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101.
Analysis of objective functions used in urban runoff models 总被引:1,自引:0,他引:1
The objective functions used in parameter estimation in urban runoff models are compared by using a method proposed by Diskin and Simon1 and the urban runoff model ILLUDAS. Two sets of objective functions, the first one used by Diskin and Simon in their study and a second one which includes other objective functions are used. Rainfall-runoff data from urban watersheds in the US are used in the study. The results indicate that the least squares criterion is the best among those studied. 相似文献
102.
A.Bhaskara Rao 《Chemical Geology》1987,60(1-4):287-291
Geological studies made in the area of Mara Rosa in Goias State, Brazil, where small occurrences of gold are known in river placers, have revealed an interesting and extensive “lateritised gravel bed” overlying an inexpressive nodular lateritic crust horizon. The gravel has pebbles of vein quartz, quartzites and gneisses, which are interlocked and compacted by intense lateritisation with brown hydrous Fe-oxide (goethite). The underlying nodular crusts grade from deep brown to mottled, and occasionally have cavities. They possibly represent an interface between the bed rock and the gravel bed. The intensity of lateritisation is attributed to the existence of volcanogenic mafic sequences in the rock. The presence of pebbles of the same nature in the small placers with Au, suggest that Au has been dissolved and precipitated during the lateritisation process. Its abundance is mainly restricted to the lateritic gravel bed, which in turn has contributed Au to the stream placers. Thus, it is considered as a new guide horizon for lateritic Au. 相似文献
103.
A.Bhaskara Rao 《Chemical Geology》1987,60(1-4):293-298
The structural classification previously proposed for laterite crusts in field exploration by the author has the objective of: (a) serving as a tool to geological mapping of the bed rock types; (b) recognition of greenstone belt units of economic interest; and (c) demarcation of target areas for mineral exploration. In localities of several small placer gold operations, outcrops of nodular and pisolitic laterite crusts are seen overlain occasionally by breccioid laterite, nodular laterite breccia, mottled cavernous laterite or banded concretionary laterite. Such nodular or pisolitic varieties, rich in goethite, characterise mafic to ultramafic parent rocks in/and greenstone belt units. This type of crust is thus the guide horizon in the laterite profile indicative of Au. Its surface expression accompanying the source rocks is occasionally significant and thus can be a promoter of small-scale mining and a metallotect and guide for exploration programmes. 相似文献
104.
Lateritic soils near Calicut, Kerala, contain halloysite of intermediate hydration, kaolinite, goethite, gibbsite and quartz. The presence of halloysite is responsible for relatively high plasticity and cation-exchange capacity. Fe-hydroxide colloids along with halloysite contribute to significant phosphate uptake by this soil. Composition of local groundwater is consistent with weathering of sodic plagioclase to gibbsite, kaolinite and metastable halloysite. 相似文献
105.
A steady state model of the Somali current including forcing by both the curl and the divergence of the wind stress is discussed.
The model equations are linear, but the results presented are for the one nonlinear case. The grid resolution was 12 km in
the zonal and 24 km in the meridional direction. The streamfunction and velocity potential of the current are presented for
forcing by divergence and compared with a situation when only the curl is present. The results indicate that a two-gyre system
appears in July, a representative month for the summer monsoon, only when divergence is included. Computations with available
data indicate that the divergence is comparable in magnitude to the curl near the location of the Somali current. The model
produces three other important features: (i) strong upwelling off the east coast of Africa, (ii) downwelling over central
Arabian sea and (iii) a strong eastward current in the upper layer towards the interior of the Arabian sea near 12°N. 相似文献
106.
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
107.
D. Atchuta Rao H. V. Ram Babu G. D. J. Sivakumar Sinha 《Pure and Applied Geophysics》1982,120(2):365-374
The self-potential anomaly due to a two-dimensional inclined sheets of finite depth extent has been analysed in the frequency domain using the Fourier transform. Expression for the Fourier amplitude and phase spectra are derived. The Fourier amplitude and phase spectra are analysed so as to evaluate the parameters of the sheet. Application of this method on two anomalies (synthetic and field data) has given good results. 相似文献
108.
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
109.
110.
S.B. Rakesh Kumar Singh Mohan L. Gupta G.V. Rao 《Journal of Volcanology and Geothermal Research》1982,13(3-4)
Direct current resistivity surveys and shallow temperature measurements were carried out for geothermal exploration in a part of Parvati valley, goethermal field, Himachal Pradesh, India. At a few places, the Schlumberger soundings pointed to the presence of a relatively low-resistivity shallow layer, which probably represents fractured and jointed quartzite, saturated with hot/cold water. Wenner resistivity profiles indicate the presence of some possible shallow subsurface lateral hot water channels across the valley at Manikaran. Shallow temperature measurements show a good subsurface thermal anomaly near the confluence of the rivers Brahmaganga and Parvati. The results of the survey, together with other available geodata, suggest that an anomalous heat source does not lie beneath the study area.It is postulated that the meteoric water, originating at high elevations after heating as a result of circulation at depth, emerges at the surface in the Parvati valley as hot springs, after mixing in various proportions with near surface cold waters. 相似文献