Sunspot, numbers from

Figure 2 Sunspot numbers from 1955 to present depicting the recent solar cycle.

Recently, a U.S.S.R.-Czechoslovokian research group have reported 14C data for dated wine samples from the Caucasus Mountains [27]. Their results are in fairly close agreement with our results for the time of overlapping data (figure 5). If the anomalous data for A.D. 1943 are omitted, the fifth order polynomial fit to the data yields a 5 per mil peak to trough amplitude with a phase lag of 4 years behind sunspot numbers. The amplitude... 

Figure 14.54, for example, shows the annual average number of sunspots from 1880 to the present, which clearly shows this cycle (Cliver et al., 1998). Both the sunspot number and the aa geomagnetic index have been used as proxies for the solar cycle. For the relatively short time period covered by available instrumental temperature records, both the sunspot number and the aa geomagnetic index are correlated to surface temperature (e.g., see Cliver et al., 1998 and Wilson, 1998). 

Bob takes the magnet from Mr. Plex s claws. The Sun s magnetic field extends throughout the solar system. It s quite complicated because of the Sun s rotation and the convection of electrically charged particles in the Sun s hot gases. The magnetic field reverses every 11 years, right after the time when the sunspot number peaks. ... 

Figure 10 Comparison of the solar irradiance with the sunspot numbers for the last two Schwabe cycles. The irradiance record is a compilation of data from different satellites. During penods of high solar activity there are more sunspots darkening a small part of the solar disk (visible in the negative exc ions of the radiance). However, the brightness of ffe Sun is increased at the same time, overcompensatmg the darkening effect of the sunspots.

Sunspot number— An international estimate of the total level of sunspot activity on the side of the sun facing the earth, tabulated at the Zurich Observatory. Observations from around the world are sent to Zurich, where they are converted into an official sunspot number. Since the sun rotates, the sunspot number changes daily. 

The flux in the Extreme Ultraviolet (EUV) portion (10-100 nm) of the solar spectrum (see Figure 4.8a) directly affects the chemistry and dynamics of the thermosphere. Its value, and hence the ionization rate in the upper atmosphere, varies substantially with solar activity. Richards et al. (1994) have developed a model that provides the extra-terrestrial solar actinic flux from 5 to 105 nm as a function of a solar proxy P which is the average between the instantaneous radiowave flux F10.7 emitted by the Sun at 10.7 cm and its average value Fio.7,4 over 81 days. The 10.7 cm flux is routinely monitored and reported in units of 10-22 W m 2Hz 1 its value ranges typically from 70 (solar minimum) to 200 (solar maximum), and is highly correlated with other indicators of solar activity (e.g., sunspot number). 

Figure 5. Comparison between the daily sunspot number of July 2000 and July 2001 (results are elaborated from the database of National Oceanic and AtmosphericAdministration, fip //ftp.ngdc.noaa.gov/STP/SOLAR DATAJ...

FIGURE 14.54 Annual average number of sunspots from 1880 to 2000, showing the 11-year cycle (adapted from diver et al., 1998). 

The period from 1654 to 1714 when it was believed that there were no sunspots. It is now thought that there were some sunspots during that time but less than the numbers counted after 1800. mean sea level... 

However, the early sun was quite different from the sun we know. Its luminosity was only about 70% of its present value. It rotated much faster. SteUar rotation is an important parameter to trigger stellar activity. The present day sun shows an activity cycle with a period of about 11 years. The number of sunspots varies but also the number of flare occurrence (these are energetic outbursts caused by a reconnection... 

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