As the infrared thermography has a convenient feature that we can diagnose two-dimensional temperature fields nondestructively and simultaneously at every picture element, it has widely been applied to various engineering applications. Therefore, in this paper, the surface temperature field occurred on Benard-cell convection was visualized and measured by sensing energy emitted from the liquid-gas interface directly as electromagnetic waves using the infrared thermography. The heat transfer phenomena having free surface was also discussed by analyzing the temperature data statistically. Another aim is to confirm the applicability of infrared thermography to quantitative heat transfer measurement on a liquid-gas interface.
