1.5.4. Spinning up the Satellite Phenology Model

To spin-up the CLMSP model you merely need to run CLMSP for about 50 simulation years starting from arbitrary initial conditions. You then use the final restart file for initial conditions in other simulations. Because, this is a straight forward operation we will NOT give the details on how to do that here, but leave it as an exercise for the reader. See the Example 4-7 as an example of doing this as the last step for CLMCN.

You can also start from a default initial file that is setup as part of the selected compset. Figure 1.5.1 shows spinup behavior for an 1850 SP case that loops over one year of coupler history output for atmospheric forcing (generated from the fully coupled model), initialized with an initial file generated from a GSWP3 atmospheric forcing case. Note that it takes less than 10 years for state variables such as FSH (sensible heat flux), EFLX_LH_TOT (latent heat flux), GPP (photosynthesis), H2OSOI (soil water), and TSOI (soil temperature) to reach a specified equilibrium state (denoted by the dotted lines) due to the different atmospheric forcing. TWS (total water storage) may take a bit longer.

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Figure 1.5.1 SP spinup plot for year 1850. Variables examined are FSH (sensible heat flux), EFLX_LH_TOT (latent heat flux), GPP (photosynthesis), TWS (total water storage), H2OSOI (volumetric soil water in layer 8) and TSOI (soil temperature in layer 10). Generated using …/tools/contrib/SpinupStability_SP.ncl.

Figure 1.5.2 shows spinup behavior for the same case but also changes CO2 to present-day conditions (379ppmv). Again, it takes about 10 years to reach equilibrium.

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Figure 1.5.2 SP spinup plot for year 2000 CO2. Variables examined are FSH (sensible heat flux), EFLX_LH_TOT (latent heat flux), GPP (photosynthesis), TWS (total water storage), H2OSOI (volumetric soil water in layer 8) and TSOI (soil temperature in layer 10). Generated using …/tools/contrib/SpinupStability_SP.ncl.