Potential application of VIIRS Day/Night Band for monitoring nighttime surface PM 2.5 air quality from space

Abstract

h i g h l i g h t sVIIRS Day/Night Band (DNB) is much more sensitive to aerosols than to water vapor Modeling of outdoor light transfer in nighttime atmosphere for VIIRS DNB DNB potential for estimating surface PM 2.5 is shown qualitatively and quantitatively PM 2.5 at VIIRS night overpass time is much closer to daily-mean PM 2.5 than at daytime Strategies for future DNB remote sensing of aerosols are elaborated a r t i c l e i n f o A pilot study is conducted to illustrate the potential of using radiance data collected by the Day/Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polarorbiting Partnership (S-NPP) satellite for particulate matter (PM) air quality monitoring at night. The study focuses on the moonless and cloudless nights in Atlanta, Georgia during AugusteOctober 2012. We show with radiative transfer calculations that DNB at night is sensitive to the change of aerosols and much less sensitive to the change of water vapor in the atmosphere illuminated by common outdoor light bulbs at the surface. We further show both qualitatively that the contrast of DNB images can indicate the change of air quality at the urban scale, and quantitatively that change of light intensity during the night (as characterized by VIIRS DNB) reflects the change of surface PM 2.5 . Compared to four meteorological variables (u and v components of surface wind speed, surface pressure, and columnar water vapor amount) that can be obtained from surface measurements, the DNB light intensity is the only variable that shows either the largest or second largest correlation with surface PM 2.5 measured at 5 different sites. A simple multivariate regression model with consideration of the change of DNB light intensity can yield improved estimate of surface PM 2.5 as compared to the model with consideration of meteorological variables only. Cross validation of this DNB-based regression model shows that the estimated surface PM 2.5 concentration has nearly no bias and a linear correlation coefficient (R) of 0.67 with respect to the corresponding hourly observed surface PM 2.5 concentration. Furthermore, groundbased observations support that surface PM 2.5 concentration at the VIIRS night overpass (~1:00 am local) time is representative of daily-mean PM 2.5 air quality (R ¼ 0.82 and mean bias of À0.1 mg m À3 ).While the potential appears promising, mapping surface PM 2.5 from space with visible light at night still face various challenges and the strategies to address some of these challenges are elaborated for future studies.

Tropospheric emissions: Monitoring of pollution (TEMPO)

“…Recently, the 430 À 480 nm spectral region, where H 2 O is a weak absorber, has been used to retrieve water vapor slant columns from GOME-2 and OMI spectra [115]; H. [116,120]. Water vapor retrieved from the visible spectrum has good sensitivity to the planetary boundary layer, since the absorption is optically thin, and is available over both the land and ocean.…”

Using VIIRS Day/Night Band to Measure Electricity Supply Reliability: Preliminary Results from Maharashtra, India

“…These factors include: (1) geolocation uncertainty of VIIRS DNB, which may range from 249 m (nadir) to 1141 m (edge of swath) [24]; (2) uncertainty in DNB radiometric error (8.9%) [24]; (3) atmospheric effects, such as scattering loss from aerosols, and other sources of airglow [25]; and (4) undetected thin cirrus and other clouds. This may be particularly true in dense urban areas where smaller scale outages may be masked by saturation of the sensor and/or air glow.…”

Inversion of Nighttime PM2.5 Mass Concentration in Beijing Based on the VIIRS Day-Night Band

“…We assume that the upward visible radiation from the earth's surface layer is Lambertian [12]. At night, the satellite crosses Beijing at 1:30 am (local time); as after midnight, the intensity and distribution of city lighting are relatively stable.…”

“…But the radiances from city lamps are primarily greater than 0.4 µm and less than 0.65 µm within the. The city light radiation intensity indicates the variation of PM 2.5 mass concentration well [12].…”