Hot Spots at Ground Zero

During twenty-five flight missions, EarthData personnel used two infrared cameras to capture thermal data that firefighters used to plan their work and assess the effectiveness of different fire-fighting techniques. The first camera recorded data onto VHS tapes, and after each flight EarthData personnel produced black-and-white digital still images showing temperature conditions at the areas of greatest interest: 1 World Trade Center (North Tower), 2 World Trade Center (South Tower), and 7 World Trade Center. After each mission, EarthData personnel used software to create mosaics of multiple thermal images.

The mosaics below were produced on September 16, 2001, when many fires were still burning. The lighter the shade of gray, the higher the temperature.					These mosaics were created on October 21, 2001, after most of the fires had been put out and debris removal had begun.

Seeking to pinpoint the location of fires and hotspots, EarthData imported these mosaics into a Geographic Information System and aligned with corresponding orthophotographs of the World Trade Center site.

The second camera captured black-and-white digital thermal images. After creating large mosaics that combined multiple images, they then imported the mosaics into a Geographic Information System, placed them atop recent orthophotographs of the World Trade Center site, and colorized the temperature values. These overlays helped emergency personnel plan their work and avoid areas that remained dangerously hot.

The overlays below document thermal conditions at the World Trade Center site on October 20, 2001. The first image is of the northernmost section of the site, and the last image is of its southernmost section.

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