نتایج جستجو برای: leaf area index lai
تعداد نتایج: 1018301 فیلتر نتایج به سال:
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...
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...
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...
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 ...
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...
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...
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...
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...
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...
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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