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Earth Matters

Twelve Years of Fires

July 20th, 2012 by mscott

Besides acquiring photo-like images of the surface of Earth, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites can detect the anomalously high temperatures associated with actively burning fires. Using this “hotspot” data, John Nelson of IDV Solutions made a map of major fires in the contiguous 48 United States from 2001 through early July 2012.

Image courtesy John Nelson, IDV Solutions.

This map shows not just the locations, but also the intensity of major fires. Nelson has scaled the fires by “units of the typical American nuclear power plant’s summertime capacity.” The most intense fires are yellow, and less intense fires appear in shades of magenta and purple. Graphs in the lower left corner show the proportion of fires by year and by month.

Jessica McCarty, who studies U.S. fire patterns at Michigan Tech Research Institute, observes that the most intense blazes are usually wildfires in forested or peatland areas. Prescribed fires to benefit agriculture and ranching are generally less intense.

A high-resolution version of this image is available here.

Answer to July Puzzler: Dudinka, USSR

July 17th, 2012 by Adam Voiland

This image was acquired by a Gambit satellite on July 15, 1966. Click on the image for a larger view.

Congratulations to Yiannis Raftopoulos for being the first to correctly identify that our second satellite puzzler was a view of Dudinka, a port city along the Yenisei River in northern Siberia. Raftopoulos submitted his answer just 15 hours and 51 minutes after we posted the image—not quite as fast as Alexandre Manthieu was at solving our first puzzler, but still quicker than we had expected given that the image came from a declassified GAMBIT spy satellite and was taken 46 years ago this week. We also received insightful comments from Mark H. (who deduced it was the Arctic, based on the shape of the lakes) and from Anthony Williams (who realized it wasn’t the United States due to the existence of a lone soccer field). Thanks to all who participated. We’ll post a complete caption as our Image of the Day on July 20, 2012.  And look for a new puzzler in August.

Help Find an Alphabet in the Sky

July 13th, 2012 by Adam Voiland

NASA image courtesy Jeff Schmaltz, LANCE MODIS Rapid Response. This image was acquired on July 11, 2012, by the Aqua satellite.

One of the first things that caught my eye when I started checking for interesting satellite imagery yesterday was this: an enormous “V” of smoke draped over northern Canada, as seen by the MODIS instrument on the Aqua satellite. The plume was caused by numerous wildfires burning in the Caribou Mountains of northern Alberta.

At first glance, what looks like a decorative swash on the upper left of the V even reminded me of the look of the N we use on the Earth Observatory to indicate the orientation of an image. It made me think the two might in essence share the same typeface. In fact, the bottom point of the capital V of Adobe Jensen Pro (the typeface of our N) is much wider and curvier than the point in the smoke above. (Wired points out it also looks like the letter Z, which is true if you rotate the image clockwise a bit.)

Still, it’s a memorable image. And it made me wonder: how many other letters have satellites captured momentarily gracing Earth’s atmosphere and oceans? This is the first that I’ve noticed, but I have no doubt there are many more to find given the ceaseless mixing and swirling of clouds, smoke, dust, ice, and even phytoplankton that constantly occurs across our planet.

I think it would be fun to compile a gallery of them, so if you’ve seen a letter (or other typographical mark) in a satellite image, please let me know. Just leave a comment on the thread below. Send a link to what you’ve found, and explain what letter or other typographical mark you think you see.

If you’re feeling especially ambitious, mention what typeface it reminds you of as well. I’ll update this post as new letters come in, and perhaps we’ll eventually have the whole alphabet (plus a good collection of numbers and symbols).  Sending non-English characters is ok: just note what the character is and what it’s called.

Wondering where you can look for imagery besides the EO archives?  Here are a few places to try:

1) NASA Visible Earth
2) The Gateway to Astronaut Photography
3) Jet Propulsion Laboratory Photojournal
4) Scientific Visualization Studio Archives
5) MODIS Image Gallery
6) Landsat Imagery Gallery

Please note: Our gallery won’t likely include many of the high-resolution commercial satellite images that you may have seen on Google Earth because we cannot reproduce those images on our website without buying them. Besides, medium-resolution and low-resolution satellite instruments are actually better for observing large features such as clouds and smoke plumes. Here’s a list of some of the high-resolution instruments that we’ll only be using sparingly, if at all.

EO’s Satellite Puzzler: July 2012

July 10th, 2012 by Adam Voiland

Click on the image for a larger view.

Every month, NASA Earth Observatory will offer up a puzzling satellite image here on Earth Matters. The second puzzler is above. Your challenge is to use the comments section below to tell us what part of the world we’re looking at, when the image was acquired, and what’s happening in the scene. Bonus points if you can do it in less than 2 hours and 56 minutes—the amount of time it took Alex Mathieu to successfully solve our first satellite puzzler.

How to answer. Your answer can be a few words or several paragraphs. (Just try to keep it shorter than 300-400 words). You might simply tell us what part of the world an image shows. Or you can dig deeper and explain what satellite and instrument produced the image, what bands were used to create it, and what’s interesting about the geologic history of some obscure speck of color in the far corner of an image. If you think something is interesting or noteworthy about scene, tell us about it.

The prize. We can’t offer prize money for being the first to respond or for digging up the most interesting kernels of information. But, we can promise you credit and glory (well, maybe just credit). Roughly one week after a “mystery image” appears on the blog, we will post an annotated and captioned version as our Image of the Day. In the credits, we’ll acknowledge the person who was first to correctly ID an image. We’ll also recognize people who offer the most interesting tidbits of information. Please include your preferred name or alias with your comment. If you work for an institution that you want us to recognize, please mention that as well.

You can read more about the origins of the satellite puzzler here. Good luck!

A Unique View of Wildfire Smoke

July 9th, 2012 by Adam Voiland

We publish a lot of wildfire imagery on our natural hazards page (particularly after the wildfire season ramped up recently in Colorado and other states in the western U.S.)  Most of the imagery is acquired during the day by instruments on polar-orbiting satellites: the Moderate Resolution Imaging Spectroradiometer (MODIS) on Aqua and Terra, the Advanced Land Imager (ALI) on EO-1, or the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on Terra.

So it caught our eyes when this image of wildfire smoke at night—captured by the Expedition 31 crew on the International Space Station—turned up on Marshall Space Flight Center’s Flickr page. Faint smoke is visible drifting near Ciudad Juaréz, Mexico, and El Paso, Texas — neighboring border cities along the Rio Grande. It isn’t possible to distinguish the U.S./Mexico border, but a line of lights along Interstate 10—which is slightly north of the border—is visible.  (See this story about city lights viewed from space for a clearer view of Interstate 10 and the border). It’s likely the smoke originated from the Whitewater-Baldy wildfire, a large blaze that has been burning 225 miles to the northeast of El Paso in Gila National Forest.

The photo was taken on June 2, 2012, with a Nikon D3S, a digital single-lens reflex camera identical to what’s available to consumers. A Russian spacecraft  docked to the station is visible on the left side of the image.

On June 29, 2012, a long-lived, fast-moving windstorm blew over the eastern United States. The storm started in northwestern Indiana and, over the next 10 hours, traveled roughly 600 miles (1,000 kilometers) toward the East Coast. Wind speeds matched those of an EF-1 tornado in places. The storm uprooted trees, damaged homes, smashed cars, downed power lines, and left more than a million residents of the Washington, D.C. area without electricity.

This photo shows an unusual cloud formation on the leading edge of the June 29 windstorm. Image courtesy Kevin Gould and NOAA.

Meteorologists classified the storm as a derecho—a windstorm associated with fast-moving thunderstorms. A derecho is not a new phenomenon; the term was coined in the late nineteenth century. These storms can rival tornadoes in terms of the damage they cause but, unlike tornadoes, derecho winds generally cause damage in one direction.

The derecho that struck on June 29, 2012, occurred along the boundary of a stable, dry air mass to the north, and a moist, unstable air mass to the south. Areas affected by the southern air mass were suffering a severe heat wave, including record-breaking temperatures in multiple locations. The high heat and humidity provided energy to the strong winds. The thunderstorms sucked up warm, moist air and subsequently returned it in downdrafts. Hitting the ground at tremendous speed, the downdrafts fanned out over the surface, sometimes picking up speed.

The U.S. National Oceanic and Atmospheric Administration (NOAA) provides a primer on derechos, and an overview of the June 29 event. The Capital Weather Gang also provides a summary of the event.