Search Results

You are looking at 1 - 8 of 8 items for :

  • Radiative transfer x
  • The Cold Land Processes Experiment (CLPX) x
  • All content x
Clear All
Richard Essery, Peter Bunting, Aled Rowlands, Nick Rutter, Janet Hardy, Rae Melloh, Tim Link, Danny Marks, and John Pomeroy

remote sensing algorithms, therefore, often include simple representations of radiative transfer in canopies. Variants of Beer’s law or two-stream approximations are generally used (e.g., Sellers et al. 1986 ; Verseghy et al. 1993 ); these treat canopies as horizontally homogeneous turbid media and only predict the average radiation. The radiative environment beneath real canopies, however, is highly heterogeneous because of sun flecks, canopy gaps, and clearings on wide ranges of length scales

Full access
Rafał Wójcik, Konstantinos Andreadis, Marco Tedesco, Eric Wood, Tara Troy, and Dennis Lettenmeier

retrieval of atmospheric moisture in which the SWE problem is incidental. However, even where there is a motivation to update land surface variables, such as SWE, the assimilation of brightness temperatures ( T b ), rather than derived the SWE products, requires knowledge of snow physical properties because they affect the (surface) emissivity. National Centers for Environmental Prediction (NCEP) operational models currently use the Community Radiative Transfer Model (CRTM), which predicts TOA microwave

Full access
Janet Hardy, Robert Davis, Yeohoon Koh, Don Cline, Kelly Elder, Richard Armstrong, Hans-Peter Marshall, Thomas Painter, Gilles Castres Saint-Martin, Roger DeRoo, Kamal Sarabandi, Tobias Graf, Toshio Koike, and Kyle McDonald

the LSOS consisted of a high sampling density within relatively uniform areas of the LSOS to facilitate a comparison of microwave remote sensing data, radiative transfer models, detailed physical models of the snow and the underlying soil, and ground observations. A network of footpaths was established throughout the LSOS to prevent the disruption of the specific measurement sites. 2. Summary of collected data parameters a. Canopy characterization In the fall of 2001, Cold Regions Research and

Full access
Jicheng Liu, Curtis E. Woodcock, Rae A. Melloh, Robert E. Davis, Ceretha McKenzie, and Thomas H. Painter

) results from the Moderate Resolution Imaging Spectroradiometer (MODIS) snow-covered area and grain size (MODSCAG) model for the Cold Land Processes Field Experiment (CLPX) in the St. Louis Creek intensive study area (ISA) of the Fraser Experimental Forest. MODSCAG combines a radiative transfer model for snow spectral endmembers with a multiple endmember spectral mixture analysis approach in which the number of endmembers as well as the endmembers themselves may vary on a pixel by pixel basis. When

Full access
John Pomeroy, Chad Ellis, Aled Rowlands, Richard Essery, Janet Hardy, Tim Link, Danny Marks, and Jean Emmanuel Sicart

radiative transfer modeling. 2. Variability of shortwave transmission through forest canopies Forested landscapes have a large spatial distribution of ablation energy because this energy varies according to the structural properties of the canopy [e.g., density, Davis et al. (1997) ; leaf area index, Pomeroy and Granger (1997) ]. Transmittance through canopies with relatively small sky view factors can be estimated using the assumption of isotropic scattering by canopy elements; however, it is

Full access
Don Cline, Simon Yueh, Bruce Chapman, Boba Stankov, Al Gasiewski, Dallas Masters, Kelly Elder, Richard Kelly, Thomas H. Painter, Steve Miller, Steve Katzberg, and Larry Mahrt

. The MESMA approach allows the number of endmembers and the endmembers themselves to vary on a pixel-by-pixel basis to accommodate spatial and temporal variability in surface cover. The MEMSCAG model uses spectral reflectance endmembers for snow that are modeled with the discrete ordinate radiative transfer (DISORT) model ( Stamnes et al. 1988 ), with grain radii ranging from 10 to 1100 μ m at 10- μ m intervals. Vegetation, rock, soil, and lake ice spectral endmembers were measured in the field

Full access
D. Marks, A. Winstral, G. Flerchinger, M. Reba, J. Pomeroy, T. Link, and K. Elder

more likely a result of turbulent transfer and conduction between the atmosphere and a radiatively cooling snow surface. Both models and measurements show that turbulent fluxes occur across a snow surface layer of varying thickness, depending on snow density, wind, and atmospheric pressure fluxuations ( Marsh et al. 1997 ; Jordan et al. 1999 ; Essery et al. 2003 ; Massman 2006 ; Massman and Frank 2006 ). Based on the analysis presented here, it would appear that the active layer thickness for

Full access
Nick Rutter, Don Cline, and Long Li

, J. H. G. , and Morris E. M. , 1999 : Incorporation of spectral and directional radiative transfer in a snow model. Hydrol. Processes , 13 , 1761 – 1772 . 10.1002/(SICI)1099-1085(199909)13:12/13<1761::AID-HYP856>3.0.CO;2-Y Groffman, P. M. , Hardy J. P. , Nolan S. , Fitzhugh R. D. , Driscoll C. T. , and Fahey T. J. , 1999 : Snow depth, soil frost and nutrient loss in a northern hardwood forest. Hydrol. Processes , 13 , 2275 – 2286 . 10.1002/(SICI)1099

Full access