Also known as
Model type Modular
Model part of larger framework
Note on status model
Date note status model
Incorporated models or components:
Spatial dimensions 3D
Spatial extent Continental, Regional-Scale, Landscape-Scale, Watershed-Scale
Model domain Terrestrial, Hydrology, Coastal
One-line model description Landform evolution model
Extended model description A landform evolution model operating at the drainage basin or larger scale. Recent model development has targeted planetary applications.

landscape evolution,

Name Alan Howard
Type of contact Model developer
Institute / Organization University of Virginia
Postal address 1 P.O. Box 400123
Postal address 2
Town / City Charlottesville
Postal code 22904-4123
State Virginia
Country United States
Email address
Phone 434-924-0566
Fax 434-982-2137

Supported platforms
Linux, Windows
Other platform
Programming language


Other program language
Code optimized
Multiple processors implemented
Nr of distributed processors
Nr of shared processors
Start year development 1990
Does model development still take place? Yes
If above answer is no, provide end year model development
Code development status Active
When did you indicate the 'code development status'? 2020
Model availability As code
Source code availability
(Or provide future intension)
Through CSDMS repository
Source web address
Source csdms web address
Program license type Other
Program license type other None
Memory requirements Variable - dynamic arrays
Typical run time hour to days

Describe input parameters Initial elevation file.

File specifying boundary conditions, run time, process options, and parameter values.

Input format ASCII
Other input format
Describe output parameters RAW image files of elevation and shaded relief.

ASCII file of elevations at specified times. ASCII files of other state variables as desired at specified times. Iteration-by-iteration summary file

Output format ASCII
Other output format
Pre-processing software needed? No
Describe pre-processing software
Post-processing software needed? Yes
Describe post-processing software Photoshop to produce movies. Conversions to a variety of data formats.
Visualization software needed? Yes
If above answer is yes
Other visualization software Surfer for topographic maps

Describe processes represented by the model Bedrock fluvial incision (shear stress or sediment flux dependency).

Mass wasting (creep and threshold-limited). Bedload sediment transport & deposition in streams, fans, deltas. Impact cratering, aeolian deposition, lava flows. Flow routing with evaporation from depressions.

Describe key physical parameters and equations Bedrock erodibility, mass wasting diffusivity, bed material grain size, flow hydrologic parameters, relative evaporation rate, cratering size distribution and rate, eolian deposition parameters, etc.
Describe length scale and resolution constraints Variable - targeted towards drainage basin or larger scales. Spatial scale determined by input parameter and run-time specification of array dimentions. Uses rectangular grid cells.
Describe time scale and resolution constraints Variable - Limited by computer speed.
Describe any numerical limitations and issues Runs with grid sizes greater than about 600x600 may require many days on a PC.

Model assumes fluvial streams have gradients determined by steady-state transport.

Depositional stratigraphy not modeled.

Describe available calibration data sets
Upload calibration data sets if available:
Describe available test data sets Example runs for most types of simulation scenarios
Upload test data sets if available:
Describe ideal data for testing

Do you have current or future plans for collaborating with other researchers? Yes, at present primarily in the planetary community.
Is there a manual available? Yes
Upload manual if available: Media:marssim_program.pdf
Model website if any
Model forum / discussion board
Comments Most recent model available from

This part will be filled out by CSDMS staff

OpenMI compliant No but possible
BMI compliant No but possible
WMT component No but possible
PyMT component
Is this a data component
DOI model 10.1594/IEDA/100144
For model version 3.0.0
Year version submitted 2011
Link to file
Can be coupled with:
Model info

Nr. of publications: 7
Total citations: 1301
h-index: 5
m-quotient: 0.17

Link to this page




Nr. of publications: 7
Total citations: 1301
h-index: 5
m-quotient: 0.17

Featured publication(s)YearModel describedType of ReferenceCitations
Howard, Alan D.; 1994. A detachment-limited model of drainage basin evolution. Water Resources Research, 30, 2261–2285. 10.1029/94WR00757
(View/edit entry)

Model overview

Howard, Alan D.; 2007. Simulating the development of Martian highland landscapes through the interaction of impact cratering, fluvial erosion, and variable hydrologic forcing. Geomorphology, 91, 332–363. 10.1016/j.geomorph.2007.04.017
(View/edit entry)

Related theory

Howard, A.D.; 2011. MARSSIM, version 3.0.0.. , , 10.1594/IEDA/100144
(View/edit entry)
Source code ref. 0
See more publications of MARSSIM



Model_help:MARSSIM Documentation that describes MARSSIM subroutines and functions, input and output files, and literature references can be found here: marssim_program.pdf

Input Files

See: marssim_program.pdf

Output Files

See: marssim_program.pdf

Download source code

Accessory MARSSIM programs can be downloaded here:

Example simulations are for a variety of scenarios are generated and can be downloaded below:

  • Accretion
  • Arid_slope
  • Bedrock: (download these 2 files and place in the bedrock folder)
  1. Bedrock