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Monitoring the absolute calibration of a polarimetric weather radar

Frech, Michael and Hagen, Martin and Mammen, Theodor (2017) Monitoring the absolute calibration of a polarimetric weather radar. Journal of Atmospheric and Oceanic Technology, 34 (3), pp. 599-615. American Meteorological Society. DOI: 10.1175/JTECH-D-16-0076.1 ISSN 0739-0572

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Official URL: http://journals.ametsoc.org/doi/abs/10.1175/JTECH-D-16-0076.1

Abstract

The absolute calibration of a dual-polarization radar of the German Weather Service is continuously monitored using the operational birdbath scan and collocated disdrometer measurements at the Hohenpeissenberg observatory. The goal is to measure the radar reflectivity constant Z better than ±1 dB. The assumption is that a disdrometer measurement close to the surface can be related to the radar measurement at the first far-field range bin. This is verified using a Micro Rain Radar (MRR). The MRR data fill the gap between the measurement near the surface and the far-field range bin at 650 m. Using data from the first half of the warm season in 2014, a bias in radar calibration of 1.8 dB is found. Data from only stratiform precipitation events are considered. After adjusting the radar calibration and using an independent data sample, very good agreement is found between the radar, the MRR, and the disdrometer with a bias in smaller than 1 dB. The bias in is not captured with the classic one-point calibration, which is performed twice a day using a built-in test signal generator. This is attributed to the fact that the characterization of the transmit and receive path is not accurate enough. Solar interferences during the operational scanning are used to characterize the receiver. There, the bias found is small, about 0.2 dB, so that bias based on the comparison of the radar with external sensors is attributed to the transmit path. The representativeness of the disdrometer measurements are assessed using two additional disdrometers located within 200-m distance.

Item URL in elib:https://elib.dlr.de/111502/
Document Type:Article
Title:Monitoring the absolute calibration of a polarimetric weather radar
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Frech, MichaelDWD, HohenpeissenbergUNSPECIFIED
Hagen, MartinDLR, IPAUNSPECIFIED
Mammen, TheodorDWD, HamburgUNSPECIFIED
Date:March 2017
Journal or Publication Title:Journal of Atmospheric and Oceanic Technology
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:34
DOI :10.1175/JTECH-D-16-0076.1
Page Range:pp. 599-615
Publisher:American Meteorological Society
ISSN:0739-0572
Status:Published
Keywords:Wetterradar, Kalibrierung, Monitoring
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Erdbeobachtung
DLR - Research theme (Project):R - Vorhaben Atmosphären- und Klimaforschung
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Lidar
Deposited By: Hagen, Dr.rer.nat. Martin
Deposited On:14 Mar 2017 12:44
Last Modified:31 Jul 2019 20:08

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