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NOAA-18 SBUV/2 OV AE RESULTS L. Flynn
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NOAA-18 SBUV/2 OV and AE

• 15 OV SBUV/2 tests completed
• Some additional tests performed for AE
• Instrument characterization and calibration
  provided to operations by SSAI (GSFC Code 613)
• Earliest ACF data delivery yet
• Earth view data taken almost from the start is
  available for reprocessing

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NOAA-18 SBUV/2 OV and AE

• Additional tests were not included in formal OV
• Five tests were in OV for NOAA-17 SBUV/2
• Additional tests to characterize stray light
• Specification for stray light is inadequate
• Position mode and day-time diffuser deployment
• Not all tests performed (not considered OV)
• TOARs closed/inactive before launch (CDR)
• No need seen to add OV tests in these areas
• SBUV/2 did not take advantage of AMSU off/on
• Regular solar measurements not started earlier
• Regular operational schedule implementation
  delayed

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Additional Tests Recommended

• Test_SBUVA01 Range 3 Cathode
• Test_SBUVA02 SO2 (Discontinue)
• Test_SBUVA03 EP/TOMS Measurements (For NASA)
• Test_SBUVA04 CCR/Monochromator
• Test_SBUVA05 OOBR (Analysis of Earth position
  mode)
• Test_SBUVA06 Backup Grating Encoder Baseline
• Test_SBUVA07 Backup Diffuser Position Baseline
  
• Test_SBUVA08 8-second Range 3 noise (from
  SBUVA01)
• Test_SBUVA09 Noisy Range 1 (Analysis)
• Test_SBUVA10 OOBR (Earth view Mg II and other
  features)
• Test_SBUVA11 Compare to NOAA-16 SBUV/2
  (Analysis)
• Test_SBUVA12 Compare to EOS Aura OMI
  (Analysis)
• Test_SBUVA13 Deploy solar diffuser on day side
  (earth-shine)
• TRENDING
• Throughput/Solar for evidence of dichroic
  outgassing as seen with
• NOAA-17 SBUV/2. Start weekly solar
  measurements sooner.
• Range 3 Anode/Cathode. Repeat SBUVA01.
• Mg II Index. Start sooner, take in Earth view
• Photometer/Monochromator performance. Repeat
  SBUVA04 over

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Parameters Tables from NOAA-17 AE Report

• TABLE 15.1 Ozone Processing Calibration Data for
  NOAA-17 SBUV/2
• Quantity Location
• Wavelength Calibration Ebert Coefficients Table
  6.1 p. 29
• Standard Ozone Wavelengths Table
  6.8 p. 32
• Radiance Calibration Constants Table
  12.3 p. 86
• Irradiance Calibration Constants Table
  12.2 p. 86
• Electronic Offsets Table
  5.1 p. 17
• Non-linearity Corrections Table
  10.1 p. 62
• PMT Temperature Correction Table
  8.1 p. 47
• Inter-range Ratio IRR12
  p. 53
• Inter-range Ratio IRR23A (anode mode)
  p. 53
• Inter-range Ratio IRR23C (cathode mode) Table
  9.1 p. 53
• Table
  9.2 p. 54
• Goniometric Correction Table
  7.1 p. 40
  
  
• Table
  7.2 p. 40
• Table
  7.3 p. 41
• Day-1 Solar Irradiances Table
  13.1 p. 91
• Total Ozone Pair Adjustment Factors Table
  14.1 p. 94

Stray light characterization was delivered later,
separately.
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NOAA-18 Day-1 Solar Irradiance

• Channel Wavelength Irrad_new Diff
• 1 251.97 39.03 -9.4
• 2 273.64 169.15 -12.7
• 3 283.10 307.87 -7.1
• 4 287.67 316.23 -7.1
• 5 292.30 516.84 -5.9
• 6 297.58 506.99 -5.1
• 7 301.97 428.52 -5.6
• 8 305.84 553.92 -6.6
• 9 312.61 659.57 -4.4
• 10 317.54 764.59 -4.5
• 11 331.25 977.00 -1.6
• 12 339.86 1019.89 -2.3
• CCR 378.62 1204.65 -7.6

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NOAA-18 Initial Parameters Adjustments

• 1. Day -1 Irradiance adjustments are on the
  preceding slide..
• 2. Anode IRR23. On-orbit inter-range ratio for
  Range 3 anode data (IRR23A) is significantly
  lower than the pre-launch value. The value
  derived from on-orbit data is IRR23A 92.459 a
  change of -7.5 from the pre-launch value.
• 3. Range 2 Non-Linearity. There was an error in
  the pre-launch non-linearity correction for high
  Range 2 signals (gt45,000 counts). A simple
  additional linear correction is given by
• CF CI/(1.0(6.46933e-07(CI-45000
  ))) for CI gt 45000
• 4. Ozone tables and wavelengths. The pre-launch
  wavelength calibration needs to be adjusted by
  approximately 0.9 grating positions. This
  requires revision of the total ozone tables and
  wavelength scale values.
• 5. Time-Dependent ACF. Range 3 cathode
  measurements in early June and early July
  indicate a PMT sensitivity change of
  approximately -1 during that time. Since
  regular solar measurements are not yet available,
  a linear extrapolation of these measurements was
  used to produce a time-dependent ACF with
  identical values at all wavelengths for SSAI
  ozone processing. This is important for profile
  ozone. Note that the rate of PMT change derived
  from IRR23C data typically slows after the first
  few months of operation.

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Comparison of equatorial zonal mean Ozone
profiles for SBUV/2 instruments
NOAA-18 Blue NOAA-17 Green NOAA-16 Red
18-17 Blue 18-16 Green 17-16 Red
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NOAA-18 SBUV/2 Monitoring
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Backup

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• 1. Day -1 Irradiance. The initial NOAA-18 solar
  irradiance measurements are low relative to
  reference data, with differences ranging from
  2-4 at long wavelengths to 8-10 at short
  wavelengths. Diffuser reflectivity tests show no
  significant change from pre-launch values, so we
  believe that the radiometric calibration has
  changed. The simplest correction for ozone
  processing at this time is to provide new "Day 1"
  irradiance values processed with the pre-launch
  calibration constants, so that observed albedo
  values are consistent with the albedo
  calibration. At a later date, SSAI will supply
  revised calibration constants for both radiance
  and irradiance data as a long-term solution.
  This is the procedure that was used for NOAA-17
  SBUV/2, and will yield the same albedo
  calibration for NOAA-18 as our initial fix. The
  revised "Day 1" irradiance values and the
  difference from current data are listed below.
• 2. Anode IRR23. The on-orbit inter-range ratio
  for Range 3 anode data (IRR23A) is significantly
  lower than the pre-launch value supplied by SSAI.
  Our recommended value derived from on-orbit data
  is
• IRR23A 92.459 a change of -7.5 from the
  pre-launch value.
• 3. Range 2 Non-Linearity. SSAI identified an
  error in the pre-launch non-linearity correction
  for high Range 2 signals (45,000 counts), and
  derived a linear adjustment. The maximum albedo
  correction for ozone processing is approximately
  -0.9 at 55,000 counts Range 2 (higher signals
  are processed in Range 3). The corresponding
  impact on profile ozone could be up to 1.0-1.5,
  depending on wavelength. A simple statement to
  apply this correction is
• C_true C_NL2/(1.0(6.46933e-07(C_NL2-45,0
  00)))
• where
• C_NL2 Range 2 counts after using pre-launch
  non-linearity correction
• C_NL2 45,000 counts
• C_true Corrected Range 2 counts
• 4. Ozone Tables. On-orbit measurements suggest
  that the pre-launch wavelength calibration
  supplied by SSAI needs to be adjusted by
  approximately 0.9 grating positions. We have
  generated revised tables for the SSAI ozone
  processing code in order to have a more accurate
  Ring effect correction. This adjustment changes
  total ozone values by a few DU to as much as 4-5
  DU in some cases. Huang can provide you with
  these tables. Please note that we have not
  updated wavelength scale values at this time,
  only the tables.
• 5. Time-Dependent ACF. Range 3 cathode
  measurements in early June and early July
  indicate a PMT sensitivity change of
  approximately -1 during that time. Since
  regular solar measurements are not yet available,
  a linear extrapolation of these measurements was
  used to produce a time-dependent ACF with
  identical values at all wavelengths for SSAI
  ozone processing. The corresponding data set can
  be supplied by Huang. This term has only a small
  effect on total ozone through the calculated
  reflectivity, and is more important for profile
  ozone. Note that the rate of PMT change derived
  from IRR23C data typically slows after the first
  few months of operation.

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NOAA-17 Report on Additional OV and AE

• Out-of-band response
• Ball measurements
• Ozone impact
• Correction
• Special measurements
• SO2
• EPTOMS
• Photometer
• OMPS Mapper (TBD)
• Operational schedule
• Sweep mode 1/day per week (1/6 coverage)
• Solar diffuser in conjunction with NOAA-16 SBUV/2
• Mg II Index 2/day
• Range 3

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