Changes between Version 31 and Version 32 of DevelopmentActivities/ORCHIDEE-DOFOCO


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Timestamp:
01/11/13 15:12:24 (8 years ago)
Author:
mmcgrath
Comment:

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  • DevelopmentActivities/ORCHIDEE-DOFOCO

    v31 v32  
    33== APPROACH == 
    44The two stream radiation transfer model of Pinty et al is implemented in ORCHIDEE. This routine uses leaf scatter and canopy structure to calculate the radiation transfer and as a result albedo can be calculated.  We are also making it into a multi-layer model.  The calculation of the effective LAI now uses the Pgap model of Haverd et al described in their 2012 paper (Agricultural and Forest Meteorology, Vol. 160, pp 14-35) to take the canopy structure into account. 
     5 
     6== TASKS ACCOMPLISHED == 
     7         * Two stream radiation transfer model of Pinty et al is implemented 
     8         * Effecive LAI is now calculated by the Pgap model of Haverd et al described in their 2012 paper (Agricultural and Forest Meteorology, Vol. 160, pp 14-35) 
     9         * A framework capable of using an arbitrary number of canopy layers is in place, although the tests are still not satisfactory 
     10         * The snow calculation has been modified to include snow in the background reflectance of Pinty's scheme, effectively putting snow under the canopy 
    511 
    612== ROUTINES CHANGED == 
     
    1218 
    1319== TO DO == 
    14         * Add snow 
     20        * Differentiate between infrared and visible scattering in the calculation of the snow albedo 
    1521        * Confirm the details of the multi-layering scheme 
    1622        * change the dimensions of the variable albedo to store direct, diffuse, VIS and NIR (the direct and diffuse distinction becomes moot with the current multilayering scheme, as they must be averaged into one value for the background relfection to communicate between the layers) 
    17         * Check the cause of the one day mismatch in between LAI and LAI_eff 
     23        * Check the cause of the one day mismatch in between LAI and LAI_eff...UPDATE: seems like this is caused by the biomass being updated at 1800 s after midnight, while the LAIeff is updated in the slow processes, at midnight 
    1824        * clean code, why is laieff and singang written in both stomate and sechiba? 
    19         * Use single scattering values that change over the course of the year, first testing the min and max values to see if the results are different (and therefore if it's worthwhile to change) 
     25        * Use single scattering values that change over the course of the year...initial tests described below make it seem like this is important 
    2026 
    2127== TESTS == 
     
    2531        * A 20 layer model was tested against the single layer model, giving small differences (a few percent, relative, at midday) 
    2632        * We tried to optimize the single scattering values in the n-layer case to reproduce the average albedo in the 1-layer case, but a simple optimization scheme is only able to make very small gains and takes an order of magnitude more time 
     33        * Inclusion of the new snow albedo gives realistic trends, with the total albedo spiking after snowfalls and showing diurnal variation with leaves are present, but being flat at other times (the solar angle is incorporated through the use of Pgap, which mostly depends on the canopy) 
     34        * I made use of single scattering albedos that Juliane got from Bernard's inversion scheme for 20 tree species, running tests with the min and max values for single scattering albedo and forward scattering efficiency for both VIS and NIR bands...the MUE for the overal albedo varies by 0.01 to 0.04 albdo units depending on the spectrum 
    2735 
    2836[[BR]]