Validating the Pacific Centennial Oscillation: Integrating models and paleo-data
Improving climate predictability requires long, continuous records of major climate indicators (temperature, precipitation etc.) across a large geographical area. Unfortunately, in most parts of the world, but particularly in Southeast Asia, such records are short and geographically sparse. This leaves a gaping hole in our ability to predict and understand climate variability in the most densely populated region in the world. Never has this been more evident than in the last several months in Singapore, Sumatra and Malaysia. As a large El Nino set in, the annual burning of the fields began in Kalimantan and Borneo. With no precipitation in sight given the current oceanographic conditions, the burning this year wreaked havoc on air quality and public health conditions across SE Asia. In the absence of being able to rewrite history and establish climate monitoring stations around SE Asia before the industrial revolution, we must focus on incorporating strategically placed, high-resolution (monthly to seasonal) paleo-records of climate variability from chemical and biological fossils.
The oceanic conditions of the tropical Pacific, and in particular the Western Pacific Warm Pool (WPWP), an area of generally elevated sea surface temperature (SST), is believed to be one of the greatest influences on global climate. Small changes to SST, precipitation and circulation in this region can lead to large scale global teleconnections as can be seen by the global impacts of the El Niño Southern Oscillation (ENSO). In 2012, Karnouskas et al. identified a mode of variability named the Pacific Centennial Oscillation (PCO) defined by coherent patterns of sea level pressure, SST and precipitation variability at 100 year time frequencies in the output of three General Circulation Models (GCMs). The PCO was found to have wide ranging impacts on surface temperature, SST, and precipitation that varied in normal, El Niño and La Niña modes. The impacts were global but were particularly strong in the Southeast Asian region.
With a lack of instrumental records to test the validity of the PCO as a driver of climate variability on centennial time-scales, we propose to evaluate the fidelity of the PCO from strategically located, already collected coral cores from Vietnam, the Philippines and Micronesia. The majority of cores are longer than 400 years old, allowing for a minimum of four realisations of the PCO cycle. The cores are from two locations sensitive to the PCO system, and one that is insensitive to the system. The ability to generate sub-annual resolution records of SST, precipitation, and sea surface salinity from stationary corals makes corals an ideal resource for investigating long-term variability of the PCO.
- Earth Observatory of Singapore
- Ministry of Education, Singapore
Kristopher Karnauskas, University of Colorado Boulder
Konrad Hughen, Woods Hole Oceanographic Institution