نتایج جستجو برای: Vegetation canopy

تعداد نتایج: 59140  

2004
Guo-Yue Niu Zong-Liang Yang Katherine G. Jackson

[1] This paper addresses the effects of canopy physical processes on snow mass and energy balances in boreal ecosystems. We incorporate new parameterizations of radiation transfer through the vegetation canopy, interception of snow by the vegetation canopy, and under-canopy sensible heat transfer processes into the Versatile Integrator of Surface and Atmosphere (VISA) and test the model results...

ژورنال: مرتع 2021
Bagheri, Setareh, Jafari, Mohammad, Malekian, Arash, Peyrvand, Vahid, Tamartash, Reza, Tatian, Mohammadreza,

Using satellite imagery is a reasonable option to overcome the field visits problems and limitations to evaluate the vegetation cover over the years. The present research has conducted to specify the percentage of vegetation cover of rangelands using Geographic Information System (GIS) and vegetation indices. The study area is located in Qazvin plain rangelands, Iran. In this study, the MODIS s...

Risks assessment of forest project implementation in spatial density changes of forest under canopy vegetation using artificial neural network modeling approach   Nowadays, environmental risk assessment has been defined as one of the effective in environmental planning and policy making. Considering the position and structure of vegetation on the forest floor, the main role of forest under ca...

1973
Khil-ha Lee R. Chawn Harlow Eleanor J. Burke James Shuttleworth

This paper reports the application to vegetation canopies of a coherent model for the propagation of electromagnetic radiation through a stratified medium. The resulting multi-layer vegetation model is plausibly realistic in that it recognises the dielectric permittivity of the vegetation matter, the mixing of the dielectric permittivities for vegetation and air within the canopy and, in simpli...

Journal: :Remote Sensing 2014
Davide Cammarano Glenn J. Fitzgerald Raffaele Casa Bruno Basso

Remotely sensed vegetation indices have been extensively used to quantify plant and soil characteristics. The objectives of this study were to: (i) compare vegetation indices developed at different scales for measuring canopy N content (g∙N∙m −2 ) and concentration (%); and (ii) evaluate the effects of soil background reflectance, cultivar, illumination and atmospheric conditions on the ability...

2008
David R. Bedford Eric E. Small

Spatial patterns of soil properties are linked to patchy vegetation in arid and semi-arid landscapes. The patterns of soil properties are generally assumed to be linked to the ecohydrological functioning of patchy dryland vegetation ecosystems. We studied the effects of vegetation canopy, its spatial pattern, and landforms on soil properties affecting overland flow and infiltration in shrubland...

Journal: :مرتع و آبخیزداری 0
ملوک رویان فارغ التحصیل کارشناسی ارشد رشته مرتعداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران عادل سپهری دانشیار دانشکده مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران عبدالرسول سلمان ماهینی دانشیار دانشکده شیلات و محیط زیست، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

remote sensing and aerial photographs are used to produce medium to small scale images. however, for detailed information especially to estimate rangeland vegetation canopy cover there is a need to larger scale images. it is therefore necessary to study the technical applicability of different devices such as short range light airplanes, kites, gliders and balloons. in this research, we focused...

Journal: :journal of rangeland science 2014
seyyed morteza abtahi amr ali shahmoradi ehsan zandi esfahan

abstract. the purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in haftooman, khoor and biabanak deserts, iran. for this purpose, after determining vegetation types and the associated species, the type of rangeland utilization, grazing season, the livestock type, the other relevant information, vegetation da...

Amr Ali Shahmoradi Ehsan Zandi Esfahan Seyyed Morteza Abtahi,

Abstract. The purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in Haftooman, Khoor and Biabanak deserts, Iran. For this purpose, after determining vegetation types and the associated species, the type of rangeland utilization, grazing season, the livestock type, the other relevant information, vegetation da...

2005
Dinesh Bohra

The emission from the vegetation canopy depends on the type of vegetation and the frequencies at which the emission is measured. For studying the vegetation canopy of a tree, the dielectric constant of its constituent is measured at microwave frequencies. In this study the dielectric constant is measured using waveguide cell method and its scattering coefficient is estimated using perturbation ...

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