Sixth Northeast Tropical Conference Abstracts

Global and regional aspects of tropical cyclone

activity in the CMIP5 models

Suzana J. Camargo

Lamont-Doherty Earth Observatory

Columbia University

Tropical cyclone (TC) activity is analyzed in 14 Coupled Model Intercomparison Project phase 5 (CMIP5) models. The global TC activity in the historical runs is compared with observations. The simulation of TC activity in the CMIP5 models is not as good as in higher-resolution simulations. The CMIP5 global TC frequency is much lower than observed, and there is significant deficiency in the geographical patterns of TC tracks and formation. Although all the models underestimate the global frequency of TCs, the models present a wide range of global TC frequency. The models with the highest horizontal resolution have the highest level of global TC activity though resolution is not the only factor that determines model TC activity. A cold SST bias partially explains the low number of TCs in the models. The models show no consensus regarding the difference of TC activity in two warming scenarios (RCP4.5 and RCP8.5) and the historical simulation. We examined in more detail North Atlantic and eastern North Pacific TC activity in a subset of models and found no robust changes across models in TC frequency. Therefore, there is no robust signal across the CMIP5 models in global and regional TC changes in activity for future scenarios. The future changes in various large-scale environmental fields associated with TC activity were also examined globally: genesis potential index, potential intensity, vertical wind shear and sea level pressure. The multi-model mean changes of these variables in the CMIP5 models are consistent with the changes obtained in the CMIP3 models

Characteristics of tropical cyclones in high-resolution models of the present climate

Daniel A. Shaevitz¹, Suzana J. Camargo², Adam H. Sobel^1,2 and

US CLIVAR Hurricane Working Group members


1 Department of Applied Physics and Applied Mathematics

2 Lamont-Doherty Earth Observatory


Columbia University, New York, NY

As part of the US CLIVAR Hurricane Working Group, simulations of Tropical Cyclones (TCs) in several Atmospheric General Circulation Models, forced with both climatological and historical Sea Surface Temperatures, are compared to the observational record. The number of observed TCs varies considerably between models due to the different criteria to detect TCs used in their tracking schemes. The geographic distribution of simulated TCs are overall similar to the observations in all models, though with some differences. The maximum intensity of simulated TCs varies significantly between models, due mostly to differences in model resolution. In the historical forced runs, several models demonstrate a relatively high correlation to the time series of observed TCs in the North Atlantic and North Pacific basins. In addition, all of the models correctly exhibit an eastward shift in the average position of TC formation in El Nin ̃o years in the Western North Pacific and a westward shift in the Eastern North Pacific.