New Soil Property Database Improves Oklahoma Mesonet Soil Moisture Estimates*

Abstract

Soil moisture data from the Oklahoma Mesonet are widely used in research efforts spanning many disciplines within Earth sciences. These soil moisture estimates are derived by translating measurements of matric potential into volumetric water content through site- and depth-specific water retention curves. The objective of this research was to increase the accuracy of the Oklahoma Mesonet soil moisture data through improved estimates of the water retention curve parameters. A comprehensive field sampling and laboratory measurement effort was conducted that resulted in new measurements of the percent of sand, silt, and clay; bulk density; and volumetric water content at −33 and −1500 kPa. These inputs were provided to the Rosetta pedotransfer function, and parameters for the water retention curve and hydraulic conductivity functions were obtained. The resulting soil property database, MesoSoil, includes 13 soil physical properties for 545 individual soil layers across 117 Oklahoma Mesonet sites. The root-mean-square difference (RMSD) between the resulting soil moisture estimates and those obtained by direct sampling was reduced from 0.078 to 0.053 cm3 cm−3 by use of the new water retention curve parameters, a 32% improvement. A >0.15 cm3 cm−3 high bias on the dry end was also largely eliminated by using the new parameters. Reanalysis of prior studies that used Oklahoma Mesonet soil moisture data may be warranted given these improvements. No other large-scale soil moisture monitoring network has a comparable published soil property database or has undergone such comprehensive in situ validation.

Soil moisture–precipitation coupling: observations from the Oklahoma Mesonet and underlying physical mechanisms

“…Campbell Scientific 229-L heat dissipation sensors are deployed at four depths (5, 25, 60, 75 cm) in the soil column and measure matric potential, from which volumetric water content is derived. Mesonet soil moisture observation error is low (Scott et al, 2013), and station density in Oklahoma is among the highest in North America. Daily (09:00 LST) measurements are used to characterize soil moisture conditions on the morning of each convective event.…”

Soil Moisture Affects Growing-Season Wildfire Size in the Southern Great Plains

“…Volumetric water content was then calculated from soil matric potential using van Genuchten parameters obtained from the Rosetta pedotransfer function. The necessary parameters were derived from soil water retention properties measured on soil samples collected at each Mesonet station location (Scott et al, 2013). Reference temperature difference data are available at the Oklahoma Mesonet Daily Data Retrieval webpage https://www.mesonet.org/index.php/ weather/daily_data_retrieval subject to the Oklahoma Mesonet Data Access Policy (verified 14 Oct. 2015).…”

Does Afternoon Precipitation Occur Preferentially over Dry or Wet Soils in Oklahoma?

“…This study utilizes in situ volumetric water content (cm 3 cm 23 ) from 113 Oklahoma Mesonet stations (Fig. Physical soil moisture properties were recently updated at each Oklahoma Mesonet site, and soil moisture observations from the Campbell 229-L sensors were evaluated with gravimetric samples (Scott et al 2013). Volumetric water content of the soil is estimated using the thermal matric potential that is measured by Campbell 229-L heat dissipation sensors at 5, 25, and 60 cm.…”

“…1). Root-mean-square difference between direct measurements of volumetric water content and those reported by the 229-L sensors varied from 0.08 to 0.05 cm 3 cm 23 , with an overall network average of 0.05 cm 3 cm 23 (Scott et al 2013). Physical soil moisture properties were recently updated at each Oklahoma Mesonet site, and soil moisture observations from the Campbell 229-L sensors were evaluated with gravimetric samples (Scott et al 2013).…”