Meteorological Observations with the Aerosonde Robotic Aircraft

Currently there are limited 'in situ' atmospheric measurements over many regions of the globe. The Aerosonde, a robotic unmanned aerial vehicle (UAV), provides a new observational platform for gathering data in remote regions and the unique capacity to target observations in response to the needs of forecasters and forecast models. The ultimate aim of this system is to improve current forecasting and warning systems. Further information on Aerosonde can be obtained from the web site http://www.aerosonde.com.

Meteorological observations collected over Bass Strait near Sale, southeast Australia, by the Aerosonde during the Aerosonde Global Reconnaissance Facility (AGRF) Trials (March-June 2000) will be presented. These AGRF Trials provided a substantial and unique data set for mesoscale meteorology in the Bass Strait region. Aerosonde missions in this region incorporated both routine observations (for absorption into numerical models) and specific weather reconnaissance (tracking sea breezes, cold fronts and severe weather). Operations were conducted during a range of atmospheric conditions, most notably a frontal system bringing a chilly wintry blast to southeast Australia just prior to the start of winter. One of the Aerosonde Bass Strait missions during the icy weather recorded wind up to 28m/s.

Radiosonde observations can only give us a small picture of the current state of the atmosphere. For example, a feature not seen in radiosonde observations is the spatial variability in relative humidity observed by the Aerosonde. The Aerosonde's capability to sample more spatial detail than a radiosonde station for extended periods of time provides users with meteorological data that have a great potential to improve current atmospheric monitoring systems.

This paper presents an analysis of the data gathered by the Aerosonde during flights undertaken during the AGRF Trials, and compares this with data from other missions including the low-latitude Typhoon Reconnaissance Missions (September-October 2000) and the high-latitude Barrow (Alaska) Trials (August 2000).