2005 Volume 114 Issue 3 Pages 460-484
Research on factors of climate variations on a seasonal to multi-decadal timescale is surveyed. However, it is difficult to fully cover wide-ranging research on climate systems including the latest results. This paper focuses on phenomena such as QBO that interact with the other factors. Oceans, which have a close relationship with climate change, are considered. Although there is overlapping with dissertations in another chapter, the main contents are as follows 1) ENSO is a quasi-periodic air-sea interaction, which has been studied closely. If evolvement of ENSO is predicted, it will make seasonal weather forecasts more precise. 2) The effects of stratospheric QBO on climate systems in the troposphere might have been exercised as grave cool damage that occurs in summers when QBO was in the W-phase, and some correlations have been found. QBO probably holds a significant key explaining climate variations. Therefore, elucidation of the QBO mechanism that influences the troposphere can be expected. 3) The relationship between solar activities and climate remains obscure. However, some influences of solar activities on the tropospheric circulation have been felt through sea surface temperature or interaction with stratospheric QBO. 4) In the air-sea interaction the ocean responds to solar radiation more slowly than the atmosphere, so the ocean seems to play a dominant role in long-lived teleconnections such as PDO. In addition, regime shifts of oceans sometimes have major effects on climate. We cannot discuss climate change without referring to oceans. 5) Global warming is in progress. As a result, shifts in general circulation might lead to abnormal weather, which means increased danger of frequent developments of the Okhotsk high, which is responsible for cool summer damage. 6) It is important to evaluate which factors contribute greatly to climate change. Understanding the mechanisms of weather fluctuations ranging from a few months to several years is a pressing matter to prevent recurrence of meteorological disasters.
