Estimating raindrop size distributions using microwave link measurements: potential and limitations

<p>We present a novel method of using two or three collocated microwave link instruments to estimate the three parameters of a gamma raindrop size distribution (DSD) model. This allows path-average DSD measurements over a path length of several kilometers as opposed to the point measurements o...

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Bibliographic Details
Main Authors: T. C. van Leth, H. Leijnse, A. Overeem, R. Uijlenhoet
Format: Article
Language:English
Published: Copernicus Publications 2020-04-01
Series:Atmospheric Measurement Techniques
Online Access:https://www.atmos-meas-tech.net/13/1797/2020/amt-13-1797-2020.pdf
Description
Summary:<p>We present a novel method of using two or three collocated microwave link instruments to estimate the three parameters of a gamma raindrop size distribution (DSD) model. This allows path-average DSD measurements over a path length of several kilometers as opposed to the point measurements of conventional disdrometers. Our method is validated in a round-trip manner using simulated DSD fields as well as five laser disdrometers installed along a path. Different potential link combinations of frequency and polarization are investigated. We also present preliminary results from the application of this method to an experimental setup of collocated microwave links measuring at 26 and 38&thinsp;<span class="inline-formula">GHz</span> along a 2.2&thinsp;<span class="inline-formula">km</span> path. Simulations show that a DSD retrieval on the basis of microwave links can be accurate under idealized conditions. We found that a triple-link retrieval provides little added benefit over a dual-link retrieval in terms of accuracy or precision. In practice, the accuracy and success rate of any retrieval is highly dependent on the stability of the base power level as well as the precision of the instruments and in particular the quantization applied to the recorded power level.</p>
ISSN:1867-1381
1867-8548