A new consistently processed time series of annual global VIIRS nighttime lights has been produced from monthly cloud-free average radiance grids spanning 2012* to 2020. The new methodology is a modification of the original method based on nightly data (Annual VNL V1).
* For 2012 annual VNL V2, there are two sets. (A) 201204-201212, and (B) 201204-201303. Only set (B) has masked median and average, as well as lit area mask.
In both methods there is an initial filtering to remove sunlit, moonlit and cloudy pixels, leading to rough composites that contains lights, fires, aurora and background. In the original method, the rough annual composites are made from a full year of nightly DNB data. In the new method, the rough composites are made on monthly increments and then combined to form rough annual composites. Both methods employ outlier removal to discard biomass burning pixels and isolate the background.
In the original method the outlier removal is performed on scattergrams generated for each 15 arc second grid cell, with outliers clipped off from both the high and low radiance sides of the scattergram. The discard of outlier pixels proceeds until the scattergram’s standard deviation stabilizes. The new method uses the twelve-month median radiance to discard high and low radiance outliers, filtering out most fires and isolating the background. Background areas are zeroed out in both methods using the data range (DR) calculated from 3x3 grid cells. In both methods, the DR threshold for background is indexed to cloud-cover levels, with higher DR thresholds in areas having low numbers of cloud-free coverages. In the new method, particular attention is given to setting a single DR threshold for distinguishing lit grid cells from background for each 15 arc second grid cell. This is achieved by setting the DR threshold from a multiyear maximum median and a corresponding multiyear percent cloud-cover grids. The multiyear approach makes it possible to detect lighting present in each 15 arc second grid cell with a single DR threshold across all the years in the series.
Elvidge, C.D, Zhizhin, M., Ghosh T., Hsu FC, Taneja J. Annual time series of global VIIRS nighttime lights derived from monthly averages:2012 to 2019. Remote Sensing 2021, 13(5), p.922, doi:10.3390/rs13050922
When using the data please credit the product generation to the Earth Observation Group, Payne Institute for Public Policy, with proper citations as below. Zhizhin, and F.-C. Hsu, “Why VIIRS data are superior to DMSP for mapping nighttime lights,” Asia-Pacific Advanced Network 35, vol. Max Payne was released on October 16, 2008 in Australia, one day prior to the United States release date. Reviews were mostly negative for the lack of character development and originality among numerous differences from the video game on which it is based. Max Payne 3 PC Game Download Free; Action PC Games. 4 years ago 93110 Views. GTA IV Free download PC game full version ISO with direct download links highly.
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|Delivery File Tyle||gz (gzipped)|
|Delivery File Content||average, average-masked, cf_cvg, cvg, max, median, median-masked, min |
|Delivery File Config||vcmslcfg (when available)|
|Image File Type||GeoTIFF|
|Unit||(average, average-masked, max, median, median-masked, min) nW/cm2/sr|
|CRS||EPSG:4326 (Geographic Latitude/Longitude)|
|Resolution||15 arc second (~500m at the Equator)|
|Coverage||180W, 75N, 180E, 65S|