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The Wang-Sheeley Model

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

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The Wang-Sheeley 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

4 Day Advanced Predictions
 of Solar Wind Speed

Click on plot to see last three rotations

Predicted Interplanetary Magnetic Field (IMF) Polarity at Earth

4 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, MWO, and NSO synoptic maps from Wilcox (WSO), Mount Wilson (MWO), and National/Kitt Peak (NSO) 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. 72 5o x 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 1/3 day (i.e., 27.2753/72 = 0.38 days). A 4-day advanced prediction means, in practical terms, that we select those two or three solar wind speed/IMF polarity values that lie within the time range 4 +/- 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) Kitt Peak
Carr Rot.: Carr Long.*
Mt Wilson Solar Observatory (MWO)
Carr Rot.: Carr Long.*
Photospheric Field
Derived Coronal Holes
Source Surface 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
2023 Nov 8, 2004 Dec 5, 2004
2022 Oct 12, 2004 Nov 8, 2004
2021 Sep 14, 2004 Oct 12, 2004
2020 Aug 18, 2004 Sep 14, 2004
2019 Jul 22, 2004 Aug 18, 2004
2018 Jun 25, 2004 Jul 22, 2004

 

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

Visually impaired users may contact SEC for assistance.

June 23, 2003 Disclaimer, Contact SEC


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