Soil Moisture. 5.1. Data collection methods The soil moisture monitoring under the 1995 Agreement continued in 2019 on the Slovak and Hungarian Territories in accordance with the approved monitoring optimization. The Slovak Party performs the soil moisture measurements using a neutron probe on 13 monitoring sites, all of which are located in the inundation. Measurements are performed at 10 cm depth intervals down to the groundwater level. The monitoring of soil moisture on the Hungarian side was interrupted in the years 2013 to 2017. Since 2018, the monitoring has continued on 12 localities, 6 of which are located in the agricultural area. Most of monitoring sites on the Hungarian side needed to be restored or rebuilt, so the soil moisture monitoring was introduced gradually during 2018. Also on the Hungarian side, the monitoring is carried out according to the existing methodology, thus by the capacitive probe, in 10 cm depth intervals to a maximum depth of 3 m or to the groundwater level. The Hungarian Party at some sites has also installed devices for continuous recording of soil moisture changes of the Xxxxxxxx CS616 type. At these localities, measurements with the capacitive probe will be carried out at the same time. On both sides, the measured values of soil moisture are expressed by the total soil moisture content in volume percentage. The list of monitoring sites are given in Tables 5-1 and 5-2 and their situation is shown in Fig. 5-1.
Soil Moisture. The soil moisture is a product of the Soil Moisture and Ocean Salinity (SMOS) mission of the European Space Agency (ESA) obtained from the instrument MIRAS. Data availability is assured through the ground segment CATDS (Centre Aval de Traitement des Données SMOS) operated for the "Centre National d'Etudes Spatiales" (CNES, France) by IFREMER (Brest, France). The data are currently derived from level 3 monthly averaged products. The monthly resolution is obtained from aggregated daily global maps, whose number can vary from month to month.
Soil Moisture. The target of the SMOS mission is to provide a global image of soil moisture every one to three days with an accuracy of 4 % at a spatial resolution of 50 km. The unit is m³/ m³. As the original data has a different coordinate reference system (EASE-Grid, EPSG:6933) than used for this project, a transformation to UTM WGS84 has been performed. This data set was clipped according to the study areas and resampled to the 100 m grid, resulting in monthly SMOS data for the year 2014 for each study area. For the estimation of the accuracy, it is relevant to note that the number of daily maps included in the monthly average varies, depending on the satellite cover. However, there was no information available on these coverages.
