[Study of CH4 spectroscopy at low temperature near 1.65 microm]

In the CH4 absorption spectroscopy measurement, especially the measurements at low temperature, the accurate values of the absorption spectral parameters are very important. The absorption spectral parameters are especially important when the authors use parameters to sense and model the atmospheres of the earth and the outer planets. Sometimes the CH4 parameters listed in the HITRAN 2008 database are uncertain to some extent. In order to measure the low temperature absorption spectroscopy of methane, the authors used a cryogenic cell newly developed by ourselves in combination with a distributed feedback (DFB) diode laser as the light source and measured the low stated energy and the rotational angular momentum. And while the authors compared our data with HITRAN 2008, the authors modeled the line intensity changing with the temperature. The authors' measured parameters will be helpful for sensing and modelling the atmospheres of the earth and the outer planets.