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K. Satish Kumar K. N. S. S. S. Srinivas V. Pradeep Kumar P. Prabhakara Prasad T. Seshunarayana 《Journal of the Geological Society of India》2018,91(2):174-180
High ground magnetic anomalies are observed at western basin of the Sandur schist belt (SSB) near Muraripura village, Karnataka. Sources for these anomalies are inferred due to presence of exposed banded iron formations hosted by metabasalts, arenaous and argillaceous rocks associated with the Donimali Formation of the schist belt. Two varieties of BIF bands are observed in the study area viz. Band 1 and Band 2. The bands 1 and 2 are displaced by lateral strike-slip fault. Band 1 is dominantly composed of banded iron formation, rich in iron ore minerals and silica chert. Band 2 is largely composed of ferruginous quartzite and quartz arenites. Qualitative analysis of the magnetic data indicates that the study area can be divided into three lithologically important BIF/BQ formations. Spectral and quantitative analysis of the magnetic data indicates, the average depth of band 1 is 70 m and band 2 is 130 m. The magnetic data results are well correlated with chemical analysis of borehole and surface rock samples data. 相似文献
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Seasonal and diurnal variability of thermal structure in the coastal waters off Visakhapatnam has been examined in relation
to the flow field and surface winds utilizing the hourly data of temperature and currents taken at a fixed location over a
tidal cycle at monthly intervals. The coastal currents in the pre-monsoon period and strong near-surface winter cooling processes
affect the thermal structure of the coastal sea. Upwelling which is predominant during March to May with an intermittent relaxing
event helps in the development of a strong layered thermal structure while convective mixing due to winter inversions during
November to February causes weak thermal gradients in the water column. 相似文献
3.
P. Prabhakara Rao K. C. C. Raju M. Kareemuddin 《Journal of the Indian Society of Remote Sensing》1982,10(2):45-53
Multi-disciplinary integrated studies were carried out in the drought prone, backward district of Anantapur, for an appraisal of its natural resource and environmental potential, by applying the photointerpretation and remote sensing techniques. Shortage of land and water resources are identified as the major constraints for developmental planning. The natural resources and the potential available for development are documented in various thematic maps. The landuse pattern for agriculture and forestry is mainly controlled by the lithological and morphological units. It is surmised, that with the new source for groend water identified along linement and fracture zones, there is scope for augmenting and uplift the land use and crop-pattern, and this helps to upgrade the socio-economic condition of the district. 相似文献
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Prabhakara Prasad P. Satish Kumar K. Seshunarayana T. Rama Rao Ch. 《Arabian Journal of Geosciences》2014,7(7):2633-2639
Randomly distributed ground magnetic data sets, collected along parallel and closely spaced profiles, in small blocks, the blocks being separated/distributed widely over a large area, become, sometimes, unamenable for deriving a meaningful geological model. In such a situation, an approach of “Cumulative Total Intensity Magnetic Anomaly Field (CTIMAF)” has been devised to interpret the sparsely distributed magnetic data sets. A case history has been presented from the lead–zinc mineralized provenance of Ajabgarh Formation of Delhi Fold Belt in the northern part of Ajmer Town. Log-normalized radially averaged power spectrum was computed for the Cumulative Total Intensity Magnetic Anomaly data and depth to the basement is derived. The computed depth of 4.5 km is in good agreement with the Deep Seismic Studies. 相似文献
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In recent studies (Spencer and Christy, 1990; and Spenceret al., 1990) it is suggested that observations at 53.74 GHz made by the Microwave Sounding Unit (MSU), flown on NOAA operational weather satellites, can yield a precise estimate of global mean temperature and its change as a function of time. Hansen and Wilson (1993) question their interpretation of temporal changes on the grounds that the microwave observations could be influenced by the opacity of the variable constituents in the atmosphere. This issue has broad interest because of the importance of detection of global climatic change.In order to help resolve this issue, in this study we utilize a radiative transfer model to simulate: (a) the observations of MSU Channel 1 (Ch. 1) at 50.3 GHz, in the weakly absorbing region of the 60 GHz molecular oxygen absorption band; and (b) the observations of MSU Channel 2 (Ch. 2) at 53.74 GHz, in the moderately strong absorption region of the same band. This radiative transfer model includes extinction due to clouds and rain in addition to absorption due to molecular oxygen and water vapor.The model simulations show that, over the oceans, extinction due to rain and clouds in Ch. 1 causes an increase in brightness temperature, while in Ch. 2 it causes a decrease. Over the land, however, both Ch. 1 and Ch. 2 show a decrease in brightness temperature due to rain and cloud extinction. These theoretical results are consistent with simultaneous observations in Ch. 1 and Ch. 2 made by MSU. Based on theory and observations we infer that a substantial number of the MSU observations at 53.74 GHz used by Spenceret al. contain rain and cloud contamination. As a result, their MSU derived global mean temperatures and long term trend is questionable. 相似文献
7.
K. Satish Kumar S. Parveen Begum G. S. Srinivas M. Shri Hari Rao P. Prabhakara Prasad T. Seshunarayna R. K. Tiwari 《Journal of the Geological Society of India》2018,92(3):368-372
Ajmer-Sambar sector of Delhi fold belt, North-Central Rajasthan has got importance due to its litho characters, structure, metamorphism, magmatism, migmatisation, metallogeny and rich potential of base metal mineralization. This sector is comprised of Delhi sequence of rocks hosted by the Banded Gneisses Complex (BGC). In view of the significance of this region, ground magnetic survey was conducted along six regional profiles to understand the structural features, magnetic nature of the basement and depth to the basement. Analysis of the magnetic data has clearly identified two magnetic lineaments (a) L1 in WNW-ESE direction that appears to represent litho-contact between Kalyanpura sequences in the south to Anasagar migmatite in the north and (b) L2 in NNW to SSE direction south of Parvatsar which is inferred to be a structural control about which the quartzite rocks of Taragarh Formation culminate. An average depth to basement of 3.7 km is estimated through spectral analysis of magnetic data. The maximum depth of the basin 4.5 km is estimated in central part of the study area. The obtained depth results are in good agreement with the Cummulative Total Intensity Magnetic Anomaly field (CTIMAF) and Deep seismic stuides. 相似文献
8.
C. Prabhakara Jung-Moon Yoo Steven P. Maloney J. J. Nucciarone Albert Arking Maria Cadeddu G. Dalu 《Climatic change》1996,33(4):459-476
Using Microwave Sounding Unit (MSU) channel 2 (Ch. 2, 53.74 GHz) data, Spencer and Christy (1992a) determined that the earth exhibits no temperature trend in the period 1979–90, while other authors find a temperature increase of roughly 0.1 K. Based on a theoretical analysis Prabhakara et al. (1995) showed that the information about the global atmospheric temperature deduced from MSU Ch. 2 observations has a small contamination, T
2, as a result of the attenuation due to hydrometeors in the atmosphere. A method is developed in this study, that utilizes coincident measurements made by MSU in Ch. 1 (50.3 GHz), to estimate this T
2 over the global oceans. The magnitude of T
2 is found to be about 1 K over significant parts of the tropical oceanic rain belts and about 0.25 K over minor portions of the mid-latitude oceanic storm tracks. Due to events such as El Niôo, there is variability from year to year in the rain areas and rain intensity leading to significant change in the patterns of T
2. The patterns of T
2 derived for March 82 and March 83 reveal such a change. When averaged over the global oceans, from 50° N to 50° S, T
2 has a value of 0.25 and 0.29 K for March 1982 and 1983, respectively. Due to these reasons the interannual temperature change derived by Spencer and Christy from MSU Ch. 2 will contain a residual hydrometeor effect. Thus in evaluating decadal trend of the global mean temperature of the order of 0.1 K from MSU Ch. 2 data one has to take into account completely the contamination due to hydrometeors. 相似文献
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The global distribution of total ozone is derived for the period April, May, June and July of 1969 from Nimbus-3 Infrared Interferometer Spectrometer (IRIS) experiment. Preliminary estimates of ozone amounts from Nimbus-4 IRIS for the same period of 1970 show similar results. The standard error of estimation of total ozone from both IRIS experiments is 6% with respect to Dobson Spectrophotometer measurements. A systematic variation in the ozone distribution from April to July in the tropical, middle and polar latitudes is observed indicating the changes in the lower stratospheric circulation.The total ozone measurements show a strong correlation with the upper tropospheric geopotential height in the extratropical latitudes. From this relationship total ozone is used as a quasi-stream function to deduce geostrophic winds at the 200 mb level over extratropical regions of the northern and southern hemispheres. These winds reveal the subtropical and polar jet streams over the globe.Allied research associates. 相似文献