Overview of the field phase of the Fronts and Atlantic Storm-Track EXperiment (FASTEX) project

The field phase of the Fronts and Atlantic Storm-Track EXperiment (FASTEX) project took place between 5 January and 27 February 1997 with the deployme nt of a unique set of observing facilities across the North Atlantic. The m ajor objective was to document the life cycle of a representative set of mi d-latitude cyclones. Other objectives were to rest the practical feasibilit y of 'adaptive' observations with a view to improving the prediction of the se same cyclones and to document the internal structure of the associated c loud systems using combined airborne Doppler radars and dropsondes. Another goal of FASTEX was to measure air-sea exchange parameters under conditions of strong winds with high seas. These objectives were successfully achieved. Intensive Observation Periods were conducted on 19 occasions. High-resolution vertical profiles through t he same cyclones at three different stages of their life cycle have been ob tained on more than 10 occasions. The calculation of critical areas where f urther observations were needed to limit the growth of forecast error, was undertaken using different techniques, and flights were planned and execute d in these areas in time to achieve this. Combined dropsonde and Doppler ra dar observations of cloud systems are available for 10 cases. A unique air- sea turbulent exchange dataset has been obtained.