Radar rain gauges new alternative for urban measurement networks. Copyright OTT Hydromet 2018

Transcription

1 Radar rain gauges new alternative for urban measurement networks

2 Stormwater event in the city of Münster July 28 th Ernst Mennerich

3 Stormwater event in the city of Münster July 28 th Ernst Mennerich

4 6 Di.,

5 City of Wuppertal 28. July Di., Foto: Privat

6 City of Wuppertal 28. July

7 City of Wuppertal 28. July Mo., Foto: Matthias Ahlke

8 City of Wuppertal 28. July

9 Micro retention! 11 Di., Foto: mfk

10 12

11 Stormwater event in the city of Münster July 28 th 2014 ~150 mm/12hrs ~292 mm Online-Calibration 13

12 Stormwater event in the city of Münster July 28 th ,53 mm within 8 hrs Pluvio² L 14

13 Stormwater event in the city of Münster July 28 th 2014 ~150 mm/12hrs 292,53 mm Online-Calibration Offline-Calibration 15

14 Overview of Different Measurement Principles Tipping Bucket Weighing Gauge Radar Disdrometer 16 Confidential and Proprietary

15 Tipping bucket Pro s: Con s: Standard in many applications Low price Medium accuracy High Maintenance required!!! Lower accuracy in low and high ranges Even more inaccurate during winter operation 17

16 OTT Pluvio² - Weighing system Pro s Con s No moving parts Low maintenance (1 2 per year) Most accurate measurement of liquid and solid precipitation due to weighing principle Proven in WMO intercomparison test 15,000 units deployed in countries of Northern Hemisphere Higher investment necessary Sometimes form factor Pluvio² L Bucket 1500 mm Highly accurate weighing system 18

17 OTT Parsivel² - Laser-based optical system Laser-based optical system Parsivel² for simultaneous measurement of Particle Size and Velocity in precipitation The sensor's transmitter unit generates a flat, horizontal beam of light, which the receiver unit converts into an electric signal. This signal changes whenever a particle falls through the beam anywhere within the measurement area The degree of dimming is a measure of the particles size, and together with duration of the signal, the fall velocity can be derived. 19

18 OTT Parsivel² - Laser-based optical system Drop Spectrum 20

19 OTT Parsivel² Weather Radar Drop size distribution data Radar reflectivity Z/R Real-time Disdrometer solution 21

20 OTT Parsivel² - Laser-based optical system Pro s Con s Not only intensity, but type of precipitation High accuracy (type of precipitation) Delivers parameter for weather radar optimization Less accurate than a Pluvio (intensity of precipitation) Parsivel² 22

21 New Precipitation sensor WS100 WS100 24GHz Doppler Radar precipitation sensor with disdrometer functionality 23

22 Overview - WS100-UMB Measuring Principle 24 GHz Microwave Doppler Radar works with the radar reflection method and measures the precipitation quantity or precipitation intensity by means of the correlation of drop size and velocity. Drop Size distribution matrix to calculate intensity of precipitation and to determine type of precipitation according fundamental meteorological relationships Rain Snow WS100 24

23 Overview - WS100-UMB Measuring Principle Pro s: Maintenance-free operation Precipitation type detection (rain, snow, sleet, freezing rain, hail) Extremely fast measurement (first drop detected) Dome heating available Cost efficient Con s: Lower Accuracy liquid: +/- 10 % Solid: +/- 30 % WS100 28

24 When to use what? Tipping bucket if man power for maintenance is available Weighing principle if highest accuracy (intensitiy) and low maintenance is required for statistical analysis Disdrometer if type of precipitation is required for improvement of weather radars Radar if no maintenance is required if consolidation of network is required if accuracy is not so important 31

25 Thank you very much for your attention! 32