Part 1: The Birth of a Super Typhoon

By mid-afternoon on Nov. 3, 2013, residents of Manila were sweltering. The high temperature peaked at 88 degrees Fahrenheit, but the tropical humidity made it feel like 102. A few scattered clouds above the capital city of the Philippines offered little protection from the tropical sun. A feeble and irregular breeze hardly stirred the giant Filipino flag hanging outside Malaca̱an Palace, where the president lives.

On that same Sunday afternoon, Himawari 6, a Japanese satellite at an altitude of 35,800 kilometers (22,245 miles) above the Pacific Ocean, detected ocean surface level winds blowing at about 30 mph, some 2,500 miles southeast of the Philippines. A day later, winds were clocking in at 40 mph. What had been merely a tropical depression was upgraded to a tropical storm. On Nov. 5, satellite data determined that the wind speed had increased to 75 mph. The tropical depression had become Typhoon Haiyan.

The technology used to track tropical cyclones has made enormous strides since an experimental U.S. satellite, the TIROS 3, discovered a tropical wave forming over the central Atlantic Ocean on Sept. 10, 1961. Two days later, the low pressure system had become Hurricane Esther ‰ÛÒ the first tropical cyclone discovered from space.

The Japanese satellite that detected what would become Typhoon Haiyan, Himawari 6, is in aåÊ geostationary orbit ‰ÛÒ meaning it maintains a position above the equator at about 135 degrees east longitude, monitoring East Asia and the Western Pacific. Himawari (the Japanese word for ‰ÛÏsunflower‰Û) is just one in a fleet of 37 Earth-observing satellites that today shares life-saving information through the World Meteorological Organization (WMO). Data also come from hundreds of ocean buoys, airplanes, and, in the aftermath of disasters, from sources on the ground that use social media to direct supplies and medical aid where it was needed most.

‰ÛÏSpace agencies and other partners are working together to expand the use of satellite images and maps for managing disasters,‰Û says Francesco Gaetani, an expert on disasters for the Switzerland-based intergovernmental Group on Earth Observations (GEO). A primary part of the GEO’s mission is advocating for broad, open data policies and practices among 88 member countries and 67 participating organizations.

‰ÛÏA key system that provides rapid access to satellite data,‰Û explains Gaetani, ‰ÛÏis the International Charter, Space & Major Disasters. The Charter provides a unified system whereby 15 space agencies deliver space-based data to address natural and man-made disaster response.‰Û

The International Charter has provided data to more than 100 countries worldwide since it became operational on Nov. 1, 2000.

Advances in technology have helped researchers better understanding how tropical cyclones like Haiyan form. Typhoons (the scientific name is ‰ÛÏtropical cyclone,‰Û but they’re also called hurricanes or cyclones depending on where they occur) have been likened to giant engines that run on warm, moist air. As heated water-laden air rises over the ocean, an area of low pressure develops, drawing in cold dry air from higher altitudes. The cycle escalates as more energy is absorbed from the warm ocean water. Because a tropical cyclone converts heat energy into wind energy, the warmer the ocean water, the more powerful the resulting typhoon.

According to NASA researcher Edward Olsen, cloud formations in tropical cyclones typically reach the tropopause. Even so, Super Typhoon Haiyan was unusual, said Olsen. In the case of Typhoon Haiyan, an abundance of unusually warm sub-surface water east of the Philippines likely contributed to the storm’s record intensity, says Weather Underground co-founder and meteorologist Jeff Masters. This area of the Pacific already contains the largest volume of warm subsurface water on the planet.

Writing in his blog, Masters recently observed:

Super Typhoon Haiyan tracked over surface waters that were of near-average warmth, 29.5 – 30.5å¡C (85 – 87å¡F.) However, the waters at a depth of 100 meters (328 feet) beneath Haiyan during its rapid intensification phase were a huge 4 – 5å¡C (7 – 9å¡F) above average, judging by an analysis of October average ocean temperatures from the Japan Meteorological Agency. As the typhoon stirred this unusually warm water to the surface, the storm was able to feed off the heat, allowing Haiyan to intensify into one of the strongest tropical cyclones ever observed.

According to Kevin Trenberth, a senior scientist in the Climate Analysis Section at the National Center for Atmospheric Research in Boulder, Colorado, ocean temperatures have increased over the last two decades due to human-induced global warming. ‰Along with that,‰Û Trenberth adds, ‰ÛÏthe air in the atmosphere is warmer and moister. And that’s what fuels all of these storms. The environment that all of these storms are occurring in is simply different than it used to be because of human activities.‰Û

Subsurface ocean temperature is just one element used by researchers at the Climate Prediction Center (CPC) in the U.S. to produce extremely sophisticated weather outlook reports extending from one week to an entire season. A branch of the National Oceanic and Atmospheric Administration (NOAA), the CPC also relies on data from satellites launched by several countries, weather balloons, and ocean buoys. Those data are used by an atmospheric forecast model. Output from that model is analyzed by an automatic tracking algorithm run on computers at the Taiwan Central Weather Bureau (TCWB). Results of that algorithm are then provided to CPC forecasters.

The image to the right, created by the Taiwan Central Weather Bureau (TCWB) on Oct. 29, 2013 five days before the Japanese satellite detected the tropical depression that became Haiyan shows just how accurate the predictions can be.

Matthew Rosencrans is a meteorologist with the CPC. Asked if the areas marked by the blue arrows (which Earthzine added to the TCWB map) correlated with Typhoon Haiyan’s development, Rosencrans warned against drawing any definitive conclusions, especially in the top panel predicting conditions 1-4 days after Oct. 29. The gray area could indicate a low pressure center that simply disappeared before Haiyan took shape. In an e-mail, Rosencrans allowed that the marked area ‰ÛÏis most likely the initial stages of Haiyan’s development, or at least the precursor disturbance that eventually became Haiyan.‰Û

He was more confident about the area marked with a blue arrow in the next map (Day 5-8). That panel, Rosencrans wrote, ‰appears to be more representative of the formation of Haiyan.‰

As Typhoon Haiyan gathered strength and moved toward the Philippines, it was tracked by several satellites, including the Russian Electro-L, operating in a geostationary orbit at an altitude of 35,786 kilometers (21,749 miles) at 75 degrees east longitude.

With the early warning supplied by WMO’s Regional Specialized Meteorological Centre in Tokyo, the Filipino disaster management agency mobilized various agencies and teams throughout the country.

Some 750,000 people were evacuated from the central Philippines. “As bad as the loss of life was,‰Û said the WMO’s Clare Nullis, ‰ÛÏit could have in fact been much, much worse.‰Û

Several factors have been cited as adding to the death toll, including the fact that some evacuation centers collapsed in Tacloban, the city which bore the brunt of Haiyan. It is a matter of debate whether these failure were caused by shoddy construction or by the unprecedented ferociousness of the typhoon’s winds.

With the early warning supplied by WMO’s Regional Specialized Meteorological Centre in Tokyo, the Filipino disaster management agency mobilized various agencies and teams throughout the country.

Some 750,000 people were evacuated from the central Philippines. “As bad as the loss of life was,‰Û said the WMO’s Clare Nullis, ‰ÛÏit could have in fact been much, much worse.‰Û

Several factors have been cited as adding to the death toll, including the fact that some evacuation centers collapsed in Tacloban, the city which bore the brunt of Haiyan. It is a matter of debate whether these failure were caused by shoddy construction or by the unprecedenced ferociousness of the typhoon’s winds.

When Typhoon Haiyan was still gathering strength several hundred kilometers from the Philippines, data from a scatterometer (a type of microwave radar) aboard the Indian Space Research Organization’s Oceansat 2 put the wind speed at 128 mph, according to an algorithm run by NASA’s Jet Propulsion Laboratory (JPL). But a member of the JPL group later pointed out that the scatterometer estimates wind speed with a resolution of about 24 by 24 kilometers and that that the true maximum wind speeds were likely 20 percent higher ‰ÛÒ or about 150 mph. If that figure is correct, Typoon Haiyan was already a Category 4 event according to the Saffir-Simpson Hurricane Wind Scale. It only needed an increase of 7 mph to reach the most destructive level, Category 5.

Here’s how the U.S. National Weather Service describes the effects of a Category 5 hurricane, with sustained winds of 157 mph:

Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.

Less than 24 hours before Haiyan hit the Phillipines, NASA’s Aqua satellite passed over the typhoon at an altitude of just 705 kilometers (438 miles).

Using an Atmospheric Infrared Sounder (AIRS) to measure infrared light, images from Aqua revealed the awesome power of the storm. Clouds at the top of Typhoon Haiyan were minus 63 degrees Celsius (minus 81 degrees Fahrenheit). The storm had reached, and punched into, an important boundary between layers of the Earth’s atmosphere. The troposphere is where virtually all of what we observe as weather takes place. Above it is the stratosphere, with almost no moisture. The tropopause is the frigid, dry boundary region between the two, located at around 17-18 kilometers (10-11 miles) above the Earth’s surface at the equator.

According to NASA researcher Edward Olsen, cloud formations in tropical cyclones typically reach the tropopause. Even so, Super Typhoon Haiyan was unusual, said Olsen.

‰ÛÏAIRS research indicates that Haiyan had one of the largest cluster of tropopause penetrating clouds encountered in the 12 years the instrument has been operational,‰Û wrote Olsen in an e-mail.

By the time Super Typhoon Haiyan made landfall in the early morning hours of Nov. 8, it had been tracked for more than 2,500 miles over the course of several days by researchers and institutions in several countries who collected, analyzed, and shared information about one of the most powerful typhoons in recorded history. As the sea began to rise from a powerful storm surge, the people of the central Philippines braced themselves for the impact of the monster storm.

Coming in part 2: From Devastation to Recovery.

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