Abstract
The present study conducted investigations using modern methods of time series analysis to clarify how the increase of the atmospheric carbon dioxide is related to the rise in the air temperature. The interrelationship of the global air temperature to the solar activity also was investigated through correlation analysis using time series datasets of them. The results of spectral analysis showed that the variations of the air temperature and atmospheric carbon dioxide have an obvious one-year cycle (seasonal cycle), and that the spectral intensity of the one-year cycle in the air temperature is greater in the polar regions than in low latitudes, while that in the atmospheric carbon dioxide tends to be lower in southward regions. Through coherence analysis, it was found that there are different tendencies between short-term and long-term fluctuations in the interrelationship of the air temperature to the atmospheric carbon dioxide. The long-term fluctuations in the atmospheric carbon dioxide tend to be accompanied by those in the air temperature, and vice versa in the short-term fluctuations.
