The monster in moonlight: striking satellite image shows Irma churning north in the dead of night

By Tom Yulsman | September 12, 2017 12:01 pm
Suomi NPP Day/Night Band Image over the southeast United States showing Hurricane Irma over Florida, 0710 UTC on 11 September 2017 (Click to enlarge) Source: Cooperative Institute for Meteorological Satellite Studies)

The Suomi NPP satellite captured this photo of Hurricane Irma over Florida at 3:10 a.m. EDT on Sept. 11, 2017. (Click to enlarge. Source: Cooperative Institute for Meteorological Satellite Studies)

As Hurricane Irma continued to churn north over Florida early in the morning of Sept. 11, the Suomi NPP spacecraft passed overhead and sent back this dramatic image.

In the image, acquired by a nighttime sensor called the “Day/Night Band” on the satellite’s VIIRS instrument, the hurricane is illuminated by the relatively faint light of the moon.

But the image reveals more than that. “In addition to the cloud structures, this band can help identify power outages,” writes Scott Lindstrom in the satellite blog of the Cooperative Institute for Meteorological Satellite Studies. “Tampa and Miami city lights are still visible. Key West is dark.”


Part of the Florida Keys at 3:10 a.m. on Sept. 11, 2017. (Source: CIMSS Satellite Blog)

This is a zoomed-in view of the same image. It stretches from Key West toward the lower left to Marathon Key in the upper right corner. Irma’s ferocious winds had knocked out power to most of The Keys. And in this image, there is indeed little to no illumination coming from lights on the ground.

The VIIRS Day/Night Band is designed to capture very low emissions of light. In addition to city lights, it can spot a wide variety of features, including lightning, lava flows, navigation lights from fishing boats, flares from gas drilling operations, and the aurora borealis. And when the moon is up, lunar light can be seen reflecting off ice, snow, and clouds.

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ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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