The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

Abstract

We analyze the complete set of in-situ meteorological data obtained from the Viking landers in the 1970s to today's Curiosity rover to review our understanding of the modern near-surface climate of Mars, with focus on the dust, CO 2 and H 2 O cycles and their impact on the radiative and thermodynamic conditions near the surface. In particular, we provide values of the highest confidence possible for atmospheric opacity, atmospheric pressure, near-surface air temperature, ground temperature, near-surface wind speed and direction, and near-surface air relative humidity and water vapor content. Then, we study the diurnal, seasonal and interannual variability of these quantities over a span of more thanThe original version of this article was revised because due to an unfortunate turn of events a wrong value was published in Table 1. The resolution of the PHX pressure sensor was published as "0.1 mbar" whereas this value has now been corrected to "0.1 Pa" which is the correct value and should be regarded as the final version by the reader. B G.M. Martínez

Viking‐2 Seismometer Measurements on Mars: PDS Data Archive and Meteorological Applications

“…As can be seen there, and was noted in Anderson et al (, p. 4532), the calibration pulse values change by about 18% over the first 140 sols (see also their Appendix A2)—the evolution is due to declining temperatures affecting the coil resistance. By sol 400, air (see, e.g., Martínez et al, , Figure 5) and lander temperatures were rising again and the calibration pulse amplitude begins to decline.…”

“…The meteorology instrument on Viking included air and ground temperature sensors, a pressure sensor, and a wind speed and direction sensor. The instrumentation and results are described in Hess et al (), Sutton et al (), Tillman et al (, ), and Murphy et al (): see also Martínez et al (). Meteorology data were not always acquired at a high rate and not always when the seismometer was operating (a total of about 1.35 million meteorology readings were taken during the first 560 sols, at intervals varying from hours down to 4 s).…”

On the relationship between dust devil radii and heights

“…For instance, Equation 11 shows that, given a measured height, a devil's radius depends on the atmospheric scale height. As the martian atmosphere heats and cools during the day, the scale height waxes and wanes, and so the radius-height relationship, as probed at different times of day, should measurably shift and constrain the near-surface heat budget (Martínez et al 2017). Optical depth for devils with a given (or a narrow range of) properties may vary from region to region, depending on the availability of dust (Bandfield 2002), and provide input to models of the dust cycle.…”

Spatial, Seasonal, and Solar Cycle Variations of the Martian Total Electron Content (TEC): Is the TEC a Good Tracer for Atmospheric Cycles?

“…This is a consequence of the CO 2 condensation that every winter occurs at high latitudes and the subsequent sublimation during the spring and summer seasons. This cycle induces a large semiannual variation in the daily averaged surface pressure all over the planet (Figure 1d; e.g., Forget et al, 2007;Martínez et al, 2017). Another case related to the CO 2 cycle is the water cycle in which water vapor is released into the atmosphere from the polar caps during spring and mainly summer when the CO 2 ice layer has disappeared and a water ice layer is exposed to the atmosphere.…”