What Will Solar Cycle #24 Bring?
While many in the field claimed Solar Cycle #24 would be as strong or stronger then Solar Cycle #23. Many expected Solar Cycle #24 to start earlier as well, this hasn't occurred. Therefore, we are seeing many revised forecasts, lowering the strength of the Solar Cycle #24's relative maximum of sunspot activity. It has been shown that the relative minimum of sunspot activity between Solar Cycle's #23 and #24 is still occurring. (Note the 0.7 sunspot number for March 2009, the lowest value since August 2008)
How does the Relative Minimum Data (Between Solar Cycle #X & #Y) effect the Relative Maximum Data of Solar Cycle #Y ?
Using the monthly sunspot activity dataset, an interesting pattern does show up. Think of the relative minimum between Solar Cycle #X (or #23) and #Y (or #24), the weaker the sunspot activity during that relative minimum has an effect on the relative maximum of Solar Cycle #Y - #24. Therefore, Solar Cycle #Y - #24 will have a weak relative maximum and vice versa is true as well. In later charts, I call the relative minimum sunspot activity between Solar Cycle #X and #Y, Pre-Minimum Weakness Intensity or PMWI. The PMWI actually measures the lack of sunspot activity during a relative minimum on a positive scale. The relative maximum sunspot activity of Solar cycle #Y is called the Post-Maximum Strength or the PMS. The PMS measures the abundance of sunspot activity during a relative maximum on a positive scale. Note that the PMWI is always BEFORE the PMS for data purposes. AKA Preceding (Pre)-PMWI and Ending (Post)-PMS. It can be stated, that as the PMWI increases, the PMS decreases. Therefore, the PMS is generally inversely proportional to the PMWI.
Figure #1 shows the inverse relationship of all PMWI's and corresponding PMS's of all solar cycles since 1749. Notice the R^2 shows a well pronounced relationship for 23 Paired Datasets (23 Solar Cycles).
Figure #2 also shows this inverse relationship, showing little inconsistency and a couple values that deviate (Like SC-#2 and SC-#19). In General, the PMWI increases, as the PMS decreases. The label's at the bottom of Figure #2 represent the solar cycle's relative maximum (SC-#Y). Notice the possibilities for SC-#24, currently the Most Recent PMWI is 83 as of March 2009. The current PMWI is continuing with daily sunspot data zeroing out during the last 20 days as of April 14th, 2009. If this inactivity continues for the Next 9 months, regardless of a slight rise in monthly sunspot numbers to near 20, the PMWI of SC-#24 could easily be 100 or more. Now look at Solar Cycle #5, this was the beginning of the Dalton Minimum (SC-#5 to SC-#7). During SC-#5 the PMWI broke 100. The same goes for the minimum in the late 1800's and early 1900's (SC-#12 to SC-#15). The Solar Cycle #12 PMWI was a value of 106, over 100. When a PMWI of a Solar Cycle reaches the 100 > X Barrier, It is an indication that a prolonged Solar lull/minimum period is going to last for at least 2 eleven-year Solar Cycles or more (hence Dalton or Late 1800's/Early 1900's period).
Figure #3 shows the PMS/PMWI data in chart form chronologically. The Pre-Minimum Period is determined by the clustering of monthly sunspot activity values of 20 or below. For example, the Pre-Minimum Period for Solar Cycle #10 is from January 1854 (Earliest a monthly value of 20 or lower is found, Start) to August 1857 (Latest a monthly value of 20 or lower is found, End). The data from these Pre-Minimum Periods then can be used to calculate the PMWI for each Solar Cycle. (Goto: "How is the PMWI and PMS calculated?" for this information)
On the Other Hand, the Post-Maximum Period is determined by the clustering of monthly sunspot activity values of 50 or above. Using example, the Post-Maximum Period for Solar Cycle #10 is from March 1858 (Earliest a monthly value of 50 or above is found, Start) to November 1864 (Latest a monthly value of 50 or above is found, End). The data from these Post-Maximum Periods then can be used to calculate the PMS for each Solar Cycle. (Goto: "How is the PMWI and PMS calculated?" for this information)
In a few cases the Pre-Minimum Period and the Post-Maximum Period can overlap. This occurs where the monthly sunspot numbers are very-volatile in nature, and where the Pre-Minimum & Post-Maximum Periods coincide via clustering of values. It only occurs 3 times within the monthly sunspot number data. Most of the time between the Pre-Minimum & Post-Maximum Periods you get monthly sunspot numbers between 20 and 50.
Again, notice when a PMWI value hits 100 or more that is a sign that we are headed for a long-term solar minimum. As of March 2009, the PMWI value of SC-#24 is 83, this is preliminary. This PMWI value will rise, most likely to 100 or more I believe.
Figure #4 shows the PMS/PMWI data in form chronologically via bar graph and per Solar Cycle. Above the bar graph, is a line graph of monthly sunspot numbers. This shows how the data is connected. In 1816 there was a tale of a year without a summer. It snowed in the Eastern United States and Europe in the Summer of 1816. Right before 1816, the PMWI value was 206 (The Highest PMWI ever) and the PMS value was 10 (The Lowest PMS ever). The period between SC-#5 and SC-#6 had the lowest relative minimum of sunspot activity on record. SC-#6's Maximum was also the quietest on record.
How is the PMWI and PMS calculated?
The PMWI is calculated simply by a points system. The PMWI can only be calculated within a Pre-Minimum Period as described above. Let's use the PMWI for Solar Cycle #10 an example. Remember, this is the relative minimum sunspot activity between Solar Cycle #9 and #10, Pre-Minimum Weakness Intensity or PMWI of Solar Cycle #10.
The formula says all months with a sunspot number of 20 or below within the Pre-Minimum Period are included in the formula. Note that Pre-Minimum Periods can vary in terms of time periods or number of months. Each of the 44 months within Pre-Minimum Period of Solar Cycle #10 gets a Point Rating. Simply add up all the monthly point ratings of each month within the Pre-Minimum Period of Solar Cycle #10. The PMWI of SC-#10 comes out to be 71.
The PMS is calculated simply by a points system. The PMS can only be calculated within a Post-Maximum Period as described above. Let's use the PMS for Solar Cycle #10 an example. Remember, the relative maximum sunspot activity of Solar cycle #Y is called the Post-Maximum Strength or PMS of Solar Cycle #10.
The formula says all months with a sunspot number of 50 or above within the Post-Maximum Period are included in the formula. Note that Post-Maximum Periods can vary in terms of time periods or number of months. Each of the 81 months within Post-Maximum Period of Solar Cycle #10 gets a Point Rating. Simply add up all the monthly point ratings of each month within the Post-Maximum Period of Solar Cycle #10. The PMS of SC-#10 comes out to be 69.
All the information is calculated in Excel Spreadsheet in Figure #5. The Min Total is the Monthly Point Rate of the Pre-Minimum Period. The Max Total is the Monthly Point Rate of the Post-Maximum Period. The blue highlighted columns are all the months and values in the PMWI. The red highlighted columns are all the months and values in the PMS. I also excluded the data from October 1906 and March 1922 because it was anomalous data that didn't best represent a PMS or PMWI value. Exclusion of Data: