Optimizing implementation strategies for efficient soil water evaporation measurements with multi‐probe heat pulse sensors

Abstract A multi‐probe heat pulse (HP) sensor measures in‐depth variations of water evaporation rates ( E ) in subsurface soil layers. A multi‐probe HP sensor requires an input source of heating power, a high‐frequency data logging system, and computer software for data analysis, which may hinder its adoption for wide use in field applications. This study aims to optimize the measurement configurations via systematic evaluations of vertical probe distributions, heater probe requirements, and thermal property sampling intervals. Field data obtained with an 11‐probe HP sensor revealed that 87% of evaporation occurred within the 0‐ to 23‐mm soil layer during drying cycles, requiring the use of only seven temperature probes and two heater probes (root mean square error < 0.02 mm h −1 vs. full configuration). Thermal property measurement intervals could be extended from 4 to 8 h when timed to capture critical daytime transitions in soil thermal conductivity, maintaining accuracy while reducing the data collection requirement by 38%. Soil thermal gradients accounted for >90% of sensible heat flux values, necessitating ±0.3 mm spacing precision for the uppermost probes. These quantified operational thresholds provide sensor manufacturers and field researchers with evidence‐based design criteria that balance measurement integrity and system efficiency.