Gale surface wind characterization based on the Mars Science Laboratory REMS dataset. Part I: Wind retrieval and Gale's wind speeds and directions

Abstract

The characterization of Martian surface winds as a function of time of day and season at one location can increase our knowledge of Mars surface conditions and assist in planning for future unmanned and manned missions. Martian surface winds vary greatly with location, and even at a particular landing site show a high degree of diurnal, seasonal, and interannual variability. Thus characterizing surface wind speeds and directions requires a long time series, which is rarely obtained on Mars. The Rover Environmental Monitoring Station (REMS) instrument on the Mars Science Laboratory (MSL) rover has been measuring Martian winds since 2012, thus has provided more than two Martian years of wind data at the first Martian landing site to have significant topography, in the trench of Gale Crater. Unfortunately, likely debris impacts during landing damaged the wind sensor, making it difficult to extract useful wind data. The first part of this paper presents a new retrieval that allows “good” wind measurements to be extracted from the raw dataset obtained under such conditions. In addition, a characterization of wind speeds and directions in Gale Crater is presented, after processing the full dataset of wind data in order to obtain the representative winds for different diurnal timeslots and seasons. Results suggest complex wind patterns and great variability depending on local time and season. Also, a significant influence by the synoptic scale circulation in the wind patterns is observed, although the local-scale circulation is suggested to be the major contributor to the observed surface winds in Gale Crater.