Thursday, August 26, 2010

Oceanic Garbage Patches may number five

Researchers who have deployed thousands of drifting buoys in the oceans are predicting that every major ocean has a vast debris field, like the Pacific's “Great Garbage Patch.”

This massive region of the Pacific is filled with the refuse of humanity, much of it plastic. Bottle caps, toothbrushes, fishing nets, cigarette lighters, and uncountable shards, slabs and specks of unidentifiable plastic, colored blue and red, white and yellow, brown and black, green and aqua. It is a toxic rainbow hat threatens marine life in many ways.

Nikolai Maximenko, an oceanographer and senior researcher with the University of Hawai'i's International Pacific Research Center, is co-author of a report in Science on a vast study by researchers from the Sea Education Association, Woods Hole Oceanographic Institution and University of Hawaii at Mānoa.

That team, working with plankton nets deployed from a sailboat, located the Atlantic's version of the Garbage Patch—a patch that is predicted by Maximenko's computer model of how converging currents cause oceanic trash to collect in specific regions.

“The study is so exciting because it validates the computer model we’ve developed using more than 15,000 trajectories of drifting buoys,” Maximenko said.

“The purpose of the model is to track long-living objects that float on the ocean surface. Our model has already successfully reproduced the location of the ‘Great Pacific Garbage Patch.’ That now the debris in the North Atlantic collects mostly where our model predicts is further evidence that plastic moves in a similar way that drifters do. We can now expect that our model will be very useful in coordinating debris detection and clean up operations.”

The cool thing about the model is that it explains where the debris can be found, but also why it ends up there, said Sea Education Association researcher Kara Lavender Law, the lead author of the Science paper.

"Not only does this important data set provide the first rigorous scientific estimate of the extent and amount of floating plastic at an ocean-basin scale, but the data also confirm that basic ocean physics explains why the plastic accumulates in this region so far from shore,” Law said.

Now that the Pacific and Atlantic Garbage Patches are located, are there more? Maximenko's model suggests there ought to be similar patches in the south Atlantic, the South Pacific and the South Indian Ocean. All are in remote parts of those oceans where ship traffic is light. That may explain why they haven't yet been found.

But if they exist they also may simply have a lot less trash in them, since the Southern Hemisphere produces less plastic trash than the Northern Hemisphere.

For more information see NOAA's page on marine trash, or see here for more about Maximenko’s model.

The paper: Kara Lavender Law, Skye Morét-Ferguson, Nikolai A. Maximenko, Giora Proskurowski, Emily E. Peacock, Jan Hafner, and Christopher M. Reddy: Plastic accumulation in the North Atlantic subtropical gyre, Published Online August 19, 2010, Science DOI: 10.1126/science.1192321.

© Jan TenBruggencate 2010

Thursday, August 19, 2010

Hurricane Cannon tested at Diamond Head Crater

University of Hawai'i researchers have built a specialized cannon that fires two-by-four timbers into walls and doors.

(Image: The University of Hawai'i's Hurricane Cannon, within the “windborne debris test facility” inside Diamond Head Crater. Credit: Ian Robertson.)

They will use it to test the ability of Hawai'i structures to withstand the kinds of forces generated by hurricanes. The first test is scheduled today (Aug. 19, 2010)

Anyone who has seen the power of items driven by hurricane winds knows what that's about. Entire roofs skating through the air like a Frisbee. Sheets of corrugated roofing whizzing across the landscape at shoulder level. Stuff embedded in solid walls.

The cannon is the work of Mānoa professors Ian Robertson and H. Ronald Riggs of the Civil & Environmental Engineering Department. Their device, which looks like nothing so much as a giant potato gun, was constructed with support of Hawai'i State Civil Defense.

It will fire nine-foot two-by-fours at up to 80 miles an hour.

It's not the first such cannon to be developed. Some of the early work in the field was performed at the Texas Tech University at Lubbock. Among their findings was that a “2 × 4 in. plank perforates the face shell of unreinforced concrete masonry at about 65 mph.”

One target of the Hawai'i research will be the kinds of wall systems proposed for safe rooms. These are armored rooms that can be built into a home, where residents can be sheltered from the kinds of flying debris that would readily smash through windows and plywood walls.

Safe rooms on Kauai, where the community has recent experience with hurricanes Iwa and Iniki, qualify homes for property tax breaks.

The goal of the Hurricane Cannon with respect to safe rooms is to work with structural engineer Gary Chock of Martin & Chock to help develop economical designs for safe rooms that can be used in Hawai'i homes.

Another goal is to publicize the cannon, in hopes its work will help convince people to build safe rooms.

“By informing residents of Hawaii about the potential threat of windborne debris during future hurricanes, it is hoped that this facility will encourage retrofit of existing homes through the addition of opening protection or saferooms. Residents without such protection or whose homes do not have hurricane connectors, will be encouraged to evacuate to state designated shelters,” said a fact sheet issued by Robertson.

"Windblown debris is a major risk to life and limb as well as to property damage during strong-wind events. Ian and Gary are perfectly suited by education and practical experience to study this critical element of public safety," said C. S. Papacostas, professor and chair of the University of Hawai'i Civil & Environmental Engineering Department.

© Jan TenBruggencate 2010

Friday, August 13, 2010

The ocean's color affects heat, storm formation

In the middle of hurricane season, a new study adds a surprising new chapter to the study of tropical cyclones.

It suggests that the color of the water has an impact on storm formation. Greener, more storms. Darker blue, less storm activity.

Entirely bizarre, it seems, until you read further. And then it makes a lot of sense.

Here is the American Geophysical Union's press release on the paper, “How ocean color can steer Pacific tropical cyclones,” by Anand Gnanadesikan, Gabriel A. Vecchi, Whit G. Anderson, and Robert Hallberg, all of the NOAA Geophysical Fluid Dynamics Laboratory , and Kerry Emanuelof the Dept. of Earth, Atmosphere and Planetary Sciences, MIT, Cambridge, MA.

Here's the upshot of this: The ocean's color is affected by how much plant life is in it, and the amount of green chlorophyll impacts how far the sunlight penetrates.

Less chlorophyll, and the sunlight goes deep, heating a lot of the ocean at various depth. More chlorophyll, and the sun penetrates not far, heating up only the surface areas, and making the surface water hotter than it otherwise would be.

What it means is that suddenly the already problematic business of storm forecasting gets even trickier, or, as the paper says, “our results suggest that climate modelers wishing to make statements about tropical cyclones need to be extremely careful in describing the physics of the upper ocean.”

In the past, there have been suggestions that a warmer global climate could increase water temperatures, making storms more frequent and stronger. But very recent research suggests that the amount of plant life in the oceans may be crashing, arguing under Gnanadesikan paper for fewer storms.

For more on this research, see our immediately previous post at Raising Islands.

© Jan TenBruggencate 2010

Monday, August 2, 2010

Crashing ocean productivity: what's it mean?

Climate change appears to be messing with the fundamental dynamics of ocean productivity.

The oceans are humanity's great dump. Our plastic bottles, pesticides, industrial chemicals and so much more end up polluting the oceans. Just look at any storm drain in the Islands that's marked with a fish and a warning that anything dumped on the street flows to the sea.

Increasingly, climate change is also polluting the oceans. There have been plenty of reports of increased ocean temperatures, rising sea levels, threats to heat-intolerant coral reefs, the acidification of the oceans.

But a new threat is in many ways even darker. Phytoplankton, the tiny forms of plantlife that are base of the marine food web, have declined 40 percent in the past 60 years, according to a new study.

Here are a couple of reports on the Nature article that prompted the concern. NatureNews. Reuters.

It is still not clear what the most important causes of this decline are—it could be secondary to warming and acidification, which in turn are linked to increased carbon dioxide in the atmosphere. It could be something entirely different.

And it isn't entirely clear what the impacts might be, although one impact of reduced productivity is poorer fisheries. Fisheries are being hammered from many directions. Rising temperatures, overfishing, acidification and the rest are just some of them.

The conservative Heartland Institute sought to downplay the research with a series of off-point studies. Those studies argue that increased carbon dioxide ought to increase phytoplankton growth, and therefore there's no problem.

That's a little like arguing that driving at 100 miles an hour is better for the environment than 50 because it gets you there faster. The faster part is true, but it's irrelevant to the environment part.

The key issue here is that, as Heartland correctly says, this is just one study. Other researchers will follow up and determine whether its conclusions are valid.

If so, it ain't good.

© Jan TenBruggencate 2010