Cloud physical properties and empirical polarimetric measurements of rain signatures at C-Band

• Main Authors: J. Steinert, M. Chandra
• Format: Article
• Language: deu
• Published: Copernicus Publications 2008-05-01
• Series: Advances in Radio Science
• Online Access: http://www.adv-radio-sci.net/6/315/2008/ars-6-315-2008.pdf

Raindrops are one type of precipitation in stratiform and convective clouds. To get relationships for describing the raindrops two different methods were used. In the first way, the microphysical properties of the liquid hydrometeors were examined. For this the use of the Rayleigh approximation for small particles (raindrops at C-Band) and the drop size distribution by Ulbrich (Γ-DSD) lead to the calculation of the reflectivity at horizontal polarisation <i>Z<sub>HH</sub></i>, the reflectivity at vertical polarisation <i>Z<sub>VV</sub></i> and the differential reflectivity <i>Z<sub>DR</sub></i>. In the second way, rain signatures were separated from polarimetric measurements. The database of these measurements consists of datasets measured by the dual polarimetric C-Band weather radar POLDIRAD (DLR, Oberpfaffenhofen). The aim of this study was then to combine and to compare the results from the real radar measurements against the theoretical calculations in the <i>Z<sub>HH</sub>-Z<sub>DR</sub></i> plane. Based on these observations and calculations, scientific results for future practical use will be presented in form of empirical equations including <i>Z<sub>HH</sub>-Z<sub>DR</sub></i>. Finally in form of scientific discussion, the <i>Z<sub>HH</sub>-Z<sub>DR</sub></i> plane will be critically assessed for outstanding problems or issues.