Solid tide phenomenon of cold water source well temperature and its mechanism: Taking Huangcun well as an example

In this study, we conducted an observation to monitor water temperature solid tide phenomenon of cold water source well in Huangcun, and preliminarily interpreted its formation mechanism. Based on detailed monitoring data of water temperature gradient and the comparison of water temperatures in different depths, we concluded the following conclusions: ① The phase of water temperature solid tide of Huangcun well was opposite to that of water level. ② The water temperature gradient of Huangcun well was of concave-down type. The position that was greatly influenced by influent and effluent water of the aquifer or nearby concaved down the most, and the concave degree getting weaker with the increasing of the distance from the aquifer. ③ There is a rule between data from water temperature sensor and the distance from the observation aquifer: Tidal difference of water temperature became smaller with the increasing of distance until tidal variation faded away. It shows that the water temperature tide phenomenon of the cold-water source well is different from that of hot-water source well. One is endothermic process, and the other is exothermic process, which results in the different characteristics of water thermal dynamics.