نتایج جستجو برای: vegetation index

تعداد نتایج: 435690  

The subject of outdoor thermal comfort has been researched since 1970. Due to its differences with indoor thermal comfort, it must be assessed with the proper indices. Also, the outdoor thermal comfort of each geographical region must be assessed independently. This research aims to study the measurement indices of outdoor thermal comfort and subsequently determine the most relevant index to as...

2017
Wenqian Zhao Xiang Zhao Tao Zhou Donghai Wu Bijian Tang Hong Wei

Along with global climate change, the occurrence of extreme droughts in recent years has had a serious impact on the Amazon region. Current studies on the driving factors of the 2005 and 2010 Amazon droughts has focused on the influence of precipitation, whereas the impacts of temperature and radiation have received less attention. This study aims to explore the climate-driven factors of Amazon...

2014
Yu Zhou Li Zhang Jingfeng Xiao Shiping Chen Tomomichi Kato Guangsheng Zhou

Gross primary productivity (GPP) is a key component of ecosystem carbon fluxes and the carbon balance between the biosphere and the atmosphere. Accurate estimation of GPP is essential for quantifying plant production and carbon balance for grasslands. Satellite-derived vegetation indices (VIs) are often used to approximate GPP. The widely used VIs include atmospherically resistant vegetation in...

Journal: :journal of rangeland science 0
mahtab safari shad phd student, department of natural resource, university of sari, iran. alireza ildoromi associate professor, dept of range& watershed management, malayer university iran. davoud akhzari davoud akhzari, department of watershed and rangeland management, malayer university, malayer 6571995863, iran. e-mail: [email protected], [email protected]

drought is a major problematic phenomenon mostly for semi-arid areas of iran. during drought periods, reduction in vegetation levels causes such problems as soil erosion, surface runoff, flood risk, etc. therefore, the assessment of drought effects on plant covers is the most important issue. this research was conducted in 2015 using the extracted vegetation indices from moderate resolution ima...

2013
Fazel Amiri Abdul Rashid B. Mohamed Shariff

To determine suitable indices for vegetation cover and production assessment based on remote sensing data, simultaneous digital data with field data belonged to summer rangeland of southern part of Isfahan province were analyzed. During 2 years of monitoring, annuals, grasses, forbs and shrubs vegetation cover and total production data from sixty 1 square meter plots in each site were collected...

2017
Erika Andujar Nir Y. Krakauer Chuixiang Yi Felix Kogan

Remote sensing is used for monitoring the impacts of meteorological drought on ecosystems, but few large-scale comparisons of the response timescale to drought of different vegetation remote sensing products are available. We correlated vegetation health products derived from polar-orbiting radiometer observations with a meteorological drought indicator available at different aggregation timesc...

2015
Sharon Leigh Cundill Harald van der Werff Mark van der Meijde

The use of data from multiple sensors is often required to ensure data coverage and continuity, but differences in the spectral characteristics of sensors result in spectral index values being different. This study investigates spectral response function effects on 48 spectral indices for cultivated grasslands using simulated data of 10 very high spatial resolution sensors, convolved from field...

2017
Feng Zhang Guangsheng Zhou

We estimated the light use efficiency (LUE) via vegetation canopy chlorophyll content (CCCcanopy) based on in situ measurements of spectral reflectance, biophysical characteristics, ecosystem CO 2 fluxes and micrometeorological factors over a maize canopy in Northeast China. The results showed that among the common chlorophyll-related vegetation indices (VIs), CCCcanopy had the most obviously e...

Journal: :The Professional geographer : the journal of the Association of American Geographers 2013
Douglas A Stow John R Weeks Sory Toure Lloyd L Coulter Christopher D Lippitt Eric Ashcroft

The objectives are to (1) quantify, map, and analyze vegetation cover distributions and changes across Accra, Ghana, for 2002 and 2010; and (2) examine the statistical relationship between vegetation cover and a housing quality index (HQI) for 2000 at the neighborhood level. Pixel-level vegetation cover maps derived using threshold classification of 2002 and 2010 QuickBird normalized difference...

2004
Andrés Viña Geoffrey Henebry Anatoly A. Gitelson Geoffrey M. Henebry

[1] Synoptic monitoring of vegetation dynamics relies on satellite observations of the distinctive spectral contrast between red and near infrared reflectance that photosynthetically active green vegetation exhibits. It has long been recognized that the Normalized Difference Vegetation Index (NDVI) suffers a rapid decrease of sensitivity at moderate-to-high densities of photosynthetic green bio...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید