1. Radiometric Calibration PROBA-V QWG #2

2. PRESENTATION OUTLINE »Introduction »Stability of PROBA-V »ICP updates since QWG#1 »Outlook »Moon calibration GSICS activities 2

3. Absolute Interband OceansDeserts DC Clouds Temporal RC – IQC: Vicarious Calibration Concept *Sterckx et al. IJRS, 2014; Sterckx et al., TGARS, 2013; Govaerts et al., RSL, 2013 OSCAR* (Optical Sensor Calibration with simulated Radiances) » Relies on combination of various vicarious calibration methods to reduce uncertainty in the calibration results and to verify the different requirements (5 % absolute, 3 % relative) Dark current : oceans during night Equalisation : Antartica (VNIR) Deserts (SWIR) Dark current : oceans during night Equalisation : Antartica (VNIR) Deserts (SWIR)

4. COMPLEXIY OF IN-FLIGHT VICARIOUS CALIBRATION OF PROBA-V 4 Uncertainty in instaneous vicarious calibration results Some methods prone to seasonal dependent biases  Large amount of vicarious calibrations are required to distinguish an instrument related degradation trend from the ‘noise’  Extra complexity due to design of PROBA-V  3 cameras, 9 SWIR strips  Large FOV (prone to BRF uncertainties) TIME REQUIRED

5. COMPLEXITY OF THE IN-FLIGHT CALIBRATION 5 Overlap region

6. PRESENTATION OUTLINE »Introduction »Stability of PROBA-V »VNIR »SWIR »ICP updates since QWG#1 »Outlook »Moon GSICS activities 6

7. INSTRUMENT STABILITY : LEFT CAMERA Results OSCAR Libya-4 (since October 2013) (no A k updates considered) 7

8. INSTRUMENT STABILITY : CENTER CAMERA Results OSCAR Libya-4 (since October 2013) (no A k updates considered) 8

9. INSTRUMENT STABILITY : RIGHT CAMERA Results OSCAR Libya-4 (since October 2013) (no A k updates considered) 9

10. INSTRUMENT STABILITY : SUMMARY VNIR 10

11. INSTRUMENT STABILITY : CENTER CAMERA Results Moon Calibration (since October 2013) (no A k updates considered) 11

12. INSTRUMENT STABILITY : SUMMARY VNIR Libya4 12 Moon

13. INSTRUMENT STABILITY : LEFT CAMERA Results OSCAR Libya-4 (since October 2013) (A k updates considered) 13

14. INSTRUMENT STABILITY : CENTER CAMERA Results OSCAR Libya-4 (since October 2013) (A k updates considered) 14

15. INSTRUMENT STABILITY : RIGHT CAMERA Results OSCAR Libya-4 (since October 2013) (A k updates considered) 15

16. VERIFICATION OF ABSOLUTE RADIOMETRIC REQ. (5 %) OVER RAYLEIGH LEFT camera (BLUE, RED) 16 NIR band = ref

17. VERIFICATION OF ABSOLUTE RADIOMETRIC REQ. (5 %) OVER RAYLEIGH CENTER camera (BLUE, RED) 17 NIR band = ref

18. VERIFICATION OF ABSOLUTE RADIOMETRIC REQ. (5 %) OVER RAYLEIGH RIGHT camera (BLUE, RED) 18 NIR band = ref

19. VERIFICATION OF INTER-BAND CALIBRATION ACCURACY OVER DCC 19

20. PRESENTATION OUTLINE »Introduction »Stability of PROBA-V »VNIR »SWIR »ICP updates since QWG#1 »Outlook »Moon GSICS activities 20

21. INSTRUMENT STABILITY : LEFT CAMERA -SWIR Results OSCAR Libya-4 (since October 2013) (no A k updates considered) 21

22. INSTRUMENT STABILITY : RIGHT CAMERA -SWIR Results OSCAR Libya-4 (since October 2013) (no A updates considered) 22

23. INSTRUMENT STABILITY : CENTER CAMERA Results OSCAR Libya-4 (since October 2013) (no A updates considered) 23

24. INSTRUMENT STABILITY : SUMMARY SWIR Libya4 (status 15/10/2015) 24 Moon

25. PRESENTATION OUTLINE »Introduction »Stability of PROBA-V »ICP updates since QWG#1 »Outlook »Moon GSICS activities 25

26. INSTRUMENT STABILITY : SUMMARY SWIR Libya4 (status 15/10/2015) 26 2.8 % update feb 2015

27. INSTRUMENT STABILITY : SUMMARY SWIR Libya4 (status 15/10/2015) 27 ICP file update of 2.8 % in feb 2015 ICP update Aug/Sept 2015

28. INSTRUMENT STABILITY : SWIR ICP FILE UPDATE 28 % decrease since October 2013: status August 2015 ** Desert BRF RPV parameters MISR/MODIS (Govaerts Y., Sterckx, S., Adriaensen, S, 2013) * Desert BRF RPV parameters POLDER/ATSR2 (Govaerts and Clerici, 2004) 013

29. COMPLEXITY ICP UPDATE : AN EXAMPLE 29

30. COMPLEXITY ICP UPDATE : AN EXAMPLE 30

31. CALIBRATION: UPDATES- TRACEABILITY USER 31

32. RADIOMETRIC CALIBRATION:OUTLOOK 32 »1st Reprocessing of PROBA-V archive (scheduled for first semester 2016) »Bias (inter-camera/inter-band) adjustments to be implemented from start of operations »Degradation : smoothly changing absolute calibration parameters (  now: step-wise adjustment) »Fitting of trending model »ICP files Real-time processing : ideally function could be used then operationally to predict the absolute calibration parameter valid for the next month based on all previously acquired data, without risk of unwanted fluctuations in the updates

33. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL 33 »Global Space-Based Intercalibration System : initiative of the weather satellite organisations in 2005 (WMO and CGMS) »Try to establish means and methods to compare the performance of different operational satellites »Write ATBDS and even implement prototypes to be used by members/community. »Lunar Calibration subgroup : founded at GSICS annual meeting March 2014 »EUMETSAT : Collaboration with USGS –> GSICS reference implementation of USGS ROLO » Lunar Calibration workshop in Darmstadt

34. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL 34 »Goal of GSICS working group »apply to all participating sensors : stability trending »Adapt current ROLO model to be able to perform absolute calibration »Perform intercomparisons between sensors »First step : inter-compare VITO results with GSICS results »Provide recorded center of moon time and spacecraft position to the model »Compare Observed with GSICS simulated Total Irradiance

35. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL Result : BLUE 35 TREND (10/2013)GSICSVITO year-0.30%-0.11% total-0.73%-0.22%

36. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL Result : RED 36 TREND (10/2013)GSICSVITO year 0.30% 0.52% total 0.73% 1.02%

37. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL Result : NIR 37 TREND (10/2013)GSICSVITO year-0.294%-0.23% total-0.725%-0.44%

38. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL Result : SWIR 38 TREND (10/2013)GSICSVITO year-0.06%-0.09% total-0.16%-0.17% 3% 2%

39. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL Result : GEOMETRY 39

40. LUNAR CALIBRATION : COMPARISON WITH GSICS MODEL Result : Conclusions 40 »GSICS model is applied to the PROBA-V moon data »PROBA-V stable trending results are confirmed by the GSICS model »VITO implementation has larger variation over time : to be investigated