The Extended Flight Level Dataset for Tropical Cyclones (FLIGHT+) consists of high resolution aircraft observations from thousands of U.S. Air Force Reserve (AFRES) and NOAA Hurricane Hunter flights. The majority of these flights were tasked for operational reconnaissance missions into tropical cyclones (TCs), however the dataset also includes a significant number of research flights as well. Most flights occurred in TCs in the Atlantic basin, however a number of flights are also included from TCs in the Eastern Pacific, as well as a few TCs in the Central Pacific and Western Pacific basins. The current version of the dataset spans the years 1999-2013. Eventually the dataset may span the entire era of modern aircraft observations, from 1977 up to the present time. The dataset consists of individual Network Common Data Format (NetCDF) files, one for each TC that was flown. Each file contains all of the relevant flight level data for all the flights for that TC, with data parameters grouped as follows: (1) standardized, earth-relative flight level data and associated navigational information for all of the common flight level data parameters, (2) high resolution positional information for the TC wind centers, obtained from the Willoughby-Rahn center-finding method, (3) earth-relative wind speed and rainfall rate data from the Stepped Frequency Microwave Radiometer (SFMR) instrument (when available, generally from 2007 onward), (4) metadata from application of an automated algorithm to parse the full flight paths into radial legs (the segments of the flight path that are essentially straight-line paths into or out of the TC center), (5) meteorological flight level and SFMR data parameters for the good radial flight legs in both time and radius coordinates. The dataset also includes a number of summary metadata that characterize various aspects of the radial legs, such as whether the leg was inbound or outbound relative to the TC center, the flight level that the plane flew at during the leg, the peak flight level and SFMR surface wind speeds measured during the radial leg, and the latitude/longitude and corresponding radius from the TC center of each wind maxima. The wind parameters in the dataset have been carefully quality controlled to minimize file reading errors. Visual checks have been conducted to ensure that the peak values of each flight are reasonable. Additional quality control measures have also been applied to the SFMR data. By making all of these data easily accessible in standardized and structured NetCDF data files, FLIGHT+ offers the research community an enormous trove of research-grade data that should prove valuable for wind risk applications and research studies into the TC life cycle and the challenging problems of rapid intensification and structure change.
