Abstract

This project uses the Earth System Modeling Framework (ESMF) and InterComm to produce a TIME-GCM and CAM coupled model. This project will demonstrate a new ESMF capability for coupling models running as separate executables. This capability is based on the InterComm library. InterComm is a runtim... Show moreThis project uses the Earth System Modeling Framework (ESMF) and InterComm to produce a TIME-GCM and CAM coupled model. This project will demonstrate a new ESMF capability for coupling models running as separate executables. This capability is based on the InterComm library. InterComm is a runtime library and programming model for coupling separately executing parallel (and sequential programs), and is being used as the component coupling technology within the NSF Center for Integrated Space Weather Modeling. ESMF interfaces to InterComm have been contributed to the ESMF code repository, making it easy to use InterComm to transfer data into and out of ESMF components such as CAM. This project's work to couple TIME-GCM and CAM is motivated by the goal of understanding the day-to-day behavior of the ionosphere-thermosphere system. Doing this requires unraveling the relative strengths of forcing mechanisms of the I-T system, including solar ultraviolet, extreme-ultraviolet, and X-ray fluxes, magnetospheric processes resulting in geomagnetic activity and auroral effects, and propagation of dynamical variations driven by lower atmosphere weather and middle atmosphere tides. The National Center for Atmospheric Research (NCAR) Thermosphere - Ionosphere - Mesosphere -Electrodynamic - Global Circulation Model (TIME-GCM) is used to simulate this region depending on its forcing by the Sun. Recent work on improving the forcing of this model by including an improved description of the Extreme Ultra Violet (EUV) radiation has increased its ability to predict observed parameters such as satellite drag, but it does not capture all the observed hemispheric asymmetries. The implication is that forcing from the lower atmosphere, which is clearly asymmetric due to the location of continental masses, and is known to have very different dynamical features at solstices, is controlling the thermosphere. However, the TIME-GCM, with its 30-km lower boundary, does not contain these effects. The Community Atmosphere Model (CAM) simulates the variation in the atmosphere, and by coupling it to the TIME-GCM we plan to investigate how much of these asymmetries can be addressed by this forcing from below. Show less