NOAA Intensity Forecasting Experiment (IFEX)

1. NOAA Intensity Forecasting Experiment (IFEX) PDF available at AOML anonymous FTP: ftp.aoml.noaa.gov /pub/hrd/rogers/HFP/IFEX_framework.pdf

2. Motivation • Significant improvement in track forecasts over past 30 years • Much less improvement in intensity forecasts – Why? • gaps in our understanding of the physics of tropical cyclones and their interaction with the environment. • deficiencies in routinely collecting data and assimilating it into the modeling system • limitations in the numerical models themselves • Accurate forecasts will rely heavily on the use of improved numerical modeling systems, which in turn will rely on accurate observational datasets for assimilation and validation.

3. Overview of IFEX (15 July – 30 Sept) • HRD’s efforts will work toward improving forecasts of tropical cyclone intensity and rainfall by providing data to improve the operational numerical modeling system (i.e., HWRF) and by improving our understanding of the physics of intensity change and rainfall • IFEX will focus on providing measurements of tropical cyclones at all stages of the tropical cyclone's life cycle, from pre-genesis to intensification and subsequent landfall or decay over water • Will provide invaluable information from sparsely observed environments • The ability to target multiple basins provides greater flexibility for observing tropical cyclones at different stages of their life cycle

4. Proportion of HRD research flights stratified by lifecycle stage in the P-3 era (1976-2004)

5. Requirements and Recommendations • Requirements: High Priority • Collect observations throughout the life cycle of a tropical cyclone for the development of 3-D variational assimilation of the hurricane core circulation. • Collect observations of the atmosphere and ocean in and around the storm scale circulation that can be used to develop an evaluation and validation package for the high resolution HWRF.

6. Requirements and Recommendations (cont.) • Requirements: High Priority • Collect observations in a variety of atmospheric/oceanic conditions (e.g. atmospheric shear, warm core eddies) to assess the influence of these features on observed and model TC intensity and structure changes. • Improve understanding and develop improved model representations of sea spray/surface flux effects on boundary layer structure and microphysics, especially in the core and rainbands. Develop techniques for evaluating ocean vertical mixing parameterizations against observed data.

7. Requirements and Recommendations (cont.) • Recommendations: Medium Priority • Improve the understanding of the phase changes of moisture. • Determine the storm intensity and structure change during decay over cold water.

8. Flight modules • Tropical Cyclogenesis Module • Investigate role of low- and mid-level vortex interactions in genesis (2 P-3’s, 1 G-IV) • Mature Storm Module • Collect observations from the sub-surface to the upper atmosphere for a mature TC, from the inner core to the synoptic environment (2 P-3’s, 1 G-IV) • Tropical Cyclone Wind Fields near Landfall Module • Mapping of the TC kinematic and thermodynamic changes during landfall (2 P-3’s) • Saharan Air Layer Module • Study the mechanisms by which the SAL’s embedded mineral dust, thermodynamic properties, and low-level wind surge affect Atlantic TC genesis and intensity change (1 G-IV)

9. Partnering Experiments for 2005 • NASA TCSP (multiple P.I.’s TBD) • mid-June – early August 2005 • NASA aircraft based in San Jose, Costa Rica • Science team TBD by 1 January • NSF RAINEX (Houze, Chen, Lee) • August-September 2005 • Ground operations based in Miami, flights in Atlantic • Proposal has been accepted • Planning meeting 15-17 November in Miami (at RSMAS) • NOAA Ocean Winds (Chang) • Same as previous years

10. Tropical Cyclone Life Cycle and Experiment Coverage IFEX (NOAA) TCSP (NASA) RAINEX (NSF) Ocean Winds (NOAA) time tropical depression tropical wave tropical storm hurricane genesis organization mature landfall/ decay