NERSC Initiative for Scientific Exploration (NISE) 2009 Awards

Sensitivity to the Carbon-Nitrogen Cycle in the Ocean

Steven Yeager, National Center for Atmospheric Research

Sponsoring NERSC Project: Climate Change Simulations with CCSM: Moderate and High Resolution Studies (mp9), Principal Investigator: Warren Washington, National Center for Atmospheric Research

Two 200-year CCSM4 integrations with the 2-degree atm, 1-degree ocean to be added to previously completed simulations to obtain statistically significant results.

Two CCSM4 integrations with the 2 degree atm, 1 deg ocean version have been completed (at another site). These were present day cases without the Carbon-Nitrogen scheme. One experiment has the overflow parameterization on, the other does not have this scheme. While comparing the Atlantic MOC (AMOC) variability in these two cases, we noticed that there were substantial differences in amplitudes and frequency of the AMOC oscillations. We require computer time to continue both these cases 200 years more (each) to get statistically significant signals.