1. Rutherford Appleton Laboratory Remote Sensing Group GOME-202-2 slit function analysis PM2 Part 2: Changes – theta_d_0 & SFS shape R. Siddans, B. Latter, B. Kerridge RAL Remote Sensing Group 26 th June 2012 RAL

2. Remote Sensing Group GOME-2 FM202-2: PM2 Slit function analysis Overview of slit-function fitting method New results for FM202-2 (WP2100) - use of new angular parameters from TNO - modification of source line shape to match commissioning measurements Comparisons of results: - FM202-2 to FM202-1 - FM202-2 1mm to FM202-2 0.5mm Error analysis for FM202-2 Discussion re next steps, date of next meeting (FP) AVHRR/GOME-2 co-location, spatial aliasing and geo- referencing (Ruediger Lang) © 2010 RalSpace

3. Remote Sensing Group Measurement setup: 2004: FM202-1 Echelle angles –1.0mm: 73.6-78.376 –0.5mm: 76.0 – 77.188 2012: FM202-2 Echelle angles (same) –1.0mm: 73.6 - 78.376 –0.5mm: 76.0 – 77.284 © 2010 RalSpace

4. Remote Sensing Group SFS predicted wavelengths After PM1, TNO provided updated theta_d_0 & scaling factors (per dataset) Their fitting method meant problems with FPA1 due to low signal (dataset 6 bad) For theta_d_0, FPA3&4 used. For scaling_factor, FPA 2-4 used © 2010 RalSpace v1v2 Dataset 6

5. Remote Sensing Group TNP theta_d_0 & scaling_factor 1 mm measurements theta_d_0 meanscaling factor datasetstart angleend anglestep sizeall FPAFPA1FPA2FPA3FPA4FPA3 &4all FPAsFPA2-4Comments 1-15.2-14.3840.02488.1188.1788.11 88.188.1050.999976460.99997755nice 2-14.384-13.4480.02488.0988.1288.1188.0988.0888.0851.00000851.0000102nice 3-13.424-12.7040.02488.0888.0588.0888.0788.0988.081.0000191.0000207nice 4-12.704-12.0320.02488.1288.1888.1188.1388.1188.120.999940310.9999416nice 5-12.032-11.60.02488.2288.388.22 88.288.210.999706240.99972192 ? Discard extreme angles? 6-16.4-15.4640.02488.1387.8788.15 88.1288.1351.0010830.99985179FPA1 differs very much from the rest here. 7-15.464-15.1280.02488.1288.1788.1488.11 0.999918290.99991769 all 88.0888.188.0988.08 1.00001871.0000203 0.5 mm measurements theta_d_0 meanscaling factor datasetstart angleend anglestep sizeall FPAFPA1FPA2FPA3FPA4FPA3 &4all FPAsFPA2-4Comments 1-14-13.8920.01288.1187.888888.0688.1388.0950.999915440.99991609 2-13.88-13.7120.01288.0488.1288.0788.0388.0288.0251.0000851.0000855 3-13.724-13.5440.01288.188.1688.188.0588.0888.0650.999984330.99998516 4-13.544-13.4360.01287.7487.7687.7387.7187.7487.7251.00080821.0008088very flat curve, hard to find minimum residuals 5-13.436-13.3160.01287.9887.9187.9388.06 1.00000681.0000073 6-13.304-13.1840.01288.0688.188.0988.0188.0488.0251.0000871.0000874Not a nice curve to find minimum for theta_d_0 7-13.184-13.0160.01288.2388.2788.2888.288.2188.2050.999665190.99966569 8-13.016-12.8480.01288.2388.2488.2688.2288.2388.2250.999606120.99960629 9-12.836-12.7160.01288.3588.3888.4988.3188.2988.30.999437710.99943845Hard to fit theta_d_0! Not much difference in residuals all 88.1288.1188.1288.1388.1188.120.999854680.99985521 © 2010 RalSpace Error from FPA1 weak signal

6. Remote Sensing Group 2004 SFS line shape © 2010 RalSpace Modelled Measured(2004) Modelled Measured(2004) 254nm 297nm 300nm 543nm 633nm 1mm slit only

7. Remote Sensing Group 2012 SFS line shape change © 2010 RalSpace Modelled (2004) Measured (2012) 543nm 1mm 633nm 1mm 543nm 1mm 633nm 1mm 633nm 0.5mm 633nm 0.5mm Modelled (2012) Measured (2012) 633nm 1mm 543nm 1mm

8. Remote Sensing Group Laser measurements: Gaussian broadening “The line shape of the SFS lines is influenced by the internal alignment of the stimulus. For the FM2-2 measurements the SFS was taken out of storage and realigned. The alignment was not perfect, resulting in a more Gaussian line shape.” Bad measurment file: –[2010-12-13]_[18_04_34]_FM2_SLITFUN-05EXP-000062-EXP_77.295998.avgfile SFS changes: –Ghosts - Same grating, but didn’t match FM203. Ref. Angle? –From SFS commissioning report, neighbouring peak seems to modify slit peak wavelength as well as shape and wings? © 2010 RalSpace

9. Remote Sensing Group TNO SFS analysis © 2010 RalSpace

10. Remote Sensing Group Change in SFS from diff order © 2010 RalSpace

11. Remote Sensing Group Check ghosts? Values from 2004 © 2010 RalSpace

12. Remote Sensing Group SFS note from MO-TR-TPD-GO-0114 © 2010 RalSpace

13. Remote Sensing Group Example retrieval results

14. Remote Sensing Group © 2010 RalSpace FM202-2 Initial retrievals and test (PM1): FM202_2_0_5 FPA2 (band 2) pix 304-328

15. Remote Sensing Group © 2010 RalSpace FM202-2 Updated parameters (PM2): FM202_2_0_5 FPA2 (band 2) pix 304-328

16. Remote Sensing Group © 2010 RalSpace FM202-2 Updated parameters (PM), Gauss SFS: FM202_2_0_5 FPA2 (band 2) pix 304-328

17. Remote Sensing Group Retrieval as 633nm (laser wls) © 2010 RalSpace