CrIS SDR Calibration and Cross-sensor Comparisons

Yong Han NOAA Center for Satellite Applications and Research, College Park, MD, USA

and CrIS SDR Science Team

ITSC-19 March 25 – April 1, 2014 Jeju Island, South Korea

1

Outline

• CrIS SDR Science Team

• Data processing and Cal/Val process

• SDR product quality and calibration uncertainties

• Cross-sensor comparisons

• Summary

2

SDR: Sensor Data Record

JPSS CrIS SDR Science Team member & Cal/Val Process

• Early Orbit Checkout (EOC), 18 January – 23 February 2012 • Intensive Calibration and Validation (ICV), 23 February 2012 – 20 December 2013 • Long-term Monitoring (LTM), remaining NPP mission

3

Organization PI NOAA Center for Satellite Applications & Research (NOAA/STAR) Yong Han

University of Wisconsin (UW) Hank Revercomb

University of Maryland Baltimore County (UMBC) Larrabee Strow

Space Dynamics Laboratory/Utah State University (SDL) Deron Scott

Massachusetts Institute of Technology/Lincoln Labs (MIT/LL) Dan Mooney

Northrop Grumman Aerospace Systems Degui Gu

Exelis-ITT Mike Cromp

NASA Dave Johnson

Raytheon Wael Ibrahim

CrIS SDR calibration and validation (Cal/Val) team members (Subject Matter Experts):

CrIS SDR Validation phases:

CrIS System

4

Pre-Process

IGM to Spectrum

FFT

FCEHandling

NonlinearityCorrection

RadiometricCalibration

PostCalibration

BPF

SpectralResample

ILSCorrection

Geo-location

CMO Operation

SDR

Science RDR

CrIS instrument provides interferograms & calibration data

Interferogram

Ground SDR Software

LW band

MW band

SW band

S-NPP

CrIS

Radi

ance

Spe

ctra

SDR Product

SDR

CrIS Spectral Parameters

5

Simulated CrIS (unapodized), IASI and AIRS spectra

Band Spectral Range (cm-1)

Normal Mode Full Resolution Mode*

Resolution (cm-1) MPD (cm) Resolution

(cm-1) MPD (cm)

LW 650-1095 0.625 0.8 0.625 0.8

MW 1210-1750 1.25 0.4 0.625 0.8

SW 2155-2550 2.5 0.2 0.625 0.8

* NOAA intends to operate CrIS in full spectral resolution (FSR) mode in near future

IASI

AIRS – 40 K

CrIS_full-resolution – 80 K

CrIS_Norm – 120 K

CrIS FOV, FOR and Scan

6

Ascending Descending

V

(A)North

A

A - ascending Nadir FOV footprints

FOR FOV

• Each scan has 30 Earth view Field of Regards (FORs) • Each FOR has 9 Field of Views (FOVs)

B - descending

B

CrIS SDR CalVal Milestones

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12/20/2013 Time 01/31/2013

Provisional status Beta status

First SDR product

Validated status

Calibration algorithm and

coefficient updates

02/20/2014

04/19/2012

04/02/2012 Intensive Calibration & Validation (ICV)

• Major ICV activities – SDR algorithm and software improvement – CrIS performance characterization – Radiometric CalVal – Spectral CalVal – Geolocation CalVal – CrIS instrument and SDR trending and monitoring

SDR validated in three stages: Beta, Provisional, and Validated

CrIS Data and SDR Software Available to Public

• CrIS Raw Data Records (RDRs) and Sensor Data Records (SDRs) – RDRs: interferogram measurements and calibration data (inputs of the SDR

software) – SDR: radiance products (outputs of the SDR software) – Data available at http://www.nsof.class.noaa.gov/saa/products/welcome

• CrIS SDR software (ADL) – CrIS SDR software is a component of the Algorithm Development Library (ADL),

which runs on Linux as well as some other computing platforms – ADL shares the same processing software as the operational software that runs

on the Interface Data Processing Segment (IDPS) – ADL software package available at https://jpss-adl-

wiki.ssec.wisc.edu/mediawiki/index.php/ADL_Algorithm_Development_Library

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Example of SDR Product Items

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Radiance (900 cm-1) Overall SDR quality flag (Blue – good)

http://www.star.nesdis.noaa.gov/icvs/status_NPP_CrIS.php

http://www.star.nesdis.noaa.gov/jpss/documents/UserGuides/CrIS_SDR_Users_Guide_1p0_TBD.pdf

CrIS SDR User’s Guide:

CrIS data monitoring website:

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CrIS Data Quality and Calibration Uncertainty Estimates

CrIS Data Quality

• No ice contamination on detector so far

• No significant South Atlantic Anomaly (SAA) impact

• No Fringe Count Error (FCE) so far

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LW 99.9817% MW 99.9817% SW 99.9816%

Long Wave

Mid Wave

Short Wave

Daily Percentage of Invalid interferogram measurements

Daily occurrence of Good SDR spectra

Mainly due to sun-glint saturation

10-3

Han et al. 2013, JGR

CrIS Noise (NEdN)

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The noise levels substantially better than specification

Radi

ance

(mW

/m2 s

r cm

-1)

Specification

Stable NEdN Jan 2012 to Feb 2014

Zavyalov et al. 2013, JGR

Spectral Calibration Accuracy

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Radiance error caused by 3 ppm frequency error

1000 2000 1500 2500 Wavenumber (cm-1)

Spectral calibration accuracy (all FOVs & all bands):

< 3 ppm

BT (K

)

Frequency calibration error

Strow et al. 2013, JGR

Earth-rotation Doppler Effect

14 (Chen, et al. 2013, AO)

Black – ascending, Green – descending, Red - theory

FOR(i) relative to FOR(31-i) frequency shift near Equator

FOR1 relative to FOR30 frequency shift as a function of latitude

• Doppler frequency shift up to 1.25 ppm detected, which matches to the theory •The shift is small and is not corrected

Radiometric Uncertainty (RU)

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BT u

ncer

tain

ty

Uncertainty specification @287K blackbody

1.7 K

0.39 K

Distribution of 3-sigma RU for one orbit of data

RU u

ncer

tain

ty (K

) 3-

sigm

a RU

(K)

3-sigma specification

1-sigma specification

RU better than spec by approximately a factor 4

Tobin et al. 2013, JGR

Geolocation Accuracy Assessed with VIIRS

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Since Provisional Review Meeting

VIIRS geolocation side A to side B switch

All FOVs From FOR 14 to 15

Pixel geolocation accuracy: < 0.4 km nadir < 1.3 km (Zenith angle < 30o)

Due to VIIRS “bowtie deletion”, this method does not apply to pixels with zenith angle larger than 30o

VIIRS I5 band data (350m spatial resolution) are used to assess CrIS geolocation accuracy

Nadir geolocation accuracy time series

0.354 ±0.047 km cross-track direction 0.209 ± 0.082 km in-track direction

Wang et al. 2013, JGR

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Cross-sensor Comparisons

Hot Scene CrIS/VIIRS Comparison

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Australian Desert, Jan. 29, 2013

Good agreement in the entire region (no data points were excluded)

12.01 μm

4.05 μm

Hot scene

(see backup slides for CrIS – VIIRS figures)

Cold Scene CrIS/VIIRS Comparison

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• Good agreement in the LW channel • VIIRS M13 lost sensitivity below 200 K (no data points were excluded)

4.05 μm

12.01 μm Deep Convective Clouds near Solomon Islands Feb. 5, 2013

Cold scene

Time Series of CrIS/VIIRS Comparison

20 CrIS/VIIRS daily mean difference are < 0.1 K and trends are < 10 mk/yr

From D. Tobin, UW

CrIS/AIRS SNO Comparisons

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North SNO (164 samples)

South SNO (161 samples)

Red: CrIS; Black: AIRS

From L. Wang, NOAA/STAR SNO time difference < 2 min Distance difference < 6.5 km

CrIS/AIRS SNO Time series at 899.97 cm-1

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Blue: South SNO Red: North SNO

From L. Wang, NOAA/STAR

CrIS/IASI(Metop-A) SNO Results from Feb. to Dec. 2013

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North Pole

South Pole (1041) North Pole (945)

Bias: CrIS-IASI

STDEV: CrIS-IASI

Bias: CrIS-IASI

STDEV: CrIS-IASI

Wavenumber (cm-1) Wavenumber (cm-1) From L. Wang, NOAA/STAR

SNO time difference < 2 min Distance difference < 6.5 km

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South Pole (783) North Pole (774)

Bias: CrIS-IASI

STDEV: CrIS-IASI

Bias: CrIS-IASI

STDEV: CrIS-IASI

CrIS/IASI(Metop-B) SNO Results from Feb. to Dec. 2013

Wavenumber (cm-1) Wavenumber (cm-1)

SNO time difference < 2 min Distance difference < 6.5 km

Preparing for Full Spectral Resolution Mode Operation • S-NPP CrIS has so far turned on the FSR mode three times for testing • Preparation is ongoing for FSR mode operation some time this year

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FSR MW band

FSR SW band

CrIS-FSR/IASI SNO Comparisons Black – CrIS current operation

From Y. Chen, NOAA/STAR Time difference < 2 min Distance difference < 6.5 km

References (JGR Special Issue)

• Han, Y., et al. (2013), Suomi NPP CrIS measurements, sensor data record algorithm, calibration and validation activities, and record data quality, J. Geophys. Res. Atmos., 118, doi:10.1002/2013JD020344

• Tobin, D., et al. (2013), Suomi-NPP CrIS radiometric calibration uncertainty, J. Geophys. Res. Atmos., 118, 10,589–10,600, doi:10.1002/jgrd.50809

• Strow, L. L., H. Motteler, D. Tobin, H. Revercomb, S. Hannon, H. Buijs, J. Predina, L. Suwinski, and R. Glumb (2013), Spectral calibration and validation of the Cross‒track Infrared Sounder (CrIS) on the Suomi NPP satellite, J. Geophys. Res. Atmos., 118, doi:10.1002/2013JD020480.

• Zavyalov, V., M. Esplin, D. Scott, B. Esplin, G. Bingham, E. Hoffman, C. Lietzke, J. Predina, R. Frain, L. Suwinski, Y. Han, C. Major, B. Graham, L. Phillips (2013), Noise performance of the CrIS instrument, J. Geophys. Res., doi: 10.1002/2013JD020457

• Wang, L., D. A. Tremblay, Y. Han, M. Esplin, D. E. Hagan, J. Predina, L. Suwinski, X. Jin, and Y. Chen (2013), Geolocation assessment for CrIS sensor data records, J. Geophys. Res. Atmos., 118, doi:10.1002/2013JD020376.

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Summary

• The CrIS instrument has been working very well and stable since the beginning of the NPP mission

• CrIS SDR product has been validated, which meets the requirements with large margin

• Instrument performance and SDR calibration/validation are well characterized and documented

• The differences between CrIS and IASI/AIRS/VIIRS are in general within 0.1-0.2 K

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Backup Slides

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IASI/CrIS vs. VIIRS M15

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New a2

New a2

Metop-A

Metop-B

Old a2

Old a2

CrIS-VIIRS IASI-VIIRS

New a2: updated nonlinearity correction coefficients used in operation after Feb. 20, 2014 Old a2: nonlinearity correction coefficients used before Feb. 20, 2014

IASI/CrIS vs. VIIRS M16

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New a2

New a2

Metop-A

Metop-B

Old a2

Old a2

CrIS-VIIRS IASI-VIIRS

New a2: updated nonlinearity correction coefficients used in operation after Feb. 20, 2014 Old a2: nonlinearity correction coefficients used before Feb. 20, 2014