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Abstract
Radar winds are a useful source of observations which can be used to improve weather forecasts. Currently two types of radar winds are assimilated into the operational forecast models. Wind profilers are able to provide winds up to a few km in height every 15 minutes or so in nearly all weathers but only above the radar. Rain radars can provide winds out to a considerable horizontal distance from the radar, but only where there is precipitation. During the summer insects are relatively common and can be detected in the lowest km by the operational radar network and have the potential to provide winds in the boundary layer out to 20 or 30km from the radar. Such evolving surface winds could provide a valuable data source on developing convective airflows before the precipitation forms, and if successfully assimilated into a high resolution rapid update forecast model could improve the short term forecasts of convective storm development.
The development of an operational system to sense the insect winds is not trivial. Firstly, the current radars are designed to sense precipitation and tend to reject the insect returns. Secondly, the insect returns are quite weak and close to the radar sensitivity and can often be confused with echoes from the ground. Thirdly, the insects themselves may be actively flying and so the velocities are not representative of the air flow. This talk will discuss the challenges in identifying and extracting insect returns, the frequency of occurrence of such returns, and an assessment of the uncertainty and bias of the velocity measurements and how they might be assimilated into operational models.