climate time scale

Long daily surface air temperature series from 24 European and Asian stations are analyzed, among them the Central England temperature dataset (1772 – 2005). The mean seasonal cycle in each series is removed and correlations between the consecutive increments of various increment intervals for the anomaly series are calculated. The sample correlations appear to behave similarly for all series. A positive coefficient between the short-term (daily etc) increments rapidly changes to the negative side while the increment interval increases. The value of the coefficient saturates at the level-0.5 and stays at that level for long range of intervals from 20 to 2000 days. The feature is a testimony to the regulating role of (cumulative) negative feedback in the climate system during the last two centuries. 1.

Abstract. The growth rate of the second moment for the time series ’ increment as a function of the increment range can be used for estimating the sign of feedback of the underlying physical system. The influence of the periodic nature of the time series to the growth rate of its structure function is considered. The approach is used to describe the variability of the time series of the global average outgoing long wave radiation (OLR). It is shown that the series ’ annual cycle plays a crucial role in preventing the growth of the variance of the time series ’ increments and leads to its nearly stationary long-range behaviour. The analysis of the OLR time series indicates that a negative feedback should dominate in the earth climate system. The example is believed to be useful for better understanding of the influence of the increasing concentration of CO2 in the Earth’s atmosphere. Key words: Earth climate system, feedback sign, time series analysis.