit samples fairly corroborates the predicted mineral saturation state of the thermal waters. Stable isotopes (δ¹⁸O, δ²H) data confirm the meteoric origin of the thermal waters with no oxygen-18 shift. The mixing phenomenon between thermal water with shallow ground water is substantiated using tritium (³H) and chemical data. The extent of dilution is quantified using tritium content of thermal springs and non-thermal waters. Classical geothermometers, mixing model, and multicomponent fluid geothermometry modeling (GeoT) have been applied to estimate the subsurface reservoir temperature. Among different classical geothermometers, only quartz geothermometer provide somewhat reliable estimation (96–140 °C) of the reservoir temperature. GeoT modeling results suggest that thermal waters have attained simultaneous equilibrium with respect to minerals like calcite, quartz, chalcedony, brucite, tridymite, cristobalite, talc, at the temperature 130 ± 5 °C which is in good agreement with the result obtained from the mixing model.     

Multivariate statistical approach for assessment of subsidence in Jharia coalfields,India

Indian coalfields, one of the major coal producers, are facing serious problem of subsidence now-a-days. This paper attempts to investigate various factors and their influence on magnitude and extent of subsidence. The study was conducted in the Jharia coalfields, India where extraction of thick seams at shallow depths has damaged the ground surface in the form of subsidence. For precise pre-estimation of subsidence, it is therefore necessary to know the contribution of each factor to the occurrence of subsidence. In order to achieve the objectives of this study, several multivariate statistical techniques such as factor analysis (FA), principal component analysis (PCA) and cluster analysis (CA) have been used. Two factors were extracted using FA. Factor 1 and factor 2 account for 42.327% and 24.661% of the variability respectively. Factor 1 represents “natural factor” whereas factor 2 represents “subsidence coefficient”. Spatial variations in regarding susceptibility to the subsidence were determined from hierarchical CA using the linkage distance. Further, the findings of this study would be helpful for prediction of magnitude of subsidence empirically.     

Chemical characterization of water-soluble aerosols in different residential environments of semi aridregion of India

This paper deals with the atmospheric concentrations of PM₅ and PM_2.5 particulate matter and its water soluble constituents along with the size distribution of ions and spatial variation at three different residential environments in a semiarid region in India. Samples were collected from the indoors and outdoors of urban, rural and roadside sites of Agra during October 2007–March 2008. The mean concentrations of PM_2.5 indoors and outdoors were 178 μgm⁻³ and 195 μgm⁻³ while the mean concentrations of PM₅ indoors and outdoors were 231.8 μgm⁻³ and 265.2 μgm⁻³ respectively. Out of the total aerosol mass, water soluble constituents contributed an average of 80% (33% anions, 50% cations) in PM₅ and 70% (29% anions, 43% cations) in PM_2.5. The indoor–outdoor ratio of water soluble components suggested additional aerosol indoor sources at rural and roadside sites. Indoor–outdoor correlations were also determined which show poor relationships among concentrations of aerosol ions at all three sites. Univariate Pearson correlation coefficients among water soluble aerosols were determined to evaluate the relationship between aerosol ions in indoor and outdoor air.     

IMF BY dependence of the extent of substorm westward electrojet

In this paper the duskward extension of the westward auroral electrojet is investigated for substorm intervals on the basis of magnetograms recorded at the Indian Antarctic station, Maitri. The database comprises three years from 1998–2000. Based on an initial study of the magnetograms, an arbitrary local time of 2030 MLT is fixed to define the early manifestation of the substorm westward electrojet. Using this criterion 12 substorms are identified and the possible causes examined. Many of these events are observed to be associated with a moderate to intense ring current. The hourly average of the GSM B_Y-component of the interplanetary magnetic field (IMF) for the hour preceding the substorm onset at Maitri is negative for most of the events. It is suggested that the azimuthal shift of the auroral electrojets in the southern hemisphere resulting from a negative B_Y-component of the IMF influences the extent of the substorm westward electrojet. This finding implies that the IMF may have a role in controlling the longitudinal extent of substorm occurrence.     

Stereo Cartosat-1 satellite remote sensing data in assessing topographic potential of soil erosion

Stereo Cartosat-1 satellite data was processed to generate high spatial resolution digital elevation model (DEM) using ground control points (GCPs) collected through geodetic single frequency GPS in differential GPS mode. DEM was processed to generate bare earth DEM by removing heights of natural and man made features from DEM. The bare earth DEM was further analysed in GIS environment to generate terrain-topographic indices viz. wetness index (WI), stream power index (SPI) and sediment transport index (STI) to characterize topographic potential of soil erosion. Hillslopes in the studied watershed (part of Shiwalik hills of Dehradun district, Uttarakhand state) were characterized as low wetness index values indicating dry areas whereas high wetness index values at lower reaches of the watershed indicating as possible source areas for generation of saturated overland flow. Higher STI values were observed in hilly as well as upper part of the piedmont plain and at along sides of the streams in upper piedmont indicating areas susceptible to severe soil erosion. GIS based these topographic indices provided an easy and quick appraisal and scientific basis to identify spatial variability of soil erosion risk in a hilly watershed.