A novel method for detecting abrupt dynamic change based on the changing Hurst exponent of spatial images
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- 作者：Wen-Ping He ; Qun-Qun Liu ; Bin Gu ; Shan-Shan Zhao
- 关键词：Abrupt change detection ; Hurst exponent ; Two ; dimensional detrended fluctuation analysis ; Spatial image
- 刊名：Climate Dynamics
- 出版年：2016
- 出版时间：October 2016
- 年：2016
- 卷：47
- 期：7-8
- 页码：2561-2571
- 全文大小：3,722 KB
- 刊物类别：Earth and Environmental Science
- 刊物主题：Earth sciences
Geophysics and Geodesy
Meteorology and Climatology
Oceanography - 出版者：Springer Berlin / Heidelberg
- ISSN：1432-0894
- 卷排序：47
文摘
The climate system is a classical spatiotemporal evolutionary dynamic system with spatiotemporal correlation characteristics. Based on this, two-dimensional detrended fluctuation analysis (TD-DFA) is used to estimate the Hurst exponent of two-dimensional images. Then, we monitored the change of the Hurst exponent of the images to identify an abrupt dynamic change. We tested the performance of this method with a coupled spatiotemporal dynamic model and found that it works well. The changes in the Hurst exponents of the spatial images are stable when there is no dynamic change in the system, but there will be a clear non-stationary change of the Hurst exponents; for example, the abrupt mean values change if the dynamics of the system change. Thus, the TD-DFA method is suitable for detecting an abrupt dynamic change from natural and artificial images. The spatial images of the NCEP reanalysis of the daily average temperature exhibited fractality. Based on this, we found three non-stationary changes in the Hurst exponents for the NCEP reanalysis of the daily average temperature or for the annual average temperature in the region (60°S–60°N). It can be concluded that the climate system may have incurred three dynamic changes since 1961 on decadal timescales, i.e., in approximately the mid-1970s, the mid-1980s, and between the late 1990s and the early 2000s.