The Oklahoma Mesonet’s soil moisture network began as a research initiative funded by the National Science Foundation’s (NSF) Experimental Program to Stimulate Competitive Research (NSF-EPSCoR) in 1995. Operational since 1997, the network was later augmented by the Oklahoma Atmospheric Surface-layer Instrumentation System (OASIS). The usefulness of the Mesonet’s soil moisture data network to decision-makers was realized during the drought-affected summers of 1998 and 2000, and was reinforced through the extended dry spell of 2001.

The Oklahoma Mesonet has a total of 332 soil moisture sensors deployed at 102 mesonet sites. Sensors are placed at 5, 25, 60, and 75cm depths. The sensors report soil moisture data every 30 minutes, 24 hours each day, totaling over 380,000 reports per day. The challenge was to not only produce the data in a viable format for meteorological researchers, but also in a format friendly to Oklahoma decision-makers. Each datum undergoes a rigorous quality assurance regimen, testing the physical limits of the sensors. The arduous task of quality assuring and disseminating 140 million soil moisture reports per year is complicated by the desire of both user communities - research and policy-making - to have the data tailored to fit their separate needs.

Historical archives and real-time Mesonet soil moisture data are provided to customers via a web-based interface. Quantities provided are soil temperature, matric potential, and volumetric water content. A statewide snapshot of soil moisture conditions also is provided and displays matric potential categorized as “dry”, “limited”, “adequate”, and “moist/wet”. This provides an expedient view of soil moisture to the policy-making and agricultural communities.

Oklahoma has experienced 3 significant dry events since the soil moisture network became operational. In each of those events, the Mesonet’s soil moisture data portrays the drying and subequent recharge of the soil layers over time. This ability to see the stratified soil moisture conditions beneath the surface is a key resource in determining both the genessis and demise of drought events.

One of the lessons we have learned, and perhaps the biggest challenge we face, is that the state of soil moisture knowledge is in continual flux. As the research community receives and analyzes the data, improvements are made upon the quality assurance and coefficients. In turn, these improvements require implementation into the dissemination process.