Germany-wide rainfall measurements by utilizing the mobile network


Date:
August 3, 2020
Source:
Karlsruher Institut fu"r Technologie (KIT)
Summary:
Whether in flood early-warning systems or in agriculture -
rainfall measurements are of great importance. However, there
is a lack of accurate data for many regions in the world due
to the fact that comprehensive measurements have so far been
too expensive. Researchers have now succeeded in utilizing the
commercial microwave link network operated by mobile network
providers for Germany-wide rainfall measurements.



FULL STORY ========================================================================== Whether in flood early-warning systems or in agriculture -- rainfall measurements are of great importance. However, there is a lack of accurate
data for many regions in the world due to the fact that comprehensive measurements have so far been too expensive. This could change with a
new method that has just passed its practical test. Researchers at KIT (Karlsruhe Institute of Technology) and the University of Augsburg
have succeeded in utilizing the commercial microwave link network
(CML) operated by mobile network providers for Germany-wide rainfall measurements. This new technology is now planned to be used in West
Africa. The team published their results in the scientific journals
Hydrology and Earth System Sciences and Atmospheric Measurement
Techniques.


==========================================================================
Rain can significantly impair the performance of a mobile network. But
a phenomenon that can cause headaches for telecommunications companies
is a stroke of luck for meteorological research: "We have developed a completely new method for rain measurement from this interaction between weather events and human technology," says Professor Harald Kunstmann
from the Institute of Meteorology and Climate Research -- Atmospheric Environmental Research (IMK- IFU), the so-called Campus Alpin of KIT. "If
a commercial microwave link network (CML) is in place, we neither need a
new infrastructure nor additional ground staff." Together with scientists
from the University of Augsburg, his KIT team now succeeded in performing
the first Germany-wide rainfall measurement with the new method: They were
able to derive rainfall maps with high temporal resolution based on the attenuation of the CMLs between several thousand of mobile phone masts
that is caused by precipitation. "A comparison with the measurements
of the German Meteorological Service shows that we have achieved a
high degree of correlation," explains Maximilian Graf, member of the
research team.

Improved accuracy thanks to artificial intelligence (AI) Precipitation
could be determined thanks to the CML antennas installed in mobile phone
masts for signal transmission over long distances. "A frequency of 15
to 40 gigahertz is used here. Its wavelength corresponds to the typical
size of raindrops," explains Dr. Christian Chwala who coordinates this
research work at the University of Augsburg. "Increasing precipitation
weakens the signal that radio masts use to exchange information. Over
one year, we measured the current attenuation obtained from 4,000 CMLs
with a temporal resolution of 1 minute. The resulting data set is unique
in its resolution and enormous size." Besides the classical methods
of data analysis, the researchers used artificial intelligence (AI)
to filter the rain signal from the noisy measurement results.

"Other factors, such as wind or the sun, can also cause a slight
attenuation of the signal. With the help of our AI, we were able to
identify the signal attenuation that was due to rainfall," says Julius
Polz, another scientist from the research group. "We have now trained
our AI in such a way that we no longer need to calibrate the system
using traditional methods of rain measurement." Thus, it is suitable
for application in regions without significant rainfall measurements
that could be considered for AI training, such as West Africa.

Planned use in West Africa For Germany, however, the method works mainly
in spring, summer, and fall.

"This is because sleet and freezing rain cause a higher attenuation than
liquid precipitation, and snow cannot be measured with the CML network
at all," explains Harald Kunstmann. Several projects are currently
underway where the researchers will measure rainfall using CMLs,
with one particular focus on Germany, in cooperation with the German Meteorological Service and the Office for the Environment of the state
of Saxony. In the course of the summer, further projects will start in
the Czech Republic and in Burkina Faso, where a nationwide collection
of CML data is to be established for the first time in Africa.


========================================================================== Story Source: Materials provided by
Karlsruher_Institut_fu"r_Technologie_(KIT). Note: Content may be edited
for style and length.


========================================================================== Journal References:
1. Julius Polz, Christian Chwala, Maximilian Graf, Harald
Kunstmann. Rain
event detection in commercial microwave link attenuation data using
convolutional neural networks. Atmospheric Measurement Techniques,
2020; 13 (7): 3835 DOI: 10.5194/amt-13-3835-2020
2. Maximilian Graf, Christian Chwala, Julius Polz, Harald Kunstmann.

Rainfall estimation from a German-wide commercial microwave
link network: optimized processing and validation for 1 year of
data. Hydrology and Earth System Sciences, 2020; 24 (6): 2931 DOI:
10.5194/hess-24-2931-2020 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200803120146.htm

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