Century and DayCent Version 5 - Release Notes

Century5 (5.5.12), DayCent5 (5.5.17), C5MPI (1.6.4) - Oct 2016

Fixes and Maintenance

DayCent5 soil mineral N: several tweaks to correct mass balance checks. Code for leaching of mineral N cleaned up (same algorithm).
Century5 soil water model: fine tuning transpiration and water budget testing.
DayCent5 soil hydrology: Fixed error where amtTrans accumulator was incorrectly updated in Infiltration. Fixed issue occuring when bottom layer does not dry below field capacity. Array AMTTRANS now accumulates water transfers between soil layers for saturated flow only.
Misc. code cleanup so builds on g++ 6.x with fewer warnings.
Misc. checks for handling very small values.
Tree/shrub: In a savanna system, added check for zero live biomass, at which time the tree/shrub is removed from the system. This allows TREM CCKILL events to transform a savanna system to a crop/grass system.

Enhancements

NetCDF files based upon class IndexLatLonIdNcFile can now have unsorted IDs.

Century5 (5.5.11), DayCent5 (5.5.16), C5MPI (1.6.3) - Aug 2016

Fixes and Maintenance

C5MPI: mods to SiteMgr and SitesLatLonNcFile to reduce memory footprint and enhance parallel reads.
Daymet utilities are now marked as obsolete since they use the old Daymet directory structure. (A new Daymet reader is in the works.)
New algorithm for tree basal area, modified from Century 4.5. BASFCT is used only for small tree biomass when relationship is linear. Basal area is less than linear amount for large aboveground tree biomass.
DayCent5: Transpiration - fixed issue where transpiration from a soil layer was not always removed from the soil water pool.
DayCent5: evaporation and transpiration potential rates use only aboveground dead per Century/Daycent4.5; the bare soil evaporation rate uses both litter and aboveground dead.

Enhancements

New script: SplitCmdLinesFile

Century5 (5.5.11), DayCent5 (5.5.15), C5MPI (1.6.2) - April 2016

Fixes and Maintenance

Weather readers using monthly model-data time mapping upon rewind: CRU reader modified to determine the data extent from the netCDF file; all readers - rewind wraps correctly when model year is any value outside of data year range.
Weather from site parameters: if any PRECIP, TMN2M, or TMX2M parameter values are a missing value (less than -99) the weather site parameters will not be used.
C5MPI: fixed issue in message-send timing for command-lines to work tasks.

Enhancements

C5MPI: Restart file capability writes to a spatial site netCDF file using new "-rf" command-line option. For details see C5MPI.
New utility: CopyFrom100.awk -- Copies a parameter database set from a *.100 file to stdout.
Management events in schedule files can be a repeating event over a range of years. Find details in Management Blocks.

Century5 (5.5.10), DayCent5 (5.5.14), C5MPI (1.5.2) - Oct 2015

Fixes and Maintenance

DayCent5 site parameter checks now verify and fix the values for parameters FSUBLM and STDMP.
Fixed incorrect assignment in DCSiteParamMods::VerifyValues for wilting point.
Site parameters now have numerical limits check upon input.
DayCent5 snow/soil water now correctly balances sublimation when FSUBLIM parameter != 1.0.
C5MPI can use site parameters stored in spatial netCDF file format. See Site Parameters: Spatial netCDF File for details.

Enhancements

CROP management events can now specify a parameter value in the event data. This value replaces the parameter value for that crop. See Management Events for details.
FERT management events can now specify the amount of N, P, and S (parameters FERAMT(*)) in the event for the month. See Management Events for details.
OMAD management events can now specify the amount of carbon (parameter ASTGC) in the event for the month. See Management Events for details.
CopySite utility now can display a progress bar.

C5MPI (1.5) - June 2015

Enhancements

Added a spatial netCDF output format. For details see the sections C5MPI and Examining Simulation Results.

Century5 (5.5.9) and DayCent5 (5.5.13) - April 2015

Fixes and Maintenance

Management: mods to handle schedule files (SCH text format) with varying newline types (e.g. Windows vs. Linux), and trailing spaces after events.

Enhancements

Management: SCH files can have "monthly" or "annual" for the output intervals in blocks, as well as the traditional numeric value.
Management: Blocks in SCH files have events years that repeat the previous year's events using the keyword "repeat" after the block year. Find details in Management Blocks.

Century5 (5.5.8) and DayCent5 (5.5.12) - Feb 2015

Enhancements

New output variables tracking monthly fertilization (N,P,S) transfers to soil pools EFERT(*)
Management schedule files in text format (SCH files) can now have comments after and a block event.
E.g., 1 5 GRAZ GM # moderate grazing from field data
Internal: Configuration information was consolidated from several locations into the main configuration classes. User: More configuration information is written to the log file, and is used in the initialization of output files.
The file WeatherDataPaths.txt can now have an "any" system name, specifying the path if no matching system name if found.

Century5 (5.5.7) and DayCent5 (5.5.11) - Oct 2013

Enhancements

New soils netCDF file format. A soils netCDF file contains a collection of soil profiles expressed in terms of site parameters, in which each soil is identified by latitude, longitude and ID number. See Soils netCDF file.
New site spatial netCDF file format. A spatial netCDF file contains a collection of sites, in which each site is identified by latitude, longitude and ID number. See Site Parameters: Spatial netCDf file,
New site and soils ID management classes to assist with the new files.
New utilities: CopySoil, CopySite. See Utilities.
Added Century5 and DayCent5 command-line option -soil. See Running a Century5 or DayCent5 Simulation.
A log file is now created for each Century5 and DayCent5 simulation. Production of a log is turned off using the "-no-log" command-line option option.

Century5 (5.5.6) and DayCent5 (5.5.10) - May 2013

Fixes and Maintenance

DayCent5: Infiltration better handles long periods of ponded water; and when the wetting front does not reach saturation, there is no infiltration.

Enhancements

Leaching: Added solution pools for organic C, N, P, S leached from the simulation layer: soil and baseflow. Leaching now also occurs in the soil litter layer.
DayCent5: Snow submodel now uses the sublimation site parameter, FSUBLM.
DayCent5Chem added to the source code tree.

Century5 (5.5.5) and DayCent5 (5.5.9) - April 2013

Enhancements

New netCDF file format to contain multiple site parameter sets. Each site has a unique key of latitude, longitude and site ID number.
New Water/Temperature output variables:
EVAPA = annual EVAP accumulator
TRANA = annual TRAN accumulator
RUNOFFA = annual RUNOFF accumulator
STREAMA = annual STREAM(1) accumulator
New Crop/Grass C and Forest C output variables are:
LAI = leaf area index, estimated monthly
LAIMAX = annual maximum LAI

Century5 (5.5.4) and DayCent5 (5.5.8) - October 2012

Fixes and Maintenance - DayCent5

Fertilization issue fixed: If a mgmt schedule has the same FERT option repeatedly, the DB (GetFertilization) does not get called. But the amount to fertilize, as specified in the original FERT event, did not get replenished. Now it is.
Base flow leaching of N,P,S could occur even if no new water flow entered the deep storage. Now there must be flow into deep storage in order for there to be base flow leaching.
Tree growth: Maintenance respiration is now subtracted from potential production before allocations to tree parts are made, as is done in monthly Century.
Nitrification: Conversion of soil ammonium to NO3 is limited to 20% of ammonium.
InitializePools: Burke's Eq. can be negative for small silt and clay fractions. Now provides a minimum of 100 g of SOC.
InitDailyCycle: wt.evap now includes sublimation.

Enhancements - DayCent5

DayCent5 now can read weather data from a netCDF CF-formatted file using an simple grid format. See DayCent5 netCDF file: simple grid format.
CO2 concentration data can now be read from a file. See Enriched CO2 Effects.

Century5 (5.5.2.2) and DayCent5 (5.5.5.3) - March 2012

Enhancements

Added command-line options "-mf" and "-mf?".
DayCent5 now can read weather data from a netCDF CF-formatted file using an indexed format. See DayCent5 netCDF file: indexed grid format.
The following output variables were cumulative over the simulation, but now are annual totals: FERTOT(1-3), VOLEXA, VOLGMA, VOLPLA.

Century5 (5.5.1.15) and DayCent5 (5.5.4.11) - Jan 2012

Fixes and Maintenance

Fall of standing dead, death of roots and shoots, have monthly rates. For DayCent, the rate is modified by the length of the production period (1 week or less).
If an initial tree was not specified in the sch files, but a block planted a tree, relevant initialization code was not called. Initialization is now done for the tree addition after startup.

Century5 (5.5.1.10) and DayCent5 (5.5.4.7) - Sep 2011

Fixes and Maintenance

Grazing: The GRZEFF effect upon production had applied to potential production. But the Holland et al. (1992) curves could not be reproduced for the CPER in the model responses. Changed to apply grazing restrictions to actual production (crop/grass growth). For GRZEFF options 5 and 6, the Holland curves now can be approximated for CPER simulations.
The temperature effect upon potential production: Changed algorithm to the original Paustian algorithm; had been using the VEMAP algorithm.

Century5 (5.5.1.8) and DayCent5 (5.5.4.5) - Aug 2011

Fixes and Maintenance

Fixed bug in a Century4 algorithm which calculated potential production for crop/grasses. The fraction of root C was not recalculated after the root-to-shoot ratio was modified.

Century5 (5.5.1) and DayCent5 (5.5.4) - May-June 2011

Fixes and Maintenance

Fixed bug in a Century4 algorithm which initialized some annual accumulators mid-year. This caused a loss of accumulated amounts for simulations in the southern hemisphere, where the amounts were from the second half of the previous growing season.
Removed the NetCDF 3.5.0 source tree from the IRC source tree. All build files were modified to use the system-installed NetCDF library and development files, which currently should be at version 4.x.

Enhancements

Added output variables to track peak biomass for the growing season:

Variable	Description
BMAXAGL, BMAXAGD, BMAXBG	Annual maximum monthly biomass for crop/grass aboveground live and dead (litter), and belowground components. Units = g C/m2.
BMAXLF, BMAXR, BMAXW, BMAXWD	Annual maximum monthly biomass for tree/shrub leaf + fine branch, root components, aboveground wood, and aboveground dead wood. Units = g C/m2.

C5MPI is a new front-end for Century5 (and soon DayCent5) which runs multiple simulations concurrently on systems that support MPI. C5MPI accepts a text file containing Century5 command-lines, and runs one simulation per command-line, on as many CPUs or cores as is specified.
The algorithm for the soil water effect upon production has been changed to use a logistic curve. See the page Crop and Grassland Submodel to read a description of the algorithm.
Added debug command-line option to Century5: "-d7". This produces an log file of the weather schedule each time it is changed.

Century5 (5.5.0) and DayCent5 (5.5.3) - March 2011

Enhancements

Replaced the weather data code with the Weather Data Framework. The source for this is in source code directory
Ecosystem/Weather/
Added a weather data interface to use the CRU monthly weather data in the netCDF format used at NREL.

For grass simulations, the output variables for C and (N,P,S) returns and removals now are separate for grazing and fire.
Here is a table of the old and new variables for "Crop and Grassland C Output Variables":

Old Variable	New Variables
(both fire & grazing)	Grass Fire	Grazing	Description
CRETA	CRETFA	CRETGA	C RETurn from [Fire \| Grazing] Annually. CRETFA is always zero, since currently fire does not transfer C to system or soil pools.
SDREMA	SDRMFA	SDRMGA	Standing Dead ReMoved by [Fire \| Grazing] Annually
SDRMAI(2)	SDRFAI(2)	SDRGAI(2)	Standing Dead Removed by [Fire \| Grazing] Annually: Isotopes
SHREMA	SHRMFA	SHRMGA	SHoots ReMoved by [Fire \| Grazing] Annually
SHRMAI(2)	SHRFAI(2)	SHRGAI(2)	SHoots Removed by [Fire \| Grazing] Annually: Isotopes

Here is a table of the old and new variables for "NPS Output Variables":

Old Variable	New Variables
(both fire & grazing)	Grass Fire	Grazing	Description
ERETA(3)	ERETFA(3)	ERETGA(3)	E amount RETurned by [Fire \| Grazing] Annually
SDRMAE(3)	SDRFAE(3)	SDRGAE(3)	Standing Dead Returned by [Fire \| Grazing] Annual E amount
SHRMAE(3)	SHRFAE(3)	SHRGAE(3)	SHoots Returned by [Fire \| Grazing] Annual E amount

Modified function PotPlantProdFromSoilH2O so the algorithm behaves exactly like the graph in figure 3.9.
Initialization of day length (hours) in code from Century4 was not well handled, such that southern hemi had an initial value = 24, and northern had 0 hours. Now they initialize to the expected day length for the latitude on Julian day 1.
If a site parameter set has snow > 0, but is much too warm, then the start of growth was delayed, particularly in the southern hemisphere. Fixed this by running the soil water submodel to get rid of the snow before running the soil temperature submodel.

Century5 (5.4.8.15) and DayCent5 (5.5.2.20) - November 2010

Fixes and Maintenance

PartitionResidue: Allowed for partitioning of N, P, S when the donor pool was <= 0. The result was negative values in the donor pool (e.g., BGLIVE(1)). Now partitioning does not occur unless the donor pool is > 0. The transfers to structural and metabolic pools are limited by the size of the donor pool.
Several values used in Assert statements, which check for bounds of variables, were not large enough. Changed to accept reasonable ranges.
Output variable values for EUPPRT(part,element) were written "part" order first, so the variable names did not match the ordering. Now they are written correctly.

Century5 (5.4.8.1) and DayCent5 (5.5.2.1) - March 2009

Fixes and Maintenance

Added to Forest C output variables NEEA and NBPA to accumlate annually the monthly varables NEE and NBP.
Corrected the output variables FERTOT(*) which were storing monthly values; they now store cumulative values.

Enhancements

New R script to read and plot Century5 and DayCent5 output variables. In the source tree at Ecosystem/Century5/scripts/Century5.R

Century5 and DayCent5 Version: 5.5.1 - September 2007

Enhancements

Reorganized Tree and Crop/Grass objects' code providing tighter encapsulation. This is documented in the source code documentation: Ecosystem/Century5/doc/SoftwareDesign/SoftwareDesignNotes.html
Refactored of DayCent potential production so it can accept other models, i.e., photosynthesis. This is documented in the source code documentation: Ecosystem/Century5/doc/SoftwareDesign/SoftwareDesignNotes.html
Refactored of daily time step code (simsom.cpp) to provide capability of hourly time step option.
Refactored management scheduling algorithms and classes so can handle events scheduled for a day within a month. (The schedule file formats were not changed, but remain a planned task.)
DayCent5 has an enhanced soil hydrology submodel that provides smoother and predictible responses. The submodel runs in both hourly and daily time steps with similar behavior and results.

DayCent5 Version: 5.5.0 - April 2007

Enhancements

Updated trace gas submodel to match DayCent 4.5. Added immobilization and mineralization. Updated equations for NO calcs. Added canopy absorbtion of NO.
New monthly output variables for trace gasses: CH₄, NO, N₂O, N₂. These are written to a new output file which has the suffix "-mtg", e.g., "grass-mtg.csv".
Reorganized daily trace gas output variables, so fluxes are listed first, and soil variables are last. Simplified names for flux variables.

DayCent5 Version: 5.4.8.0 - August 2006

Fixes and Maintenance

Modifications to soil hydrology model which provide a better balance of the water budget. Evaporation is now a closer match to the algorithms in Hillel (1977).

Version: 5.4.7.11 - July 2006

Fixes and Maintenance

DayCent5: Modified TDCSoilFlows::FlowNPSintoMineralSoil and FlowNPSfromMineralSoil so check for minimum flow amount. If smaller, return w/out doing the flow. Minimum is currently set to 1.0e-3 g m-2. This produced a speedup of about 2X for g++ build (optimized with -O1 and inline functions) and about 50% for BCB6 builds (optimized with inline functions and auto register variables) simulating c3 grass for 2000 years.
Fix for differences in results from BCB6 vs g++ 3.4 builds of daycent5. Problem was in TDayCentSoil/h2oflux.cpp (TDayCentSoil::SoilWaterFlux) where amtTrans was copied to amtTransDbl. BDB6 w/CARRAY correctly performed the implicit conversion of float -> double for each element in the arrays. g++ did not cast correctly for either BLITZ or CARRAY builds – had to add an explicit cast using the macro CAST_ARRAY_1D.
DayCent5: Add a check in the transpiration calculation which correctly checks that the transpired amount does not exceed available water.
Updated comparisons of Century4, Century5, and DayCent5 for the c3grs site. See Ecosystem/Century5/doc for graphs in PDF format.

Enhancements

R scripts are available to display simulation results using the R package ( http://www.r-project.org ). See the source code directory Ecosystem/Century5/scripts.

Version: 5.4.7.10 - May 2006

Enhancements

Rewrite of import function for Century4 site parameter files ("site.100" files). Now, parameter groups can be in any order. Within a parameter group (e.g., Climate) parameters can be in any order, and import continues if a parameter is missing.

Fixes and Maintenance

Refactoring necessary for building successfully with g++ 4.x.
Code reorganization and refactoring of several base class' for greater conformance to standard C++, and organizational consistancy.

Version: 5.4.7.9 - December 2005

Enhancements

Optimization of the read and management of the parameter databases. Classes refactored for clarity, speed. The source was moved from the Century support directories to the Management source directory.

Fixes and Maintenance

Fixed loop issue where tree removal parameters retrieved the RETF values. The loop index order was incorrect.

Version: 5.4.7 - November 2005

Enhancements

Monthy Century5 and DayCent5

A new command-line parameter -pp path specifies a directory in which to search for parameter files (e.g., crop.100). This path is searched before the default Century path (e.g.,install_dir/bin/parameters/Monthly). See Running Century and CMI with Command-Line Options for details on command-line options.
A site file can now be created at the end of a simulation, based upon the state of the simulated system at that point. A new command-line option -sf file_name specifies the site file name. New classes SiteCreatorBase, CenturySiteCreatorBase, MCSiteCreator, and DCSiteCreator implement this feature. See Running Century and CMI with Command-Line Options for details on command-line options.
New page in the reference: Running a Century Simulation to Equilibrium
The algorithm for nutrient limitation uses only the fine root and leaves of trees for determining the upper limit on the (N,P,S):C ratio.
In restriction of production algorithms, the C-to-biomass conversion factor constant was 2.5 for all parts. Now it is 2.0 for tree parts other than fine root and leaves.
Adjusted the timing classes so monthly Century agrees with DayCent in the floating-point time for output. In floating-point time, January 2000 = 2000.083; December = 2001.0.
Weather data files and site parameter files (Century4 text-format) can now have comments - lines that start with the characters: ; ! # // (double-slash).
Site parameter definitions NetCDF file now stores the parameter set titles.
Site parameter validation is enhanced. Validation and fill of "missing values" now occurs when the configuration object is built, rather than in the Century model. Messages of actions are written to the user's output, or if CMI is in use, to the message window. A description of the actions taken by the validator objects is described in the new page Site Parameters Validation.

Century Model Interface

Includes a major refactoring of the Site Parameters editor (a long time in the works, and a long time needed). Now it can edit both monthly and daily site parameter sets.

Utilities

New utility: DailyWthr2MonthlyWthr - Creates a monthly weather data set from a daily weather data set.
New utility: DailyWthr2SiteParams - Creates a site weather parameter set from a daily weather set. This can be pasted into a site parameter set (e.g., site.100 file).

Fixes and Maintenance

Transpiration is restricted to rooting depth layers. For crop/grass systems, this is the current value of NLAYPG. For tree/savanna systems, this is the depth of the soil profile.
Century5: Evaporation is restricted to the simulation depth (nominally 20 cm). (DayCent5 has a flux-based algorithm that operates across the entire soil profile.)
Century soil classes: Minor optimization of a few functions to prevent excessive memory allocations.
Parameter database files: Added detailed error messages for problems reading the parameter database files (e.g., crop.100).
Calculations involving the layered soil and soil profile organic C distribution have better error messages and more robust recovery from errors and poor soil parameterization.
The class for handling the parameter databases (e.g., crop.100) now has full error handling and recovery.
Century Model Interface: Misc. modifications as needed to implement the same new and modified features as described above for Century5 and DayCent5.

Version: 5.4.6 - February 2005

Fixes and Maintenance

Monthly Century and Century Base Classes

Fixed issues with the -f and -fm command-line arguments.
Added additional diagnostic messages when site parameter-related errors are generated.

Version: 5.4.5 - November 2004

Fixes and Maintenance

Monthly Century and Century Base Classes

Harvest volatization of N: Previously, the cumulative amount for the month of volatized N was being removed from the aboveground biomass. Now, just the amount volatized for that harvest event is removed from the biomass.
Water submodel: Fixed an imbalance which occurred at low PET; a minimum PET value is then used for transpiration calculations, but was not saved for use elsewhere, where the ~zero PET value was used. This directly affects the calculation of CGRAIN, where with the zero value, small negative values of CGRAIN were calculated.
Snow submodel: Liquid remaining in the snow (SNLQ) when the snow melted was not always transferred to the water entering the soil profile. Now it is.
Available water for plants was affected by limitations in the soil layer homogenization algorithm. This algorithm is triggered by cultivation, when a depth of homogenization of the surface soil is estimated from the intensity of cultivation. Previously, when the depth would cause a soil layer to be divided into two layers, the thickness of the divisions was not a restriction. Very thin layers caused havoc with the water submodel. Now, the minimum thickness of a layer division is 0.5 cm.
Potential production: The effect of soil water content on potential production suffered from the problems described above. Now it works well using the depth of roots (NLAYPG) for the amount of soil water. The water amount is now calculated using the plant-available water content over that depth, rather than the total water.
The depth of roots, NLAYPG, can vary depending upon changes in the number of layers. The rooting depth is stored internally, and is used to recalculate NLAYPG as needed.
Added various minor fixes related to floating point comparisons in assertions (internal checks on the reasonableness of values).

Version: 5.4.4 - August 2004

Enhancements

CMI Site Editor

Added a button to "Clear Set". This sets all parameters in the currently displayed parameter set to zero.
Added a checkbox for "read-only" status. When checked, the parameter values cannot be modified.
Minor modifications to the layout of the dialog.
More robust handling of new and empty site sets.

CMI Management Editor

Minor modifications to the layout of the dialog.

Simulation Output File Dialog

A new output configuration dialog replaces the multiple simple dialogs previously used to configure the output file base name and file type.

Century Command Line

Added options -f and -fm to specify the location and name of the fix.100 file to use for the simulation. For more details, see Running Century and CMI with Command-Line Options.
Classes and functions affected:
TCenturyCmdLine, TCenturyConfigBase, TCenturyConfig, TDailyCenturyConfig, TEventDBList, TEventOptionSet
Updated HTML documentation describing the command-line options.

Fixes and Maintenance

Monthly Century

Fixed read of weather files bug, in which weather file was "stuck" at the first record. (Due to a temporary debugging change to the code, which mistakenly was not removed.)

CMI Site Editor

Fixed memory-corrupting attempt to display unusually large parameter values.
Fixed initializion of parameter values when "New" button is pressed. Improper initialization was causing crashes or exceptions.
Misc. minor code cleanup and performance enhancements.

Layered Soil Framework

Fixed improper initialization of default soil properties in soil layered component classes, causing unwanted zeroing of by-layer values.
Some speed optimization of calculations over depth ranges.

Version: 5.4.3 - October 2003

Enhancements

CMI

Now built with V GUI library version 1.90a.
A tabbed-window toolbar is displayed under the menu bar, to provide convenient window access.
Management Editor: Define Blocks: Choose Event Additional Data button:
The radiobutton dialog now pre-selects the radiobutton matching the current value of the Additional data field.
Management Editor: Simulation Information: Initial System:
The "Select" buttons for crop/grass and tree display a list of available crop, grass, and tree types from which to choose the initial system.
Added a popup menu accessable with a right-mouse button click on one of the windows in CMI. The menu has "Copy", "Change Font" and "Exit" selections.

Fixes and Maintenance

Command-Line Arguments

New base class manages arguments as a series of options (1 to N arguments each) rather than as a simple array of strings.
Century's command-line class is rewritten to use the new base class.
Functions accessing command-line arguments were modified to use the new classes.

Misc.

Fixed potential memory leaks in the site parameters class, and the V GUI library.

Version: 5.4.3 - September 2003

Misc. Modifications

User Preferences:

Opening and reading a "user preferences" INI file now works correctly.

CMI

Compiler flags are used during the project build to force correct use of Microsoft Windows 98/ME common dialog boxes when built with Borland C++ Builder 6. The flags, specified when building the V GUI library, are:
WINVER=0x0400 _WIN32_WINNT=0x0400
Improved error handling when reading and importing site and management.

Installation program

System requirements modified to accept a minimal Microsoft Windows 98 operating system and hardware.
Installation and executables were tested on the following Microsoft Windows systems:
- 98 SE
- 2000
- XP Professional

Century Classes

Repeated simulation runs of the same configuration now are re-initialized correctly.

Version: 5.4.2 - September 2003

General Comments

Version 5.4 contains a tremendous number of structural changes to the Century source code. Our task of combining the monthly and daily models into a stronger object-oriented design is largely complete. The Century source code is now part of the source code structure for the new IRC model using the Grid-Cohort Framework.

Significant new features since the last release include

layered soil mineral N, P, and S,
better error handling throughout,
more robust importation of Century4 site and management files,
update reference document.

The source code builds and runs in both the latest Borland and GNU C++ compilers, and so should run in any environment and operating system for which those compilers are available. We routinely test in the following compiler/systems: Borland C++ Builder/Microsoft Windows; GNU g++/Cygwin; GNU g++/Linux.

New or Enhanced Algorithms

Completed implementation of complete TCenturyBase. Most common elements of monthly and daily Century (classes TCentury and TDayCent) have been moved into class TCenturyBase.
Importation of Century4 schedule files: Error checking has been greatly enhanced. Detailed messages provide location information for import problems.
The site parameter classes have undergone a major refactoring, providing better encapulation, division of tasks, and future extensibility.

Fixes and Maintenance

Class TCentury

The relative water contents supplied in the site file were overwritten at the start of a simulation by the calculation using the wilting point and field capacity for each layer. This is fixed so the RWCF(*) are not calculcated at the start unless all values are zero.
Has a large number of fixes, and issues found during code reorganization.

Physical Soil-related Classes

Corrected storage of deep soil water storage, so it isn't overwritten, and is placed in output variable ASMOS(10) per the Century reference manual.

CMI

Upgraded to use the modified class interfaces for site and management.
Several misc. bugs have been fixed.

Miscellaneous

The user preferences class, TUserPref, now adds the extension "ini" to a user preferences file name, if no extension is provided. Fixed a memory leak, where a list of strings was not deleted.
Installation of the Century model's files puts the template and parameter files into the install path, in the subdirectories template and parameters, respectively. These two subdirectories are now further subdivided into Monthly and Daily subdirectories, in order to accomodate the different sets of files required for the monthly and daily versions of Century.

Version: 5.4.0 - July 2002

New or Enhanced Algorithms

Miscellaneous

New new command-line option, "-t0", to turn OFF writing output files.

Class TCentury

At end of each simulation year, the bulk densities and thicknesses of the soil layers encompassed by the simulation depth are recalculated according to the change in the annual mean value of monthly SOMSC. See the section Layered Soil Submodel for details.
The mineral nutrient storage (N, P, S), previously stored in fixed layers (an unmodified relict from Century 4) are now layered components of the physical soil structure. Transfers between the simulation layer pools and these soil mineral nutrient pools account for the layers spanning the simulation depth, rather than surface layer only.

Physical Soil-related Classes

Conversion functions for different units of SOM and SOC are provided in TSoilBase. Classes TCenturySoil, TSoilCDistribution, TDeposition, and TErosion now use these new functions.
Functions for estimating the change in bulk density as the soil organic C content changes are provided in class TSoilBase.

Fixes and Maintenance

Class TCentury

Output for ASMOS(*) and MINERL(*, *) now properly put the deep store values in the 10th element, i.e., ASMOS(10) and MINERL(10, *).
Now checks for a soil thickness (from the site parameters) that is less than the minimum thickness for the simulation layer (20 cm).
Checks for a soil thickness that is equal to the simulation layer thickness. In this case, the lower soil pools are not used, and the algorithms which require more soil are not used - C distribution in the profile, and erosion.
Phosphorus is now correctly transferred between the mineral, secondary, and parent P. See the section Phosphorus Submodel for details.
Forest C output variable, TCREM, is now an annual accumulator, rather than cumulative over the simulation.

Century Model Interface

Site Editor: Fixed several issues involved in accessing site parameter files and replacing the displayed site parameter file.

Miscellaneous

TLowerSoil, TCenturySoil, TSoilBase: Misc. fixes for minor issues found in portability testing.

Version: 5.3.2 - November 2001

New or Enhanced Algorithms

Command Line Options

New command line option " -i filename ", where filename is the name of an initialization file. The default name is " century.ini " in the current path.
Both the command-line version and CMI (e.g., in MS Windows, century.exe and CMI.exe respectively) accept command-line arguments. For instance, you can modify your MS Windows shortcut to CMI to include your initialization file. Likewise, on UNIX or Linux systems, you can create an alias which runs CMI with your initialization file.
Removed command-line option "-dn" which displayed default file names. These default names are now determined in class TCenturyConfig, but are not available at the time the command-line is parsed.

Century Model Interface

The Management Editor's Define Blocks page now provides a popup list of event options for those events which have associated parameter databases.

class TCenturyConfig

New class to contain a complete configuration for a simulation. All initialization of input (site, management, output, etc) is now external to the Century model and class TCentury.
Modified classes TCentury, TApp and the GUI classes, and function main to use this new class.

Fixes and Maintenance

Class TCentury

Fixed bug in reading organic matter input parameter ASTREC.
Fixed bug in reading of Century 4 schedule file which uses CO ₂ effects.
Additional modifications to help build a common source tree with daily and gridded versions (including new base classes TEcosystemModelBase, TCenturyBase, TOutputBase, TCentOutFileBase).

Parameters Database Files

The parameter databases store options for a specific event (e.g., CROP event or FIRE event). The parameter database list have been abstracted into a new class to manage the list. This will allow future features for selective specification of parameter database sets by the user, and provides for centralized management of the database.
Class TCentury: The Century model class now receives a parameter database list object when instantiated. Previously the class opened each database as needed, and managed the list internally.

Century Model Interface

User Preferences dialog: Width of the project, site, and management path fields is larger.
Site and Management Editors: Several improvements, including adding Century4 files to the "Open" button file filters.
TModalDialog base class: Better positioning of large dialogs..

Version: 5.3.1 - June 2001

General Comments

This release has a substantial number of modifications over version 5.2, including many bug fixes, enhancements to the object-oriented design of the code, and implementation of design changes to allow for swapping of simulations. The design goal is provide Century and its supporting submodels with a "pluggable" architecture, so submodels can be changed easily, and so Century can be plugged into other model architectures.

Fixes and Maintenance

Class TFlow

Class TFlow has been rebuilt using containers and algorithms from the the standard C++ library.

Class TSoil

Class TSoil has been replaced by a new set of classes which more easily allow for extensibility of the physical soil. These classes are named TSoilVDCompBase, TSoilPool, TSoilProperty, TSoilCompList, TSoilLayer, TSoilBase.

Class TCenturySoil

TCenturySoil has been rewritten to utilize the new set of soil classes, and is derived from class TSoilBase.
Utilizes a new class TSoilCDistribution which calculates a curve estimating the distribution of the density (g cm ^-3 ) of soil organic C throughout the soil profile. The parameters for this curve are based upon (1) the current C density in the simulation layer, (2) the initial value or last estimated value of the lower soil C pool, and (3) the depth of the soil profile.
Minor cleanup of the soil water bucket submodel.

Classes TLowerSoil, TErosion, and TDeposition

These classes have been modified to use the new version of class TCenturySoil.
These classes no longer modify the physical soil, only the simulation pools.

Class: TCentury

The netCDF template file for the output variables' definitions had the MINERL() ordering sorted first by element, then by layer. Fixed so that sorting is first by layer.
Modification of several member functions to utilize the new soil class, TCenturySoil.
Leaching of organic C is now determined from water flow from the bottom of the simulation layer rather than from "layer 2" or "30 cm depth" as in version 4. Organic C leaching is now encapsulated in a new member function LeachOrganicC.
New output variables: soilDepth , lhsomtc and somtpc .
Increased code readability with several boolean functions.
Fixed bug in which N volatility fixed parameter vlosse was modified in member function DeathOfShoots.
Encapsulated the system type information in a new class TPlantSystemType.
Encapsulated the site geographic and non-weather surface environment in a new class TSiteEnvironment.
Encapsulated the microcosm calculations in a new class TMicrocosm.
Encapsulated the canopy variables and functions in the new class TCanopy.
Corrected setup of microcosm simulations such that (1) temperature is constant, and read from the site parameters; (2) rainfall and irrigation is always zero; (3) the soil water submodel is not used so that the soil water content is constant.
The parameter databases are now stored in memory rather than read at each request. This results in a substantial speed increase of simulations, at the cost of increased memory requirements.
Calculation of whether or not the number of hours in the day are increasing or decreasing fixed so that when current and previous day lengths are equal, no change in the direction occurs.
Calculation of the day length now accounts properly for the southern hemisphere (site parameter SITLAT < 0).
Fix in uptake of N, P, or S so P and S uptake is correctly calculated.
CO ₂ effect ramping function calculating intermediate concentrations did not account for end of the year, at which time no ramping is needed. Now the CO ₂ concentration uses the final value.
Added new event and associated function to provide for external events. This event calls an external function provided by the main program unit or the function which created the Century object. Added the member function UseExtEventtFunction to specify this external function.
Encapsulated all asynchronous functions and variables in a new class, TAsynchFunctions.

Graphical User Interface

Management Editor: Microcosm now has its own entry fields.

Version: 5.2.1 - June 2000

Class: TCentury

Added additional functions to access output variables.

Version: 5.2.0 - May 2000

New or Enhanced Algorithms

New class: TCenturySoil

Derived from TSoil, contains Century-specific soil functions, including the water bucket model.

Weather data (class TWeather)

Replaced the random number generator functons (which were from the book Numerical Recipies) with a set of portable functions that are freely distributable.

Class: Import of Century4 schedule files.

Block definition descriptions are now prefixed by the block number.

Century Model Interface

Added a simple toolbar of buttons for "Quick Steps" to configuring and running a simulation.

Fixes and Maintenance

Class: TCentury

Soil organic matter percent (OMPC) is now updated at the end of each simulation iteration and after erosion and deposition. This is needed in order to update variables dependent upon soil texture and OMPC, such as field capacity and wilting point (depending upon the value of the site parameter SWFLAG).
The mean maximum plant-available water content (field capacity minus wilting point, calculated as a weighted mean by layer thickness) used for the determining the potential crop and tree production is now calculated over the rooting depth. In Century 4, this is only calculated for the surface soil layer, irrespective of layer thickness.
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.)
Function OutputVariables: Fixed bug in the calculation of the output variable ADEFAC, which was a remnant of the conversion of some very bad FORTRAN (Imagine!) to C++.
The water bucket model was moved into a new class TCenturySoil, which is derived from class TSoil.
Increased exception-robustness through the use of auto_ptr for the dynamically-allocated data.
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 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.
Site parameter and internal variable, NLAYPG, the number of layers available for plant growth, is now updated when any change to the physical soil occurs, including as erosion and deposition. It is limited to the range 1-9, and will not exceed the number of soil layers.
Further cleanup of the water submodel code, which contained much spaghetti inherited from the FORTRAN version.

Weather data (class TWeather)

Rewrote the algorithm for reading weather data files. The original was a holdover from the FORTRAN code. The new algorithm is predictable and easy to understand.
Changed algorithm to replace missing values (-99.99) for temperatures in the weather file and the site parameters. The algorithm is now:
(1) If the site parameter temperature value is valid, use it.
(2) Otherwise, estimate a value using linear interpolation or extrapolation.
(3) If the estimate is not available or reasonable, then use the mean annual minimum or maximum temperature.
Modified the precipitation algorirthm for replacing missing values in the weather file and the site parameters. Previously a stochastic value was generated, as described in item 2 below.
(1) If the site parameter precipitation value is valid, use it.
(2) Otherwise, generate a stochastic value based upon the standard deviations and skewness values from the site parameters.
Fully encapsulated the weather class. It is now completely independent of the Century code.

Class: TSoil

Fixed bug in the calculation of weighted means of properties, and encapsulated duplicated code in member functions.
Changed dynamically-allocated member arrays to be of standard library class vector , and modified code to use them appropriately.
Additional improvements to the erosion and deposition algorithms, especially in the area of managing soil water contents.
Some functions which are specific to the Century model were moved into the new derived class TCenturySoil.

Class: TSiteEditorDlg (the site parameter editor)

Fixed bug in which a site parameter set which has been read from a file into the site editor was not copied to the permament site parameter set.

Century Model Interface

Fixed several minor but irritating quirks of the GUI code.
Built CMI for Microsoft Windows using the latest version of the V GUI library (1.24).

Documentation

HTML Help pages - added much of the online Century 4 manual, with some minor modifications to reflect version 5.

Version: 5.1.0 - June 1999

Class: TNcFile (base class for netCDF files)

Rewrote most of the function CreateFrom to fix inconsistancies.

Utility: ef2cvs

Converts an erosion output file in netCDF format, to a text file in CSV (comma-separated values) format, for import into a spreadsheet program.

Class: Output variable classes

Added the management scheme and site file names, and the site parameter set description to the output files.

Class: TWaterTemp (output variables for water and temperature)

Added the output variable "SIMDEPTH", which records in each output record the depth of the simulation layer in cm. This variable is initialized to the value of the fixed parameter EDEPTH (20 cm), and will only be altered by erosion or deposition events.

New classes: TLowerSoil, TDepEroBase, TErosion, TDeposition, TNcErosionFile

Completed the initial version of these new classes.

Class: TMgtDlg (Management editor dialog)

Activated the entry fields and browse buttons for the erosion and depostion files.

Class: TCentury

Function RunSimulation: Added exception handling for failure upon read of intial crop tree parameters.
Function Schedule: Added exception handling for failure upon read of event parameters.

Class: TSimTime

Corrected a problem in Century output timing.

Class: TManagementScheme

Enhanced error messages upon import of Century 4 schedule files.

Class: TSiteParameters

Allowed import of Century 4 site parameter files to accept parameter names that are not enclosed in single quotes.
Fixed bug in import of Century 4 site parameter files.
Enhanced error messages upon import of Century 4 site parameter files.

Class: TWeatherVars

Enhanced reading of the weather file with better error messages.
Made "file rewind" requests more robust (less susceptable to compiler idiosyncracies).

Version: 5.0.x

Apr 1999

Class: TApp

Function RunSimulation: Now closes the progress dialog when execution is stopped prematurely, either through the "Cancel" button or when an exception is generated.

Class: TCentury

Added notes on using C++ inheritance to create a custom version of the Century class.

Mar 1999

Class: TMgtDlg (Management editor dialog)

Fix problem in the display of simulation description.
Added controls, events, functions to select the files for ¹⁴ C input data, erosion output data, deposition input data to the Simulation Information dialog.

Class: TNcFile (netCDF file base class)

Added a member variable to store the netCDF file version, applicable to all Century netCDF file types.
Added functions to "set", "get", and "check" the file version.

Class: TSiteParameters, TNcSiteParameters, TSiteFromLibDlg

TSiteParameters, TNcSiteParameters: Added code to read and write the editor name and edit date in the site parameter netCDF file.
TSiteFromLibDlg: Added display of the editor name and edit date in the summary panel.

Feb 1999

Class: TCentury

Made default values to be TCentury static member constants.
Modified the soil water submodel and all depth-dependent calculations in the decomposition functions to use the new TSoil class.
TSimTime class finished: data and functions for simulation time encapsulated.
Added command-line option to display the execution time of the simulation.
Added a deposition event to the management scheduling.

Class TSoil, TLowerSoil, TErosion, TDeposition (incomplete), TNcErosionFile

New classes for implementing the new erosion and deposition submodels.
TLowerSoil implements the lower layer element pools as a source and sink for the simulation layer pools at the surface, as the simulation layer undergoes erosion and deposition.
TSoil implements a layered physical soil, containing vertically-differentiated layers unique in texture, bulk density, and water content.
TErosion and TDeposition implement erosion and deposition functions. TNcErosionFile manages a file of erosion values, written during erosion events, and read during deposition events.

Class: TDefaultPaths

New class which encapsulates management of default paths for parameter and management files, parameter and management templates, and parameter definition databases.

Class: TNcFile (netCDF file base class)

Added member variable for netCDF file types in the file ncftypes.h.
Added functions to "set", "get", and "check" the file type. Upon creation of a Century netCDF file object, automatically compares the requested type to the type specified in the disk file.

Class: TVerifyMgmt

New class - originally was part of class TMgtDlg, the management editor. Extracted all verification functions into their own class.

Utility: ncfilelist
A command-line utility to list the names and types of Century netCDF files in the directory in which it is run.

Jan 1999

Class: TCentOutFileBase, TCentNcFile, TCentSprShtFile

Added classes which encapsulate Century output:
TCentOutFileBase is the base class for all output files.
TCentNcFile produces netCDF output.
TCentSprShtFile produces CSV (comma-separated values) output for input into spreadsheet and word processor applications.

Class: TCentury

Modified constructor args to utilize new output class.
Modified function "wrtbin" to use new output class;
Discarded the function "detiv", which in Century 4 initialized output files.