Fig. 1. Ring width series around the 330 BC event.

Fig. 2. Tree-ring indices around the 330 BC event. Another possible event 419 BC (volcano eruption?)

Fig. 3. Tree-ring index, sample KOM6131.

Fig. 4. Tree-ring index, sample KOM6132 (a pair with KOM6131 on the same cross-section.

Fig. 5. Tree-ring index, sample KOM6717.

Fig. 6. Tree-ring index, sample KOM6724.

Fig. 7. Tree-ring index, sample KOM6742.

Fig. 8. Tree-ring index, sample KOM6532.

Fig. 9. Tree-ring index, sample KOM6724.

Fig. 9. Tree-ring index, sample KOM6724.

We still know quite a little about solar activity. The further investigation has progressed the more have come evident that the Earth is a “child” of the Sun. Sunspot number is connected to the intensity of solar energy production. The about 11-year cycle of sunspots is caused by variation in solar activity. One of the key issues in climate change research today is, how the variations in the Sun's energy output influence Earth climate. Researchers have different views on the matter. The observed 84─95-yr cycle in the Finnish timberline chronology has an interesting connection to the 70─100-yr Gleissberg cycle. If the connection is real, it allows climate forecasting based on tree-rings! We have prepared some tentative climate forecasts. They are based on the cycles of 84─95 years and about 1000 years. Exciting to see in the coming years, whether forecasting based sun and tree-ring cyclicity really works!

SOLAR ACTIVITY

© Mauri Timonen: telescope, Moon, Saturn, Jupiter + the Galilean 4 moons , northern lights and the Sun 1975. © John Laborde : Comet West 9.3.1975

Why is the climate of Finnish Lapland so average? The main reason is a phenomenon called the North Atlantic Oscillation (NAO) that varies periodically causing exceptional weather in Europe and Northern Africa. Active phase of NAO (high index) appears in Finland, particularly in wintertime, as warm-winded but sometimes also as stormy westerlies. Summertime is different: the same climatic pattern causes moist-cool weather pattern.

The Gulf Stream, as a part of the Thermohaline Circulation System (TCS), brings warm water to Northern Europe. When NAO is in its high phase, moist air is distributed by the westerlies to Finland. NAO was exceptionally active in the 1990s, which raised the mean temperature of the winter months by a couple of degrees. Moisture accumulated at the same time as extra snow so that there were in Finnish Käsivarsi even three times, and in other locations of Finnish Lapland twice as much as normally. Since then, NAO has subsided in the 2000s.

Sorce of climate data: CRU

Fig. 10. FFT-11 point smoothed tree-ring index. Some possible volcano events that possibly appear in the tree-rings of Finnish timberline pine: SANTORINI Greece 1640 ± 12 BC, PELÉE West Indies 440 BC (?), ATACAZO Ecuador C 320 ± 16 BC, RABAUL New Britain C 540 ± 100 AD and HUAYNAPUTINA Perú 1600 AD (Source: www_volcano_si_edu_world_largeeruptions_cfm.pdf. See more: http://lustiag.pp.fi/climate2050.pdf, slides 53 and 54.