Abstract
Abstract The design of a sodar that uses ultrasound to remotely sense drop size distributions in rainfall is described. The Doppler shift is proportional to a drop's terminal velocity and gives a measure of the drop diameter, whereas the intensity of scatter gives a measure of the number of drops of each diameter. Since rain drops cause Rayleigh scattering in the usable range of sound frequencies, the intensity of this scattering is proportional to the fourth power of the frequency. Because attenuation rises with frequency, a 40-kHz operating frequency was found to maximize the power reflected back from rain drops. Verification of design factors was undertaken in an anechoic chamber. Field tests showed that Doppler frequency spectra and drop size concentrations matched expected profiles. Rainfall intensities inferred from the Doppler spectrum over time were within 20% of the values obtained by conventional rain gauges. The instrument was found to be useful for obtaining information in the lowest 10 m of t...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
