Resolution dependence of future tropical cyclone projections of CAM5.1 in the US CLIVAR Hurricane Working Group idealized configurations

The four idealized configurations of the US CLIVAR Hurricane Working Group are integrated using the global Community Atmospheric Model, v5.1 at two different horizontal resolutions, approximately 100km and 25km at the equator. The low-resolution publicly released configuration is a poor predictor of the sign of the high-resolution configuration's change in the total number of tropical cyclones in a warmer climate. However, it does predict the sign of the high-resolution configuration's change in the number of intense tropical cyclones in a warmer climate. We find that in the high-resolution configuration, both increased CO2 elevations and elevated sea surface temperature (SST) independently lower the number of weak tropical storms and shorten their average duration. Conversely, increased SST causes more intense tropical cyclones and lengthens their average duration.