Having lived just outside the imaged area, 8-10 miles due east of JFK (easily spotted as the rectangular 'white' area on the east margin), I believe the 2013 to 2017 change in color of lighting is entirely accurate insofar as ground level conditions and perceptions.
As to 'darker areas' it might be color sensitivity, but I think the second photo is showing more of the illuminated ground itself. You could also look into high albedo snow coverage on the ground at the time of the photos, which varies radically in the New York City area. But, if that were the case, however, the park and cemetery areas in the middle of queens that look kind of like a lake, would probably show up brighter with uncleared snow coverage.
It is entirely possible that less direct sky illumination was present in the newer photo, but that's a partial guess. If entire fixtures were replaced there may have been less direct sky illumination in the second photo.
It is also interesting that some of the more orange area seem to be in the park, parkways and cemetery areas of Queens. Also, wild how unchanged Staten Island was in 2017.
I never recalled reading about the lighting changes in the broader area publications, but I read only 2 of the 4 big ones of the papers.
The Towns (3 large political subdivisions, as opposed to villages, in Nassau County, starting about at the right photo margin) in Nassau seem to have switched over in the same time period, but I was not personally aware of a total replacement effort and believe it was probably old bulb replacement and perhaps a slow swap out and relighting one of more of the handful of the main highways. The Nassau and Suffolk photos would interesting.
From the ground level it was somewhat difficult to notice the change from day to day, but over a two or three year period, not sure which years, light pollution became remarkably worse after being constant for at least a decade in my area just east of the airport in Western Nassau. My pollution and atmospherics were so awful in my area, combined with work schedules, I was only an occasional observer at night. Too frustrating.
From 2006 until I left NY in 2019 I was also frequently flying to Phoenix, landing at night much of the year, where I suddenly became conscious on one trip that nearly all lighting had become blue white over the east and southeast approach areas near the airport, much of which was rapid new construction.
I will have to politely disagree once again on the dynamic range issue on the photos.
While there's no question that sensors (and even properly prepared film, remember hypering?) can perceive the color range better and are more sensitive, we have to remember that that happens with long exposures, certainly not necessarily the case with snapshots taken from the moving ISS.
Film dynamic range was particularly bad. Back in my darkroom hobby days photos had to be extensively dodged and burned to restore a natural effect to what we recall having seen by eye.
Sensors are much better but simple minor changes in exposure can radically change the appearance of a photograph, so dynamic range remains an issue, but I'll limit that to short exposure photographs similar to snapshots.
Which are the kind of photos we normally compare to our memory of a scene by eye.
In these kinds of situations with light pollution, we are normally talking about dark adapted eyes anyway (well, as dark adapted as you can get under Bottle 9+ skies!).
I vaguely recall that the light pollution maps are generated from satellite data, but I still find they fairly accurately map the mid and low ranges of light pollution, and I think dynamic range of snapshot type photos are why the space short exposure 'snapshots' in those area with mid to low levels of light pollution.
If long exposure photographs were taken from space, I would expect the areas with low level light pollution areas to be more accurately displayed, but the high level areas to be massively overexposed, again due to dynamic range or a similar photographic effect.
But, without going to check, I believe the light pollution maps are actually generated from satellite data, at least that was my recollection as I started to write the next paragraph.
On a barely related note, there are light pollution sites that show different maps generated from different satellite data at different times. Unfortunately, I don't recall at the moment which site had selectable imaging and dating (or the satellite data references).
On those maps, one can track that there has been an acceleration of light pollution over the last 5 to 10 years.
On sites that I've regularly consulted over the last 5 years, particularly with reference to locating observation sites in Arizona within an hour of my upcoming home (my elderly parents house), there have been noticeable and significant changes over the last 5 years with a couple of perspective sites going from B2 to B3. Congress, northwest of Wickenberg was one rapidly changed area as I recall.
That was very unexpected over such a short time period. In an accidental interaction with someone living in Congress, 4 months ago, I was told that there had been a recent expansion of construction in that area.
All In all, I find the dark site maps to be reasonably accurate for the mid and low level light pollution zones, matching ground level impressions, with the exception of light dome glow areas.
Edited by markb, 28 February 2022 - 08:43 AM.
