Wednesday, December 29, 2010

Climate change may not promote hurricane increase

Climate scientists have long known that hurricanes form much more easily when the water is warm.

In the past, they’ve told me the threshold temperature for promoting more tropical cyclone growth is about 28 degrees Centigrade, which is about 82 degrees Fahrenheit.

(Image: The average tropical sea surface temperature (black) and an estimate of the sea surface temperature threshold for convection (blue) have risen in tandem over the past 30 years. Credit: IPRC/SOEST/UHM.)

But does that threshold temperature change with a warming climate? New research suggests it does, which seems like good news for Hawai’i.

Researchers Nat Johnson and Shang-Ping Xie at the University of Hawai`i at Manoa’s International Pacific Research Center write in the journal Nature Geoscience that the threshold seems to rise along with climate warming.

They compared tropical ocean thunderstorm frequency with tropical sea temperatures over a 30-year period. Their finding was that the two measures track each other closely, with the threshold rising along with sea surface temperature at about a tenth of a degree Centigrade per year.

“The correspondence between the two time series is rather remarkable… The convective threshold and average see surface temperatures are so closely linked because of their relation with temperatures in the atmosphere extending several miles above the surface,” Johnson said.

The scientists say their research seems to indicate that this trend will continue.

What that means for the Islands is that warming climate does not necessarily mean more hurricane-type storms for Hawai’i—at least not purely because the water is warmer. One of the fears about climate and hurricanes has been that if the threshold didn’t rise, it could mean the water would be above the threshold longer each hurricane season, and we would be at greater risk.

N.C. Johnson and S.-P. Xie, 2010: Changes in the sea surface temperature threshold for tropical convection. Nature Geoscience, doi:10.1038/ngeo1004.

©Jan TenBruggencate 2010

Friday, December 24, 2010

Musings on powering the family car: Gas, electric, pedals?

Imagine the responses if all cars were electric and someone were trying to sell a gasoline-powered vehicle.

(Image: The electric Hungarian concept car Antro, which you can pedal into the garage if your battery runs out, and which splits into two cars for two-commuter households. Source: Antro Vehicle Development Public Benefit Company.)

What would folks say about gasoline cars?

“Gasoline? They can make fuel-air bombs out of that. It’s explosive! You’re going to pour that stuff down a tube and carry it around in your car? That's nuts! What about a collision?”

“Every city’s going to have dozens of gasoline stations with underground tanks filled with explosive liquid that could also leak and pollute groundwater? I don’t think so.”

“Internal combustion engines? They only operate at 25% efficiency. Enormous amounts of their energy are lost as heat. Makes no sense. They’re noisy. They stink. They pollute. You could kill yourself if you left one running in a closed garage.”

And so forth.

A fellow named Robert Llewellyn operates a video podcast on electric cars called Fully Charged. While driving a $2 million Honda hydrogen fuel cell-electric car, he had this comment:

“The internal combustion engine is just a clunky old bit of Steam Age technology. Pistons, crankshafts, valves, all that stuff … It’s clever and complex Victorian technology. It’s not what we should be doing now.”

That said, are there problems with these new post-Steam Age electric vehicles. But there is also any number of solutions for virtually all of them. Here are some pluses and minuses from your federal government.

And some of my thoughts:

Electric cars are expensive. I think of computers. I remember spending $2,000 for one of my first computers some three decades ago. It was quirky, had limited power, was heavy and there weren’t many programs for it. The laptop on which I’m writing this cost a third the amount, is portable, and has capacity and capability that leave that old machine fading like a bad memory. Like computers, they'll be cheaper later.

They’re not sexy and they’re so, well, golfcarty. Let me say two words. Tesla roadster.

Yeah, well, can I fit my kids and the groceries into one? Well, Tesla and Toyota are working on an electric RAV4. AMP has an electric Chevy Equinox now. Shucks, even Range Rover has one.

They’ll never get the price under control as long as they need a ton of batteries for range. Well, battery technology will certainly improve, at least somewhat, which will help. And getting charging stations into parking lots may mean you can fill up any time you stop for a couple of hours—to shop, to eat, to work. And if you charge up when you get home, you’re full at dawn every day. You know, that 300-mile range is mostly so you don't have to fill the car more than once every week or two, not because you drive 300 miles every day.

It’s all so inconvenient. You can charge your iPod and Blackberry and iPhone on a wireless induction plate. No need to even plug them in. Here’s one from Brookstone. And one from Slippery Brick. And there are others. I haven't tried these, but I hear they work fine. Can it work for cars? How about an induction charging plate in your garage. You drive in, and it automatically starts charging. No cables, no fuss. The folks at HaloIPT are among the many that are working on it.

What about long-distance driving? I’ll run out of power and there’s no quick-charge capability. Hard to say how this will work out eventually. Project Better Place is betting on simply driving into a station and quickly swapping your batteries for fresh ones. Others suggest that the induction plate technology cited above can be installed in highways—so you charge as you drive. Here’s a simple discussion on how it works.

The upshot of all this is that you can come up with lots of excuses, but either right now, or soon, pretty much all of them can be answered and put to rest.

Are electric cars the future? Or perhaps hybrids or hydrogen? Or something really quirky like the electric/human-powered Antro, which splits into two cars for two-income commuters and joins back into one car for weekend family outings?

Don't know, but it's clear that the future of alternative transportation is, well, really cool.

© Jan TenBruggencate 2010

Thursday, December 23, 2010

Ulua aukea and `ōmilu: these species sometimes cross

A groundbreaking genetic study of two Hawaiian jacks, ulua aukea and `ōmilu, has reached a couple of interesting conclusions.

One is that while they often behave territorially, their genetic makeup suggests that either occasional long-distance voyaging or spawning characteristics establish each as a single genetic group across the main Hawaiian Islands.

Another is that there are occasional crosses between the species. In the neighborhood of 6 percent of the fish sampled were hybrids.

(Image: An ulua (Caranx ignobilis) from the Northwestern Hawaiian Islands. Credit: NOAA's Coral Kingdom Collection, Dwayne Meadows, NOAA/NMFS/OPR)

The groundbreaking study, published in the January-February 2011 Journal of Heredity, was done by researchers Scott Santos and Yu Xiang of Auburn University in Alabama, and Annette Tagawa of the Hawai`i state Division of Aquatic Resources.

Santos has previously done extensive genetic work on the tiny anchialine pond shrimp of Hawai`i that are known as ‘ōpae `ula. His lab website is here.

First, some nomenclature. These fish are in the family Carangidae, whose members are variously called jacks, trevally, crevalle, cavalli, pompano and a few other names. In Hawai`i, big ones go by the general term ulua and little ones papio.

There are more than two dozen members of the family in the Hawaiian Islands, but this study looked at just two very popular sportfish: Caranx ignobilis, aka ulua aukea, aka white ulua; and Caranx melampygus aka `ōmilu aka bluefin trevally.

The white ulua (which turns black when it gets mad) is generally silvery with black spots, and can get huge—more than five feet long. The smaller `ōmilu is much more colorful, a grayish silver with a hint of gold, with blue spots and blue fins.

The researchers write that “catch data imply that (`ōmilu) is more common than any other jack species on Hawaiian coral reefs.” They had anglers collect genetic samples from fish caught on Kaua`i, O`ahu, Moloka`i. Maui and Hawai`ii Island. The samples were from 33 whites and 58 `ōmilu.

“Based on mitochondrial sequence data, we found no evidence of genetic structure in C. ignobilis and C. melampygus of the high Hawaiian Islands,” they wrote.

“Taken together, we conclude that the absence of genetic structure…is due to the active movement of adult individuals and/or the passive dispersal of eggs and juveniles at frequencies sufficient to homogenize populations in the high Hawaiian Islands.”

The crossing of the species has previously been reported. Santos and his partners, interestingly, found that in all the cases they studied, the hybrids are the result of a female `ōmilu crossing with a male ulua aukea. It’s not clear why.

Maybe male `ōmilu-female aukea crosses can’t survive. Maybe male aukea manage to intrude on `ōmilu spawning events, which occur more frequently simply because there are more`ōmilu .

“In either case, the potential importance of these hybrids to the evolution of the genus Caranx deserves further attention,” the writers conclude.

Source: Journal of Heredity J Hered (2011) 102 (1): 47-54. doi: 10.1093/jhered/esq101

© Jan TenBruggencate 2010

Friday, December 10, 2010

Golden Gooney nesting at Midway; this is a big deal

The dominant big birds of the Northwestern Hawaiian Islands are two albatross species, black-footed and Laysan albatrosses, but an intriguing extended courtship appears to open the door for a third—the exceedingly rare Golden Gooney.

(Image: They take turns. This is the male Golden Gooney incubating its egg in a photo taken Dec. 3, 2010, at Eastern Island in Midway Atoll National Wildlife Refuge. Credit: USFWS John Klavitter.)

This is exciting stuff in the bird world, because this bird is reproducing today on only two small Japanese-owned islands and its numbers remain small.

A pair of Golden Gooneys or short-tailed albatross at this writing is sitting on what is believed to be a fertile egg for the first time in the Hawaiian Islands—at least in recent memory. Their nest is on Eastern Island, one of three flat coral islands within Midway Atoll .

The two birds have been showing up at Midway for several years, initially spending most of their time on separate islets, but occasionally getting together. Last year they made a nest together, but produced no egg. This year they're incubating an egg.

Both of the birds were initially banded on Japan's Torishima Island. The male is an old timer. He was banded as an adult in 1987. The female is a comparative youngster, having been banded as a juvenile in 2003.

Albatrosses generally mate for life, so if both survive, they may begin establishing a small colony of their species at Midway. The birds can live as long as 45 years.

These albatrosses have long arms. Their wingspan of 7.5 feet makes them the biggest bird in the North Pacific. (That's still not much compared to the 10-foot wingspan of the wandering albatross, which is limited to the Southern Ocean, where it spends its life circumnavigating Antarctica.)

The short-tailed albatross' nickname, Golden Gooney, comes from the yellow coloring on its head and neck. The nickname is the more accurate title, because their tails aren't really particularly short, when compared to other albatrosses.

Feather harvesting caused their numbers to crash a century ago, and then in 1939, a volcano eruption on Torishima destroyed the primary breeding grounds, leaving just 10 nesting pairs. Worldwide numbers have now climbed to 2,400 birds, still far below the estimated historic population of 5 million birds.

The Midway egg is not the first there. A short-tailed female is reported to have laid an infertile egg about 20 years ago at Midway. And this year, there are two eggs at Midway's western neighbor Kure Atoll, likely also infertile since there appears to be no male attending the nest.

© Jan TenBruggencate 2010

Friday, December 3, 2010

New UH Research: Warming to rise to high end of climate change estimates

One of the trickiest things in climate modeling is predicting what clouds will do.

That’s important, because heavy clouds reflect solar radiation, causing cooler conditions, and lower cloud cover let solar radiation reach the surface, increasing warming.

(Image: In this IPRC graphic, covering cloud cover over the Eastern Pacific for the past quarter century, the black line represents satellite-observed cloud cover, while the red line represents model-predicted cloud cover.)

New research done largely at the University of Hawai`i’s International Pacific Research Center (IPRC) is suggesting that clouds may thin when it’s warmer, meaning future climate change could be more severe than the most conservative estimates.

The researchers are conservative in their language, but they say their results are worrisome.

“If our model results prove to be representative of the real global climate, then climate is actually more sensitive to perturbations by greenhouse gases than current global models predict, and even the highest warming predictions would underestimate the real change we could see,” said IPRC researcher Kevin Hamilton.

It comes down to clouds.

“All the global climate models we analyzed have serious deficiencies in simulating the properties of clouds in present-day climate. It’s unfortunate that the global models’ greatest weakness may be in the one aspect that is most critical for predicting the magnitude of global warming,” said IPRC scientist Axel Lauer.

Researchers at the center have developed a new cloud prediction model that may help fine tune the predictive process. After developing their new model, they applied it to satellite imagery of the Eastern Pacific over the past 25 years. As the image with this post shows, it seems to be a pretty good match.

The center’s report on the research, “The Impact of Global Warming on Marine Boundary Layer Clouds over the Eastern Pacific—A Regional Model Study,” was written by University of Hawai`I scientists Lauer, Kevin Hamilton, Yuqing Wang and Vaughan Phillips, along with University of Wisconsin atmospheric scientist Ralf Bennartz. It was published in the Journal of Climate.

They call their new model iRAM, which is an acronym for something that already contains an abbreviation: IPRC Regional Atmospheric Model. In their careful terminology, they say that while this research may not be a slam dunk, it’s strongly suggestive that the ball goes through the hoop with some force (to poorly employ a sports analogy.)

“The iRAM results by themselves cannot be connected definitively to global climate feedbacks; however, among the (Global Climate Models) the cloud feedback in the full tropical–subtropical zone is correlated strongly with the east Pacific cloud feedback, and the cloud feedback largely determines the global climate sensitivity," the paper says.

In essence, the work suggests a troubling feedback mechanism may take place with continued warming, in which more warming means less clouds, which in turn means even more warming.

© Jan TenBruggencate 2010