Relationship between interplanetary field/plasma parameters with geomagnetic indices and their behavior during intense geomagnetic storms

This paper presents a correlative study between the peak values of geomagnetic activity indices (Dst, Kp, ap and AE) and the peak values of various interplanetary field (Bt, Bz, E and σ_B) and plasma (T, D, V, P and β) parameters along with their various products (BV, BzV and B²V) during intense geomagnetic storms (GMSs) for rising, maximum and decay phases as well as for complete solar cycle 23. The study leads to the conclusion that the peak values of different geomagnetic activity indices are in good correlation with Bt, Bz, σ_B, V, E, BV, BzV and B²V, therefore these parameters are most useful for predicting GMSs and substorms. These parameters are also reliable indicators of the strength of GMSs. We have also presented the lag/lead time analysis between the maximum of Dst and peak values of geomagnetic activity indices, various interplanetary field/plasma parameters for all GMSs. We have found that the average of peak values of geomagnetic activity indices and various field/plasma parameters are larger in decay phase compare to rising and maximum phases of cycle 23. Our analyses show that average values of lag/lead time lie in the ≈?4.00 h interval for Kp, ap and AE indices as well as for Bt, Bz, σ_B, E, D and P. For a more meaningful analysis we have also presented the above study for two different groups G1 (CME-driven GMSs) and G2 (CIR-driven GMSs) separately. Correlation coefficients between various interplanetary field/plasma parameters, their various products and geomagnetic activity indices for G1 and G2 groups show different nature. Three GMSs and associated solar sources observed during three different phases of this solar cycle have also been studied and it is found that GMSs are associated with large flares, halo CMEs and their active regions are close to the solar equator.     

Drinking and irrigational feasibility of groundwater,GIS spatial mapping in upper Thirumanimuthar sub-basin,Cauvery River,Tamil Nadu

In the present study, the chemical characteristics of groundwater with respect to drinking and Irrigation water quality in upper Thirumanimuthar sub-basin, Cauvery River, have been studied. 51 groundwater samples were collected and analysed for pH, conductance, total dissolved solids, total hardness, calcium, magnesium, carbonate, bicarbonate, total alkalinity, chloride, sodium, potassium, sulphate etc. The values analyzed were evaluated in detail and compared with WHO water quality standards. It is observed that, for most of the groundwater quality parameters, the values are not potable for drinking and irrigational use. To understand the spatial distribution of unsuitable zones, ArcGIS was employed. Attributes were linked and spatial interpolation mapping was done. Inverse distance weighted interpolation technique was followed for raster and vector mapping. Finally the overlay analyses were also carried out to locate the worst quality zone.     

Numerical model and flume experiments of single- and two-layered hillslope flow related to slope failure

A hillslope flow model is developed considering 3D saturated and unsaturated flow of water during rainfall events. A finite difference-based numerical model of hillslope flow processes is developed. Four different experiments are done to see the effects of a single- and double-layered soil in pore-water pressure dynamics and slope failure. Results from the numerical model are verified with experimental results. The numerical and experimental values of the pore-water pressure and moisture contents are in good agreement. The results show that the hillslope heterogeneity caused by multiple layers of soil has greater influence on hillslope pore-pressure dynamics and slope failure patterns. The depth of slope failure shows high dependency on layering characteristics of the soil slope and pattern of rainfall. The proposed model provides a perspective on failure mechanism of a single- or double-layered slope under rainfall infiltration.     

Simulation of severe thunder storm event: a case study over Pune,India

Numerical simulation of a typical tropical thunder storm event at Pune (18.53°N, 73.85°E), India, has been performed using the three nested domain configuration of Weather Research and Forecasting-Advanced Research Weather Model (version 3.2). The model simulations have been compared with observations. Sensitivity to cumulus parameterization schemes, namely Betts–Miller (BM), Grell–Devenyi (GD), and Kain–Fritsch (KF), for simulation of vertical structure and time evolution of weather parameters has been evaluated using observations from automatic weather station and global positioning system radiosonde ascents. Comparison of spatial distribution of 24-h accumulated rain with Tropical Rainfall Measuring Mission data shows that BM scheme could simulate better rain than GD and KF schemes. The BM scheme could well simulate the development of storm and heavy rain as it could generate sufficiently humid and deep layer in the lower and middle atmosphere, along with co-existence of updrafts and downdrafts and frozen hydrometeors at the middle level and rain water near the surface.