NASA: Animation of Tsunami Debris

Another visualization from the wizards at NASA, this time illustrating the likely drift of the debris unloosed by Japan's 2011 tsunami. (via Julia Whitty's Blue Marble blog)

NASA's Earth Observatory captions:

This animation shows the output of the Surface Currents from Diagnostic (SCUD) model, an attempt to simulate where and how that debris would disperse. Orange and red shaded areas represent parcels of water with a high probably of containing floating debris. The deeper the red color, the higher the likely concentration. The debris field stretches roughly 5,000 kilometers by 2,000 kilometers across the North Pacific.

To Clarify: Of the Less Erroneous Pictures of Gyres

In news stories about the bath toys lost at sea, or about the so-called garbage patch, one occasionally encounters some confusion about oceanic gyres--altogether understandable confusion because the ocean is a strange place and its currents are complicated, chaotic even. The general as opposed to oceanographic sense of "gyre" is the sense in which Yeats famously used it in "The Second Coming"--

Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold...

--a circular or spiraling motion or form. The oceanographic sense of the word "gyre" is narrower. In oceanography, a gyre is a circuit of major currents. Or to be a bit eye-crossingly precise about it, you'd say a gyre is a circuit of major wind-driven surface currents that orbit the ocean basins. The Gulf Stream, for instance, is a major surface current and it describes one arc of a gyre--the North Atlantic Subtropical Gyre, which, simplified by cartographers at NASA, looks like this:

A gyre is not a "garbage patch." Nor is a gyre by definition a current that collects floating debris. That said, there are currents in the five largest gyres--the subtropical gyres, which include the North Atlantic one pictured above--that do have the tendency to collect floating debris. Such currents create what oceanographers call "convergence zones." Convergence zones lie within gyres, but they are not the same thing as gyres. The most famous one is--take a breath--the North Pacific Subtropical Convergence Zone. You can see why people tend to prefer the somewhat misleading yet far catchier term "garbage patch." Here, on the map that appears at the front of Moby-Duck, is the North Pacific Subtropical Convergence Zone:

The Best Beachcombing in Manhattan

There is one decent beachcombing spot in Manhattan, if you like your flotsam local: a 100-foot-long wedge of sand beneath the Brooklyn Bridge. You can only walk the beach if you’re willing to trespass, squeezing through a narrow opening in the balustrade. It’s not the sort of beach most people dream about. You wouldn’t want to sunbathe there, or walk barefoot. But I like it. It’s one of those accidental places that make the city feel a little wild.

A dozen years ago, I gather, this beach didn’t exist, making it the perfect beach for New York, capital of change and chance. It came into being when tides began depositing sediment behind a little pier built not long ago as a kind of scenic underlook, a good place to take snapshots guaranteed to resemble postcards, the great bridge looming in the background. At the northern end of the beach are the remains of a derelict pier, concrete posts topped by tentacles of twisted rebar. The sand at the southern end of the beach is silty. At the northern end it’s gravelly. A trellis supporting FDR Drive rises out of the gravel, and on the steel of the trellis some latter-day Hart Crane has spray-painted a couplet: 

DN UNDER THE BRIDGE

BIG CITY OF DREAMS.