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6 Pre-decisional / For Planning Purposes Only7/5/2010 ParameterTime scaleVariableRI Error, k=2 (%) OffsetmonthlyAll Data≤ 1.2 GainmonthlyAll Data≤ 1.2 SRF DegradationseasonallyScene Type (clro)≤ 0.7 Non-LinearityValidation Annually, RI Error 0.3%(k=2) Sensitivity to PolarizationNot Sensitive, Validation Annually, RI Error 0.3%(k=2)  Goals are set at noise level ≈ 1% (sources: instrument + data matching )  RI error ≤ 0.3% (k=2) over auto-correlation time period = 18 months 1) CLARREO Inter-Calibration Goal: CERES 2) CLARREO Inter-Calibration Goal: VIIRS ParameterTime scaleVariableRI Error, k=2 (%) Baseline OffsetmonthlyVZA(7), DOP, HAM≤ 1.2 Baseline GainmonthlyVZA(7), DOP, HAM≤ 1.2 Sensitivity to PolarizationseasonallyVZA(7), DOP, χ (9), HAM≤ 0.7 SRF CW ShiftValidation Annually, RI Error 0.3 %(k=2) Non-LinearityValidation Annually, RI Error 0.3%(k=2)

7 Pre-decisional / For Planning Purposes Only7/5/2010 CERES RSR Degradation: α = λ =0.7 μ m) Plots:  Top: CERES – CLARREO difference versus CLARREO signals (%).  Middle: CERES – CLARREO difference versus CLARREO signals (%) with 1% matching noise.  Bottom: Relative difference between CLARREO and CERES signals with noise reduced by averaging. FIT RESULTS: SceneOFFSET (Wm -2 sr -1 ) GAIN (%) CLRO ± ± 0.18 MCLD0.021 ± ± 0.10 * CLRO: Offset error (2σ) = 0.21% * MCLD: Offset error (2σ) = 0.10%

8 Pre-decisional / For Planning Purposes Only7/5/2010 Assuming 1% space/time/angles data matching (Wielicki et al., IGARSS 2008), only linear case differences with CLARREO (offset and gain only), the reference inter-calibration error should be reduced as sqrt(N) as number of samples decreases. Error versus N samples: N SamplesRI Error (%, k=2) 16, , , , ,  From simulation using SCIAMACHY spectral data (clear-sky ocean case)

9 Pre-decisional / For Planning Purposes Only7/5/2010  Based on near-nadir CERES/MODIS/Aqua data (VZA < 10 o, 20 km FOV).  SZA < 75 o.  Distribution in latitude similar to CLARREO-JPSS inter-calibration sampling (Studies by Speth & Roithmayr) 2005 CERES SSF, Fraction of Clear - Sky: Surface TypeTropic Clear (%) Non-Tropic Clear (%) Ocean Evergreen Forest Deciduous Forest Shrubs & Crops Dark Desert Bright Desert Snow CLEAR SKY: Cloud fraction < 0.1%.

10 Pre-decisional / For Planning Purposes Only7/5/2010 Relative fraction of data (%) with DOP(490 nm) < X (fractional): DOP Range< 0.05< 0.1< 0.2< 0.3< 0.4< 0.5< 0.75 Global Data (%) Relative fraction of data (%) with DOP(670 nm) < X (fractional): DOP Range< 0.05< 0.1< 0.2< 0.3< 0.4< 0.5< 0.75 Global Data (%) Relative fraction of data (%) with DOP(865 nm) < X (fractional): DOP Range< 0.05< 0.1< 0.2< 0.3< 0.40< 0.5< 0.75 Global Data (%)  PARASOL Level-1 data: 12 days of 2006, accuracy 2-3%. (1 day per month, “cross-track” sampling)  Distribution in latitude similar to CLARREO-JPSS RI sampling.  SZA < 75 o. DOP = linear degree of polarization

11 Pre-decisional / For Planning Purposes Only7/5/2010 N Samples CERESN Samples VIIRSRI Errors, k=2 (%) 16,000448, ,000224, ,000112, ,00056, ,00028, , , ,  CERES RI: All collected data together.  For VIIRS RI: Factor 2 for DOP ≤ 0.05 (670 nm), factor 7 for VZA, and factor 2 for HAM sides. Total = factor 28.

12 Pre-decisional / For Planning Purposes Only7/5/2010 N Samples (CERES)N Samples (VIIRS)RI Errors, k=2 (%) 480, M , M , M , M0.3 30, M , M0.6 (0.7) 7, M0.85 3, M1.2  CERES RI: Factor of 30 for clear-sky ocean scene (3% of global sampling).  For VIIRS RI: factor 10 for DOP = 0.2 – 0.4 (670 nm), 7 for VZA, 9 for χ, and factor of 2 for HAM side. Total = factor of 1,260.

13 Pre-decisional / For Planning Purposes Only7/5/2010 DAC-4 CLARREO Observatory Configuration: Both Spectrometers + GNSS-RO (CLARREO Engineering Team, January 2010) RSS located on nadir deck. No bus maneuver required for CLARREO RSS RI operations. Double-axis (2D) gimbal to provide angular data matching in both yaw and roll angles.

14 Pre-decisional / For Planning Purposes Only7/5/2010 DAC-5 CLARREO Observatory Configuration: RSS + GNSS-RO (CLARREO Engineering Team, Current Baseline)  Nadir (+Z) DAC-5 concepts require “yaw” or +Z rotation by the S/C bus. Single axis gimbal provides for “Roll” or cross-track pointing OFF Nadir +55 o OFF Nadir -55 o Angular matching: - “Yaw” maneuver allows to match azimuth angle. - Gimbal “Roll” allows to match scan/VZA angle

15 Pre-decisional / For Planning Purposes Only7/5/2010 Orbital Simulations (Carlos Roithmayr & Paul Speth) DAC-5 CLARREO RSS RI Operations option: 1) S/C Yaw (azimuth angle) q1 match = constant (matching within 0.5 o ) 2) Continuous Gimbal Roll (scan angle) q2 match = q2(t) Goal: Time/space/angle matching to obtain ensemble of samples with data matching noise ≤ 1% Wielicki et al., IGARSS 2008 Matching requirements: 5 min within JPSS passing Viewing Zenith Angle match within 1.4°, SZA < 75 o At least 10 km effective width of CLARREO swath CLARREO-1 RS boresight locations matching JPSS cross-track data over one year time period

16 Pre-decisional / For Planning Purposes Only7/5/2010 Geometry of RI Event Diagrams for DAC-5 Operation Option Projection in JPSS cross-track plane Top view Note: All matched data (red parallelogram) is aligned with JPSS cross-track direction

17 Pre-decisional / For Planning Purposes Only7/5/2010 Orbital Simulations: CLARREO-1 (2017) and 2 (2020) with JPSS (Carlos Roithmayr & Paul Speth) CLARREO-1 Mission START: Autumn Equinox, P90 orbit, Ω = 0 o (orbital plane parallel to Earth-Sun direction) CLARREO-2 Mission START: Autumn Equinox, P90 orbit, Ω = 90 o (orbital plane perpendicular to Earth- Sun direction). Inter-Calibration Time per Day: CLARREO RSS is matched to JPSS in 833 km sun synch orbit. CLARREO Orbits should be optimized: Study is in progress… * Ω = right ascension of the ascending node, or RAAN

18 Pre-decisional / For Planning Purposes Only7/5/2010 Orbital Simulations: CLARREO-1 (2017) with JPSS and METOP (Carlos Roithmayr & Paul Speth) RI Events on : no overlap. Inter-Calibration Operation Schedule: Taking into account time for yaw maneuver 134 RI JPSS/METOP events overlap over one year time period (out of total 1,330 events). Yaw Time = ×|q1| ×|q1| 2 CLARREO-1 Mission START: Autumn Equinox, P90 orbit, Ω = 0 o (orbital plane parallel to Earth-Sun direction) Inter-Calibration Time per Day: CLARREO RSS is matched to JPSS in 1:30 pm (top); and METOP in 9:30 a.m. sun synch orbit. Both SS target orbits are at 833 km altitude. Pre-decisional / For Planning Purposes Only7/5/2010

19 Pre-decisional / For Planning Purposes Only7/5/2010 Orbital Simulations: RI and Operation Time (Carlos Roithmayr & Paul Speth) DAC-5 CLARREO RSS Bus: Yaw Time = ×|q1| ×|q1| 2 CLARREO-1 Inter-Calibration time: Time of RI Event with all data matching restrictions (space/time/angles) CLARREO-1 Operation time: Inter-Calibration time + 2 Yaw Time intervals Schedule of this Operation Time for CLARREO-1 RI with JPSS and METOP is generated. Examples of Scheduling Priorities: - RI Time interval (minimum duration/number of samples); - RI Time versus Operation time (efficiency); - Tropics versus polar regions (clear-sky ocean scene), oversampling in high latitudes; - RI versus Solar/Lunar calibration operations (potential scheduling conflict); - Minimization of RI impact on the benchmark (D. Doelling Group).

20 Pre-decisional / For Planning Purposes Only7/5/2010 Sampling Estimate and Constrains

21 Pre-decisional / For Planning Purposes Only7/5/2010 Sampling Summary for CLARREO-1/JPSS Monthly (top) and seasonal (bottom) sampling with VIIRS and CERES Red Lines: Required number of samples for RI seasonal error contribution 0.7% (k=2) Red Errors: Required number of samples for RI monthly error contribution 1.2% (k=2) WARNING: The required number of RI samples is derived under assumption of uniform sampling distribution in relevant parameters to VIIRS sensitivity to polarization: DOP and polarization angle.  

22 Pre-decisional / For Planning Purposes Only7/5/2010 Distribution of DOP, PARASOL Data, Average on 1 o ×1 o grid, fractional units, “cross-track” mode  λ = 490 nm * RAZ < 90 o is to the left of the ground track * RAZ > 90 o is to the right of the ground track  λ = 670 nm  λ = 865 nm * For cross-track data tacking mode DOP distribution is has systematic dependence on viewing geometry.

23 Pre-decisional / For Planning Purposes Only7/5/2010 Distributions of DOP and Polarization Angle PARASOL Data, 12 days 2006, simulated cross-track RI sampling - if (χ < 0) χ mod = 180 o + χ - λ = 490 nm Forward Scatter Back Scatter * Color scale = Relative sampling

24 Pre-decisional / For Planning Purposes Only7/5/2010 Possible RI of VIIRS on detector-by-detector basis, Diagram, Sampling plots, more studies - Angular matching within 1.4 o VZA - Spatial matching: about 300 pixels VIIRS and 400 CLARREO (2 consecutive frames) - Study needed to estimate spatial matching noise (using MODIS 250 m resolution data) - CLARREO reading data rate could be increased (to reduce spatial noise) Note: VIIRS scans cross-track with 16 detectors/band in a-track direction every 1.5 sec or every 11 km. 11 km swath is built by 16 detectors.

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26 Pre-decisional / For Planning Purposes Only7/5/2010 Prototype PDM and its STD, PARASOL Data (12 days of 2006, 1 per month): A-Train Orbit Cross-Track Sampling (PARASOL 12 days of 2006):

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28 Pre-decisional / For Planning Purposes Only7/5/2010 CLARREO RS Instrument Noise Contribution

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31 Pre-decisional / For Planning Purposes Only7/5/2010 CLARREO RS spectrometer baseline:  Radiance measurements with accuracy 0.3%(2 σ ) for the time of the mission, uncertainty due to sensitivity to polarization included.  Wavelength range from 320 to 2300 nm.  Spectral sampling = 4 nm.  Spatial resolution 0.5×0.5 km (65% of signal).  Pointing ability (gimbal or S/C).  Polarization Distribution Models to provide polarization information (both DOP and χ ).  CLARREO RS Inter-Calibration Event: orbits crossing of CLARREO with sensor to be calibrated that allows time/angle/ space matching  CLARREO RS Swath: 100 km (nadir)  CLARREO/Solar Inter-Calibration Sample: area of 10 km scale for reduction of spatial matching noise to 1% level. (Wielicki et al., IGARSS 2008)  CLARREO RS Pixel: 0.5×0.5 km observed area (65% of signal). Study needed to quantify sampling Geometry (MODIS data 250 m resolution) Pre-decisional / For Planning Purposes Only7/5/

32 Pre-decisional / For Planning Purposes Only7/5/2010 MonthN Samples CERES RI Error k=2 (%) N Samples VIIRS RI Error k=2 (%) 1September48.5 K≤ M≤ 0.1 2October1.4 K M0.15 3November0.3 K M0.2 4December 3.1 K M0.1 5January16.8 K M≤ 0.1 6February54.1 K≤ M≤ 0.1 7March57.1 K≤ M≤ 0.1 8April14.5 K M≤ 0.1 9May2.9 K M0.1 10June2.9 K M0.1 11July6.2 K M≤ August34.8 K≤ M≤ 0.1 Estimated Monthly N samples for CERES and VIIRS: Average error over one year period is 0.%(k=2) for CERES and 0.%(k=2) for VIIRS.

33 Pre-decisional / For Planning Purposes Only7/5/2010 SeasonN SamplesRI Errors, k=2 (%) S150 K0.4 S274 K0.3 S373 K0.3 S443 K0.4 Seasonal N samples for CERES: SeasonN SamplesRI Errors, k=2 (%) S16.3 M0.2 S29.4 M0.15 S39.5 M0.15 S45.7 M0.2 Seasonal N samples for VIIRS: