NASA experiment stirs up hope for forecasting deadliest cyclones
NASA satellite data and a new modeling approach could improve weather forecasting and save more lives when future cyclones develop.
About 15 percent of the world's tropical cyclones occur in the northern Indian Ocean, but because of high population densities along low-lying coastlines, the storms have caused nearly 80 percent of cyclone-related deaths around the world. Incomplete atmospheric data for the Bay of Bengal and Arabian Sea make it difficult for regional forecasters to provide enough warning for mass evacuations.
In the wake of last year's Cyclone Nargis -- one of the most catastrophic cyclones on record -- a team of NASA researchers re-examined the storm as a test case for a new data integration and mathematical modeling approach. They compiled satellite data from the days leading up to the May 2 landfall of the storm and successfully "hindcasted" Nargis' path and landfall in Burma.
"Hindcasting" means that the modelers plotted the precise course of the storm. In addition, the retrospective results showed how forecasters might now be able to produce multi-day advance warnings in the Indian Ocean and improve advance forecasts in other parts of the world. Results from their study were published March 26 in Geophysical Research Letters.
"There is no event in nature that causes a greater loss of life than Northern Indian Ocean cyclones, so we have a strong motivation to improve advance warnings," said the study's lead author, Oreste Reale, an atmospheric modeler with the Goddard Earth Sciences and Technology Center, a partnership between NASA and the University of Maryland-Baltimore County.
In late April 2008, weather forecasters tracking cyclone Nargis initially predicted the storm would make landfall in Bangladesh. But the storm veered unexpectedly to the east and intensified from a category 1 storm to a category 4 in just 24 hours. When it made landfall in Burma (Myanmar) on May 2, the storm and its surge killed more than 135,000 people, displaced tens of thousands, and destroyed about $12 billion in property.
In the months that followed, Reale and his U.S.-based team tested the NASA-created Data Assimilation and Forecasting System known as GEOS-5 and its NASA/NOAA-created analysis technique using data from the days leading up to Nargis because the storm was particularly fatal and highly characteristic of cyclones in the northern Indian Ocean.