1. 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)
Acknowledgements ESA

2. Context
Request by ESA “Define Diagnostic Data Set for upcoming and future delta-validation“
About 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

3. 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.

4. SCIAMACHY Diagnostic Data Set Methodology

5. 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

6. 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

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

8. SCIAMACHY Diagnostic Data Set Results

9. 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

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

11. Ozone column
5096 orbits
ALL orbits

12. Ozone column

13. Limb O3 profile
5096 orbits
ALL orbits

14. Limb O3 profile

15. NO2 column

16. CO column

17. BrO

18. 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 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, …)

19. 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