Sensitivity studies for atmospheric carbon dioxide retrieval from atmospheric infrared sounder observations

The atmospheric infrared sounder (AIRS) exhibits great potential for providing atmospheric observation data for long-term regional and global carbon-cycle studies, which are essential for understanding the uncertainty of climate change. The sensitivity of global atmospheric CO₂ retrieval from the AIRS observations by quantifying errors related to CO₂ measurements in the infrared spectrum is investigated. A line-by-line radiative transfer model is used to evaluate the effects of atmospheric temperature profile, water vapor profile, and ozone (O₃) data on the accuracy of CO₂ measurements under five standard atmospheric models. The analytical results indicate that temperature, water vapor, and O₃ are important factors, which have great influences on the sensitivity of atmospheric CO₂ retrieval from the AIRS observations. The water vapor is the most important factor in the tropics, whereas the temperature represents major interference for multitude and subarctic regions. The results imply that precise measurements of temperature, water vapor, and O₃ can improve the quality of atmospheric CO₂data retrieved from the AIRS observations.