High precision detection method of methane in extreme environment based on TDLAS

ABSTRACT The continuous emission of greenhouse gases leads to the sharp rise of environmental temperature. Its content and distribution also affect the atmosphere radiation, climate characteristics, stratosphere troposphere exchange (STE) and circulation in the near-tropopause region. Methane is the second most important greenhouse gas after carbon dioxide, and its concentration has strong gradients near the tropopause. Therefore, the sensitivity, accuracy of methane detection approach in extreme environment have been greatly restricted, and this has become a technical bottleneck for low-temperature and low-pressure gas detection. To address this, a novel 3-dimensional compensation model of temperature and pressure is reported based on the simulation of methane absorption characteristic. Through a detailed investigation, the simulation system and compensation model are evaluated, the detection accuracy is improved by an order of magnitude; the minimum detection limit is ~0.012ppm with integration time is 59s.