Study of thermal properties of supraglacial debris and degree-day factors on Lirung Glacier,Nepal

The extensive debris that covers glaciers in the ablation zone of the Himalayan region plays an important part in regulating ablation rates and water availability for the downstream region. The melt rate of ice is determined by the amount of heat conducted through debris material lying over the ice. This study presents the vertical temperature gradients, thermal properties in terms of thermal diffusivity and thermal conductivity, and positive degree-day factors for the debris-covered portion of Lirung Glacier in Langtang Valley, Nepal Himalaya using field-based measurements from three different seasons.Field measurements include debris temperatures at different debris thicknesses, air temperature, and ice melt during the monsoon(2013), winter(2013), and pre-monsoon(2014) seasons. We used a thermal equation to estimate thermal diffusivity and thermal conductivity, and degree-day factors(DDF) were calculated from cumulative positive temperature and ice melt of the measurement period. Our analysis of debris temperature profiles at different depths of debris show the daily linear gradients of-20.81 °C/m, 4.05 °C/m, and-7.79 °C/m in the monsoon, winter, and pre-monsoon seasons, respectively. The values of thermal diffusivity and thermal conductivity in the monsoon season were 10 times greater than in the winter season. The large difference in these values is attributed to surface temperature and moisture content within the debris. Similarly, we found higher values of DDFs at thinner debris for the pre-monsoon season than in the monsoon season although we observed less melting during the pre-monsoon season. This is attributed to higher cumulative temperature during the monsoon season than in the pre-monsoon season. Our study advances our understanding of heat conductivity through debris material in different seasons, which supports estimating ice melt and discharge from glacierized river basins with debris-covered glaciers in the Himalayan region.     

Advanced oxidation of catechol in reverse osmosis concentrate generated in leather wastewater by Cu–graphite electrode

Reverse osmosis (RO) concentrate generated from tannery was treated by advanced electrochemical oxidation using graphite electrodes. Catechol was selected as model organic pollutant in the RO concentrate. The influence of applied current density, catechol concentration, pH, temperature and inner electrode space of electrodes was investigated in electrochemical oxidation system. The optimized conditions were found to be current density (j), 100 mA/cm²; electrolysis time (t _eco), 60 min; pH, 7.0; and temperature, 25 °C at an inner electrode space, 2 cm. The average mass transport coefficient for the removal of catechol as COD was found to be 3.0 × 10^?5 m/s at optimum conditions. Faradic efficiency and specific energy consumption were also calculated for the applied current density. Further, the treatment of catechol was confirmed through Fourier transform infrared spectroscopy. Theoretical evaluation of current density suggested that the removal of catechol was controlled when supplied at above limiting applied current densities and mass transport controlled at lower of limiting current densities.     

Measurements of radon flux and soil-gas radon concentration along the Main Central Thrust, Garhwal Himalaya, using SRM and RAD7 detectors

Radon in the Earth’s crust or soil matrix is free to move only if its atoms find their way into pores or capillaries of the matrix. ²²²Rn atoms from solid mineral grains get into air, filling pores through emanation process. Then ²²²Rn enters into the atmosphere from air-filled pores by exhalation process. The estimation of radon flux from soil surface is an important parameter for determining the source term for radon concentration modeling. In the present investigation, radon fluxes and soil-gas radon concentration have been measured along and around the Main Central Thrust (MCT) in Uttarkashi district of Garhwal Himalaya, India, by using Scintillation Radon Monitor (SRM) and RAD7 devices, respectively. The soil radon gas concentration measured by RAD7 with soil probe at the constant depth was found to vary from 12 ± 3 to 2330 ± 48 Bq·m^?3 with geometrical mean value of 302 ± 84 Bq·m^?3. Th significance of this work is its usefulness from radiation protection point of view.     

Exploring the Moon in the 21st century

Ian Crawford and Mahesh Anand report on a wide-ranging RAS Discussion Meeting on the future of lunar exploration, held in the Geological Society Lecture Theatre at Burlington House on Friday 11 November 2005.     

Landslide detection in the Himalayas using machine learning algorithms and U-Net

Landslides - Event-based landslide inventories are essential sources to broaden our understanding of the causal relationship between triggering events and the occurring landslides. Moreover,...     

Application of tank,NAM, ARMA and neural network models to flood forecasting

Two lumped conceptual hydrological models, namely tank and NAM and a neural network model are applied to flood forecasting in two river basins in Thailand, the Wichianburi on the Pasak River and the Tha Wang Pha on the Nan River using the flood forecasting procedure developed in this study. The tank and NAM models were calibrated and verified and found to give similar results. The results were found to improve significantly by coupling stochastic and deterministic models (tank and NAM) for updating forecast output. The neural network (NN) model was compared with the tank and NAM models. The NN model does not require knowledge of catchment characteristics and internal hydrological processes. The training process or calibration is relatively simple and less time consuming compared with the extensive calibration effort required by the tank and NAM models. The NN model gives good forecasts based on available rainfall, evaporation and runoff data. The black‐box nature of the NN model and the need for selecting parameters based on trial and error or rule‐of‐thumb, however, characterizes its inherent weakness. The performance of the three models was evaluated statistically. Copyright © 2000 John Wiley & Sons, Ltd.     

Study of Geomagnetic Storms and Solar and Interplanetary Parameters for Solar Cycles 22 and 24

The aim of this paper is to investigate the association of geomagnetic storms with the component of the interplanetary magnetic field (IMF) perpendicular to the ecliptic (\(Bz\)), the solar wind speed (\(V\)), the product of solar wind speed and \(Bz\) (VBz), the Kp index, and the sunspot number (SSN) for two consecutive even solar cycles, Solar Cycles 22 (1986?–?1995) and 24 (2009?–?2017). A comparative study has been done using the superposed epoch method (Chree analysis). The results of the present analysis show that \(Bz\) is a geoeffective parameter. The correlation coefficient between Dst and \(Bz\) is found to be 0.8 for both Solar Cycles 22 and 24, which indicates that these two parameters are highly correlated. Statistical relationships between Dst and Kp are established and it is shown that for the two consecutive even solar cycles, Solar Cycles 22 and 24, the patterns are strikingly similar. The correlation coefficient between Dst and Kp is found to be the same for the two solar cycles (?0.8), which clearly indicates that these parameters are well anti-correlated. For the same studied period we found that the SSN does not show any relationship with Dst and Kp, while there exists an inverse relation between Dst and the solar wind speed, with some time lag. We have also found that VBz is a more relevant parameter for the production of geomagnetic storms, as compared to \(V\) and \(Bz\) separately. In addition, we have found that in Solar Cycles 22 and 24 this combined parameter is more relevant during the descending phase as compared to the ascending phase.     

Increasing trend of northeast monsoon rainfall over the equatorial Indian Ocean and peninsular India

Peninsular India and Sri Lanka receive major part of their annual rainfall during the northeast monsoon season (October–December). The long-term trend in the northeast monsoon rainfall over the Indian Ocean and peninsular India is examined in the vicinity of global warming scenario using the Global Precipitation Climatology Project (GPCP) dataset available for the period 1979–2010. The result shows a significant increasing trend in rainfall rate of about 0.5 mm day^?1 decade^?1 over a large region bounded by 10 °S–10 °N and 55 °E–100 °E. The interannual variability of seasonal rainfall rate over peninsular India using conventional rain gauge data is also investigated in conjunction to the Indian Ocean dipole. The homogeneous rain gauge data developed by Indian Institute of Tropical Meteorology over peninsular India also exhibit the considerable upward rainfall trend of about 0.4 mm day^?1 decade^?1 during this period. The associated outgoing longwave radiation shows coherent decrease in the order of 2 W?m^?2 decade^?1 over the rainfall increase region.     

Favourable geological environments for uranium mineralization, Peninsular Malaysia

An appraisal of the 1977–1978 regional reconnaissance geochemical data obtained under the Central Belt Project indicated that the Boundary Range Granite, the Senting Granite, and the Benom Igneous Complex appear to constitute favourable uranium exploration targets. Results of the airborne survey subsequently flown within the Project area in 1980 showed high radiometric responses over these and other granitoids. Recent follow-up of a multi-element geochemical anomaly over the Boundary Range Granite has resulted in the discovery of some uraninite-bearing boulders and an abnormally radioactive ironstained quartz vein containing uranium-bearing rhabdophane and florencite. Yet another potential target appears to be the Main Range Granite. Although not within the Project area, it has the distinction of hosting the first recorded uranium occurrence in Peninsular Malaysia.Contrary to earlier belief, the importance of the continental Mesozoic Tembeling and Gagau Groups as possible uranium hosts has been reduced, judging from the poor airborne radiometric response and the overall low geochemical results. On the other hand the Tertiary basins, not previously accorded attention, should be assessed.     

Palynology and depositional facet of lower Permian (Artinskian) sediments from New Majri opencast mine,Wardha basin,India

Coal samples and the associated sediments from New Majri open cast mine have been analysed palynologically with the following objectives: to date the sediments on the basis of the palyno-assemblage recognised; to carry out an inter-basinal, intra-basinal and Gondwana wide correlation; to interpret the palaeoenvironment and depositional facet of the coal field on the basis of dispersed organic matter analysis and sedimentary facies analysis. Based on the qualitative and quantitative analysis of the spore and pollen content one palyno-assemblage-Scheuringipollenites and Faunipollenites has been recognised which is typical of lower Barakar Formation. This has been correlated with known palyno-assemblages from Wardha basin and other basins in India, while with the Gondwana continents the assemblage has been broadly correlated with early Permian Australian, African, South America palynofloras as well as early Permian palynoflora of Antarctica. Consequently, a tentative late Early Permian, Artinskian age is proposed for the sediments from New Majri open cast mine. Palynological studies also revealed that the peat forming vegetation was mainly composed of gymnosperms represented by glossopterids (Scheuringipollenites, Ibisporites, Platysaccus, Cuneatisporites, Primuspollenites and Sahnites), conifers (Faunipollenites, Striatites, Striatopodocarpites, Verticipollenites, Distriatites) and cordaites (Parasaccites, Plicatipollenites, Crucisaccites, Divarisaccus, Densipollenites). Spores were represented mainly by filicopsids (Horriditriletes, Brevitriletes, Callumispora) and sphenopsids (Latosporites). The relative abundance of structured organic matter implies the existence of a fairly dense cover of vegetation in the hinterland. Anaerobic, reducing, water logged peat-forming conditions have been inferred by the presence of biodegraded organic matter and amorphous organic matter. The charcoal fragments recovered from the present study area reflects a possible wildfire in the accumulated swamps or a wildfire in the hinterland after which the sediments were flushed by fluvial systems into the swamps. The coalfield exhibits horizontal bedding pattern which may be due to deposition by suspension settling or horizontal accretion. Further the alternating high and low energy regime is noticed in the sandstone-shale intercalated beds overlying the coarse grained yellow sandstone which forms the roof of the coal seam. Comprehensively the sediments are deposited as overbank / levee deposits.