Rainfall Estimation from Combined Observations Using KALPANA-IR and TRMM- Precipitation Radar Measurements over Indian Region

In the present study an attempt has been made to improve the rainfall estimation technique developed recently by Mishra et al. (2009a, 2009b) based on KALPANA and Tropical Rainfall Measuring Mission (TRMM)-Precipitation Radar (PR) data over the Indian land and oceanic region. The algorithm for rainfall estimation was basically based on synergistically analyzing the thermal infra-red radiances from Kalpana/INSAT data along with the high resolution, horizontal and vertical rainfall estimates from PR. Presently the augmentation is based on the data base of precipitable water and relative humidity from National Centre for Environmental Prediction-Global forecast System (NCEP-GFS) data as a background field to correct for the biases in earlier algorithm. The algorithm is tested for many case studies of monsoon rainfall over India and adjoining oceanic regions. The rainfall from the present scheme is compared with the standard TRMM-3B42 rain product. The validation with the Automatic Weather Station (AWS) rain gauge and the Global Precipitation and Climatology Project (GPCP) version 2 rain products shows that the present scheme is able to retrieve the rainfall with a very good accuracy. These studies are aimed at the rainfall retrievals in near future from both INSAT-3D and Megha-Tropiques, IR and MW imagers respectively.     

A VLA 20 and 90 centimetre radio survey of distant A-bell clusters with central cD galaxies

A radio survey, using the Very Large Array at 20 and 90 cm λ has been carried out in the direction of 46 distant Abell clusters (0.1 ≲ z ≲ 0.3) dominated by a cD galaxy (clusters classified to be Bautz-Morgan I type). A radio source coincident with the cD galaxy was detected in 16 clusters. We find that the radio luminosity function of the cD galaxies at 20cm λ, and below the luminosityP _1.4ghz ≲ 10^24.5 W Hz^-1, is similar to that of brightest ellipticals in less clustered environments. Above this luminosity, the cDs seem to have a higher probability of becoming radio sources. The effect of optical brightness on radio emission is shown to be the same for the two classes. No significantly large population of very-steep-spectrum sources with spectral index α >1.2 (flux density ∝ frequency^-α) was found to be associated with cD galaxies. A significant negative correlation is found between the radio luminosity of the cD galaxy and the cooling-time of the intra cluster medium near the galaxy. We also present evidence that the probability of radio emission from first-ranked galaxies is dependent upon their location relative to the geometrical centres of clusters and thus related to the morphological class and the evolutionary state of the clusters. We argue that both these effects are primarily caused by the dynamical evolution of these distant clusters of galaxies.     

基于模糊集理论的降雨不确定性传播影响研究

基于模糊集理论,耦合遗传算法,量化分析降雨的量级、空间分布和时程分配产生的不确定性对流量模拟的影响。雨量量级的不确定性使用模糊集概念表示,运用遗传算法对时段雨量在时间上进行随机解集,并通过在各子流域上采用不同的时间解集模式以同时考虑降雨时程分配和空间分布不确定性。应用TOPMODEL对资水流域新宁水文站洪水过程进行模拟研究,结果表明,雨量不确定性的传播对洪水预报的影响处于主导地位,降雨时空分布引起的不确定性对洪水模拟的影响次之。此外,通过对1 h和0.5 h解集结果的比较发现,本文中采用1 h作为模拟的时间步长已可以较充分反映雨量的时间变异性。     

Automatic recognition of geologic prospects

Computer recognition of prospective areas through the processing of digital exploration data can be effective if the statistical tests for the determination of the prospects are pertinent to the presence of the desired mineral. Where exploration involves the application of polynomial trend analysis to structure contour maps in the search for petroleum and natural gas, standard analysis of variance tests may not indicate the best exploration maps. Variance tests may be completely invalid where isolated dips and clustered samples cause the surfaces generated by some of the most common trend programs to oscillate, creating a false impression of variance. On the other hand, tests that directly compare the position of residual features with areas of known production consistently indicate the best map for the determination of new prospects. They are simple to apply and appear to offer the most opportunity for the automatic recognition of prospective areas.     

Revisiting the stratigraphy of the Mesoproterozoic Chhattisgarh Supergroup,Bastar craton,India based on subsurface lithoinformation

In the last 10 years, several teams of geologists from different institutions in India and abroad have vigorously investigated the Chhattisgarh basin (Bastar craton, India). Based on the new results and the lithologs of more than 350 water wells, resistivity and gamma-ray logs, and extensive geological traverses, we present a revised geological map, relevant cross sections, a new comprehensive stratigraphic column and a discussion of the new findings. Major outcomes of this revision are: (1) confirming the existence of two sub-basins (Hirri and Baradwar) and two depocentres; (2) establishing the age of the basin to be essentially Mesoproterozoic; (3) discarding the ‘unclassified Pandaria Formation’ and classifying the package of Pandaria rock units into Chandi, Tarenga, Hirri and Maniari formations in the Hirri sub-basin; (4) accepting the ‘group’ status of the Singhora Group and the newly proposed Kharsiya Groups in the Baradwar sub-basin; (5) establishing an intrabasinal correlation of formations; (6) reappraising the thicknesses of the different formations; and (7) finding that the geometry of the basin is ‘bowl-shaped’, which is compatible with a sag model for the origin and evolution of the basin.     

Settlement of compacted ash fills

The coal ash is a by-product of coal-fired thermal power station. It is extensively used as a geo-material for landfill. The compacted ash is used as a structural fill if it is properly characterized for load-bearing capacity and settlement. The main objective of the present work is to characterize ash material and to evaluate its settlement characteristics. The ash is normally compacted by vibration at or near optimum moisture for its performance as structural fill. The overt characteristics of ashes are viewed similar to cohesionless soils. However, the mass behavior may have differences due to the subtle influence of chemical and physical processes involved in its formation. The empirical and analytical methods predicting settlement of footing under static loading require direct or indirect measurement of density and stress state in the deposit. In the present work, experimental investigations for settlement prediction were carried out on compacted coal ash produced at Ropar thermal power station in India, which was conveniently classified as ASTM class F ash. The settlement was experimentally obtained for the rigid plates having least dimension more than 0.3 m on ashes compacted at varying degree of compaction. The predicted settlement based on the observed data of coal ash using conventional techniques for soils was found to be conservative. A relationship between settlement and foundation size is proposed at varying compaction to obtain the settlement of compacted ash. At a higher degree of compaction, the settlement of a foundation may not exceed the allowable settlements in the working stress range.     

E–W strike slip shearing of Kinwat granitoid at South East Deccan Volcanic Province,Kinwat, Maharashtra,India

We study the margin of South East Deccan Volcanic Province around Kinwat lineament, Maharashtra, India, which is NW extension of the Kaddam Fault. Structural field studies document \(\sim \)E–W strike-slip mostly brittle faults from the basement granite. We designate this as ‘Western boundary East Dharwar Craton Strike-slip Zone’ (WBEDCSZ). At local level, the deformation regime from Kinwat, Kaddam Fault, micro-seismically active Nanded and seismically active Killari corroborate with the nearby lineaments. Morphometric analyses suggest that the region is moderately tectonically active. The region of intense strike-slip deformation lies between seismically active fault along Tapi in NW and Bhadrachalam in the SE part of the Kaddam Fault/lineament. The WBEDCSZ with the surface evidences of faulting, presence of a major lineaments and intersection of faults could be a zone of intraplate earthquake.     

Fractal-based evaluation of the effect of water reservoirs on hydrological processes: the dams in the Yangtze River as a case study

Water reservoirs exercise a considerable influence on hydrological processes and their influence can be treated as one of the influences of human activities on the hydrological cycle at the regional and even global scale. Long daily streamflow series from two gauging stations, Cuntan and Yichang, are analyzed to quantify the effect of the Gezhouba- and the Three Gorges Dams on the Yangtze River flow variations. The Cuntan- and Yichang stations are located up- and downstreams of these two dams, respectively. The quantification entails the employment of conventional multifractal analysis (MFA) and MF-detrended fluctuation analysis (MF-DFA). The streamflow series are divided into six segments based on the time when the Gezhouba- and Three Gorges Dams were constructed. Thus, the effect of these two dams can be compared through MF properties of streamflow before and after the construction of water reservoirs. The effect of the Gezhouba Dam on streamflow downstream may not be reflected by conventional MFA but can be seen from the results of MF-DFA. It should be due to the fact that MF-DFA is on the basis of fluctuations around the dominant trend, reflecting more local information; while the box-counting algorithms investigate the streamflow from the whole view. Particularly, for the inter-station comparison of results obtained by MF-DFA-based analysis, the strongest impact on the streamflow downstream is indicated by the most significant difference in generalized fractal dimension spectrum appearing during the construction of Gezhouba Dam. In addition, after the construction of Gezhouba Dam, the minimal MF dimension at Yichang station start to be less than that at Cuntan station, suggesting that the streamflow becomes less fluctuated, which should be attributed to the filter effect of water reservoir. This study presents a feasible way to evaluate, wholly and locally, the impact of water reservoirs on streamflow in other river basins in the world.