STUDYING AND PREDICTING TYPHOONS

HISTORY OF STUDYING STORMS

Madeleine Nash wrote in Smithsonian magazine, “When Christopher Columbus arrived in the New World, he heard its native inhabitants speak fearfully of the storm god they called Jurakan. On his fourth voyage, in 1502, the Italian explorer and his ships weathered a hurricane that destroyed much of the settlement his brother Bartolomeo had founded six years earlier at Nueva Isabela, later rechristened Santo Domingo. "The storm was terrible," Christopher Columbus wrote, "and on that night the ships were parted from me." His ships reassembled afterward, but some 25 other ships in a fleet launched by the governor of Hispaniola foundered in wind-frenzied seas. [Source: Madeleine Nash, Smithsonian magazine, September 2006]

“The scientific study of hurricanes leapt forward in 1831, when William Redfield, a self-taught meteorologist trained as a saddler, finally grasped their nature. In an article published in the American Journal of Science, Redfield described patterns of damage wrought by a powerful storm that had swept through New England ten years earlier, after passing directly over the New York metropolitan area. In one part of Connecticut, he noted, trees appeared to have been blown down by southwesterly winds; in another part, by winds from nearly the opposite direction. Redfield nailed down the rotary nature of a hurricane's eye wall, a churning cylinder of wind circling a calm center. [Ibid]

“A systematic effort to understand these storms dates to 1898, when President William McKinley directed what was then the U.S. Weather Bureau to expand its rudimentary network for hurricane warnings. The impetus was the outbreak of the Spanish-American War. "I am more afraid of a...hurricane than I am of the entire Spanish Navy," McKinley reportedly said. In 1886, a record seven hurricanes hit the U.S. coast; one completely destroyed the thriving port city of Indianola, Texas. The year 1893 was almost as bad; six hurricanes hit the United States. One came ashore near Savannah, Georgia, overwhelming the low-lying Sea Islands off the South Carolina coast; another devastated the island of Cheniere Caminanda off the Louisiana coast. In those two storms alone, 4,500 lives were lost. [Ibid]

“Over the next half century, forecasters relying on observations of winds and pressure taken by an expanding network of ship and ground-based weather stations struggled to provide hurricane warnings to vulnerable populations. They often failed. In 1900, a hurricane burst upon the unsuspecting citizens of Galveston, Texas, killing 8,000 to 12,000. In 1938, people stood along Long Island's Westhampton Beach marveling at what they thought was an approaching fog bank, only to realize, too late, that it was the storm-seized ocean heaving up. Twenty-nine people died. [Ibid]

“World War II propelled hurricane science into the modern era. In July 1943, Army Air Forces pilot Joseph B. Duckworth---on a dare, it is said---flew through the eye of a hurricane as it neared the Texas coast; he did it again a couple of hours later as weather officer First Lt. William Jones-Burdick took measurements at 7,000 feet, inside the storm's eye. In February 1944, the Joint Chiefs of Staff approved the first of a series of hurricane missions by Army and Navy aircraft. Later that year, military planes gave chase to a storm that came to be known as the Great Atlantic Hurricane, following it as it roared up the East Coast, taking aim at New England. All along the storm's path, radio newscasters blared out warnings. Of 390 deaths, all but 46 occurred at sea.

After the war, the U.S. Weather Bureau---renamed the National Weather Service in 1970---established a formal program of hurricane research. To study these formidable whirlwinds, flights continued to transport scientists through turbulent eye walls and the eerie stillness of the eye itself. In the 1960s, earth-orbiting satellites began providing even higher observational platforms. Since then, forecasters have progressively narrowed "the cone of uncertainty," the teardrop-shaped blob that surrounds their best predictions of where a hurricane is likely to go. At 48 hours, track forecasts are now "off" on average by just 118 miles; at 24 hours, by less than 65 miles, both significant improvements over 15 years ago. Despite these advances, hurricanes undergo sudden surges in power that are easy to spot once they start but dauntingly hard to predict.

Studying Typhoons

To study storm intensity, scientists use models that reduce storms to grid of points and study how these points interact. The smallest resolution for a point on these models is about one square kilometer. Most are about a hundred square kilometers. Thus far these models have proved to be poor predictors of intensity because the features that cause storms to gain and lose intensity are often smaller than a square kilometer.

To gain insight into typhoon and hurricane dynamics, scientists are studying how moist and dry air affect the eyewall; looking closely at the eye itself and the vortexes that sometimes form there; and setting up wind detectors on the ground in places were storms hit and measure the flow of air as it passes through building or us funneled by mountains and valleys.

Storm intensity used to be predicted solely on the basis of atmospheric conditions. More accurate predication models now feature information on ocean surface temperatures. These days oceans temperatures are studied with probes that no only measure sea temperatures at the surface but also measure currents and temperatures at deeps up to 3000 feet to gain insights into how movements of warm and cool water affect storms.

About a dozen supercomputers around the globe have storm predictor models. There is even a supercomputer in Florida that evaluates all the data from all the supercomputers to see which models are the best predictors and best match reality.

In 2005 officials deployed seven buoys in the Gulf of Mexico, the Atlantic Ocean and Caribbean Sea to collect data to track hurricanes. Eight more were dropped into the Caribbean in 2006

Observing Typhoons

Close range information on hurricane is gathered by planes that fly over the storms, into the eye of the storm and drop probes called dropsaonders that look like a baton attached to a parachute and measure wind speeds and direction, humidity, heat and pressure as the descend through the storm. They take about 15 minute to descend from 40,000 feet to the sea. Scientist also use airborne devices launched with weather balloons whose movements can be tracked with Global Positioning System (GPS) systems.

American scientists studying hurricanes use NOAA P-3 turboprop planes to fly into the eye of Atlantic hurricanes. They generally only study conditions several thousand feet above the worst turbulence and use dopplar radar to observe the bands of rain as part of the Hurricane Rainband and Intensity Change Experiment (RAINEX). Often times two or three ate flown at the same time to get a big picture view of the storm.

These day robotic aircraft are being used to fly right into the heart of the storm. In 2005, an 28-pound aircraft called the Aerosonder flew into the middle of a tropical storm and stayed there for 10 hours, flying as low as 1,200 feet, measuring wind speeds, moisture content of the air, heat and pressure, and relaying information at a rate of twice a second. One its primary mission was how observe how heat form the ocean was transferred to the storm.

Observing Typhoons with Satellites

Typhoons are photographed from space using weather satellites. Before the existence of these satellites determining where a typhoon was going, where or when it would strike was often speculation at best.

The Tropical Rainfall Measuring Mission (TRMM) satellite was launched in November 1997. It has a unique “rain radar” that probes like a CT scan deep into clouds with microwave, infrared and lightning sensors, allowing scientists accurately see the eye and powerful updrafts to investigate how typhoons and other storms form as well study other things like global warning and the El Nino affect and rainfall patterns around the globe.

One scientist told the Washington Post, “TRMM’s radar can peer inside tropical storms to watch them evolve...A lot of times you’ll see just see a ball of white cloud, but TRMM can go to the core, see the eye wall start to develop: Is it intensifying? Is it getting better defined? Is it falling apart.” TRMM is especially good at detecting fast rising columns of air that act as energy pumps for the whole system.

NASA almost let TRMM satellite fall to earth rather spend the relatively paltry sum of $28 million to keep it aloft, Scientists were outraged that such a valuable tool could be allowed to fall to earth just like that. One of the reasons for the lack of money was a shift funds to Bush’s Mars program. Funding came through at the last minute.

Tracking Typhoons

Typhoons cause much less loss of life than they used, in part because of effective warning system that help people get out of harm’s way. Scientists have gotten good at predicting the track of storms but still have difficulty predicting the damage because they have difficulty determining a storm’s intensity at a given spot and figuring how long it will stay at that spot.

Typhoons are relatively easy to track because they are often directed by high pressure system that move the storm in easy to predict patterns. Storms are generally carried westward from the places they were formed by tropical easterly winds. As they head northward they are more influenced by the jet stream and the prevailing westerly winds. The presence of land and winds in the upper atmosphere going different directions than those on the ground can disrupt the storm itself and make its movements more unpredictable.

Predications are made by gathering data from satellites, models, and other data such as that from aircraft that fly into the eye and plug all this information into several supercomputer storm simulators to get give information on the track, strength and damage. Predications are given in the form of 24 hour, three day and five day projections.

Studying Typhoons from Planes

The P-3 Orion is a modification of the submarine hunters built in the 1960s for the U.S. Navy. Two fly scientists in and out of some of the planet's mightiest storms, including Hurricane Katrina as its engorged eye neared landfall. [Source: Madeleine Nash, Smithsonian magazine, September 2006]

Joel Achenbach wrote in the Washington Post: “For data collection, NOAA relies primarily on a couple of P-3 four-engine turboprop planes, ideal for hunting submarines or plowing through a soggy tempest. The planes sprinkle the storm with dropsondes, foot-long, 3.5-inch-wide probes that parachute to the ocean while dutifully beaming data back to the plane every half-second. The plane's computers process the data, which is then transmitted to a satellite dish in Delaware and eventually to the NOAA database and the National Weather Service Central Operations Center. [Source: Joel Achenbach, Washington Post, September 17, 2003]

NOAA also has a Gulfstream G-IV, which is basically an executive jet emblazoned with the strangely undramatic words "United States Department of Commerce." Also scouting the storms are hurricane hunters from the U.S. Air Force Reserve Command's 53rd Weather Reconnaissance Squadron. Satellites peer down from space, and various weather stations and isolated weather balloons accrete still more data, all of which eventually wind up in various computer models.

A hurricane ultimately can't be reduced to a number and a few statistics. It has its own grandeur and aesthetic grace. Frank Marks, a meteorologist with the Hurricane Research Division of the National Oceanic and Atmospheric Administration, Marks, who flies into hurricanes about as often as other folks get their hair cut, savors one moment in particular. "When you get inside the eye, it's amazing. You're in clouds all the time, and it's dreary, and you're in rain, and all of a sudden you break out" -- into the eye -- "and it's beautiful. It's an existential experience."

Predicting Typhoons in a Given Season and Studying the Birth of Hurricanes

Seasonal forecasts for typhoon and hurricane numbers are largely based on the analysis of sea-surface temperature s in areas where typhoons and hurricanes form, as well as wind conditions and other factors such as the strength of high-level winds that can inhibit large storm formation. In 2005, when the Atlantic basin produced 28 tropical storms and 15 full-blown hurricanes, water temperatures near Africa, where these storms originate, were among the highest ever recorded. Among those who pay close attention to the forecasts are insurance companies.

Marc Kaufman wrote in the Washington Post: “From bases in the Cape Verde Islands and in Dakar, Senegal, researchers have tracked, measured and analyzed some of the 60 waves that every year come off West Africa in the late summer and head toward the Caribbean and North America, carried by trade winds. NASA has outfitted a DC-8 jet with advanced atmospheric-research instruments and flown it through tropical waves to take a wide range of measurements. [Source: Marc Kaufman, Washington Post, August 7, 2006]

Officials said that a NASA team had studied the phenomenon in the mid-1970s but in 2006 the research moved up a notch because of newer instruments. Sensors on the aircraft measure the sizes and shapes of clouds and airborne particles, wind speed and direction, rainfall rates, and atmospheric temperature, pressure and relative humidity. They also study air patterns before and after the waves move through. Imaging from NASA's fleet of Earth-observing satellites -- which can capture, for instance, the vertical shape of a brewing storm “also have been be used extensively. The research focused on the aspect of hurricane forecasting that scientists say remains most challenging -- how and why a tropical storm develops the intensity to become a hurricane.”

There is considerable interest as well in learning more about how small swirling tropical cyclones merge to become bigger systems -- and sometimes hurricanes."There seems to be a real element of chance involved," Halverson said. "To get large areas of rotating air, you need smaller vortices to act as building blocks. We think that they'll merge if they're close together, but it seems this is where chance comes in. If these thunderstorm clouds are far apart, then they won't merge."

Forecasting Typhoon Tracks and Intensity

Joel Achenbach wrote in the Washington Post: Forecasters say they've made huge strides in predicting a storm's track, but are still struggling to nail down a storm's intensity. And the very nature of a hurricane makes it a bit of a whimsical entity. "The storm is part of a fluid," explains Frank Marks, a meteorologist with the Hurricane Research Division of the National Oceanic and Atmospheric Administration."It's an atmospheric entity. The fluid changes; it's not a billiard ball on the table where you know where it's going to go. Imagine the table was changing while you were shooting." [Source: Joel Achenbach, Washington Post, September 17, 2003]

The most critical forecast is probably the track of the storm. Government meteorologists have become so confident about their ability to predict a storm's path that this year they extended their forecast from three days to five. But even if the storm goes where it looks like it's going, what kind of shape will it be in when it gets there? Isabel was a Category 5 on the Saffir-Simpson scale, then slipped to a 4, then a 3, then a 2. A slander against the storm, issued yesterday morning, was that it was "becoming less organized." Isabel was so shapely and symmetrical in the tropics, with that perfectly edged 40-mile eye, but now in the Temperate Zone may be turning into a squalid old squall, arms flailing, eye swollen half-shut -- a reeling, sloppy, skanky beast of a storm.

Forecasting and predicting storm intensity is very difficult. Forecasters often get the movement and direction of a storm right, but its intensity remains much harder to predict. "We're 15 to 20 years behind when it comes to understanding hurricane intensity compared with hurricane movement," NOAA's Jason Dunion, a hurricane modeler, told the Washington Post. [Source: Marc Kaufman, Washington Post, August 7, 2006]

Computer Models Used to Forecast Hurricane and Typhoon Behavior

Once data is collected it is fed into various models used to predict various things about the storms. Joel Achenbach wrote in the Washington Post: “The models have acronyms like NOGAPS, UKMET and GFDL (according to the NOAA Web site, "NOGAPS is the U.S. Navy's global spectral forecast model with 18 sigma levels, a triangular truncation of 159 waves, parameterizations of physical processes and a tropical cyclone bogussing scheme"). [Source: Joel Achenbach, Washington Post, September 17, 2003]

The models all have their own peculiar biases, their own ways of interpreting the significance of the variables. "There are initial data uncertainties, such that when people analyze the data, they can go one way or another and will get a different forecast," says T.N. Krishnamurti, a meteorology professor at Florida State University. Even just two days from landfall, a forecast will have a margin of error of 100 kilometers, he says.

The FSU hurricane lab creates a "model of models," a "super ensemble" of forecasts, that it then sends to the National Weather Service. By using the consensus of many models, it's possible to reduce the uncertainty to about 50 kilometers. Still, Krishnamurti says, "pinpointing is really difficult -- it's a needle in a haystack."

No model is any better than the data that get dumped in it. NOAA's Marks says that the simple act of determining wind speed can be tricky. The storm intensity is based on the peak one-minute sustained wind at 30 feet, and no plane flies at that altitude through a hurricane. The dropsondes have to take that measurement in the final seconds of their plunge, and they often give wildly variable readings. When a report on TV says a storm has, for example, peak winds of 115 mph, that's just a rough estimate, Marks says. "They're all estimates. Nobody really measures what they're telling you. Usually what they tell you is that they're packing wind. I still don't know what that means. If I was going to pack something, I'd pack underwear," he says.

History of Hurricane and Typhoon Forecasting and Modeling

Joel Achenbach wrote in the Washington Post: “Forecasting has come a long way since 1926, when the Weather Bureau, based in Washington, didn't get around to issuing a hurricane warning to Miami residents until midnight for a storm that slammed into the mainland just six hours later. According to a NOAA history of hurricane forecasting, as a hurricane bore down on Galveston, Tex., in 1934, city officials wired the Weather Bureau for an update, only to be informed, "Forecaster on golf course -- unable to contact." [Source: Joel Achenbach, Washington Post, September 17, 2003]

“Col. Joseph P. Duckworth, according to NOAA, completed the first flight through the eye of a hurricane in 1943, ushering in a new era of aircraft reconnaissance. The first statistical forecast model came along in 1956, and the first weather satellite in 1960. Scientists over the ensuing decades continued to probe and poke hurricanes from every direction, and with each year had more data to work with. In the early 1990s, a series of computer models, such as GFDL (for Princeton University's Geophysical Fluid Dynamics Laboratory), measurably decreased the amount of error in hurricane tracking. But at the same time, the number of people living on or near the coast and in the path of tropical storms has increased dramatically. There's been a race of sorts, precision measurement vs. population vulnerability. [Ibid]

“Frank Strait, a meteorologist with AccuWeather Inc., says there are inherent limitations to computer models. Weather is too complicated to be reduced to an equation, he says: "We take measurements of atmosphere, pressure, temperature, dew points, and so forth, but the thing is, we don't have measurements from every single point on the face of the Earth. Inherently we're not putting a complete set of information in the computer models. As a result, they're not going to come out with a perfect forecast. Which is why we still need meteorologists." [Ibid]

“With each year, however, researchers have more historical data to work with. That has emboldened William Gray, a Colorado State University atmospheric scientist, to make annual predictions of the number and intensity of tropical storms in the Atlantic. His laboratory analyzes some 50 years' worth of data on sea surface temperature, atmospheric pressure, zonal winds (blowing east-west), meridianal winds (north-south) and so on. "We assume the future is going to behave similarly to the past," says Phil Klotzbach, a research associate in Gray's lab. [Ibid]

Image Sources: Wikimedia Commons

Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, The Guardian, National Geographic, Smithsonian magazine, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Wall Street Journal, The Atlantic Monthly, The Economist, Global Viewpoint (Christian Science Monitor), Foreign Policy, Wikipedia, BBC, CNN, NBC News, Fox News and various books and other publications.

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© 2008 Jeffrey Hays

Last updated November 2012

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