Researchers adjust the optical-path mode.[IMAGE: HEFEI INSTITUTES OF PHYSICAL SCIENCE, CHINESE ACADEMY OF SCIENCES]

A research team led by the Anhui Institute of Optics and Fine Mechanics (AIOFM) of the Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences, together with their collaborators from National Yunlin University of Science and Technology (YunTech), developed an approach to measure atmospheric gas isotopes using off-axis cavity-enhanced absorption spectroscopy (OA-CEAS), a procedure they created.

Combining the wavelength modulation principle with the multi-beam coupling and interference principle, they optimized a small volume long path optical resonator and solved the key problems like temperature and pressure control, spectral line correction and on-line locking frequency.

Up to now, the team has realized the simultaneous, in-situ and on-line monitoring of the key greenhouse gases CO2, CH4 concentrations, and δ12C and δ13C isotopic abundances in the atmosphere. Based on the measured data, the mass conservation equation and Keeling Plot equation have been established enabling study of air pollution source tracing and spatiotemporal distribution characteristics.

Source: Hefei Institutes of Physical Science,

Chinese Academy of Sciences