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Soil moisture is an important component in many hydrologic and land–atmosphere interactions. Understanding the spatial and temporal nature of soil moisture on the mesoscale is vital to determine the influence that land surface processes have on the atmosphere. Recognizing the need for improved in situ soil moisture measurements, the Oklahoma Mesonet, an automated network of 116 remote meteorological stations across Oklahoma, installed Campbell Scientific 229-L devices to measure soil moisture conditions. Herein, background information on the soil moisture measurements, the technical design of the soil moisture network embedded within the Oklahoma Mesonet, and the quality assurance (QA) techniques applied to the observations are provided. This project also demonstrated the importance of operational QA regarding the data collected, whereby the percentage of observations that passed the QA procedures increased significantly once daily QA was applied. [ABSTRACT FROM AUTHOR]

Established as a multipurpose network, the Oklahoma Mesonet operates more than 110 surface observing stations that send data every 5 min to an operations center for data quality assurance, product generation, and dissemination. Quality-assured data are available within 5 min of the observation time. Since 1994, the Oklahoma Mesonet has collected 3.5 billion weather and soil observations and produced millions of decision-making products for its customers. [ABSTRACT FROM AUTHOR]

In 1999, the Oklahoma Mesonet deployed infrared temperature (IRT) sensors at 89 of its environmental monitoring stations. A 3-yr dataset collected since that time provides a unique opportunity to analyze longer-term, continuous, mesoscale observations of skin temperature across a large area. Several limitations of the sensor have been identified and include 1) failure of the calibration equation during the cold season, 2) difficulty in keeping the sensor's lens clean at remote sites, and 3) limited representativeness of local conditions due to the sensor's narrow field of view. Despite these limitations, the Oklahoma Mesonet's skin temperature network provides a wealth of information that can be used to better understand many land–atmosphere interactions. Not only can the observations be used to estimate the partitioning of latent and sensible heat flux, they also provide beneficial “ground truth” estimates to validate remotely sensed estimates of skin temperature. This manuscript describes the IRT sensor, evaluates its performance, and provides analysis of time series data and observed spatial variability across Oklahoma. [ABSTRACT FROM AUTHOR]

The Oklahoma Mesonet, an automated network of 115 meteorological observing stations, includes soil moisture monitoring devices at 60 locations. The Campbell Scientific model 229-L matric potential (water potential) sensor was chosen for operational use based on its capability to perform as a fully automated soil water measuring device. Extensive laboratory calibrations were performed on each sensor to ensure the quality of the matric potential measurements. Examination of the data from the Norman site during July 1997 revealed significant inconsistencies between near-surface (5 and 25 cm) measurements of soil moisture and deep-layer (60 and 75 cm) measurements of soil moisture. In particular, a heavy precipitation event was followed by only a small increase in near-surface soil water potential values, while a much larger increase occurred in the deep-layer values. It is theorized that an installation flaw is the cause for these inconsistencies. A solution is proposed in the hope that future efforts to measure soil moisture will not be hindered by similar problems. [ABSTRACT FROM AUTHOR]