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The Wang-Sheeley-Arge Model

Presented by NOAA/Space Weather Prediction Center and the Office of Naval Research (ONR)

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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

3 Day Advanced Predictions
 of Solar Wind Speed

Click on plot to see last three rotations

Predicted Interplanetary Magnetic Field (IMF) Polarity at Earth

3 Day Advanced Predictions of IMF

Click on plot to see last three rotations



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

Plot
Advanced Predictions
Solar Wind Speed
1-day
2-day
3-day
4-day
5-day
6-day
7-day
IMF Polarity
1-day
2-day
3-day
4-day
5-day
6-day
7-day
IMF Polarity, with 2.5
degrees expansion factors
1-day
2-day
3-day
4-day
5-day
6-day
7-day

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 2.5o x 2.5o 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

Plot
Wilcox Solar Observatory (WSO)
Carr Rot.: Carr Long.*
National Solar Observatory NSO/(GONG)
Carr Rot.: Carr Long.*
National Solar Observatory (NSO)/SOLIS
Carr Rot.: Carr Long.*
Photospheric Field
Derived Coronal Holes
Coronal Field
(R=5Rs)
Solar Wind Speed
All Four Plots

Shows two most recent daily updated maps and last three Carrington Rotations.

* Carrington Rotation Number : Carrington Longitude


Carrington Rotation Start and End Dates

Carrington Rotation Start Date End Date
2190 Apr 29, 2017 May 26, 2017
2189 Apr 2, 2017 Apr 29, 2017
2188 Mar 6, 2017 Apr 2, 2017
2187 Feb 6, 2017 Mar 6, 2017
2186 Jan 10, 2017 Feb 6, 2017
2185 Dec 14, 2016 Jan 10, 2017

 

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

For questions, suggestions, or requests contact Leslie Mayer at NOAA/SWPC. (leslie.mayer@noaa.gov)

Visually impaired users may contact SWPC for assistance.

April 14, 2010 Disclaimer, Contact SWPC


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