A32F-07
Better Understanding Transport Related Differences Between CCMs and Trace Gas Measurements With an Idealized Stratospheric Model
Wednesday, 16 December 2015: 11:50
3010 (Moscone West)
Eric A Ray1,2, Fred L Moore3, Karen Hepler Rosenlof2, David A. Plummer4, Felicia Kolonjari5 and Kaley A Walker6, (1)University of Colorado at Boulder, Boulder, CO, United States, (2)NOAA ESRL CSD, Boulder, CO, United States, (3)NOAA/ESRL, Boulder, CO, United States, (4)Environment Canada, Victoria, BC, Canada, (5)University of Toronto, Toronto, ON, Canada, (6)University of Toronto, Department of Physics, Toronto, ON, Canada
Abstract:
We use a modified version of the tropical leaky pipe (TLP) model of the stratosphere to explore how well an idealized model can (1) reproduce global chemistry-climate model (CCM) output and (2) constrain transport characteristics necessary to replicate measurements of long-lived trace gases. The version of the TLP model we use includes the simulation of long-lived trace gases, such as SF6 and CO2, as well as photochemically active trace gases such as CFC-11, CFC-12 and N2O. The TLP model was found to accurately replicate trace gas output from the Canadian Middle Atmosphere Model (CMAM) for time-averaged profiles in the tropics and each extratropical region. With confidence that the TLP model could represent the basic transport features in CMAM we then used the TLP model to interpret differences between ACE satellite and balloon measurements and CMAM output. The TLP model is shown to uniquely determine mean circulation and recirculation (mixing between the extratropics and tropics) changes necessary for CMAM to more accurately simulate the measurements. This guidance on transport changes is novel, and cannot readily be obtained from direct comparison of CCM output with measurements. The TLP model can thus be used as a bridge between measurements and CCMs to allow more targeted modification of the CCMs than would otherwise be possible.
