TY  - JOUR
A1  - Coesfeld, Jacqueline
A1  - Kuester, Theres
A1  - Kuechly, Helga U.
A1  - Kyba, Christopher C. M.
T1  - Reducing variability and removing natural light from nighttime satellite imagery: A case study using the VIIRS DNB
JF  - Sensors
N2  - Temporal variation of natural light sources such as airglow limits the ability of night light sensors to detect changes in small sources of artificial light (such as villages). This study presents a method for correcting for this effect globally, using the satellite radiance detected from regions without artificial light emissions. We developed a routine to define an approximate grid of locations worldwide that do not have regular light emission. We apply this method with a 5 degree equally spaced global grid (total of 2016 individual locations), using data from the Visible Infrared Imaging Radiometer Suite (VIIRS) Day-Night Band (DNB). This code could easily be adapted for other future global sensors. The correction reduces the standard deviation of data in the Earth Observation Group monthly DNB composites by almost a factor of two. The code and datasets presented here are available under an open license by GFZ Data Services, and are implemented in the Radiance Light Trends web application.
KW  - airglow
KW  - artificial light
KW  - calibration
KW  - VIIRS DNB
KW  - nightlights
KW  - remote sensing
Y1  - 2020
VL  - 20
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Coesfeld, Jacqueline
A1  - Anderson, Sharolyn J.
A1  - Baugh, Kimberly
A1  - Elvidge, Christopher D.
A1  - Schernthanner, Harald
A1  - Kyba, Christopher C. M.
T1  - Variation of Individual Location Radiance in VIIRS DNB Monthly Composite Images
JF  - Remote sensing
N2  - With the growing size and use of night light time series from the Visible Infrared Imaging Radiometer Suite Day/Night Band (DNB), it is important to understand the stability of the dataset. All satellites observe differences in pixel values during repeat observations. In the case of night light data, these changes can be due to both environmental effects and changes in light emission. Here we examine the stability of individual locations of particular large scale light sources (e.g., airports and prisons) in the monthly composites of DNB data from April 2012 to September 2017. The radiances for individual pixels of most large light emitters are approximately normally distributed, with a standard deviation of typically 15-20% of the mean. Greenhouses and flares, however, are not stable sources. We observe geospatial autocorrelation in the monthly variations for nearby sites, while the correlation for sites separated by large distances is small. This suggests that local factors contribute most to the variation in the pixel radiances and furthermore that averaging radiances over large areas will reduce the total variation. A better understanding of the causes of temporal variation would improve the sensitivity of DNB to lighting changes.
KW  - artificial light at night
KW  - light pollution
KW  - night lights
KW  - VIIRS DNB
Y1  - 2018
U6  - https://doi.org/10.3390/rs10121964
SN  - 2072-4292
VL  - 10
IS  - 12
PB  - MDPI
CY  - Basel
ER  -