Pludix is an X-band disdrometer based on the Doppler principle, providing information on the drop size spectra and the rainfall intensity. This work describes the research done to determine the capabilities and limitations of Pludix also as a Present Weather Sensor (PWS). Twelve precipitation codes have been selected. The Pludix precipitation codes are considered by comparing with the characteristics of the power spectrum, the maximum intensity and its position in the frequency range. The precipitation types corresponding to the twelve codes are: rain, snow, hail, ice crystals, mixed precipitation. Pludix is compared with the reference observations of a human observer during a campaign performed at the weather station Wasserkuppe, located in central Germany at an elevation of 950 m (asl). Two years of data are analysed (from December 2000 to January 2003); in this time interval, there was a fair amount of both liquid and solid precipitation, allowing for a good evaluation of the instrument capabilities. All data are synchronized in 1-minute time intervals, leading to a maximum of 1440 measurements per day. The (human) observed precipitation type, reported in WMO code 4677, is changed into code 4680 (automatic observation) to match with the output of our instrument. The results show that Pludix performs quite well in distinguishing precipitation type and it is generally in agreement with the human observations. It is also found that our instrument detects some situations (especially rain-shower with hail; ice crystals) that the human observer does not detect. Moreover Pludix is compared with other PW instruments: the Vaisala FD12P-PWS (V1.83 1999-11-19, SN: 30301) and the optical disdrometer Parsivel M300 (PMTech). The Parsivel M300 used in this intercomparison has been produced by PMTech company (Germany) and it is no longer on the market. The instrument has been completely redesigned in hardware and software and it is now produced by OTT company (Germany) under the name “OTT Parsivel”. We also test the performance of Pludix in measuring the rainfall-intensity, comparing it with the other sensors for some significant events. Finally, some drop size spectra analysis for Pludix and the optical disdrometer Parsivel are shown.
Precipitation type and rainfall intensity from the Pludix disdrometer during the Wasserkuppe campaign.
CARACCIOLO, Clelia;PRODI, Franco;
2008
Abstract
Pludix is an X-band disdrometer based on the Doppler principle, providing information on the drop size spectra and the rainfall intensity. This work describes the research done to determine the capabilities and limitations of Pludix also as a Present Weather Sensor (PWS). Twelve precipitation codes have been selected. The Pludix precipitation codes are considered by comparing with the characteristics of the power spectrum, the maximum intensity and its position in the frequency range. The precipitation types corresponding to the twelve codes are: rain, snow, hail, ice crystals, mixed precipitation. Pludix is compared with the reference observations of a human observer during a campaign performed at the weather station Wasserkuppe, located in central Germany at an elevation of 950 m (asl). Two years of data are analysed (from December 2000 to January 2003); in this time interval, there was a fair amount of both liquid and solid precipitation, allowing for a good evaluation of the instrument capabilities. All data are synchronized in 1-minute time intervals, leading to a maximum of 1440 measurements per day. The (human) observed precipitation type, reported in WMO code 4677, is changed into code 4680 (automatic observation) to match with the output of our instrument. The results show that Pludix performs quite well in distinguishing precipitation type and it is generally in agreement with the human observations. It is also found that our instrument detects some situations (especially rain-shower with hail; ice crystals) that the human observer does not detect. Moreover Pludix is compared with other PW instruments: the Vaisala FD12P-PWS (V1.83 1999-11-19, SN: 30301) and the optical disdrometer Parsivel M300 (PMTech). The Parsivel M300 used in this intercomparison has been produced by PMTech company (Germany) and it is no longer on the market. The instrument has been completely redesigned in hardware and software and it is now produced by OTT company (Germany) under the name “OTT Parsivel”. We also test the performance of Pludix in measuring the rainfall-intensity, comparing it with the other sensors for some significant events. Finally, some drop size spectra analysis for Pludix and the optical disdrometer Parsivel are shown.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
