Complete maps of the aspect sensitivity of VHF atmospheric radar echoes

Authors

R. M. Worthington, University of Wales, Aberystwyth
R. D. Palmer, University of Nebraska - Lincoln
S. Fukao, Kyoto University

Document Type

Article

Date of this Version

1999

Citation

Ann. Geophysicae 17, 1116±1119 (1999)

Comments

© EGS - Springer-Verlag 1999

Abstract

Using the MU radar at Shigaraki, Japan (34.85°N, 136.10°E), we measure the power distribution pattern of VHF radar echoes from the mid-troposphere. The large number of radar beam-pointing directions (320) allows the mapping of echo power from 0° to 40° from zenith, and also the dependence on azimuth, which has not been achieved before at VHF wavelengths. The results show how vertical shear of the horizontal wind is associated with a definite skewing of the VHF echo power distribution, for beam angles as far as 30° or more from zenith, so that aspect sensitivity cannot be assumed negligible at any beam-pointing angle that most existing VHF radars are able to use. Consequently, the use of VHF echo power to calculate intensity of atmospheric turbulence, which assumes only isotropic backscatter at large beam zenith angles, will sometimes not be valid.