NASA Ames Mars Climate Modeling Group

The History of Mars General Circulation Modeling

60s & 70s

Conway Leovy Jim Pollack

The Pioneers of Mars General Circulation Modeling, from the left Conway Leovy and Jim Pollack

Mars general circulation modeling began in the 1960s when Conway Leovy and Yale Mintz modified the UCLA two level model for conditions appropriate for Mars and used it to study the planet's wind systems, thermal structure, and energetics (Leovy and Mintz, 1969).

Jim Pollack, who joined NASA's Ames Research Center in the early 1970s, recognized the importance of such a tool for NASA's Mars Exploration Program (MEP) and began a collaboration with Leovy and Mintz, that brought the model to Ames, it has continued to evolve and improve ever since. Since those early days, many groups have developed general circulation models for Mars motivated by the increasing number of missions to the Red Planet with payloads capable of measuring the atmosphere. Below is a timeline showing the chronology of these developments.

GCM History Timeline

Here we briefly describe how the Ames Mars GCM evolved to its present state and who the key players were in its evolution.

With Mariner 9's discovery of large topographic relief, Pollack began modifying the model to include spatially varying surface elevation at the model's lower boundary. He added another layer to the model and improved its boundary layer scheme and then used it to successfully predict surface winds at the Viking landing sites (Pollack et al., 1976). With graduate student Paul Greiman, Pollack, Leovy, and Mintz then carefully analyzed the effect of topography on the general circulation during southern winter and found it to force very large amplitude quasi-stationary planetary waves (Pollack et al., 1981).

80s & 90s

By early 1980's it was becoming increasingly apparent that dust in the Martian atmosphere must have a significant effect on the general circulation. Simpler 2-D zonally-symmteric models showed that the absorption of solar and infrared radiation by suspended dust particles could significantly expand and intensify the Hadley circulation, and that this could play a major role in the development of global-scale dust storms (Haberle et al., 1982). During the remainder of the 1980's and early 1990's, therefore, dust radiative heating algorithms were implemented and tested in the model, the number of layers increased from three to thirteen, and many new diagnostic packages were designed. Bob Haberle, who joined Pollack at Ames as a post-doc in 1981, and Jeff Barnes, who came a year later, carried out most of this work.

Many runs were executed and analyzed during this period that ultimately culminated in the publication of papers describing the effects of dust on polar condensation processes (Pollack et al., 1990); the zonal mean circulation (Haberle et al., 1993); and transient and quasi-stationary waves (Barnes et al., 1993; Barnes et al., 1996).

Jim Murphy and Jeff Hollingsworth came to Ames as post-docs in the early 1990s, along with Francois Forget from France to work with Haberle and Pollack to study large-scale dynamics, global dust storm evolution, and polar processes. Murphy implemented a tracer transport scheme into the model that led to the first 3-D simulation of a global dust storm (Murphy et al., 1995). Hollingsworth developed sophisticated dynamical diagnostic routines and discovered the existence of storm zones on Mars (Hollingsworth et al., 1996). And Forget and Pollack carefully analyzed Viking IRTM data to better understand the nature of the polar caps clouds (Forget and Pollack, 1996).

Pollack Rd.

Pollack Road located at NASA Ames Research Center, named after the Mars GCM pioneer Jim Pollack.

Sadly, Pollack fell ill in 1992 and passed away in 1993. Bob Haberle assumed leadership of the effort and continued with Pollack's plan to improve the model's physics packages and stay involved in NASA's Mars missions. During the 1990s the model's radiation code, and boundary layer scheme (see Haberle et al. 1999) were upgraded, and the Ames group began experimenting with a new dynamical core, which included a tracer transport scheme (Suarez and Takacs, 1995). Manoj Joshi, a post-doc in the mid 1990s, implemented the new dynamical core and bounding layer scheme into the mainstram Ames model and used the model to study western boundary currents on Mars (Joshi et al., 1997), as well as the nature of the atmospheric circulation on planets synchronously rotating around M-dwarfs (Joshi et al., 1997).


By the early 2000s the general research trend with Mars GCMs shifted toward multi-annual simulations with tracer transport capability and more sophisticated cloud microphysics and dust lifting schemes.

Tony Colaprete, Franck Montmessin, and Melinda Kahre came to Ames as post-docs during this time to work on these topics. Tony implemented a CO2 cloud convection scheme that greatly improved the model's polar thermal structure (Colaprete et al., 2008). Franck added a cloud microphysics package based on a second-order moment approach to represent particle size distributions. Melinda improved the transport scheme, implemented dust lifting parameterizations, improved the code structure and its efficiency, and began simulating the dust cycle (e.g., Kahre et al., 2008) and how it couples to the CO2 cycle (Kahre et al., 2010).


Today, the Ames Mars GCM effort is led by Jeff Hollingsworth who took over from Bob Haberle in the Spring of 2007. His plans include raising the model top to include thermospheric processes, adding the LMD photochemistry package to study O3 and trace gas transport, comparing the model with MCS data, conducting studies of past climates, and eventually transitioning to a new dynamical core based on more conservative numerics and more generalized grid geometics.

Our tasks are being carried out as a collaborative effort with R. John Wilson at GFDL, Franck Lefevre and Francois Forget at LMD, Dan McCleese and the MCS team at JPL, NMSU graduate students Maylnda Chizek and Bobbie Edmonds, and a host of French students from SUPAREO in Toulouse, France who come to Ames each year in the Spring to perform their internships.