Experimental Evaluation of an Automated Precipitation Sampling Prototype for Isotopic Monitoring in Remote Scenarios.

Abstract

Abstract– Reliable precipitation sampling is essential for stable isotope analysis in hydrology and climate studies, particularly in remote regions where frequent access to monitoring stations is limited. Under such conditions, accumulated sampling over several days is commonly adopted, increasing the risk of cross-contamination and reducing the temporal resolution of isotopic data. This work presents the design and experimental evaluation of an automated precipitation sampling prototype intended to explore the feasibility and limitations of reducing cross-contamination through sequential sample separation. The system integrates commercially available water-level sensors, electromechanical actuators, and a microcontroller-based control architecture, and is evaluated under controlled laboratory conditions. Experimental results show that the conductive water-level sensor provides stable and repeatable measurements once a measurable water level is established, with no significant dependence on water pH or conductivity within the tested range. However, a significant dead volume driven by container geometry and sensor placement introduces systematic detection delays at low flow rates. At the system level, partial automation is achieved, but fully autonomous operation is limited by actuator performance and fixed-threshold control logic. The main contribution of this work lies in the experimental identification of practical limitations and failure modes associated with affordable automated precipitation sampling systems, providing guidance for future designs aimed at improving reliability, autonomy, and suitability for isotopic precipitation monitoring in resource-constrained environments.