Features Tel4Rain

Tel4Rain develops non-traditional rainfall monitoring capability based on opportunistic sensing that employs commercial microwave links (CMLs) from cellular telecommunication networks. It has several noteworthy advantages:

• Opportunistic sensing – utilizes existing infrastructure (low-cost), which is widely available
• High temporal and spatial resolution
• Near-surface observations – provides information about rainfall, which actually reaches the surface
• Continuous maintenance determined by the needs of primary purpose (telecommunications)
• Continual real-time data acquisition from a single location (network operation centre)

CMLs typically measure rainfall intensity several tens of meters above ground, use frequencies ranging from ∼6 to 80 GHz, and have path lengths varying from ~0.1 to ~20 km. CML network has usually highest density in urban areas. Urban CML networks typically consist of CMLs with path lengths of a few km operating at higher frequencies (20-80 GHz) which are more sensitive to rainfall.

From the decrease in signal level along the CML path, the rainfall-induced path-averaged specific attenuation can be calculated, which can be converted to a path-averaged rainfall intensity by employing the above power-law. Subsequently, the obtained path-averaged rainfall intensities from individual CMLs can be utilized to create high-resolution rainfall maps.

Required CML data and metadata:

• Transmitted signal level (TSL) and Received signal level (RSL) for each CML for each time interval
• Date and time of observation
• Frequency of a CML
• Signal polarisation
• Coordinates of the start and the end of the CML, and a unique CML identifier

Tel4Rain specific features:

• CML data acquisition every 10 seconds – minimizing errors from averaging instantaneous values
• Data from a large number of CMLs – minimizing errors due to spatial averaging
• Algorithms for CML signal attenuation conversion into rainfall intensities validated in multiple pilot projects – using raingauge data
• Interdisciplinary team and collaboration with data providers and end-users

Applications and Benefits:

• Urban hydrology – timely preditions of flash floods (high temporal and spatial resolution of rainfall data is essential)
• Optimization of urban drainage and sewage system management and optimization of wastewater treatment plant processes
• Correction of weather radar precipitation products – improvement of hydrological predictions as well as past event analysis