Rainfall-Runoff Modeling using Clustering and Regression Analysis for the River Brahmaputra Basin

In this research, k-means, agglomerative hierarchical clustering and regression analysis have been applied in hydrological real time series in the form of patterns and models, which gives the fruitful results of data analysis, pattern discovery and forecasting of hydrological runoff of the catchment. The present study compares with the actual field data, predicted value and validation of statistical yields obtained from cluster analysis, regression analysis with ARIMA model. The seasonal autoregressive integrated moving average (SARIMA) and autoregressive integrated moving average (ARIMA) models is investigated for monthly runoff forecasting. The different parameters have been analyzed for the validation of results with casual effects. The comparison of model results obtained by K-means & AHC have very close similarities. Result of models is compared with casual effects in the same scenario and it is found that the developed model is more suitable for the runoff forecasting. The average value of R² determined is 0.92 for eight ARIMA models. This shows more accuracy of developed ARIMA model under these processes. The developed rainfall runoff models are highly useful for water resources planning and development.     

Runoff generation mechanisms in pastures of the Sand Mountain region of Alabama—a field investigation

Excessive application of poultry litter to pastures in the Sand Mountain region of north Alabama has resulted in phosphorus (P) contamination of surface water bodies and buildup of P in soils of this region. Since surface runoff is recognized as the primary mechanism of P transport, understanding surface runoff generation mechanisms are crucial for alleviating water quality problems in this region. Identification of surface runoff generation mechanisms is also important for delineation of hydrologically active areas (HAAs). Therefore, the specific objective of this study was to identify surface runoff generation mechanisms (infiltration excess versus saturation excess) using distributed surface and subsurface sensors and rain gauge. Results from three rainfall events (2·13–3·43 cm) of differing characteristics, and sensor data at four locations with differing soil hydraulic properties along the hillslope showed that the main surface runoff generation mechanism in this region is infiltration excess. Because of this, rainfall intensity and soil hydraulic conductivity were found to play dominant roles in surface runoff generation in this region. Further, only short periods of a few rainfall events during which the rainfall intensity is high produce surface runoff. This study indicates that perhaps subsurface flows and transport of P in subsurface flows need to be quantified to reduce P contamination of surface water bodies in this region. Current studies at this location are identifying spatial and temporal distribution of HAAs, quantifying rainfall characteristics that generate runoff, and estimating runoff volume that results from connected HAAs. Copyright © 2008 John Wiley & Sons, Ltd.     

Electron density from Mg VIII emission lines

Mg VIII emission line intensity ratio I (430.47)/I (436.62) has been studied in detail and is found to be an excellent candidate for diagnosing the quiet Sun and the coronal holes.     

Theoretical Ne VI/Mg VI line diagnostics for SUMER

Theoretical Nevi/Mgvi EUV line emissivity ratios, suitable for density-measurements in various solar features such as active regions, sunspots, umbrae and flare plasmas and to be observed in the SUMER spectral range, are presented and their applications discussed with the help of available observational data.     

Nonlinear dynamics of Landau damped kinetic Alfvén waves

In the present paper we have studied the nonlinear dynamical equation of Landau damped kinetic Alfvén wave (KAW) to investigate the nonlinear evolution of KAW and the resulting turbulent spectra in solar wind plasmas. We have introduced a parameter g which governs the coupling between the amplitude of the pump KAW and the density perturbation. The numerical solution has been carried out to see the dependence on the parameter g in the nonlinear part of our equation. Our results reveal the formation of damped localized structures of KAW as well as steepening of the turbulent spectra by increasing g when damping is taken into account. The power spectra of magnetic field fluctuations indicate the redistribution of energy among the higher wave numbers. Each power spectrum with and without damping splits up into two different scaling ranges, Kolmogorov scaling followed by a steeper scaling. The steepening in the power spectra with Landau damping is more than without Landau damping case (for the same value of g). This type of steeper spectra has also been observed in the solar wind and is attributed to the Landau damping effects.     

Application of Artificial Neural Network Model for the Prediction of Suspended Sediment Load in the Large River

Water Resources - Predicting the Suspended Sediment Load (SSL) of the river is a very significant and challenging task. Being a non-linearity in the SSL data, it requires a non-linear method to get...     

Heliospheric Modulation of Galactic Cosmic Rays During Solar Cycle 23

Galactic cosmic rays (GCRs) encounter an outward-moving solar wind with cyclic magnetic-field fluctuation and turbulence. This causes convection and diffusion in the heliosphere. The GCR counts from the ground-based neutron monitor stations show intensity changes that are anti-correlated with the sunspot numbers with a lag of a few months. GCRs experience various types of modulation from different solar activity features and influence space weather and the terrestrial climate. In this work, we investigate certain aspects of the GCR modulation at low cut-off rigidity (R _c≈1 GV) in relation to some solar and geomagnetic indices for the entire solar cycle 23 (1996?–?2008). We separately study the GCR modulation during the ascending phase of cycle 23 including its maximum (1996?–?2002) and the descending phase including its minimum (2003?–?2008). We find that during the descending phase, the GCR recoveries are much faster than those of the solar parameters with negative time-lag. The results are discussed in light of modulation models, including drift effects and previous results.     

Increase of the mean Sun–Earth distance caused by a secular mass accumulation

Based on many planetary observations between the years 1971 and 2003, Krasinsky and Brumberg (Celest. Mech. Dyn. Astron. 90:267–288, 2004) have estimated a rate of increase in the mean Sun-Earth distance of (15±4) m per century. Together with other anomalous observations in the solar system, this increase appears to be unexplained (Lämmerzahl et al. in Astrophys. Space Sci. Lib., vol. 349, pp. 75–101, 2008). We explain these findings by invoking a recently proposed gravitational impact model (Wilhelm et al. in Astrophys. Space Sci. 343:135–144, 2013) that implies a secular mass increase of all massive bodies. This allows us to formulate a quantitative understanding of the effect within the parameter range of the model with a mass accumulation rate of the Sun of (6.4±1.7)×10¹⁰ kg?s^?1.     

Hα and hard X-ray development in two-ribbon flares

Morphological features of two-ribbon flares have been studied, using simultaneous ISEE-3 hard X-ray records and high-resolution Big Bear H movies for more than 20 events. Long-lasting and complex hard X-ray bursts are almost invariably found associated with flares of the two-ribbon type. We find at least three events, namely March 31, 1979, April 10, 1980, and July 1, 1980, where the occurrence of individual spikes in hard X-ray radiation coincides with suddenly enhanced H emission covering the sunspot penumbra. There definitely exist important ( 1B) two-ribbon H flares without significant hard X-ray emission.