Earth Science and Climate Monitoring | After Typhoon Haiyan, Hunt for Forecasting Improvements Continues
SAN FRANCISCO — Meteorologists continue to make steady progress in their efforts to warn communities of approaching tropical cyclones. Even those warnings, however, were not enough to prevent the historic levels of death and destruction brought about by Typhoon Haiyan, which struck the Philippines Nov. 8, killing more than 5,000 people and leaving millions homeless.
“The track forecasts for Haiyan were pretty accurate,” said Mark DeMaria, technology and science branch chief for the U.S. National Oceanic and Atmospheric Administration (NOAA) National Hurricane Center. “It’s just the storm was so intense.”
With the help of increasingly sophisticated computer models and a growing array of airborne and space-based instruments, researchers have made dramatic improvements in their ability to predict the path of tropical cyclones. “Now, we have the ability to forecast five days in advance what 30 years ago we could only do two days in advance, which is a huge improvement in terms of giving people lead time for evacuations,” DeMaria said.
One satellite mission that has contributed to those gains is the Tropical Rainfall Measurement Mission (TRMM), a joint project of NASA and Japan Aerospace Exploration Agency (JAXA), launched in 1997. TRMM’s Precipitation Radar has provided researchers with the ability to peer into clouds while the satellite’s Microwave Imager has offered detailed observation of rainfall patterns. After 16 years, however, TRMM is showing signs of its advanced age including battery and instrument problems. Even if its instruments continue to operate, TRMM is likely to run out of fuel sometime between 2014 and 2016, said Scott Braun, a research meteorologist at NASA’s Goddard Space Flight Center in Greenbelt, Md., and principal investigator for NASA’s Hurricane and Severe Storm Sentinel (HS3) mission, which uses unmanned aircraft to study hurricanes and tropical storms.
TRMM’s successor, the joint U.S.-Japan Global Precipitation Measurement (GPM) mission, is designed to operate as part of a virtual constellation of satellites operated by NOAA, France’s CNES, the U.S. Defense Department, the European Organization for the Exploitation of Meteorological Satellites and the Indian Space Research Organisation. The GPM spacecraft, also known as the GPM Core Observatory, is scheduled for launch in late February on a JAXA H-2A rocket from Japan’s Tanegashima Space Center.
The Goddard-built satellite will feature the Dual-frequency Precipitation Radar developed by JAXA and Japan’s National Institute of Information and Communications Technology; and the Global Precipitation Measurement Microwave Imager built by Ball Aerospace & Technologies Corp. of Boulder, Colo. Both instruments are significantly more advanced than their predecessors onboard TRMM, Braun said.
Researchers will use data gathered by GPM’s microwave imager to improve models of tropical cyclone activity, which in turn will lead to improvements in storm intensity forecasts. Those intensity forecasts have improved little in two decades because researchers lacked the observations they needed to gain a detailed understanding of the processes taking place inside storms. Once researchers better understand those processes, they can translate them into forecasting models, said Bjorn Lambrigtsen, a microwave instrument scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
GPM also is designed to provide greater coverage than TRMM, surveying latitudes from 65 degrees north to 65 degrees south of the equator. In contrast, TRMM is focused on the tropics, providing imagery between latitudes of approximately 35 degrees north and 35 degrees south of the equator.
The NASA-NOAA Suomi National Polar-orbiting Partnership launched in late 2011 already is helping meteorologists observe tropical cyclones. Suomi features the Visible Infrared Imaging Suite (VIIRS), a scanning radiometer built by Raytheon Space and Airborne Systems of El Segundo, Calif., designed to obtain imagery even in conditions of very low light.
“You basically can get a picture that looks like it’s daytime even with just a little bit of moonlight,” DeMaria said. “That has the capability to help forecasters analyze the structure and current position of a storm at night.”
Another Suomi instrument, the Advanced Technology Microwave Sounder, is providing information on atmospheric temperature and atmospheric moisture around the world. That information feeds into the complex computer models used to predict the path and intensity of storms, DeMaria said.
Further advances in tropical cyclone research and monitoring are likely to come from the next generation of Geostationary Operational Environmental Satellites (GOES), NASA and NOAA officials said. The GOES-R spacecraft scheduled for launch in early 2016 features the Advanced Baseline Imager (ABI) built by Exelis Geospatial Systems of Rochester, N.Y. ABI is designed to offer higher spatial resolution than imagers on currently orbiting GOES satellites.
“That will help forecasters get a feel for where the storm is now and how it is interacting with the jet stream,” DeMaria said.
GOES-R data also will be assimilated in atmospheric models, he added.
An instrument that was not featured on previous GOES missions but is featured on GOES-R is the Geostationary Lightning Mapper, built by Lockheed Martin’s Advanced Technology Center in Palo Alto, Calif. That instrument is designed to observe lightning activity occurring between clouds or from clouds to the ground.
“Being able to know all the lightning going on in the storm is going to help us improve storm intensity forecasts,” DeMaria said. “That is a brand new capability we will see in roughly two years time.”