SAGE III/ISS ozone and NO<sub>2</sub> validation using diurnal scaling factors
oleh: S. A. Strode, S. A. Strode, G. Taha, G. Taha, L. D. Oman, R. Damadeo, D. Flittner, M. Schoeberl, C. E. Sioris, R. Stauffer
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2022-10-01 |
Deskripsi
<p>We developed a set of solar zenith angle, latitude- and altitude-dependent scaling factors to account for the diurnal variability in ozone (O<span class="inline-formula"><sub>3</sub>)</span> and nitrogen dioxide (NO<span class="inline-formula"><sub>2</sub>)</span> when comparing Stratospheric Aerosol and Gas Experiment (SAGE) III/ISS observations to observations from other times of day. The scaling factors are calculated as a function of solar zenith angle from the four-dimensional output of a global atmospheric chemistry model simulation of 2017–2020 that shows good agreement with observed vertical profiles. Using a global atmospheric chemistry model allows us to account for both chemically and dynamically driven variability. Both year-specific scale factors and a multi-year monthly climatology are available to decrease the uncertainty in inter-instrument comparisons and allow consistent comparisons between observations from different times of day. We describe the variability in the diurnal scale factors as a function of space and time. The quasi-biennial oscillation (QBO) appears to be a contributing factor to interannual variability in the <span class="inline-formula">NO<sub>2</sub></span> scaling factors, leading to differences between years that switch sign with altitude. We show that application of these scaling factors improves the comparison between SAGE III/ISS and OSIRIS NO<span class="inline-formula"><sub>2</sub></span> and between SAGE III/ISS and OMPS LP, OSIRIS, and ACE-FTS <span class="inline-formula">O<sub>3</sub></span> observations. The comparisons between SAGE III/ISS <span class="inline-formula">O<sub>3</sub></span> for sunrise or sunset vs. Microwave Limb Sounder (MLS) daytime or nighttime observations are also more consistent when we apply the diurnal scaling factors. There is good agreement between SAGE III/ISS V5.2 ozone and correlative measurements, with differences within 5 % between 20 and 50 km when corrected for diurnal variability. Similarly, the SAGE III/ISS V5.2 <span class="inline-formula">NO<sub>2</sub></span> agreement with correlative measurement is mostly within 10 %. While the scale factors were designed for use with SAGE III/ISS observations, they can easily be applied to other observation intercomparisons as well.</p>