Development of Shallow-Depth Soil Temperature Estimation Model Based on Thermal Response in Permafrost Area

Abstract

A soil temperature estimation model for increasing depth in a permafrost area in Alaska near the Bering Sea is proposed based on a thermal response concept. Thermal response is a measure of the internal physical heat transfer of soil due to transferred heat into the soil. Soil temperature data at different depths from late spring to the early autumn period at multiple permafrost sites were collected using automatic sensor measurements. From the analysis results, a model was established based on the relationship between the normalized cumulative soil temperatures (CRCST*i,m and CST*ud,m) of two different depths. CST*ud,m is the parameter of the soil temperature measurement at a depth of 5 cm, and CRCST*i,m is the parameter of the soil temperature measured at deeper depths of i cm (i = 10, 15, 20, and 30). Additionally, the fitting parameters of the mathematical models of the CRCST*i,m–CST*ud,m relationship were determined. The measured soil temperature depth profiles at a different site were compared with their predicted soil temperatures using the developed model for the model validation purpose. Consequently, the predicted soil temperatures at different soil depths using the soil temperature measurement of the uppermost depth (5 cm) were in good agreement with the measured results.

Development of a Shallow-Depth Soil Temperature Estimation Model Based on Air Temperatures and Soil Water Contents in a Permafrost Area

“…The altitude is approximately 30 m, and the mean annual temperature and precipitation are −3.1 • C ± 1.4 • C and 258 mm, respectively [39]. The sieve analysis of soil particles conducted by Park et al [21] revealed that the ranges of clay, silt, and sand contents in this area are 6.4%-19.0%, 55.1%-70.0%, and 16.2%-38.5%, respectively, depending upon the sampling depth and location. The test sites were leased from the natives of Council Native Corporation, and there was restriction of moving soils out of the study area.…”

“…In general, soil temperature is predicted during the active soil layer generation period, which is important for capturing sensible and latent heat fluxes (for soil temperatures ≥ 0 • C), the heat energy from the geothermal system, assessing sea ice and permafrost, determining CO 2 and NH 4 emissions patterns, microbial decomposition, and rates of organic matter decomposition, mineralization, and plant growth [20,21]. Several models have been proposed to simulate soil temperatures in various regions and environments [18,[22][23][24].…”

“…In particular, to predict soil temperatures through the correlation of air and soil temperatures by depth, the model proposed by Park et al [21] was modified and employed. The model of Park et al [21] predicts the bottom soil temperature using the topsoil temperature. In particular, to predict soil temperatures through the correlation of air and soil temperatures by depth, the model proposed by Park et al [21] was modified and employed.…”

“…The model of Park et al [21] predicts the bottom soil temperature using the topsoil temperature. In particular, to predict soil temperatures through the correlation of air and soil temperatures by depth, the model proposed by Park et al [21] was modified and employed. The model of Park et al [21] predicts the bottom soil temperature using the topsoil temperature.…”

“…Thermal response was presented using air temperature, for which sufficient measurement data are available. Further improvement to the results of Park et al [21] involved the proposal of a new model for efficiently estimating changes in soil temperatures from the air temperature and soil water content at a depth of 15 cm. The main purpose of this study was to use air temperatures and soil water contents, which are easy to measure, to predict the soil temperature at a shallow depth (15 cm) in an adjacent location.…”