SOME PHOTOGRAMMETRIC EXPERIMENTS WITH DIGITAL IMAGE PROCESSING

Recent research involving photogrammetry applied to digital image processing at the Royal Institute of Technology, Stockholm is described. Three particular aspects have been investigated. These concern ground control points for satellite imagery; digital matching of simulated SPOT images; and digital matching of images which have different perspectives. Future prospects of research and development in related topics are outlined.     

Application of remote sensing for vegetation mapping — A case study along the northern coastal districts of andhra pradesh

The study deals with the application of Remote Sensing for delineating various vegetation types along the three coastal districts of Andhra Pradesh. The satellite imagery of the region is divided into three types depending upon tone and texture. Each type is correlated with the ground truth. The species composition has been given and discussed.     

Pre main sequence stars as UV sources for the World Space Observatory-UV mission

Pre-main sequence stars are bright UV (UV) sources compared with their main sequence analogues. The source of this excess is the high energy processes associated with the physics of accretion/outflow during early stellar evolution. In this review, the main sources of UV excess are described as well as the most significant “unknowns” in the field. Special emphasis is made on the results from the last observations carried out with the Hubble Space Telescope and on the relevance of future dedicated monitoring programs with the World Space Observatory-UV.     

Seasonal Cycles,Hypoxia, and Renewal in a Coastal Fjord (Barkley Sound,British Columbia)

The west coast of Vancouver Island (WCVI) is an important marine ecosystem in which concentrations of dissolved oxygen can reach hypoxic levels at certain times of the year. Although the general features of its oceanography are well understood, little is known in particular about the seasonal cycle of oxygen in shelf areas and its interannual variability. It is possible that high temporal resolution monitoring efforts could be carried out relatively easily in sheltered fjords adjacent to the shelf, but the linkages between conditions in these fjords and those on the shelf are also not known. Here a 10-year time series of monthly hydrographic stations in Barkley Sound, British Columbia, is used to identify the seasonal cycle of temperature, salinity, density, dissolved oxygen, and chlorophyll fluorescence in a WCVI fjord. Analysis suggests that there is a standard estuarine circulation in surface and near-surface waters of the Sound, as well as a deep renewal cycle in intermediate and deep waters, and that the two are largely independent. The deep basin in the Sound undergoes annual summer renewals in response to wind-driven upwelling on the shelf, separated by stagnation and hypoxia during fall, winter, and spring downwelling periods. Other than for the stagnant deep waters in winter, residence times in different parts of the Sound are only a few weeks. Barkley Sound characteristics thus adjust rapidly to shelf conditions, and inshore measurements can be used with care as a proxy for some shelf properties. However, phytoplankton biomass does not appear to be affected by the onset of deep renewal and the associated reversal of along-shore winds and instead responds to local factors. Finally, once the seasonal cycle has been accounted for, interannual variations in temperature, density, and dissolved oxygen are uncoupled, possibly in response to longer-term changes in the characteristics of source waters offshore and/or to changes in shelf processes.     

Use of Geomorphological Information in Indirect Landslide Susceptibility Assessment

The objective of this paper is to evaluate the importance of geomorphological expert knowledge in the generation of landslide susceptibility maps, using GIS supported indirect bivariate statistical analysis. For a test area in the Alpago region in Italy a dataset was generated at scale 1:5,000. Detailed geomorphological maps were generated, with legends at different levels of complexity. Other factor maps, that were considered relevant for the assessment of landslide susceptibility, were also collected, such as lithology, structural geology, surficial materials, slope classes, land use, distance from streams, roads and houses. The weights of evidence method was used to generate statistically derived weights for all classes of the factor maps. On the basis of these weights, the most relevant maps were selected for the combination into landslide susceptibility maps. Six different combinations of factor maps were evaluated, with varying geomorphological input. Success rates were used to classify the weight maps into three qualitative landslide susceptibility classes. The resulting six maps were compared with a direct susceptibility map, which was made by direct assignment of susceptibility classes in the field. The analysis indicated that the use of detailed geomorphological information in the bivariate statistical analysis raised the overall accuracy of the final susceptibility map considerably. However, even with the use of a detailed geomorphological factor map, the difference with the separately prepared direct susceptibility map is still significant, due to the generalisations that are inherent to the bivariate statistical analysis technique.     

Water pollution in gold mining industry: a case study in Roşia Montană district, Romania

The preliminary study of streams and rivers from the Roşia Montană area revealed that the concntration of heavy metals— Cd, Mn, Cu, Pb, and Zn—are above accepted limits. The gold extraction method is based on flotation. The most important pollution sources are mine tailings. The determinations were performed for samples collected in: April 2004, July 2004, September 2004, November 2004, February 2005 and May 2005. The highest concentrations were found for cadmium in September 2004: 0.17 mg/L; for copper in September 2004: 1.38 mg/L; for manganese in July 2004: 239.4 mg/L; for lead in May 2005: 0.54 mg/L; and for zinc in September 2004: 35.37 mg/L;. This study involved three small rivers (streams) that flow into the Mureş River and finally into the Danube River, having a great impact on human health and environmental stability in the area. In May 2005, a sample of drinking water from the mining district was also collected.     

Evaluation of Subsurface Lithologic Units for Groundwater Exploration in the Barind Tract of Bangladesh

Barind Tract, located north western part of Bangladesh, is one of the most diversified physiographic units of the country. The surface water supply in this part is particularly limited, so the irrigation is almost entirely depends on groundwater. However, over exploitation indicates falling groundwater heads in this area. The objective of present study is to examine the nature of the aquifer system Barind Tract of Bangladesh in order to assess the sustainability of groundwater yield. Borehole lithology data were collected, processed and analyzed for this purpose. Representative panel diagram, 3-D stratigraphic and cross-sectional views were also prepared for necessary assessment of the variation of individual subsurface stratum in different locations. The study identified three subsurface geologic formations namely, a top clay layer, sand layer of different grain size and at the bottom an impermeable clay zone. Maps of formation thickness and index revealed that aquifer thickness is low in the north-western corner and in some places of middle of south-western corner. The thickness of sand formation in other places is recorded above 20 m. It is expect that the finding of the study will help groundwater resources development, planning and management in the area.     

pH influence on sorption characteristics of heavy metal in the vadose zone

Sorption is an important process in the modelling and prediction of the movement of heavy metals in unsaturated clay barriers. This experimental study investigates the effect of pH changes in the acidic range on the sorption characteristics of heavy metals such as: lead, copper and zinc in an unsaturated soil. A series of one-dimensional coupled solute and moisture leaching column tests, using different heavy metal solutions, were conducted on an unsaturated illitic soil at varying pH values. Variations of volumetric water content (VWC) with distance were measured for different time durations, and concentrations of heavy metals in the liquid and solid phases were analysed. Partitioning coefficient profiles of contaminants along the soil column were determined for each individual layer in the soil.

Results from column leaching tests showed that the sorption characteristics of heavy metals are controlled by many factors which should be taken into consideration, i.e. the VWC, time of wetting, soil pH, and the influent heavy metal concentrations. Simplification of K_d as a constant and of the VWC as a linear function cannot be considered a good assumption and may lead to an improper evaluation of the sorption phenomena and also to serious errors in predicting contaminant transport through unsaturated soils.     

One-atmosphere melting behaviour and nomenclature of terrestrial lavas

On a plot of MgO against one-atmosphere liquidus almost all published data for lavas delineate a single trend, which is fairly well-defined above 1160° C. Segments of this trend form a convenient set of major classificatory subdivisions of lavas. It appears to be hard to justify the use of the term basalt for lavas with less than 6 percent MgO. Even with this restriction, basaltic aphanites occupy a substantial thermal (1150 to 1250° C one-atmosphere liquidi) and chemical (e.g. 6 to 11 percent MgO) range, which might profitably be subdivided. Finally, it is shown that the one-atmosphere liquidus thermal range occupied by the strongly alkalic sodic and potassic lavas is as wide as that covered by the entire set of basaltic volcanic suites from picrites and ankaramites to rhyolites, trachytes and phonolites.Presented at the symposium Recent Advances in the Studies of Rocks and Minerals at High Pressures and Temperatures held in Montreal, 1972. Jointly sponsored by the International Mineralogical Association and the Commission on Experimental Petrology.