The corresponding daily time series plots of surface weather reports at Beijing Capital International Airport (below) revealed that the surface visibility remained below 1.0 statute miles for extended periods. Although not indicated on the 26 November plot, the surface visibility began at 19 statute miles on that day, before the wind speeds became 4 knots or less beginning at 10 UTC.
On the following day, the fire burn scar could be seen in a comparison of Suomi NPP VIIRS true-color and false-color images from the SSEC RealEarth site (below).Due to the darker color and the lack of vegetation, the grass fire burn scar also exhibited a much warmer signature on the Terra MODIS Land Surface Temperature (LST) product (below) — LST values were as high as 112º F (darker orange color enhancement) within the burn scar, compared to LST values in the 80s and 90s F in surounding areas.
The corresponding GOES-13 infrared (10.7 µm) images (below; click image to play animation) showed that cloud-top IR brightness temperatures were as cold a -53º C (orange color enhancement) at 1915 UTC.The volcanic cloud features were also easily tracked on GOES-13 water vapor (6.5 µm) images (below; click image to play animation). In fact, note how the signature in the water vapor imagery is more distinctly seen for a longer period of time than on the 10.7 µm infrared imagery. The tan-colored volcanic ash cloud was also evident on Aqua MODIS and Suomi NPP VIIRS true-color Red/Green/Blue (RGB) imagery (below), as viewed using the SSEC RealEarth web map server. A comparison of Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images is shown below (courtesy of William Straka, SSEC). The coldest cloud-top IR brightness temperature was -72.7º C.
A more detailed view of the fire hot spots was provided by 375-meter resolution (mapped onto a 1-km AWIPS grid) Suomi NPP VIIRS 3.74 µm shortwave IR images (below; click to play animation).Many of the fires were burning in the general vicinity of the Utopia Creek, Indian Mountain airport (station identifier PAIM); a time series of surface observation from that site (below) showed that visibility was 1 mile or less due to smoke at times on 25 July. Daily composites of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images viewed using the SSEC RealEarth web map server are shown below.