CMAM30 output

CMAM30 is a project funded by the Canadian Space Agency which uses the Canadian Middle Atmosphere Model (CMAM) in a nudged configuration to provide a retrospective estimate of the chemical and dynamical evolution of the atmosphere over the period 1981-2011 ^{Footnote 1 Footnote 2} . CMAM is a well-established high-top chemistry-climate model whose performance has been extensively assessed. This nudged configuration exploits the fact that chemical fields throughout the atmosphere are slaved to the meteorology, while the large-scale dynamics of the mesosphere is largely driven by variations in the troposphere and stratosphere. Therefore, by nudging the meteorological state of the troposphere and stratosphere to a high-quality reanalysis (ERA-Interim in this case), CMAM can be used to "predict" the chemical fields throughout the atmosphere and the dynamical state of the mesosphere on a day-to-day basis over this period. To the extent that ERA-Interim has good long-term stability, the same should be true of the CMAM30 product.

This data set is expected to be useful for measurement scientists interested in correlative data, as well as those interested in variability and long-term changes of atmospheric composition in the troposphere-stratosphere-mesosphere system, or dynamical aspects of the mesosphere and MLT region.

There are two data sets: one from the regular CMAM (with a lid around 95 km) focused on the troposphere-stratosphere-mesosphere system, and another from the extended CMAM (with a lid around 200 km) focused on the MLT region.

To facilitate the analysis of stratospheric trends, the temperature field of the reference ERA-Interim data set used for the nudging of the CMAM was adjusted over its top four pressure levels (1, 2, 3, and 5hPa) to remove temporal discontinuities that occured in 1985 and 1998. Aditional information and the specific correction used for CMAM30 are provided in the CMAM30 ERA-Interim Adjustments section ^{Footnote 3} .

We invite interested scientists to analyze these data. Publications can be developed using this data, however we would ask that a member of the CMAM30 team be consulted and possibly included as a co-author to ensure proper liaison in case any issues arise.