{"title":"Seasonal and interannual variability of the water vapor vertical distribution in the Martian lower atmosphere","authors":"","doi":"10.1016/j.icarus.2024.116360","DOIUrl":null,"url":null,"abstract":"<div><div>We apply a novel method to retrieve water vapor vertical distributions in the Martian atmosphere to spectra collected by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES). The new method exploits differences in sensitivity of the daytime and nighttime TES nadir spectra to water vapor content in different parts of the lower atmosphere (0–40 km). Based on the test retrievals from simulated environments, vertical profiles of water vapor can be retrieved with accuracy ∼20–40 % depending on the season and altitude above surface. Retrievals from observations collected by the MGS TES between L<sub>s</sub> = 135° in MY24 and L<sub>s</sub> = 75° in MY27 enable exploration of the seasonal and interannual variabilities of the vertical distribution of water vapor. Retrieved vapor distributions and their seasonal variability are generally consistent with those predicted by a numerical circulation model. Vapor is concentrated near the surface in the northern polar region and the mid-latitudes during the northern summer (L<sub>s</sub> = 90°). During the southern summer (L<sub>s</sub> = 270°) vapor extends higher in the atmosphere in the southern polar region, reflecting both sublimation of the seasonal surface ice and atmospheric transport by the upper branch of the southern Hadley cell. During both equinoxes (L<sub>s</sub> = 0° and L<sub>s</sub> = 180°) vapor is found in the lower part of the tropical atmosphere. At the same time the retrieved vertical distributions exhibit notable interannual variability. Following the global dust storm of MY25, vapor is confined to lower altitudes in the southern polar region during the southern summer. During the southern spring in MY26 (L<sub>s</sub> = 180°-270°) vapor extends higher in the atmosphere and mixing ratios increase faster with height at the equator and in the northern tropics. These examples suggest that Martian atmosphere may experience interannual changes in the atmospheric transport, some of which could be in response to global dust storm events.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Icarus","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0019103524004202","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
We apply a novel method to retrieve water vapor vertical distributions in the Martian atmosphere to spectra collected by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES). The new method exploits differences in sensitivity of the daytime and nighttime TES nadir spectra to water vapor content in different parts of the lower atmosphere (0–40 km). Based on the test retrievals from simulated environments, vertical profiles of water vapor can be retrieved with accuracy ∼20–40 % depending on the season and altitude above surface. Retrievals from observations collected by the MGS TES between Ls = 135° in MY24 and Ls = 75° in MY27 enable exploration of the seasonal and interannual variabilities of the vertical distribution of water vapor. Retrieved vapor distributions and their seasonal variability are generally consistent with those predicted by a numerical circulation model. Vapor is concentrated near the surface in the northern polar region and the mid-latitudes during the northern summer (Ls = 90°). During the southern summer (Ls = 270°) vapor extends higher in the atmosphere in the southern polar region, reflecting both sublimation of the seasonal surface ice and atmospheric transport by the upper branch of the southern Hadley cell. During both equinoxes (Ls = 0° and Ls = 180°) vapor is found in the lower part of the tropical atmosphere. At the same time the retrieved vertical distributions exhibit notable interannual variability. Following the global dust storm of MY25, vapor is confined to lower altitudes in the southern polar region during the southern summer. During the southern spring in MY26 (Ls = 180°-270°) vapor extends higher in the atmosphere and mixing ratios increase faster with height at the equator and in the northern tropics. These examples suggest that Martian atmosphere may experience interannual changes in the atmospheric transport, some of which could be in response to global dust storm events.
期刊介绍：
Icarus is devoted to the publication of original contributions in the field of Solar System studies. Manuscripts reporting the results of new research - observational, experimental, or theoretical - concerning the astronomy, geology, meteorology, physics, chemistry, biology, and other scientific aspects of our Solar System or extrasolar systems are welcome. The journal generally does not publish papers devoted exclusively to the Sun, the Earth, celestial mechanics, meteoritics, or astrophysics. Icarus does not publish papers that provide "improved" versions of Bode''s law, or other numerical relations, without a sound physical basis. Icarus does not publish meeting announcements or general notices. Reviews, historical papers, and manuscripts describing spacecraft instrumentation may be considered, but only with prior approval of the editor. An entire issue of the journal is occasionally devoted to a single subject, usually arising from a conference on the same topic. The language of publication is English. American or British usage is accepted, but not a mixture of these.
京公网安备 11010802042870号
京ICP备2023020795号-1
分享
求助内容：
应助结果提醒方式：
扫码关注我们
