CESM Century-Scale Climate Experiments with a High-Resolution Atmosphere

PI Name: 
Warren Washington
PI Email: 
Allocation Program: 
Allocation Hours at ALCF: 
200 Million
Research Domain: 
Earth Science

Researchers in the Climate Change Prediction group at the National Center for Atmospheric Research (NCAR) will carry out various sets of climate change simulations using the latest release of the Community Earth System Model (CESM). This INCITE research builds upon NCAR’s previous and collaborative work on how weather and climate extremes could change in a climate that is warmer in the future by obtaining data from simulations totaling 500 years’ worth of climate change modeling under various scenarios.

Time-slice simulations are suitable for investigating climate and weather extremes by removing the long-term model bias and providing improved statistics. These simulations will be performed for the present-day climate from 1979–2012 (34 years) and a future scenario for 2070–2099 (30 years) in the mesoscale range (~200–2,000 km). Once the control or near-equilibrium 1850 initial dataset becomes available in early 2015, the researchers will also complete one historical (1850–2005) simulation followed by two 100-year future scenarios, as follows: (1) a business-as-usual case with increasing greenhouse gases (GHGs), and (2) a scenario incorporating the most aggressively low GHG emissions possible. The project will also address spread in the climate model’s sensitivity—a major factor that contributes to ranges in climate change projections—via two other simulations. One will increase carbon dioxide (CO2) in the atmosphere at regular intervals until it is four times current levels, whereas another quadruple CO2 levels instantaneously then integrate until the model reaches equilibrium (approximately 100 years).