Evaluation of On-Board and Ground-Based Meteorological Measurements
Hoffmann, W. C., Fritz, B.
Contact: Clint Hoffmann
US Dept. of Agriculture
2771 F&B Road
College Station, TX 77845
All pilots and especially agricultural pilots know the importance of monitoring weather. For an ag pilot, weather not only affects the safe completion of a flight but also the effectiveness of a spray job. Years of research have shown that wind speed and direction are the primary factors that influence spray drift. As pesticide labels become more descriptive regarding meteorological conditions under which products may be applied, it is essential to both monitor and record wind speed and direction and insure that applications are made under the specified conditions.
This study reports on the correlation between wind speed and direction measurements from and on-board aircraft probe and from hand-held and sonic anemometers on the ground. An Aircraft-Integrated Meteorological Measurement System (AIMMS) was mounted onto an AirTractor 402B. The AIMMS system reports wind speed and direction in real-time to the pilot and can be integrated into the application log of a GPS system. A spray track was set up in a cotton field over which the aircraft made repeated passes under a variety of meteorological conditions. Simultaneous to the spray runs, a variety of hand-held and sonic anemometers were operated on the ground. The outcome of these studies will allow applicators to confidently ensure that they are complying with a pesticide label and will allow regulators to have correlated measurements taken by a field technician with those measured by the AIMMS probe.
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