نتایج جستجو برای: vegetation cover maps

تعداد نتایج: 249983  

Journal: :Int. J. Applied Earth Observation and Geoinformation 2013
Nea Kuusinen Erkki Tomppo Frank Berninger

We use a linear unmixing approach to test how land use and forestry maps, in combination with the MODIS BRDF/albedo product, can be used to estimate land cover type albedos in boreal regions. Operational land use maps from three test areas in Finland and Canada were used to test the method. The resulting endmember albedo estimates had low standard errors of the mean and were realistic for the m...

2014
Roxanne S. Beltran Nissa Kreidler Dirk H. Van Vuren Scott A. Morrison Erika S. Zavaleta Kelly Newton Bernie R. Tershy Donald A. Croll

Understanding how insular ecosystems recover or are restructured after the eradication of an invasive species is crucial in evaluating conservation success and prioritizing island conservation efforts. Globally, herbivores have been removed from 762 islands, most with limited active restoration actions following eradication. Few studies have documented the effects of invasive herbivore removal ...

2013
Miguel L. Villarreal Laura M. Norman Robert H. Webb Raymond M. Turner

Vegetation and land-cover changes are not always directional but follow complex trajectories over space and time, driven by changing anthropogenic and abiotic conditions. We present a multi-observational approach to land-change analysis that addresses the complex geographic and temporal variability of vegetation changes related to climate and land use. Using land-ownership data as a proxy for l...

Journal: Desert 2012
F. Mellati H. Arzani H. Azarnivand H.R. Keshtkar S.K. Alavipanah

Land cover is one of basic data layers in geographic information system for physical planning and environmentalmonitoring. Digital image classification is generally performed to produce land cover maps from remote sensing data,particularly for large areas. In the present study the multispectral image from IRS LISS-III image along with ancillary datasuch as vegetation indices, principal componen...

1985
T. Simoniello

Resilience is a fundamental concept for understanding vegetation as a dynamic component of the climate system. It expresses the ability of ecosystems to tolerate disturbances and to recover their initial state. Recovery times are basic parameters of the vegetation’s response to forcing and, therefore, are essential for describing realistic 5 vegetation within dynamical models. Healthy vegetatio...

H. Ahmad Husni Mohd H. Ridzwan Abd M. Ajorlo,

Empirical models are important tools for relating field-measured biophysical variables to remotely sensed data. Regression analysis has been a popular empirical method of linking these two types of data to estimate variables such as biomass, percent vegetation canopy cover, and bare soil. This study was conducted in a semi-arid rangeland ecosystem of Qazvin province, Iran. This paper presents t...

One of the important parameters, that reduce negative influence of the other known parameters, is cover vegetation. In this study were estimated cover vegetation influence in soil erosion of Razin basin in Kermanshah province that is our study area. The first step is preparation map of NDVI obtained & category of cover vegetation by the Landsat TM data. Then Revised Universal Soil Loss Equation...

Journal: :مجله مرتعداری 0

in this study, we applied classification methods and geographic information system(gis) techniques to identify vegetation structures in andevar rangelands. homogenous work unit maps were produced by overlaying the layers of slope, aspect and digital elevation. totally 95 homogenous units were determined in which the field studies were carried out. vegetation sampling was done in 69 transects an...

2010
Qian Li Yongkang Xue

The Tibetan Plateau (TP) is a key region of land–atmosphere interactions with severe eco-environment degradation. This study uses an atmospheric general circulation model, NCEP GCM/SSiB, to present the major TP summer climate features for six selected ENSO years and preliminarily assess the possible impact of land cover change on the summer circulation over the TP. Compared to Reanalysis II dat...

2004
E. R. MICHELI J. W. KIRCHNER E. W. LARSEN

Riparian forest vegetation is widely believed to protect riverbanks from erosion, but few studies have quantified the effect of riparian vegetation removal on rates of river channel migration. Measured historical changes in a river channel centreline, combined with mapped changes in floodplain vegetation, provide an opportunity to test how riparian vegetation cover affects the erodibility of ri...

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