Global temperature as a regulator of climate predictability

✍ Scribed by A.A. Tsonis; J.B. Elsner

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 536 KB
• Volume: 108
• Category: Article
• ISSN: 0167-2789
• DOI: 10.1016/s0167-2789(97)82013-1

✦ Synopsis

The possibility of changes in the dynamical behavior of our climate system as the global temperature fluctuates is investigated by considering the large climate variation of the Pacific ocean-atmosphere system associated with Southern Oscillation Index (SOI) and modem methods of time series analysis. First the nonlinear structure of SO1 is probed by estimating local Lyapunov exponents. We obtain the sum of all positive Lyapunov exponents (Kolmogorov entropy) as a function of time for the period between June 1882 and May 1987. We then demonstrate that this time series and global temperature records are coherent over the Nyquist frequency band from 0.0 to 0.25 cycles/year thus establishing linear relationship between many of their oscillatory components. Since the inverse of the Kolmogorov entropy is a measure of predictability this result indicates that global temperature may affect predictability with higher temperatures corresponding to lower predictability. We discuss how this result may eventually lead to the development of strategies for improved long-term predictions.