Comparison of various models of supercooled water loss factor with experimental data at microwaves

An improved formula for the supercooled water loss factor at frequencies 10…180 GHz in the temperature range 0 ... –70 °C is presented. The formula based on the experimental data obtained by the authors on measurements of attenuation in the pore water of silicate materials. The formula contains two terms connected the Debye dependence of the loss factor on frequency and temperature, and non-Debye, determined by the influence of the second critical point of water. Comparison of the proposed formula and the model formulas of other authors is carried out. A significant discrepancy between the calculation results (at several times) of the loss factor at frequencies above 100 GHz and temperatures below –30 °C has been founded. The model based on the measurements provides the most adequate representation of the behavior of the loss factor with an error of ~ 30% in the area of deep supercooling of water and in the upper part of the studied frequency band.