March 2, 2009 Recent Changes to Solar Cycle Values and Plots March 2, 2009 -- The Solar Cycle 24 Prediction Panel has not issued any updates to their prediction. However, the Space Weather Prediction Center, and the Chair of the Prediction Panel decided to implement what they believe to be an obvious change to the plotted data. The two predictions, of maximum being either a SSN of 90 or a SSN of 140 remain intact. Once the date of solar minimum is known, that is all the information needed to arrive at a prediction curve. The panel prediction of solar minimum in March, 2008 has been eclipsed. Minimum will now occur no earlier than August, 2008. For every month beyond March 2008 that minimum slips, it is necessary to shift the prediction curves by the same amount. SWPC commenced doing so in mid-February and will continue to do so, unless or until the prediction panel sets a new predicted date for the time of solar minimum. ============================================================================== ============================================================================== ISES Solar Cycle Progression and Prediction Displays The initial ISES Solar Cycle 24 Prediction was released in April, 2007. The panel charged with determining the prediction was unable to agree on a single solution and have so far provided two predictions. Those two predictions are available here, along with an average of the two predictions. The average is currently being used as the official prediction. The ISES panel does not consider this to be an adequate solution. To mitigate this, the lower and upper bounds used with the average cover the range of the two predictions issued by the panel. When the panel converges on a single prediction, the files here will be updated to reflect the new prediction. The two predictions issued by the panel can be accessed in the files named Predict_low.txt and Predict_high.txt. The file formats, including the number of lines in the headers,have remained unchanged with this new release. The solar cycle text and graphic files track the Solar Cycle progression. The same data and plots appear in SWPC's "Weekly" publication in Adobe format at URL: http://www.swpc.noaa.gov/weekly/ UPDATE SCHEDULE: The Solar Cycle products are updated once a month and are put on-line the first Tuesday after the new values are available. The latest values are usually available on the 3rd of every month. TERMS AND DEFINITIONS: The official International Sunspot Number (RI) is issued by the Sunspot Index Data Center (SIDC) in Brussels. Data and plots are available from the SIDC web site at http://sidc.oma.be The Space Weather Prediction Center (SWPC) issues a preliminary sunspot number. At http://www.swpc.noaa.gov/ftpmenu/indices.html see Daily Solar Data -- last 30 days Daily Solar Data -- current quarter Solar, Particle, and Geomag. Indices beginning Jan. 1994 -- for older data 10.7cm Radio Flux values are measured in Penticton, B.C. Canada. The values are displayed in solar flux units (1 sfu = 10^-22 W/m^2/Hz). The official Ap index is calculated by GeoForschungsZentrum, in Potsdam, Germany (formerly by Institut fuer Geophysik, Goettingen, Germany). http://www.gfz-potsdam.de/pb2/pb23/GeoMag/niemegk/kp_index/ A preliminary estimate is calculated by the United States Air Force (USAF). These files initially use preliminary values, but they are updated as the final values become available through the National Geophysical Data Center (NGDC). http://www.ngdc.noaa.gov/ The official values are normally available one to two months later. CONTENTS: This directory contains the following tabular lists: a) Predict.txt - Predictions of SIDC sunspot number and 10.7cm radio flux. This table contains an average of the two predictions issued by the ISES prediction panel for solar cycle 24. The panel members do not consider the average to be a true representation of their findings. However, the most equitable solution to providing a robust product for customers necessitates using the average. The high and low bounds that are provided span the range of the predictions issued by the panel. The table runs from the most current prediction through January 2016. Because the predictions are for 13-month running smoothed values, the first entry is always six months behind the issue date. High and low bounds to the forecast are also provided. b) RecentIndices.txt - Recent solar and geomagnetic indices running from January 1991 to the present. The table includes the following: observed SWO and SIDC sunspot numbers, the ratio between the two, 13-month running smoothed SWO and SIDC sunspot numbers, observed and smoothed values of 10.7cm radio flux, and observed and smoothed Ap. The most recent Ap values are always USAF estimates; official values are included as they become available. The August 2008 Sunspot number ratio (RI/SW) was minus 1 (-1). The observed RI number was 0.5 and the SWO number was 0.0 which made the RI/SW ratio a divide by 0. RI and SWO numbers are not calculated in the same way. SWO has a non-zero sunspot number only if there was a numbered active region on the disk. SIDC, the official home for RI sunspot numbers, does not have this same requirement. c) Predict_low.txt - Predictions of SIDC sunspot number and 10.7cm radio flux. This table reflects the view of one half of the ISES prediction panel that solar cycle 24 will be smaller than average. The table runs from the most current prediction through January 2016. Because the predictions are for 13-month running smoothed values, the first entry is always six months behind the issue date. High and low bounds to the forecast are also provided. d) Predict_high.txt - Predictions of SIDC sunspot number and 10.7cm radio flux. This table reflects the view of one half of the ISES prediction panel that solar cycle 24 will be larger than average. The table runs from the most current prediction through January 2016. Because the predictions are for 13-month running smoothed values, the first entry is always six months behind the issue date. High and low bounds to the forecast are also provided. The running smooth calculation takes the most recent 13 months and does a weighted average such that the first month and the last month get 1/2 weight and the other months get weights of 1. Ap(avg)=(0.5*Ap(1) + 1.0*Ap(2) + 1.0*Ap(3) + ... + 1.0*Ap(12) + 0.5*Ap(13))/12.0 The following plots are available: a) sunspot.gif - ISES Solar Cycle Sunspot Number Progression. This plot displays SIDC monthly sunspot numbers, SIDC 13-month running smoothed sunpot numbers, and the most recent forecasts for the low and high predictions. b) f10.gif - ISES Solar Cycle F10.7cm Radio Flux Progression. This plot displays monthly Penticton 10.7 cm Radio Flux values, 13-month running smoothed values, and the most recent forecasts for the low and high predictions. c) Ap.gif - ISES Solar Cycle Ap Progression. This plot displays monthly average Ap values and 13-month running smoothed Ap values. The most recent data are always USAF estimates; offical values are included as they become available. Alternative Solar Cycle Plots are available at: http://solarscience.msfc.nasa.gov/predict.shtml and http://sidc.oma.be/sunspot-index-graphics/sidc_graphics.php http://www.ips.gov.au/Solar/1/6 Please send questions and comments to SWPC.Webmaster@noaa.gov .