Sub‐Hourly Observations of Dust Storm Growth, Lee Waves, and Lyot Crater, by the EMM Camera EXI

We explore a sequence of 13 unique high‐cadence images of a dust storm, from the Emirates Mars Mission (EMM). The Emirates eXploration Imager camera took these images in less than 8 hr on 18 December 2022 (Martian Year 36, solar longitude 356°). Most of these images are separated by a time difference of half an hour. The region of interest extends from Lyot crater to the east. During the morning, the EMM images show lee waves (atmospheric gravity waves). In the late morning, the lee waves rapidly change into clearly distinct dust storm texture/convective features. We track the evolution of both lee waves and a local dust storm between sunrise and mid‐afternoon. Also, we relate our observations to atmospheric dynamics. Our analysis is supported by the Mars Climate Database and radio occultation measurement data. Plain Language Summary The Emirates Mars Mission (EMM) has an on‐board camera, whose images from 18 December 2022 show a dust storm near Lyot crater (a large crater in the northern hemisphere of Mars). An image was taken almost every half an hour. In total, this gave 13 camera images in less than 8 hr. This number of images in such a short time is unique. The images reveal clouds which form straight lines during the morning. Such straight clouds are known as “lee wave clouds.” In the late morning, the lee waves disappear quickly and a quite different dust cloud appears. The latter is a dust storm which grows quickly. We follow the lee waves and dust storm from sunrise to mid‐afternoon. Also, we put our observations into the context of physical processes in the Mars atmosphere. Our work is supported by external data and measurements. That is to say data from the Mars Climate Database and radio occultation measurements. Key Points The Emirates Mars Mission provided thirteen (sub‐)hourly images; they show variations in clouds and atmospheric dust on 18 December 2022 The image sequence tracks the evolution of both lee waves and a local dust storm between sunrise and mid‐afternoon, near Lyot Crater We relate our observations to atmospheric dynamics, supported by the Mars Climate Database and radio occultation measurements