Definition of SCIAMACHY Diagnostic Data Set SQWG-3, PM1, IUP Bremen, 20 Oct 2014 Definition of SCIAMACHY Diagnostic Data Set D. Hubert, J. Granville, A. Keppens, F. Hendrick and J.-C. Lambert Space Aeronomy Institute of Belgium (BIRA-IASB) daan.hubert@aeronomie.be Acknowledgements ESA

Context Request by ESA “Define Diagnostic Data Set for upcoming and future delta-validation“ About 10000 orbits with reliable SCIAMACHY data With optimal coverage of co-locations between SCIAMACHY and correlative observations representative in time and latitude for different products (O3, NO2, BrO, CO) for different ground-based instruments (Dobson, Brewer, UV-vis, O3 sonde, O3 lidar, FTIR) Consideration by DLR Preferably 5000 orbits, so repeat cycles remain short More orbits can be added when (really) needed

SCIAMACHY Diagnostic Data Set Objective Find a list of about 5000 orbits, optimized for ground-based delta-validation studies of nadir and limb L2 products.

SCIAMACHY Diagnostic Data Set Methodology

Preparation : data selection 1. Discard 2223 orbits with unreliable SCIAMACHY data during & after decontamination during instrument/platform anomalies after Envisat orbit lowering 2. Discard screened SCIAMACHY and correlative data 3. Co-location criteria Product Instrument Space Time O3 column Brewer 150km same day Dobson O3 / NO2 column DOAS SAOZ twilight zone same sunrise/set BrO column/profile 300km CO column FTIR 3h O3 profile O3 sonde 500km 12h O3 lidar

Use a two step procedure Step 1 Continuous sampling of time series at 1 key station per latitude band for each correlative analysis O3 column : Dobson, Brewer, UV-vis O3 profile : O3 sonde and O3 lidar BrO column & profile : UV-vis NO2 column : UV-vis CO column : FTIR Purpose Maximal sampling at a selection of key stations In-depth studies of temporal structure

Use a two step procedure Step 2 Continuous sampling of time series per latitude band Purpose Representative (lat,time) sample (Pseudo)-global studies

SCIAMACHY Diagnostic Data Set Results

Statistics Number of SCIAMACHY-GND pairs for two different orbit selections Product Instrument 5096 orbits 7096 orbits O3 column Brewer 14995 19188 Dobson 12582 16486 UV-vis 12573 16904 NO2 column 11560 15254 BrO column/profile 1386 1643 CO column FTIR 5656 6054 O3 profile O3 sonde 6826 8202 O3 lidar 1832 2054 All 67410 85785

Focus on 5000 orbit selection Fraction of total possible co-locations Size of diagnostic orbit list

Ozone column 5096 orbits ALL orbits

Ozone column

Limb O3 profile 5096 orbits ALL orbits

Limb O3 profile

NO2 column

CO column

BrO

SCIAMACHY Diagnostic Data Set Summary Final selection ready by mid next week need to double-check O3 & NO2 column data The current 5096 selected orbits provide 67410 SCIA-GND pairs 28% of total SCIA-GND co-location data set with 10% of SCIA orbits excellent sampling at a few key stations representative global coverage over the entire mission optimal balance between SCIAMACHY products (O3, NO2, CO, BrO) The selection is NOT optimized for other products satellite inter-comparison studies unreliable SCIAMACHY data (decontamination, …) solar occultation data sequential orbits (e.g. 1 day per month, …)

SCIAMACHY Diagnostic Data Set Request The validation teams need to be informed about what changes are expected targeted studies are possible if we know where & when to look for which product