MicroWeather

What do you see in the picture?

This is a visualisation to demonstrate the concept of monitoring rainfall using microwave links in telecommunication networks (MicroWeather).

The coloured areas on the map show where it rained and how much rainfall was observed in central Gothenburg, Sweden for a specific rainfall event.

Please note that this is a prototype, and as such may be missing data or show erroneous information at times. For example, coloured pixels may appear even if it did not rain due to non-rain signal distortions. Coloured areas that do not move is an indication of such noise.

Using microwave links to monitor rainfall

Microwave links constitute an important part of the backhaul network in telecommunication networks. The microwave links essentially transmit a microwave signal between two telecommunication tower locations through the lower atmosphere. Rainfall attenuates the signal, and the attenuation is proportional to rainfall intensity. This provides an opportunity to monitor rainfall using such networks (here termed MicroWeather).

MicroWeather at SMHI

The activities of the Swedish Meteorological and Hydrological Institute (SMHI) on MicroWeather begun in 2015 through a joint pilot project with Ericsson and Hi3G Sweden. The Hi3G commercial microwave link network in and around Gothenburg, Sweden has been monitored ever since and used to derive rainfall intensity at 1-minute resolution based on raw signal strength data sampled at 10-second resolution from more than 350 bi-directional links covering an area of about 4000 km2. Based on spatial interpolation of the data from each link, rainfall intensity maps are constructed for central Gothenburg at 500x500m resolution, which is visualized above.

What are the results?

The results of the pilot project indicate that the microwave links provide several advantages compared to conventional rainfall monitoring systems (e.g. weather radar and gauges), including:

more complete spatial coverage (350 links vs. 11 operational gauges in Gothenburg),
higher temporal resolution (1-min for links vs. 15-min for SMHI’s operational gauges and radar),
higher spatial resolution (primarily in urban areas, 0.25km2 for links vs. 4km2 for SMHI’s operational radar),
near-ground sampling (weather radars have a risk of missing precipitation from low clouds or measure precipitation that evaporates before reaching the ground),
high-frequency sampling (every 10s, avoiding that a quick event is missed which can happen for e.g. 15-min sampling by radar),
and more accurate representation of temporal dynamics and peak rainfall intensities.

References

Andersson et al. 2017, Microwave Links Improve Operational Rainfall Monitoring in Gothenburg, Sweden. 15th International Conference on Environmental Science and Technology, 31st August – 2nd September 2017, Rhodes, Greece. Conference paper CEST2017_00249 in the CEST2017 Proceedings:

Microwave Links Improve Operational Rainfall Monitoring in Gothenburg, Sweden (PDF)

Microwave link network and precipitation gauges in Gothenburg, Sweden.

MicroWeather map

Radar image with lightning strikes

Composite radar images are generated with data from as many available weather radars as possible. All together, there are 12 weather radars in Sweden.

Contact

In Swedish