Characterizing Tropical Cyclones in the Energy Exascale Earth System Model Version 1

• Published in: Journal of Advances in Modeling Earth Systems
• Main Authors: Balaguru, Karthik, Leung, Lai-Yung Ruby, Van Roekel, Luke, Golaz, Jean-Christophe, Ullrich, Paul A., Caldwell, Peter M., Hagos, Samson M., Harrop, Bryce E., Mametjanov, Azamat
• Language: unknown
• Published: 2023
• Subjects: 54 ENVIRONMENTAL SCIENCES; Pacific; North Atlantic
• Online Access: http://www.osti.gov/servlets/purl/1668807; https://www.osti.gov/biblio/1668807; https://doi.org/10.1029/2019ms002024

In this study, we analyze the realism with which Tropical Cyclones (TCs) are simulated in the U.S. Department of Energy's Energy Exascale Earth System Model (E3SM) version 1. Results are presented from coupled simulations at both low and high-resolution with a focus on the latter. Compared to the low-resolution version (with approximate grid spacing of 110 kilometers in the atmosphere and 30-60 kilometers in the ocean), the representation of TCs improves considerably in the high-resolution version (with approximate grid spacing of 25 kilometers in the atmosphere and 6-18 kilometers in the ocean). Significant improvements are found in the global TC frequency, TC lifetime maximum intensities and the relative distribution of TCs among the different basins. However, spurious TC activity is found in some regions, notably in the subtropical South Pacific and South Atlantic. Contrasting the simulated large-scale TC environment with observations reveals that the model environment is relatively more favorable for TC development in those regions. Further analysis indicates that these biases are likely related to those in thermodynamic Potential Intensity caused by systematic SST biases in the coupled model. TC-ocean interaction is also examined in the high-resolution version of the model. The salient features of the ocean's response to TC-induced mixing, and the ocean's impact on TC intensification are reproduced well. Finally, an evaluation of the influence of El Ni\~no Southern Oscillation (ENSO) on TCs in the high-resolution version of the model reveals that the ENSO-TC relationship in the model has the right sign and is significant for the North Atlantic and Northwest Pacific, albeit weaker than in observations. In summary, the high-resolution version of the E3SM model simulates TC activity reasonably and hence could be a useful tool for TC-related research.