Flux sensors are specialized instruments designed to measure the transfer of gases, heat, or water vapor between the Earth’s surface and the atmosphere. They are commonly used in meteorology, climatology, and environmental research to study processes such as carbon dioxide exchange, evapotranspiration, and energy fluxes.

Modern flux sensors often integrate gas analyzers with sonic anemometers, allowing simultaneous measurement of gas concentrations and three-dimensional wind components. This integration enables accurate calculation of fluxes using the eddy-covariance technique.