= Description of the sub-grid representation =

The following open wiki document outlines proposed developments to the sechiba module that will allow for the separate representation of PFTs (or of groups of PFTs) within each grid square . Please feel free to post thoughts and questions!

'''(link to [https://docs.google.com/document/d/12JEP2tDUaiSdNKKsVs3khUkz4WT4W5gUpUQSnaBv02I/edit sub-grid options in ORCHIDEE-CAN])'''

This developement is motivated in part by research regarding differences in modelled characteristics when the 'mosaic' approach is applied within grid cells. ([https://forge.ipsl.jussieu.fr/orchidee/attachment/wiki/DevelopmentActivities/subgrid/Li%2C%20Arora%20-%202012%20-%20Effect%20of%20mosaic%20representation%20of%20vegetation%20in%20land%20surface%20schemes%20on%20simulated%20energy%20and%20carbon%20balances.pdf Li & Arora, 2012]; [https://forge.ipsl.jussieu.fr/orchidee/attachment/wiki/DevelopmentActivities/subgrid/bg-11-1021-2014.pdf Melton & Arora, 2014]) found that although there were differences of only 5% between grid averaged heat fluxes between the mosaic approach and composite approach are compared, differences of 30-40% were observed for grid averaged NPP, LAI, soil Carbon and vegetagion biomass. For high within-cell heterogeneity, differences were much greater in both instances. The mosaic versus composite effect has yet to be tested in a model on a global scale.


== References ==


[https://forge.ipsl.jussieu.fr/orchidee/attachment/wiki/DevelopmentActivities/subgrid/Li%2C%20Arora%20-%202012%20-%20Effect%20of%20mosaic%20representation%20of%20vegetation%20in%20land%20surface%20schemes%20on%20simulated%20energy%20and%20carbon%20balances.pdf Li & Arora (2012)], 'Effect of mosaic representation of vegetation in land surface schemes on simulated energy and carbon balances'

[https://forge.ipsl.jussieu.fr/orchidee/attachment/wiki/DevelopmentActivities/subgrid/bg-11-1021-2014.pdf Melton & Arora (2014)], 'Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink' 

[http://www.geosci-model-dev.net/9/223/2016/ Ryder et al (2016)], 'A multi-layer land surface energy budget model for implicit coupling with global atmospheric simulations'