[
    {
        "id": "thesis:7435",
        "collection": "thesis",
        "collection_id": "7435",
        "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:01242013-162910396",
        "type": "thesis",
        "title": "Change in the Martian Atmosphere",
        "author": [
            {
                "family_name": "Kass",
                "given_name": "David M.",
                "clpid": "Kass-David-M"
            }
        ],
        "thesis_advisor": [
            {
                "family_name": "Ingersoll",
                "given_name": "Andrew P.",
                "clpid": "Ingersoll-A-P"
            },
            {
                "family_name": "Yung",
                "given_name": "Yuk L.",
                "clpid": "Yung-Y-L"
            }
        ],
        "thesis_committee": [
            {
                "family_name": "Unknown",
                "given_name": "Unknown"
            }
        ],
        "local_group": [
            {
                "literal": "Astronomy Department"
            },
            {
                "literal": "div_gps"
            }
        ],
        "abstract": "<P>There are several lines of evidence that the atmosphere of Mars has significantly\r\nevolved over the history of the planet. Because Mars does not have a strong intrinsic\r\nmagnetic field, the atmosphere is eroded by interactions with the solar wind. Conditions\r\nin the early solar-system significantly enhanced this loss, notably the component\r\ndue to solar-wind induced sputtering away. Modeling indicates that, integrated over\r\nthe last 3.5 billion years, 0.8 bars of CO_2 have been sputtered. This is accompanied by\r\nthe loss of 50 m of water. The loss of CO_2 is a significant loss when compared to the\r\nestimates of the thickness of the early atmosphere. A simple model of the behavior of\r\nthe atmospheric \u03b4^(13)C, based on the expected Martian carbon \"cycle\" constrains the\r\nsize the current CO_2 reservoirs by putting the sputtering loss into the context of the\r\nevolution of the atmosphere. In order to balance the isotopic effects of the sputtering\r\nloss, it is necessary for there to be ~ 100 mbars of CO_2 trapped in the planet. This\r\nis quite reasonable given the ability of the regolith to hold adsorbed CO_2. </P>\r\n\r\n<P>Using a modified form of Optimal Interpolation, it is possible to assimilate Thermal\r\nEmission Spectrometer (TES) observations from the Mars Global Surveyor (MGS)\r\nspacecraft into the Ames Mars General Circulation Model (MGCM). The method is\r\noptimized for the assimilation of the irregular data obtained during the aerobraking\r\nphase of the mission. Based on 25 sols of data at L_s \u2248 200, the assimilation process\r\nreveals several interesting features of the Martian atmosphere. The assimilation indicates\r\nthat the lower atmosphere (up to ~ 0.1 mbar) in the northern polar regions is\r\nvery cold-probably at or close to the CO_2 condensation temperature. Furthermore,\r\nthe data imply that the midlatitudinal westerly jets extend poleward of the indicated\r\nMGCM locations. In addition to correcting the phasing of the Northern baroclinic\r\nstorm belt, the data indicate that the amplitude of the waves are stronger than expected\r\nand possibly with a lower zonal wavenumber. Thus the data and assimilation\r\nallows the MGCM to create the 1997 Martian Fall instead of a random Fall. </P>\r\n",
        "doi": "10.7907/1mbp-xd62",
        "publication_date": "1999",
        "thesis_type": "phd",
        "thesis_year": "1999"
    }
]