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11.
Electrical resistivity method is a versatile and economical technique for groundwater prospecting in different geological settings due to wide spectrum of resistivity compared to other geophysical parameters. Exploration and exploitation of groundwater, a vital and precious resource, is a challenging task in hard rock, which exhibits inherent heterogeneity. In the present study, two-dimensional Electrical Resistivity Tomography (2D-ERT) technique using two different arrays, viz., pole–dipole and pole–pole, were deployed to look into high signal strength data in a tectonically disturbed hard rock ridge region for groundwater. Four selected sites were investigated. 2D subsurface resistivity tomography data were collected using Syscal Pro Switch-10 channel system and covered a 2 km long profile in a tough terrain. The hydrogeological interpretation based on resistivity models reveal the water horizons trap within the clayey sand and weathered/fractured quartzite formations. Aquifer resistivity lies between ~3–35 and 100–200 Ωm. The results of the resistivity models decipher potential aquifer lying between 40 and 88 m depth, nevertheless, it corroborates with the static water level measurements in the area of study. The advantage of using pole–pole in conjunction with the pole–dipole array is well appreciated and proved worth which gives clear insight of the aquifer extent, variability and their dimension from shallow to deeper strata from the hydrogeological perspective in the present geological context. 相似文献
12.
Understanding the fundamental issues related with the effect of shear velocity on frictional characteristics at the interface
of rock surfaces is an important issue. In this paper, strain-rate dependence on friction is investigated in relation to sliding
behaviour under normal load. The phenomenon of stick-slip of granite and shaly sandstone with a tribometer at constant rate
of strain under normal loads was observed. 相似文献
13.
PATEL DHRUVESH P SRIVASTAVA PRASHANT K GUPTA MANIKA NANDHAKUMAR NARESH 《Journal of Earth System Science》2015,124(1):71-86
Journal of Earth System Science - Watershed morphometric analysis is important for controlling floods and planning restoration actions. The present study is focused on the identification of... 相似文献
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NAND L SHARMA JAGDISH C KUNIYAL MAHAVIR SINGH PRIYANKA SHARMA KESAR CHAND AJAY KUMAR NEGI MANUM SHARMA HARINDER KUMAR THAKUR 《Journal of Earth System Science》2011,120(2):281-290
The concentration of ultrafine aerosol particles of aitken and nucleation mode having size in the range of 1–20 nm was monitored
with water-based Condensation Particle Counter. The monitoring was carried out from midnight-to-midnight in every alternate
day on a fortnightly basis to represent summer, monsoon and winter (autumn) seasons of 2008 at Mohal (1154 m amsl) and Kothi
(2530 m amsl) in Kullu-Manali area of the northwestern Himalayan region of India. The results indicate that diurnal pattern
has faint bimodal structure with two peaks, one in morning and the other in evening at both the sites but it is not as distinct
as found in plains. There is rather a constant particle density pattern of large magnitude consistent with vehicular movement
from morning till evening. The monthly 24 h average particle density gradually picks up from January, increases rapidly in
summer months and then decreases in monsoon season at Mohal but at Kothi it keeps on rising from April to October with a slight
more increase in September. The particle density is more in summer than in monsoon season at Mohal, a trend opposite to plains.
It may be due to the development of warm thermal layer on valley floor while a cold layer develops along snowy hilltops in
winter leading to convection of fine particle up the slopes of valley during daytime. At Kothi, the trend is same as it is
in continental plains but opposite to Mohal. The relatively more value of particle density in September and October at both
the sites may be due to month long International Kullu Dussehra fair in the valley. The vehicular survey conducted agrees
well with entire study period averaged diurnal variations and monthly 24 h averaged value of fine particle density. The average
value of ultrafine particle density at each hour of a day for entire study period is 20369 ± 1230 Ncm − 3 and 14389 ± 1464 Ncm − 3 at Mohal and Kothi sites, respectively. The comparison with earlier results shows a significant increase indicating impact
of vehicular onslaught on pure air of this hilly region. 相似文献
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This study characterizes the black carbon in Agra, India home to the Taj Mahal—and situated in the Indo-Gangetic basin.The mean black carbon concentration is 9.5 μg m~(-3)and, owing to excessive biomass/fossil fuel combustion and automobile emissions, the concentration varies considerably. Seasonally, the black carbon mass concentration is highest in winter, probably due to the increased fossil fuel consumption for heating and cooking, apart from a low boundary layer. The nocturnal peak rises prominently in winter, when the use of domestic heating is excessive. Meanwhile, the concentration is lowest during the monsoon season because of the turbulent atmospheric conditions and the process of washout by precipitation. The ratio of black carbon to brown carbon is less than unity during the entire study period, except in winter(December). This may be because that biomass combustion and diesel exhaust are major black carbon contributors in this region, while a higher ratio in winter may be due to the increased consumption of fossil fuel and wood for heating purposes. ANOVA reveals significant monthly variation in the concentration of black carbon; plus, it is negatively correlated with wind speed and temperature. A high black carbon mass concentration is observed at moderate(1–2 m s~(-1)) wind speed, as compared to calm or turbulent atmospheric conditions. 相似文献
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R SAPRA S K DHAKA V PANWAR R BHATNAGAR K PRAVEEN KUMAR Y SHIBAGAKI M VENKAT RATNAM M TAKAHASHI 《Journal of Earth System Science》2011,120(5):807-823
Relationship of outgoing long-wave radiation (OLR) with convective available potential energy (CAPE) and temperature at the 100-hPa pressure level is examined using daily radiosonde data for a period 1980–2006 over Delhi (28.3°N, 77.1°E) and Kolkata (22.3°N, 88.2°E), and during 1989–2005 over Cochin (10°N, 77°E) and Trivandrum (8.5°N, 77.0°E), India. Correlation coefficient (R xy) between monthly OLR and CAPE shows a significant (~???0.45) anti-correlation at Delhi and Kolkata suggesting low OLR associated with high convective activity during summer (seasonal variation). Though, no significant correlation was found between OLR and CAPE at Cochin and Trivandrum (low latitude region); analysis of OLR and temperature (at 100-hPa) association suggests that low OLR peaks appear corresponding to low temperature at Delhi (R xy~ 0.30) and Kolkata (R xy ~ 0.25) during summer. However, R xy between OLR and temperature becomes opposite as we move towards low latitudes (~8°–10°N) due to strong solar cycle influence. Large scale components mainly ENSO and quasi-biennial oscillaton (QBO) that contributed to the 100-hPa temperature variability were also analyzed, which showed that ENSO variance is larger by a factor of two in comparison to QBO over Indian region. ENSO warm conditions cause warming at 100-hPa over Delhi and Darwin. However, due to strong QBO and solar signals in the equatorial region, ENSO signal seems less effective. QBO, ENSO, and solar cycle contribution in temperature are found location-dependent (latitudinal variability) responding in consonance with shifting in convective activity regime during El Niño, seasonal variability in the tropical easterly jet, and the solar irradiance. 相似文献