Introduction of the new Suomi-NPP VIIRS Aerosol Products

Transcription

1 Introduction of the new Suomi-NPP VIIRS Aerosol Products Jingfeng Huang 1,2, Ho-Chun Huang 1,2 Istvan Laszlo 2, Shobha Kondragunta 2 Hongqing Liu 2,3, Lorraine Remer 4, Hai Zhang 2,3 1 CICS-MD/ESSIC/UMD 2 NOAA/NESDIS/STAR 3 I. M. Systems Group, Inc. 4 JCET/UMBC

2 VIIRS Aerosol Cal/Val Team Name Organization Major Task Kurt F. Brueske IIS/Raytheon Code testing support within IDPS Ashley N. Griffin PRAIS, 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 2

3 Suomi-NPP satellite launched 28 October 2011 Operational Code Update Date UTC M5.0/5.1 12/09/2011 M5.2 2/1/ :36 M5.3 4/2/ :21 M6.0/6.1/6.2 8/9/ :18 M6.3/6.4 10/15/ :19 Major Event Date UTC NPP Launch 10/28/2012 9:48 First vis/refl. Image 11/21/ :04 First IR/TIR image 1/19/2012 6:20 Rename NPP 1/25/2012 M6.5 11/27/ :58 M6.6 2/28/ :45 M6.7 3/14/ :48 M7.0/7.1 7/10/ :37 M7.2 7/20/ :36 M8.0 11/15/2013 M8.1 1/24/2014 The VIIRS operational algorithm, not only aerosol, keeps evolving over time 3

4 How satellite aerosol retrieval works? TOA Reflectance Aerosol Optical Thickness Surface Reflectance 4

5 Overview of VIIRS Aerosol Data Products 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 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/m 3 ) 0.75 km Type of aerosol (ash, dust, smoke, sea salt, unknown, none) for moderate to heavy aerosol loading, for AOT larger than threshold. 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 5 Evaluation of Suomi-NPP VIIRS Aerosol Optical Thickness, J. Geophys. Res., revision submitted.

6 AOT & APSP Product Timeline Initial instrument check out; Tuning cloud mask parameters Beta status Error Beta status Provisional status 28 Oct May Oct Nov Jan 2013 Red periods: Blue periods: Green period: Product is not available to public, or product should not be used. Product is available to public, but it should be used with caution, known problems, frequent changes. Product is available to public; users are encouraged to evaluate. 6

7 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, 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. 7

8 Seasonal Variability 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 8

9 Monthly AOT Animation 9

10 Global AOT: VIIRS vs. MODIS February-May, 2013 June-August, 2013 VIIRS MODIS VIIRS- MODIS VIIRS- MODIS Collocated 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 matchups (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. (Liu et al., JGR, Submitted) 10

11 Global Daily Aerosol Observations Global high quality EDR aerosol optical thickness at 550 nm on May 22, 2013 Pixel Quality Level Condition Degraded Out of Spec Range Excluded Not Produced Coastal or Inland Water Cloud Contamination Cloud Adjacency Cirrus Invalid SDR data Sun Glint Cloud Shadow Snow/Ice Fire Soil Dominated Bright Surface Turbid Water Ephemeral Water 65 SolZA < 80 SolZA 80 Large Retrieval Residual (Jackson et al., JGR, In Press)

12 Event Monitoring: Wildfire and Heavy Smoke US wildfire, 4 July 2012 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. 12

13 Event Monitoring: African Dust Storms RGB VIIRS AOT EDR High Quality The VIIRS AOT EDR captured the African dust storm on July 30,

14 Obtaining VIIRS aerosol data and documentation Data (not SM) are available through NOAA/CLASS: (EDR released from 05/02/2012; IP will be released soon.) The IDEA site that compares MODIS over CONUS: d=4 To get gridded data (0.25 degree): Users guide available at: README file under VIIRS aerosol (AOT) at: Other documents are available at: 14

15 NOAA CLASS: The Primary Gateway for the VIIRS Data Distribution 15

16 IDEA: VIIRS vs. MODIS vs. GASP Aerosol Observations over CONUS 16

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18 Summary The VIIRS aerosol products reached beta maturity on May 2, 2012 and provisional status on Jan 23, 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. 18

19 Backup Slides 19

20 VIIRS versus MODIS S-NPP VIIRS Platform Suomi-NPP Aqua Orbit 824 km 690 km Aqua MODIS 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 µm (22 bands, including 8 dual gain bands) µm (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 Aqua (13:30 Local Time, Ascending) Suomi-NPP (13:30 Local Time, Ascending); 20

21 Aerosol Algorithm Differences between VIIRS and MODIS VIIRS Aerosol Products MODIS Aerosol Products Aggregates AFTER retrieval Aggregates BEFORE retrieval (inputs of (outputs of IP AOT at 0.75km), TOA reflectance to 10km), discarding discarding outliers outliers Robust AOT at standard 6 km Robust AOT at standard 10 km resolution at nadir, 12 km at edge resolution at nadir, 40 km at edge (3km (0.75 km and 1.5km in IP) and 12km in C6) Heavily dependent on external Mostly dependent on internal cloud VIIRS Cloud Mask 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 YES Level 3 daily, 8-day, monthly mean available but not operational NO bright surface retrievals yet YES Deep Blue aerosol products 21

22 Aerosol Algorithm Differences between VIIRS and MODIS (Continued) VIIRS Aerosol Products LAND bands: 0.41, 0.44, 0.48, 0.67, 2.25 µm LAND: chooses from five aerosol model LAND: fits to atmospherically corrected surface reflectance ratios of 0.41, 0.44, 0.48, 2.25 µm over 0.66 µm OCEAN bands: 0.67, 0.74, 0.86, 1.24, 1.61, 2.25 µm OCEAN: Dynamic selection of 2020 possible combinations of 4 fine and 5 coarse modes and 101 fine mode fractions Land and Ocean Spectral AOT at 11 wavelengths with 1 primary wavelength MODIS Aerosol Products LAND bands: 0.47, 0.66, 2.12 µm LAND: mixes fixed fine and coarse models 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: 0.55, 0.66, 0.86, 1.24, 1.61, 2.12 µm OCEAN: 200 combinations of 4 fine model, 5 coarse mode and 10 fine mode fractions LAND AOT at 3 wavelengths, Ocean AOT at 7 wavelength, with 1 primary wavelength 22