Epochs of phase coherence between El Niño/Southern Oscillation and Indian monsoon

We present a modern method used in nonlinear time series analysis to investigate the relation of two oscillating systems with respect to their phases, independently of their amplitudes. We study the difference of the phase dynamics between El Niño/Southern Oscillation (ENSO) and the Indian Monsoon on inter‐annual time scales. We identify distinct epochs, especially two intervals of phase coherence, 1886–1908 and 1964–1980, corroborating earlier findings from a new point of view. A significance test shows that the coherence is very unlikely to be the result of stochastic fluctuations. We also detect so far unknown periods of coupling which are invisible to linear methods. These findings suggest that the decreasing correlation during the last decades might be a typical epoch of the ENSO/Monsoon system having occurred repeatedly. The high time resolution of the method enables us to present an interpretation of how volcanic radiative forcing could cause the coupling.

[1]  B. Parthasarathy,et al.  Fluctuations in All-India summer monsoon rainfall during 1871–1978 , 1984 .

[2]  E. Rasmusson,et al.  The biennial component of ENSO variability , 1990 .

[3]  Peter J. Webster,et al.  Monsoon and Enso: Selectively Interactive Systems , 1992 .

[4]  J. Hansen,et al.  Stratospheric aerosol optical depths, 1850–1990 , 1993 .

[5]  S. Philander,et al.  Secular Changes of Annual and Interannual Variability in the Tropics during the Past Century , 1995 .

[6]  Kurths,et al.  Phase synchronization of chaotic oscillators. , 1996, Physical review letters.

[7]  P. Webster,et al.  Monsoons: Processes, predictability, and the prospects for prediction , 1998 .

[8]  Balaji Rajagopalan,et al.  Analyses of global sea surface temperature 1856–1991 , 1998 .

[9]  A. Berger,et al.  Volcanic and solar impacts on climate since 1700 , 1999 .

[10]  S. Philander.  A review of tropical ocean–atmosphere interactions , 1999 .

[11]  P. Webster,et al.  Interdecadal changes in the ENSO-monsoon system , 1999 .

[12]  Rajagopalan,et al.  On the weakening relationship between the indian monsoon and ENSO , 1999, Science.

[13]  A. Robock.  Volcanic eruptions and climate , 2000 .

[14]  Alexander Gershunov,et al.  Low-Frequency Modulation of the ENSO-Indian Monsoon Rainfall Relationship: Signal or Noise? , 2001 .

[15]  M. Rosenblum,et al.  Detecting direction of coupling in interacting oscillators. , 2001, Physical review. E, Statistical, nonlinear, and soft matter physics.

[16]  Masato Sugi,et al.  Pacific decadal oscillation and variability of the Indian summer monsoon rainfall , 2003 .

[17]  David A. Robinson,et al.  Land surface conditions over Eurasia and Indian summer monsoon rainfall , 2003 .

[18]  Sulochana Gadgil,et al.  The Indian monsoon and its variability , 2003 .

[19]  J. Kurths,et al.  Three types of transitions to phase synchronization in coupled chaotic oscillators. , 2003, Physical review letters.

[20]  Caspar M. Ammann,et al.  Proxy evidence for an El Niño-like response to volcanic forcing , 2003, Nature.

[21]  Douglas Maraun,et al.  Nonlinear Processes in Geophysics , 2000 .

[22]  Ramesh P. Singh,et al.  Further evidences for the weakening relationship of Indian rainfall and ENSO over India , 2004 .

[23]  Hongxu Zhao,et al.  On the relationship between Tibetan snow cover, the Tibetan plateau monsoon and the Indian summer monsoon , 2004 .

[24]  Mark A. Cane,et al.  The evolution of El Nino, past and future , 2005 .