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Tropical Cyclone Rapid Intensification (TCRI) DRI

The purpose of this Office of Naval Research Departmental Research Initiative (DRI) is to address the prediction of rapid intensification in tropical cyclones (TC). Mesoscale numerical weather prediction (NWP) models have recently shown improving skill for intensity predictions, with progress in model physics, data assimilation and initialization, coupling, and resolution all contributing. However, these forecasts continue to lag statistical guidance verification for storms with the strongest and fastest intensification rates. Research suggests fundamental elements are missing in model representation of tropical cyclone structure and dynamics. ONR’s goal is to foster basic research innovation to better understand the highly complex nature of process and scale interactions that modulate TC intensity change.


Investigations should focus on the understanding of the TC structure evolution as it relates to the intensification problem (e.g., through theory, simulations, observations and model development). The following are examples of research topics that may address the overarching scientific issues related to improving the understanding of physical processes that contribute to TC rapid intensification.

  1. The relationship between latent heating distribution and microphysical representation: Tropical cyclone theory describes latent heating and warm core development in different symmetrical and asymmetrical frameworks. How do these theories account for observed latent heating and hydrometeor distributions? How do different microphysical processes influence the latent heating distribution? How do these observations differ from model representations?
  2. Boundary layer characteristics in different intensity change regimes: A wide variety of inflow angles, boundary layer heights, and heat fluxes are observed in TCs. How do tangential winds and frictional convergence zones change during intensification? How do ocean surface fluxes interact with turbulent processes to module intensification?
  3. The formation of eyewalls and the intensification process: Symmetric microphysics near and inside the radius of maximum winds contributes to intensification. Do diabatic or boundary layer processes dominate eyewall formation? How does intensity change relate to eyewall characteristics? How are the organizational changes during RI distinct from those during periods of more gradual intensification?
  4. Predictability of modeled scale interactions:
    Increased resolution of mesoscale models have contributed to improvements in structure and intensity representation. What are limits storm structure and intensification representation at different spatial scales? How can large eddy simulations (LES) be used to understand and augment coarser scale modeling with respect to turbulence and boundary layer processes? To what extent can targeted observations inside the TC core be used in data assimilation systems to better represent physical characteristics in the model?

This DRI is expected to run for five years, from FY20 to FY24. Collaboration is encouraged, and it is anticipated that a science team will be formed, workshops held to coordinate research activities, and a multi-year observational component will be included. ONR's Marine Meteorology Program has established an initial collaboration with NOAA’s ongoing Intensity Forecasting EXperiment (IFEX) field program. ONR also seeks to collaborate with other agencies to augment spatial and temporal observation of TC intensification by leveraging one or more of the community research projects that are currently in the planning stages

Request for Planning Letters

The letter should include:

  • A cover sheet with project title and contact information for the principal and co-investigators, including full mailing address, e-mail address and phone number for each
  • A maximum 3-page synopsis of the proposed research, including a rationale, questions and/or hypotheses to be addressed, figures that show the science, the approach, and anticipated results
  • An estimated itemized budget with approximate cost per year
  • Up to one page of relevant references to the literature
  • A 1-page biographical sketch for each investigator, with a focus on research activities and publications relevant to the proposed research

Purpose of Planning Letters

The purpose of the planning letter is to allow investigators to submit their ideas for ONR to evaluate, provide feedback, and indicate whether full proposals are encouraged. ONR will respond to planning letters within one month of receipt to allow sufficient time for full proposal preparation and submission by July 1, 2019.  It is anticipated that awards will be made with funds available in the first quarter of FY20.

While the main window for lead proposals has closed, ONR will continue to consider supplemental or applied research projects. Please refer to the current Marine Meteorology Planning Letter guidelines and indicate your desire to work with the TCRI project and team.