Research on trace gas measurement by ICOS with WMS

Integrated cavity output spectroscopy (ICOS) is a very sensitive method of trace gas measurement. It is widely known as its extremely long optical path and characteristics of direct absorption. Wavelength Modulation Spectroscopy (WMS) is another sensitive measurement method that suppresses noise. We combine the ICOS technique and WMS technique to research the trace gas measurement using a narrow band tunable diode laser. By this method we get several absorption peaks of carbon dioxide in atmosphere. To combine ICOS and WMS the sensitivity of trace gas measurement has a significantly increase.