United States Department of Agriculture Forest Service 
Introduction:
Weather Pattern Alert: 
AVHRR Images 2002: 
Archived Images:
Other Images:
Situation Reports: 
Satellite Links:
Weather Links: 
Climate Links: 
Wildfire Maps, News, and Other Links:
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Image Archives
Introduction
This page contains Advanced Very High Resolution Radiometer (AVHRR) Satellite images of the Western United States for past years.
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Disclaimer: Many of the fires shown on this web page have been named using the descriptions of the fires from the daily interagency fire situation reports. Care has been taken to use remote sensing satellites to correctly locate and identify the fires, For a listing of the current fire status and location of fires, see the interagency fire situation report. The USDA Forest Service uses the most current and complete data available. GIS data and product accuracy may vary. Using GIS products for purposes other than those for which they were intended may yield inaccurate or misleading results. The USDA Forest Service reserves the right to correct, update, modify or replace GIS products without notification.
How the images are displayed:
| The AVHRR satellite
bands used for viewing images consist of bands 1, 2, 3 and occasionally
4. Since these bands are located in different parts of the spectrum, they
are used for different purposes. A brief description is given below: |
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The AVHRR satellite bands used for creating the simulated natural color
images are bands 1, 2 and 3. To create the RGB (red, green, blue) image,
band 3 (the thermal infra-red band) is displayed in red, band 2 (the near
infrared band) is displayed in green, and band 1 (visible red) is displayed
in blue. (To see full image, go to
July 3, 2001 7:24 a.m.
)
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Band 1 is in the visible (red) part of the spectrum and is shown in gray
tones. This band is useful in looking at weather patterns and for viewing
smoke. Fires cannot be seen using band 1, but sometimes the smoke they produce
can show up of the image. To see fires, a thermal band must be used. Since
band 1 is a visible band, it can only be used during the daylight hours.
Images during the night are dark and nothing can be seen on the image.
See the example daytime image to the right. (To see full image, go
to July 5, 2000 8:13 p.m.
)
Occasionally band 4 is used if band 1 is unavailable. Band 4 is a thermal band and is not in the visible part of the spectrum. It is sensitive to temperature differences between the land surface and clouds and so by enchancing it the weather patterns can be shown. Images using Band 4 have been enhanced such that they appear nearly the same as band 1. |
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| Band 3 is in the infra red part of the spectrum and is used to pick up the thermal signatures of fires. For display, this band is shown in red tones which enhance the ability to locate fires. Hot objects such as fires will show up as white and cool areas will be very dark. Since this band is a thermal band, it can be viewed during both the day and night. Band 3 is most effectively viewed during the evening hours, and throughout the night into the early morning. Due to the heating of the earth by the sun, band 3 tends to get saturated during the day and fires are hard to locate, if they can be located. See the sample image to the right. (To see full image, go to July 5, 2000 8:13 p.m. ) | 
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Navigating to view the images:
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Images for each year have been grouped by month. To look at the images,
click on the appropriate month under the appropriate year. Images for each
month have their own web page. Each Page has the following Characteristics:
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United States
Department of Agriculture
Forest Service
