1. Overview of Case Studies of VIIRS Aerosol Products for Operational Applications Amy Huff Pennsylvania State University VIIRS Aerosol Science and Operational Users Workshop November 22, 2013

2. S-NPP VIIRS Products on IDEA True color imagery (RGB): – Combination of red, green, and blue bands of VIIRS – 750 m resolution – Looks like a photograph – Useful for identifying areas of smoke, haze, and dust 2 20130909

3. S-NPP VIIRS Products on IDEA Aerosol Optical Thickness (AOT): – Analogous to AOD from MODIS – Unitless measurement; represented on a color-coded scale ranging from 0 to 1 – Related to PM 2.5 in atmosphere – Complements RGB imagery – Clouds block measurement of AOT 3 20130909

4. VIIRS Intermediate Product (IP) AOT 750 m resolution 4 quality flags (see Product Description): High, Degraded, Excluded, Not Produced IP AOT on IDEA Case Study Site: – IP High: cloud-free IP AOT of the highest quality (use for quantitative applications) – IP High*: IP High AOT plus degraded AOT due to cirrus clouds or soil-dominated surfaces (use for qualitative applications – comparable to MODIS Aqua AOD) – IP High & Degraded: IP High AOT plus all degraded AOT (see Table 2 in the Product Description for a list of degraded conditions) 4

5. VIIRS Environmental Data Record (EDR) AOT Aggregated from IP AOT retrievals in a 8 × 8 pixel box 6 km resolution 3 quality flags (see Product Description): High, Medium, Low EDR quality flag based on number of IP AOT pixels with a particular quality flag falling inside or outside a threshold number – e.g., EDR High AOT are comprised of >16 IP pixels (out of a possible 64) and all of the IP pixels are IP High quality EDR AOT on IDEA Case Study Site: – EDR High – EDR High & Medium 5

6. IP/EDR AOT Coverage Comparison Spatial resolution of IP (750 m) vs. EDR (6 km) pixels < 16 IP High AOD pixels available (requirement for EDR High AOT) Lat/Lon used for center of IP AOT pixels and EDR AOT pixels is different 6 IP High (750m) EDR High (6 km)

7. Validation Status of VIIRS AOT Products VIIRS AOT products are provisional: – Product quality may not be optimal Product accuracy is determined for a broader (but still limited) set of conditions No requirement to demonstrate compliance with specifications – Incremental product improvements are still occurring – The general research community is encouraged to participate in the QA and validation of the product, but users need to be aware that product validation and QA are ongoing – Users are urged to consult the EDR product status document prior to use of the data in publications – The data are ready for operational evaluation 7

8. IDEA Case Study Website 8 select date select version of AOT and quality flags change RGB/AOT opacity visualization options download imagery select CONUS or global imagery zoom in/out

9. Case Study Breakout Session http://www.star.nesdis.noaa.gov/smcd/spb/aq/viirs_workshop_2013/ http://www.star.nesdis.noaa.gov/smcd/spb/aq/viirs_workshop_2013/ 2 case studies: July 2 (fires in southeastern Canada) and Sept 9 (Rim fire in California) Step 1: break into groups of 2-3 (need at least 1 laptop) Step 2: review Power Point files of air quality and meteorological conditions for each day Step 3: review operational S-NPP VIIRS AOT and RGB imagery (use Case Study Worksheet) Step 4: answer questions on Case Study Questionnaire about the AOT and RGB products – feedback for NOAA Step 5: group discussion on VIIRS products (after the break) 9