Upscaling of point soil moisture measurements to field averages at the OPE3 test site

SummarySome techniques are proposed to limit the representativeness error of point soil moisture observations as estimates for spatial mean soil moisture in the Optimizing Production Inputs for Economic and Environmental Enhancement (OPE3) field site. First, representative measurement locations for the spatial mean soil moisture are sought by ranking of the sensors based on the time–mean differences between the point values and the spatial mean. Next, simple statistical methods, as well as models in both the time and frequency domain are explored to scale up point measurements to field averaged soil moisture. Upscaling by a simple linear relationship and cumulative distribution function (cdf) matching generally provide the best estimates of the temporal evolution of the spatial mean soil moisture.