From SwissExperiment

X-Band Precipitation Radars

SwissEx has access to two X-Band precipitation radars which are to be integrated into the data infrastructure and deployed in the main inderdisciplinary deployments.

Contents 1 X-Band Precipitation Radars 1.1 Mobile X-Band Radar 1.1.1 Background 1.1.2 Aims 1.1.3 Technical Specifications 1.1.4 Real-Time Data 1.2 Fixed X-Band Radar 1.2.1 Aims 1.2.2 Technical Specifications 1.2.3 Real-time data 1.2.4 Additional information

Mobile X-Band Radar

The EPFL laboratory for environmental remote sensing (LTE) have acquired a state-of-the-art mobile X-Band precipitation radar, the aim of which is to improve measurement of the precipitation in mountainous regions (see aims). A measurement campaign is currently taking place in collaboration with WSL, Institute for Snow and Avalanche Research, SLF, and will remain from summer 2009 until spring 2010. The radar is installed opposite the Wannengrat mountain observatory on Ischalp, Jakobshorn and is supplemented by ground based precipitation sensors around the Davos area.

Background

The Swiss meteo service (MeteoSwiss) maintain three fixed precipitation radars in Switzerland. The data from these radars are used in weather forecasting, but are also valuable in producing hazard warnings (storms, floods etc.) and for hydrological research. In the alpine landscape, the data from these radars is somewhat unreliable as the mountains impair the view of the radar. Snowfall also provides radar returns which are very difficult to interpret, often meaning that inaccurate measurements are produced. Recent technology has however provided solutions which allow some of these problems to be overcome as well as providing additional information on the type of precipitation.

Aims

• To gain experience in collecting and interpreting data with the newest generation of precipitation radars.
• Improving the measurement of the amount of precipitation in mountainous areas.
• Investigation of the small scale structure of precipitation
• Identification of the various types of snow. This information will lead to an improved understanding of the development of the snowpack and could lead to improved avalanche prediction in future.

Technical Specifications

The technical specifications for the radar are detailed below. A licence for the operation of this radar has been granted by the Swiss Federal Office for Communication (BAKOM) for use in the area of Davos.

• Manufacturer: ProSensing, Amherst, MA
• Frequency: ~9GHz
• Beamwidth (3dB): 1.5^o
• Polarisation: horizontal and vertical simultaneously
• Principle: Coherent Doppler

Real-Time Data

Click here for animations of data collected in Davos.

Contact: Alexis Berne.

Fixed X-Band Radar

The cost-effective fixed X-band weather radar used in this project was adapted by the Danish Hydraulic Institute from maritime applications to precipitation detection. It is commonly called LAWR (Local Area Weather Radar). This LAWR has been installed thanks to collaboration between the Institute of Environmental Engineering (ETHZ) and the canton of Valais. It is located on the summit of the Klein Matterhorn (3,883m a.s.l.).

Aims

• Investigation of the space-time variability of precipitation in orographically complex regions
• Creation of multi-source merged precipitation estimation (together with MeteoSwiss radars and the X-band mobile radar)
• Definition of new statistical method to compare radar measurements

Technical Specifications

The technical specifications for the radar are detailed below.

• The measurement principle: emission/reception of electromagnetic waves: X-band, 3.2cm wavelength at 9.4GHz
• 25KW peak power
• Fan-beam antenna, beam height = +/-10°, beam width = 0.95°
• Maximum range: 60km
• Resolution: from 500 to 100m in space and up to 1 min in time

The estimation of the precipitation is ground-truth based. The ground observations are given by a dedicated sensor network made of 6 weighing (MPS) raingauges and 13 tipping-bucket (SensorScope) raingauges in addition to the MeteoSwiss ANETZ network.

Real-time data

Real-time data can be viewed here.

Additional information

Additional information: Homepage of the HWRM-Radar

Contact: Maurizio Savina