Ice nucleation by surrogates of Martian mineral dust: What can we learn about Mars without leaving Earth?
| Autor: | Daniel J. Cziczo, Jonathan P. D. Abbatt, Sarvesh Garimella, Harald Saathoff, Michael Raddatz, Ottmar Moehler, Martin Schnaiter, Kristina Hoehler, Luis A. Ladino |
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| Rok vydání: | 2013 |
| Předmět: |
Martian
Mars Exploration Program Atmosphere of Mars Mineral dust Atmospheric sciences Physics::Geophysics Astrobiology Geophysics Space and Planetary Science Geochemistry and Petrology Liquid water content Physics::Space Physics Earth and Planetary Sciences (miscellaneous) Ice nucleus Cirrus Martian polar ice caps Astrophysics::Earth and Planetary Astrophysics Astrophysics::Galaxy Astrophysics Physics::Atmospheric and Oceanic Physics Geology |
| Zdroj: | Journal of Geophysical Research: Planets. 118:1945-1954 |
| ISSN: | 2169-9097 |
| DOI: | 10.1002/jgre.20155 |
| Popis: | [1] Water and carbon dioxide ice clouds have been observed in the Martian atmosphere where they are dynamic parts of that planet's water and carbon cycles. Many Martian atmospheric models struggle to correctly predict clouds and, with insufficient data, some use untested simplifications that cloud formation occurs exactly at the saturation point of the condensed phase or at the same conditions as terrestrial cirrus clouds. To address the lack of data, we have utilized an 84 m3 cloud chamber built for studies of high altitude cirrus and polar stratospheric ice clouds in the Earth's atmosphere and adapted to Martian conditions. Using this chamber, we have been able to produce water ice clouds from aerosol in an inert and low pressure atmosphere mimicking that of Mars. At temperatures between 189 and 215 K, we investigated cloud formation by mineral dust particulates of a similar composition and size to those found on Mars. We show that these surrogate materials nucleate effectively at the higher temperatures, with minor temperature dependence at saturations ratios with respect to the ice phase of ~1.1, similar to what has been found for terrestrial cirrus. At the lower end of the temperature range, this saturation rises to ~1.9, a result consistent with previous studies. |
| Databáze: | OpenAIRE |
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