National Oceanographic Partnership Program (NOPP) Tropical Cyclone Principal Investigators Meeting at the University of Miami, 1-2 March 2012
Federal program managers and Principal Investigators (PIs) funded through the NOPP topic – Improving Tropical Cyclone Intensity – met for their annual review meeting on the campus of the Rosenstiel School of Marine and Atmospheric Science of the University of Miami in Miami, Florida on 1-2 March 2012. More than 50 scientists, graduate students, post-docs, and program managers from ONR, NOAA, and BOEM, as well as NOPP Office staff attended the meeting. This NOPP topic focuses on improving Tropical Cyclone (TC) intensity prediction models. Significant progress has been made such as: improving TC intensity forecasts with theoretically-based statistical models, assimilating data using the current TC prediction models, and developing a new generation of coupled atmosphere-wave-ocean models for TC prediction. A summary of presentations and results from the NOPP funded projects are highlighted below.
A Unified Air-Sea Interface for Fully Coupled Atmospheric-Wave Ocean Models and Tropical Cyclone Prediction: The modeling team, led by Dr. Shuyi Chen, with scientists from University of Miami, the Naval Research Laboratory – Monterey (NRL-MRY) and Stennis Space Center (NRL-SSC), the National Renewable Energy Laboratory (NREL), and University of Washington, has developed a unified air-sea interface module. This new coupled atmosphere-wave-ocean modeling framework represents a transformative approach that has fundamentally changed the way the atmosphere, wave, and ocean models will be coupled. This standardized system allows researchers to develop and test air-sea coupling parameterizations and to better facilitate research-to-operation activities. It also allows for future ensemble forecasts using coupled models that can be used for coupled data assimilation and assessment of coupled uncertainties. It has been implemented in the fully coupled Navy operational model and in research community models. The fully coupled atmosphere-wave-ocean modeling systems improve forecasts of TC structure and intensity, as well as ocean circulation and surface waves in both the Atlantic and Pacific Oceans.
Physical Parameterizations for Coupled Models for Improving Intensity Prediction of Tropical Cyclones: A science team related to the coupled atmosphere-wave-ocean modeling project led by Dr. Isaac Ginis of University of Rhode Island, has focused on developing physical parameterizations for coupled models, including wave-current interaction, sea spray flux parameterization, and air-water two-phase physics. These physical parameterizations are designed to better represent the air-sea coupling processes that occur within tropical cyclones, and will be implemented and tested in the current Geophysical Fluid Dynamic Laboratory (GFDL) and Hurricane Weather Research and Forecasting (HWRF) models.
Implementation of a Wave-Driven Coupled Sea Spray and Surface Flux Algorithm: In partnership with the research teams led by Dr. Isaac Ginis and Dr. Shuyi Chen, Dr. Chris Fairall is working on the sea spray flux parameterization portion of the physical parameterization. The group has proven that TC models are sensitive to the representation of surface fluxes.
Initialization, Prediction, and Diagnosis of the Rapid Intensification of Tropical Cyclones using the Australian Community Climate and Earth System Simulator (ACCESS): The group of scientists led by Dr. Michael Reeder from the Centre for Australian Weather and Climate have made significant progress toward a better TC prediction system using the ACCESS with a 4DVar data assimilation capability. The ACCESS-based TC forecast system has shown improvements in forecasting TC intensity and structure (e.g., storm size) over the Pacific Ocean.
Augmentation of Early Intensity Forecasting in Tropical Cyclones: A science team led by Dr. J. Scott Tyo from the University of Arizona, NRL-MRY, and Joint Typhoon Warning Center (JTWC) has developed a satellite data-based technique to characterize the axisymmetry of TCs and correlate the information with storm intensity in order to develop a parametric relationship. This technique has been tested over the West Pacific and is shown to be robust; it works well with both strong and weaker TCs. The science team is working toward a fully automated system for estimating TC intensification trends. This technique will be tested over the East Pacific and Atlantic basins.
Improving Tropical Cyclone Intensity Forecasting with Theoretically Based Statistical Models: A theoretically based statistical model has been developed by a science team led by Dr. Wayne Schubert from Colorado State University (CSU) and scientists from NOAA and NRL-MRY. The statistical model focuses on three main areas: 1) TC vortex structure in the inner core region, 2) upper ocean response to TCs, and 3) applications in TC intensity forecast models. The model has shown improvement forecasting TC intensity with the incorporation of additional TC inner core and upper ocean data.
Impacts of Turbulence on Hurricane Intensity: A team of scientists from York University and the National Center for Atmospheric Research (NCAR), led by Dr. Yongsheng Chen, have been investigating impacts of the turbulence parameterizations on TC intensity by examining the nature of radial turbulent diffusion in a TC. They are doing this by computing the small-scale turbulence (i.e., a large eddy simulation or LES) using the Advanced Weather Research and Forecasting model (ARW), applied to an idealized tropical cyclone. They have made significant progress toward a better understanding of the sensitivity of model-simulated TC structure and intensity to horizontal and vertical model grid resolutions and diffusion parameters.
Achieving Superior Tropical Cyclone Intensity Forecasts by Improving the Assimilation of High-Resolution Satellite Data into Mesoscale Prediction Models: The science team is led by Dr. Chris Velden from University of Wisconsin-Madison and includes scientists from University of Miami and NRL-MRY. The team has been working toward the development and refinement of data assimilation (DA) techniques. In order to improve high-resolution numerical analyses and TC intensity forecasts, the team plans to supplement the current atmospheric observation capabilities with optimal configurations and assimilation methodology that will also take advantage of advanced full-resolution satellite-derived observations. The project could provide a pathway towards advanced satellite DA in operational TC forecast models. Recently, the team made progress using the Ensemble Kalman Filter (EnKF)-based DA within the NCAR and the Navy modeling system frameworks.
Data Assimilation and Predictability Studies for Improving Tropical Cyclone Intensity Forecasts: A team of scientists, led by Dr. Takemasa Miyoshi, from University of Maryland (UMD), NRL-MRY, and meteorological agencies from Japan and China, have made significant progress in the development of a Local Ensemble Transform Kalman Filter (LETKF) DA system. Experiments during Typhoon Sinlaku, with observations from the Tropical Cyclone Structure (TCS)-08 field program over the West Pacific, have shown a significant improvement in TC intensity forecasts. In addition to the atmospheric data, the sea surface temperature (SST) data has been used to quantify uncertainties in the model due to the air-sea interaction.