1. NATIONAL POLAR-ORBITING PARTNERSHIP VERIFICATION AND EARLY OPERATIONS FOR THE OZONE MAPPING AND PROFILE SUITE OMPS IGARSS, Munich DR Lawrence Flynn, Didier Rault, Glen Jaross, Irina Petropablovskikh, Craig Long, Colin Seftor, Eric Beach, Wei Yu, Jianguo Niu, Dustin Swales, Chunhui Pan, Xiangqian Wu, Zhihua Zhang, Yan Hao Session: MO4.13: Suomi National Polar-orbiting Partnership (NPP) Monday, July 23, 15:40 - 17:20 Paper Code: MO4.13.1, Paper Number: 1746 See posters in the next session: MOP.P.6 and MOP.P.7

2. Short Abstract NOAA, through the Joint Polar Satellite System (JPSS) program, in partnership with National Aeronautical Space Administration (NASA), launched the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite on October 28, 2011. The JPSS program is executing the NPP Calibration and Validation (Cal/Val) program to ensure the data products comply with the requirements of the sponsoring agencies. The Ozone Mapping and Profiler Suite (OMPS) consists of two telescopes feeding three detectors measuring solar radiance scattered by the Earth's atmosphere and surface, and solar irradiance by using diffusers [1]. The measurements are used to generate estimates of total column ozone and vertical ozone profiles. The validation efforts make use of external resources, in the form of ground-based and satellite- based measurements for comparisons, and apply internal consistency methods developed over the last thirty years. This paper provides information on the state of the execution of the OMPS Cal/Val Plan with emphasis on the measures of the instrument performance from internal consistency analysis techniques and comparisons to other satellite instrument products for the validation of the NPP OMPS environmental data products. [1] Juan V. Rodriguez, et al., “An overview of the nadir sensor and algorithms for the NPOESS ozone mapping and profiler suite (OMPS),” Proc. SPIE, 4891, April 2003, DOI: 10.1117/12.467525.

3. OMPS Fundamentals NOAA, through the Joint Polar Satellite System (JPSS) program, in partnership with National Aeronautical Space Administration (NASA), launched the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite on October 28, 2011. The Ozone Mapping and Profiler Suite (OMPS) consists of two telescopes feeding three detectors measuring solar radiance scattered by the Earth's atmosphere and solar irradiance by using diffusers. The measurements are used to generate estimates of total column ozone and vertical ozone profiles. The nadir mapper (total column) sensor uses a single grating monochromator and a CCD array detector to make measurements every 0.42 nm from 300 nm to 380 nm with 1.0-nm resolution. It has a 110° cross-track FOV and 0.27° along-track slit width FOV. The measurements are currently combined into 35 cross-track bins: 3.35° (50 km) at nadir, and 2.84° at ±55°. The resolution is 50 km along-track at nadir, with a 7.6-second reporting period. The instrument is capable of making measurements with much better horizontal resolution. The nadir profiler sensor uses a double monochromator and a CCD array detector to make measurements every 0.42 nm from 250 nm to 310 nm with 1.0-nm resolution. It has a 16.6° cross-track FOV, 0.26° along-track slit width. The current reporting period is 38 seconds giving it a 250 km x 250 km cell size collocated with the five central total column cells. The limb profiler sensor is a prism spectrometer with spectral coverage from 290 nm to 1000 nm. It has three slits separated by 4.25° with a 19-second reporting period that equates to 125 km along-track motion. The slits have 112 km (1.95°) vertical FOVs equating to 0 to 60 km coverage at the limb, plus offsets for pointing uncertainty, orbital variation, and Earth oblateness. The CCD array detector provides measurements every 1.1 km with 2.1-km vertical resolution. The products for the Limb Profiler are not discussed here.

4. Outline Brief instrument / product overview Cal/Val Team and Others Examples of OMPS Performance –Solar irradiance measurements –Radiance measurements Signal to Noise Geolocation / Reflectivity South Atlantic Anomaly Wavelength Scale and Ring Effect Initial residuals for the Nadir Profiler –Products Limb Ozone Profile Retrievals Total Column Ozone Maps Cross-track Bias in Total Ozone Aerosol Index

5. OMPS Instrument Design Nadir Mapper UV Backscatter, grating spectrometer, 2-D CCD TOMS, SBUV(/2), GOME(-2), OMI 110 deg. cross track, 300 to 380 nm spectral, 1.1nm FWHM bandpass Total Column Ozone, UV Effective Reflectivity, and Aerosol Index Daily Maps Nadir Profiler UV Backscatter, grating spectrometer, 2-D CCD SBUV(/2), GOME(-2), OMI Nadir view, 250 km cross track, 270 to 310 nm spectral, 1.1 nm FWHM bandpass Ozone Vertical Profile, 7 to 10 KM resolution Limb Profiler UV/Visible Limb Scatter, prism, 2-D CCD array SOLSE/LORE, OSIRIS, SAGE III, SCIAMACHY Three 100-KM vertical slits, 290 to 1000 nm spectral Ozone Vertical Profile, 3 KM vertical resolution The calibration concepts use working and reference solar diffusers. Instrument and FOV Graphics from BATC

6. Ozone Calibration and Validation Team Members’ Roles & Responsibilities 6 AreaNameOrganizationFunding Agency Task Validation and Comparisons L. FlynnNOAA/NESDISJPSSInternal and Satellites Ground-based Data I. Petropav- lovskikh NOAA/ESRLJPSSDobson and Umkehr ApplicationsC. LongNOAA/NCEPJPSS/JCSDAAssimilation LimbP.K.. BhartiaNASA GSFCNASA NPPR&D ClimateR. McPeters L. Flynn NASA GSFC NOAA/NESDIS NASA NOAA/NCDC CDR & Reprocessing InstrumentS. Janz B. Sen G. Jaross X. Wu NASA GSFC NGAS NASA (SSAI) NOAA/NESDIS NASA/JPSS JPSS NASA/JPSS JPSS RDR and SDR

7. OMPS Nadir Mapper Spectra The plot at the top of the following slide shows a sample OMPS Nadir Mapper solar spectrum measured in January. The initial calibration, goniometry and wavelengths scales have been applied. Notice the Fraunhofer lines, e.g., a deep one near 360 nm. The plot in the middle shows a sample spectrum for the Earth View data for the nadir field-of view. The plot on the bottom shows the ratio of the first two spectra. Notice that much of the structure in the solar spectrum cancels out in the ration. Also notice the variations between 320 and 330 nm produced by differential ozone absorption with wavelength. After further analysis, the wavelength scales have been revised with shifts on the order of 1Å.

8. Solar Irradiance Earth Radiance Radiance/Irradiance Ratio Ozone Absorption Features Fraunhoferlinien Typical spectra from 310 to 380 nm for OMPS Nadir Mapper Wavelength, nm 310380

9. Nadir Mapper Earth Radiance Signal to Noise Ratio Estimates Empirical Orthogonal Function (EOF) decomposition analysis was used to investigate the measurement noise. The covariance matrices were constructed for each of the 35 cross-track positions for three separate wavelength intervals ([305,325], [320,345], and [340,380] nm) for six orbits of earth view radiances. The radiances for each of the 3X35X1800 spectral intervals were normalized by using the overall average spectrum for that cross track position and interval, and a fit with a third degree polynomial in wavelength before computation of the 105 covariance matrices. For each matrix, the six largest patterns were considered to be signals and the remaining variations were regarded as noise. The figure on the next slide shows RMSR values that equate to Signal-to-Noise Ratios (SNR) better than 2000:1 at most wavelengths for most cross-track positions with the SNR dropping to 1000:0 at the shorter wavelengths. No screening of obvious outliers was performed on the radiances, and this is apparent in the scatter of results at 320 nm.

10. EOF/SNR analysis for six orbits (~1800 scans) OMPS NM on 1/28/2012 using three wavelength ranges (305-325, 320-345, 340-380) for 35 CT 0.1 is equivalent to an average SNR of 1000:1.

11. OMPS Geolocation This image shows the effective reflectivity (0% to 30% for the 380-nm Channel for part of an orbit of small Field-of-View (5 KM X 10 KM at Nadir) measurements made by the OMPS Nadir Mapper in a special diagnostic mode on January 26, 2012. The Qatar peninsula sticking into the Persian Gulf in the middle of the picture lies along the nadir view of the orbital track and gives a preliminary assurance of the geolocation at better the 5 KM.

12. Examination of South Atlantic Anomaly (SAA) effects and product flagging. The noise/spikes below show the expected increases when an orbital path falls with within the SAA but return to normal levels after passing through it. The OMPS was designed to use the OMPS Limb Profiler retrievals in the SAA where the OMPS Nadir Profiler is so greatly affected by charged particles that it cannot be used to produce ozone profiles. Map of South Atlantic Anomaly effects on OMPS NM closed-door dark current measurements in December and November 2011, overlaid with OMPS NP SAA Flags (0 to 8) for 3/5-6/2012

13. Wavelength Scale and Ring Effect/Stray Light The EOF Covariance analysis was applied to the Nadir Mapper for the central cross-track position for the 365 nm to 380 nm wavelength ranges for parts of six orbits on 1/28/2012. The first two patterns contain 90% of the variability after removing a 3 rd order polynomial from Rad/AvgRad. The two patterns are combinations of Wavelength Scale Shift and Ring Effect/Stray Light variations. The figures on the Left of the nextslide show the sum of the first two EOF patterns (Top) and the coefficients for the first orbit (Bottom). The Top figure also has the computed variations expected from a 0.02-nm wavelength scale shift. The two curves agree very well. The pattern of the coefficients in the Bottom may be related to wavelength scale changes produces by intra-orbital variations in the optical bench temperatures. While the shifts are small, we plan to implement a correction/adjustment to improve the ozone products. The figure on the top Right shows the differences of the first two EOF patterns. Now the additional curve is a scaled set of the variations for the reciprocal average spectra. Again, the two curves agree very well. One would expect this pattern to be produced by inelastic scattering (Ring Effect) or Out-of-Band Stray light. The figure on the Bottom Right tests this by looking at the dependence of the coefficients (y-axis) with the 375-nm radiances (x-axis). The inverse relationship between the two suggest that the major source of these variations is the Ring Effect – not Stray Light. The OMPS NPP Science Team plans to exploit this signal to create UV cloud optical centroid estimates. Given the radiance levels, a 0.01 change in the figures on the Top equates to approximately a 1% variation.

14. * EOF pattern –– 0.02-nm shift * EOF pattern –– ∝ (1/Avg-poly) Wavelength Shift and Ring Effect/Stray Light 0.5%

15. Initial Measurement Residuals for the OMPS NP V8 Profile Product: The nine figures show the initial residuals for profile wavelengths [252, 274, 283, 288, 292, 298, 302, 306 and 313 nm, (a) to (i), respectively] for the V8PRO product from OMPS compared to the same product for the operational NOAA-18 and NOAA-19 SBUV/2 for the equatorial daily zonal means (20N to 20S) with 0-90W removed to avoid the SAA. The residuals are in N-values (1 N ~ 2.3%). The time period is the first six months of this year (February to May for OMPS). Notice that the residuals for OMPS, have maintained a persistent bias relative to the SBUV/2 residuals. Time series of initial V8PRO residuals for OMPS NP February through June

16. D. Rault, NASA LaRC  OMPS Limb Profiler These curtains represent the ozone profile in vertical slices through the atmosphere along the three paths shown above. They demonstrate the ability of the research retrieval algorithm for the OMPS Limb Profiler in use at the NASA Ozone PEATE. The gaps at the top in the middle of the plots occur when the satellite encounters charged particles as it passes through the South Atlantic Anomaly; these are consistent with the modeled effects. The profiles regularly extend down below 15 KM in altitude.

17. Daily Total Column Ozone map comparisons between (a) IDPS OMPS First Guess Multiple Triplet product, (b) NOAA OMPS V8 product, and (c ) NASA OMI V8.6 product for March 30, 2012. Cross-track features in OMPS products are related to the use of preliminary calibration values. (a) (b) (c) DU 100 300 500

18. February weekly-mean total column ozone as a function of the cross-track view angle for the Equatorial Pacific region defined by 20°S to 20°N Latitude, 100°W to 180°W Longitude.

19. OMPS Aerosol Index shown over VIIRS RGB image for July 4, 2012

20. Summary & Information The OMPS instruments are performing well and the retrieval algorithms are producing reasonable products. Instrument characterization and product validation are proceeding and will produce shifts in the product quality. OMPS Nadir Mapper and Nadir Profiler Products will be released at “Beta” maturity levels this week and become available at CLASS: http://www.nsof.class.noaa.gov /saa/products/search?datatype_family=OMPS OMPS Limb Profiler Products will be released starting this November through the NASA GES DISC Monitoring plots are provided at the ICVS: http://www.star.nesdis.noaa.gov /icvs/PROD/proOMPSbeta.TOZ_INCTO.php

21. Backup

22. Figures: J. Niu, NOAA/STAR (ERT) 1/26- 27/2012  331-nm Channel Radiances for the first eight orbits of OMPS Nadir Mapper measurement (end of 1/26/2012 and start of 1/27/2012). This image shows the expected range of values and variations across the orbital track and with solar zenith angles at the times of the measurements. The white circle around the North Pole is the region of polar night during the Northern Hemisphere Winter. The OMPS needs scattered sunlight to make its measurements, so there are no data there.  Total Ozone from the multiple triplet retrieval algorithm in IDPS for the same eight orbits for the first pass ozone retrieval (first guess IP product without CrIS or VIIRS information). The values show some cross track variations and are offset approximately 5- 10% from other satellite ozone products. These uncertainty levels for preliminary products are consistent with the use of prelaunch calibration parameters and tables in the initial operational system. Effective Reflectivity from the multiple triplet retrieval algorithm in IDPS for the same eight orbits. The quantity represents the UV reflectivity of the clouds and surface in each Field-of-View. Again, the range of values from bright clouds to dark open ocean scenes is as expected. Reflectivity 

23. Total Ozone Maps for OMPS INCTO, OMPS V8, OMI V8.6, and GOME-2 V8 for June 15, 2012

24. OMPS NP Solar Flux Measurements

25. Noise and Stray Light for OMPS NP Earth Radiances The scatter plot on the left compares simple three-wavelength Mg II core-to-wing ratio variations (280 nm to the average of 277 nm and 282 nm) with longer wavelength variations at 305 nm. There is no geophysical reason to expect the two to be correlated, and the exposed relationship is symptomatic of out-of- band stray light. The core average is ~0.4 of wings, so this -0.5% to 1.5% variation represents (1.0/0.4 – 1 =) 1.5 times the expected stray light variations in the wings. The % RMSR estimates on the right were computed using EOF analysis on clean data for 230 spectra. A spectral screen detected and removed one deviant value on average from each of the 120-wavelength spectra. The removal of the second EOF pattern was somewhat arbitrary as it and the third EOF may be stray light patterns. The covariance computation used a 6 th order polynomial for normalization.

26. IINCTO One-Percentile Reflectivity Cross-Track Dependence for March Cross-track View Position Black Week 1 Blue Week 2 Green Week 3 Red Week 4 |Lat|<20 Lon<-100 Reflectivity, %

27. Overview of Data Products (2/2) Total Column Ozone –Global coverage of atmospheric ozone column Operational Assimilation (Weather and UV forecast) Daily Maps (Ozone Hole/Layer monitoring) Climate Data Records (Ozone Layer assessments) –UV Effective reflectivity IP –UV Aerosol Index IP Ozone Vertical Profile –Nadir Profiler Layer amounts and mixing ratios –Mg II Solar Index –Limb Profiler Number density and mixing ratios CrIS IR Ozone –Ozone total column and profile 27

28. Schedule of Major Task Categories Pre-Launch Phase (L-24M to L) –Improve Ground-based assets operations and access –Develop Match-up and statistical analysis tools and readers –Implement and exercise forward models for radiative transfer –Create and manipulate sample, synthetic, and proxy SDR (Level 1), EDR (Level 2), and DIP data sets –Collect and exercise calibration parameters and instrument models –Implement alternative/heritage algorithms Early Orbit Check Out Phase (L to L+3M) –Check parameters and instrument behavior –Perform internal consistency checks –Provide feedback to SDR Team –Test tools and alternate algorithms with real data Intensive Cal/Val Phase (L+3M to L+24M) –Perform external comparisons to satellite products –Perform sub-orbital comparison/validation –Provide feedback to IPO and NGAS –Evaluate product applications –Begin trending and automated monitoring Transition to regular operations and long-term monitoring

29. How much data do you need? What can it tell you? How can you accentuate different effects? Internal Measurements –Dark Current and non-Linearity estimates, and Charged Particle effects Single set of Solar measurements –Goniometry, Irradiance Calibration, Wavelength Scale, SNR, Flat Fielding, Bandpass check (Comparisons to reference, contemporaneous, and high-resolution spectra) Single Orbit of Earth-view data –Wavelength Scale variations, SNR, Rough Radiance/Irradiance Calibration, Triplet/Pair consistency (Absorbing, reflectivity, and aerosol channels), Cross-track consistency Single Day –Total Ozone versus other mappers, Zonal Means, Stray Light (Profile Wavelengths), better orbital analysis, and start of performance monitoring Single Week –Cross-track consistency, Absolute calibration of reflectivity channels, calibration biases compared to other space-based mappers and profilers – transfer, and better daily analysis. Single Month –Ground based total ozone validation data points (assisted by transfer), Starting points for trending of instrument degradation and solar diffuser changes, and better weekly analysis – trending of consistency results. Single Year –Ground-based ozone profile validation, evaluation of long-term characterization, better monthly analysis, and start of ice radiance trending.