Mountain erosion and mitigation: global state of art     

Anjan Patel 《Environmental Earth Sciences》2012,66(6):1631-1639

Mountain erosion mapping is one of the important aspects for monitoring environmental degradation. Global climate change coupled with human activities is eroding the mountain regions of the world at an alarming rate. The various types of erosion can be classified as water erosion, aeolian erosion, glaciered erosion, gravity erosion and man-made erosion. Tectonic activity also plays a major role towards mountain erosion. Soil erosion along with debris flow and rock falling not only causes loss of human life and property, but also affects the climatic condition of the mountain regions. Mountain erosion mitigation and protection methods include wire mesh fencing with inclusion of brush layers and brush mats on fascines, constructing check dams and slope benches and application of bioengineering works such as plantation and vegetation growth. This study consists of the global scenario with some of the state-of-the-art methods for mitigation and mappings of mountain erosion. The erosion in mountainous regions can be controlled with the help of suitable vegetation and plant growth, with installation of special bioengineered materials. However, public awareness is also considered as an important factor. Moreover, it is found that mapping the rate of erosion greatly helps to make proper action plan against the erosion process.  相似文献   

Trace fossil assemblages in mixed siliciclastic-carbonate sediments of the Kaladongar Formation (Middle Jurassic), Patcham Island,Kachchh, Western India     

Jaquilin?K.?JosephEmail author  Satish?J.?Patel  Nishith?Y.?Bhatt 《Journal of the Geological Society of India》2012,80(2):189-214

The Middle Jurassic rocks of the Kaladongar Formation well exposed in the Kaladongar Hill range of the Patcham Island and Kuar Bet of the Northern Kachchh comprises of ∼450 m thick sequence of mixed siliciclasticcarbonate sediments intercalated with shales. These Mixed siliciclastic-carbonate sediments show wide variation in textural and mineralogical composition and represent genetically related six rock types: micritic sandstone, allochemic sandstone, sandy allochemic limestone, micrtic mudrock, sandy micrite and muddy micrite; which are highly bioturbated and show behaviourally diverse groups of trace fossils. Total 34 ichnogenera are identified, which includes, Arenicolites, Asterosoma, Beaconites, Bergaueria, Chondrites, Cochlichnus, Dactylophycus, Daedalus, Didymaulichnus, Diplocraterion, Gordia, Gyrochorte, Gyrolithes, Ichnocumulus, Laevicyclus, Lockeia, Margaritichnus, Monocraterion, Nereites, Ophiomorpha, Palaeophycus, Phoebichnus, Phycodes, Pilichnus, Planolites, Plug Shaped Form, Protovirgularia, Rhizocorallium, Scolicia, Skolithos, Taenidium, Teichichnus, Thalassinoides and Walcottia. These trace fossils are classified into six morphological groups namely, circular and elliptical structures; simple structures; branched structures; rosette structures; spreiten structures; and winding and meandering structures. These trace fossils are further group into eight assemblages which occurred together into mixed siliciclastic-carbonate sediments, include, Asterosoma assemblage, Gyrochorte assemblage, Rhizocorallium assemblage, Thalassinoides assemblage, Planolites-Palaeophycus assemblage, Phycodes assemblage, Ophiomorpha assemblage and Skolithos assemblage. The recurring pattern of these assemblages through the sequence displays the development of Skolithos and Cruziana ichnofacies and at places the mixed Skolithos-Cruziana ichnofacies which suggest a low wave and current energy conditions with intervening period of high wave and current energy conditions and an intermediate period of stressful environments, respectively. Sedimentological and ichnological data suggest that the deposition of the mixed siliciclastic-carbonate sediments of the Kaladongar Formation took place in the foreshore to offshore environment under fluctuating wave and current energy condition.  相似文献   

A comparison of metallic contents in lichen Pyxine subcinerea, its substratum and soil     

V. Shukla  D. K. Patel  D. K. Upreti  M. Yunus  S. Prasad 《International Journal of Environmental Science and Technology》2013,10(1):37-46

Chromium, copper, cadmium, lead, nickel, iron and zinc contents of a lichen species (Pyxine subcinerea Stirton) and mango bark collected from 12 sites in Haridwar city (Uttarakhand) were compared with soil, sampled from beneath the tree from which lichens were collected. The metal contents in lichen, bark and soil ranged from 1,573 to 18,793, 256 to 590 and 684 to 801 μg g^?1, respectively. This clearly indicates that lichens accumulated higher amounts of metal compared to bark or soil. Statistical analysis revealed that metal concentration in lichens did not show significant linear correlation with the bark or soil. Pearsons correlation coefficients revealed negative correlation of Pb (r = ?0.2245) and Ni (r = ?0.0480) content between lichen and soil, which indicate direct atmospheric input of metals from ambient environment. Quantification and comparison of elemental concentration in lichens, its substratum and soil can provide valuable information about air quality in the collection area.  相似文献   

Application of frequency ratio and likelihood ratio model for geo-spatial modelling of landslide hazard vulnerability assessment and zonation: a case study from the Sikkim Himalayas in India     

L.P. Sharma  Nilanchal Patel  M.K. Ghose  P. Debnath 《国际地球制图》2013,28(2):128-146

The Likelihood Ratio (LR) Model has been applied as an improvement upon the Frequency Ratio (FR) that computes the ratio of the percentage of the landslide pixels to the percentage of the non-landslide pixels instead of the total number of pixels used in the denominator as in case of the FR. The comparative assessment of the two techniques is made through spatial modelling of GIS vector data using the ArcGIS software. Two different Landslide Information Values were computed for each polygon element of the study area employing the two FR techniques that categorized the study area into five classes of vulnerability using natural breaks (Jenks) technique. Subsequently, vulnerability zonation maps were prepared showing the different levels of landslide vulnerability. The LR technique yielded significantly higher vulnerability assessment accuracy (77%) as compared to the standard FR (71%).  相似文献   

Populations of supersoft X‐ray sources: Novae,tidal disruption,Type Ia supernovae,accretion‐induced collapse,ionization, and intermediatemass black holes?     

R. Di Stefano  F.A. Primini  J. Liu  A. Kong  B. Patel 《Astronomische Nachrichten》2010,331(2):205-211

Observations of hundreds of supersoft X‐ray sources (SSSs) in external galaxies have shed light on the diversity of the class and on the natures of the sources. SSSs are linked to the physics of Type Ia supernovae and accretion‐induced collapse, ultraluminous X‐ray sources and black holes, the ionization of the interstellar medium, and tidal disruption by supermassive black holes. The class of SSSs has an extension to higher luminosities: ultraluminous SSSs have luminosities above 10³⁹ erg s^–1. There is also an extension to higher energies: quasisoft X‐ray sources (QSSs) emit photons with energies above 1 keV, but few or none with energies above 2 keV. Finally, a significant fraction of the SSSs found in external galaxies switch states between observations, becoming either quasisoft or hard. For many systems “supersoft” refers to a temporary state; SSSs are sources, possibly including a variety of fundamentally different system types, that pass through such a state. We review those results derived from extragalactic data and related theoretical work that are most surprising and that suggest directions for future research (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Improvement in Precision of Crop Acreage Estimation by Remote Sensing Using Frequency Distribution Based Stratification     

Nita?BhagiaEmail author  D.?R.?Rajak  N.?K.?Patel 《Journal of the Indian Society of Remote Sensing》2011,39(2):153-160

A study was conducted to improve precision of crop acreage adopting stratified random sampling approach. Remotely sensed data was used to classify mustard crop for the states of Rajasthan, Madhya Pradesh, Uttar Pradesh, Gujarat and Haryana covering 81% of mustard area of India. A grid of size 5 × 5 km was super-imposed on classified image of study area and proportion of mustard crop within the grid was ascertained. Crop proportion was used to determine strata. Stratification was done based on equal interval of proportion, equal sample number and cumulative square root of frequency method. Cumulative square root of frequency method gave highest precision in all the cases.  相似文献   

Ultraviolet radiation on the surface of Mars and the Beagle 2 UV sensor     

M.R. Patel  J.C. ZarneckiD.C. Catling 《Planetary and Space Science》2002,50(9):915-927

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Can radiative forcing be limited to 2.6 Wm−2 without negative emissions from bioenergy AND CO2 capture and storage?     

James Edmonds  Patrick Luckow  Katherine Calvin  Marshall Wise  Jim Dooley  Page Kyle  Son H. Kim  Pralit Patel  Leon Clarke 《Climatic change》2013,118(1):29-43

Combining bioenergy and carbon dioxide (CO₂) capture and storage (CCS) technologies (BECCS) has the potential to remove CO₂ from the atmosphere while producing useful energy. BECCS has played a central role in scenarios that reduce climate forcing to low levels such as 2.6 Wm^?2. In this paper we consider whether BECCS is essential to limiting radiative forcing (RF) to 2.6 Wm^?2 by 2100 using the Global Change Assessment Model, a closely coupled model of biogeophysical and human Earth systems. We show that BECCS can potentially reduce the cost of limiting RF to 2.6 Wm^?2 by 2100 but that a variety of technology combinations that do not include BECCS can also achieve this goal, under appropriate emissions mitigation policies. We note that with appropriate supporting land-use policies terrestrial sequestration could deliver carbon storage ranging from 200 to 700 PgCO₂-equiavalent over the 21st century. We explore substantial delays in participation by some geopolitical regions. We find that the value of BECCS is substantially higher under delay and that delay results in higher transient RF and climate change. However, when major regions postponed mitigation indefinitely, it was impossible to return RF to 2.6 Wm^?2 by 2100. Neither finite land resources nor finite potential geologic storage capacity represented a meaningful technical limit on the ability of BECCS to contribute to emissions mitigation in the numerical experiments reported in this paper.  相似文献   

Trade-offs of different land and bioenergy policies on the path to achieving climate targets     

Katherine Calvin  Marshall Wise  Page Kyle  Pralit Patel  Leon Clarke  Jae Edmonds 《Climatic change》2014,123(3-4):691-704

Many papers have shown that bioenergy and land-use are potentially important elements in a strategy to limit anthropogenic climate change. But, significant expansion of bioenergy production can have a large terrestrial footprint. In this paper, we test the implications for land use, the global energy system, emissions and mitigation costs of meeting a specific climate target, using a single fossil fuel and industrial sector policy instrument, but with five alternative bioenergy and land-use policy architectures. These scenarios are illustrative in nature, and designed to explore trade-offs. We find that the policies we examined have differing effects on the different segments of the economy. Comprehensive land policies can reduce land-use change emissions, increasing allowable emissions in the energy system, but have implications for the cost of food. Bioenergy penalties and constraints, on the other hand, have little effect on food prices, but result in less bioenergy and thus can increase mitigation costs and energy prices.  相似文献   

A time-domain simulator for an oscillating water column in irregular waves at model scale     

R. Gervelas  F. Trarieux  M. Patel 《Ocean Engineering》2011,38(8-9):1007-1013

This paper presents a 1D time-domain model for an oscillating water column (OWC) based on previous works on trapped air cavities for marine vehicles. The paper describes the coupling between the hydrodynamic and the thermodynamic forces for an OWC with an orifice. The model enables to obtain the water elevation and pressure variation inside the chamber in the time-domain for regular and irregular waves. The numerical predictions are compared with experimental data performed on a model scale OWC.  相似文献