Spatial and temporal variability of stratospheric HNO₃ from IASI global measurements

Gaétane Ronsmans (1) , Bavo Langerock (2) , Catherine Wespes (1) , Martine de Mazière (2) , Daniel Hurtmans (1) , Cathy Clerbaux (1, 3) , Pierre-François Coheur (1)

1 Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique
2 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
3 TROPO - LATMOS

Nitric acid (HNO₃) plays a crucial role in the stratospheric ozone cycles but its spatial distribution was until recently only accessible from limb satellite measurements, with medium coverage and sampling. IASI provides since 2007 HNO₃ concentration distributions with unprecedented spatial and temporal sampling, which have not yet been exploited. In this presentation, we will first briefly review the characteristics of the HNO₃ profiles retrieved from IASI and we will show results from a validation exercise, in which the HNO₃ profiles and total columns from IASI are compared with those retrieved from ground-based measurements at several sites. We will then show and discuss the spatial distributions of HNO₃ IASI total and stratospheric columns and assess the seasonal and inter-annual variability of HNO₃ using the 8 years of IASI observations available. Preliminary results from a simple multivariable regression model applied to these time series will be shown to support the analysis and to identify the principal processes driving the variability of stratospheric HNO₃. In this discussion focus will be given onto the polar regions, where the relation of HNO₃ to ozone will be investigated in greater details. With these results, the potential of using IASI for studying stratospheric chemistry will be more generally highlighted.

Domains: Atmospheric and Oceanic Physics [physics.ao-ph]

Gaétane Ronsmans, Bavo Langerock, Catherine Wespes, Martine de Mazière, Daniel Hurtmans, et al.. Spatial and temporal variability of stratospheric HNO₃ from IASI global measurements. 4th IASI International Conference, Apr 2016, Antibes Juan-Les-Pins, France. ⟨insu-01306190⟩