’s General Ecosystem Model ( GEM) was written in Borland Delphi for IBM PC compatibles. If you want to make changes to the GEM equations you will need Borland Delphi, otherwise you do not.
Each version of GEM is packaged into a zip file. The zip file contains the full source code, the GEM Windows executable, and sample parameter and driver files. Before running GEM unzip the files into an empty directory.
Unless explicitly stated otherwise, parameter files created in one version of the GEM are not compatible with another version.
Acceptable Use Policy
The software provided on this page has been tested under the Windows NT, XP and 7 operating systems. However, its stability under all conditions cannot be guaranteed. The user assumes all risk for its use.
Downloading and using the software requires that:
- The Principal Investigator is sent a notice stating the model version downloaded.
- The user regularly checks this web site for updated software.
- The Principal Investigator of the model be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications.
- A copy of any resultant publications should be sent to:
Edward Rastetter
Ecosystems Center
Marine Biological Laboratory
Woods Hole, MA 02543
Versions Available for Download
GEM Version 6.4.4.5
Daily GEM with vegomatic
Updated 27 May 2005
Modified fonts, etc so that windows and dialogs size properly on laptops and other aesthetic changes.
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, Update 1.Uses TMS Softwares TAdvstringgrid |
:GEMv6445 |
Relevant Citations: Unpublished |
GEM Version 6.4.4.3
Daily GEM with vegomatic
Updated 28 February 2005
Parameter files created in version 6.4.4.1 should be compatible with this version but the user should check the model output to make sure.
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, Update 1
Uses TMS Softwares TAdvstringgrid version |
:GEMv6443 |
Relevant Citations: Unpublished |
GEM Version 6.4.4.1
Daily GEM
Updated 20 May 2003
Added annual respiration for each tissue, humus C:N and active soil C. Corrected bugs in the append to output file option
Parameter files created in gemv644 are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid version |
:GEMv6441 |
Relevant Citations: Unpublished |
GEM Version 6.4.4
Daily GEM
Updated 15 May 2003
Added annual NPP for each tissue. Added the ability to append to the output file.
Parameter files created in gemv6433 are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid version 2.8.8.0 |
:GEMv644 |
Relevant Citations: Unpublished |
GEM Version 6.4.3.3
Daily GEM
Updated 2 April 2003
Corrected calculation of heartwood litter when heartwood is zero.
Parameter files created in gemv6432 are compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid |
:GEMv6433 |
Relevant Citations: Unpublished |
GEM Version 6.4.3.2
Daily GEM
Updated 24 March 2003
Corrected initialization of three cumulative processes.
Parameter files created in gemv6431 are compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid |
:GEMv6432 |
Relevant Citations: Unpublished |
GEM Version 6.4.3.1
Daily GEM
Updated 18 March 2003
Changed the allocation equations. Updated Et equations. Fixed minor bugs in modelshell.
Parameter files created in gemv642 are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid |
:GEMv6431 |
Relevant Citations: Unpublished |
GEM Version 6.4.2
Daily GEM
Updated 16 December 2002
Added ability to modify parameters from within the chart, to automatically show chart, to run the model to steady state, to change the output offset, and to output only the end of the run.
Parameter files created in gemv641 are compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid |
:GEMv642 |
Relevant Citations: Unpublished |
GEM Version 6.4.1
Daily GEM
Updated 3 December 2002
Changed transport, growth, and litterfall equations to improve model stability.
Parameter files created in earlier versions are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid |
:GEMv641 |
Relevant Citations: Unpublished |
GEM Version 6.3.1
Daily GEM
Updated 2 October 2002
Corrected 7 October 2002
GEM v6.3.0 with correction to N fixation equation
Parameter files created in earlier versions are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid |
:GEMv631 |
Relevant Citations: Unpublished |
GEM Version 6.3.0
Daily GEM
Updated 6 June 2002
Daily model that includes simplified allocation and growth models, inhibition of C and N uptake and fixation. Updated the root growth response and corrected litterfall partitioning equations.
Parameter files created in earlier versions are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid |
:GEMv630 |
Relevant Citations: Unpublished |
GEM Version 3.3.6.5.d
Annual GEM using ACM photosynthesis submodel.
Includes code for hillslope calculations.
Parameter files created in earlier versions are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, update 1 |
:GEMv3365d |
Relevant Citations: Rastetter et al., 2004 |
GEM Version 3.3.6.5.b
Annual GEM using ACM photosynthesis submodel.
Parameter files created in earlier versions are not compatible with this version
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Contains: GEM program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, Update 1 |
:GEMV3365b |
Relevant Citations: Le Dizès et al., 2003 |
AGET - Soil Water Model
Updated 15 September 2000
The AGET model is a daily soil water model currently under development. This version of AGET includes daily submodels of decomposition and photosynthesis.
Parameter files created in earlier versions are not compatible with this version
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Contains: AGET program, source code, sample parameter files and driver files and Word documentation. |
Created in: Delphi 5, Update 1 |
:SoilWater |
Relevant Citations: Unpublished |
This material is based upon work supported by the National Science Foundation under grants #OPP-9318529, OPP-9732281, DEB-9509613, and DEB-0108960 and the Environmental Protection Agency under grants RFQ-RT-00-00107 and QT-RT-00-001667. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the Environmental Protection Agency.