The GROW Observatory is the first continental-scale citizen science project to monitor soil moisture over an extended period and at unprecedented spatial density. Through GROW, thousands of citizens from 13 European countries have come together creating an unprecedented network of more than 6,000 low-cost soil sensors. Here (https://www.youtube.com/watch?v=gRkFnRo-WZg&feature=youtu.be) you can see a short movie that will give you more insights in the project objectives and results.

The GEO Department of TU Wien carried out an extensive evaluation of the low-cost sensor performances against lab measurements and professional probes. For more details check our recently published article: doi.org/10.5194/gi-9-117-2020. Furthermore, in-situ measurements collected by GROWers (only a subset, though) have also been included in the International Soil Moisture Network (ISMN). Have a look at https://geo.tuwien.ac.at/insitu/data_viewer/ if you want to download this dataset, e.g., for your own satellite validation analysis.

The above mentioned subset consists of 150 stations, located in the UK, Ireland, the Netherlands, Austria, Hungary and Greece. Each station measures surface soil moisture (0.0m - 0.1m) and air temperature using low-cost sensors. Observations are available from 08.02.2017 until 08.10.2019.

For more information have a look at our forum (GROW). There you will also find a figure that is one of the project's outputs and represents a soil moisture map based on interpolation of the in-situ sensors.

We would like to thank Drew Hemment, Mel Woods, and everyone involved within GROW for collecting and sharing the data with the ISMN.