HR: 1340h
AN: P23A-1085    [Abstracts]
TI: New Mars Water Cycle Simulations Constrained by Laboratory Microphysical Results
AU: * Colaprete, A
EM: Anthony.Colaprete-1@nasa.gov
AF: NASA Ames Research Center, Moffett Field, MS 245-3, Mountain View, CA 94035-1000, United States
AU: Iraci, L T
EM: Laura.T.Iraci@nasa.gov
AF: NASA Ames Research Center, Moffett Field, MS 245-3, Mountain View, CA 94035-1000, United States
AU: Phebus, B D
EM: phebuscouple@hotmail.com
AF: San Jose State University, One Washington Square, San Jose, CA 95192, United States
AB: Water ice clouds have an important role within the martian climate. While these clouds in general contain much less water mass and are optically thinner than their terrestrial counterparts, the thin martian atmosphere is very susceptible to their radiative effects. Furthermore, water ice clouds have a critical role in moderating the atmospheric transport of water vapor (via sedimentation of cloud particles) and dust (via scavenging of dust as cloud nuclei). Understanding the current climate of Mars and its water cycle requires a thorough understanding of martian water ice clouds. The microphysical processes that govern their formation and growth largely determine the effective role of water ice clouds. However, in most studies of martian water ice clouds these microphysics have been either neglected or greatly simplified. In those models that do attempt a more detailed treatment of cloud growth, the implementation of the critical parameters most important to martian clouds, namely the critical supersaturation, contact parameter and growth rate, is still handicapped by having only terrestrial analogs and data sets from which to derive constraints. The work presented here utilizes new laboratory measurements of cloud formation and growth in martian conditions to constrain a sophisticated hybrid-moment cloud model incorporated into the NASA Ames GCM. Significant differences are seen between water cycle predictions using traditional assumptions to those using the new cloud model and laboratory constraints. These differences, including changes in total water vapor and cloud column amount and surface frost distribution and seasonality, and the implication to water cycle processes and observations will be discussed.
DE: 3311 Clouds and aerosols
DE: 3337 Global climate models (1626, 4928)
DE: 5210 Planetary atmospheres, clouds, and hazes (0343)
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting