An operational solar wind prediction system transitioning fundamental science to operations

Abstract

We present in this paper an operational solar wind prediction system. The system is an outcome of the collaborative efforts between scientists in research communities and forecasters at Space Environment Prediction Center (SEPC) in China. This system is mainly composed of three modules: (1) a photospheric magnetic field extrapolation module, along with the Wang-Sheeley-Arge (WSA) empirical method, to obtain the background solar wind speed and the magnetic field strength on the source surface; (2) a modified Hakamada-Akasofu-Fry (HAF) kinematic module for simulating the propagation of solar wind structures in the interplanetary space; and (3) a coronal mass ejection (CME) detection module, which derives CME parameters using the ice-cream cone model based on coronagraph images. By bridging the gap between fundamental science and operational requirements, our system is finally capable of predicting solar wind conditions near Earth, especially the arrival times of the co-rotating interaction regions (CIRs) and CMEs. Our test against historical solar wind data from 2007 to 2016 shows that the hit rate (HR) of the high-speed enhancements (HSEs) is 0.60 and the false alarm rate (FAR) is 0.30. The mean error (ME) and the mean absolute error (MAE) of the maximum speed for the same period are −73.9 km s−1 and 101.2 km s−1, respectively. Meanwhile, the ME and MAE of the arrival time of the maximum speed are 0.15 days and 1.27 days, respectively. There are 25 CMEs simulated and the MAE of the arrival time is 18.0 h.

Space Weather Related to Solar Eruptions With the ASO-S Mission

“…For CMEs, both automatic and manual detection tools [29] are used at SEPC [30]). An algorithm using J-maps [31,32] and the Hough transform [33] is adopted to detect and identify CMEs automatically.…”

“…The operational solar wind prediction system [29] in SEPC first calculates the background solar wind on the source surface at 2.5 R ⊙ . Using the PFSS model [37,38] we extrapolate the magnetic field to the source surface from the photospheric magnetic field synoptic map obtained from the Global Oscillation Network Group (GONG; [39]).…”

“…Here we only include those methods which will possibly be used for the ASO-S mission by our team members. The operational solar wind prediction system [29] in SEPC adopt the ice-cream cone model [48] for the geometric fitting of the detected CMEs. It is the simplest model for 3D reconstruction of CMEs.…”

“…The operational solar wind prediction system [29] in SEPC adopted the modified HAF model to propagate CMEs by taking into account the background solar wind, the eruption source information, and the 3D CME parameters. We adopted a deceleration function for the CME speed profile.…”

“…The inward and outward field lines are indicated by blue and green lines. This Figure is adapted from Wang et al[29].…”