نتایج جستجو برای: vegetation canopy

تعداد نتایج: 59140  

Journal: :Remote Sensing 2016
Johannes Schreyer Tobia Lakes

Vegetation provides important functions and services in urban areas, and vegetation heights divided into vertical and horizontal units can be used as indicators for its assessment. Conversely, detailed area-wide and updated height information is frequently missing for most urban areas. This study sought to assess three vegetation height classes from a globally available TanDEM-X digital elevati...

Journal: :Remote Sensing 2013
Amanda S. Whitehurst Anu Swatantran J. Bryan Blair Michelle A. Hofton Ralph Dubayah

Canopy structure, the vertical distribution of canopy material, is an important element of forest ecosystem dynamics and habitat preference. Although vertical stratification, or “canopy layering,” is a basic characterization of canopy structure for research and forest management, it is difficult to quantify at landscape scales. In this paper we describe canopy structure and develop methodologie...

Journal: :journal of rangeland science 2015
mohamad taghi kashki amr ali shahmoradi ehsan zandi esfahan

abstract. rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. accordingly, data collection and measurements for evalu...

Journal: :Remote Sensing 2013
Ninni Saarinen Mikko Vastaranta Matti Vaaja Eliisa Lotsari Anttoni Jaakkola Antero Kukko Harri Kaartinen Markus Holopainen Hannu Hyyppä Petteri Alho

Vegetation plays an important role in stabilizing the soil and decreasing fluvial erosion. In certain cases, vegetation increases the accumulation of fine sediments. Efficient and accurate methods are required for mapping and monitoring changes in the fluvial environment. Here, we develop an area-based approach for mapping and monitoring the vegetation structure along a river channel. First, a ...

Journal: :Remote Sensing 2016
Geert J. Verhoeven Frank Vermeulen

Using Montarice in central Adriatic Italy as a case study, this paper focuses on the extraction of the spectral (i.e., plant colour) and geometrical (i.e., plant height) components of a crop canopy from archived aerial photographs, treating both parameters as proxies for archaeological prospection. After the creation of orthophotographs and a canopy height model using image-based modelling, new...

2004
Zhuo Wang Xubin Zeng Michael Barlage

Land surface albedo describes the fraction of incoming solar energy reflected at a given point and time, and hence determines the surface temperature and evapotranspiration. It is strongly dependent on the solar zenith angle and the three-dimensional structure of vegetation canopy (e.g., Yang et al. 2001; Schaaf et al. 2002). The land surface albedo in regional and global models can be specifie...

2008
Attila Nagy

Canopy analysis was carried out in order to classify the differences between vegetation types at the Szárazvölgy flotation sludge reservoir. Supervised classification methods were used to distinguish 8 vegetation types based on the spectral properties of the area: forest (Quercus sp.), young deciduous forest, reed (Phragmites sp.) and aquatic plants, false indigo (Amorpha fruticosa), Australian...

2015
Riccardo Tortini Thomas Hilker Nicholas C. Coops Zoran Nesic

Understanding plant photosynthesis, or Gross Primary Production (GPP), is a crucial aspect of quantifying the terrestrial carbon cycle. Remote sensing approaches, in particular multi-angular spectroscopy, have proven successful for studying relationships between canopy-reflectance and plant-physiology processes, thus providing a mechanism to scale up. However, many different instrumentation des...

2007
Kyu-Sung Lee Min-Jung Kook Jung-Il Shin Sun-Hwa Kim

Although there have been several studies on the spectral characteristics related to leaf water content, it remains unclear whether the spectral property of leaves can be extended to the canopy-level. In this study, we attempt to compare the spectral characteristics of forest vegetation in moderate drought condition observed by laboratory measurement and satellite hyperspectral image data. Spect...

2006
Urs Neumeier Carl L. Amos

Flow hindrance by salt-marsh vegetation is manifested in the structure of the tidal current; it has a significant impact on sediment transport and causes increased sediment accretion. The flow characteristics in 3 different vegetation types (Spartina maritima, Sp. anglica and Salicornia/Suaeda maritima) were measured on 3 salt-marshes in Portugal and England. Skimming flow develops above the Sp...

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