Every month we offer a puzzling satellite image here on Earth Matters. The February 2014 puzzler is above. Your challenge is to use the comments section to tell us what the image shows, what part of the world we are looking at, when the image was acquired, and why the scene is interesting.
How to answer. Your answer can be a few words or several paragraphs. (Try to keep it shorter than 200 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 spectral bands were used to create it, or what is compelling about some obscure speck in the far corner of an image. If you think something is interesting or noteworthy, tell us about it.
The prize. We can’t offer prize money, but, we can promise you credit and glory (well, maybe just credit). Roughly one week after a puzzler image appears on this 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 the 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 or attend an institution that you want us to recognize, please mention that as well.
Recent winners. If you’ve won the puzzler in the last few months or work in geospatial imaging, please sit on your hands for at least a few days to give others a chance to play.
Releasing Comments. Savvy readers have solved many of our puzzlers after only a few minutes or hours. To give more people a chance to play, we may wait between 24-48 hours before posting the answers we receive in the comment thread.
However, this joint NASA/JAXA mission is bigger than just one satellite. The scientists behind GPM are hoping that the core observatory will function like a key that “unlocks” and unifies data collected by a whole constellation of existing and future satellites.
For instance, an earlier precipitation-monitoring satellite called the Tropical Rainfall Measuring Mission (TRMM) also used radar to measure precipitation, but it could only detect moderate and heavy rain in tropical areas. GPM, in contrast, will also sense light rain and snow and will see nearly to the poles (65 degrees latitude north and south), meaning it will extend and improve upon TRMM’s measurements.
Expect to hear a lot more about this satellite over the next few weeks. There’s a lot of information to sift through if you want to learn more about the mission, but some of it can be tricky to find. To make the sifting a little easier, I’ve compiled a “best of guide” to images and other resources about the mission to make your search a little easier. Stay tuned for more, follow the mission via @NASA_Rain and on Facebook, and enjoy the launch.
It’s funny what you can find in a satellite image. Mike Gartley, a research scientist at Rochester Institute of Technology, spotted the Landsat 5 satellite lurking in a Landsat 8 image of northwestern Brazil.
Landsat 5 is just a few blurry pixels in Landsat 8’s panchromatic band.
Landsat 5 once flew in the orbit that Landsat 8 now lives in. But in January 2013, the U.S. Geological Survey lowered L5’s orbit about 23 kilometers (14 miles) as part of the decommissioning process. The satellite is now in a disposal orbit, slowly being dragged back to Earth.
Landsat 8, meanwhile, reached its final orbiting altitude of 705 kilometers (438 miles) on April 12, 2013. On November 22, Landsat 8 flew over the defunct Landsat 5 satellite, capturing this view of its predecessor. Landsat 5 is just a few pixels across and is only visible at all because it is much closer to Landsat 8 than it is to Earth. See additional images from the November 22 overflight on NASA’s Landsat web site.
Finding Landsat 5 in the image was a matter of course for Gartley, who routinely hunts for space objects in Landsat images. As of December 2011, more than 22,000 “resident space objects” were in orbit around the Earth. The Space Surveillance Network tracks all of these objects with telescopes, radars, and a computer model. Gartley uses this information to figure out when an object will fly into Landsat 8’s view.
“Believe it or not, there are anywhere from 1 to 4 such underflights of space objects that are passing through the field of view of Landsat 8 on any given day,” says Gartley. “Many of the objects are old rocket bodies and COSMOS satellites (Tselina-D ELINT type), while the ISS has also popped up at least three times since last May.”
The International Space Station seen from Landsat 8.
Landsat 5’s appearance is appropriate: it’s the satellite that just won’t go away. The tenacious satellite was built to operate for 3 years, but worked for more than 29, setting a world record for the longest operating Earth observation satellite. Even the decommissioning process took longer than expected because the satellite kept running. Hear the story from longtime flight systems manager for Landsat 5, Steve Covington, in this recorded talk originally given at the Library of Congress:
Last week we shared an image of an 800-kilometer long bloom of marine protists off the coast of Brazil. In satellite imagery, the bloom appeared navy to black in color, even though the species—Myrionecta rubra—appears red when viewed close-up. The blooms tend to occur just below the water surface, so much red light that the protists reflect gets absorbed before it returns to the satellite. Here’s a look at the January bloom from a boat in the South Atlantic.
The photos were taken in the late afternoon on January 22, 2014. The boat was positioned at roughly 24° 08′ South and 45° 07′ West. The water temperature was 29°Celsius (84°Fahrenheit) and the depth was 70 meters (230 feet).
Thanks to Julio Cardoso, a boater and amateur scientist from Brazil who shared the photos with us. Thanks are due as well to Dr. Aurea Maria Ciotti of the Universidade de São Paulo, who helped us identify the species and the nature of the bloom.
As of February 5, 2014, the bloom appeared to be subsiding, though clouds and haze made it difficult to see clearly from satellites. You can continue to monitor the area by clicking here.
Halos have a long and rich history in religious art, usually symbolizing the presence of someone or something divine. In the physical sciences, the beautiful displays of light are a sign of something more ordinary—the presence of hexagonal, plate-shaped ice crystals that make up cirrus clouds. As gravity pulls the ice crystals downward, their faces become horizontal with the ground and they function as dispersive prisms, breaking sunlight into separate colors and leaving rainbow-like ice crystal halos in the sky.
Sundogs are one of the most common types of ice halo. They occur when light rays enter the side of an ice crystal and leave through another side inclined about 60 degrees to the first. (See Atmospheric Optics for a good diagram that illustrates the process.) Sundogs are most easily seen when the Sun is low in the sky; the halos occurring on either side of it at about 22 degrees. The part of a sundog closest to the Sun always forms a layer of red, while greens and blues form beyond that. Sundogs are visible all over the world and at any time of year, regardless of the temperature at the surface. For more imagery of sundogs and other optical phenomena (such as sun pillars, circumhorizonatal arcs, and parhelic circles), it’s worth checking out the archives of Earth Science Picture of the Day.
In the last few weeks, we’ve had a number of readers send us their photographs of sundogs. The image above was taken by Nina Garcia Jones; the image below comes from Isa DeSil. Thanks for sending the photos our way. To the rest of our readers: keep your interesting photos of atmospheric, meteorological, or geological phenomena coming. We’ll occasionally post the best images on this blog, and we’ll do what we can to help explain the science behind them.