Glaciation of Mars from 10 million years ago until 10 million years into the future simulated with the model MAIC-2

Greve, Ralf; Grieger, Björn; Stenzel, Oliver J.

doi:10.5281/zenodo.3698542

Glaciation of Mars from 10 million years ago until 10 million years into the future simulated with the model MAIC-2

Greve, Ralf; Grieger, Björn; Stenzel, Oliver J.

Publisher: Zenodo
DOI: 10.5281/zenodo.3698542
Repository: zenodo.org
Language: en

Abstract

Presentation No. PPS03-06, JpGU Meeting 2012, Makuhari Messe, Chiba, Japan, 24 May 2012. Abstract. The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model that consists of a set of parameterizations for the surface temperature, the atmospheric water transport and the surface mass balance (deposition minus sublimation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude (Ls) of perihelion. Surface temperature is described by the Local Insolation Temperature (LIT) scheme, which uses a daily and latitude-dependent radiation balance. The sublimation rate of water is calculated by an expression for free convection, driven by density differences between water vapour and ambient air, the deposition rate follows from the assumption that any water vapour that exceeds the local saturation pressure condenses instantly, and atmospheric transport of water vapour is approximated by instantaneous mixing with a prescribed north-south gradient. Glacial flow of ice deposits is neglected. Simulations from 10 million years (Ma) ago until 10 Ma into the future predict a variable glaciation with two distinct stages. Stage 1, the period of high average obliquity prior to 4 Ma ago, is characterized by a very mobile glaciation all over the planet. During stage 2, from 4 Ma ago until today, the north polar ice deposits grow essentially monotonically; however, interrupted by erosional events at ~3.2, 1.9 and 0.7 Ma ago (when maximum amplitudes of the main 125-ka obliquity cycle occur). There is no significant new ice deposition in the south. Stage-2-like behaviour is predicted to continue into the future.

Full text

Glaciation of Mars from 10 million years ago until 10 million years into the future simulated with the model MAIC-2 Ralf Greve1, Björn Grieger2, Oliver J. Stenzel3 HST image, April/May 1999. Credit: S. Lee, J. Bell, M. Wolff, NASA. 1 Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan 2 European Space Astronomy Centre, Madrid, Spain 3 Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany Presentation No. PPS03-06, JpGU Meeting 2012, Makuhari Messe, Chiba, Japan, 24 May 2012 Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 2 Background Mars experiences large periodic changes of the orbital elements (obliquity, eccentricity, equinox precession) Climate change (like on Earth, Milankovitch cycles) Redistribution of water ice (surface/subsurface, high/mid/low latitudes) Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 3 Background •Orbital parameters by Laskar et al. (2004) from t= –20 Ma until t= +10 Ma. •Main driving force for changes: Obliquity φ(= axial tilt). N S φ Stage 1 Stage 2 Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 4 Scientific questions re water ice deposits •What is the history of the Martian water ice deposits? In particular, how did they evolve during the high-obliquity stage 1? •Can we understand the present-day situation? (Polar layered deposits = PLDs, absence of notable surface ice deposits elsewhere.) •How will the present-day PLDs evolve into the future? Are they expected to grow or to shrink, and what are the consequences for water ice deposits elsewhere on the planet? Does glacial flow play a role in their evolution? Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 5 Model MAIC-2 MMars AAtmosphere IIce CCoupler (Version 2) (Greve, Grieger and Stenzel, 2010) Purpose: Modelling the Martian glaciation (H2O ice) over climatic time scales Forcing: Directly driven by orbital parameters: obliquity, eccentricity and Lsof perihelion (Laskar et al., 2004) Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 6 Surface temperature: LIT scheme (LIT = Local Insolation Temperature) •Orbital parameters → daily mean insolation flux F. •Radiation balance: •However, this does not account for the secondary condition due to CO2condensation → latent heat flux into and from the seasonal CO2caps taken into account. Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 7 Surface temperature: LIT scheme Daily mean surface temperature for presentday conditions: Mars Climate Database (Lewis et al. 1999): K K Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 8 Evaporation (sublimation) •Parameterisation by Ingersoll (1970); additional dust insulation factor E0< 1. •Result: Strong temperature dependence, slight pressure dependence. E0= 0.1 Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 9 Condensation (deposition) •Any water vapour that exceeds the local saturation pressure condenses instantly and is deposited as H2O ice. •Instantaneous mixing on a time-scale of several days →uniform distribution of atmospheric water all over the planet. Water transport in the atmosphere Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 16 Ice deposits from t= –7.5 Ma until t= 0 t= –7.5 Ma Vertical exaggeration factor 750 Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 17 Ice deposits from t= –7.5 Ma until t= 0 t= 0 (today) Vertical exaggeration factor 750 HNP = 2.256 km (obs. 2.367 km) VNPLD = 8.0394 x 105km3(obs. 8.0355 x 105km3) (without the basal unit; T. C. Brothers and J. W. Holt, pers. comm. 2012) Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 18 NPLD from t= –5 Ma until t= 0 Erosional events at about –3.2, –1.9 and –0.7 Ma, essentially consistent with radar stratigraphy (Holt el al., LPSC Abstract 2012) Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 19 NPLD/SPLD from t= 0 until t=+10 Ma Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 20 Summary •Prior to 4 Ma ago (“stage 1”): very mobile glaciation all over the planet. •Since 4 Ma ago and into the future (“stage 2”): essentially monotonically growing NPLD, no significant new ice deposition in the south. •Past erosional events to first order consistent with radar stratigraphy, similar events predicted for the future. Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 21 Acknowledgements •DFG (German Science Foundation) Priority Programme “Mars and the Terrestrial Planets”. •ILTS Research Fund. MAIC-2 code available as free software (GNU GPL) at http://maic2.greveweb.net/. ご清聴ありがとうございます。 Thank you! Appendix Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 24 Surface temperature: LIT scheme •Seasonal cap at latitude ϕ assumed to exist between the onset of the polar night (tdusk) and an unknown time tafter the end of the polar night (tdawn). •Condensation during polar night: •Evaporation after dawn: •The time tat which CO2is completely evaporated follows from Glaciation of Mars simulated with MAIC-2 Greve, Grieger and Stenzel 25 Evaporation •Daily cycle of the surface temperature taken into account for computing the evaporation rate: Approximates measured data from Pathfinder, Viking Landers 1, 2 and Phoenix.