1. Prospects for Improved Global Mapping of Development Using VIIRS Data Chris Elvidge Earth Observation Group NOAA-NESDIS National Geophysical Data Center 325 Broadway, Boulder, Colorado 80305 USA Tel. 1-303-497-6121 Email: chris.elvidge@noaa.govchris.elvidge@noaa.gov Kimberly Baugh Cooperative Institute for Research in Environmental Sciences University of Colorado, Boulder, Colorado USA June 10, 2012

2. Cities Industrial Sites Boats Gas FlaresFires Lights At Night!

3. Artificial lighting is a excellent remote sensing observable!

4. Two Satellite Systems Collect Low Light Imaging Data at Nights U.S. Air Force Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). 1972 to present. U.S. Air Force Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). 1972 to present. NASA-NOAA Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS). Launched October 28, 2011. NASA-NOAA Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS). Launched October 28, 2011. In both cases the purpose of the low light imaging is the detection of moonlit clouds

5. Comparing DMSP and VIIRS DMSP U.S. Air Force U.S. Air Force Polar orbiting Polar orbiting 07:30 and 19:30 overpasses 07:30 and 19:30 overpasses 3000 km swath 3000 km swath Two spectral bands (vis and TIR) Two spectral bands (vis and TIR) Panchromatic low light imaging Panchromatic low light imaging 2.7 km ground sample distance 2.7 km ground sample distance 5 km+ ground instantaneous field of view 5 km+ ground instantaneous field of view 6 bit quantization (vis) 6 bit quantization (vis) No inflight calibration No inflight calibration Saturation on bright lights in operational collections Saturation on bright lights in operational collections Direct broadcast encrypted Direct broadcast encrypted Archive at NGDC Archive at NGDC Flown since 1972 Flown since 1972 May continue another three years? May continue another three years? VIIRS NASA-NOAA Joint Polar Satellite System (JPSS) NASA-NOAA Joint Polar Satellite System (JPSS) Polar orbiting Polar orbiting 01:30 and 13:30 overpasses 01:30 and 13:30 overpasses 3000 km swath 3000 km swath 22 spectral bands 22 spectral bands DNB panchromatic low light imaging DNB panchromatic low light imaging 742 meter GSD 742 meter GSD 750 meter GIFOV 750 meter GIFOV 14 bit quantization in DNB 14 bit quantization in DNB In flight calibration In flight calibration No saturation No saturation Direct broadcast not encrypted Direct broadcast not encrypted Archives at NCDC and NGDC Archives at NCDC and NGDC Launched in 2011 Launched in 2011 Series expected to continue for several decades Series expected to continue for several decades

6. DMSP Nighttime Visible May 21, 2012 at ~19:30 local time

7. NGDC has produced a time series of DMSP annual cloud-free nighttime lights composites (1992-2011)

8. Coarse spatial resolution of the OLS 2.7 km GSD 5+ km GIFOV OLS lights are larger than sources on the ground “Overglow” surrounds bright sources No visible band calibration 6 bit quantization Urban centers saturate in operational data No 3-5 um band for fires Shortcomings of DMSP Nighttime Lights Contrast enhanced to show dim lighting

9. VIIRS - Visible Infrared Imaging Radiometer Suite

11. VIIRS Nighttime Day / Night Band (DNB) May 21, 2012 at ~ 01:30 local time

12. VIIRS versus DMSP May 21, 2012 VIIRS OLS

13. Detection of Villages in VIIRS Nighttime Visible (DNB) May 21, 2012 at ~ 01:30 local time VIIRS OLS

14. Aerosol daytime only Clouds day and night Fires day and night What Else VIIRS Has To Offer Fire detections - discriminate lights from combustion sources. Cloud optical thickness and snow cover to rate the quality of light detections. Snow Cover

15. What needs to be developed Light detection algorithm Light detection algorithm Terrain correction – DNB data are not terrain corrected since the primary mission is detection of moonlit clouds. Terrain correction – DNB data are not terrain corrected since the primary mission is detection of moonlit clouds. Atmospheric correction – to estimate upwelling radiances at the earth surface. Atmospheric correction – to estimate upwelling radiances at the earth surface.

16. The Way Forward Reuse portions of NGDC algorithm base for processing DMSP nighttime lights: Reuse portions of NGDC algorithm base for processing DMSP nighttime lights: Terrain correctionTerrain correction Light detectionLight detection Cloud-free compositingCloud-free compositing MODTRAN atmospheric correction MODTRAN atmospheric correction

17. VIIRS Stray Light The DMSP light detection algorithm operates with overlapping square tiles to define detection thresholds and assumes that the majority of tile pixels are background. The square tile approach does not appear to be appropriate for VIIRS due to stray light problem.

18. Light Detection Rather than square tiles – it may be more appropriate to analyze individual scanlines – defining a background and noise level that varies from left to right.

19. NGDC’s plan for a 2012 global map of development Initial product will be a mosaic made with a relatively low number of repeat observation. October 2012. Initial product will be a mosaic made with a relatively low number of repeat observation. October 2012. Subsequently a full year product will be processed to characterize the variability in lighting. March 2013. Subsequently a full year product will be processed to characterize the variability in lighting. March 2013. Participate in GEO SB-04 collaborations. Participate in GEO SB-04 collaborations.