Stories tagged modeling

It's Friday. Yes, I know I missed it last week. But it's time for a new Science Friday video.

Science Friday
Science FridayCourtesy Science Friday
This week,
"The latest on the bug beat: To survive floods, fire ants band together to form a raft. They can sail for weeks. But how does the raft stay afloat? Researchers report the answer in PNAS this week. Plus, engineers at Tufts are looking to the caterpillar for inspiration for soft-bodied robots. The problem is that squishy bodies make it difficult to move quickly--but some caterpillars have developed a workaround."
Apr
08
2011

In the public media, the impacts of global warming have been less important than questioning its causes. And at any rate, reports on the impacts have alternately a catastrophic immediacy or an ambiguous, amorphous quality--the latter likely born out of caution due to the former's inaccuracy and tendency to undermine action. But there's room for a third approach--one of reasonability and inquiry.

And in fact, scientists' explorations go beyond the intangible models of earth covered in gradations of 5 colors, which represent average temperature change over the last century. Their work tests changes in the real world with real organisms. This field work generates data that can be used to test and improve the accuracy of the earth systems models we use to predict future change.
Wheat: I do what I want.
Wheat: I do what I want.Courtesy 3268zauber

One such project is literally heating up wheat fields and spraying CO2 over them. The researchers want to find out how global warming and increasing concentrations of CO2 will impact crops. It turns out that plants will react to these changes differently in different latitudes and climes.

For example, plants in warmer climates might grow better earlier in the year only to take a dive once summer temperatures pass a certain range. Plants in cooler climates might thrive with warmer temperatures and increased CO2, whereas tropical plants might suffer from too much heat.

"There is a narrow latitudinal band that could make rising heat beneficial to growers, Kimball concluded. But farther south, especially in Mexico, the implications of the warming mean serious reductions in crop yields."

Climate model: I get better when you validate me.
Climate model: I get better when you validate me.Courtesy Robert A. Rohde

The information gleaned in these plant studies is helping validate and improve existing models of vegetation so that the tools we need to make decisions about climate change are more accurate. One of the researchers in the article implies that we need a lot more of this validation than we do predictions right now. Even so, changes in reporting on climate change's impacts are often due less to increased uncertainty and more to increased information.

So it seems that rather than the impacts of climate change being universally good or bad, they're a little of both in different parts of the world. What can we do to improve communication in the media on this front?

And to take this a step further, given the varying environmental responses to global warming, it is ethical for one country to make decisions about climate change without consulting other countries?

It's Friday, and y'all know what that means. Yup, time for a new Science Friday video.

Science Friday
Science FridayCourtesy Science Friday

This week,

"Many mammals have whiskers but not all whisk. Cats don't. Rats do. To whisk, rats use special muscles in their face to brush their whiskers against an object. From the bending bristles, rats seem to be able to decode an object's shape and texture and Mitra Hartmann, engineer at Northwestern University, wants to understand how. This week, Hartmann and colleagues published a 3D whisker model, which she says will help quantify what information the brain receives from a whisk."

Our very own JGordon drops some knowledge...

Sep
03
2010

WHY?: Clouds are hard to model, so let's show them who's boss.
WHY?: Clouds are hard to model, so let's show them who's boss.Courtesy Paige Shoemaker

Next time you look at the clouds, shake your fist and yell at those jerks for making our lives difficult. You might look crazy, but somebody needs to tell those fools.

While it's relatively easy to model temperature changes over the last century thanks to detailed records, clouds are more tricky to understand because we don't have a similar history of cloud observations, and also because they are ornery. So in order to understand how clouds work, scientists are building a body of evidence to model cloud behavior and help show how clouds will impact our weather as well as our climate in the future. I believe they also plan to show those clouds who is the boss of them.

Hurricane help!
Like a child running loose in a toy store, hurricanes have always been difficult to predict because they can unexpectedly change direction. This confounds plans for evacuation, leading some people to leave areas that are never hit, leading others to stay put and potentially face nasty weather because they don't trust the meteorologist, and leading meteorologists to keep Advil in business. But since the 90s, our ability to predict where hurricanes will make landfall has become twice as accurate. This new prescience is due to the development and use of more accurate models of how clouds work, which is in turn due to better understanding of cloud dynamics and faster computers. How about that, punk clouds?

Intensity, however, remains elusive to model. (Shh, don't let them know we have a weakness!)

Go home, son: If wily Earl thought he could outsmart the meteorologists, then he's in for a schoolin'.
Go home, son: If wily Earl thought he could outsmart the meteorologists, then he's in for a schoolin'.Courtesy NASA

"While we pride ourselves that the track forecast is getting better and better, we remain humbled by the uncertainties of the science we don't yet understand," Schott said. "This is not an algebra question where there's only one right answer."

-Timothy Schott, tropical cyclone program leader for the National Weather Service in Silver Spring, Md.

Hurricane Earl
Despite being a "forecasting nightmare," Earl ended up hitting about where it was predicted to go. This means that the right people have been evacuated to avoid injury and fatality. That's right, stick your tail between your legs, Earl.

Connecting to climate
Short-term events such as hurricanes and other storms are difficult to predict, but climate change is a whole other world of uncertainty--again, thanks to those uncouth clouds. Climate scientists are developing new tools, such as satellite technologies that show how much light different cloud types reflect and models that demonstrate localized cloud processes. These approaches look specifically at certain groups of clouds and their patterns of change to add detail to older, larger models that look at climate over larger scales.

Booyah!: Climate computer nerds prevail.
Booyah!: Climate computer nerds prevail.Courtesy Nic McPhee

The problem with the older models is that they have a low resolution that doesn't accurately represent clouds because the clouds are smaller than they can show. Think of it like Google maps--at the beginning, you're looking at the entire planet, or a whole continent--this is similar to older, low-res climate models. The new models are like zooming in on a city--you can see bus stops, restaurants, and highways. But you have to zoom out to see how these small pieces relate to the larger surroundings. In a similar way, the new high-res models are helping to inform older models--this type of work is called multiscale modeling.

Researchers at the Center for Multiscale Modeling of Atmospheric Processes (CMMAP) are developing this exact type of model. You can read about their advances here. This work is important because it brings insight into questions about whether clouds will reflect or trap more sunlight, which can have a big impact on the rate of global warming. It also helps us understand whether geoengineering projects that alter clouds will really have the intended effect. Plus it's just one more way we can pwn clouds.

Aug
31
2010

This is not climate: It is weather. Also, it is breakfast.
This is not climate: It is weather. Also, it is breakfast.Courtesy Lori Geig
Well, no, I won’t literally shout it into your brain. First of all, I’m writing this in the near past, and it’s difficult to shout in this medium anyhow. Also, even if we were right next to each other at the same time, I’d really be shouting into one of your ears, or possibly into your face. To shout into your brain, I’d need some sort of saw, or a hammer, and I’d definitely need your cooperation. (I’m just that kind of guy.) So the shouting thing is out.

But it’s really important that you understand the difference between weather and climate, or folks are going to take advantage of your confusion. They’ll do it with op-eds and obnoxious little bumper stickers instead of with a hammer, but it will still be unpleasant in the end.

So here’s the thing: weather and climate are not the same.

See, you may say to yourself, “I know the difference between weather and climate. I’m smrt!” And you may very well be smert, but there’s a decent chance that you still let weather fool you into thinking it’s climate. As this article in the NY Times points out, plenty of samart people still confuse the two concepts, or at least use one (weather) to make points about the other (climate).

Let’s be different. Let’s be truly smaret people, and get this cleared up once and for all. Weather is not the same thing as climate.

Weather is day-to-day, climate is year-to-year, or decade-to-decade, or century-to-century. Weather is immediate, and we feel it acutely, so it weighs on our minds. But it isn’t climate, which is so long-term that even very smar people tend to miss the point.

The East Coast had a frigid snowy winter, so global warming must be myth, right? But the Midwest and Russia have been having a hot hot summer, so we must be in the burning grip of global warming, right? No. If either is the case, a cold winter or a hot summer isn’t the evidence for it.

Back in the year 1991, there was a blizzard on Halloween. If was off the hooook! I was a jawa, or something, and I trick-or-treated my way through about two and a half feet of snow. Crazy, right? But does that crazy Halloween blizzard mean that October is a very snowy month in Minnesota? Of course not! Who would even think that?

What if we (Minnesotans) got a couple solid weeks of rain right now, at the tail end of summer? That would be a damp way to spend the Labor Day weekend. But would it mean that Minnesota is on its way to becoming a rainforest. No, no it wouldn’t. A rainy couple weeks, or even a whole rainy summer, is weather. Climate is weather (temperature, wind, humidity, atmospheric pressure, precipitation, etc) averaged out over years and years. I’m sorry if your birthday was ruined by a freak firestorm, but that doesn’t have a thing to do with climate, so stop making that demonstration sign with a picture of your cake melting.

Maybe it seems obvious, but we still tend to use weather as a substitute for climate even when we think we understand it. Consider the concept of “Global Warming’s Six Americas.” A report from Yale University has found that people can be placed into six groups regarding their feelings on climate change: alarmed, concerned, cautious, disengaged, doubtful, or dismissive.

People who fall into the extreme categories, the freaking-out “alarmed” and the denying “dismissive,” typically aren’t swayed by day-to-day weather—they might use it to further their own arguments, but they (rightly) don’t let it affect their perceptions of long-term climate behavior.

Everyone else, the various shades of undecided, however, is influenced by the local weather, often subconsciously.

Say what?! Clever people that we are, we still allow the wrong evidence to influence our opinions on huge, important issues?! We have to be smaearter than that! So whenever your jerky aunt or your shrill uncle are trying to tell you that the Christmas heat wave or the frosty July mornings are evidence for or against global warming, run the information through your own brain, and when your brain tells you that you need to consider years and years worth of information before you can make that call, you can tell them to shove it.

Of course climate is made up of weather—lots and lots and lots of weather—but, as an author of a report on the subject puts it, making generalizations about climate based on weather “is like asserting how the economy is doing by looking at the change in your pocket. It’s relevant, but not that relevant.”

I like to think of it another way, too. Like, in Home Alone, just because Kevin Mcallister’s family called him “such a disease,” and left him home alone that one time, it didn’t mean that they didn’t really love him. To actually switch to a climate of non-love, the Mcallisters would have to call Kevin a disease every day for years and years, and maybe even stop feeding him.

Or just because Hulk Hogan opened Pastamania in 1995, it would be a mistake to say that the nation was in a climate of true pasta-love, let alone pastamania. Far from it.

To say the climate is changing, or not changing, you have to look at the weather data over many years. So do that, instead of forming opinions on whatever is bugging you on a particular day. Don’t be a chump. Be smart.

This cool project, Climateprediction.net, allows you to help with climate research. The site links to a program called Boinc, which allows scientists to use your spare computing power for their research projects. While the project is running, you can watch visualizations of the research as it takes place. In fact, you can help with all kinds of projects--as many as you want.

If you decide to try it, please join our team. We'll see if SMM fans can become one of the top contributors!

Jun
03
2010

Sophisticated forecast modeling tools developed at the Center for Coastal Margin Observation & Prediction (CMOP) were recently used to assist in the rescue of a disabled underwater glider.

CMOP researchers spent two days using a particle-tracking model to predict where and when their glider, nicknamed “Phoebe,” would drift ashore. This helped researchers understand how much time they had to stage a recovery operation.

Rescue planning: This is an example of the particle tracking model used to predict the direction the glider would drift. Red represents the glider GPS signals. Green represents the particle tracking forecast.
Rescue planning: This is an example of the particle tracking model used to predict the direction the glider would drift. Red represents the glider GPS signals. Green represents the particle tracking forecast.Courtesy CMOP

“Once Phoebe became a drifting glider, we treated her as a major piece of scientific instrumentation at risk and an opportunity to test our computer models in a sea emergency,” says Antonio Baptista, director of CMOP. “The forecasting system used for Phoebe is the same that we are currently transferring to the U.S. Coast Guard and NOAA (National Oceanic and Atmospheric Administration) for inclusion in their respective operational and emergency response systems.”

Phoebe is a bright yellow glider that moves through the water, gathering information, and sending satellite signals back to land each time she surfaces. She was sent out on her first mission of the year on April 16, 2010 to collect data in the waters off the Washington coast as a collaborative research effort with the Quinault Indian Nation.

Five days into her mission, Phoebe stopped communicating.

Katie Rathmell and Michael Wilkin, members of the CMOP field team in Astoria, Oregon, waited and hoped to receive a signal from her. Hours passed and still no signal. Then almost 24 hours later, Phoebe called home. She had surfaced and transmitted a GPS signal of her current location.

“We reviewed the files she sent and determined that she had gotten stuck at 8.4 meters below the surface and was unable to come up to the surface,” says Rathmell.

The team theorized that Phoebe got tangled in a kelp bed. After a pre-programmed period of time, she jettisoned her emergency ballast weight, which gave her enough buoyancy to escape the entanglement and surface. But having dropped the ballast weight meant she could no longer dive or maneuver. Phoebe was adrift in the ocean.

Rathmell and Wilkin started talking about how to stage a rescue. The challenge was the gale force winds offshore were making the seas too rough for ships to get out of the harbor. The team would have to wait until weather conditions improved.

Even though Phoebe was disabled, she was capable of transmitting a GPS signal every 30 minutes. This allowed the team to track her location. She was drifting south and getting closer to the Columbia River plume. They were concerned she might get caught in the incoming tide. This would pull her into the river and possibly crash her into the jetty. Currents and winds could also push her onto the beach and the surf could break up the glider. The problem was the team was unsure which direction she would drift.

That is when they made the decision to use CMOP’s modeling tools to help narrow down Phoebe’s potential drifting trajectories, possible threats, and windows of time for a recovery operation.

“The team hoped the weather would break in time for a successful recovery. The models helped predict how much time they had to recover Phoebe,” says Paul Turner, senior research programmer.

The data for the particle tracking comes from the forecast models that CMOP runs on a continuous basis. Turner ran simulations for two days using the winds, currents and tides to predict where Phoebe might end up. He generated graphs that predicted drifting directions in one, two, three and four hour intervals.

“Paul Turner did a very good job of getting the modeling and drifter prediction tools working in a fashion that allowed the data to be useful for us,” says Wilkin.

The forecast model showed that time was running out for Phoebe. The prevailing winds and currents were pushing her closer to shore. It was imperative to rescue her soon.

For several days, the conditions were too dangerous to cross the Columbia Bar and get the glider safely aboard a ship. Then around 10:30 on Sunday morning, the research team received word there was a break in the weather and Captain Dan Schenk from Sea Breeze Charters in Ilwaco, Washington would take them out.

Rathmell and Wilkin boarded the “Nauti-Lady” and took a rough ride over the Columbia Bar en route to Phoebe’s last known location.

Finding Phoebe was a challenge. This time of year there are crab traps set out in the ocean and many of their floats are the same color as Phoebe. The team would spot something on the surface of the water that might be Phoebe but it turned out to be something else.

Then they spotted her tangled up in crab lines and floats. “She was surrounded by kelp, plastic, beer bottles, and all sorts of trash,” says Rathmell. They were successful in getting hold of her, removing the crab lines, and pulling her aboard the ship. The team safely returned Phoebe to shore.

Found!: "Phoebe" was found tangled in kelp and crab lines off the Washington coast.
Found!: "Phoebe" was found tangled in kelp and crab lines off the Washington coast.Courtesy CMOP

“The successful rescue of Phoebe, under difficult sea conditions, is a credit to the team work among the Astoria field team, boat operators, modelers and programmers,” says Baptista. “CMOP’s oceanographic knowledge, field observations, computer models, and cyber infrastructure all came together to allow people to make the right decisions at the right time.”

CMOP will use the lessons learned from Phoebe’s rescue operation to further improve their scientific and engineering infrastructure.

May
26
2010

I enjoy working with our team to develop on-line interactive education activities. We are in the final testing of whose goal is to teach about the balance of global water, land coverage, atmosphere and cloudiness required to create a "liveable planet". If you want to play with it and give us feedback - here is the link:

http://profhorn.meteor.wisc.edu/wxwise/climate/makeplanet.html
The goal is to make a habitable planet by adding enough water, atmosphere and clouds to reach a global average temperature of about 15°C (59°F). You can mix and match, add or remove.

* Drag (and drop) an item from the right side to the left to add that element
* Drag (and drop) from the left are back to the right to remove that element
* HINT You must put at least 3 clouds by the planet!!

There is a timer to see how fast you can make the planet livable.

Best Science Visualization Videos of 2009

This clip is a compilation of videos showing the evolution of a project called “Breaking Waves,” funded by the Department of Defense. It uses numerical flow analysis to tackle the challenge. (see more of the best visualization videos at Wired.com)