BBAuthors: Bagnall, D.K.; Advisor: -; Participants: Gutierrez, P.M.C.; Yimam, Y,T.; Morgan, C.L.S.; Neely, H.L.; Ackerson, J.P. (2018)
After NMM measurements were taken in a tightly installed access tube, either a small or large annulus was installed in the same borehole. Additional NMM measurements were taken with the annulus filled with air, and then water and ρb and θv were measured. The RMSE of the NMM calibration using all 11 installations was 0.02 m3 m−3. However, if two cores were used for calibration, the ratio of NMM‐measured θv to in situ θv was significantly different (p < 0.05) from measured θv half the time (RMSE, 0.012–0.05 m3 m−3). Small air‐filled voids created drier estimates of θv (bias, −0.039 m3 m−3; p < 0.001), wherease small water‐filled voids were not significantly different from the calibratio... 
