The area of sunspot groups is expressed in “millionths of a solar hemisphere” (MH), with 1000MH corresponding to 3.043,7 million square kilometers. Both the Boulder and the International numbers are calculated from the same basic formula, but they incorporate data from different observatories. ). The sunspot plotter is easy to use. The relative sunspot number is defined as R = K (10g + s), where g is the number of sunspot groups and s is the total number of distinct spots. Yearly mean and 13-month smoothed monthly sunspot number since 1700.

Let™s go to the next level and compare smoothed solar flux to smoothed sunspot number (smoothed solar flux is calculated in the same way as the smoothed sunspot number). without to forget the Effective Sunspot Number or SSNe calculated from real-time foF2 observations. The scale factor K (usually less than unity) depends on the observer and is intended to effect the conversion to the scale originated by Wolf. Some sunspot facts: • Sunspots are dark, cooler areas on the Sun’ s surface that indicate areas of strong magnetic activity • They appear dark only because they are not as hot or bright as the area surrounding them (4,000 degrees C. vs. 6,000 degrees C.) • Sunspots … These plots provide a look at the global behavior of the ionospheric F2 layer over the past week as measured by the NWRA effective sunspot number (SSNe) calculated from current observations. How do you determine the size of a sunspot region?

- There is a sunspot number derived from the 10.7 cm solar radio flux called SSNf (the one used in correlation with SFI). Sunspot Number Daily, monthly and 13-month smoothed sunspot numbers for the past 13 years, and 12-month ahead predictions. Since the middle of the 18th century sufficient data has been collected to produce systematic records of sunspots.

There are various measurements that can be made by the solar observer. The "sunspot number" is then given by the sum of the number of individual sunspots and ten times the number of groups. North and South hemispheric sunspot numbers (13-month smoothed values) over the last 6 cycles. The values in the smoothed 10.7 cm solar flux table are derived from daily 10.7 cm solar flux values adjusted to 1 Astronomical Unit (A.U. Today, the "sunspot number" is calculated by first counting the number of sunspot groups and then the number of individual sunspots. This is done for July 1999 through June 2001. The upper panel shows the SSNe variation, the third panel provides a goodness-of-fit metric (described below), and the lower panel gives the total number of foF2 observations in each SSNe calculation. The new (Version 2.0) sunspot numbers are unweighted sunspot number counts. This means that a sunspot group which has an area coverage of 1870MH covers 0.187% of the earth-facing solar surface. - There is a sunspot number derived from fitting an ionospheric model to ionospheric measurements. The Bureau of Meteorology SWS solar cycle prediction is now based on the Version 2.0 values.

Figure 1 shows the estimate of sunspots since 1600 prepared by Hoyt and Schatten. The average value from the observations made during each month is then calculated - it is these monthly averages that are shown in the plot. For example, select your birth date from the pull-down menus and the plotter instantly shifts to the day you were born: The red curve traces monthly-averaged sunspot numbers tabulated by the Solar Influences Data Center in Belgium. The sunspot number is calculated by first counting the number of sunspot groups and then the number of individual sunspots. Sunspots vary in their size and simply counting the number of spots is a bit inconsistent. Monthly and 13-month smoothed sunspot numbers over the last 6 cycles. Two things are very obvious from this chart. The one shown below is the sunspot number R. This is calculated from the number of groups and the number spots seen each day. The Boulder number is usually about 25% higher than the other official index, the "International Sunspot Number," published daily by the Sunspot Index Data Center in Belgium.