Mars Science Laboratory diurnal moisture observations and column simulations

摘要

Hourly observations of air temperature and relative humidity at 1.6m height from the surface(T 1.6m, RH 1.6m) measured by the Mars Science Laboratory (MSL) Rover Environmental Monitoring Station relative humidity (REMS-H) device are shown for MSL solar days 15–17 and 80–82, augmented with column model simulations. The diurnal range of T 1.6mwas 197–268 K in the first period, RH 1.6mbeing small (<1%) in daytime but increasing to 45–49% by sunrise. During the warmer second period the T 1.6m range was 201–275 K with RH 1.6m only up to 16% in the morning. The modeled temperatures were quite close to those observed when the local albedo was set to 0.15 and thermal inertia to 300 tiu. The modeled RH 1.6m was close to that observed when the well-mixed boundary layer values (0–4 km) of the mass mixing ratio q were 28–30ppmm (suggesting a precipitable water content (PWC) of ~5.5 μm) during the first period and 12 ppmm (PWC of ~2 μm) during the second period. The REMS-H observations indicate systematic diurnal variation in the near-surface mixing ratio.