1State Key Laboratory of Mar. Geol., Tongji University, Shanghai 200092, China
2Department of Meteorology, University of Hawaii at Manoa, Honolulu, HI 96825, USA
3Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
4Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA
5CAS/NCAR, National Center for Atmospheric Research, 3090 Center Green Dr., Boulder, CO 80301, USA
6Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China
7PAGES International Project Office, Zähringerstrasse 25, 3012 Bern, Switzerland
8Laboratory Climate, Ocean and Atmospheric Studies, School of Physics, Peking University, Beijing 100871, China
9Center for Climatic Research, University of Wisconsin Madison, Madison, WI 53706, USA
Received: 21 Apr 2014 – Discussion started: 15 May 2014
Abstract. Monsoon has earned increasing attention from the climate community since the last century, yet only recently have regional monsoons been recognized as a global system. It remains a debated issue, however, as to what extent and at which timescales the global monsoon can be viewed as a major mode of climate variability. For this purpose, a PAGES (Past Global Changes) working group (WG) was set up to investigate the concept of the global monsoon and its future research directions. The WG's synthesis is presented here. On the basis of observation and proxy data, the WG found that the regional monsoons can vary coherently, although not perfectly, at various timescales, varying between interannual, interdecadal, centennial, millennial, orbital and tectonic timescales, conforming to the global monsoon concept across timescales. Within the global monsoon system, each subsystem has its own features, depending on its geographic and topographic conditions. Discrimination between global and regional components in the monsoon system is a key to revealing the driving factors in monsoon variations; hence, the global monsoon concept helps to enhance our understanding and to improve future projections of the regional monsoons. This paper starts with a historical review of the global monsoon concept in both modern and paleo-climatology, and an assessment of monsoon proxies used in regional and global scales. The main body of the paper is devoted to a summary of observation data at various timescales, providing evidence of the coherent global monsoon system. The paper concludes with a projection of future monsoon shifts in a warming world. The synthesis will be followed by a companion paper addressing driving mechanisms and outstanding issues in global monsoon studies.
Revised: 19 Sep 2014 – Accepted: 30 Sep 2014 – Published: 21 Nov 2014
Wang, P. X., Wang, B., Cheng, H., Fasullo, J., Guo, Z. T., Kiefer, T., and Liu, Z. Y.: The global monsoon across timescales: coherent variability of regional monsoons, Clim. Past, 10, 2007-2052, doi:10.5194/cp-10-2007-2014, 2014.