Spatial variability of surface temperature along two transects of a bare soil

The spatial variability of surface temperature has been examined on a bare soil located at the University of California at Davis. Surface temperatures were measured between 1300–1400 hours three consecutive days after a sprinkler irrigation. Measurements were made at every meter along two transects with two infrared thermometers differing only by their field of view. In addition, soil samples were collected on the third day with the same pattern to determine the gravimetric water content between the soil surface and 5 cm of depth. All data were found to be normally distributed regardless of their position along the transects. Semivariograms and autocorrelation functions were determined and the measurements were found to be correlated over space. A first‐order autoregressive process with a white noise was found to describe the spatial structure of all the sets of data. Variances of sample means were calculated by taking into account the interdependence between observations and were compared to variances obtained by assuming uncorrelated observations.