On the added value of chemical reanalyses in the middle atmosphere: lessons learned from the BASCOE Reanalysis of Aura MLS.
Abstract
With the advent of spaceborne observation of the earth atmospheric composition since 2000, several research and meteorological centres have developed or extended their data assimilation system to analyse these new types of observations. More recently, chemical reanalyses have been produced, including the BASCOE (Belgian Assimilation System for Chemical ObsErvations) Reanalysis of Aura MLS version 2 (BRAM2, Errera et al., ACPD, 2019). BASCOE is based on a Chemistry Transport Model (CTM) accounting for the advection, the chemistry and the microphysics of the Polar Stratospheric Clouds (PSC), and is driven by the ERA-Interim dynamical fields. The period of the reanalysis is between August 2004 and August 2019. Eight MLS species have been assimilated: O3, CO, H2O, N2O, HNO3, HCl, ClO and CH3Cl. BRAM2 6-hourly gridded outputs are available after registration at the following link http://strato.aeronomie.be > Datasets > BRAM2.
In this presentation, we will discuss the value that BRAM2 can add to the model and/or the observations, in particular (1) in the middle stratosphere to analyse drifts between instruments (e.g. between MLS and the Atmospheric Chemistry Experiment Fast Fourier Transform), (2) in the tropical tropopause layer to diagnose the vertically oscillating biases in MLS ozone observations, and (3) in the polar vortex to deliver a complete picture of the evolution of the stratospheric composition when affected by PSC microphysics or by descent of mesospheric air.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A44F..07E
- Keywords:
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- 0340 Middle atmosphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0341 Middle atmosphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0342 Middle atmosphere: energy deposition;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0394 Instruments and techniques;
- ATMOSPHERIC COMPOSITION AND STRUCTURE