Night-Sensitive Satellite Spots Elusive Clouds
NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership
Marine layer clouds seen off the California coast at night by the Suomi NPP satellite, which can see certain nighttime features that were undetectable by previous satellite methods.
May 15, 2012, Ormond Beach, Florida. Photo by
Oct. 2, 2012 --
NASA's Global Precipitation Measurement satellite mission is working to understanding extreme weather with photos of rain and snow worldwide every three hours. But how do these storms look on the ground? NASA's GPM extreme weather photo contest highlights the beauty and ferocity seen first hand from storm-chasers before they duck for cover. Here are NASA's top five picks from over 100 submissions. This photo by Jason Weingart, a photography student at the University of Central Florida, shows a Volusia County lifeguard signaling to surfers at Ormond Beach, Fla., that it is time to exit the water. "The storm actually pushed back on shore as it moved south, and then became strong enough for tornado warnings on three separate occasions. I saw a large wall cloud, another spectacular shelf cloud, and some very tight rotation in the couple hours I stuck with the storm after I left the beach in Ormond," wrote Weingart. NASA Fun Fact: "A shelf cloud is a type of arcus cloud with a wedge shape. It is a low level, horizontal cloud formation usually associated with the leading edge of thunderstorms. The leading (outer) part of the shelf cloud appears smooth due to rising cloud motions, while the underside often appears jagged and wind-torn."
May 22, 2011 Dane County, Wisconsin. Photo by
Atmospheric scientist Grant Petty of the University of Wisconsin - Madison, was with a photography club on a farm in Dane County when he saw this thunderstorm building several miles to the east. "The storm cell dropped 1-3/4 inch hail near Sun Prairie. Fall streaks barely visible under the right side of the anvil may in fact be the falling hail,” he said.
PHOTOS: Sun Dogs, Halos, and Double Rainbows
July 5, 2011 Maricopa, Arizona. Photo by Megg
“This photo was taken in a wash that runs through my neighborhood in Maricopa, AZ. The wash runs north/south through the neighborhood and the haboob (type of intense dust storm) was rolling in from the east," reported photographer Meggan Wood. "I saw the wall of dust coming and quickly drove to the wash to get a good wide-open view of the height of the dust looming over the houses. I barely had time to get back to my car before it hit and I was engulfed! The darkness was surprising but it only lasted about 10-15 minutes before it thinned out enough to where I could drive back home, only about 2 minutes away. This was the giant haboob that made national news when it rolled through and entirely covered all of Phoenix and some surrounding cities. Maricopa is about a half-hour drive south of the Phoenix Sky Harbor airport."
PHOTOS: After the Dust Settles
September 1, 2012 Arlington, Virginia, lookin
Journalist Brian Allen with the Voice of America was at home in Arlington, Va., when this storm rolled over Washington. "The storm that blew through started off with an incredible amount of lightning and then dumped a significant amount of rain in a short amount of time -- on the other side of the river. DC got drenched and Arlington didn't see a drop,” he reported.
NEWS: Lightning Still Largely a Mystery
May 30, 2012 Kechi, Kansas. Photo by Brian Jo
Writer and photographer Brian Johnson is a also an avid storm-chaser for several Kansas radio stations. “As a large squall line moved through the area. The National Weather Service had warned about a large scale Derecho forming and moving through," he wrote. "This spawned a couple brief severe thunderstorms that dumped hail on rush hour traffic before the main line moved in. As the bigger storm moved into the Wichita area, reports were coming in of 70 mph winds and hail. There is an open farm field roughly two miles from my house that I shot lightning on the previous night. I sat there for about 20 minutes before this large squall line pushed through the clouds. I was hit with a pretty good gust front as it got closer, but as the winds increased, I decided to get to shelter. This photo was one of the last ones I took." Read more about Johnson's storm-chasing adventure here:
NEWS: Photos Catch Monster Storm's Approach: Big Pics
PHOTOS: Twilight: 15 Reasons to Watch
The nighttime viewing capabilities of the Suomi NPP satellite are giving earth scientists new views of the planet's surface once the sun goes down.
An image taken on Sept. 27, 2012, and released recently by NASA's Earth Observatory, shows off the satellite's penetrating gaze with a view of low-level, marine layer clouds off the coast of California. These clouds are invisible to technologies previously used to view nighttime scenes.
Suomi NPP, run jointly by NASA and the National Oceanic and Atmospheric Administration, took the image with its Visible Infrared Imaging Radiometer Suite (VIIRS) "day-night band," which detects wavelengths of light from green to near-infrared. This means the satellite can spot gas flares, auroras, wildfires, city lights and reflected moonlight, according to the Earth Observatory. And add to that, low-lying clouds.
In the Suomi image, the marine layer clouds shroud the ocean along the California coast, from San Francisco to Los Angeles. You can also see the shadow of some higher-level clouds cast by moonlight onto the low clouds. Marine layer clouds are so called because they form in a sheet over the ocean as low stratus clouds. (Album: Reading the Clouds)
Here's how it works: Winds push moist surface-level air upward, causing it to expand and cool, while at the same time a coastal California feature called the Pacific High causes higher-level air to sink towards the surface, where it warms; these opposing forces create what is called an inversion layer between the surface and upper-air masses, according to the Scripps Institution of Oceanography.
While temperatures in the atmosphere typically get cooler the further up you go, the opposite happens in the inversion layer: Air is cooler toward the bottom, where the surface air is rising, and warmer toward the top of the layer, where the upper-level air is sinking.
If the air rising from the surface cools to a point at which the moisture in it condenses out below the inversion layer, marine layer clouds are formed, bounded on the top by the bottom of the inversion layer. This explains the typically uniform height of the cloud tops. The clouds are bounded on the bottom by the point at which they reach saturation and water condenses out.
These clouds can pose a hazard to ship and air travel, according to the Earth Observatory, but detecting them has been tricky in the past because of the limits of other Earth-observing satellites. Another image of the same scene taken in thermal infrared wavelengths — the band of the light spectrum typically used by meteorologists to observe Earth's surface at night — illustrates this.
This image shows a layer of high clouds seen at night in the thermal infrared specturm of light. A lower level of marine layer clouds sitting below is invsible in this band of light because their temperature is too close to the ground to distinguish them.NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership
In this image, you can only see the higher-level clouds that were casting shadows in the previous image. The marine layer clouds are too close in temperature to the ground to show up as distinct feature in these wavelengths.
Suomi's capabilities therefore give meteorologists another tool to better observe and predict Earth's weather.
More from OurAmazingPlanet:
Image Gallery: Crazy Cloud Patterns
Infographic: Earth's Atmosphere Top to Bottom
In Images: Mysterious Night-Shining Clouds
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