updated 2-stream scheme available for vegetation canopies

[bernard_pinty@jrc_it]

Remote sensing surface products, such as the albedo, the FAPAR, The Fraction of Absorbed Photosynthetically Active Radiation and the Leaf Area Index (LAI), are operationally available from Space Agencies. Climate models may benefit from these products provided their 1-D radiation transfer schemes effectively represent the 3-D effects implied by the internal spatial variability of vegetation canopies, e.g., the leaf area density, at all scales and resolutions involved (say from 1 to 100 kilometers). Failing to do so leads to inherent inconsistencies between the domain-averaged reflected and absorbed fluxes, and the implied LAI.

We propose a comprehensive approach which introduces a parameterization of the internal variability of the LAI in the 1-D representation of the radiation scheme, called a domain-averaged structure factor, and provides a description of the radiant fluxes fully consistent with the LAI specified by remote sensing. We take this opportunity to revisit and update the two-stream formulations implemented in climate models to accurately estimate the fractions of radiation absorbed separately by the vegetation canopy and the underlying surface.

More information at http://fapar.jrc.it/WWW/Data/Pages/FAPAR_Software/FAPAR_Software_RTModels_two-stream.php

 

[slevis]

You may wish to present your work at the annual CCSM workshop in June. At that time the land model working group can assess whether your code would be of use.

Registration for the meeting is in progress at the CCSM web-site.

Thank you,
Sam Levis