It’s a custom in Taiwan for the faithful to walk at any hour of the day to one of the numerous ornate and colorful shrines representing the domain of various local deities. Upon entering and after paying homage, the devotee, without a lot of ceremony, might pick two flat, palm-sized river stones from a box by the altar kept there as a means of peering into the future. The stones, kidney-shaped with temple symbols painted on one face, are used to ask the gods’ reply to a question of personal importance.
After contemplating the question for a few moments, the visitor cups the stones in a prayerful manner and casts them to the floor, careful to step aside lest his own feet muddle the message from above. If both stones come to rest face down, the gods are not smiling and the answer will be “no.” However, if both or even one of the stones comes to rest face up, the gods are pleased and it’s considered a declaration in the affirmative. Since it’s obvious that the odds will always favor a “yes” answer, it’s probably important to frame the query just right; still, some say tradition holds that if your heart is pure your chances will improve.
I learned of this ritual this past fall, as one of 18 journalists from around the world who were invited to Taiwan as guests of the state to learn how the country is making progress to address climate change and other environmental issues. While we were there, our host introduced us to, and encouraged us to participate in, this ancient temple ritual, as all are welcome to do, and I’m pleased to say each of us left I believe satisfied with the result.
A morning stroll through Peace Park.
During a couple of busy days jam-packed with seminars on science and policy highlighting some of the country’s notable achievements, we learned that far from leaving matters up to chance, Taiwan’s work on climate change issues can best be summed up with two words: modern and comprehensive.
I knew there was a lot more to Taiwan beyond our agenda of very informative seminars and guided activities. So, one evening, as darkness enveloped downtown Taipei, I decided to wind down with a walk along avenues lined with stately palm trees and surreal banyans. I was struck by the myriad illuminated traffic signals and diagrams on the pavement, proposing a complex ballet of maneuvers required to maintain a degree of safety on the streets crowded with all manner of commuters.
Bikers on Vespa motor scooters–the preferred mode of personal transport–numbering in scores or sometimes into the hundreds, streamed by in packs or alone. Whether sporting stylish, color-coordinated headgear or sensible safety helmets and goggles, the individual riders each display an almost reverential respect for the intricate rules of the road. Pedestrians are tolerated, but it can be dicey. Nobody brakes–nor do they swerve. Instead, with no outward warning, cyclists just gently modulate the accelerator up or down, trusting that you’ll take your cue. Fortunately, English translations on the signposts do improve the odds somewhat for observant foreigners. Nonetheless, it was a relief to find my way to a quiet park just a short walk from the main railway station, and not many blocks from our hotel. Because it was drawing late, and the idea to explore the scene in daylight was endorsed by hotel staff, I decided to have a look the next morning to get a small glimpse of what life might be like for regular people in Taipei.
Motorcycle riders waiting for the green light in a pouring rain, Tainan, Taiwan
Two Cities in One
Although it is a very modern city, boasting the second-tallest skyscraper in the world and served by one of the newest and fastest high-speed rail systems on the planet, it’s impossible not to sense the importance of tradition almost everywhere in Taipei.
It’s a compact city, and a crowded one. It seems there are multiple uses for just about every square foot of it. Scooter repair shops populate the areas below roadway overpasses. Small, well-cultivated garden plots buffer floodplains behind levees on the Danshui River. During one of our many journalistic expeditions, we had a chance to tour one of the city’s main wastewater treatment plants. Like the mastermind in a 1960s spy movie, Home-Ming Chen, Ph.D., assistant chief engineer for the Sewerage Systems Office, and Mr. Wen-Cheng Yao, director of the Dihua Sewage Treatment Plant, proudly demonstrated how the workings of the sewage treatment facility had been cleverly hidden in the heart of the city.
Pressing his remote control switch, Chen raised the cover piece of a tabletop mockup, explaining that the baseball diamond, tennis courts, and other popular recreational attractions we could see on the surface camouflaged a sophisticated and highly automated sewage treatment plant humming along 17 meters underground. While leading our group through the cavernous installation staffed by men and women wearing hard hats and work shirts bearing the public works agency logo, he told us that very little goes to waste. The solids, we were told, get reprocessed as construction material for the fast-growing city, and the methane gas generated during the wastewater treatment process gets reused as heating fuel to keep a street-level indoor swimming pool on the site warm enough for the public’s enjoyment year round.
And there is a whole other new city springing up next to Taipei; it’s called New Taipei City. Nothing seems to stand still for very long.
Peace Park in the morning, however, represents an oasis of beauty and calm. With its classic pagodas, serene pools, and winding footpaths, the park provides a tranquil counterpoint to the urgency of doing two things at once under the burgeoning skyline. As commuters alight from the adjacent sparkling and very busy metro station and stroll through the park on their way to work, many stop for a moment to offer prayers at an outdoor shrine. Here and there, within the formal gardens, office workers set down their brief cases and doff their sport coats to perform the elegant cyclical motions and poses of their morning tai chi routines. I watched intrigued as a separate group of about a dozen men and women gathered among the trees and monuments to exercise, under the guidance of a gentleman with a touch of gray hair and attired in a burgundy-colored athletic warmup suit, as he enthusiastically called out movements and postures via karaoke and wireless microphone.
Near me, on a bench, a student of the ehru, an ancient, two-stringed instrument played with a bow, runs through haunting oriental scales, perhaps working out challenging passages of a classic Chinese opera in the open air so as not to disturb neighbors at his apartment complex, who might have different tastes in the arts.
Life here in the shadow of the Presidential Offices proceeds with a calm rhythm that belies the tempest below and above.
Emergency operations are taken seriously throughout the country.
Their Eyes on the Storm
Despite the appearance of calm, Wei-Sen Li, deputy executive secretary of the National Science and Technology Center for Disaster Reduction (NCDR), speaking at his agency’s headquarters, says the island has had to deal with more natural disasters per square mile than virtually any other place on earth. But he also says that few places in the world have the depth of experience dealing with natural disasters that Taiwan has, and few locales have a higher stake in mitigating their fury.
“Taiwan has the highest exposure economically to risk, partly because it has so many high-value assets in the path of potential disaster,” says Li.
This island of 23 million residents, about the size of my home state of Maryland and neighboring Delaware combined, rests at the junction of three major tectonic plates, placing it near the focal point for seismic activity.
“We have earthquakes almost every day,” Li told us matter of factly, without any show of anxiety, while leading our little group of astonished journalists on a tour of NCDR headquarters.
When we entered the NCDR command center, the wall-size video screens displayed a benign generic image. With its array of computer and communications terminals, including a special telephone for the president of the country, the NCDR operations facility looks as if it’s prepared to control a mission into space. Li invited us to take seats at stations that would be occupied by the country’s top safety officials and experts in the event of disaster. To the surprise of our entire group, Li shared the news that there had been a moderately powerful earthquake measuring 4.6 that had shaken Taiwan in the midst of our visit to Taipei. Among our group of journalists no one had noticed, and fortunately, there were no reports of injuries or severe damage, but Li says tremors pose a constant risk.
Weathering a Way of Life
The hints of how seriously disaster risks are taken in Taiwan were everywhere. In addition to NCDR’s sophisticated control center, I noted during our visit to the countryside later on that the buildings display prominent wall markings to indicate where emergency escape slings can be found; these could quickly whisk occupants from the premises in case the earth were to move with a little greater vigor than it had earlier in the week.
The architecture of Lanyang Ecological Museum, a popular destination in Yilan County, tells part of its story of Taiwan’s natural history with a faÃ§ade and roofline tilted at bizarre angles to mimic the effects of tectonic activity on the local landscape. And with no effort made to conceal its structural elements, visitors clearly see its earthquake protection systems of shock absorbers, cables, and resilient supports, integral components of its award-winning design.
Li says that just like earthquakes, tropical cyclones pose a significant risk for Taiwan. Each year, islanders can expect to be hit by three or four typhoon-strength storms. However, that’s not necessarily a bad thing. According to Li, tropical cyclones have historically been counted upon to restore moisture to hillside croplands and to recharge streams, lakes, and groundwater resources that provide drinking water for towns and cities along the coasts.
They can also bring catastrophe.
Everywhere we went in Taipei, our hosts talked about Typhoon Morakot, a storm that brought about the worst catastrophe in the past 50 years in Taiwan. When it struck Taiwan in August 2009, the severity of the storm caught many people by surprise. Rain gauges in some districts registered close to a world-record 3,000 millimeters (nearly 10 feet) of rainfall over the island’s southern mountains during a period of a mere 72 hours.
In Li’s recounting, Morakot behaved at first like a typical typhoon for the area, slicing through the southwest Pacific at a brisk 20 kilometers per hour, but it suddenly slowed to a crawl of less than 10 kilometers per hour as it neared the northern Taiwan shore, while weakening to a Category 2 cyclone. According to Li, however, Morakot, like most cyclones that approach Taiwan, didn’t give urban residents in the northern part of the country much cause to worry. Because of their typically high elevation, coastal cities on the rocky island are at little risk from hazards such as storm surge, and adding to the feeling of security, modern earthquake-resistant structures in the major cities do a pretty good job in handling the battering winds from an approaching typhoon. However, it is often the inland, upland, and rural communities that face the greatest hazards from tropical cyclones; not from wind and storm surge on the leading edge of the storm, but from the rain swirling around within the storm and even from rainstorms dragged overland on the tail end of a cyclone.
After returning to the United States, I spoke with Ying-Hwa (Bill) Kuo, a man who appreciates the impact a typhoon can have on a community. He lived with his parents in rural Taiwan until age six, when the sudden arrival of a devastating typhoon swept away the family farm, forcing them to migrate to town and to seek a new livelihood. This crisis of his childhood, it seems, shaped Kuo’s goals in life too. He is now the senior scientist and director of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) program with University Corporation for Atmospheric Research (UCAR) in Colorado. Kuo specializes in “heavy rainfall prediction,” satellite imaging, and the effects of climate change, and he is frequently in touch with Taiwanese hazard-reduction workers and researchers, including Wei-Sen Li.
To understand and prepare for the possibility of future disasters, researchers and officials like Kuo and Li and many others are taking a close look at Typhoon Morakot, analyzing its every detail to learn how to prevent disasters from becoming catastrophes in the future.
Kuo’s recent work focuses on forecasting heavy rains at a localized scale. He says, “What we were trying to understand is: If such an event were to happen again is there any possibility we might be able to help improve the forecast?”
Li told us that when the tropical depression that would become Typhoon Morakot began taking shape in the west Pacific in early August 2009, it held the prospect for a good rain that farmers had been desperately awaiting. The regular seasonal rains had been faltering for decades, leading to drought conditions in rural areas of Taiwan.
During my stay in Taiwan I also spoke with Professor Shaw C. Liu, Ph.D., at the Research Center for Environmental Changes at Academia Sinica, one of the leading research institutes in the country. He has also looked closely at Morakot and said that despite the farmers’ hopes, the situation exemplified a looming danger: extremes. Liu noted that the irregularities produced by the warming climate are shifting rainfall patterns to the extremes, increasing the likelihood of droughts but also, paradoxically, increasing the hazard of excessive precipitation through the operation of simple physics.
For more detail on this phenomenon, I decided to look into the Intergovernmental Panel on Climate Change (IPCC) reports of recent years and also the research done by Kevin Trenberth of the Center for Atmospheric Research in Colorado.
According to Trenberth, the water-holding capacity of air increases by about 7% for every 1°C (33.8°F) of warming, which he says leads to increased water vapor in the atmosphere. “Hence, storms, whether individual thunderstorms, extratropical rain or snow storms, or tropical cyclones, supplied with increased moisture, produce more intense precipitation events,” writes Trenberth in his article “Changes in Precipitation with Climate Change” in a special 2011 issue of Climate Research. “Such events are observed to be widely occurring, even where total precipitation is decreasing: “˜it never rains, but it pours!'”
Concurring with findings of the IPCC, Trenberth further writes that future tropical cyclones (typhoons and hurricanes) “will likely become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical sea surface temperatures (SSTs). Partly because an intense tropical cyclone takes heat out of the ocean and mixes the ocean, leaving behind a much stronger cold wake than a more modest storm, there may be fewer tropical cyclones on the whole.”
Trenberth’s precipitation article states that storms gather moisture from an area 10 to 25 times larger than the area of precipitation, concentrating the rain evaporated from a large area into a small one. He says moisture convergence in storms would be increased as the storms intensify. The heat liberated by condensation would then feed energy back into the storm, and that this increase in latent heating “can invigorate the storm and further increase moisture convergence,” which can lead to increased precipitation.
Professor Ben Jong-Dao Jou, Ph.D., the executive director of Asia-Pacific Economic Cooperation (APEC) Research Center for Typhoon and Society, echoes Trenberth’s concern that tropical cyclones may be acquiring a meaner disposition than normal: “Some years we have more typhoons than others, and in fact there are signs that the total number of typhoons is decreasing.” But, he adds, “The intensity of the storms that we do have is greater–accounting for the damage.” Even more troubling, Jou says, “The top 20 most damaging typhoons have all been in the last five years.”
For an island such as Taiwan with its jagged topography and steep interior, the consequences of “all-or-nothing” precipitation scenarios can be severe. Wei-Sen Li told us than an excess of rain on the steep slopes of the Central Mountain Range covering most of the island can produce devastating landslides or floods, uprooting trees and prying loose boulders. The resulting catastrophic debris flows are powerful enough to wipe out essential infrastructure such as roadways and homes.
COSMIC’S Ying-Hwa Kuo says the initial forecasts for Morakot from Taiwan’s Central Weather Bureau were not scary or extraordinary, but they were aiming at a moving target. He describes the disparity between the forecast and reality.
“They may have said over southern Taiwan they may get 300 millimeters of rain a day, and they thought, “˜That’s already pretty big,’ but then six hours later they corrected it [the forecast] to be something like 500 millimeters; and then a day later they corrected it to be something like 1,000 millimeters of rain.” It’s a lot of rain, but not necessarily catastrophic.
However, Kuo notes, prior to the storm-making landfall, there had been one single model run by forecasters that projected over 2,000 millimeters of rainfall. According to Kuo, forecasters were reluctant to put their trust in this single exceptional prediction that lay so far beyond the norm seen anywhere on the planet. “They said, “˜It’s not possible for reality to produce so much rain,’ and because it was only one single model run, they were not confident that the model was true. In the end they got close to 3,000 millimeters–it was a little bit surprising to most people, including meteorologists.”
Morakot swept over the island during Father’s Day weekend in Taiwan, a time of celebrations and homecomings. The hills above Xiaolin Village had been soaked with stormwater “for two or three days,” says Kuo. The soil could barely hold.
“Then, this last day of heavy rains allowed movement of the land, and they just basically had a mudslide, and the flooding and the mudslide just covered the village,” he told me.
According to NCDR’S Li, of the more than 450 people in the doomed village of Xiaolin, only two escaped with their lives.
Although typhoons are often large enough to cover virtually the entire island of Taiwan, Li says it sometimes rains tremendously on one side of a mountain but very little on the other. He says some method needed to be devised to predict the areas most at risk for these heavy localized rains at practically the neighborhood-by-neighborhood scale for each particular storm, allowing enough lead time to prepare for an emergency.
Kuo says that the need for detailed prediction is clear, but the means are not. “A lot of times people doing hazard mitigation work say, “˜What I really need from you is very accurate rainfall at one-kilometer resolution, at the very minimum one-hour intervals all the way out to 96 hours, for every kilometer over all of Taiwan. Then, I know where I need to put the pump stations, and where I can pump out the water, and I know exactly where to evacuate the people, and I can run my river flow models and estimate where I’m going to have the flooding.'” But, Kuo says, providing such forecasting precision “is just not practical, nor is it possible.”
“They are thinking in the deterministic sense–basically saying, “˜Put a target out at 300 yards and shoot perfectly right into the center all the time.’ It’s not practically possible that you shoot an arrow 300 yards and you always hit right in the target,” says Kuo.
“I always tell people that the real weather is created by god, but the weather prediction model is created by man, so the model has uncertainties. With all this uncertainty, it’s not practical to say “˜Hey, I’ll run one model with one set of initial conditions’ and for the forecast to be perfectly deterministic and perfectly accurate.”
However, Kuo believes it’s time to try something different. Using typhoon Morakot as a test case, Kuo and his research team set out to try an approach to modeling precipitation at the localized scale that explicitly factors in uncertainty.
Mountains of Data
Using the same data available to forecasters when Typhoon Morakot approached, Kuo applied some high-power computer capabilities that were not available to forecasters in 2009. He called the system “cloud resolving ensemble forecasting,” with the idea that it might increase reliability of rainfall predictions on the local scale during massive storms.
“Cloud resolving” techniques are designed to predict where individual clouds might form, how much moisture they will carry, how they will react to the environment and landscape, and finally where and when they will release their precipitation.
Providing data to the model can be complicated business. Research shows that the conditions that can factor in making extreme precipitation predictions can be innumerable, ranging from atmospheric moisture and wind conditions to barometric readings, temperature, and terrain features such as mountains or hills–even down to the very tint of the soil. For example, in a study entitled Sensitivity of Orographic Moist Convection to Landscape Variability, which dealt with the 1996 Buffalo Creek flood in Colorado, researchers found that an area that had been burned in a fire “seemed to become a magnet for heavy rain” during a particular storm. They reported, “Model simulations indicated preferred cloud and precipitation formation over the burned region due to enhanced sensible heat flux from the darker soil and to low water content in the soil after the fire.”
In addition to having a wide array of accurate data, a good simulation would also need to represent the physical changes water vapor might undergo at various pressures and temperatures, such as when moist air gets forced over a mountaintop where it encounters cooler air.
By running a large number of simulations while allowing some variance to emerge in the models, ensemble forecasting is designed to tease out the probability that any scenario in particular might develop during the storm.
According to Kuo, “Some people say, “˜Shouldn’t you always be using one model?'” But he disagrees, saying “Sometimes the model is wrong, even if the model is producing such a huge amount of rainfall the forecaster doesn’t have the confidence that it’s going to materialize.”
He added, “Having an estimate of the confidence–the skill of the model is important–that can’t be found by one single model run, you have to have some kind of a probability forecast, and that can only come from some kind of ensemble forecast.”
Filling the simulations with the appropriate data and equations to represent physical processes is only part of the challenge; there is also an x factor of uncertainties that can never be nailed down precisely.
“We are always going to have uncertainties in the model initial conditions. For example, if you want to run the model at four kilometers resolution as we do in our model, that means every four kilometers you need to have a value for temperature, for water vapor, and for pressure.” Kuo says that data is not always easy to get.
“Radiosondes are usually 300 to 400 kilometers apart, and satellites don’t always go through the region where you need to be, so we wouldn’t be able to have perfect knowledge of initial conditions for the model. Moreover, some of the observations can be in error.” In addition, he says, “When you make a limited area model you also need the boundary conditions from the global model.” Kuo says this boundary condition data from global forecast models representing what’s going on in the atmosphere and terrain just outside the forecast area “also have their uncertainties.”
Kuo adds there can also be “uncertainties in the model physics.” And the universe supplies an additional complication that practically defies explanation. Kuo notes that in a storm, “there is always some randomness. You’ve heard about the chaos theory–because it’s a nonlinear system, very small changes can lead to some big changes.”
Kuo’s team ran simulated typhoon Morakot scenarios 60 times using 10 hours of clock time on some of the fastest computers in the United States at the Texas Advanced Computing Center. “It’s very expensive,” says Kuo.
Wei-Sen Li leads a tour of Taiwan’s National Center for Disaster Reduction.
Random Acts of Nature
Several of the simulations predicted light precipitation or rain scattered in various parts of the island–the same kind of error that forecasters had experienced during the actual storm. However, almost exactly on cue on the simulated time scale, and contrary to the weather bureau predictions during the actual event, most of the members of the ensemble generated rainfall for southern Taiwan well above the norm, and close to the range of what occurred in the real-life storm; several members virtually pinpointed the exact location that suffered the worst.
“That particular spot on the southwest part of Taiwan had already received a lot of rain before the typhoon made landfall, and it continued to produce rainfall during the time the typhoon was on top of Taiwan and still continued to receive a lot of rain even after the typhoon had left Taiwan. In fact, the analyses show most of the rain took place after the typhoon had left Taiwan,” says Kuo.
The simulations showed the status of the monsoon played a role, as did the slow development of a new typhoon out at sea, and finally the shape of the terrain also played a major role in where the deluge struck.
“For this event to have happened, you have special conditions that just happened to be all in sync. People say in the case of an aircraft crash usually you have about 10 different things go wrong, and one leads to the other. For example, for Morakot to produce such a huge amount of rainfall over that one particular spot it just happened because of the path of the storm, because of the amount of moisture available, and the fact that the storm is moving very slowly, and the fact that there is a mountain in Taiwan. What our paper showed is that the mountain was critical in focusing the rainfall in the spot where it fell.
“It just happened that that one spot initially getting upslope flow from the northwest direction, because of the typhoon saturation got direct westerly upslope flow, and then when the typhoon left it was getting southwesterly flow that was also upslope,” says Kuo.
Staying a Step Ahead
Professor Liu at Academia Sinica believes climate change is already here and is affecting weather patterns. “Climate change and extreme precipitation are closely linked, and large changes in extreme precipitation are found especially at lower latitudes.” With incidents of excessive rainfall and other extreme weather likely to become more commonplace, he says, the responsible thing to do is to start looking for ways to adapt society to the changes. APEC’s Jou agrees, but adds that it’s important to do it the right way. What will be needed is a “people-oriented approach,” he says, to develop “weather-ready strategies” and to promote “resilience to the impact of natural hazards.”
Kuo says establishing forecasters’ credibility is a major step towards building resilience and saving lives.
“We find a lot of times when you give people the warning that there is going to be a big typhoon coming in and that it’s dangerous, people say, “˜Ah, no. The last typhoon–I survived. Everything should be fine, we can weather it out.’ Sometimes you evacuate people and nothing happens and the people say, “˜Wow, you made me lose a couple of days work,’ and things like that.
“This is saying that instead of one single model telling you that for this particular spot you’re going to get 3,000 mm of rain–if all the models are saying that’s going to happen, you have bigger confidence, because that ensemble tries to develop an envelope for the uncertainties,” giving regular people, and authorities a much better framework for making life-saving choices, he explains.
Wei-Sen Li says there is still a lot of work to be done to supply improved models with accurate data to get the best results. “We need more and more detail,” he says. There are “not enough sensors installed” in places that are hard to reach, especially on the treacherous mountain slopes in the central part of the island. In addition, Li says the modeling exercises could be improved by including “high-resolution terrain data” from those very same locations.
High-resolution forecasting is not an easy job, Kuo says, due to it’s complexity and expense; the United States itself is about five years away from being able to put an operational cloud resolving ensemble forecast system in place.
“For Taiwan, such a model is not operational yet at such high resolution, with so many members, but they like the idea, and I think they are getting bigger computers. And I think, with time, they will be able to do that,” says Kuo.
In the meantime, Li told me his agency is focused on assuring public safety in case disaster does strike. He would like to implement a program to gather the stories and recollections of local people in the flood-risk zones to “identify where losses have occurred in the past,” in order to proactively prepare. He says NCDR would ultimately like to develop a “climate-related flood-risk map” for Taiwan to help guide both emergency planning and recovery efforts. Kuo says his research team is working on a new study to see if ensemble models, like the one that he used to duplicate Morakot’s effects on computer, can be run more economically and with a comparable level of reliability using “a combination of lower-resolution ensembles coupled with higher-resolution ensembles.”Storms will come and go. Yet there’s a good chance that as far as one can look into the future, the ponds of Peace Park will go on providing visitors the feeling of serenity I experienced walking that morning on the pagoda footpath. It’s clear to me that the wider world does not always adhere to the formalized tradition of feng shui, which translates from the Chinese as “wind and water.” Nevertheless, however chaotic things appear, science tells us that wind and water do follow ancient rules of their own, and the challenge for a changing world is figuring out how to use that knowledge.