WSA-Enlil-Cone Transition to Operations at NWS/SWPC

The National Weather Service's (NWS's) Space Weather Prediction Center (SWPC) is transitioning the first large-scale, physics-based space weather prediction model into operations on the NWS National Centers for Environmental Prediction supercomputing system. The model is intended to provide 1-4 day advance warning of quasi-recurrent solar wind structures and Earth-directed coronal mass ejections (CMEs). Travelling solar disturbances have long been known to disrupt communications, wreak havoc with geomagnetic systems, and to pose dangers for satellite operations. A team has been put together at SWPC to bring an advanced numerical model, well-developed within the research community, to bear upon forecasting these space weather hazards.

The modeling system consists of two main parts: 1) a semi-empirical near-Sun module that approximates the outflow at the base of the solar wind; and 2) a sophisticated 3-D magnetohydrodynamic numerical model that simulates the resulting flow evolution out to Earth. The former module is driven by observations of the solar surface magnetic field, as taken over a solar rotation and composited into a synoptic map; this input is used to drive a parameterized near-Sun expansion of the solar corona, which is subsequently input into the second, interplanetary module to compute the quasi-steady (ambient) solar wind outflow. Finally, when an Earth-directed CME is detected, coronagraph images from NASA spacecraft are used to characterize the basic properties of the CME, including timing, location, direction, and speed. This input (the “cone” model) is injected into the pre-existing ambient conditions, and the subsequent transient evolution forms the basis for the prediction of the CME arrival time at Earth, its intensity, and its duration.

Steps necessary to acquire and test the models, to assure robust access to the observational inputs, and to develop the requisite computational, communications, and archival infrastructure are well underway. SWPC forecasters are being trained in the full process of creating CME inputs, interpreting the standard and specialized outputs from the model, and melding them into a coherent and informative forecast product. The initial version of the full system is on schedule to enter operational evaluation at the end of FY11.