# Presentation: 569598

## Solar Cycle 24Prediction Panel Update

- D.A. Biesecker
- NOAA/NWS/SWPC
- And the Cycle 24 Prediction Panel

## Outline

- The April 2007 Solar Cycle Prediction
- Arguments for and against
- Where is the Sun now?
- What’s the latest from the panel?

## The Background

- Charged with determining the official prediction for Solar Cycle 24 for NOAA, NASA, and the International Space Environment Service (ISES)
- Time and intensity of solar cycle 24
- Sunspot number
- F10.7
- Panel chaired by NOAA, funded by NASA
- Previous panels met in 1989 and 1996
- International membership
- The panel has 12 voting members
- Only 11 voted on these predictions

## The Panel

| Panelist | Affiliation | Panelist | Affiliation | Panelist | Affiliation |
| --- | --- | --- | --- | --- | --- |
| D. Biesecker | NOAA, Chair | M. Dikpati | NCAR | K. Dowdy | USAF |
| D. Hathaway | NASA | T. Hoeksema | Stanford U. | E. Kihn | NOAA |
| H. Lundstedt | Swedish Inst. of Space Sci. | D. Pesnell | NASA | M. Rast | U. Colorado |
| L. Svalgaard | ETK Inc. | R. Thompson | IPS Australia | R. Van der Linden | Royal Obs. Of Belgium |
| J. Kunches | NOAA,
ex-officio | O.C. St. Cyr | NASA,
ex-officio |  |  |

## Predicting Cycle 24

- Climatology and Recent Climatology
- Spectral and Neural Network
- Precursor
- Physics Based

- The Third Official Prediction Panel

- From Pesnell

## April 2007 Panel Prediction

- Solar Minimum will be in March, 2008
- Cycle 24 will be small
- Ri = 90
- August, 2012
- 	or
- Cycle 24 will be large
- Ri = 140
- October, 2011
- The panel is split

## Why the Split?

- The Sun recycles its magnetic fields in 1 solar cycle
- The Sun recycles its magnetic fields in 2-3 solar cycles

## What would change things?

- Would small cycle proponents concede?
- What they said one year ago
- If the polar field strength increases  increased Cycle 24
- If geomagnetic activity increases  increased Cycle 24

## What would change things?

- Would big cycle proponents concede?
- What they said one year ago
- A clear demonstration of how polar fields can produce sunspots at latitudes below 30o just a few years later.
- The already historically weak meridional flow may weaken by yet another factor of two and produce a small cycle 24.
- No evidence of new cycle spots by mid-2008

## What has the Sun done?

- We’re seeing new cycle spots
- Old Cycle and New cycle
- 	spots coexist
- Old cycle at low latitudes
- New cycle at high latitudes

## What has the Sun done?

- Have we reached minimum yet?

## What will happen?

- Did the panel get it wrong?  Was minimum in September 2007?
- The panel error bar was 6 months, which allows Sep 07

| Jan
2007 | Feb 2007 | Mar 2007 | Apr 2007 | May 2007 | Jun 2007 | Jul 2007 | Aug 2007 | Sep 2007 | Oct 2007 | Nov 2007 | Dec 2007 | Jan 2008 | Feb 2008 | Mar 2008 | Apr 2008 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 16.8 | 10.7 | 4.5 | 3.4 | 11.7 | 12.1 | 9.7 | 6.0 | 2.4 | 0.9 | 1.7 | 10.1 | 3.4 | 2.1 | 9.3 | 2.9 |
| 11.9 | 11.5 | 10.7 | 9.9 | 8.7 | 7.7 | 7.0 | 6.0 | 5.9 | 6.0 |  |  |  |  |  |  |

## T. Woods SORCE 2008

## Summary

- Solar Minimum will be in March, 2008
- Re-affirmed by panel in March, 2008
- Cycle 24 will be small
- Ri = 90
- August, 2012
- 	or
- Cycle 24 will be large
- Ri = 140
- October, 2011
- The panel is still split

## Predicting Cycle 21

- 1979 Boulder, CO – STP  Workshop
- 	18 Statistical Predictions – solid bars
- 	12 Precursor Predictions - shaded bars
- 	8 Other methods - unfilled

- Ri = 164

## Predicting Cycle 22

- 1984 Meudon – STP Workshop
- “At the outset, it was agreed that there have not been any startling new developments in prediction techniques over the intervening five years.”
- 	13 Statistical Methods	18 Precursor Methods
- 	13 Spectral Methods		2 Planetary Influences

- Kunches 1992

## The First ‘Official’ Prediction

- Consensus Estimate ≈ 200
- Clearly based on precursor methods and on
- 	the observed rise behavior of Cycle 22

## Oops, we better reconsider

- Concern for HST re-entry prompted an
- 	April 1990 update to the 1989 official prediction
- Minority opinion: we are past maximum
- Consensus opinion: SSN ≈ 170

## Predicting Cycle 23

- The Second Official Prediction

| Technique | Prediction |
| --- | --- |
| Even/Odd Behavior | 200 ± 35 |
| Precursor | 160 ± 20 |
| Spectral | 155 ± 25 |
| Recent Climatology | 155 ± 30 |
| Neural Networks | 140 ± 30 |
| Climatology | 115 ± 40 |
| Consensus | 160 ± 30 |

- The scientific community should be encouraged to develop a
- fundamental understanding of the solar cycle that would provide
- a physical – rather than empirical – basis for prediction methods.

## Flux Transport Dynamo

- Slowing of meridional flow gives smaller prediction
- Smaller cycle begins later, peaks later

***(Dikpati, de Toma & Gilman, GRL 2006 )***

## Hathaway, Wilson and Reichman (1999)

## D. Hathaway SORCE 2008

## D. Hathaway SORCE 2008