Monitoring turbid freshwater plume characteristics by means of remotely sensed data     

Sinasi Kaya  Dursun Z. Seker  Sedat Kabdasli  Nebiye Musaoglu  Akira Yuasa  Madhusudan B. Shrestha 《水文研究》2006,20(11):2429-2440

Remotely sensed data may provide easy access for monitoring the spatial separation and obtaining the hydrodynamic characteristics of turbid freshwater plumes created by river flow in the marine environment. Traditional methods are time consuming and require great effort to produce sufficient data. In this project, integrated research has been carried out on a river to demonstrate the utility of remote sensing (RS) technology for studying fundamental theoretical properties of turbulent mixtures. The Filyos River mouth, located on the Black Sea coast of Turkey, is the research area. Flow properties, such as the horizontal dispersion coefficient, have been calculated (using Landsat TM sensor images taken on two different dates). The effects of the plume on the morphology of neighbouring beaches are also examined. This study shows the utility of RS technology for generating quantitative data and better defining the hydraulic behaviour of a river with high turbidity. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

A new scenario framework for Climate Change Research: scenario matrix architecture   总被引：2，自引：2，他引：0  

Detlef P. van Vuuren  Elmar Kriegler  Brian C. O’Neill  Kristie L. Ebi  Keywan Riahi  Timothy R. Carter  Jae Edmonds  Stephane Hallegatte  Tom Kram  Ritu Mathur  Harald Winkler 《Climatic change》2014,122(3):373-386

This paper describes the scenario matrix architecture that underlies a framework for developing new scenarios for climate change research. The matrix architecture facilitates addressing key questions related to current climate research and policy-making: identifying the effectiveness of different adaptation and mitigation strategies (in terms of their costs, risks and other consequences) and the possible trade-offs and synergies. The two main axes of the matrix are: 1) the level of radiative forcing of the climate system (as characterised by the representative concentration pathways) and 2) a set of alternative plausible trajectories of future global development (described as shared socio-economic pathways). The matrix can be used to guide scenario development at different scales. It can also be used as a heuristic tool for classifying new and existing scenarios for assessment. Key elements of the architecture, in particular the shared socio-economic pathways and shared policy assumptions (devices for incorporating explicit mitigation and adaptation policies), are elaborated in other papers in this special issue.  相似文献   

Livelihood diversification as an adaptation approach to change in the pastoral Hindu-Kush Himalayan region   总被引：1，自引：0，他引：1  

Ning Wu  Muhammad Ismail  Srijana Joshi  Shao-liang Yi  Ritu Meher Shrestha  Abdul Wahid Jasra 《山地科学学报》2014,11(5):1342-1355

Migratory livestock raising has been one of the most important livelihood options for people residing in high mountain areas and has made a significant contribution to the economy of the Hindu Kush Himalayan（HKH） region, both in terms of supporting households and in export earnings. However, in recent decades, changes in the socioeconomic situation and increasing climate variability have led to a need to enhance adaptation by building the resilience of local socio-ecological systems, including economic diversification and sustainable management of natural resources. Based on semistructured interviews with pastoral communities in six countries within the pastoral HKH region, this paper discusses the situation, trends and driving forces behind the diversification of pastoral livelihood. For internal diversification the study highlights the need for enhancement of pastoral livelihoods through value-adding activities in the pastoral sectors. For external diversification changes on policy changes are needed to support free out-migration, market exploitation, and multiple resource use. Finally the paper highlights the role of education in determining household adaptation strategies in the face of various socio-ecological pressures and recommends integrating innovative and indigenous knowledge to develop appropriate methods for risk management and resource management in the pastoral HKH region.  相似文献   

Mesozoic to Cenozoic tectono‐metamorphic history of the South Pamir–Hindu Kush (Chitral,NW Pakistan): Insights from phase equilibria modelling,and garnet–monazite petrochronology     

Mathieu Soret  Kyle P. Larson  John M. Cottle  Matthijs Smit  Alex Johnson  Sudip Shrestha  Asghar Ali  Shah Faisal 《Journal of Metamorphic Geology》2019,37(5):633-666

The Karakoram–Hindu Kush–Pamir and adjacent Tibetan plateau belt comprise a series of Gondwana‐derived crustal fragments that successively accreted to the Eurasian margin in the Mesozoic as the result of the progressive Tethys ocean closure. These domains provide unique insights into the thermal and structural history of the Mesozoic to Cenozoic Eurasian plate margin, which are critical to inform the initial boundary conditions (e.g. crustal thickness, structure and thermo‐mechanical properties) for the subsequent development of the large and hot Tibetan–Himalaya orogen, and the associated crustal deformation processes. Using a combination of microstructural analyses, thermobarometry modelling and U–Th–Pb monazite and Lu–Hf garnet geochronology, the study reappraises the metamorphic history of exposed mid‐crustal metapelites in the Chitral region of the South Pamir–Hindu Kush (NW Pakistan). This study also demonstrates that trace elements in monazite (especially Y and Dy), combined with thermodynamical modelling and Lu–Hf garnet dating, provides a powerful integrated toolbox for constraining long‐lived and polyphased tectono‐metamorphic histories in all their spatial and temporal complexity. Rocks from the Chitral region were progressively deformed and metamorphosed at sub‐ and supra‐solidus conditions through at least four distinct episodes from the Mesozoic to the Cenozoic. Rocks were first metamorphosed at ~400–500°C and ~0.3 GPa in the Late Triassic–Early Jurassic (210–185 Ma), likely in response to the accretion of the Karakoram during the Cimmerian orogeny. Pressure and temperature subsequently increased by ~0.3 GPa and 100°C in the Early‐ to Mid Cretaceous (140–80 Ma), coinciding with the intrusion of calcalkaline granitic plutons across the Karakoram and Pamir regions. This event is interpreted as the record of crustal thickening and the development of a proto‐plateau within the Eurasian margin due to a long‐lived episode of slab flattening in an Andean‐type margin. Peak metamorphism was reached in the Late Eocene–Early Oligocene (40–30 Ma) at conditions of 580–600°C and ~0.6 GPa and 700–750°C and 0.7–0.8 GPa for the investigated staurolite schists and sillimanite migmatites respectively. This crustal heating up to moderate anatexis likely resulted in the underthrusting of the Indian plate after a NeoTethyan slab‐break off or to the Tethyan Himalaya–Lhasa microcontinent collision and subsequent oceanic slab flattening. Near‐isothermal decompression/exhumation followed in the Late Oligocene (28–23 Ma) as marked by a pressure decrease in excess of ~0.1 GPa. This event was coeval with the intrusion of the 24 Ma Garam Chasma leucogranite. This rapid exhumation is interpreted to be related to the reactivation of the South Pamir–Karakoram suture zone during the ongoing collision with India. The findings of this study confirm that significant crustal shortening and thickening of the south Eurasian margin occurred during the Mesozoic in an accretionary‐type tectonic setting through successive episodes of terrane accretions and probably slab flattening, transiently increasing the coupling at the plate interface. Moreover, they indicate that the south Eurasian margin was already hot and thickened prior to Cenozoic collision with India, which has important implications for orogen‐scale strain‐accommodation mechanisms.  相似文献   

Distribution patterns of medicinal plants along an elevational gradient in central Himalaya, Nepal   总被引：1，自引：1，他引：0  

Maan B.ROKAYA  Zuzana MNZBERGOVá  Mani R.SHRESTHA  Binu TIMSINA 《山地科学学报》2012,9(2):201-213

This study aimed to compare the distribution patterns and trends of plant parts used among different groups of medicinal plants, geographical regions,and between medicinal plants and all vascular plants.We used the published sources for elevation records of 2,331 medicinal plant species to interpolate presence between minimum and maximum elevations and estimated medicinal plant richness for each 100-m elevational band. Monte Carlo simulations were used to test whether differences in elevational distribution between different groups of medicinal plants were significant. Total number of medicinal plants as well as different groups showed unimodal relationship with elevation. The elevational distributions of medicinal plants significantly differ between regions and between medicinal plant groups.When comparing the richness of all medicinal plants to all vascular plants,Monte Carlo simulations indicated that the numbers of medicinal plants are higher than expected at low elevations.The highest richness of medicinal plants at low elevation could be possibly due to favorable environmental factors such as high temperature, rainfall,sunlight or due to higher density of human population and thus higher pressure on use of any plants in lower elevations.  相似文献   

Mitigation of Iron Toxicity and Iron,Zinc, and Manganese Nutrition of Wetland Rice Cultivars (Oryza sativa L.) Grown in Iron‐Toxic Soil          下载免费PDF全文

Mohammad Shahid  Amaresh Kumar Nayak  Arvind Kumar Shukla  Rahul Tripathi  Anjani Kumar  Rajagounder Raja  Bipin Bihari Panda  Jitendriya Meher  Pratap Bhattacharyya  Debiprasad Dash 《洁净——土壤、空气、水》2014,42(11):1604-1609

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Antibiotic Pollution in the Environment: A Review   总被引：1，自引：0，他引：1       下载免费PDF全文

Ritu Gothwal  Thhatikkonda Shashidhar 《洁净——土壤、空气、水》2015,43(4):479-489

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Predicting the impact of climate change on the distribution of two threatened Himalayan medicinal plants of Liliaceae in Nepal     

Santosh Kumar Rana  Hum Kala Rana  Suresh Kumar Ghimire  Krishna Kumar Shrestha  Sailesh Ranjitkar 《山地科学学报》2017,14(3):558-570

Predicting the potential distribution of medicinal plants in response to climate change is essential for their conservation and management. Contributing to the management program, this study aimed to predict the distribution of two threatened medicinal plants, Fritillaria cirrhosa and Lilium nepalense. The location of focal species gathered from herbarium specimen housed in different herbaria and online databases were geo-referenced and checked for spatial autocorrelation. The predictive environmental variables were selected, and MaxEnt software was used to model the current and future distributions of focal species. Four Representative Concentration Pathway (RCP) trajectories of the BCC-CSM1.1 model were used as the future (2050) projection layer. The MaxEnt modelling delineated the potential distribution of F. cirrhosa and L. nepalense. The current suitability is projected towards Central and Eastern Hilly/Mountainous regions. Both species gain maximum suitability in RCP 4.5 which decline towards other trajectories for L. nepalense. Overall, both the focal species shift towards the north-west, losing their potential habitat in hilly and lower mountainous regions by 2050 across all trajectories. Our results highlight the impact of future climate change on two threatened and valuable species. The results can be further useful to initiate farming of these medicinally and economically important species based on climatically suitable zone and for designing a germplasm conservation strategy.  相似文献   

Topography and human disturbances are major controlling factors in treeline pattern at Barun and Manang area in the Nepal Himalaya     

Parveen K. Chhetri  Krishna B. Shrestha  David M. Cairns 《山地科学学报》2017,14(1):119-127

The alpine treeline ecotone is an important component of mountain ecosystems of the Nepal Himalaya; it plays a vital role in the livelihood of indigenous people, and provides ecosystem services. However, the region faces a problem of paucity of data on treeline characteristics at the regional and landscape scales. Therefore, we used Remote Sensing (RS), and Geographic Information Science (GIS) approaches to investigate cross-scale interactions in the treeline ecotone. Additionally, European Space Agency land cover map, International Center for Integrated Mountain Development (ICIMOD) land cover map, ecological map of Nepal, and United States Geological Survey Shuttle Radar Topography Mission-Digital Elevation Model were used to analyze treeline pattern at the regional scale. Digital Globe high-resolution satellite imagery of Barun (eastern Nepal) and Manang (central Nepal) were used to study treeline patterns at the landscape scale. Treeline elevation ranges from 3300-4300 m above sea level. Abies spectabilis, Betula utilis, and Pinus wallichiana are the main treeline-forming species in the Nepal Himalaya. There is an east to west treeline elevation gradient at the regional scale. No slope exposure is observed at the regional scale; however, at the landscape scale, slope exposure is present only in a disturbed area (Manang). Topography and human disturbance are the main treeline controlling factor in Barun and Manang respectively.  相似文献   

Performance evaluation of a ground-source heat pump system utilizing a flowing well and estimation of suitable areas for its installation in Aizu Basin,Japan     

Gaurav Shrestha  Youhei Uchida  Satoru Kuronuma  Mutsumi Yamaya  Masahiko Katsuragi  Shohei Kaneko  Naoaki Shibasaki  Mayumi Yoshioka 《Hydrogeology Journal》2017,25(5):1437-1450

Development of a ground-source heat pump (GSHP) system with higher efficiency, and evaluation of its operating performance, is essential to expand the growth of GSHP systems in Japan. A closed-loop GSHP system was constructed utilizing a flowing (artesian) well as a ground heat exchanger (GHE). The system was demonstrated for space-heating and space-cooling of a room (area 126.7 m²) in an office building. The average coefficient of performance was found to be 4.5 for space-heating and 8.1 for space-cooling. The maximum heat exchange rate was 70.8 W/m for space-heating and 57.6 W/m for space-cooling. From these results, it was determined that a GSHP system with a flowing well as a GHE can result in higher performance. With this kind of highly efficient system, energy saving and cost reduction can be expected. In order to assess appropriate locations for the installation of similar kinds of GSHP systems in Aizu Basin, a suitability map showing the distribution of groundwater up-flowing areas was prepared based on the results of a regional-scale three-dimensional analytical model. Groundwater up-flowing areas are considered to be suitable because the flowing well can be constructed at these areas. Performance evaluation of the GSHP system utilizing the flowing well, in conjunction with the prepared suitability map for its installation, can assist in the promotion of GSHP systems in Japan.  相似文献