...
首页> 外文期刊>Planetary and space science >Water vapor saturation and ice cloud occurrence in the atmosphere of Mars
【24h】

Water vapor saturation and ice cloud occurrence in the atmosphere of Mars

机译:Water vapor saturation and ice cloud occurrence in the atmosphere of Mars

获取原文
获取原文并翻译 | 示例
           

摘要

We investigate water vapor saturation in the martian atmosphere in the presence or proximity of water ice clouds. We evaluate mixing ratio profiles of ambient water vapor derived from measurements by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the Nadir and Occultation for MArs Discovery (NOMAD) instrument in comparison with saturated vapor mixing ratio profiles derived from co-located temperature measurements by the Mars Climate Sounder (MCS). We find that during the aphelion season the average saturation state of the atmosphere is close to saturation in the presence of clouds, with supersaturation ratios reaching values of no more than two to three towards the top of the cloud layer. During the perihelion season, subseasonally averaged water vapor is close to saturation or somewhat subsaturated in the presence of clouds, with some supersaturation at southern high latitudes towards the top of the clouds. Measurements at northern mid- to high latitudes during a Global Dust Storm suggest a shift of the cloud occurrence to higher altitudes but exhibit a similar saturation structure, with supersaturations not exceeding a ratio of five. The atmosphere above cloud layers is largely subsaturated, suggesting that cloud formation is fairly instantaneous upon the temperature dropping below the frost point and high levels of supersaturation are not required to form water ice clouds. We propose a schematic model of cloud evolution in which small cloud particles are formed rapidly in slightly supersaturated regions, and then fall and grow such that ice opacity is still observed even in the subsaturated regions below.

著录项

获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号