SIParCS 2017- Manuel Valera
Vertical Remapping and Energy Conservation in the Community Atmosphere Model, CAM
This research implemented and tested different remapping techniques in CAM to understand and correct numerical errors that occur at the top of the atmosphere and at steep gradients. By modifying the effects of boundary conditions in the CAM remapping routines, we reduced current aberrations by up to 60%. We explored an alternative way to compute and remap the total energy budget of the system, and it conserved energy to machine precision. However, its numerical limitations, greater remapping errors, and never-before-documented artifacts disqualified it as a replacement for the energy conservation formula in older versions of CAM. We also implemented a hierarchy of remapping algorithms in CAM and analyzed its effects on gradient mixing under Aquaplanet and Held-Suarez test cases, including the sixth-order-accurate Piecewise Quartic Method, which is now fully implemented into CAM from Modular Ocean Model routines. Our methods enabled us to remap vertically with unprecedented accuracy on CAM, as well as conserving gradient structures.
Mentors: Peter Lauritzen and Ram Nair