Assessment of the environmental impact of Non Point Source (NPS) pollutants on a global, regional and localized scale is the
key component for achieving sustainability of agriculture as well as preserving the environment. The knowledge and information
required to address the problem of assessing the impact of NPS pollutants like Nitrogen (N), Phosphorus (P), etc., on the
environment crosses several sub-disciplines like remote sensing, Geographical Information System (GIS), hydrology and soil
science. The remote sensing data, by virtue of its potential like synopticity, multi-spectral and multi-temporal capability,
computer compatibility, besides providing almost real time information, has enhanced the scope of automation of mapping dynamic
elements, such as land use/land cover, degradation profile and computing the priority categorisation of sub-watersheds. The
present study demonstrates the application of remote sensing, GIS and distributed parameter model Agricultural Non-Point Source
Pollution Model (AGNPS) in the assessment of hazardous non-point source pollution in a watershed. The ARC-INFO GIS and remote
sensing provided the input data to support modelling, while the AGNPS model predicted runoff, sediment and pollutant (N and
P) transport within a watershed. The integrated system is used to evaluate the sediment pollution in about 2700 ha Karso watershed
located in Hazaribagh area of Jharkhand State, India. The predicted values of runoff and sediment yield copared reasonably
well with the measured values. It is important to emphasize that this study is not intended to characterise, in an exhaustive
manner. Instead, the goal is to illustrate the implications and potential advantages of GIS and remote sensing based Hydrology
and Water quality (H/WQ) modelling framework. 相似文献
Development of a spectral library is a prerequisite for the higher order classification of satellite data and hyperspectral image analysis to map any ecosystem with rich diversity. In this study, sampling methodology, collection of field and laboratory spectral signatures and post-processing methodologies were investigated for developing an exclusive spectral library of mangrove species using hyperspectral spectroscopic techniques. Canopy level field spectra and leaf level laboratory spectra were collected for 34 species (25 true and 9 associated mangroves) from two different mangrove ecosystems of the Indian east coast. Post-processing steps such as removal of water vapour absorption bands, correction of drifts which occur due to the thermal properties of the instrument during data collection and smoothing of spectra for its further utilisation were applied on collected spectra. The processed spectra were then compiled as spectral library. 相似文献
The cone-building volcanic activity and subsequent erosion of San Francisco Mountain, AZ, USA, were studied by using high-resolution
digital elevation model (DEM) analysis and new 40Ar/39Ar dating. By defining remnants or planèzes of the volcano flanks in DEM-derived images, the original edifice can be reconstructed.
We propose a two-cone model with adjacent summit vents which were active in different times. The reconstructed cones were
4,460 and 4,350 m high a.s.l., corresponding to ∼2,160 and 2,050 m relative height, respectively. New 40Ar/39Ar data allow us to decipher the chronological details of the cone-building activity. We dated the Older and Younger Andesites
of the volcano that, according to previous mapping, built the stage 2 and stage 3 stratocones, respectively. The new 40Ar/39Ar plateau ages yielded 589–556 ka for the Older and 514–505 ka for the Younger Andesites, supporting their distinct nature
with a possible dormant period between. The obtained ages imply an intense final (≤100 ka long) cone-building activity, terminating
∼100 ka earlier than indicated by previous K-Ar ages. Moreover, 40Ar/39Ar dating constrains the formation of the Inner Basin, an elliptical depression in the center of the volcano initially created
by flank collapse. A 530 ka age (with a ±58.4 ka 2σ error) for a post-depression dacite suggests that the collapse event is
geochronologically indistinguishable from the termination of the andesitic cone-building activity. According to our DEM analysis,
the original cone of San Francisco Mountain had a volume of about 80 km3. Of this volume, ∼7.5 km3 was removed by the flank collapse and subsequent glacial erosion, creating the present-day enlarged Inner Basin, and ∼2 km3 was removed from the outer valleys by erosion. Based on volumetric analysis and previous and new radiometric ages, the average
long-term eruption rate of San Francisco Mountain was ∼0.2 km3/ka, which is a medium rate for long-lived stratovolcanoes. However, according to the new 40Ar/39Ar dates for the last ≤100 ka period, the final stratovolcanic activity was characterized by a greater ∼0.3 km3/ka rate. 相似文献
The Weather Research and Forecasting model has been used to examine the role of land surface processes on Indian summer monsoon simulations. Isolated experiments have been carried out with physical parameterization schemes (land surface and planetary boundary layer) and data assimilation to examine their relative roles in the representation of regional hydroclimate in model simulations. The impact of vegetation green fraction on the model simulations has been extensively studied by replacing the default United States Geological Survey (USGS) vegetation cover data with that of Indian Space Research Organisation (ISRO) data. Results indicate that differences in the treatment of surface processes in the model lead to large differences in precipitation simulation over the Indian domain. Several hydroclimate parameters from the simulations using ISRO and USGS vegetation green fractions were examined. It is seen that the role of vegetation green fraction in these experiments has been to increase latent heat flux to the atmosphere. Two sets of data assimilation experiments were also carried out for an entire year using the same set of observed data but with different land surface parameterization schemes. It is found that evenwhen using the same observed data, the differences in land surface schemes reduce the impact and contribution of observed data being assimilated into the model. The hydroclimate over the region becomes a function of the land surface scheme. This study highlights the importance of vegetation green fraction and land surface schemes in the context of the regional hydroclimate over South Asia. 相似文献
Three specimens of the serranid fish(Serranidae), Plectranthias kamii Randall, 1980 were collected from fish market, Bitung, North Sulawesi on May and June 2010. Some morphological characters P. kamii is closely related to P. sheni, P. megalophthalmus, P. retrofasciatus, P. rubrifasciatus, P. knappi, P. helenae, P. pelicieri, P. jothyi, P.retrofasciatus and P. randalli in sharing of body width, upper jaw length, pelvic spine length and orbit diameter.Meristic count characters of P. kamii differ from P. sheni, P. pilicieri, P. megalophthalmus, P. retrofasciatus and P.rubrifasciatus in having more numerous dorsal spine(18 vs. 15–17) and below lateral line(33–34 vs. 29–33) and differ from P. megalophthalmus and P. rubrifasciatus in having more numerous pored scales in lateral line(13 vs.14–15) and shorter of anal spine. The present anthiine fish collected from Bitung, Indonesia was described as new record and bringing the total number of species of this genus known in Indonesia to seven. 相似文献
The origin and development of erosion-modified, erosion-transformed, and erosion-induced depressions in volcanic terrains
are reviewed and systematized. A proposed classification, addressing terminology issues, considers structural, geomorphic,
and climatic factors that contribute to the topographic modification of summit or flank depressions on volcanoes. Breaching
of a closed crater or caldera generated by volcanic or non-volcanic processes results in an outlet valley. Under climates
with up to ∼2000–2500 mm annual rainfall, craters, and calderas are commonly drained by a single outlet. The outlet valley
can maintain its dominant downcutting position because it quickly enlarges its drainage basin by capturing the area of the
primary depression. Multi-drained volcanic depressions can form if special factors, e.g., high-rate geological processes,
such as faulting or glaciation, suppress fluvial erosion. Normal (fluvial) erosion-modified volcanic depressions the circular
rim of which is derived from the original rim are termed erosion craters or erosion calderas, depending on the pre-existing
depression. The resulting landform should be classed as an erosion-induced volcanic depression if the degradation of a cluster
of craters produces a single-drained, irregular-shaped basin, or if flank erosion results in a quasi-closed depression. Under
humid climates, craters and calderas degrade at a faster rate. Mostly at subtropical and tropical ocean-island and island-arc
volcanoes, their erosion results in so-called amphitheater valleys that develop under heavy rainfall (>∼2500 mm/year), rainstorms,
and high-elevation differences. Structural and lithological control, and groundwater in ocean islands, may in turn preform
and guide development of high-energy valleys through rockfalls, landsliding, mudflows, and mass wasting. Given the intense
erosion, amphitheater valleys are able to breach a primary depression from several directions and degrade the summit region
at a high rate. Occasionally, amphitheater valleys may create summit depressions without a pre-existing crater or caldera.
The resulting, negative landforms, which may drain in several directions and the primary origin of which is commonly unrecognizable,
should be included in erosion-transformed volcanic depressions.
Received: 4 January 1998 / Accepted: 18 January 1999 相似文献
Any sustainable resource utilization plan requires evaluation of the present and future environmental impact. The present research focuses on future scenario generation of environmental vulnerability zones based on grey analytic hierarchy process (grey-AHP). Grey-AHP combines the advantages of grey clustering method and the classical analytic hierarchy process (AHP). Environmental vulnerability index (EVI) considers twenty-five natural, environmental and anthropogenic parameters, e.g. soil, geology, aspect, elevation, slope, rainfall, maximum and minimum temperature, normalized difference vegetation index, drainage density, groundwater recharge, groundwater level, groundwater potential, water yield, evapotranspiration, land use/land cover, soil moisture, sediment yield, water stress, water quality, storage capacity, land suitability, population density, road density and normalized difference built-up index. Nine futuristic parameters were used for EVI calculation from the Dynamic Conversion of Land-Use and its Effects, Model for Interdisciplinary Research on Climate 5 and Soil and Water Assessment Tool. The resulting maps were classified into three classes: “high”, “moderate” and “low”. The result shows that the upstream portion of the river basin comes under the high vulnerability zone for the years 2010 and 2030, 2050. The effectiveness of zonation approach was between “better” and “common” classes. Sensitivity analysis was performed for EVI. Field-based soil moisture point data were utilized for validation purpose. The resulting maps provide a guideline for planning of detailed hydrogeological studies.