Measuring Across Large Areas and at Depth
To address this gap, environmental hydrologist Prof. Dr. Sascha Oswald of the University of Potsdam, working with the Helmholtz Centre for Environmental Research in Leipzig (UFZ), has launched the “Brandenburg Soil Moisture Network.” For the first time, the network will collect large-scale data on soil moisture across the state. The project uses a method called “Cosmic-Ray Neutron Sensing,” in which above-ground stations gather data across broad areas of the landscape. The method relies on cosmic rays from space striking the Earth and generating neutron radiation as they interact with the atmosphere. Depending on how much water is present in the soil—or snow—the radiation is reflected differently at the land’s surface. “What makes this method special is that we measure average soil moisture about 30 centimeters below the surface, where most roots are found. We can also use these measurements to estimate how much seepage water is moving downward,” Prof. Oswald explains. “And a single above-ground probe can do this for an area of ten hectares!” This makes the method far more effective than using satellite images and remote sensing to measure soil water storage.
An Extensive Network
The project is supported by the Brandenburg State Office for Mining, Geology, and Raw Materials, the State Environmental Agency, and the Ministry of Agriculture, Environment, and Climate Protection. The network now includes twelve stations distributed across the state, allowing researchers to develop representative findings. Prof. Oswald’s team also operates a cluster of 16 probes at a test site near Potsdam. This allows the researchers to collect detailed information about an area spanning several square kilometers.
The monitoring network is becoming increasingly comprehensive. Through a partnership with a private railroad company, five locomotives have been fitted with mobile probes that measure soil moisture along the tracks on every trip. Hydrologists are still working to combine data from the mobile monitoring stations with data from the stationary ones. If successful, the effort will produce a more comprehensive map of soil moisture across the state.
“After our research group and the UFZ have completed the initial processing, the collected data will also be made available to state agencies,” Oswald says. “They will then be able to compare landscape water-balance simulations with on-site measurements, making it easier to assess periods of drought.” The longer the network collects data, the more valuable it is likely to become, the hydrologist explains. “In the long term, we want to connect the multi-year data series with models of Brandenburg’s water balance.”
Prof. Dr. Sascha Oswald is a Professor of Subsurface Hydrology at the Institute of Environmental Science and Geography at the University of Potsdam.
This article was originally published in Portal - Zwei 2026 „Wasser“, the University of Potsdam magazine.