A GPS dropsonde is a scientific instrument deployed from research and operational aircraft that descends through the atmosphere by a parachute. The dropsonde provides high-quality, high vertical resolution profiles of atmospheric pressure, temperature, relative humidity, wind speed and direction from the aircraft flight level to the surface over oceans and remote areas. Since 1996, GPS dropsondes have been routinely dropped during hurricane reconnaissance and surveillance flights to help predict hurricane tracks and intensity. From 1996 to 2012, NOAA has dropped 13,681 dropsondes inside hurricane eye walls and in the surrounding environment for 120 tropical cyclones (TCs) or hurricanes. All dropsonde data have been collected, reformatted to one format, and consistently and carefully quality-controlled using state-of-art quality-control (QC) tools. Three value-added products, the vertical air velocity and the radius and azimuth angle of each dropsonde location, are generated and added to the dataset. As a result, a long-term (1996-2012), high-quality, high-vertical resolution (~5-15 m) GPS dropsonde dataset is created and made readily available for public access. The dropsonde data collected during hurricane reconnaissance and surveillance flights have improved TC track and intensity forecasts significantly. The milestones of dropsonde data s impact on hurricane studies are summarized. The scientific applications of this long-term dropsonde dataset are highlighted, including characterizing TC structures, studying TC environmental interactions, identifying surface-based ducts in hurricane environment which affect electromagnetic wave propagation, and validating satellite temperature and humidity profiling products.
A Long-Term, High-quality, High Vertical Resolution GPS Dropsonde Dataset for Hurricane and Other Studies