Præsentation af Aalborg Universitet 1 af 24 UWT seminar 2010 Jesper Ellerbæk Nielsen ”Combining C-band and X-band weather radars for accurate precipitation measurements over urban areas” Supervisors: Michael R. Rasmussen (AAU) Rasphal Gill (DMI) Niels Ejner Jensen (DHI)

Præsentation af Aalborg Universitet 2 af 24 SWI – Storm and Wastewater Informatics

Præsentation af Aalborg Universitet 3 af 24 SWI – Storm and Wastewater Informatics The PhD project is located within WP2 Aalborg University DMI DHI 2 PhD 2 Post Doc WP 1 WP 3WP 2WP 4 WP 5

Præsentation af Aalborg Universitet 4 af 24 SWI – Storm and Wastewater Informtic The purpose of the project is to improve the overall data quality of weather radar precipitation measurements. WP 1 WP 3WP 2WP 4 WP 5

Præsentation af Aalborg Universitet 5 af 24 Weather radar measurements How does the weather radar work? Its all about timing! It measures the electromagnetic waves reflected by the precipitation Indirect measurement of precipitation

Præsentation af Aalborg Universitet 6 af 24 The traditional tipping bucked rain gauge

Præsentation af Aalborg Universitet 7 af 24 Tipping bucked rain gauges - Rimco The tipping bucked rain gauge is measuring the weight of the water. Read Contact Tipping bucked Outlet Bubble level

Præsentation af Aalborg Universitet 8 af 24 C-band and X-band radars C-Band radar operated by DMI LAWR X-Band radar developed by DMI

Præsentation af Aalborg Universitet 9 af 24 Weathers in Denmark C-band Radars, range 240 km Danish Metrological Institute (DMI) 2000 x 2000 m spatial resolution 10 min. temporal resolution Marine X-band Radars, range 60 km Developed by DHI 500 x 500 m, 100 x 100 m spatial resolution, 5 min. temporal resolution X-bånd (Århus) X-bånd (Aalborg) X-bånd (Hvidovre) X-Bånd (Hørsholm) X-bånd (Odense) X-bånd (Vejle) X-bånd (Egedal)

Præsentation af Aalborg Universitet 10 af 24 2 x 2 km (C-Band) Kilde: COWI A/S og Aalborg kommune Spatial resolution

Præsentation af Aalborg Universitet 11 af 24 Kilde: COWI A/S og Aalborg kommune 100 x 100 m (LAWR X-Band) Spatial resolution

Præsentation af Aalborg Universitet 12 af 24 But why all these radars? – Hypothesis for the project It is possible to combine X-band radars with C-band weather radars, so that the combination outperforms the individual radar. Strategy: Strengths of one radar type can compensate the other radar types weaknesses. Range Resolution Atmospheric attenuation Ground clutter

Præsentation af Aalborg Universitet 13 af 24

Præsentation af Aalborg Universitet 14 af 24 Exampel18/ C-bandX-band

Præsentation af Aalborg Universitet 15 af 24 Challenges in combination of radar data What is detected by the radar, and how is the atmosphere integrated?

Præsentation af Aalborg Universitet 16 af 24 Vertikal scanning radar Based on a Furuno 1715 X-band marine radar a highly flexible radar has been develobed The purpose of the radar is by profiling the precipitation it will reveal what the individual radar detects.

Præsentation af Aalborg Universitet 17 af 24 Micro Radar Test Bed Stepper motor controlling the direction Analog - Digital converter Laptop managing the stream of data and the direction of the antenna Furuno 1715 antenna Furuno 1715 display unit

Præsentation af Aalborg Universitet 18 af 24

Præsentation af Aalborg Universitet 19 af 24 Laser based distrometer – OTT Parsivel Describing the precipitation by drop size and drop velocity

Præsentation af Aalborg Universitet 20 af 24 Laser based distrometer – OTT Parsivel

Præsentation af Aalborg Universitet 21 af 24 Strategy for combination Spectral analysis: Break down the radar images into its spectral components Use the components as building bricks in rebuild of a single result with properties of both radars

Præsentation af Aalborg Universitet 22 af 24