2007
| Title: | Sensitivity of Simplified Venus General Circulation Models to Numerical Parameterizations |
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| Authors: | Lee, C.; Richardson, M. I. |
| Affiliation: | AA(Division of Geological and Planetary Sciences. California Institute of Technology, 1200 E. California Blvd M/C 150-21, Pasadena, CA 91125, United States ; lee@gps.caltech.edu), AB(Division of Geological and Planetary Sciences. California Institute of Technology, 1200 E. California Blvd M/C 150-21, Pasadena, CA 91125, United States ; mir@gps.caltech.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2007, abstract #P33B-1306 |
| Publication Date: | Dec 2007 |
| Origin: | AGU |
| Keywords: | 3319 General circulation (1223), 3346 Planetary meteorology (5445, 5739), 3389 Tides and planetary waves, 6295 Venus |
| Abstract Copyright: | (c) 2007: American Geophysical Union |
| Bibliographic Code: | 2007AGUFM.P33B1306L |
| Abstract: | General circulation models (GCMs) of the Venus atmosphere are currently forced using only simplified parameterizations of the radiative forcing and boundary conditions, such as those discussed in Yamamoto and Takahashi (JAS, 2003) or Lee, Lewis and Read (JGR, 2007). Using these parameterizations, suitable dynamical cores produce a qualitatively realistic circulation with super-rotation and transient planetary waves. The quantitative accuracy of the GCMs varies with dynamical core and the particular numerical parameterizations employed. However, all current GCMs exhibit sensitivity to the numerical parameterizations used to describe the behavior of the boundary conditions and the sub grid-scale eddy activity. These parameterizations are often used to reduce the grid-scale noise and unwanted propagating waves caused by discretization in the models We discuss the response of the numerical cores used in a number of simplified Venus GCMs using their various boundary layer and sub grid-scale parameterizations, and forcing with the radiative parameterizations outlined in Lee, Lewis and Read (JGR, 2007). The numerical cores tested include the PlanetWRF model (Caltech/NCAR), FMS (GFDL/NOAA) and HadAM3 (Oxford/Hadley Centre). We also discuss a possible physical interpretation of the sensitivities we have investigated and suggest corrections to the parameterizations used in these simplified GCMs. These corrections should provide more physically reasonable parameterizations for the thick Venus atmosphere, and in turn reduce the sensitivity to the numerical parameterizations such as the horizontal hyper-diffusion used to damp grid-scale waves, or the Rayleigh friction used to damp vertically propagating waves. |
| Title: | Some Coolness on Martian Global Warming and Reflections on the Role of Surface Dust |
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| Authors: | Richardson, M. I.; Vasavada, A. R. |
| Affiliation: | AA(Caltech, 1200 E. California Blvd, Pasadena, CA 91125, United States ; mir@gps.caltech.edu), AB(JPL, 4800 Oak Grove Dr, Pasadena, CA 91109, United States ; ashwin.r.vasavada@jpl.nasa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2007, abstract #P31D-05 |
| Publication Date: | Dec 2007 |
| Origin: | AGU |
| Keywords: | 1605 Abrupt/rapid climate change (4901, 8408), 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513), 5445 Meteorology (3346), 5464 Remote sensing, 6225 Mars |
| Abstract Copyright: | (c) 2007: American Geophysical Union |
| Bibliographic Code: | 2007AGUFM.P31D..05R |
| Abstract: | Recent comparisons of global snap-shots of Mars' surface taken by the Viking and Mars Global Surveyor (MGS) cameras have been used to suggest that Mars has darkened, and hence has warmed, between the 1970's and 1990's. While this conclusion is not supported by more quantitative analysis of albedo data, the idea of Martian darkening and warming has found its way into the terrestrial climate change debate. Through blogs and other opinion pieces it has been used, both amusingly and disturbingly, to argue that Mars' apparent natural warming should alleviate our concerns about anthropomorphic climate change on Earth. Relating planetary research results to terrestrial analogs is instructive and promotes public understanding, but this example provides a cautionary tale of misinterpretation in this age of politicized science. The dust cycle is the dominant short-term component of the Martian climate. The atmosphere is strongly forced via dust's modification of atmospheric radiative heating rates, while dust loading displays dramatic interannual variability, from background opacity to aperiodic global dust storms. Until recently, the atmospheric component of the dust cycle was better documented than the surface component (which on Mars can be gauged via albedo). But now thanks to the combination of regional imaging, spot thermal infrared spectra, and spot short-wavelength photometry sampled at synoptic time and length scales by MGS, a rich new view of the relationship between specific meteorological phenomena and the patterns of surface dust is emerging. Seasonal cap winds, local, regional, and global dust storms, and monsoonal circulations all redistribute surface dust on large spatial scales, while dust devils are surprisingly shown to be insignificant. Rapid and widespread albedo modification is accomplished by storms that darken relatively bright regions through dust removal, and deposit dust upon largely dust free areas, brightening them. (It is not possible with existing data to infer dust deposition or erosion in perennially dusty areas.) However, most of the dust deposited on darker regions is removed within one Martian year. This rapid cleaning suggests that darker areas retain their dust-free albedo over decadal time scales because any dust deposited there can be eroded at commonly experienced wind speeds. Bright regions recover more slowly, sometimes requiring several martian years. The depletion of these dust sources in some years may play an important role in the interannual variability in dust storm occurrence and intensity by introducing a multiyear "memory" into the system. The observation of the 2001 global storm and its wake allows predictions to be made for the recovery following the 2007 global storm: the southern hemisphere should retain a transient brightening until after the seasonal cap has advanced and retreated. The MGS data show that albedo is a dynamic and evolving meteorologically and climatologically active variable, not a static boundary condition. Overall, the major story that albedo has to tell is one of major dust storms and recovery from them &150; not of secular changes &150; and that the changes are mostly cyclic such that surfaces tend to return to their pre-storm albedos. We speculate that this system of fine balances is dynamically controlled, such that interannual occurrence of dust storms and the partial dust coating of the surface should be robust against the expected large changes of orbital parameters throughout Martian geological history. |
| Title: | Non-condensable gas in a Mars General Circulation Model |
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| Authors: | Guo, X.; Richardson, M. I.; Newman, C.; Sprague, A. L.; Boynton, W. V. |
| Affiliation: | AA(Division of Geological and Planetary Science, California Institute of Technology, MC 150- 21, 1200 E. California Blvd., Pasadena, CA 91125, United States ; xin@gps.caltech.edu), AB(Division of Geological and Planetary Science, California Institute of Technology, MC 150- 21, 1200 E. California Blvd., Pasadena, CA 91125, United States ; mir@gps.caltech.edu), AC(Division of Geological and Planetary Science, California Institute of Technology, MC 150- 21, 1200 E. California Blvd., Pasadena, CA 91125, United States ; claire@gps.caltech.edu), AD(Lunar and Planetary Laboratory, Lunar and Planetary Laboratory, Tucson, AZ 85721, United States ; sprague@lpl.arizona.edu), AE(Lunar and Planetary Laboratory, Lunar and Planetary Laboratory, Tucson, AZ 85721, United States ; wboynton@lpl.arizona.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2007, abstract #P11A-0260 |
| Publication Date: | Dec 2007 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5210, 5405, 5704), 5405 Atmospheres (0343, 1060), 5422 Ices, 5462 Polar regions, 6225 Mars |
| Abstract Copyright: | (c) 2007: American Geophysical Union |
| Bibliographic Code: | 2007AGUFM.P11A0260G |
| Abstract: | We model the variation of non-condensable trace gases that results from the seasonal cycle of CO2 on Mars. A simple condensation scheme has been incorporated into MarsWRF, a 3-dimensional numerical model for the atmospheres of Mars. Non-condensable trace gas (mostly N2 and Ar) mass mixing ratios are affected by the phase change of CO2 and by transport. The distribution of Ar abundance has been observed by the Gamma Ray Spectrometer on the Mars 2001 Odyssey spacecraft. We are able to qualitatively reproduce the Ar observations, including the seasonal evolving latitudinal distribution. However, the modeled magnitudes of maximum enrichment are lower than observed. Smoothing Ar enrichment in the vertical reduces susceptibility to transport by near-surface, off-cap circulation, therefore gives further enhancement of non-condensable tracer in the winter pole. We suggest that a missing process in the model may account for the underestimation. An extra buoyancy term in the dynamics should result from the vertical gradient in mean molecular mass as Ar mass mixing ratio increases. |
| Title: | Ensemble-Based Data Assimilation With a Martian GCM |
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| Authors: | Lawson, W.; Richardson, M. I.; McCleese, D. J.; Anderson, J. L.; Chen, Y.; Snyder, C. |
| Affiliation: | AA(Caltech, 1200 E. California Blvd., Pasadena, CA 91125, United States ; wglawson@gps.caltech.edu), AB(Caltech, 1200 E. California Blvd., Pasadena, CA 91125, United States ; mir@gps.caltech.edu), AC(JPL, 4800 Oak Grove Dr., Pasadena, CA 91109, United States ; daniel.j.mccleese@jpl.nasa.gov), AD(NCAR, P.O. Box 3000, Boulder, CO 80307-3000, United States ; jla@ucar.edu), AE(NCAR, P.O. Box 3000, Boulder, CO 80307-3000, United States ; yochen@ucar.edu), AF(NCAR, P.O. Box 3000, Boulder, CO 80307-3000, United States ; chriss@ucar.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2007, abstract #P11A-0251 |
| Publication Date: | Dec 2007 |
| Origin: | AGU |
| Keywords: | 3315 Data assimilation, 3346 Planetary meteorology (5445, 5739), 5704 Atmospheres (0343, 1060), 6225 Mars |
| Abstract Copyright: | (c) 2007: American Geophysical Union |
| Bibliographic Code: | 2007AGUFM.P11A0251L |
| Abstract: | Quantitative study of Mars weather and climate will ultimately stem from analysis of its dynamic and thermodynamic fields. Of all the observations of Mars available to date, such fields are most easily derived from mapping data (radiances) of the martian atmosphere as measured by orbiting infrared spectrometers and radiometers (e.g., MGS / TES and MRO / MCS). Such data-derived products are the solutions to inverse problems, and while individual profile retrievals have been the popular data-derived products in the planetary sciences, the terrestrial meteorological community has gained much ground over the last decade by employing techniques of data assimilation (DA) to analyze radiances. Ancillary information is required to close an inverse problem (i.e., to disambiguate the family of possibilities that are consistent with the observations), and DA practitioners inevitably rely on numerical models for this information (e.g., general circulation models (GCMs)). Data assimilation elicits maximal information content from available observations, and, by way of the physics encoded in the numerical model, spreads this information spatially, temporally, and across variables, thus allowing global extrapolation of limited and non-simultaneous observations. If the model is skillful, then a given, specific model integration can be corrected by the information spreading abilities of DA, and the resulting time sequence of "analysis" states are brought into agreement with the observations. These analysis states are complete, gridded estimates of all the fields one might wish to diagnose for scientific study of the martian atmosphere. Though a numerical model has been used to obtain these estimates, their fidelity rests in their simultaneous consistency with both the observations (to within their stated uncertainties) and the physics contained in the model. In this fashion, radiance observations can, say, be used to deduce the wind field. A new class of DA approaches based on Monte Carlo approximations, "ensemble-based methods," has matured enough to be both appropriate for use in planetary problems and exploitably within the reach of planetary scientists. Capitalizing on this new class of methods, the National Center for Atmospheric Research (NCAR) has developed a framework for ensemble-based DA that is flexible and modular in its use of various forecast models and data sets. The framework is called DART, the Data Assimilation Research Testbed, and it is freely available on-line. We have begun to take advantage of this rich software infrastructure, and are on our way toward performing state of the art DA in the martian atmosphere using Caltech's martian general circulation model, PlanetWRF. We have begun by testing and validating the model within DART under idealized scenarios, and we hope to address actual, available infrared remote sensing datasets from Mars orbiters in the coming year. We shall present the details of this approach and our progress to date. |
| Title: | Seasonal Variations of Methane Cloud Formation in a Global Model of Titan's Atmosphere, TitanWRF. |
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| Authors: | Newman, Claire E.; Richardson, M. I.; Xiao, J.; Inada, A. |
| Affiliation: | AA(Caltech), AB(Caltech), AC(Caltech), AD(Caltech) |
| Journal: | American Astronomical Society, DPS meeting #39, #56.06 |
| Publication Date: | Oct 2007 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2007: American Astronomical Society |
| Bibliographic Code: | 2007DPS....39.5606N |
| Abstract: | We will present results from multi-annual simulations of methane condensation in the troposphere of Titan, using the global version of the TitanWRF atmospheric model. TitanWRF is the Titan version of the PlanetWRF model (Richardson et al., 2007, JGR, in press). PlanetWRF differs from the model upon which it is based, NCAR's Weather Research and Forecasting model (www.wrf-model.org), in that it (a) can be run in global as well as limited area mode, and (b) is structured to be easily adapted to planets other than the Earth. The methane condensation scheme includes for example (i) a surface source, depending on the sub-saturation of the lowest atmospheric layer and the strength of near-surface winds, as in Tokano et al. (2001, Icarus, 153, 130-147); (ii) determination of the type of condensate produced (methane ice or a binary liquid including dissolved nitrogen) depending on temperature; (iii) inclusion of a decrease in saturation vapor pressure for the binary liquid; (iv) different assumptions about the fate of any condensate produced. Preliminary results show some interesting similarities to the observed location and timing of Titan clouds, and suggest further investigations which will also be discussed. This work was funded by the Outer Planets Research Program and by the Applied Information Systems Research Program. |
| Title: | Modeling and Implications of Exotic Martian Radio Emission |
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| Authors: | Heavens, Nicholas; McEwan, I. J.; Busch, M. W.; Newman, C. E.; Richardson, M. I. |
| Affiliation: | AA(California Institute of Technology), AB(California Institute of Technology), AC(California Institute of Technology), AD(California Institute of Technology), AE(California Institute of Technology) |
| Journal: | American Astronomical Society, DPS meeting #39, #17.05 |
| Publication Date: | Oct 2007 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2007: American Astronomical Society |
| Bibliographic Code: | 2007DPS....39.1705H |
| Abstract: | Since the work of Eden and Vonnegut (1973, Science, 180, 962-963), it has been hypothesized that the lower atmosphere of Mars might be highly electrically active during dusty conditions. This electrical activity supposedly results from the charging of dust and sand particles by collisions with other dust and sand particles of contrasting size and/or composition and the discharge of these particles into an atmosphere with a low breakdown potential. Farrell et al. (1999, JGR, 104, 3795-3801) and Renno et al. (2003, GRL, 30, 2140) have proposed that these electrical discharges might be a source of intense non-thermal radiation and therefore detectable. In this work, we synthesize the work of Farrell et al. (1999) and Renno et al. (2003) into a model of non-thermal radiation (primarily UHF) produced by emission from arc discharges between sand and dust particles. Although this model is highly unconstrained, it can provide insight into the source characteristics of such radiation. We use this model to analyze the observations of Busch et al. (this meeting) and consider the implications of our analysis for surface spacecraft operations, enhancement of dust lifting by strong electric fields (Kok and Renno, 2006, GRL, 33, L19S10), meteorological monitoring, and lower atmosphere chemical synthesis on Mars (Atreya et al., 2006, Astrobiology, 6, 439). |
| Title: | Mars' L-Band Radio Emission |
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| Authors: | Busch, Michael W.; Heavens, N. G.; Butler, B. J.; Kulkarni, S. R.; McEwan, I. J.; Richardson, M. I. |
| Affiliation: | AA(Caltech), AB(Caltech), AC(NRAO), AD(Caltech), AE(Caltech), AF(Caltech) |
| Journal: | American Astronomical Society, DPS meeting #39, #17.04 |
| Publication Date: | Oct 2007 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2007: American Astronomical Society |
| Bibliographic Code: | 2007DPS....39.1704B |
| Abstract: | Several authors have suggested that martian dust storms should produce radio emission from electrostatic discharges between dust grains (e.g. Farrell et al. 1999, JGR 104, 3795-3801; Renno et al. 2003, GRL 30, 2140). We report results from ongoing VLA observations of Mars at L-band (20 cm). With the VLA in A-configuration (35 km maximum baseline), we resolve Mars and can compare the pattern of radio emission to the expected thermal flux and the positions of known dust storms. |
| Title: | Non-Condensable Gas in a Mars General Circulation Model |
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| Authors: | Guo, X.; Richardson, M. I.; Newman, C. E. |
| Journal: | Seventh International Conference on Mars, held July 9-13, 2007 in Pasadena, California, LPI Contribution No. 1353, p.3375 |
| Publication Date: | Jul 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPICo1353.3375G |
| Abstract: | We use a simple CO2 condensation scheme in the PlanetWRF to study the tracer dynamics in the Mars atmosphere. Non-condensable gas changes as a result of CO2 condensation. It provides us a way to study the tracer gas transportation and improve the GCM parameterization. |
| Title: | Atmospheric Dynamics of Early Mars |
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| Authors: | Soto, A.; Mischna, M. A.; Richardson, M. I. |
| Journal: | Seventh International Conference on Mars, held July 9-13, 2007 in Pasadena, California, LPI Contribution No. 1353, p.3327 |
| Publication Date: | Jul 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPICo1353.3327S |
| Abstract: | Newly developed global and mesoscale atmospheric models allow us to investigate not just radiative models of early Mars, as previously done, but also the atmospheric dynamics of early Mars. We use one such model, Caltech's MarsWRF, to investigate the atmospheric dynamics of early Mars. |
| Title: | MarsWRF: A General Purpose, Local to Global Numerical Model for the Martian Climate and Atmosphere |
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| Authors: | Toigo, A.; Richardson, M. I.; Newman, C. E. |
| Journal: | Seventh International Conference on Mars, held July 9-13, 2007 in Pasadena, California, LPI Contribution No. 1353, p.3324 |
| Publication Date: | Jul 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPICo1353.3324T |
| Abstract: | A new atmospheric model has been developed with generalized map-projection, multi-scale, and nesting capabilities, blurring the distinction between global and mesoscale models, and enabling investigation of coupling between processes on all scales. |
| Title: | Adapting State of the Art Data Assimilation Approaches for Use with the Mars Climate Sounder and the PlanetWRF Martian GCM |
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| Authors: | Lawson, W. G.; Richardson, M. I.; McCleese, D. J.; Schofield, J. T.; Aharonson, O.; Calcutt, S. B.; Irwin, P. G. J.; Kass, D. M.; Leovy, C. B.; Lewis, S. R.; Paige, D. A.; Read, P. L.; Taylor, F. W.; Zurek, R. W. |
| Journal: | Seventh International Conference on Mars, held July 9-13, 2007 in Pasadena, California, LPI Contribution No. 1353, p.3321 |
| Publication Date: | Jul 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPICo1353.3321L |
| Abstract: | We shall present our progress to date of our efforts to adapt state of the art data assimilation approaches within the terrestrial meteorological community for use with the new MCS dataset and a martian GCM. |
| Title: | High Vertical and Temporal Resolution Observations of the Martian Atmosphere |
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| Authors: | McCleese, D. J.; Schofield, J. T.; Adou, W.; Aharonson, O.; Calcutt, S. B.; Irwin, P.; Kass, D. M.; Kleinboeh, A.; Leovy, C. B.; Lewis, S.; Paige, D. A.; Read, P. L.; Richardson, M. I.; Taylor, F. W.; Zurek, R. W. |
| Journal: | Seventh International Conference on Mars, held July 9-13, 2007 in Pasadena, California, LPI Contribution No. 1353, p.3252 |
| Publication Date: | Jul 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPICo1353.3252M |
| Abstract: | Observations of the martian atmosphere made by the Mars Climate Sounder (MCS) onboard MRO reveal atmospheric structure not previously reported. This abstract reports findings related to atmospheric thermal structure and the distributions of dust and condensates. |
| Title: | Two Aerodynamic Roughness Maps Derived from MOLA Data and Their Effects on Boundary Layer Properties in a Mars GCM |
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| Authors: | Heavens, N. G.; Richardson, M. I.; Toigo, A. D. |
| Journal: | Seventh International Conference on Mars, held July 9-13, 2007 in Pasadena, California, LPI Contribution No. 1353, p.3218 |
| Publication Date: | Jul 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPICo1353.3218H |
| Abstract: | We develop two aerodynamic roughness maps of Mars based on different assumptions and using different types of MOLA data. We investigate the differences between boundary layer processes in a Mars GCM forced by each map, also considering implications for dust devil activity. |
| Title: | Using Mars Orbital Camera Dust Devil Observations to Develop Schemes for Representing Dust Devils in Mars General Circulation Models |
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| Authors: | Heavens, N. G.; Richardson, M. I.; Newman, C. E. |
| Journal: | Seventh International Conference on Mars, held July 9-13, 2007 in Pasadena, California, LPI Contribution No. 1353, p.3208 |
| Publication Date: | Jul 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPICo1353.3208H |
| Abstract: | Current methods of representing dust devil activity in Mars GCMs are reviewed. An alternate method is proposed. This method is then used in conjunction with Mars GCM simulations and MOC WA dust devil observations to develop new schemes for representing dust devil activity. |
| Title: | Observations of the South Polar Atmosphere and Condensates: Early Results from the Mars Climate Sounder |
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| Authors: | McCleese, D. J.; Schofield, J. T.; Aharonson, O.; Calcutt, S. B.; Irwin, P.; Ivanov, A. B.; Kass, D. M.; Leovy, C. B.; Lewis, S.; Paige, D. A.; Read, P. L.; Richardson, M. I.; Taylor, F. W.; Zurek, R. W. |
| Journal: | 38th Lunar and Planetary Science Conference, (Lunar and Planetary Science XXXVIII), held March 12-16, 2007 in League City, Texas. LPI Contribution No. 1338, p.1413 |
| Publication Date: | Mar 2007 |
| Origin: | LPI |
| Bibliographic Code: | 2007LPI....38.1413M |
| Abstract: | MCS observes the martian atmosphere and surface. This paper focuses on studies of the thermal structure, clouds, and hazes in the winter south polar regions, as well as high altitude clouds at mid-latitudes. |
2006
| Title: | VenusWRF: A New Venus GCM Using PlanetWRF |
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| Authors: | Lee, C.; Richardson, M. I.; Newman, C. E.; Toigo, A. D. |
| Affiliation: | AA(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Blvd M/C 150-21, Pasadena, CA 91125 United States ; lee@gps.caltech.edu), AB(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Blvd M/C 150-21, Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AC(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Blvd M/C 150-21, Pasadena, CA 91125 United States ; claire@gps.caltech.edu), AD(Kobe University, Graduate School of Science and Technology Kobe University Rokkodai-cho 1-1, Nada-ku, Kobe, 657-8501 Japan ; toigo@kobe-u.ac.jp) |
| Journal: | American Geophysical Union, Fall Meeting 2006, abstract #P51B-1202 |
| Publication Date: | Dec 2006 |
| Origin: | AGU |
| Keywords: | 3319 General circulation (1223), 3334 Middle atmosphere dynamics (0341, 0342), 3389 Tides and planetary waves, 6295 Venus |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| Bibliographic Code: | 2006AGUFM.P51B1202L |
| Abstract: | The NCAR terrestrial Weather Research and Forecast (WRF) atmospheric model has been converted into a global, planetary GCM, with fully compressible treatment of the atmosphere, 3D Coriolis and curvature treatment, and hydrostatic and non-hydrostatic options. The model has been converted for use on Venus, initially using the linearized forcing and dissipation parameterizations of recent Venus GCMs (Lee et al.(2005), Yamamoto and Takahashi (2003)). Analysis of the momentum transports, atmospheric circulation, and super-rotation diagnostics will be presented. Preliminary analysis of experiments using more realistic forcing on longer timescales will also be presented, and the response of the atmospheric circulation to a diurnally varying forcing will be described. |
| Title: | Mars Climate Sounder on the Mars Reconnaissance Orbiter |
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| Authors: | McCleese, D. J.; Schofield, J. T.; Taylor, F. W.; Aharonson, O.; Calcutt, S. B.; Irwin, P.; Kass, D. M.; Leovy, C. B.; Lewis, S.; Paige, D. A.; Read, P. L.; Richardson, M. I.; Zurek, R. W. |
| Affiliation: | AA(Jet Propulsion Laboratory, M/S 180/600 4800 Oak Grove Dr., Pasadena, CA 91109 United States ; Daniel.J.Mccleese@jpl.nasa.gov), AB(Jet Propulsion Laboratory, M/S 180/600 4800 Oak Grove Dr., Pasadena, CA 91109 United States ; John.T.Schofield@jpl.nasa.gov), AC(Department of Atmospheric, Oceanic & Planetary Sciences University of Oxford, Wellington Square, Oxford, UK OX1 3PU United Kingdom ; ftw@atm.ox.ac.uk), AD(Division of Geology and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States ; oa@gps.caltech.edu), AE(Department of Atmospheric, Oceanic & Planetary Sciences University of Oxford, Wellington Square, Oxford, UK OX1 3PU United Kingdom ; calcutt@atm.ox.ac.uk), AF(Department of Atmospheric, Oceanic & Planetary Sciences University of Oxford, Wellington Square, Oxford, UK OX1 3PU United Kingdom ; patrick.Irwin@atm.ox.ac.uk), AG(Jet Propulsion Laboratory, M/S 180/600 4800 Oak Grove Dr.,! Pasadena, CA 91109 United States ; David.M.Kass@jpl.nasa.gov), AH(Department of Atmospheric Science, University of Washington, P.O. 341640, Seattle, WA 98195 United States ; conway@atomos.washington.edu), AI(Department of Physics and Astronomy, Open University, P.O. 197, Milton Keynes, UK MK7 6AA United Kingdom ; s.r.lewis@open.ac.uk), AJ(Department of Earth and Space Sciences, University of California, 595 Charles Youg Drive East P.O. 951567, Los Angeles, CA 90095 United States ; dap@mars.ucla.edu), AK(Department of Atmospheric, Oceanic & Planetary Sciences University of Oxford, Wellington Square, Oxford, UK OX1 3PU United Kingdom ; p.read1@physics.ox.ac.uk), AL(Division of Geology and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AM(Jet Propulsion Laboratory, M/S 180/600 4800 Oak Grove Dr., Pasadena, CA 91109 United States ; Richard.W.Zurek@jpl.nasa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2006, abstract #P33A-05 |
| Publication Date: | Dec 2006 |
| Origin: | AGU |
| Keywords: | 6000 PLANETARY SCIENCES: COMETS AND SMALL BODIES, 6005 Atmospheres (1060), 6015 Dust, 6225 Mars |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| Bibliographic Code: | 2006AGUFM.P33A..05M |
| Abstract: | The Mars Climate Sounder (MCS) is currently making detailed measurements of the vertical profiles of atmospheric temperature, water vapor, dust and condensates and the radiative balance of the polar caps from the polar, near-circular orbit of the Mars Reconnaissance Orbiter. MCS radiometer operating in eight spectral channels in the mid and far infrared with a broadband 0.3 to 3 micron channel for measurements of solar radiation reflected from the Martian surface. In this paper, we describe the measurement approach and the weather and climate objectives of MCS. The instrument observes the limb of the atmosphere from 0 to 80 km altitude with 5 km vertical resolution, and the surface at nadir and off-nadir angles, including excellent coverage of the bi-directional reflection functions of polar caps. Initial observations of the Martian atmosphere and surface collected during the first few months of MCS operation will be presented. |
| Title: | Data Assimilation With the Mars Climate Sounder |
|---|---|
| Authors: | Lawson, W.; Richardson, M. I.; McCleese, D. J.; Schofield, J.; Aharonson, O.; Calcutt, S.; Irwin, P.; Kass, D. M.; Leovy, C.; Lewis, S. R.; Paige, D. A.; Read, P. L.; Taylor, F. W.; Zurek, R. W. |
| Affiliation: | AA(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Blvd., Pasadena, CA 91125 United States ; wglawson@gps.caltech.edu), AB(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AC(Jet Propulsion Laboratory, Science Division 4800 Oak Grove Drive, Pasadena, CA 91109 United States ; daniel.j.mccleese@jpl.nasa.gov), AD(Jet Propulsion Laboratory, Science Division 4800 Oak Grove Drive, Pasadena, CA 91109 United States ; john.t.schofield@jpl.nasa.gov), AE(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Blvd., Pasadena, CA 91125 United States ; oa@gps.caltech.edu), AF(Oxford University, Atmospheric, Oceanic and Planetary Physics Parks Road, Oxford, OX1 3PU United Kingdom ; calcutt@atm.ox.ac.uk), AG(Oxford University, Atmospheric, Oceanic and Planetary Physi! cs Parks Road, Oxford, OX1 3PU United Kingdom ; irwin@atm.ox.ac.uk), AH(Jet Propulsion Laboratory, Science Division 4800 Oak Grove Drive, Pasadena, CA 91109 United States ; David.M.Kass@jpl.nasa.gov), AI(University of Washington, Department of Atmospheric Sciences ATG Building, Seattle, WA 98195 United States ; conway@atmos.washington.edu), AJ(The Open University, Department of Physics and Astronomy Walton Hall, Milton Keynes, MK7 6AA United Kingdom ; S.R.Lewis@open.ac.uk), AK(University California, Los Angeles, Department of Earth and Space Sciences 595 Charles Young Drive East, Los Angeles, CA 90095 United States ; dap@mars.ucla.edu), AL(Oxford University, Atmospheric, Oceanic and Planetary Physics Parks Road, Oxford, OX1 3PU United Kingdom ; p.read1@physics.ox.ac.uk), AM(Oxford University, Atmospheric, Oceanic and Planetary Physics Parks Road, Oxford, OX1 3PU United Kingdom ; f.taylor1@physics.ox.ac.uk), AN(Jet Propulsion Laboratory, Science Division 4800 Oak Grove Drive! , Pasadena, CA 91109 United States ; Richard.W.Zurek@jpl.nasa.! gov) |
| Journal: | American Geophysical Union, Fall Meeting 2006, abstract #P23B-0061 |
| Publication Date: | Dec 2006 |
| Origin: | AGU |
| Keywords: | 3315 Data assimilation, 3346 Planetary meteorology (5445, 5739), 5445 Meteorology (3346) |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| Bibliographic Code: | 2006AGUFM.P23B0061L |
| Abstract: | Data assimilation is a suite of techniques that has proven useful to studies in terrestrial atmospheric science. Data assimilation elicits the information content in observations in order to improve one's estimate of the atmospheric state, typically the state of a numerical model. The improved estimate is the ideal data product to be queried and diagnosed for scientific study of dynamics, circulation, and transport. Martian atmospheric modeling efforts have been improving, and several models can now reasonably reproduce the climate implied by historical observations (e.g., MGS / TES). The global planetary version of WRF (NCAR's mesoscale Weather Research and Forecasting model) is one such model that can reasonably simulate the martian atmosphere and its variability. Previous data assimilation efforts for the martian atmosphere have used techniques that assume stationary error statistics. Our intent is to combine the information content in observations from the Mars Climate Sounder (MCS) with the global planetary version of WRF configured for Mars using a modern data assimilation technique, proven in terrestrial applications, which approximates the evolution of atmospheric error statistics. Terrestrial research experience has shown that ensemble-based data assimilation approaches (e.g., the ensemble Kalman filter) are effective when observations are relatively sparse because their flow-dependent error estimates can maximally spread observational information content. Having a data stream from a single orbiting atmospheric sounder should provide a good test bed for such approaches in a martian context. We present our initial tests and thoughts for how ensemble-based data assimilation can provide improved martian atmospheric state estimates using MCS data. We also discuss unique challenges for performing data assimilation in the martian atmosphere. We initially focus on assimilating retrieved profiles, but we intend to address directly assimilating radiances. |
| Title: | Modeling the Martian Dust Cycle with MarsWRF |
|---|---|
| Authors: | Newman, C. E.; Richardson, M. I.; Toigo, A. D. |
| Affiliation: | AA(California Institute of Technology, MC 150-21, GPS, Caltech, 1200 E. California Blvd., Pasadena, CA 91125 United States ; claire@gps.caltech.edu), AB(California Institute of Technology, MC 150-21, GPS, Caltech, 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AC(Kobe University, Graduate School of Science and Technology, Kobe University, Rokkodai-cho 1-1, Nada-ku, Japan, Kobe, 657-8501 Japan ; toigo@astro.cornell.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2006, abstract #P23A-0048 |
| Publication Date: | Dec 2006 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5210, 5405, 5704), 5405 Atmospheres (0343, 1060), 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| Bibliographic Code: | 2006AGUFM.P23A0048N |
| Abstract: | MarsWRF is a new general circulation model of the Martian atmosphere. A modified, planetary version of the terrestrial, mesoscale Weather Research and Forecasting (WRF) model, MarsWRF can operate as either a limited area or global model, and can be run with higher resolution regions embedded within the outer domain. We will present first results from using the basic global version of MarsWRF to simulate the Martian dust cycle, with two dust lifting processes (near-surface wind stress and dust devils) and with dust as both a passive and an active tracer. In the latter case, we will examine the feedbacks between injected dust and the atmospheric state, and will discuss the realism of the simulations and our future plans for improvement. We will also outline future plans to run MarsWRF with embedded high resolution domains in key lifting areas, and discuss how this will enable us to study multi-scale feedbacks. |
| Title: | Simulation of Martian Cloud Formation Associated With Topography by the Planetary Weather Research and Forecasting Model |
|---|---|
| Authors: | Inada, A.; Newman, C. E.; Richardson, M. I.; Mischna, M. A.; Toigo, A. D. |
| Affiliation: | AA(California Institute of Technology, M. S. 150-21 1200 E. California Blvd., Pasadena, CA 91104 United States ; inada@gps.caltech.edu), AB(California Institute of Technology, M. S. 150-21 1200 E. California Blvd., Pasadena, CA 91104 United States ; claire@gps.caltech.edu), AC(California Institute of Technology, M. S. 150-21 1200 E. California Blvd., Pasadena, CA 91104 United States ; mir@gps.caltech.edu), AD(Jet Propulsion Laboratory, M.S. 183-401 4800 Oak Grove Drive, Pasadena, CA 91109 United States ; michael.a.mischna@jpl.nasa.gov), AE(Graduate School of Science and Technology, Kobe Univ., 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan ; toigo@astro.cornell.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2006, abstract #P23A-0045 |
| Publication Date: | Dec 2006 |
| Origin: | AGU |
| Keywords: | 0305 Aerosols and particles (0345, 4801, 4906), 0320 Cloud physics and chemistry, 6225 Mars |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| Bibliographic Code: | 2006AGUFM.P23A0045I |
| Abstract: | Martian clouds are often seen over volcanoes, Valles Marineris and troughs in Polar Regions. A basic mechanism of cloud formation is that an air parcel with water vapor is lifted in the vertical wind, becomes saturated due to colder surrounding air, and the vapor transforms to water ice. We will show simulation results of cloud formation with the Planetary Weather Research and Forecasting (planetWRF) model. It has been modified at Caltech from the terrestrial mesoscale WRF model developed mainly by the National Center for Atmospheric Research (NCAR). It can simulate, for example, the diurnal / seasonal change of wind direction and temperature profile in a limited area with high spatial resolution. Currently we have two microphysics schemes. The first includes heterogeneous nucleation, growth and sublimation of water ice particles, and sedimentation due to gravity. Particles are allowed to precipitate to the surface and form frost. The second is a much faster, simpler parameterization in which the parameter choices are based on the results of the first method. Using the latter scheme decreases the computational time greatly. |
| Title: | Martian Mesospheric Clouds: Latest Results from THEMIS-VIS |
|---|---|
| Authors: | McConnochie, T. H.; Bell, J. F.; Savransky, D.; Wolff, M. J.; Richardson, M. I.; Toigo, A. D.; Wang, H.; Christensen, P. R. |
| Affiliation: | AA(Cornell University, Space Sciences Building, Cornell University, Ithaca, NY 14853 United States ; thm9@cornell.edu), AB(Cornell University, Space Sciences Building, Cornell University, Ithaca, NY 14853 United States ; jfb8@cornell.edu), AC(Cornell University, Space Sciences Building, Cornell University, Ithaca, NY 14853 United States ; ds264@cornell.edu), AD(Space Science Institute, 18970 Cavendish Road, Brookfield, WI 53045 United States ; wolff@spacescience.org), AE(California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AF(Kobe University, Graduate School of Science and Technology Rokkodai-cho 1-1, Nada- ku, Kobe, 657-8501 Japan ; toigo@astro.cornell.edu), AG( Harvard-Smithsonian Center for Astrophysics, MS-50, 60 GARDEN STREET, Cambridge, MA 02138 United States ; hwang@cfa.harvard.edu), AH(Arizona State University, Dept. of Geological Sciences, Tempe, AZ 85287-6305 United States ; phil.christe! nsen@asu.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2006, abstract #P23A-0044 |
| Publication Date: | Dec 2006 |
| Origin: | AGU |
| Keywords: | 5405 Atmospheres (0343, 1060), 5464 Remote sensing |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| Bibliographic Code: | 2006AGUFM.P23A0044M |
| Abstract: | We present an update of THEMIS-VIS observations of clouds in the Martian mesosphere. These observations were previously discussed by McConnochie et al. [2005, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract P21E-03]. In addition to the ongoing THEMIS-VIS studies, recent observations of mesospheric clouds by Mars Global Surveyor [Clancy et al. 2004, Bull. Amer. Astron. Soc., 36 pg. 1128], and by SPICAM on Mars Express [Montmessin et al., 2006, Icarus 183, 403-410], are contributing to a rapid evolution in our understanding of these high-altitude aerosols. THEMIS-VIS measures cloud altitude using the parallax drift of high-altitude features, and the velocity by exploiting the time delay in the THEMIS-VIS imaging sequence. Additionally, the high resolution nadir-pointed THEMIS-VIS observations show cloud morphologies at scales on the order of 30 meters per pixel. The new results that we present include the distribution of the mesospheric clouds in location, season, altitude and velocity; comparison of the cloud velocities with GCM wind estimates; morphological classification of the clouds; and inferences about the mass, particle size, and composition of the aerosols derived from radiative transfer modeling. |
| Title: | CO2 condensation in the Martian environment |
|---|---|
| Authors: | Guo, X.; Newman, C. E.; Richardson, M. I.; Wood, S. E. |
| Affiliation: | AA(Division of Geological and Planetary Science, California Institute of Technology, MC 150- 21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; xin@gps.caltech.edu), AB(Division of Geological and Planetary Science, California Institute of Technology, MC 150- 21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; claire@gps.caltech.edu), AC(Division of Geological and Planetary Science, California Institute of Technology, MC 150- 21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AD(Department of Atmospheric Sciences,University of Washington, 408 ATG Building, Box 351640, University of Washington, Seattle, WA 98195-1640 United States ; sewood@atmos.washington.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2006, abstract #P23A-0041 |
| Publication Date: | Dec 2006 |
| Origin: | AGU |
| Keywords: | 0305 Aerosols and particles (0345, 4801, 4906), 0320 Cloud physics and chemistry, 0343 Planetary atmospheres (5210, 5405, 5704), 5405 Atmospheres (0343, 1060) |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| Bibliographic Code: | 2006AGUFM.P23A0041G |
| Abstract: | It has been suggested that cirrus clouds formed of CO2 gas may have significantly affected the early history of the climate of Mars. Evidence of the existence of CO2 ice clouds in the current atmosphere of Mars has also been reported. We implement a CO2 microphysics scheme to the PlanetWRF Model and focus on its applications in the Martian environment. This physical scheme includes heterogenous nucleation, homogenous nucleation, ion nucleation and CO2 ice particle growth. CO2 ice physics is coupled with the dust cycle, CO2 cycle and possibly water cycle. With followed radiative transfer study and comparison with spacecraft data products, we hope to have better insight into the history of the climate of Mars and its current circulating cycles. Complete understanding of the role that CO2 ice clouds play in the Martian climate system requires both modeling and laboratory work of CO2 ice formation processes, which have become two of the most urgent tasks in the Mars science community. |
| Title: | Mesoscale Simulation at Valles Marineris with the Planetary Weather Research and Forecasting Model |
|---|---|
| Authors: | Inada, Ai; Newman, C. E.; Richardson, M. I.; Mischna, M. A.; Toigo, A. D. |
| Affiliation: | AA(California Institute of Technology), AB(California Institute of Technology), AC(California Institute of Technology), AD(Jet Propulsion Laboratory), AE(Graduate School of Science and Technology, Kobe Univ., Japan) |
| Journal: | American Astronomical Society, DPS meeting #38, #70.05; Bulletin of the American Astronomical Society, Vol. 38, p.625 |
| Publication Date: | Sep 2006 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2006: American Astronomical Society |
| Bibliographic Code: | 2006DPS....38.7005I |
| Abstract: | Valles Marineris is the deepest canyon on Mars, and its topography affects the climate both globally and locally. The equatorial cloud belt appears from areocentric solar longitudes of 45 to 150 degrees, and the clouds associated with the valley are a part of it. Before the main belt developed in 2004, the High Resolution Stereo Camera (HRSC) and the spectrometer OMEGA on board Mars Express observed a dusty haze floating inside the valley. It became thinner after three days, and disappeared within ten days. The Planetary Weather Research and Forecasting (WRF) model has been modified at Caltech from the terrestrial mesoscale WRF model developed mainly by the National Center for Atmospheric Research (NCAR). It can simulate the diurnal / seasonal change of wind direction and temperature profile in a limited area with high spatial resolution. Formations of clouds and dust hazes strongly depend on these phenomena. We will present the results of mesoscale simulations of Valles Marineris in Northern spring to summer. |
| Title: | PlanetWRF - A Flexible, Multi-scale Model For Planetary Atmospheres |
|---|---|
| Authors: | Richardson, Mark I.; Newman, C. E.; Toigo, A. D. |
| Affiliation: | AA(Caltech), AB(Caltech), AC(Kobe University, Japan) |
| Journal: | American Astronomical Society, DPS meeting #38, #70.04; Bulletin of the American Astronomical Society, Vol. 38, p.625 |
| Publication Date: | Sep 2006 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2006: American Astronomical Society |
| Bibliographic Code: | 2006DPS....38.7004R |
| Abstract: | PlanetWRF is a global, planetary version of the mesoscale, Earth-based WRF (Weather Research and Forecasting) model (www.wrf-model.org). With minimal changes, and using the same basic dynamical core and parameterizations of physical processes, it may be run as a global, mesoscale, LES (large eddy simulation), latitude-height or one-dimensional model. This makes it exceptionally flexible and applicable to a range of studies, including for example its use as a radiative-convective model to test a new radiative transfer scheme, or as a three-dimensional global model to examine wave-mean flow interactions. It is also easily configured for any planetary atmosphere, and has so far been applied to the atmospheres of Earth, Mars, Titan and most recently Venus. We will present an overview of results to date, including tests of the dynamical core using simplified forcing, Mars simulations that compare very well with observations, and Mars simulations using a `rotated’ grid in which the poles are dealt with particularly well. We will also outline future work using high resolution `nests’ placed within the global domain to enable multi-scale feedbacks. This work is partially funded by NASA's AISR and OPR research programs, and we would also like to acknowledge our use of Caltech's new 1024 node Geological and Planetary Sciences Dell cluster, CITerra. |
| Title: | Forecasting Martian Dust Devils |
|---|---|
| Authors: | Heavens, Nicholas G.; Richardson, M. I.; Newman, C. E. |
| Affiliation: | AA(California Institute of Technology), AB(California Institute of Technology), AC(California Institute of Technology) |
| Journal: | American Astronomical Society, DPS meeting #38, #60.04; Bulletin of the American Astronomical Society, Vol. 38, p.598 |
| Publication Date: | Sep 2006 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2006: American Astronomical Society |
| Bibliographic Code: | 2006DPS....38.6004H |
| Abstract: | In recent years, there have been at least two broad surveys of dust devil activity over various regions of Mars (Balme et al., 2003) (Fisher et al., 2005). The results of these surveys provide useful constraints for designing and testing new schemes for forecasting Martian dust devils, in particular their number density and size at a given place and time. This endeavor would be useful both for future spacecraft operations and improved dust cycle simulation within Martian general circulation models. At present, the predominant scheme for dust devil forecasting is based on Renno et al. (1998), which as presently applied only gives a relative measure of the maximum incidence of dust devils in a given area based on thermodynamic considerations and predictions of their wind velocities etc. In this study, the Mars implementation of the Planetary Weather Research and Forecasting Model (planetWRF) and the results of the surveys are used to demonstrate that dust devil formation is likely more mechanically than thermodynamically controlled. As an alternative, we propose the existence of one or multiple "nucleation criteria” for dust devil formation that can be combined with the well-known size-duration relation for terrestrial dust devils (Sinclair, 1966) in order to forecast number density. We use planetWRF output and survey data to evaluate various nucleation criteria based on: (1) inhibition of convection by near-surface mechanical turbulence (Deardorff, 1972); (2) inhibition or enhancement of convection by mesoscale to synoptic scale wind systems; and (3) the possibility of the dust devil's rotation inhibiting its own convective support within the near-surface superadiabatic layer. This work is supported in part by NASA. The numerical simulations for this research were performed on Caltech's CITerra cluster. |
| Title: | TitanWRF - A Computationally Efficient Three-dimensional Model of Titan's Atmosphere |
|---|---|
| Authors: | Newman, Claire; Richardson, M. I.; Inada, A.; Xiao, J. |
| Affiliation: | AA(California Institute of Technology), AB(California Institute of Technology), AC(California Institute of Technology), AD(California Institute of Technology) |
| Journal: | American Astronomical Society, DPS meeting #38, #27.21; Bulletin of the American Astronomical Society, Vol. 38, p.531 |
| Publication Date: | Sep 2006 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2006: American Astronomical Society |
| Bibliographic Code: | 2006DPS....38.2721N |
| Abstract: | TitanWRF is the Titan version of the PlanetWRF model, which is a global, planetary version of the mesoscale, Earth-based WRF (Weather Research and Forecasting) model (www.wrf-model.org). It uses a full radiative transfer scheme (a more recent version of that described in McKay, Pollack and Courtin, "The Thermal Structure of Titan's Atmosphere", Icarus 1989) including diurnal and seasonal variations in solar forcing, and is fully three-dimensional allowing waves and their effect on the mean flow to be represented explicitly. This required us to use a computationally efficient model - Titan's thick sluggish atmosphere has very long dynamical time-scales, and a Titan year is 30 Earth years, meaning that long simulations are needed to `spin up’ the model atmosphere. PlanetWRF was therefore an excellent choice, as its basis (the WRF model) was designed to run efficiently on parallel machines, such as the new 1024 node Geological and Planetary Sciences Dell cluster, CITerra, available to us at Caltech. We will present results from the latter stages of model spin-up, and show that the model atmosphere (having been started from rest) takes many Titan years to reach an equilibrium state in which there is no net transfer of angular momentum from surface to atmosphere when averaged over one year. We will also show that our model begins to produce significant equatorial super-rotation after several years, and will identify the mechanism behind this in TitanWRF. Validation of the equilibrium model state is our next step once it is available, but we will also outline future plans after this has been accomplished. These include allowing advection of the radiatively active haze distribution by model winds, and the inclusion of simple methane microphysics to study cloud formation in Titan's lower atmosphere. This work is funded by NASA's AISR and OPR research programs. |
| Title: | VenusWRF: A New Venus GCM Using PlanetWRF |
|---|---|
| Authors: | Lee, Christopher; Richardson, M. I.; Newman, C.; Toigo, A. D. |
| Affiliation: | AA(California Institute of Technology), AB(California Institute of Technology), AC(California Institute of Technology), AD(Kobe University, Japan) |
| Journal: | American Astronomical Society, DPS meeting #38, #26.13; Bulletin of the American Astronomical Society, Vol. 38, p.526 |
| Publication Date: | Sep 2006 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2006: American Astronomical Society |
| Bibliographic Code: | 2006DPS....38.2613L |
| Abstract: | The NCAR terrestrial Weather Research and Forecast (WRF) atmospheric model has been converted into a global, planetary model. The model is fully compressible, has Coriolis and curvature treatment and has hydrostratic and non-hydrostatic options. The model has been converted for use on Venus, initally using the linearized forcing and dissipation parameterizations of recent Venus GCMs (Lee et al.(2005), Yamamoto and Takahashi (2003)). Preliminary analysis of the momentum transports, atmospheric circulation, and super-rotation diagnostics from this model will be presented. The next stage of the study will be to use more realistic thermal forcing data derived from radiative models, and to adapt a radiative transfer model for the Venus atmosphere in order to provide more realistic heating rates and allow radiative feedback processes to be included in the GCM. |
| Title: | Climate simulation of recent climate changes on Mars |
|---|---|
| Authors: | Mischna, M. A.; Richardson, M. I. |
| Journal: | Second workshop on Mars atmosphere modelling and observations, held February 2 7 - March 3, 2006 Granada, Spain. Edited by F. Forget, M.A. Lopez-Valverde, M.C. Desjean, J.P. Huot, F. Lefevre, S. Lebonnois, S.R. Lewis, E. Millour, P.L. Read and R.J. Wilson. Publisher : LMD, IAA, AOPP, CNES, ESA, 2006., p.312 |
| Publication Date: | Feb 2006 |
| Origin: | AUTHOR |
| Bibliographic Code: | 2006mamo.conf..312M |
| Abstract: | Not Available |
| Title: | Development of a new global, scalable and generic general circulation model for studies of the martian atmosphere |
|---|---|
| Authors: | Mischna, M. A.; Toigo, A. D.; Newman, C. E.; Richardson, M. I. |
| Journal: | Second workshop on Mars atmosphere modelling and observations, held February 2 7 - March 3, 2006 Granada, Spain. Edited by F. Forget, M.A. Lopez-Valverde, M.C. Desjean, J.P. Huot, F. Lefevre, S. Lebonnois, S.R. Lewis, E. Millour, P.L. Read and R.J. Wilson. Publisher : LMD, IAA, AOPP, CNES, ESA, 2006., p.113 |
| Publication Date: | Feb 2006 |
| Origin: | AUTHOR |
| Bibliographic Code: | 2006mamo.conf..113M |
| Abstract: | Not Available |
| Title: | Observations of Martian Clouds in the Polar Regions with THEMIS on board Mars Odyssey |
|---|---|
| Authors: | Inada, A.; Richardson, M. I.; Strausberg, M. J. |
| Journal: | 36th COSPAR Scientific Assembly. Held 16 - 23 July 2006, in Beijing, China. Meeting abstract from the CDROM, #2587 |
| Publication Date: | n/a 2006 |
| Origin: | ADS |
| Bibliographic Code: | 2006cosp...36.2587I |
| Abstract: | Many clouds and dust plumes have been observed in the Mars polar regions by the Mars Odyssey Thermal Imaging System THEMIS during the first mapping year Some of the clouds have clear edges that do not appear to be limited or constrained by topography Another type of clouds is formed in association with troughs Wave-pattern clouds are commonly seen there as previous missions have shown Dust plumes were captured near the southern permanent polar cap in summer They have distinctive roll features indicating the mixing turbulence pattern in the boundary layer when a strong wind is active The typical spacing of the rolls is about 650-700 m We will present a map of cloud plume types and their characteristics |