نتایج جستجو برای: different vegetation

تعداد نتایج: 1800636  

2017
Cong Wang Jing Li Qinhuo Liu Bo Zhong Shanlong Wu Chuanfu Xia

Remote-sensing phenology detection can compensate for deficiencies in field observations and has the advantage of capturing the continuous expression of phenology on a large scale. However, there is some variability in the results of remote-sensing phenology detection derived from different vegetation parameters in satellite time-series data. Since the enhanced vegetation index (EVI) and the le...

Journal: :Global change biology 2015
Jianguang Tan Shilong Piao Anping Chen Zhenzhong Zeng Philippe Ciais Ivan A Janssens Jiafu Mao Ranga B Myneni Shushi Peng Josep Peñuelas Xiaoying Shi Sara Vicca

Over the last century the Northern Hemisphere has experienced rapid climate warming, but this warming has not been evenly distributed seasonally, as well as diurnally. The implications of such seasonal and diurnal heterogeneous warming on regional and global vegetation photosynthetic activity, however, are still poorly understood. Here, we investigated for different seasons how photosynthetic a...

1999
Alfredo Huete Chris Justice Wim van Leeuwen

One of the primary interests of the Earth Observing System (EOS) program is to study the role of terrestrial vegetation in large-scale global processes with the goal of understanding how the Earth functions as a system. This requires an understanding of the global distribution of vegetation types as well as their biophysical and structural properties and spatial/temporal variations. Vegetation ...

2017
Kelly Elschot Anke Vermeulen Wouter Vandenbruwaene Jan P. Bakker Tjeerd J. Bouma Julia Stahl Henk Castelijns Stijn Temmerman

The relative impact of top-down control by herbivores and bottom-up control by environmental conditions on vegetation is a subject of debate in ecology. In this study, we hypothesize that top-down control by goose foraging and bottom-up control by sediment accretion on vegetation composition within an ecosystem can co-occur but operate at different spatial and temporal scales. We used a highly ...

2015
Daniel J. Howes Paul H. Hutton

Restoration activities in the Central Valley of California and elsewhere require accurate evapotranspiration information, which can then be used for a wide variety of surface and subsurface hydrologic evaluations. However, directly measuring evapotranspiration can be difficult or impossible depending on the evaluation’s time frame. Transferability of measured evapotranspiration in time and spac...

2010
M. Förster A. Frick C. Schuster B. Kleinschmit

Multi-temporal and multi-sensor satellite information can supply valuable information about vegetation species, especially in the context of biodiversity. Main focus of the presented project CARE-X is the development of a remote sensing technology for the European monitoring of NATURA 2000 areas. For this type of monitoring, information about the structure and composition of the existing vegeta...

Journal: :Remote Sensing 2015
Yu Zhou Li Zhang Rasmus Fensholt Kun Wang Irina Vitkovskaya Feng Tian

Central Asia comprises a large fraction of the world’s drylands, known to be vulnerable to climate change. We analyzed the inter-annual trends and the impact of climate variability in the vegetation greenness for Central Asia from 1982 to 2011 using GIMMS3g normalized difference vegetation index (NDVI) data. In our study, most areas showed an increasing trend during 1982–1991, but experienced a...

Journal: :journal of rangeland science 2010
m. zaremehrjardiri

the objective of this study was to assess the relationship betweenvegetation, landform and physicochemical properties of soil. at the first terrainmap unit were provided using the landsat thematic mapper (tm) satellite images,aerial photograph, topographical and geology map. field sampling was done in therepresentative area using plot sampling. 104 plots 100 m2 were sampled in eachplot landform...

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...

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