The Wang-Sheeley-Arge Model Presented by NOAA/Space Weather Prediction Center and the Office of Naval Research (ONR)

The Wang-Sheeley-Arge Model predicts the background solar wind speed and the interplanetary magnetic field (IMF) polarity at earth, two important parameters required for predicting geomagnetic activity.

Predicted Solar Wind Speed at Earth

Click on plot to see last three rotations

Predicted Interplanetary Magnetic Field (IMF) Polarity at Earth

1- to 7-day Advanced Solar Wind Speed and IMF Polarity Predictions

The plots of 1-day to 7-day advanced solar wind speed and IMF polarity predictions are created using daily updated WSO, SOLIS, and GONG synoptic maps from Wilcox (WSO), NSO/SOLIS(NSO), and National/GONG (GONG) Solar Observatories. Typically, 3-day and 4-day advanced predictions provide the best overall agreement with the observations, because the mean propagation time from the source surface to earth is about 3 to 4 days. 144 2.5^o x 2.5^o cells lie along the ecliptic line of each synoptic map, therefore the solar wind speed/IMF polarity can be predicted with a time resolution of about 1/5 day (i.e., 27.2753/144 = 0.19 days). A 3-day advanced prediction means, in practical terms, that we select those five solar wind speed/IMF polarity values that lie within the time range 3 +/- 0.5 days ahead of the date in which a particular synoptic map was created.

Global Maps of the Sun for Three Different Observatories

Carrington Rotation Start and End Dates

Wang-Sheeley-Arge Model Version 2.2, 2.5 degree resolution