Integrated Mission Review 28Jan10 8Jan10: N - 1Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

Reflected Solar Science Summary

Integrated Mission Review 28Jan10 8Jan10: N - 2Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Follow same philosophy as yesterday’s IR discussion• Review

– RS science related to benchmarking and reference intercalibration– How to achieve SI traceability– Technical readiness– Requirements– Way forward to writing the RS science summary

Reflected Solar Science Studies summary overview

RS discussion goals

Integrated Mission Review 28Jan10 8Jan10: N - 3Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Reflected solar fingerprinting studies: Clear-sky and all-sky B. Collins/D. Feldman (30 min)

• Reflected solar radiative kernels & applications to solar fingerprintingZ. Jin (30 min)

• Truths status K. Thome for N. Fox (30 min)• D. Young (30 min)

– Break 10:15-10:45• Reflected solar reference intercalibration method and sampling

C. Lukashin (45 min)• RS orbit sampling D. Doelling (30 min)

– Lunch 12:00-13:30• Summary of APS on CLARREO Study & review for NASA HQ • Achieving SI traceability in orbit K. Thome (30 min)

– Break 14:30-15:00• Reflected solar instrument requirements, design, traceability, technical readiness,

NIST activities K. Thome (60 min)• Science value matrix B. Wielicki (>45 min)

– Adjourn 17:15

Reflected Solar Science Studies summary overview

Agenda summary

Integrated Mission Review 28Jan10 8Jan10: N - 4Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Include surface BRDF model (spatial and temporal) for RS benchmark studies • Completion of OSSE studies

– Extend to all sky, sun-synch case– Extend to other orbits

• Determine difference in globally-averaged zonal, hemispheric-directional reflectance between sun-synchronous orbit and precessing orbit

– Nadir view– Annual– Monthly– Goal: Evaluate whether interannual variability varies with orbit selection

• Completion of science requirements reports for RS sensor by May 29 (even if only in rough form)

• Mission concept study including IR precessing orbit and RS sun-synchronous

Integrated Mission Review 28Jan10 8Jan10: N - 5Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Climate OSSE study– Modeling effort for a sun-synchronous case at 1:30 pm crossing has been completed

Surface BRDF has been included Method to account for land-surface changes with time (snow and ice cover) Consistency checks give confidence that model is being run properly

– Future work Fingerprinting/spectral projection

» Signatures of gases and aerosols are tough to pull out except for H2O» Clouds appear to be more straightforward to pull out

Alternate orbits Pan-spectral techniques

• Fingerprinting work– Reflectance better than radiance since normalization allows spectral features to be

drawn out.– Developed kernels from currently-available data sets– Success of kernel-based approach demonstrated on the test cases

Perturbing kernels with errors lead to similar results but with more uncertainty in the results

Knowing the cloud fraction in the retrievals reduces uncertainties in other retrievals

Summary of RS talks

Integrated Mission Review 28Jan10 8Jan10: N - 6Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Intercalibration– Understand number of samples needed to calibrate other sensors to 0.3% accuracy

based on factors including Monthly gain and offset and seasonal polarization sensitivity determination Time scales and autocorrelation length means individual intercal error can be 1.2%

– Noise simulation shows current SNR requirements are sufficient to do the reference intercalibration

– Gaps in the ability to sample certain polarization angles and degrees of polarization are not an issue since VIIRS-like sensor will also not sample these combintaions

• Sampling and orbital configuration evaluation– CERES data sets normalize the geo-stationary fluxes to fill temporal gaps– Convert fluxes to radiances using CERES angular directional models– Trends identified beyond natural variability with 2 sensors in precessing orbit

Depends on spatial averaging scale Single sun-synchronous is slightly better than single 90-degree Two sun-syncs not as good 2 precessing for annual sampling for 10deg average Can't get at regional trends with single platform

– Further studies to evaluate impact of intercalibration and solar/lunar calibration Intercalibration does not occur randomly Early look shows degradation is not significant but need further quantification

Summary of RS talks

Integrated Mission Review 28Jan10 8Jan10: N - 7Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• SI traceability– Improved understanding of methods needed to achieve the 0.3% accuracy

requirement– Laboratory work has demonstrated the capabilities needed– Exist multiple approaches to take laboratory capability to orbit

Detector-based Source-based Sensor-model methodology

– CLARREO will rely on a source-based method (sun) with sensor model to transfer laboratory calibration to orbit

• RS instrument overview– Current design going into MCR will be a two-box spectrometer approach

Risk of two-box approach predominantly in characterization/calibration Mass and cost meet DAC-5 study guidelines

– Design meets requirements Better quantification of accuracy error budget required Science summary will communicate requirements to community

Integrated Mission Review 28Jan10 8Jan10: N - 8Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Draft outline of RS Science report follows format of Bruce’s input to TRUTHS proposal

• Science Requirements/Value (science & policy)• Science Value and Mission Requirements

–  Background– Accuracy required for decadal change observations/rationale– Uncertainty in climate sensitivity dominated by uncertainty in cloud

feedback (directly related to decadal changes in cloud radiative forcing)– IPCC Report and expected trends support accuracy requirement –

“Back of Envelope Calculations”– Ratio of accuracy of actual observing system relative to perfect climate

observing system – Sampling results/Errors in observing system relative to natural

variability Natural variability strong function of time/space scale Dependence of trend accuracy on CLARREO calibration accuracy

Science summaries

Integrated Mission Review 28Jan10 8Jan10: N - 9Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Reference Intercalibration– Background– Matching spectral response to the instrument being calibrated– Time/Space/Angle matching of TRUTHS and the instrument being calibrated– Determining Polarization Dependence of the Instrument Being Calibrated– Determining Spectral Response Change of Broadband Instruments– Determining Orbits and Sampling Required for Reference Intercalibration

• Nadir Reflectance Spectral Climate Change Benchmarks– Optical fingerprinting background – Optical fingerprinting as applied to reflected solar spectra– Discussion of radiative kernel method– Results

• Calibration approaches– SI traceability– Error budgets

• Technical approach of the instrument– Satisfaction of Level 1 & 2 requirements– Risk assessment and mitigations– TRLs

Science summary outline

Integrated Mission Review 28Jan10 8Jan10: N - 10Use or disclosure of the data contained on this sheet is subject to the restrictions on the IMR cover page

• Preliminary research currently going on– Collecting relevant publications and science reports– Identify probable questions from review boards and science

community– Request updated science reports and relevant publications from

science team (7/26 deadline for receipt of information)• Finalize outline over next week

– Will solicit comments from subset of science team– Meeting with CLARREO project on July 23

• Writing of document– First draft released for comment August 6– Comments from subset of science team due August 13– Revision, submission, formatting

• Document delivered Aug. 30

Science summary schedule