نتایج جستجو برای: vegetation dynamics

تعداد نتایج: 482770  

Journal: :Remote Sensing 2010
Grant M. Casady Stuart E. Marsh

Ecosystem response to disturbance is influenced by environmental conditions at a number of scales. Changes in climate have altered fire regimes across the western United States, and have also likely altered spatio-temporal patterns of post-fire vegetation regeneration. Fire occurrence data and a vegetation index (NDVI) derived from the NOAA Advanced Very High Resolution Radiometer (AVHRR) were ...

2018
Michael M Loranty Logan T Berner Eric D Taber Heather Kropp Susan M Natali Heather D Alexander Sergey P Davydov Nikita S Zimov

Arctic ecosystems are characterized by a broad range of plant functional types that are highly heterogeneous at small (~1-2 m) spatial scales. Climatic changes can impact vegetation distribution directly, and also indirectly via impacts on disturbance regimes. Consequent changes in vegetation structure and function have implications for surface energy dynamics that may alter permafrost thermal ...

2006
Martin Claussen Jens Fohlmeister Andrey Ganopolski Victor Brovkin

[1] The astronomical theory of climate variations predicts that the climatic precession which changes the seasonal distance between Earth and Sun does not affect the annual mean irradiation at any given latitude. However, previous modeling studies suggest that during interglacials, the interaction between atmosphere, vegetation and ocean can transform the seasonal forcing by precession into an ...

Journal: :global journal of environmental science and management 0
p. gandiwa school of agricultural, earth and environmental sciences, university of kwazulu-natal, private bag x01, scottsville, pietermaritzburg, south africa j. finch school of agricultural, earth and environmental sciences, university of kwazulu-natal, private bag x01, scottsville, pietermaritzburg, south africa t. hill school of agricultural, earth and environmental sciences, university of kwazulu-natal, private bag x01, scottsville, pietermaritzburg, south africa

mapungubwe cultural landscape (mcl) woody vegetation was characterized to establish structural and compositional attributes. stratified random sampling based on major soil types was used and nine plant variables were measured in 137(20x30) m2 sampling plots; these being genera, species and family names; basal circumference; plant height; depth and diameter of tree canopy; number of stems per pl...

2015
Yohei Sawada Toshio Koike Jeffrey P. Walker

Despite the importance of the coupling between vegetation dynamics and root-zone soil moisture in land-atmosphere interactions, there is no land data assimilation system (LDAS) that currently addresses this issue, limiting the capacity to positively impact weather and seasonal forecasting. We develop a new LDAS that can improve the skill of an ecohydrological model to simulate simultaneously su...

2001
Jeffrey S. Wilson Timothy S. Brothers Eugenio J. Marcano Pedro Henriquez Urena John F. Kennedy

Spatial and temporal vegetation contrasts between the nations of Haiti and the Dominican are analyzed using NDVI data derived from 30m resolution Landsat imagery and 8km resolution AVHRR imagery from the NOAA / NASA Pathfinder database. Analysis of vegetation dynamics in the Hispaniola border region indicates denser vegetation cover and a stronger correlation between elevation, slope, and NDVI ...

2010
G. C. Hurtt J. Fisk R. Q. Thomas R. Dubayah P. R. Moorcroft H. H. Shugart

[1] For more than a century, scientists have recognized the importance of vegetation structure in understanding forest dynamics. Now future satellite missions such as Deformation, Ecosystem Structure, and Dynamics of Ice (DESDynI) hold the potential to provide unprecedented global data on vegetation structure needed to reduce uncertainties in terrestrial carbon dynamics. Here, we briefly review...

Vegetation cover is an important component of terrestrial ecosystems that changes seasonally. Accurate parameterization of vegetation cover dynamics through developing indicators of periodic patterns can assist our understanding of vegetation-climate interactions. The current study was conducted to investigate and model vegetation changes in some phytogeographical regions of Iran including, Kha...

2005
Christopher A. Williams John D. Albertson

[1] While it is generally believed that the magnitude and composition of vegetation cover influence land-atmosphere water and carbon fluxes, observations indicate that in some cases, fluxes are insensitive to land cover contrasts. This seeming inconsistency may be resolved by contrasting fluxes over short and long timescales. To explore this potential contrast, we developed and tested a model d...

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