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41.
Validation is a necessary step for model acceptance and is defined as a comparison of the model’s predictions with real world
to determine whether the model is suitable for its intended purpose. We have validated the biological richness index for three
states generated in ‘Biodiversity Characterization at Landscape Level’ project under the aegis of Department of Biotechnology
and Department of Space of the Government of India. Biological Richness (BR) index, described elsewhere as a cumulative property
of ecological habitats and surroundings; was analyzed as an integrated ‘threetier modeling approach’ of (i) utilization of
geospatial tools, (ii) limited field survey and (iii) landscape analysis. 相似文献
42.
M. D. Behera 《Journal of the Indian Society of Remote Sensing》2010,38(3):465-475
Tropical forest fragmentation has been a major concern towards biodiversity conservation. Indices to determine the community
structure and their relationship with forest fragmentation have been a matter of investigation. Here, I investigated the plant
diversity across a fragmentation gradient in a typical human-influenced forested landscape in eastern Himalaya. The stratification
for guiding field sampling was done using satellite remote sensing derived forest type map at 1:50,000 scale. The results
of 49 sample plots (nested quadrant of 20×20 m size) following stratified random sampling method were analysed. It was observed
that high fragmented forests have fewer plant species, reduced anthropogenic use evidence and newer community types than medium
and low fragment forests. In general, species diversity and species dominance were observed to be inversely proportional and
directly proportional to forest fragmentation. Basal area followed a decreasing trend along fragmentation gradient. These
results revealed that higher level of fragmentation permits low diversity in the eastern Himalayan tropical forests. 相似文献
43.
Sorptive removal of ibuprofen from water using selected soil minerals and activated carbon 总被引：1，自引：1，他引：0
S. K. Behera S. Y. Oh H. S. Park 《International Journal of Environmental Science and Technology》2012,9(1):85-94
Pharmaceuticals have gained significant attention in recent years due to the environmental risks posed by their versatile application and occurrence in the natural aquatic environment. The transportation and distribution of pharmaceuticals in the environmental media mainly depends on their sorption behavior in soils, sediment?Cwater systems and waste water treatment plants, which varies widely across pharmaceuticals. Sorption of ibuprofen, a non-steroidal anti-inflammatory drug, onto various soil minerals, viz., kaolinite, montmorillonite, goethite, and activated carbon, as a function of pH (3?C11), ionic strength (NaCl concentration: 0.001?C0.5?M), and the humic acid concentration (0?C1,000?mg/L) was investigated through batch experiments. Experimental results showed that the sorption of ibuprofen onto all sorbents was highest at pH 3, with highest sorption capacity for activated carbon (28.5?mg/g). Among the minerals, montmorillonite sorbed more ibuprofen than kaolinite and goethite, with sorption capacity increasing in the order goethite (2.2?mg/g)?<?kaolinite (3.1?mg/g)?<?montmorillonite (6.1?mg/g). The sorption capacity of the selected minerals increased with increase in ionic strength of the solution in acidic pH condition indicating that the effect of pH was predominant compared to that of ionic strength. An increase in humic acid concentration from low to high values made the sorption phenomena very complex in the soil minerals. Based on the experimental observations, montmorillonite, among the selected soil minerals, could serve as a good candidate to remove high concentrations of ibuprofen from aqueous solution. 相似文献
44.
K. Rajkumar A. L. Ramanathan P. N. Behera 《Journal of the Geological Society of India》2012,80(3):429-434
Clay minerals, byproducts of chemical weathering, are important group of minerals found in rivers, estuaries, and marine sedimentary environments, which include mudstones, clay stones, and shales. In the present study, FTIR and SEM investigation on the clay minerals in Sundarban mangrove core sediments collected from Moipith Matla and Belamati Island are carried out. The study indicated the dominant association of kaolinite with subordinate amount of quartz, illite and chlorite. The abundance of kaolinite, illite chlorite and clay with quartz helps in increasing sediment in the islands region. The geochemical and mineralogical evolution of mangrove sediments are results of the interaction of biotic and abiotic parameters, whose balance is conditioned by the climate that governs the hydrologic regime, the sedimentation dynamics and the organic matter. This study on the charaterstation of clay provides us with substantial impact in the water holding capacity, productivity and mineralogical and chemical transformation in order to establish much more and intermediate equilibrium between marine influence and continental contribution, as part of the estuarine environment, than to the tropical climate conditions. 相似文献
45.
Swadhin Behera Jayanthi V. Ratnam Yukio Masumoto Toshio Yamagata 《Climate Dynamics》2013,41(3-4):663-676
Extreme summers of Europe are usually affected by blocking highs that shift between Western and Eastern Europe to cause regional variations in the surface temperature anomalies. Generally, the blocking high induces a regional temperature dipole with poles of warm and cold anomalies on two sides of Europe. The extreme summers of Western Europe, when the Eastern Europe is colder than normal, are usually associated with the teleconnections arising from positive Indian Ocean Dipole (IOD) events. In contrast, analogous warm events in Eastern Europe are usually associated with La Niña. The western Pacific conditions that prevail during the turnaround phase of El Niño to La Niña are found to be responsible for developing the extreme Eastern Europe events. The role of North Atlantic Oscillation (NAO) is not blatant for the Eastern Europe summers though it has a weaker influence on Western Europe summers for which IOD plays a dominant role: The seasonal July–August correlation for Western Europe temperature with IOD index is higher than that with the NAO index. The teleconnections for both types of extremes are associated with a Rossby wavetrain that travel around the globe to reach the Europe. This circumglobal teleconnection is largely determined by the location of the tropospheric heat source. For Western Europe warm events, major contributions come from the atmospheric convections/diabatic heating over northwest India and southern Pakistan. For the Eastern Europe events, the convections over northwest Pacific, south of Japan, are found to project the signals on to the mid-latitude wave-guide. These patterns of teleconnection are so robust that those can be seen on daily to seasonal time-scales of atmospheric anomalies. The wavetrains are found to set-in a couple of weeks prior to the development of blocking highs and extreme hot conditions over Europe. 相似文献
46.
K. Rajkumar AL. Ramanathan P. N. Behera S. Chidambaram 《Arabian Journal of Geosciences》2014,7(2):537-544
Clay mineral found in rivers, estuaries, and marine sedimentary environments is an important group of minerals which is the by-product of chemical weathering. The main constituents of this fine-grained sediment include mudstones, clay stones, and shales. This is probably the first report of a Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) investigation on the clay minerals to characterize them in the Sundarban mangrove core sediments of Moipith Matla and Belamati Island. This study was carried out in the selected stretch for FTIR and SEM analyses. The study reveals the dominant association of kaolinite with subordinate amount of quartz, illite, and chlorite. The abundance of kaolinite, illite, chlorite, and clay with quartz helps in increasing the sediment in the island region. The geochemical and mineralogical evolution of mangrove sediment results in the interaction of biotic and abiotic parameters, whose balance is conditioned by the climate that governs the hydrologic regime, the sedimentation dynamics, and of the organic matter. This study on the characterization of clay provides substantial impact in the water-holding capacity, productivity, and mineralogical and chemical transformation in order to establish much more and intermediate equilibrium between marine influence and continental contribution, as a part of the estuarine environment. 相似文献
47.
Anisotropic Bianchi-III cosmological model is investigated with variable gravitational and cosmological constants in the framework of Einstein’s general relativity. The shear scalar is considered to be proportional to the expansion scalar. The dynamics of the anisotropic universe with variable G and Λ are discussed. Without assuming any specific forms for Λ and the metric potentials, we have tried to extract the time variation of G and Λ from the anisotropic model. The extracted G and Λ are in conformity with the present day observations. Basing upon the observational limits, the behavior and range of the effective equation of state parameter are discussed. 相似文献
48.
Desmond Manatsa Barnabas Chipindu Swadhin K. Behera 《Theoretical and Applied Climatology》2012,110(1-2):115-128
The decadal shift in the relationship between the Indian Ocean Dipole (IOD) and the East African rainfall is investigated using historical observational data. The climate system for equatorial East Africa (EEA) during the October to December (OND) ‘short rains’ season is characterised by spatiotemporal variations of the equatorial East African rainfall (EEAR). Therefore, the EEAR index is derived from the first principal component of the empirical orthogonal function analysis (EOF) of the EEA’s rainfall domain. The IOD, which has been linked with the EEAR in the previous studies, is the main climate mode controlling the tropical Indian Ocean during the OND period. It is usually represented by a dipole mode index based on the zonal gradient of SST anomalies in the tropical Indian Ocean. Therefore the climate modes, IOD and EEAR, are assumed to form a two-node network of subsystems which primarily control the climate of equatorial East Africa during the OND period. The collective behaviour of these climate modes is investigated through the examination of their representative indices for the period 1901 to 2009 using simple statistical techniques. The results suggest that the interaction between these two climate modes, which comprise the network, is not predominantly linear as previously assumed, but is characterised by shifts which are determined by the coupling and synchronisation processes of the tropical systems. In cases where synchronisation is preceded by an abrupt increase in coupling strength between the two subsystems, the established synchronous state is destroyed and a new climate state emerges such as in the years 1961 and 1997. This alteration in the regional climate is accompanied by notable changes in the regional rainfall and IOD variations. But in those events where synchronisation is followed by a sudden loss in coupling strength, the climate state is not disturbed and no shift in the climate of equatorial East Africa is noticed as in 1918. This climate shift mechanism appears to be consistent with the theory of synchronised chaos and is useful for long range predictions of the East African short rains. 相似文献
49.
Anomalous winter climate conditions in the Pacific rim during recent El Niño Modoki and El Niño events 总被引：2，自引：1，他引：1
Present work compares impacts of El Niño Modoki and El Niño on anomalous climate in the Pacific rim during boreal winters of 1979–2005. El Niño Modoki (El Niño) is associated with tripole (dipole) patterns in anomalies of sea-surface temperature, precipitation, and upper-level divergent wind in the tropical Pacific, which are related to multiple “boomerangs” of ocean-atmosphere conditions in the Pacific. Zonal and meridional extents of those “boomerangs” reflect their independent influences, which are seen from lower latitudes in the west to higher latitudes in the east. In the central Pacific, more moisture is transported from the tropics to higher latitudes during El Niño Modoki owing to displacement of the wet “boomerang” arms more poleward toward east. Discontinuities at outer “boomerang” arms manifest intense interactions between tropical and subtropical/extratropical systems. The Pacific/North American pattern and related climate anomalies in North America found in earlier studies are modified in very different ways by the two phenomena. The seesaw with the dry north and the wet south in the western USA is more likely to occur during El Niño Modoki, while much of the western USA is wet during El Niño. The moisture to the southwestern USA is transported from the northward shifted ITCZ during El Niño Modoki, while it is carried by the storms traveling along the southerly shifted polar front jet during El Niño. The East Asian winter monsoon related anticyclone is over the South China Sea during El Niño Modoki as compared to its position over the Philippine Sea during El Niño, causing opposite precipitation anomalies in the southern East Asia between the two phenomena. 相似文献
50.
Pallavi Behera K. H. V. Durga Rao K. K. Das 《Journal of the Indian Society of Remote Sensing》2005,33(1):165-176
Hardly any part of the world has remained unchanged since the arrival of the speciesHomo sapiens including the mountain ecosystems. Himalayan physiographic unit of India in due course has become populated and is tolerating
all kinds of human interventions. Soil erosion in this region has been identified as a major problem due to both natural and
anthropogenic factors. Remote sensing and Geographical Information system (GIS) techniques hold great promises in the assessment
and conservation of natural resources including the surface soil. The major objective of the present study was to apply a
process based model to quantify soil erosion and to prioritize the sub-watershed on this basis. The sub-watershed located
at Jakhan rao area of Western Dun in lower Himalayan belt was taken as the test site for the study at 1: 50,000 scale. Deforestation,
unscientific agricultural practices, terrace farming, cattle grazing and land degradation in the sub-watershed are some of
the anthropogenic factors causing soil erosion in the area. Here, MMF model was used for estimation of soil erosion by incorporating
layers derived from both remote sensing and ancillary data. IRS 1C LISS III satellite data was used for the preparation of
land use map that was used to derive RD map, BD map and K map. Digital Elevation Model (DEM) provided slope map, an intermediate
layer used in equation 6 to generate G map, and soil map provided MS map, BD map and K map. The above intermediate layers
generated were then integrated in GIS domain to estimate the amount of soil erosion in the sub-watershed area. Results show
high values 4572.333 kg/m2 for G map, which depicted transport capacity of overland flow. Comparatively lower values 13.15, and 7.98 kg/m2were observed for F map, which depicted soil detachment by raindrop impact. The subtracted image of the aforesaid layers produced
the real picture, where in the highest value 3.770 kg/m2 was found in the midland region of the site. The crossed erosion map was then classified into different erosion classes for
sub-watershed area. This study illustrates the applications of remote sensing and GIS techniques for soil erosion modeling. 相似文献