GOES-R AWG 2nd Validation Workshop 9-10 January 2014, College Park, MD

GOES-R and JPSS SST Monitoring System

Sasha Ignatov, Prasanjit Dash, Xingming Liang,Feng Xu, Yury Kihai, Xinjia Zhou

With support fromJohn Sapper, John Stroup, Boris Petrenko, Marouan Boauli

9 January 2014 GOES-R SST Validation 1

SQUAM - SST Quality Monitor www.star.nesdis.noaa.gov/sod/sst/squam/ Monitor SST Products (L2, L3, L4) for Self- and Cross-

Consistency; Validate against in situ SSTs (iQuam)

iQuam - In situ Quality Monitor www.star.nesdis.noaa.gov/sod/sst/iquam/ QC in situ SSTs, Monitor on Web, Distribute to users Input to SQUAM

MICROS - Monitoring IR Clear-sky Radiances over Oceans for SST www.star.nesdis.noaa.gov/sod/sst/micros/ Monitor Clear-sky ocean radiances for Self- and Cross-

Consistency; Validate against CRTM simulations

NOAA JPSS and GOES-R Cal/Val Tools

9 January 2014 2GOES-R SST Validation

SST Community Resources, Support JPSS and GOES-R

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Principles of NOAA SST Monitoring

9 January 2014 GOES-R SST Validation

Monitor automatically, in Near-Real Time, Globally, Online- Satellite SSTs against reference SST- Satellite sensor radiances associated with SST- Reference SSTs (in situ, L4)

Monitor GOES-R and JPSS SST products in context of other community SST products

Monitor deviations from a reference state (expected to be centered at zero, and have a narrow Gaussian distribution)

Supplement heritage VAL against in situ SST (sparse, geographically biased, suboptimal quality, not available in NRT) with global consistency checks against another reference, L4 analysis fields (global coverage, large statistics, more uniform data quality, available in NRT)

SST Monitoringin SST Quality Monitor (SQUAM)

www.star.nesdis.noaa.gov/sod/sst/squam/

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Das, et al: SST Quality Monitor. JTECH, 2010.

DAY: VIIRS L2 minus OSTIA L428 December 2013

• Deviation from Reference SST is flat & close to 0• Residual Cloud/Aerosol leakages seen as cold spots• Warm spots show areas with diurnal warming during daytime

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DAY: VIIRS L2 minus in situ SST28 December 2013

• Much fewer match-ups with in situ data than with L4 • Validation statistics may not be globally representative• Daily validation statistics may not be accurate and stable

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DAY: VIIRS L2 minus OSTIA L428 December 2013

• Shape close to Gaussian but skewed positively due to diurnal warming• Domain & Performance Stats close to expected

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DAY: VIIRS L2 minus in situ SST28 December 2013

• Shape close to Gaussian • Domain & Performance Stats better than spec

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DAY 28 December 2013 – Summary

NOBS Min/ Max Mean/ STD Med/ RSD Skew/ Kurt

117,600,000 -8.7/ +8.6 +0.29/0.60 +0.22/0.45 +1.5/ +7.9

ΔT = “VIIRS minus OSTIA” SST

9 January 2014

NOBS Min/ Max Mean/ STD Med/ RSD Skew/ Kurt

1,909 -1.5/ +2.5 +0.06/0.39 +0.09/0.32 -0.1/ +2.8

ΔT = “VIIRS minus in situ” SST

9GOES-R SST Validation

DAY STD DEV wrt. In situ SST

Outliers come from satellite and in situ data

IDPS shows larger STDalthough improved recently

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• Daily val against in situ SST is noisy due to small match-up sample & lack of global coverage• IDPS SST improved recently but has been out of family for the full 2 years of monitoring

DAY STD DEV wrt. Reynolds L4

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IDPS shows much larger STD

• IDPS SST has been out of family but improved in mid 2012. Still significantly deviates from family, but less than earlier in the mission

DAY STD DEV wrt. OSTIA L4

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IDPS shows much larger STD

• Comparison with OSTIA SST suggest the same qualitative observations as against Reynolds and in situ, although quantitatively, comparison statistics may differ

VIIRS, MODIS, and AVHRRRadiance Monitoring in MICROS

www.star.nesdis.noaa.gov/sod/sst/micros/

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Liang, Ignatov: Monitoring IR Clear-Sky Radiances over Oceans for SST. JTECH, 2011.

GOES-R SST Validation

Model minus Observation (“M-O”) Biases- M (Model) = Community Radiative Transfer Model (CRTM) simulated

TOA Brightness Temperatures (w/ Reynolds SST, GFS profiles as input)- O (Observation) = Clear-Sky sensor (AVHRR, MODIS, VIIRS) BTs

Double Differences (“DD”) for Cross-Platform Consistency

- “M” used as a “Transfer Standard”- DDs cancel out/minimize effect of systematic errors & instabilities in BTs

arising from e.g.- Errors/Instabilities in Reynolds SST & GFS- Missing aerosol- Possible systemic biases in CRTM- Updates to ACSPO algorithm

M-O Biases and Double Differences (“DD”)

)]([)]([ OMREFOMSATREFSAT

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• All AVHRRs (except N16 and Metop-B), MODISs, and VIIRS are now consistent to within ±0.1K• VIIRS Cal change 7 Mar 2012 reset BT@M15 by +0.14K – now better in family• Before 13 Sep 2012: Terra & Aqua/MODIS were biased by -0.6K (suboptimal CRTM coeffs in v2.02)• Both are back in family now, after CRTM V2.1 implemented on 13 Sep 2012• Metop–B out of family by ~+0.3 K (likely due to suboptimal CRTM coefficients in CRTM V2.1)

N16: unstable and out of family

CRTM V2.1 implemented

Metop-B: out of family

Double Differences in IR11 (VIIRS M15)

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VIIRS recalibration

GOES-R SST Validation

• All AVHRRs, MODISs and NPP/VIIRS SSTs are consistent to within ±0.1K• As a result of VIIRS Cal Change on 7 Mar 2012, VIIRS SST went out of family • Was brought back in family when new SST coefficients implemented 3 May 2012• CRTM update resulted regression SSTs more noise, and the new coefficients have been implemented

since Dec. 2012. More data is needed to understand their performance

N16: unstable and out of family

VIIRS recalibration CRTM V2.1 implemented

Double Differences in SST

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New Reg. Coeff. used

GOES-R SST Validation

In situ SST QC & Monitoring in iQuam

www.star.nesdis.noaa.gov/sod/sst/iquam/

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Xu, Ignatov: In situ SST Quality Monitor. JTECH, 2014.

GOES-R SST Validation

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In situ Quality Monitor (iQuam) performs the following functions

QC: Accurate/flexible QC of in situ SSTs, consistent with wider Meteorological and Oceanographic communities

Monitoring: Report online statistical summaries of in situ minus reference L4 SST (stratified by ships, drifters, tropical & coastal moored, ARGO floats; and individual platforms)

Data Serving: Serve QCed in situ SST data online for SST community

Objectives of in situ SST Quality Monitor

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Quality Control – Consistent with UK MO

Category Check Type of error handled Physical basis

Preprocessing Duplicate Removal

Duplicates arise from multiple transmission or data set merging

Identical space/time/ID

Plausibility Plausibility checks

Unreasonable field values Range of single fields &Relationships among them

Internal consistency

Tracking Points falling out of track Travel speed exceeds limit

Spike check Discontinuities in SST time series along track

SST gradient exceeds limit

External consistency

Reference Check

Measurements deviating far away from reference

Bayesian approach (*) (Ref. SST: Daily OI SST v2)

Mutual consistency

Cross-platform Check

Mutual verification with nearby measurements (“buddies check”)

Bayesian approach (*) based on space/time correlation of SST field (Correlation model: 2-scale SOAR, Martin et al., 2002)

(*) Lorenc and Hammon, 1988; Ingleby and Haddleston, 2007

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http://www.star.nesdis.noaa.gov/sod/sst/iquam/

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Monthly Statistical Summaries

Outliers detected by each QC check

Moments of ΔTS=Tin situ - TReynolds

Histograms of ΔTS

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Time Series of Monthly Statistics (1981-pr)

No of Platforms No of Observations

Bias in ΔTS

SD of ΔTS

ships

drifters

moorings

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Monitoring individual platforms

List of platforms & individual statistics

Error Rate History

Time Series of ΔTS

Monthly Trajectory

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Data for Download

Last monthly file updated in NRT every 6hrs. Initial QC performed on the fly. Final QC requires ~7 days.

QC’ed data in HDF format available for download (1981-pr)

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Status of NOAA SST Monitoring

Well established for polar products AVHHR (NOAA, NAVO, EUMETSAT) MODIS-Terra, MODIS-Aqua (NOAA) VIIRS (NOAA)

Progress made towards Monitoring Geo products Some elements of SQUAM and MICROS web design in place Prototyped using MSG SEVIRI (NOAA) Not linked to SQUAM and MICROS main pages yet

Future work

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Polar Products Bring into SQUAM remaining community SST products -

MOD28/MYD28 and (A)ATSR Update and unify functionality

Geo products Complete development of Geo functionality in SQUAM and MICROS Set up match-up processing with iQuam in situ data Link to main SQUAM and MICROS pages

Get ready for GOES-R launch!