Scatterplot of GPS versus in situ snow depth for all three years at the
alpine site (NWOT). A simple linear regression is shown in red, with its 95%
observation prediction interval shown as a light-gray band. Postfit residuals
(with respect to the red line) are shown in the middle panel; the bottom panel
shows residuals normalized by the in situ snow depth value. The ideal 1:1
diagonal is shown as a dotted black line for comparison.