Cyclic sedimentation of the Karharbari Formation (Damuda Group), Talchir Gondwana basin, Orissa

The cyclic arrangement of lithofacies of the Karharbari Formation of the Damuda Group from a part of the Talchir Gondwana basin has been examined by statistical techniques. The lithologies have been condensed into five facies states viz. coarse-, medium-, fine-grained sandstones, shale and coal for the convenience of statistical analyses. Markov chain analysis indicates the arrangement of Karharbari lithofacies in form of fining upward cycles. A complete cycle consists of conglomerate or coarse-grained sandstone at the base sequentially succeeded by medium-and fine-grained sandstones, shale and coal at the top. The entropy analysis categorizes the Karharbari cycles into the C-type cyclicity, which is essentially a random sequence of lithologic states. Regression analysis undertaken in the present study indicates the existence of sympathetic relationship between total thickness of strata (net subsidence) and number and average thickness of sedimentary cycle and antipathic relationship between number and average thickness of sedimentary cycle. These observations suggest that cyclic sedimentation of the Karharbari Formation was controlled by autocyclic process by means of lateral migration of streams activated by intrabasinal differential subsidence, which operated within the depositional basin and the channels carrying coarse grade clastic sediments, which make the cycles thicker, tend to be more common in the areas of maximum subsidence. Clastic sediments issued from the laterally migrating rivers interrupted the cyclic sedimentation of the Karharbari Formation in many instances.     

Mesonic stiff fluid distribution in five dimensional Bianchi type space time

In this paper, we have constructed mesonic stiff fluid cosmological models in five dimensional LRS Bianchi type-I and Bianchi type-VI₀ space times in general theory of relativity. Some physical and geometrical properties of the models are discussed.     

Anisotropic string cosmological models in Lyra’s geometry

In this paper, we constructed some five dimensional LRS Bianchi type-I string cosmological models based on Lyra geometry and studied some physical and geometrical properties of the models.     

Higher dimensional effective stiff fluid cosmological models in scalar tensor theory

Five dimensional LRS Bianchi type-I effective stiff fluid cosmological models in scalar tensor theory of gravitation proposed by Saez and Ballester (Phys. Lett. A 113:467, 1986) are constructed. Further, some physical and geometrical features of these models are discussed.     

Impact of land-use changes on the genesis and evolution of extreme rainfall event: a case study over Uttarakhand,India

In recent years, hot summers (HS) have played an important role in affecting people’s health and causing natural disasters. However, it is not very clear what HS should be attributed to. In order to investigate that, the anomalous of anticyclone associated with HS in the Mediterranean and North China is examined and compared by using data during the time period 1949~2018. Statistical analysis shows that summer temperature in the Mediterranean and North China is revealing a good correlation when removing the global warming trend. The composite results indicate that the anomalous warming during HS over different regions is both dominantly controlled by an anomalous anticyclone, which enhances the subsidence adiabatic heating of the temperature. Furthermore, the subtropical high (STH) variations faithfully represent the fluctuations in summer temperature over the Mediterranean (cor = 0.78) and North China (cor = 0.80). The anticyclonic anomalies over both focus areas are associated with North Atlantic and Northwest Pacific sea surface temperature (sst), respectively. These results indicate that the total influence of the STH position anomaly should be taken into consideration in different places during HS. However, whether such atmosphere-ocean feedback can be improved by numerical experiments is worthy to be further studied.     

Modeling the transport of nutrients and sediment loads into Lake Tahoe under projected climatic changes

The outputs from two General Circulation Models (GCMs) with two emissions scenarios were downscaled and bias-corrected to develop regional climate change projections for the Tahoe Basin. For one model—the Geophysical Fluid Dynamics Laboratory or GFDL model—the daily model results were used to drive a distributed hydrologic model. The watershed model used an energy balance approach for computing evapotranspiration and snowpack dynamics so that the processes remain a function of the climate change projections. For this study, all other aspects of the model (i.e. land use distribution, routing configuration, and parameterization) were held constant to isolate impacts of climate change projections. The results indicate that (1) precipitation falling as rain rather than snow will increase, starting at the current mean snowline, and moving towards higher elevations over time; (2) annual accumulated snowpack will be reduced; (3) snowpack accumulation will start later; and (4) snowmelt will start earlier in the year. Certain changes were masked (or counter-balanced) when summarized as basin-wide averages; however, spatial evaluation added notable resolution. While rainfall runoff increased at higher elevations, a drop in total precipitation volume decreased runoff and fine sediment load from the lower elevation meadow areas and also decreased baseflow and nitrogen loads basin-wide. This finding also highlights the important role that the meadow areas could play as high-flow buffers under climatic change. Because the watershed model accounts for elevation change and variable meteorological patterns, it provided a robust platform for evaluating the impacts of projected climate change on hydrology and water quality.     

Grey analytic hierarchy process applied to effectiveness evaluation for groundwater potential zone delineation

An attempt has been made to identify plausible groundwater potential zones (GWPZ) based on Grey Analytic Hierarchy Process Method (Grey-AHP) using integrated remote sensing and geographic information system. Grey-AHP combines the advantages of classical analytic hierarchy process and grey clustering method for accurate estimation of weight coefficients. The method also examines the effectiveness of GWPZ identification process. The proposed methodology has been applied to the Hirakud canal command area, Odisha (India). Feature layers [e.g. soil type, geology] are utilized for groundwater potential index (GWPI) calculation. The resulting GWPI map has been classified into three GWPZ namely: good, moderate and poor. Effectiveness based on grey clustering method is found to be in between ‘better’ and ‘common’ classes. Value of coefficient of determination (R² = 0.865) supports the obtained effectiveness evaluation result. This analysis demonstrates the potential applicability of the methodology for a general aquifer system.     

Delineation of structural features over a part of the Bay of Bengal using total and balanced horizontal derivative techniques

The present study deals with classical problem of edge detection in potential field data over complex tectonic regime for both shallower and deeper sources, simultaneously. Balanced horizontal derivative (BHD) technique is a latest edge detection concept which delineates edges using balancing of amplitude responses for both shallower and deeper sources. The BHD technique has been validated by comparing with total horizontal derivative (THD) technique. Initially, three different synthetic models have been generated with spherical, cylindrical and vertical prismatic objects at different depths and corresponding gravity responses have been enhanced using BHD and THD techniques. Structural features have been delineated from EIGEN6C4 free-air gravity data using THD and BHD techniques over a part of the Bay of Bengal. Major lineaments have been identified in N–S direction followed by those identified along the NE–SW, NW–SE and E–W directions. Both studies of synthetic models and real gravity data reveal that BHD is an advanced technique than THD.