نتایج جستجو برای: different vegetation

تعداد نتایج: 1800636  

2003
Dominique Bachelet Ronald P. Neilson Thomas Hickler Raymond J. Drapek James M. Lenihan Martin T. Sykes Benjamin Smith Stephen Sitch Kirsten Thonicke

[1] Simulations of potential vegetation distribution, natural fire frequency, carbon pools, and fluxes are presented for two DGVMs (Dynamic Global Vegetation Models) from the second phase of the Vegetation/Ecosystem Modeling and Analysis Project. Results link vegetation dynamics to biogeochemical cycling for the conterminous United States. Two climate change scenarios were used: a moderately wa...

2011
Gabriela Woźniak Damian Chmura Agnieszka Błońska Barbara Tokarska-Guzik Edyta Sierka

The immense variety in plant diversity at the species level might explain why it is so difficult to establish strict generalizations in vegetation dynamics. In the last two decades many published research reports have shown that the introduction of the concept of plant functional groups (PEG) into the analysis of vegetation dynamics might be more informative in explaining spatiotemporal changes...

Journal: :Remote Sensing 2017
Shiliang Liu Yueqiu Zhang Fangyan Cheng Xiaoyun Hou Shuang Zhao

Grassland, as the primary vegetation on the Qinghai-Tibet Plateau, has been increasingly influenced by water availability due to climate change in last decades. Therefore, identifying the evolution of drought becomes crucial to the efficient management of grassland. However, it is not yet well understood as to the quantitative relationship between vegetation variations and drought at different ...

Journal: :Remote Sensing 2010
Jerry L. Hatfield John H. Prueger

The paper investigates the value of using distinct vegetation indices to quantify and characterize agricultural crop characteristics at different growth stages. Research was conducted on four crops (corn, soybean, wheat, and canola) over eight years grown under different tillage practices and nitrogen management practices that varied rate and timing. Six different vegetation indices were found ...

2009
P. Ferrazzoli D. Solimini

A computational model for estimating microwave scattering and emission from the earth’s surface covered with vegetation (MESCAM) has been developed. The model is founded on relevant electromagnetic properties of the vegetation and of the underlying terrain and takes into account multiple scattering both within the vegetation and between vegetation and underlying soil. By selecting the appropria...

2015
T. Wakita J. Susaki

In this study, we propose a method to accurately extract vegetation from terrestrial three-dimensional (3D) point clouds for estimating landscape index in urban areas. Extraction of vegetation in urban areas is challenging because the light returned by vegetation does not show as clear patterns as man-made objects and because urban areas may have various objects to discriminate vegetation from....

2010
Zhongjun Zhang Lixin Zhang Shaojie Zhao Xin Guoqing Sun

Passive microwave remote sensing techniques can be used to monitor freeze/thaw at frozen soil surface. Researches found that the negative spectral gradient at 19GHz and 37GHz was a good criteria for decision of frozen soil[1]. At vegetated area, to make the algorithm simple, vegetation scattering were ignored, only their attenuation were considered, which were kept constant, regardless of veget...

2002
Khil-ha Lee Eleanor J. Burke W. James Shuttleworth R. Chawn Harlow

Using the proposed Soil Moisture and Ocean Salinity (SMOS) mission as a case study, this paper investigates how the presence and nature of vegetation influence the values of geophysical variables retrieved from multi-angle microwave radiometer observations. Synthetic microwave brightness temperatures were generated using a model for the coherent propagation of electromagnetic radiation through ...

2000
Christopher D. Clegg Karl Ritz Bryan S. Griffiths

Total DNA was directly extracted from microbial populations in grassland soils taken from three geographically distinct upland sites at Garrigill, Aber and Sourhope, UK. Within each site, grasslands were categorised using the National Vegetation Classification into distinct vegetation sequences, namely unimproved, semi-improved and improved. Microbial community DNA was extracted from the differ...

Journal: :Global change biology 2015
John Harte Scott R Saleska Charlotte Levy

Ecosystem responses to climate change can exert positive or negative feedbacks on climate, mediated in part by slow-moving factors such as shifts in vegetation community composition. Long-term experimental manipulations can be used to examine such ecosystem responses, but they also present another opportunity: inferring the extent to which contemporary climate change is responsible for slow cha...

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