Estimation of water cloud model vegetation parameters using a genetic algorithm     

Kamal Kumar  K.S. Hari Prasad  M.K. Arora 《水文科学杂志》2013,58(4):776-789

Abstract

The water cloud model is used to account for the effect of vegetation water content on radar backscatter data. The model generally comprises two parameters that characterize the vegetated terrain, A and B, and two bare soil parameters, C and D. In the present study, parameters A and B were estimated using a genetic algorithm (GA) optimization technique and compared with estimates obtained by the sequential unconstrained minimization technique (SUMT) from measured backscatter data. The parameter estimation was formulated as a least squares optimization problem by minimizing the deviations between the backscatter coefficients retrieved from the ENVISAT ASAR image and those predicted by the water cloud model. The bias induced by three different objective functions was statistically analysed by generating synthetic backscatter data. It was observed that, when the backscatter coefficient data contain no errors, the objective functions do not induce any bias in the parameter estimation and the true parameters are uniquely identified. However, in the presence of noise, these objective functions induce bias in the parameter estimates. For the cases considered, the objective function based on the sum of squares of normalized deviations with respect to the computed backscatter coefficient resulted in the best possible estimates. A comparison of the GA technique with the SUMT was undertaken in estimating the water cloud model parameters. For the case considered, the GA technique performed better than the SUMT in parameter estimation, where the root mean squared error obtained from the GA was about half of that obtained by the SUMT.

Editor D. Koutsoyiannis; Associate editor L. See

Citation Kumar, K., Hari Prasad, K.S. and Arora, M.K., 2012. Estimation of water cloud model vegetation parameters using a genetic algorithm. Hydrological Sciences Journal, 57 (4), 776–789.  相似文献   

Strain and Crystallographic Fabric in Mesoscopic Ductile Shear Zones of Garhwal Himalaya     

Hari B. Srivastava  Atul Sahai  Surya N. Lal 《Gondwana Research》2000,3(3)

The MCT Zone of Bhagirathi valley of Garhwal Himalaya is characterized by numerous mesoscopic ductile shear zones. These shear zones are developed in response to nearly NNE-SSW maximum horizontal compression and provide an opportunity to study the variation in strain and crystallographic fabrics within the ductile shear zones.The grain shape and orientation of quartz under microscope reflect that strain is higher in the center and it progressively decreases towards the shear zone boundary. The preferred orientation of quartz c-axes across the shear zone suggests that the single girdle of the quartz c-axes are probably first developed at the shear zone boundary and become prominent in the center of shear zone with increase in the intensity of deformation. The strong crystallographic preferred orientation normal to foliation suggests that the internal deformation of the quartz might have taken place by dislocation creep mechanism exhibiting a non-coaxial deformation history.  相似文献   

Geometrical analysis of mesoscopic shear zones in the crystalline rocks of MCT zone of Garhwal Higher Himalaya   总被引：1，自引：0，他引：1  

Hari B. Srivastava  Nihar R. Tripathy 《Journal of Asian Earth Sciences》2007,30(5-6):599-612

The crystalline rocks of the MCT Zone of Garhwal Higher Himalaya exhibit well-preserved mesoscopic shear zones. Majority of these shear zones are of ductile and brittle ductile type with both sinistral and dextral sense of movement. Detailed analysis of mesoscopic shear zones reveals that sinistral shear zones exhibit a strike variation from NNE to ENE and dextral shear zones exhibit variation from NNW to WNW directions thus forming a conjugate pair. The bisectors of statistically preferred orientations of the two sets of the shears indicate that they generated due to NNE–SSW horizontal compression. These dextral and sinistral shear zones exhibit strike–slip geometry developed during progressive ductile shearing.  相似文献   

Irrigation Water Requirements and Supply Analysis in Dehradun Region—An Integrated Remote Sensing and GIS Approach     

K. H. V. Durga Rao  C. S. Krishna Kumar  V. Hari Prasad 《Journal of the Indian Society of Remote Sensing》2001,29(1-2):59-67

The paper focuses on analysing the irrigation water supply and demand of different crops under three main canals for kharif and rabi seasons in Dehradun region of Uttaranchal state. Crop acreage maps of rabi and kharif seasons have been prepared using LANDSAT TM 5 digital data by applying different image processing and classification techniques. Crop water and irrigation water requirements of different crops have been computed using CROPWAT computer program. Canal discharges have been compared with the irrigation water planning and management and found to be more than the irrigation water requirements in many months, that shows the need of revising the irrigation water management.  相似文献   

对《中国土壤系统分类（修订版）》（英文版）的评论     

Dr.HariEswarn 《山地学报》2002,20(2):256-256

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Rain induced shallow landslide hazard assessment for ungauged catchments   总被引：1，自引：0，他引：1  

Raj Hari Sharma  Narendra Man Shakya 《Hydrogeology Journal》2008,16(5):871-877

A physically based distributed slope stability model derived from the integration of hydrologic analysis and slope stability analysis is presented for GIS based modeling on a catchment scale. The catchment is represented by a mesh of squares with vertical columns. The hydrologic model calculates subsurface flow and resulting pore-water pressure during rainfall in each cell for every time step. The slope stability module then calculates the stability of each cell for the changing water pressure scenario. There are very few input data requirements, which makes the model applicable to ungauged catchments, also where the record of the past landslides and associated rainfall are not available. The model was tested in Garjuwa catchment, Nepal where all landslide scars were documented. The model reproduces the observed distribution of landslide locations in a consistent way. Several model runs were conducted, increasing the intensity of rainfall to see corresponding increase in instability. The results show that there is a critical rainfall intensity for the catchment, beyond which increase in rainfall intensity does not increase instability significantly.  相似文献   

Pioneer Venus Orbiter Measurements of Solar EUV Flux During Solar Cycles 21 and 22     

K. K. Mahajan  Hari Om Upadhyay  N. K. Sethi  W. R. Hoegy  W. D. Pesnell  L. H. Brace 《Solar physics》1998,177(1-2):203-216

The Pioneer Venus Orbiter (PVO) had on board the electron temperature probe experiment which measured temperature and concentration of electrons in the ionosphere of Venus. When the probe was outside the Venus ionosphere and was in the solar wind, the probe current was entirely due to solar photons striking the probe surface. This probe thus measured integrated solar EUV flux (Ipe) over a 13-year period from January 1979 to December 1991, thereby covering the declining phase of solar cycle 21 and the rising phase of solar cycle 22. In this paper, we examine the behavior of Ipe translated to the solar longitude of Earth (to be called EIpe) during the two solar cycles. We find that total EUV flux changed by about 60% during solar cycle 21 and by about 100% in solar cycle 22. We also compare this flux with other solar activity indicators such as F_10.7 , Lα, and the solar magnetic field. We find that while the daily values of EIpe are highly correlated with F_10.7 (correlation coefficient 0.87), there is a large scatter in EIpe for any value of this Earth-based index. A comparison of EIpe with SME and UARS SOLSTICE Lα measurements taken during the same period shows that EIpe tracks Lα quite faithfully with a correlation coefficient of 0.94. Similar comparison with the solar magnetic field (Bs) shows that EIpe correlates better with Bs than with F_10.7 . We also compare EIpe with total solar irradiance measured during the same period.  相似文献   

Seasonal discharge and chemical flux variations of rivers flowing into the Bayhead canal of Durban Harbour,South Africa     

Kavandren Moodley  Srinivasan Pillay  Keshia Pather  Hari Ballabh 《中国地球化学学报》2016,35(4):340-353

The u Mhlatuzana, u Mbilo and a Manzimnyama river catchments located on the eastern seaboard of the Kwa Zulu-Natal province, South Africa, form the core of urbanization and industrialization, contributing the only natural freshwater inflows to the Bayhead Canal portion of the Durban Harbour. In this study, seasonal discharges and physico–chemical water properties were used to quantitatively determine the material mass transport capacity of the river systems on the basis of hydrographic inputs and chemical loading from the surrounding land use sectors.The mass transport of the total dissolved solids（TDS）,ammonia（NH₄）, phosphorous（P）, aluminum（Al）, calcium（Ca）, copper（Cu）, chromium（Cr）, mercury（Hg）, potassium（K）, magnesium（Mg）, sodium（Na）, nickel（Ni）, lead（Pb）, sulphur（S） and vanadium（V） was determined for each river. Results indicated that land use, seasonality and river flow were significant determinants for the material loading in the rivers and the receiving port waters. The spatio-temporal distribution patterns of chemical fluxes indicated that industrial activity associated with the a Manzimnyama canal contributed the most, with regards to TDS, NH₄, Ca, K, Mg, Na, S and V, loading in both wet and dry seasons, as well as Al, Cu, Hg and Pb during the dry season. Similarly, industrial activity associated with the u Mbilo/u Mhlatuzana Canal at the lower reaches accounted for the highest P, Al, Cu and Pb fluxes in the wet season alone. Fluxes of these parameters are used to explain theobserved elemental concentrations and patterns of the receiving port waters of the Bayhead Canal.  相似文献   

Frequency dependence of equatorial ionospheric scintillations     

M R Deshpande  R G Rastogi  Hari Om Vats  K Davies 《Journal of Earth System Science》1978,87(7):173-178

Simultaneous observations of amplitude scintillations at 40 MHz, 140 MHz and 360 MHz radiated from ATS-6 satellite at 34° E longitude were made at Ootacamund near the magnetic equator in India. It has been found that the frequency variation of scintillation index (S ₄) isS ₄ ∞f ^?n , withn being about 1·2 only for weak scintillations, i.e., so long as the scintillation index does not exceed 0·6 at the lower frequency. For strong scintillations (S ₄>0·6) where multiple scattering may be present, the exponentn itself is a function of the intensity of scintillation, the scintillation indices at two frequencies are related by:S ₄(f ₁)=S ₄(f ₂) exp [1·3 log(f ₂/f ₁)(1?S ₄(f ₂)] so long asf ₂/f ₁≤3. Thus knowing scintillation index at a given frequency one can estimate the scintillation index at another frequency. This will be of significant importance for communication problems. Evidence is also shown for the reversal of the frequency law in cases of intense scintillations.  相似文献   

Environmental geoinformaicts of fast growing Himalaya’s foothill towns and surrounding: concept and implementation     

Pradeep K. Rawat  Charu C. Pant  Hari Krishna Nibanupud 《Earth Science Informatics》2016,9(1):1-19

Himalaya foothill zone have fragile geo-environment due to active tectonics and dynamic hydrological process and its associated reshaped geomorphology. Rapid urbanization and development of new colonies leads to high rate of land use change and natural resource degradation since last three decades which has been accumulating the fragility of the area. Consequently entire Himalaya foothill zone requires a comprehensive local level geo-environmental appraisal for effective sustainable development planning of the region. Keep in view this; the Ramnagar Himalayan Foothill area (RHFA) in district Nainital, Uttarakhand (India) has been selected for the case illustration. The main objective of the study was to develop a GIS database on Ramnagar environmental geo-informatics (REGI) to facilitate all the concern line departments to implement their socioeconomic developmental activities in the most suitable and safe places throughout the study area. REGI suggests, although landscape of the study area have few favorable conditions for the inhabitant (i.e. maximum proportion (92 %) of the study area enjoys sub-tropical to sub-temperate climatic conditions, easy approachable, thick vegetation cover, rich water resources) but the active tectonics and dynamic hydrological process and its associated reshaped geomorphology poses a stressed geo-environment which need to be consider to formulate a decision support system (DSS) for sustainable development planning.  相似文献