The NCAR GPS dropwindsonde

The National Center for Atmospheric Research (NCAR), in a joint effort with the National Oceanic and Atmospheric Administration (NOAA) and the German Aerospace Research Establishment, has developed a dropwindsonde based on th e Global Positioning System (GPS) satellite navigation. The NCAR GPS dropwi ndsonde represents a major advance in both accuracy and resolution for atmo spheric measurements over data-sparse oceanic areas of the globe, providing wind accuracies of 0.5-2.0 m s(-1) with a vertical resolution of similar t o 5 m. One important advance over previous generations of sondes is the abi lity to measure surface (10 m) winds. The new dropwindsonde has already bee n used extensively in one major international research field experiment (Fr onts and Atlantic Storm Track Experiment), in operational and research hurr icane flights from NOAA's National Weather Service and Hurricane Research D ivision, during NCAR's SNOWBAND experiment, and in recent CALJET and NORPEX El Nino experiments. The sonde has been deployed from a number of differen t aircraft, including NOAA's WP-3Ds and new Gulfstream IV jet, the Air Forc e C-130s, NCAR's Electra, and a leased Lear-36. This paper describes the ch aracteristics of the new dropwindsonde and its associated aircraft data sys tem, details the accuracy of its measurements, and presents examples from i ts initial applications.