Using the GOES-9 reflectivity product to identify fires (1 MAY 96 CASE)
Kevin J. Schrab, WRH/SSD
The GOES-9 reflectivity product is generated by:
1) Taking the temperature at 10.7um and converting that to an equivalent 3.9um radiance
2) The actual 3.9um radiance is subtracted from the equivalent radiance
3) This leaves a product image that is mostly composed of the reflection of solar radiation
and has a small component due to the emissivity difference between the 11um and 3.9um
channels.
This product can help detect fires and distinguish between water and ice
clouds. It can detect fires since the 3.9um channel has much more sensivity to hot
temperatures than the 10.7um channel. So fires are detected due to the small component
that is due to emissivity differences. For this same reason the fog product detects fires
very well. NOTE: Fires show up as black in the fog/stratus product.
In the examples below, from RAMSDIS, the fire shows up as bright (yellow, with extreme
temperatures) in the reflectivity product. The visible imagery confirms the fire location
as the smoke plume is very apparent.
FIGURE 1a. 1 km VIS imagery (2230Z 1 May 1996) Figure 1b. 3.9um image displayed at 1 km resolution (2230Z 1 May 1996)
FIGURE 2a. 1 km VIS imagery (2245Z 1 May 1996) Figure 3b. 3.9um image displayed at 1 km resolution (2245Z 1 May 1996)
FIGURE 3a. 1 km VIS imagery (2300Z 1 May 1996) Figure 4b. 3.9um image displayed at 1 km resolution (2300Z 1 May 1996)
FIGURE 4a. 1 km VIS imagery (2315Z 1 May 1996) Figure 5b. 3.9um image displayed at 1 km resolution (2315Z 1 May 1996)
FIGURE 5a. 1 km VIS imagery (2330Z 1 May 1996) Figure 6b. 3.9um image displayed at 1 km resolution (2330Z 1 May 1996)
FIGURE 6a. 1 km VIS imagery (2345Z 1 May 1996) Figure 2b. 3.9um image displayed at 1 km resolution (2345Z 1 May 1996)
Please send comments to:Kevin J. Schrab