Stochastic climate changes caused by white noise annual updating
Published by Institute of Physics, London , 1992).
Stochastic climate changes caused by white noise annual updating |
||||||||
| According to observations the annual updating of the climate system is white noise, i.e. the annual variance is near independent of the length of the period. Autoregressive models are required where the updating in time is white noise. In Fig.2 and 3 is given an example of. an autoregressive process. | ||||||||
|
||||||||
| Fig.2 Reconstructed record of the annual average temperatures for the northern hemisphere for the last four centuries. The figure shows the deviations from the record mean in Co. The stochastic annual updating is evident. Autoregressive models are required where the updating in time has a stochastic component. The observed annual updating is white noise. | ||||||||
|
||||||||
| Fig.3 The necessary stochastic terms in an autoregressive model of order 4, AR(4), to produce the temperature record in Fig.2.. (After J. Frøyland: Introduction to Chaos and Coherence. Published by Institute of Physics, London , 1992). |
||||||||
| The variance, (a quadratic measure of variability), given in the Fig.3 is white noise. Accordingly the climate system is continuously driven by the white noise input to an ever- increasing variance or chaos on greater time scales. This is also in accordance with the fundamentals of the modern statistical mechanics. The white noise annual updating is capable of explaining the given stochastic climate changes on greater time scales. | ||||||||
| since Sept. 23rd 2001 | ||||||||