The sensitivities of oxygen dimer (O4) slant column densities (SCDs) were examined by applying temperature-dependent O4cross sections using the radiative transfer model (RTM) calculation with the linearized pseudo-spherical vector discrete ordinate radiative transfer model. For the sensitivity study, we used a newly developed cross section database in place of the database used in the operational algorithm. Newly investigated O4cross section databases for 203 K and 293 K were used for the radiance simulation by interpolating temperature for each atmospheric layer based on the vertical profile of standard atmosphere in the RTM. The effect of the temperature-dependent cross sections was a significant O4SCD increase of 8.3% with dependence on satellite and solar viewing geometries. Furthermore, the O4SCD generally increased by an estimated 3.9% based on the observation geometries of the Ozone Monitoring Instrument. For the long-term comparison, the O4SCD estimated from the temperature-dependent cross sections corrects 20% of the total underestimation of O4SCD between the observation and simulation. Although the surface pressure variation and background aerosol effect also correct the O4SCD discrepancy, the effect of temperature-dependent cross sections was more important than the effects of surface pressure variation and background aerosols. Therefore, temperature dependence of the cross section in the RTM calculation is essential for the accurate simulation of O4SCD.
All Science Journal Classification (ASJC) codes
- Environmental Science(all)
- Atmospheric Science