Red Sun Over the Netherlands
November 01, 2017
Shown above is a sequence of the morning Sun as it appeared two weeks ago over the Netherlands. Its red-orange coloring was attributed to airborne Saharan dust and to a much lesser degree to smoke from wildfires in Portugal. The dimensions of the fine dust particles (less than about 0.003 mm in diameter) were of the right size to effectively scatter out the shorter wavelength colors. Thus, instead of the solar disk's normal yellow color, it looked as though it might at sunset or sunrise.
Atmospheric patterns associated with the approach of Tropical Storm Ophelia significantly increased the southwestern flow, ushering in the dust and also resulting in several maximum, daily temperature records in northwestern Europe. In addition, a temperature inversion discouraged atmospheric mixing, so the Sun's noteworthy appearance persisted for a number of hours. Photo taken on October 17, 2017.