نتایج جستجو برای: leaf area index lai

تعداد نتایج: 1018301  

2006
Jiannan Hu Yin Su Bin Tan Dong Huang Wenze Yang Mitchell Schull Michael A. Bull John V. Martonchik David J. Diner Yuri Knyazikhin Ranga B. Myneni

The Multi-angle Imaging SpectroRadiometer (MISR) instrument provides global imagery at nine discrete viewing angles and four visible/nearinfrared spectral bands. MISR standard products include green leaf area index (LAI) of vegetation and fraction of photosynthetically active radiation absorbed by vegetation (FPAR). This paper describes the research basis for transitioning the MISR LAI/FPAR pro...

Journal: :Remote Sensing 2014
Mingliang Che Baozhang Chen Huifang Zhang Shifeng Fang Guang Xu Xiaofeng Lin Yuchen Wang

Accurately modeling the land surface phenology based on satellite data is very important to the study of vegetation ecological dynamics and the related ecosystem process. In this study, we developed a Sigmoid curve (S-curve) function by integrating an asymmetric Gaussian function and a logistic function to fit the leaf area index (LAI) curve. We applied the resulting asymptotic lines and the cu...

2012
Jing Zhao Jing Li Qinhuo Liu Le Yang

Many parameters, such as albedo, vegetation index and leaf area index (LAI) inversed from satellite images, often get saturated when the surface vegetation cover reaches a certain high level. In order to analyze the saturation phenomena in parameter inversion, we analyze the changing of canopy reflectance and backscattering with increasing of LAI through PROSAIL and MIMICS model respectively. T...

2010
Zhaoming Zhang Guojin He Xiaoqin Wang

Abstract-Leaf area index (LAI) is a key parameter in carbon cycling models of forest ecosystem and acquiring LAI with a high spatial and temporal accuracy is of great importance to improve the performance of carbon cycling models. Remote sensing technology provides a promising and practical way to estimate LAI at a large area with high temporal coverage, and hence, considerable effort has been ...

2006
Torbern Tagesson

Two sites in Sweden are investigated for a potential deep repository of the nuclear waste, the Laxemar investigation area (57°5’N, 16°7’E) and the Forsmark investigation area (60°4’N, 18°2’E). In the characterisation of these sites, development of site descriptive models is an important part. Leaves are the main surface were an exchange of matter and energy between the atmosphere and the biosph...

2006
MINE LANDS Douglas Romig Lewis Munk Todd Stein

Evapotranspiration (store and release) soil covers have been proposed as a means to limit acid mine drainage. Soil water balance models, like UNSATH are commonly used to assess the effectiveness of store and release covers. Plant-related attributes are required as inputs to these models. In particular, UNSAT-H requires leaf area index (LAI) and root length density (RLD) inputs. Published LAI an...

2005
Sampo Smolander Pauline Stenberg

Simulations of the different components of the spectral radiation budget of structurally simple leaf and shoot canopies with varying canopy leaf area index (LAI) were performed. The aims were (1) to test a proposed parameterization of the budget using two spectrally invariant canopy structural parameters ( p and pt) governing canopy absorption and transmittance, respectively, and (2) to incorpo...

2013
E. Boegh R. Houborg J. Bienkowski C. F. Braban T. Dalgaard N. van Dijk U. Dragosits E. Holmes V. Magliulo K. Schelde P. Di Tommasi L. Vitale M. R. Theobald

Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and play a significant role in the global cycles of carbon, nitrogen and water. The purpose of this study is to use field-based and satellite remote-sensing-based methods to assess leaf nitrogen pools in five diverse European agricultural landscapes located in Denmark, Scotland...

2004
Alan G. Barr T. A. Black E. H. Hogg N. Kljun K. Morgenstern Z. Nesic

The seasonal phenology of the leaf area index (LAI) is a major determinant of net ecosystem production in deciduous forest ecosystems. This study describes seasonal and inter-annual differences in LAI in a boreal aspen-hazelnut forest in central Saskatchewan, Canada, between 1994 and 2003, and relates the differences in LAI to annual net ecosystem production (FNEP). A robust method is developed...

Journal: :Journal of economic entomology 2002
Sean Malone D Ames Herbert David L Holshouser

Previous research indicates a correlation between leaf area index (LAI) and yield of full-season soybean [Glycine max (L.) Merrill], which is a single crop planted early in the season. Leaf area index values of at least 3.5-4.0 in the reproductive stages are required for maximum potential yield. It is unknown how yields of double-crop soybean, which is planted late into harvested small grain fi...

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