نتایج جستجو برای: canopy water storage

تعداد نتایج: 730917  

2006
Johannes Dietz Dirk Hölscher Christoph Leuschner

Management activities alter the structure of many tropical forest stands which can be expected to influence the magnitude of canopy water fluxes. The objectives of this study were to determine throughfall, stemflow and rainfall interception in differently managed forest stands, and to relate the observed pattern of rainfall partitioning to stand structural characteristics. The study was conduct...

2001
I. MANAKOS

Precision farming requires information about the present status of the vegetation canopy. Remote sensing products can provide such information. The general investigation approach is based on the evaluation of remotely sensed data by the inversion of physical backscatter models and coupled growth models. The presented paper describes the measurement strategy, developed for the establishment of a...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2003
Eric A Graham Stephen S Mulkey Kaoru Kitajima Nathan G Phillips S Joseph Wright

Recent global-scale analyses indicate that climate variability affects net carbon storage but regard temperature and precipitation to be the main contributors. Seasonal and interannual variation in light availability may also limit CO(2) uptake. As an experimental test of light limitation by cloud cover during tropical rainy seasons and by the unusually heavy cloud cover associated with La Niña...

Journal: :Tree physiology 2004
Frederick C Meinzer Shelley A James Guillermo Goldstein

In large trees, the daily onset of transpiration causes water to be withdrawn from internal storage compartments, resulting in lags between changes in transpiration and sap flow at the base of the tree. We measured time courses of sap flow, hydraulic resistance, plant water potential and stomatal resistance in co-occurring tropical forest canopy trees with trunk diameters ranging from 0.34-0.98...

2005
V. Rivalland

A modelling study is performed in order to quantify the relative effect of allowing for the physiological properties of an undergrowth grass sward on total canopy water and carbon fluxes of the Le-Bray forest (Les-Landes, Southwestern France). The Le-Bray forest consists of maritime pine and an herbaceous undergrowth (purple moor-grass), which is characterised by a low stomatal control of trans...

2006
Georgianne W. Moore M. Keith Owens

During the last century, the density of Ashe juniper (Juniperus ashei Buchholz) has greatly increased in oak savannahs of central Texas. Recently, juniper removal has been advocated as a regional water conservation tool. In this study, we investigated whether juvenile trees released from an overstory canopy after clearing exhibited accelerated growth and water consumption. We compared leaf-leve...

2003
P. J. Zarco-Tejada C. A. Rueda S. L. Ustin

Statistical and radiative-transfer physically based studies have previously demonstrated the relationship between leaf water content and leaf-level reflectance in the near-infrared spectral region. The successful scaling up of such methods to the canopy level requires modeling the effect of canopy structure and viewing geometry on reflectance bands and optical indices used for estimation of wat...

2002
Pablo J. Zarco-Tejada Susan L. Ustin

Radiative-transfer physically-based studies have previously demonstrated the relationship between leaf water content and leaf-level reflectance in the near-infrared spectral region. The successful scaling up of such methods to the canopy level requires modeling the effect of canopy structure and viewing geometry on reflectance bands and optical indices used for estimation of water content, such...

2013
Guy Serbin Philip Rasmussen

Ground penetrating radar (GPR) with a suspended 1 GHz horn antenna was deployed for measurement of soil water contents and dwatj wheat canopy reflections over bare and electrically terminating sutjaces. Sutjace reflection (SR) magnitudes and propagation times (PI) were used to independently calculate bulk soil dielectric constant and soil water contents. Measurements over wheat canopy shows tha...

Journal: :آب و خاک 0
وحیدرضا وردی نژاد سینا بشارت هیراد عبقری حجت احمدی

abstract to optimal use of available water, irrigation scheduling is important to over scarcity of water resources in arid and semi-arid area. in this research to estimate of maximum allowable deficit (or: management allowed depletion) and irrigation scheduling of fodder mays based on canopy-air temperature difference, a field study was conducted in agricultural faculty of karaj. the lower limi...

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