Regional And Mesoscale Meteorology Team
Daily Satellite Discussion
Thursday December 4, 1997
Figure 1 shows the visible image. A clear region over northeast Colorado and most of western and central Nebraska can be seen. This region is bounded on sides of the image by a "white region".
Figure 2 is a display of channel 2. The clear region pointed out above shows up as a light shade of grey. The white region shows considerable structure in this image. The darker shade of grey over western and northwestern Kansas is uniform over this region and depicts the snow covered ground. The uniformaty of the color may only indicate that the snow is deep enough to cover the vegetation and is new. This same shade of grey can be found over southeast Colorado and along the Front Range of Colorado.
An almost black region was over southeast Colorado, southwest Kansas, and over the panhandles of Texas and Oklahoma. This depicts the cirrus clouds composed of ice water. The white region over most of Oklahoma, eastern Kansas, and eastern Nebraska were liquid water clouds (low clouds).
Figure 3 shows the 10.7 micrometer longwave infrared channel. The color table has been shifted towards the warmer temperatures to enhance the ice water cloud deck over southeastern Colorado. Recall these are the same clouds that appeared black in Figure 2. There was also an ice cloud cirrus deck over northern Missouri and most of Iowa. Compare this region to both Figures 2, and 1.
As the past few satellite discussions on snow detection have shown, multichannel analysis is necessary in this endeavor. All past discussions have shown that the visible image by itself is of no use in discriminating between snow, liquid water, and ice water clouds.