Database management and analysis for CAPE project using remote sensing and GIS

The present study attempts to conceptualise an approach to integrate the remotely sensed and spatial?n-spatial data generated over the years under Crop Acreage and Production Estimation (CAPE) project through GIS for their easy retrieval and comparison; and to develop a program in dBASE to calculate crop acreage using non-spatial attributes imported from GIS. The “Crop Information System” thus developed would help the planners in analysis/comparison of the database related to crops over the years.     

Estimation of site response functions for the central seismic gap of Himalaya,India

Natural Hazards - In the analysis of seismic hazards of a particular region, the site response functions play a significant role. Site response functions for the central seismic gap become more...     

Estimation of Natural Radionuclides and Exhalation Rate in Surface Soils of Four Districts of Haryana,India

A fossil wood of Lagerstroemia L. from the Upper Siwalik sediments of Arunachal Pradesh is described. The genus is recorded for the first time from this state. The modern analog of the fossil species i.e. L. tomentosa C. Presl is not found in the fossil locality at present.. The most plausible reason for the disappearance of the species from the fossil locality is an increase in temperature seasonality caused by the upheaval of the Himalaya during the Pleistocene.     

Performance of Scrap Tire Shreds as a Potential Leachate Collection Medium

The use of scrap-tire-shreds as leachate collection layer in landfills would reduce the magnitude of the current tire disposal problem by converting a waste into a beneficial material. Laboratory studies were conducted to investigate scrap-tire-shreds as an attractive potential alternative to conventional gravel in the drainage layer of leachate collection system by comparative analysis of various physico-chemical parameters. Gravel and scrap-tire-shreds in combination were used as leachate collection layer. Laboratory Test Cells consisting of different combinations of scrap-tire-shreds (size range length = 25.4 mm to 76.1 mm and width = 5 mm) and gravel (size range 10 mm to 20 mm) beds as leachate collection layer with total bed thickness of 500 mm were constructed. Performance study of Test Cells- 1 to 7, having different combinations of scrap-tire-shreds and gravel bed thickness, were studied to work out the best combination. Combined beds of scrap-tire-shreds and gravel gave better results as compared to conventional gravel or scrap- tire- shreds bed when used singly. Test Cell -3 having scrap-tire-shreds layer (200 mm) and gravel layer (300 mm) gave the best results in terms of percentage reduction in various physico-chemical parameters of leachate. The reduction was as high as 68.8 and 79.6% in case of Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) values respectively. Further, three more laboratory Test Cells-8, 9 and 10 were constructed having scrap-tire-shreds and gravel layer ratio same as that of Test Cell- 3 (best combination) but having scrap-tire-shreds of different widths 10 mm, 15 mm and 20 mm to find out the most suitable size. Bed of smaller size scrap-tire-shreds (5 mm) gave better results in comparison to bigger sizes. Leachate sample after passing through combined beds of scrap-tire-shreds and gravel gave better results in percentage reduction in various physico-chemical parameters of leachate as compared to conventional gravel or scrap-tire-shreds bed when used singly.     

FDwave3D: a MATLAB solver for the 3D anisotropic wave equation using the finite-difference method

Seismic modeling plays an important role in geophysics and seismology for estimating the response of seismic sources in a given medium. In this work, we present a MATLAB-based package, FDwave3D, for synthetic wavefield and seismogram modeling in 3D anisotropic media. The seismic simulation is carried out using the finite-difference method over the staggered grid, and it is applicable to both active and passive surveys. The code package allows the incorporation of arbitrary source mechanisms and offers spatial derivative operators of accuracy up to tenth-order along with different types of boundary conditions. First, the methodological aspects of finite-difference method are briefly introduced. Then, the code has been tested and verified against the analytical solutions obtained for the homogeneous model. Further, the numerical examples of layered and overthrust models are presented to demonstrate its reliability.

     

Contamination of sediments in the floodplain wetlands of the lower uMngeni River,Kwa-Zulu Natal,South Africa

This study describes the geochemical and physico-chemical characterization of contaminant status of six wetlands of the lower uMngeni River floodplain, KwaZulu-Natal Province, South Africa. At all sites, organic matter content, calcium carbonate and metal concentrations were highest within the fine-sediment dominated surface laminae, decreasing with depth. Exceptions were displayed by arsenic (As), nickel (Ni) and vanadium (V), presumed to be derived from normal geochemical processes. Geochemical indicies indicated high contamination factors for lead (Pb) and V, pointing to moderate anthropogenic metal pollution contribution. Most conspicuous are the contamination high factors for Pb across most sites. Fe and Pb contamination is ubiquitous in all surface laminae, with contamination factors being either border-line, moderate or of high contamination. Enrichment factors for As, Mn and P at site S6 indicate possible anthropogenic sources. The data also shows a possibility of anthropogenic input of P and Zn at site S3. Apart from the enrichment factors established for Ni across all sites, all other metals indicate some degree of enrichment. A range of variable results for the mid to deeper laminae are indicative of natural processes with some human influence. Results of ANOVA confirm the above. Principal component analysis reveals a 46.4% variance from component 1 elements (Al, Ca, Cr, Cu, Fe, Mg, Mn and Zn) and a 17.8% variance from component 2 (Al, Cu and Fe). Given the rapid rate of development in this region, the protection of these floodplain wetlands must receive high conservation priority from the local municipality.     

The MJO’s impact on rainfall trends over the Congo rainforest

Climate Dynamics - A significant declining trend in rainfall over the Congo basin has been observed over the past three decades. Since the Madden–Julian oscillation (MJO) is a major forcing...     

Global electric circuit parameters and their variability observed over Maitri,Antarctica

The global component of fairweather electricity is subject to special attention to watch the solar-terrestrial effects and secular changes in climate. It is generally considered that the diurnal variation of atmospheric electricity parameters, if they are not following the Carnegie pattern, are not representative of the global thunderstorm activity. Some of the results obtained from Maitri (70°45′54″S, 11°44′03″), are discussed here in context with global thunderstorm activity and space weather influences. The diurnal pattern of the Potential Gradient and current density strongly deviate from the Carnegie curve. We have showed that this deviation is not due to the local electrical influence but due to the global thunderstorm activity. During fairweather condition the parameters are representing the global thunderstorm activity and to some extent they respond to the upper atmospheric electro dynamic phenomenon. The mean value of the potential gradient (77.7 V/m) and current density (2.13 pA/m²) well below the expected global mean but close to the value reported from the same location and season in the past years. The mean conductivity, 3.34 × 10⁻¹⁴ mhom⁻¹, is slightly at higher side and they exhibit a different diurnal trend comparing to the past measurements at this location.     

Evaluation of liquefaction potential hazard of Chennai city, India: using geological and geomorphological characteristics

According to the latest UNFA Report on state of world population 2007, unleashing the potential of urban growth by 2030, the urban population will rise to 5 billion or 60?% of the world population. Liquefaction in urban areas is dangerous phenomenon, which cause more damage to buildings and loss of human lives. Chennai, the capital city of the State Tamil Nadu in India, is one of the densely populated cities in the country. The city has experienced moderate magnitude earthquakes in the past and also categorized under moderate seismic hazard as per the Bureau of Indian Standards (BIS in Criteria for earthquake resistant design of structures; Bureau of Indian Standards, New Delhi, 1893 2001). A study has been carried out to evaluate the liquefaction potential of Chennai city using geological and geomorphological characteristics. The subsurface lithology and geomorphological maps were combined in the GIS platform for assessing the liquefaction potential. The liquefaction hazard broadly classified into three categories viz., liquefaction likely, possible and not likely areas. Mainly, the liquefaction likely areas spread along the coastal areas and around the river beds. The rest of the areas are liquefaction not likely and possible. The present map can be used as first-hand information on regional liquefaction potential for the city, and it will be help to the scientists, engineers and planners who are working for future site-specific studies of the city.     

Empirical assessment of adaptation to climate change impacts of mountain households: development and application of an Adaptation Capability Index

The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors which contribute to successful adaptation and addresses several household functions, such as social networking, livelihood strategy, adjustment strategies, resource availability and accessibility. The proposed Adaptation Capability Index (ACI) is analytically defined, mathematically formulated and field tested on mountainous households in urban and semi-urban regions of the Uttarakhand Himalaya in India. To gather data on the topic relevant to the ACI, a household scale questionnaire was developed and administered to 120 heads of households through face-to-face interviews. The results highlight higher adaptive capability of urban households and low adaptation capacity of rural households due to poor farm productivity, low accessibility and availability of resources and technological input. Future programs and policies must include and implement regulations to remedy attributive factors responsible for higher adaptation. This paper may be applicable to other mountainous regions and may provide insights for effective adaptation strategies to climate change.