Role of Physical Processes in the Southern Ocean CO2 Sink

Northwest Research Associates, Incorporated, Seattle WA

Investigators

Abstract

CMIP5, the Coupled Model Intercomparison Project (Phase 5) promotes a standard set of earth system model climate simulations in order to: i) evaluate how realistic our models are in simulating climate of the recent past, ii) provide projections of future climate change on two time scales, one near term (out to about 2035) and one long term (out to 2100 and beyond), and iii) understand some of the factors responsible for differences in model projections, including quantifying some key feedbacks such as those involving clouds and the carbon cycle. This project aims to analyse CMIP5 model output to assess the impacts of physical processes in the Southern Ocean that influences surface water pCO2 variation, and air-sea CO2 uptake. Systematic model intercomparisons will be carried out to tackle three main questions: 1) How significant are the zonal variations in surface ocean pCO2 throughout the entire Southern Ocean, hence, how representative are conditions in Drake Passage of ESMs in other areas of the Southern Ocean? 2) Does the rate of pCO2 increase in the surface waters of the Southern Ocean concur with the increase of total Dissolved Inorganic Carbon (DIC) upwelled to the ocean surface south of the fronts? 3) What physical processes can explain the excessive surface water pCO2 concentrations found near the Polar Front in half of the eight available ESMs? Increased knowledge of future climate change is in the interest of the US.