Soil Moisture Content, Cosmic Ray Soil Moisture Sensor, Far North Queensland Rainforest SuperSite, Robson Creek, 2014

A cosmic ray soil moisture sensor was installed at Robson Creek node of the FNQ Rainforest Supersite on 28 Oct 2010 by the Australian Cosmic Ray Soil Moisture Monitoring Network (CosmOz; http://www.ermt.csiro.au/html/cosmoz.html). CosmOz represents just one of a growing number of networks around the World. Other networks are found in USA, Germany, and the UK with other projects adopting the technology in South America, Africa and Europe.

These sensors use cosmic rays originating from outer space to measure average soil moisture over an area of about 40 hectares to a depth up to 90 cm. 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.

Data is collected every 60 min and uploaded to data portal infrastructure which is maintained by the University of Arizona. This infrastructure and associated web interface were established as part of the US based Cosmic-ray Soil Moisture Observation System (COSMOS, http://cosmos.hwr.arizona.edu/). Collaboration between Australian and US researchers has facilitated a data hosting agreement which has now resulted in a growing international data portal for delivering and processing data from cosmic-ray probes.

The Robson Ck data can be downloaded from http://cosmos.hwr.arizona.edu/Probes/StationDat/073/index.php

2010年10月28日，澳大利亚宇宙射线土壤湿度监测网络（CosmOz；http://www.ermt.csiro.au/html/cosmoz.html）在FNQ雨林超级站点的罗布森溪节点安装了一台宇宙射线土壤湿度传感器。CosmOz仅是全球日益增多的同类监测网络之一，美国、德国、英国均已部署相关网络，南美、非洲与欧洲的诸多项目也已采用该探测技术。

此类传感器依托源自外太空的宇宙射线，可对面积约40公顷、最大探测深度达90厘米的区域内的平均土壤湿度进行定量监测。该系统通过探测宇宙射线与大气及表层数米土壤相互作用产生的快中子完成观测：中子强度主要受土壤内水分子的慢化调控，单位时段内计数的中子总数与土壤含水量呈反比关系。为准确估算体积含水量，每套系统均需依据标准规程，对取自干湿不同湿度状态的土壤样本开展校准工作。

数据采集间隔为60分钟，采集后将上传至由亚利桑那大学维护的数据门户基础设施。该基础设施及配套网页界面是美国宇宙射线土壤湿度观测系统（Cosmic-ray Soil Moisture Observation System，缩写COSMOS；http://cosmos.hwr.arizona.edu/）的组成部分。澳美两国研究人员的合作促成了数据托管协议，如今该协议已推动形成一个持续发展的国际数据门户，用于传输和处理来自宇宙射线探测仪的观测数据。

罗布森溪节点的观测数据可从以下链接下载：http://cosmos.hwr.arizona.edu/Probes/StationDat/073/index.php