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Simulating the development of the double warm core structure of intense tropical cyclones on IU's supercomputers

Project Leads: Dr. Chanh Kieu (Indiana University), Dr. Vijay Tallapragada (NOAA/NCEP/EMC), Dr. Da-Lin Zhang (University of Maryland, College Park), Zachary Moon (Department of Geological Sciences, Indiana University)

Research made possible by:  Big Red II and Karst supercomputers, Scientific Applications and Performance Tuning (SciAPT)

tropical cyclone structure
Figure 1. An example of the TC structure for a specific snapshot after 120-h into integration in an HWRF simulation, showing existence of the double warm core at the vortex center. Superimposed are the three-dimensional flows at the surface (white vectors) and at 75 hPa (yellow vectors) along with surface wind speed (shaded color at the bottom, m s-1). The double warm temperature anomalies are the two purple regions at the center of the vortex.

The IU research group led by Dr. Chanh Kieu (Geological Sciences) is investigating the double warm core structure of intense TCs with ultra-high resolution simulations using IU’s Big Red II high-performance computing system. By conducting idealized simulations for TC-like vortices using the state-of-the-art Hurricane Weather Research and Forecasting (HWRF) model, IU’s hurricane modeling group is able to simulate the entire development process of the double warm core structure associated with intense TCs. This confirms the formation of the double warm core structure in similar to what was observed in the NCEP real-time TC forecasts. Figure 1 shows an example of the TC structure for one specific snapshot after 120-h into integration in an HWRF simulation, showing existence of the double warm core at the vortex center. This confirms the formation of the double warm core structure in idealized experiments similar to what observed in the National Center for Environmental Prediction real-time TC forecasts.

The success of these idealized simulations allows for deeper analyses of TC development, which are conducted to examine potential impacts of the lower stratosphere on TC structure and on the distribution of intense TC in different ocean basins. The outcome from this study will have significant implications for studies of the TC-climate connection, and will shed light on the structure of TCs at a new high intensity limit. 

The relationship between tropical cyclones (TC) and climate plays a critical role in long-term projections of TC activity in various scenarios of global climate change. Because of inadequate understanding of the TC physical processes and their interactions, studies of the TC-climate connection produce a wide range of projections, and no real consensus on future changes in TC activity. Previous studies of the impact of climate change on TC intensity have generally been restricted to variations in sea surface temperature (SST) or changes in the mid-tropospheric moisture. Linking change in TC intensity to SST is expected, but recent studies seem to indicate another role for the upper troposphere in the TC-climate relationship.

During 2012-2014, experimental real-time TC forecasts in the North Western Pacific basin showed some unusual structure for Category 2 TCs and above. Specifically, intense TCs in this area frequently develop two peaks of temperature anomaly at the storm center, with a thin layer of upper inflow between the tropopause and the outflow level. While these features are difficult to verify, the consistency in reproducing this double warm core feature suggests that such a peculiar structure should have some connection with the lower stratosphere aloft that is not yet fully understood.


The mission of the Scientific Applications and Performance Tuning (SciAPT) group is to deliver and support software tools that promote effective and efficient use of IU's advanced cyberinfrastructure which, in turn, improves research and enables discoveries.

NSF GSS Codes:

Primary Field: Atmospheric Sciences (301)

Secondary Field:  Computer Science (401) Data Modeling