Comparison of soil frost and thaw depths measured using frost tubes and other methods

摘要: Abstract Frost tubes filled with methylene blue solution are commonly used tools for measuring soil frost and thaw depths in the field. To quantify accuracy of this method, were measured agricultural fields Tokachi district northernmost Japan's main islands. The using coincided those determined from direct observations profile. root mean square error (RMSE) between these two methods (i.e. observations) was ± 0.035 m, which is expected region. temperature profile characterized over four winters thermocouples to estimate an experimental field central Tokachi. also during period. A scatter diagram obtained showed a concentration points along 1:1 line. RMSE ± 0.028 m, suggesting that depth can be accurately estimated Unlike depth, consistently deeper than through observation hardness. This might true because frozen around tube thawed earlier greater insolation heat conduction atmosphere resulting decrease snow cover as result snowmelt tube. However, approximately linear relation, calibrated relation.