ALBEDO

ALBEDO OPTIMIZATION RELAUNCH

ORCHIDEE simulation configuration :

  • Model : ORCHIDEE 2.2
  • Forcing : CRUJRA v2 (0.5°)
  • PFT maps : ESA CCI LC (1992-2018) aggregated to 0.25° with the old CWT "ESA -> Generic" and the new CWT "Generic -> ORCHIDEE"
  • Period : 1992-2018 (with 10Y-spinup using fixed PFT map for 1992)
  • Used in optimization : 12 monthly maps averaged for 2009-2018

Optimization configuration :

  • Observations : MODIS white-sky albedo (12 monthly maps averaged for 2009-2018)
  • Optimized parameters : 14 vegetation albedo coefficients (alb_leaf_nir or alb_leaf_vis)
  • Background albedo : standard map (optimized in 2016) or original JRC-TIP product (mean value for 2001-2010), one static map, no change during optimization
  • Minimization algorithm : L-BFGS-B
  • At each iteration albedo is calculated offline following the ORCHIDEE formulations and using the outputs for variables :
    • vegetfrac
    • maxvegetfrac
    • tot_bare_soil
    • nobiofrac
    • snow
    • snownobio
    • snowage
    • snownobioage
    • snowdz
    • snowrho
  • During optimization the data are used only from the points where 3 conditions are met together :
    • MODIS has valid data (not masked)
    • ORCHIDEE has valid data (not masked)
    • snow is absent, i.e. ORCHIDEE simulated snow mass is equal to zero (snow = 0)

Using standard background albedo (optimized in 2016)

ALB_NIRPFT2PFT3PFT4PFT5PFT6PFT7PFT8PFT9PFT10PFT11PFT12PFT13PFT14PFT15
prior0.230.180.180.20.240.150.260.20.240.270.280.260.240.24
min0.10.10.10.10.10.10.10.10.10.10.10.10.10.1
max0.30.30.30.30.30.30.30.30.40.40.40.40.40.4
post0.1890.20090.11640.15430.27310.15250.24070.23750.23070.25610.25380.30890.10.2469

ALB_VISPFT2PFT3PFT4PFT5PFT6PFT7PFT8PFT9PFT10PFT11PFT12PFT13PFT14PFT15
prior0.040.040.040.040.030.030.030.030.060.060.060.060.060.06
min0.010.010.010.010.010.010.010.010.010.010.010.010.010.01
max0.050.050.050.050.050.050.050.050.10.10.10.10.10.1
post0.025570.012140.018860.021050.027840.033720.03230.029420.05160.072460.063180.062340.010.01951


Using original JRC-TIP background albedo regridded from 0.01° to 0.5°

ALB_NIRPFT2PFT3PFT4PFT5PFT6PFT7PFT8PFT9PFT10PFT11PFT12PFT13PFT14PFT15
prior0.230.180.180.20.240.150.260.20.240.270.280.260.240.24
min0.10.10.10.10.10.10.10.10.10.10.10.10.10.1
max0.30.30.30.30.30.30.30.30.40.40.40.40.40.4
post0.19240.19590.11420.15890.27480.14470.25610.2340.24590.27990.24880.31790.15370.2634

ALB_VISPFT2PFT3PFT4PFT5PFT6PFT7PFT8PFT9PFT10PFT11PFT12PFT13PFT14PFT15
prior0.040.040.040.040.030.030.030.030.060.060.060.060.060.06
min0.010.010.010.010.010.010.010.010.010.010.010.010.010.01
max0.050.050.050.050.050.050.050.050.10.10.10.10.10.1
post0.02590.027770.023860.02440.018810.028620.037230.010.042540.039810.055390.060460.010.02734