Solar Cycle 22, which began in September 1986, continues to rise at a rate that rivals or exceeds that of all sunspot cycles in the record of direct sunspot observations. As measured by smoothed sunspot numbers and 10.7-cm radio flux values, Cycle 22 remains ahead of all past cycles in the modern record except Cycle 19, which peaked during the late 1950s (see Figure 1). By other measures, such as the number of X ray flares or solar proton events, this cycle is running up to 30% higher than at the corresponding point in all previous cycles.
In our previous report (“Solar and Geomagnetic Activity During Cycle 21 and Implications for Cycle 22,” Eos, 69, 962, 1988) we presented early information on Cycle 22 and discussed some possible solar-terrestrial effects of solar activity. Figure 1 updates that information to the present in sunspot number and 10.7-cm radio flux values.