birdseye view

Posted by Ellen

Right around this time last year, Mt. Etna in Sicily started doing this. Again.

Posted by Ellen

The satellite view of Philadelphia in infrared, from a few days ago, led some people to ask for more false-color imagery of our planet. Here we've got a river delta in the tundra of eastern Siberia, where the River Lena empties into the Arctic Ocean. The image is from mid-summer, when the plants of the tundra were bursting with new growth, thanks to twenty-four hours a day of sunlight. The color scheme here is different from that of the Philadelphia scene but still not closely related to the colors a human eye would detect. The data displayed comes from three sensors on the Landsat satellite: one that detects infrared energy, another that detects near-infrared energy, which is very sensitive to the chemicals associated with growing vegetation, and a third sensor that picks up a part of the visible spectrum. Vegetation is green, exposed rock or soil is pink, wet soil (mud) is purple, and ice is blue.

Even in mid-summer, the sea ice floats close to shore. It will take another month or two for most of the ice to melt and/or wash out to sea, but as soon as it does freezing temperatures will return and ice formation will begin again.

The innumerable ponds and distributary streams are typical of flat places throughout the Arctic tundra, where permafrost just below the surface impairs drainage. Meltwater and rainwater sit on top of the permafrost all summer long, breeding mosquitoes...... which don't show up in the satellite imagery.

Posted by Ellen

At about 9:30 in the morning on September 23, 1999, the Landsat 7 satellite swooped southward over eastern North America and captured this image of Philadelphia and environs.

Three of the Landsat sensors detected energy in the infrared part of the electromagnetic spectrum, completely invisible to the human eye. Data from these sensors is displayed here, with each of the three infrared bands assigned to one of the normal red-green-blue color bands so we at least have something to look at, even though the colors have nothing to do with normal vision.

Clicking on the picture brings up a bigger version, which shows much more detail.

We can tell right away that the rivers are black; infrared energy is completely absorbed by water, reflecting back nothing for the sensors to detect. And if we look along the river at lower left, we can make out the airport, with runways that are bright cyan in color. This white-to-bluish hue is also the color of roads, railroads, parking lots, and other paved surfaces.

Infrared data is especially useful for studying vegetation, which shows up in this color scheme as red, orange, or yellow. The brightest red patches represent vigorous herbaceous growth, such as healthy cropland in the midst of the growing season. There's little or no farmland in and around Philly, however, so the red patches we see here, such as in between the airport runways, are probably healthy weeds.

Patches of red coloration with a touch of an orange tint and some texture are forested areas, such as in parks or between the fairways of golf courses. Extremely vigorous grass, such as on the golf course fairways themselves, looks bright yellow in this view.

The brownish-to-grayish-to-bluish areas show mixed land cover: Landsat's sensors are averaging out the infrared signals from house roofs, pavement, lawns, shrubs, and trees in varying concentrations. Brownish areas are suburban, with lots of trees and grass; dark green to gray-blue areas are more urban, with a higher ratio of rooftops and pavement to vegetation.

Philadelphia has changed since this image was captured twelve years ago. Another stadium has been built near where the Schuylkill River empties out into the Delaware. In my neighborhood just south of Center City, the forested patch of land near the Schuylkill, which in 1999 was an abandoned and overgrown Old Sailors' Home is now a heavily developed condo complex. Even though the population of Philadelphia has shrunk dramatically over the past half-century and has just barely started growing again, land use patterns as viewed from outer space show ongoing urbanization.

Posted by Ellen

As the sun sets over New Jersey, the Milano's Italian Sausage trucks begin their nightly rounds in Manhattan.

New York City's new High Line Park repurposes an old elevated railroad track along the west side of lower Manhattan for strolling and people-watching high above the bustle of downtown streets. Trees and flowers grow out of the old track bed, blooming between the ties, while in the distance is the river, the skyscrapers, the restaurants and nightclubs, and, along this stretch of the route, the warehouses of the old meatpacking district.

 

Posted by Ellen

A couple of weeks ago, when the International Space Center was looping around the southern part of the globe, heading toward Antarctica from Australia, astronauts used the little digital camera on board to snap this picture.

The fires were intentionally set by farmers clearing fields or pastures to make way for spring growth. The green horizon is the Aurora Australis, bright pulses of electromagnetic energy released when solar pulses are deflected toward the earth's southern magnetic pole. Green is the most common color of auroras, produced when solar energy disrupts the normal spinning of oxygen molecules in the upper atmosphere; auroras can also be red, pink, or orange, depending on the atmospheric gases involved.

The space station itself is visible across the top of this photo and in the lower right corner.

 

Posted by Ellen

Polish photographer Marcin Sacha has recently added the landscapes of Andalusia, Spain, to the range of scenes in his portfolio.

Posted by Ellen

 


 

(Image removed at the request of the photographer, Cris Benton)


 

This view of Drake's Beach at Point Reyes National Seashore in California is another example of kite photography, one of the oldest applications of the photo arts.

During the American Civil War, kites and balloons were used to hoist cameras, and sometimes also cameramen, for spying expeditions. Kite photography was also used to survey the damage after San Francisco's 1906 earthquake and fire. 

Planes and satellites, of course, have relegated kite photography to niche status. On the other hand, modern digital cameras and wireless control technology have become so lightweight and inexpensive that it's a readily accessible niche.

Posted by Ellen

Way, way out in the country, a million miles away from city lights, on a clear night the sky is lit by stars, as we see above at left, in a photo taken in Glacier National Park in Montana. The few small clouds in this starlit sky show up as black blotches that block some of the stars; a completely cloudy night in remote parts of the world is a very, very dark night, too dark to photograph at all.

In the megalopolis, however, clouds actually light up the sky by reflecting urban light pollution to brighten the night dramatically; an overcast night in a big city like Berlin, shown above at right, can be up to ten times brighter than a clear night.

Posted by Ellen

Kuala Lumpur, Malaysia, from 30,000 feet.

Posted by Ellen

"Lee, Brian & Jeff making dinner," notes photographer Rich Durant, who snapped the picture of the men at their campsite along the Lorillard River in Nunavut. The Lorillard flows across tundra and bare rock of the billion-year-old Canadian Shield to enter Hudson Bay near the latitude of the Arctic Circle.

Where was Rich standing when he took this shot? It doesn't really matter; he had flown the camera up into the sky by hanging it from a kite and was using a remote control mechanism to operate the shutter while remaining safely on the ground.

The men were canoeing down the whitewater of the Lorillard; as you can see, they had stowed their gear in drysacks and waterproof boxes. The sacks and boxes don't look particularly bear-proof, however, and it's not clear what kind of arrangements they might be making to keep their food away from bears and other critters.

Whatever they were doing, it apparently didn't work out too well. The pictorial record of the expedition–called "Lorillard River Briefly"–includes photos (taken from the ground) of wolf tracks and big white bears, and then . . . a tent and foodsack trashed by something big and hungry.