Miscellaneous Changes from Version 4

Several miscellaneous differences in the Century algorithms between versions 4 and 5 are listed below. These differences do not have a significant effect on the simulation results, unless otherwise noted.

• Rooting depth (NLAYPG) is now used in some calculations where in version 4 only the surface layer is used. The effect of this change may be especially evident in the calculation of potential production, which now receives the weighted mean of the maximum plant-extractable water over the rooting depth, rather than just the surface layer.
• Main simulation loop timing fix: In version 4, a misprogrammed increment of a timing loop variable resulted in writing of output one month early. Hence, a request for December output provided results for November in the output file. Version 5 provides the output for the month requested.
• There are new output variables. These are described in the sections with the definitions for the output variables.
• Added fix in calculation of N uptake in soil, so that the monthly symbiotic N fixation amount is not included in soil N uptake. (This fix had previously been included in the gridded Century version.)
• Added the applicable latest changes from the VEMAP and daily FORTRAN versions, including:
  • WoodDeath: Check for available soil water when deciding to drop leaves in deciduous forests. Also added check for winter solstice if trying to drop decidous leaves.
  • AtmCO2Effect: Fix use of step vs. ramp function.
  • InitMonthlyCycle: Added a simple soil temperature lag calculation based upon a warming or cooling trend. (This fix had previously been included in the gridded Century version.) The soil temperature output variable STEMP now contains the new calculation.
• Replaced the random number generator functons with a set of portable functions that are freely distributable. If you use stochastic weather, you will see differences in the precipitation due to this change.
• Day length calculation did not correctly handle the southern hemisphere.

See Also

Obsolete Site Parameters
Obsolete Fixed Parameters
Release Notes