Cloudradar observations of insects in the UK convective boundary layer.

Radar has been applied to the study of insect migration for almost 40 years, but most entomological radars operate at Xband 9.4 GHz, 3.2 cm wavelength and can only detect individuals of relatively large species, such as migratory grasshoppers and noctuid moths, over all of their flight altitudes. Many insects including economically important species are much smaller than this, but development of the requisite higher power andor higher frequency radar systems to detect these species is often prohibitively expensive. In this paper, attention is focused upon the uses of some recentlydeployed meteorological sensing devices to investigate insect migratory flight behaviour, and especially its interactions with boundary layer processes. Records were examined from the verticallypointing 35 GHz ‘Copernicus’ and 94 GHz ‘Galileo’ cloud radars at Chilbolton Hampshire, England for 12 cloudless and convective occasions in summer 2003, and one of these occasions 13 July is presented in detail. Insects were frequently found at heights above aerosol particles, which represent passive tracers, indicating active insect movement. It was found that insect flight above the convective boundary layer occurs most often during the morning. The maximum radar reflectivity an indicator of aerial insect biomass was found to be positively correlated with maximum screen temperature. Copyright © 2009 Royal Meteorological Society [ABSTRACT FROM AUTHOR]