Carbon dioxide ice clouds, snowfalls, and baroclinic waves in the northern winter polar atmosphere of Mars

Abstract

The formation of CO2 ice clouds in the northern winter polar atmosphere of Mars and their relation to baroclinic planetary waves, which dominate local dynamics, are studied using a general circulation model. The simulation shows that clouds are formed at altitudes of up to ∼ 40 km, and their occurrence correlates to a large degree with the cold phases of transient planetary waves. Ice particles formed up to ∼ 20 km can reach the surface in the form of snowfall in certain longitude regions, while in others, these particles likely sublimate in the lower warmer atmospheric layers. The simulation suggests that about a half of the seasonal ice cap is created by CO2 snow, while the remaining half by direct condensation on the surface. Thus, the occurrences of ice clouds and rates of deposition are closely linked to traveling planetary waves, indicating the possibility for the reliable forecasts of CO2 snow storms.

Annual Cycle of Gravity Wave Activity Derived From a High‐Resolution Martian General Circulation Model

“…The MGCM employs the spectral dynamical core of the Model for Interdisciplinary Research On Climate terrestrial GCM, which was developed collaboratively by the Atmosphere and Ocean Research Institute, The University of Tokyo, the National Institute of Environmental Studies, and the Japan Agency for Marine‐Earth Science and Technology in Japan (K‐1 Model Developers, ; Sakamoto et al, ). The implemented physical parameterizations suitable for the Martian atmosphere have been described in detail in the works by Kuroda et al (, ). The lower‐resolution version of the MGCM has been validated against the observed zonal mean climatology (Kuroda et al, ) and applied for studies of baroclinic planetary wave activity (Kuroda et al, ), annular mode variability in the middle and high latitudes (Yamashita et al, ), equatorial semiannual oscillations (Kuroda et al, ), winter polar warmings during dust storms (Kuroda et al, ), and CO 2 snowfalls during northern polar winters (Kuroda et al, ).…”

“…The implemented physical parameterizations suitable for the Martian atmosphere have been described in detail in the works by Kuroda et al (, ). The lower‐resolution version of the MGCM has been validated against the observed zonal mean climatology (Kuroda et al, ) and applied for studies of baroclinic planetary wave activity (Kuroda et al, ), annular mode variability in the middle and high latitudes (Yamashita et al, ), equatorial semiannual oscillations (Kuroda et al, ), winter polar warmings during dust storms (Kuroda et al, ), and CO 2 snowfalls during northern polar winters (Kuroda et al, ). Recently, this model has been used for validating the temperature retrievals from the MGS radio occultations during the southern polar night (Noguchi et al, ), studying modulation of CO 2 clouds by stationary and transient waves (Noguchi et al, ), and exploring the influence of a global dust storm on the electron densities in the D region of the ionosphere (Haider et al, ).…”

The Stability of Mars’s Annular Polar Vortex

“…These form in both the Northern and Southern Hemispheres during their respective winters and are an important barrier for the mixing of polar and midlatitude air. As such, they act to intensify meridional temperature gradients, influence the rate of condensation of CO 2 onto the polar ice cap, and limit the transport of dust and ice aerosols toward polar regions (Colaprete et al 2008;Kuroda et al 2013;Guzewich et al 2016).…”

Role of stationary and transient waves in CO2 supersaturation during northern winter in the Martian atmosphere revealed by MGS radio occultation measurements

“…They found that the occurrence of condensation was very variable, even at the same latitudes in the northern hemisphere, attributing the northern seasonal variation in CO 2 condensation to multiple meteorological events, including the development of baroclinic waves. More detailed analyses for the relationship between transient waves and CO 2 supersaturation using observational data are needed to confirm the results suggested in Hu et al [] and Kuroda et al [].…”

“…Barnes [2006] and Barnes et al [2009] suggested that transient waves cause CO 2 condensation in the atmosphere. The results of a Martian General Circulation Model (MGCM) showed that baroclinic waves cause CO 2 supersaturation and condensation, which results in CO 2 clouds and even snowfall in the northern winter polar atmosphere [Kuroda et al, 2013]. Hu et al [2012] is a comprehensive study of CO 2 condensation on Mars.…”