Soil Sampling for Calibration of Cosmic Ray Soil Moisture Sensor, Tumbarumba Wet Eucalypt SuperSite, 2012

Soil sampling was carried out 26 Apr 2012 to calibrate the Cosmic-ray Soil Moisture Observation sensor. A cosmic ray soil moisture sensor was installed at the Tumbarumba Wet Eucalypt Supersite on 03 Apr 2011 by the Australian Cosmic Ray Soil Moisture Monitoring Network (CosmOz; http://www.ermt.csiro.au/html/cosmoz.html). CosmOz sensors use cosmic rays originating from outer space to measure average soil moisture over an area of about 40 hectares to a depths of between 10cm in wet soils to 70cm in dry soils. The system measures fast neutrons that are produced from interactions of cosmic rays with the atmosphere and top few meters of soil. The intensity of these neutrons are moderated largely by water molecules in the soil. The number of neutrons counted over a period of time is inversely proportional to the amount of water in the soil. To estimate volumetric water content, each system is calibrated against soil samples that are collected from dry and wet moisture regimes using a standard protocol. Tumbarumba Supersite land cover: Wet sclerophyll eucalyptus forest, Land use: native/plantation forestry, Soil type: Acidic, eutrophic red dermosol, 3 - 4 m deep Tumbarumba soil calibration data can be downloaded from http://cosmos.hwr.arizona.edu/Probes/StationDat/077/calib.php