MARS CLIMATE DATABASE v1.0 CRITICAL REVIEW (ESTEC Contract 11369/95/NL/JG)

This document compares the MCD with such observational data as is available concerning the atmosphere of Mars and with previous martian atmospheric models which have been developed for similar purposes, such as MarsGRAM (Justus, 1990). More detailed descriptions of the models used to compile the MCD and of the validation procedures are available in other documents and publications relating to this project (Collins and Lewis, 1997a, 1997b; Collins et al., 1996; Hourdin et al., 1996; Read et al., 1996, 1997). Note: This document refers to the first release of the Mars Climate Database (MCDv1.0). Future releases will contain updates to the database, to the access software and to the documentation. If you have any queries, or if you want to find out if this is the latest version of the MCD please email euromars@lmd.ens.fr. 2 Comparison with Observations Such observational evidence from the Martian atmosphere as is available and relevant is briefly reviewed in this section and compared where possible with the data contained in the Martian Climate Database and with results from the General Circulation Models which were used in its compilation. 2.1 Dust Distribution The major factor which governs the inter-annual variability in the martian atmosphere is the amount and distribution of suspended dust. The MCD was compiled with four dust scenarios, two multi-annual simulations for years with constant low dust amounts or moderate dust loading as observed by the Viking landers, and two different seasonal global dust storm scenarios (dust optical depth, ø = 2 and ø = 5). There does indeed appear to be evidence that some martian years are colder (and by implication less dusty), such as the Mariner 9 year and some more recent observations, and some are warmer (and imply more dust in t..