SST phases in the open-ocean and margins of the tropical Pacific; implication on tropical climate dynamics
L.-J. Shiau1, S. C. Clemens2, M.-T. Chen1, M. Yamamoto3, and Y. Yokoyama41Institute of Applied Geosciences, National Taiwan Ocean University, Keelung 20224, Taiwan 2Department of Geological Sciences, Brown University, Providence 02912, RI, USA 3Faculty of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan 4Atmosphere and Ocean Research Institute and Department of Earth and Planetary Sciences, University of Tokyo, Tokyo 113-0033, Japan
Received: 28 Feb 2014 – Accepted for review: 14 Mar 2014 – Discussion started: 28 Apr 2014
Abstract. The tropical Pacific exerts a major effect on the global climate system and might have driven large extra-tropical climate change. We present a 320 kyr high resolution UK'37-sea surface temperature (SST) record from core MD052928 (11°17.26' S, 148°51.60' E, water depth 2250 m) located off southeastern Papua New Guinea (PNG), in the western tropical Pacific. The age model of the core is based on AMS 14C dating of planktic foraminifers and correlation of benthic to the LR04 stack. The UK'37-SST ranges from 26.5 to 29 °C, showing glacial–interglacial and millennial variations. We assess the phase of the MD052928 UK'37-SST as part of a synthesis of five other SST records from the tropical Pacific at the precession, obliquity, and eccentricity bands. The SST records can be separated into two groups when considering SST phase relative to changes in orbital forcing, ice volume and greenhouse gases (GHGs). SST maxima at open-ocean sites within primary equatorial current systems occur between obliquity maxima and methane (CH4) maxima but early relative to ice volume minima and CO2 maxima at the obliquity band. In contrast, SST maxima at continental margin sites change are in phase with ice minima and CO2 maxima, likely influenced by the slow response of continental ice sheets and GHGs. At the precession band, the early group located on the Warm Pool area indicates a direct influenced by the local insolation, and with the similar phase progress as the obliquity band. These results indicate that the decreased high-low latitudes insolation gradient and increasing low latitude local insolation resulting in tropical Pacific SST rise. Higher SST would supply more moisture resulting in increased CH4 in the tropical wetlands. This promotes increasing CO2 and deglaciation leading to increase continental and continental margin surface temperatures.
Shiau, L.-J., Clemens, S. C., Chen, M.-T., Yamamoto, M., and Yokoyama, Y.: SST phases in the open-ocean and margins of the tropical Pacific; implication on tropical climate dynamics, Clim. Past Discuss., 10, 1857-1899, doi:10.5194/cpd-10-1857-2014, 2014.