New Astronomy in the COLA Atmospheric General Circulation Model

Abstract

Two new astronomy packages, Naval Observatory Vector Astrometry Subroutines/Jet Propulsion Laboratory (NOVAS/JPL) and Berger (1978), have been installed in the Center for Ocean-Land-Atmosphere Studies (COLA) atmospheric general circulation model (AGCM). These provide much greater accuracy and flexibility in representing the Sun’s position as seen by the Earth’s atmosphere in both realistic settings as well as those involving paleoclimate simulations and constrained astronomical parameter experiments. Their computational efficiency provide low cost for any period of time being simulated. Details and implementation are discussed. The errors are also reviewed and comparisons are made with the original Spencer (1971) astronomy calculation. The accuracy and speed these new codes obtain make them well suited for installation into any AGCM.