iFlow: a new graphical user interface to quantify thermal properties and advection from temperature time-series analysis

The last years have seen an increase interest in quantifying hyporheic and water exchange between stream and aquifer due to the need for better water resource management. Pursuant in this effort, several approaches have been developed based on using groundwater temperature as a passive tracer. These approaches may differ in time signal analysis, solutions for the heat transport equation under different boundary conditions or solving the heat transport equation numerically to extract the advective flux. Few of these approaches have been coded in available software. However, available codes do not separate the processes of problem conceptualization and signal analysis. Many approaches only analyze a single frequency or extract only a singular information, (e.g., phase or amplitude), and rarely quantify uncertainty. However valuable information can be extracted by frequencies other than the daily frequency. Here, we provide a novel graphical user interface, GUI, that incorporates a streamlined data analysis procedure. It guides the user through data visualization and selection of signal analysis. The software allows both single- and multi-frequencies approaches, and different reconstruction techniques of the fluxes and system thermal properties based on different boundary conditions. The GUI is developed in the multi-platform Python language and with modular structure, which allows integration and additions of new signal processing approaches and solutions to partial differential equation and boundary conditions that better describe the process.