1. OZONE PRODUCTS S5P Verification Workshop 20/05/2015 MPIC, Mainz

2. Verification: work completed Total Ozone – Simulated retrieval comparsions completed (RSS/polarisation/viewing geometry/albedo) – Offline Prototype algorithm speed increased using LUT – Offline algorithm extensively compared to other products Tropical Tropospheric Ozone – CCD prototype and verification algorithms products compared to other data products – Cloud slicing prototype compared to sondes Ozone Profile – Linear (error mapping) and non-linear (iterative) retrieval simulations nearly completed

3. Improved Performance of Offline Total Ozone Algorithm Look-up table version of GODFIT No systematic dependence introduced by the method. The full reprocessing has been achieved within 3 weeks (the processing is more than 10 times faster compared to the online algorithm). No Soft calibration applied for OMI!! Motivation: Full reprocessing of the OMI L1 data set at the end of year 1. Concept: All online RT calculations are replaced by interpolation through pre- calculated tables of radiances. Specs: o 9 dimensions: 3 angles, T°, Scene altitude and albedo, month, latitude, total O 3 o Jacobians computed from the radiance LUT itself. o Final size: ~370 Gbytes. o Has been generated in 20 days using 32 cores (2.66GHz) LUT – online difference (%)

4. Offline Total Ozone Comparisons to other reference total ozone products OMI_GODFIT - OMI_TOMS OMI_GODFIT - OMI_DOAS OMI-GODFIT - SBUV

5. 5 Tropospheric ozone CCD comparisons WFDOAS Prototype Verification Mean diff= -2.4 DU STDEV=0.8 DU Difference

6. Ozone Profiles Linear simulations (error mapping)Non-linear iterative simulations

7. Verification: outstanding tasks Total Ozone – Comparison of NRT(DOAS) and offline (direct fit) using real data (GOME-2/OMI) – Look at consistency between total column and integrated total ozone from profile – Some differences remain in modelling of Raman scattering between LIDORT and DISAMAR Tropical Tropospheric Ozone – Make comparisons with ozone profiles (Bremen) up to 14km (CCD) – Comparisons using 1 month of TCO3 from real data processed by S5P total column algorithms (CCD/Cloud Slicing) – Use of operational total ozone for Cloud Slicing Ozone Profile – Comparisons of retrievals using real data and identification of metrics for comparison. Considering using a model for cross-comparison. – Close off linear and non-linear simulation retrieval work by direct comparison to prototype

8. Comparisons of retrievals with real data GOME 2 data will be used for comparison of products based on real measurements – GOME-2 MetOp-B (minimal degradation, full spectral coverage) – Action on all groups to identify what would be good day(s)/cases to process – ~1 day per season (inc. ozone hole case) Consider use of a model (MACC) for select days for cross- comparison, particularly for ozone profiles 1 month of total column product based on real measurements will be provided to the tropical tropospheric groups

9. Summary points for feeding back to WG 1.It would be very useful to have the S5P NPP cloud product for Band 3, in addition to that for NIR/SWIR bands. Cloud fraction/mask algorithm can do this but might be dependent on processing resources (and storage). 2.AMT paper possibilities being considered by each product/group. Some limitations as much has been published already for some algorithms. Opportunity for including verification results in prototype algorithm papers. 3.Individual slides for ATMOS conference to be provided by each product/group.