Introduction of the new Suomi-NPP VIIRS Aerosol Products

Jingfeng Huang1,2, Ho-Chun Huang1,2 Istvan Laszlo2, Shobha Kondragunta2

Hongqing Liu2,3, Lorraine Remer4, Hai Zhang2,3

1 CICS-MD/ESSIC/UMD 2 NOAA/NESDIS/STAR 3 I. M. Systems Group, Inc. 4 JCET/UMBC

VIIRS Aerosol Cal/Val Team

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Name Organization Major Task Kurt F. Brueske IIS/Raytheon Code testing support within IDPS

Ashley N. Griffin PRAXIS, INC/NASA JAM

Brent Holben NASA/GSFC AERONET observations for validation work

Robert Holz UW/CIMSS Product validation and science team support

Nai-Yung C. Hsu NASA/GSFC Deep-blue algorithm development

Ho-Chun Huang UMD/CICS SM algorithm development and product validation

Jingfeng Huang UMD/CICS AOT Algorithm development and product validation

Edward J. Hyer NRL Product validation, assimilation activities

John M. Jackson NGAS VIIRS cal/val activities, liaison to SDR team

Shobha Kondragunta NOAA/NESDIS Co-lead Istvan Laszlo NOAA/NESDIS Co-lead Hongqing Liu IMSG/NOAA Visualization, algorithm development, validation

Min M. Oo UW/CIMSS Cal/Val with collocated MODIS data

Lorraine A. Remer UMBC Algorithm development, ATBD, liason to VCM

Andrew M. Sayer NASA/GESTAR Deep-blue algorithm development

Hai Zhang IMSG/NOAA Algorithm coding, validation within IDEA

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Suomi-NPP satellite launched 28 October 2011

Major Event Date UTC

NPP Launch 10/28/2012 9:48

First vis/refl. Image 11/21/2012 16:04

First IR/TIR image 1/19/2012 6:20

Rename NPP 1/25/2012

Operational Code Update Date UTC

MX5.0/5.1 12/09/2011

MX5.2 2/1/2012 15:36

MX5.3 4/2/2012 18:21

MX6.0/6.1/6.2 8/9/2012 16:18

MX6.3/6.4 10/15/2012 15:19

MX6.5 11/27/2012 14:58

MX6.6 2/28/2013 18:45

MX6.7 3/14/2013 19:48

MX7.0/7.1 7/10/2013 16:37

MX7.2 7/20/2013 20:36

MX8.0 11/15/2013

MX8.1 1/24/2014

The VIIRS operational algorithm, not only aerosol, keeps evolving over time …

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How satellite aerosol retrieval works?

TOA Reflectance

Surface Reflectance

Aerosol Optical Thickness

Overview of VIIRS Aerosol Data Products

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Parameter Name Units Horizontal Cell Size (HCS) at Nadir

Comments

Aerosol Optical Thickness (AOT)

Dimensionless 6 km (EDR) 0.75 km (IP)

Retrieved globally during daylight except areas of clouds and bright surfaces. Reported at eleven wavelengths ranging from 0.412-2.25 μm.

Aerosol Particle Size Parameter (APSP) [Ångström Exponent, AE ]

Dimensionless 6 km (EDR) 0.75 km (IP)

Reported as Ångström Exponent calculated from optical depths at pairs of wavelengths. Only proxy, not a true measure of size.

Suspended Matter (SM)

Dimensionless (except, smoke concentration in µg/m3)

0.75 km Type of aerosol (ash, dust, smoke, sea salt, unknown, none) for moderate to heavy aerosol loading, for AOT larger than threshold.

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Jackson, J. M., H. Liu, I. Laszlo, S. Kondragunta, L. A. Remer., J. Huang., H.-C. Huang, 2013, Suomi-NPP VIIRS Aerosol Algorithms and Data Products, J. Geophys. Res., IN-PRESS.

Liu, H., L. A. Remer., J. Huang., H.-C. Huang., S. Kondragunta, I. Laszlo, M. Oo, J. M. Jackson, 2013, Preliminary

Evaluation of Suomi-NPP VIIRS Aerosol Optical Thickness, J. Geophys. Res., revision submitted.

AOT & APSP Product Timeline

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Initial instrument check out;

Tuning cloud mask parameters

Beta status Error Beta status

Provisional status

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28 Oct 2011 2 May 2012 15 Oct 2012

28 Nov 2012

23 Jan 2013

Red periods: Product is not available to public, or product should not be used.

Blue periods: Product is available to public, but it should be used with caution, known problems, frequent changes.

Green period: Product is available to public; users are encouraged to evaluate.

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Daily global mean AOT550 and Standard Deviation

Processing error 10/15-11/27/2012 PCT update on 01/22/2013

Period of May 2, 2012 – September 1, 2013. A processing error affected the VIIRS retrievals during the period of October 15, 2012 – November 27, 2012, leading to the abnormally high AOT550. Update of the processing coefficient table (PCT) on January 22, 2013 brought the land VIIRS AOT550 close to the MODIS retrievals.

Seasonal Variability

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JJA: dust over Atl. & AP; smoke over Southern Africa

SON: smoke over Amazon; smoke over Maritime Continent

DJF: dust & smoke over Central Africa

MAM: Smoke over Southeast Asia; dust transpacific

Monthly AOT Animation

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Global AOT: VIIRS vs. MODIS

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Global maps of averaged VIIRS AOT550 (a,b), Aqua MODIS AOT550 (c,d), VIIRS minus MODIS (e,f), and VIIRS minus MODIS from the collocated match-ups (g,h) for the periods of February-May, 2013 (left column) and June-August, 2013 (right column). Global VIIRS and MODIS AOT550 are gridded at 1° resolution. Values beyond the range of color bar are represented by the end colors.

February-May, 2013 June-August, 2013

VIIRS

MODIS

VIIRS-MODIS

VIIRS-MODIS Collocated

(Liu et al., JGR, Submitted)

Global Daily Aerosol Observations

Global high quality EDR aerosol optical thickness at 550 nm on May 22, 2013

Condition Pixel Quality Level

Degraded Excluded Not Produced

Out of Spec Range X Coastal or Inland Water X

Cloud Contamination X Cloud Adjacency X

Cirrus X Invalid SDR data X

Sun Glint X Cloud Shadow X

Snow/Ice X Fire X

Soil Dominated X Bright Surface X Turbid Water X

Ephemeral Water X 65° ≤ SolZA < 80° X

SolZA ≥ 80° X Large Retrieval Residual X

(Jackson et al., JGR, In Press)

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Event Monitoring: Wildfire and Heavy Smoke

With AOT retrievals at IP (750m) and EDR (6km) levels, the VIIRS aerosol products monitor global aerosol events with comparable performance to its counterpart from the MODIS heritage.

US wildfire, 4 July 2012

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Event Monitoring: African Dust Storms

The VIIRS AOT EDR captured the African dust storm on July 30, 2013.

RGB

VIIRS AOT EDR High Quality

Data (not SM) are available through NOAA/CLASS: http://www.class.noaa.gov (EDR released from 05/02/2012; IP will be released soon.) The IDEA site that compares MODIS over CONUS: https://www.star.nesdis.noaa.gov/smcd/spb/aq/index_viirs.php?product_id=4 To get gridded data (0.25 degree): http://www.star.nesdis.noaa.gov/smcd/emb/viirs_aerosol/index.php Users’ guide available at: http://www.star.nesdis.noaa.gov/jpss/ATBD.php#S126472 README file under VIIRS aerosol (AOT) at: http://www.nsof.class.noaa.gov/saa/products/welcome Other documents are available at: http://npp.gsfc.nasa.gov/science/documents.html 14

Obtaining VIIRS aerosol data and documentation

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NOAA CLASS: The Primary Gateway for the VIIRS Data Distribution

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IDEA: VIIRS vs. MODIS vs. GASP Aerosol Observations over CONUS

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• The VIIRS aerosol products reached beta maturity on May 2, 2012 and provisional status on Jan 23, 2013.

• The VIIRS Aerosol EDRs provide similar global aerosol distributions showing potential for continuing their heritage satellite products from MODIS.

• With better spatial resolution over a wide spectral range and increased daily spatial coverage, the VIIRS Aerosol EDRs demonstrate great capability and potential for global aerosol event monitoring.

• Filtering the VIIRS Aerosol EDRs with the extensive quality flags available is highly recommended. Best quality assured data usage is preferred. Consult the documentation or the VIIRS Aerosol Cal/Val team.

• The VIIRS aerosol products were evaluated against ground measurements (AERONET, MAN etc.) during the intensive Cal/Val activities, results reported in the following up talk given by Ho-Chun Huang.

Summary

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Backup Slides

VIIRS versus MODIS

Suomi-NPP (13:30 Local Time, Ascending); Aqua (13:30 Local Time, Ascending)

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S-NPP VIIRS Aqua MODIS

Platform Suomi-NPP Aqua

Orbit 824 km 690 km

Equator Crossing 1:30 pm Local Time 1:30 pm Local Time

Repeating Cycle 16 days 16 days

Swath 3200*768 pixels

(85 seconds, ~3000 km)

1354 * 2030

(5 minutes, ~2300 km)

Spectral Range 0.412-12.2µm (22 bands, including 8 dual gain bands) 0.412-14.5µm (36 bands)

Resolution at Nadir 375m (I-band) /750m (17 M-bands) 250m/500m/1km

Resolution at edge 750m 1.5 km 500m 2 km

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Aerosol Algorithm Differences between VIIRS and MODIS

VIIRS Aerosol Products MODIS Aerosol Products Aggregates AFTER retrieval (outputs of IP AOT at 0.75km), discarding outliers

Aggregates BEFORE retrieval (inputs of TOA reflectance to 10km), discarding outliers

Robust AOT at standard 6 km resolution at nadir, 12 km at edge (0.75 km and 1.5km in IP)

Robust AOT at standard 10 km resolution at nadir, 40 km at edge (3km and 12km in C6)

Heavily dependent on external VIIRS Cloud Mask

Mostly dependent on internal cloud mask.

NO negative values. Max AOT = 2.0 YES negative values. Max AOT = 5.0 NO great lakes retrievals yet YES great lakes retrievals YES level 3 gridded products available but not operational

YES Level 3 daily, 8-day, monthly mean

NO bright surface retrievals yet YES Deep Blue aerosol products

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Aerosol Algorithm Differences between VIIRS and MODIS (Continued)

VIIRS Aerosol Products MODIS Aerosol Products LAND bands: 0.41, 0.44, 0.48, 0.67, 2.25 µm

LAND bands: 0.47, 0.66, 2.12 µm

LAND: chooses from five aerosol model LAND: mixes fixed fine and coarse models LAND: fits to atmospherically corrected surface reflectance ratios of 0.41, 0.44, 0.48, 2.25 µm over 0.66 µm

LAND: fits to TOA reflectance (Linear relation between 0.66 and 2.12 µm as a function of NDVI and scattering angle; linear relation between 0.47 and 0.66 µm)

OCEAN bands: 0.67, 0.74, 0.86, 1.24, 1.61, 2.25 µm

OCEAN bands: 0.55, 0.66, 0.86, 1.24, 1.61, 2.12 µm

OCEAN: Dynamic selection of 2020 possible combinations of 4 fine and 5 coarse modes and 101 fine mode fractions

OCEAN: 200 combinations of 4 fine model, 5 coarse mode and 10 fine mode fractions

Land and Ocean Spectral AOT at 11 wavelengths with 1 primary wavelength

LAND AOT at 3 wavelengths, Ocean AOT at 7 wavelength, with 1 primary wavelength