Wind Measurements over the North Atlantic Using a Loran‐C Dropwindsonde

The Experiment on Rapid Intensification of Cyclones over the Atlantic (ERICA) was conducted from December 1988 through February 1989. One of the principal tools for studying these storms was a newly developed Lightweight Loran Digital Dropwindsonde (L2D2). Four aircraft were equipped with this device as a means of obtaining three‐dimensional profiles of winds and other meteorological parameters as the severe winter storms intensified off the east coast of the United States. An analysis of Loran‐C coverage over the North Atlantic was first performed to determine whether a Loran‐based dropsonde could replace the Omega dropwindsonde presently used by NOAA and the U.S. Air Force. Since the results of this analysis were positive, a development program was undertaken to provide a lightweight dropwindsonde that could be dropped in the airlanes or over land, and could measure winds to greater precision than an Omega‐based system. The Loran translator and other sonde characteristics are described, as well as the aircraft‐based data system. Results of the 430 drops from four aircraft are also given, and Loran performance in the severest weather conditions is discussed. 1989 Institute of Navigation