Nav: Home

We should use central pressure deficit, not wind speed, to predict hurricane damage

November 08, 2017

The system for categorizing hurricanes accounts only for peak wind speeds, but research published in Nature Communications explains why central pressure deficit is a better indicator of economic damage from storms in the United States.

"Sandy is the classic example. It was a very big storm, but in terms of maximum wind speed it was arguably not a hurricane," said Dan Chavas, an assistant professor of atmospheric science at Purdue University who led the study. "If you looked at the central pressure deficit, you would have expected it to cause a lot of damage. But if you used maximum wind speed, as people usually do, you wouldn't expect it to do the damage that it did."

Central pressure deficit refers to the difference in pressure between the center of the storm and outside it. Pressure and wind speed have been used interchangeably to estimate potential damage from hurricanes for years, but the relationship between them has been a long-standing riddle in tropical meteorology.

Chavas and his colleagues have defined a theory that solves that riddle. Previous work has observed that central pressure deficit depends on maximum wind speed, storm size, and latitude, but Chavas' team has determined why that is.

Scientists could use this theory to calculate peak wind speed if they had numbers for the other metrics in the equation, which could come in handy because wind speeds need to be measured at several points of a storm, making it difficult to get an accurate reading.

The research team tested their theory on two simulations of Earth.

The first used the actual distribution of sea surface temperatures and solar radiation since 1979 to produce conditions similar to real historical climate.

The second simulation produced a very simplified version of the Earth. It had no land, and ocean temperature and solar radiation were the same everywhere. This made the entire planet sort of like the tropics, meaning hurricanes could pop up anywhere - but they still tended to form at low latitudes and move westward and toward the poles, like they do on Earth.

"The idea is that if we test our theory in this very simple world, and then take it to the real world where everything is much more complicated and we get the same results, all that complexity is irrelevant," Chavas said. "People tend to work in different worlds - either the simplified world or the real world, and they don't talk to each other that much. We're bridging that gap."

The limitations of the official scale for hurricane categorization, the Saffir-Simpson Hurricane Wind Scale, have come under scrutiny recently. The wind speed meteorologists settle on is often only an estimate, and it's also highly localized because it depends on a speed sustained for a short time in one location. However, it's popular with the public and media because of its simplicity.

Some have advocated for new systems of categorization, including the Cyclone Damage Potential Index and the Integrated Kinetic Energy index. Both of these systems take into account factors other than wind speed - the idea being that more variables make a scale more valuable.

Boiling down a storm's complexity to a single number may be unrealistic, but there are surely ways to improve the current system. The Purdue team's work shows that central pressure deficit itself may achieve this goal, or at least do a better job than maximum wind speed alone.
-end-


Purdue University

Related Hurricane Articles:

2017 hurricane season follows year of extremes
2016 hurricane season started in January and ended 318 days later in late-November.
Study Offers New Insight on Hurricane Intensification
In a new study, researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science showed the first direct observations of hurricane winds warming the ocean surface beneath them due to the interactions with currents from an underlying warm-water whirlpool.
NASA provides a 3-D look at Hurricane Seymour
Hurricane Seymour became a major hurricane on Oct. 25 as the Global Precipitation Measurement mission or GPM core satellite analyzed the storm's very heavy rainfall and provided a 3-D image of the storm's structure.
NASA sees Hurricane Seymour becoming a major hurricane
Hurricane Seymour was strengthening into a major hurricane in the Eastern Pacific Ocean when the NASA-NOAA Suomi NPP satellite passed over it from space.
NASA animation shows Seymour becomes a hurricane
Tropical Depression 20 formed in the Eastern Pacific Ocean on Sunday and by Monday at 11 a.m. it exploded into a hurricane named Seymour.
Hermine becomes a hurricane in the Gulf of Mexico
Tropical Storm Hermine officially reached hurricane status on Thursday, Sept.
NASA spies major Hurricane Georgette
Hurricane Georgette is a major hurricane in the Eastern Pacific Ocean.
NASA peers into major Hurricane Blas
As NASA satellites gather data on the first major hurricane of the Eastern Pacific Ocean hurricane season, Blas continues to hold onto its Category 3 status on the Saffir Simpson Wind Scale.
NASA gets an eyeful of Hurricane Blas
Satellites eyeing powerful Hurricane Blas in the Eastern Pacific Ocean revealed a large eye as the powerful storm continued to move over open waters.
Early use of 'hurricane hunter' data improves hurricane intensity predictions
Data collected via airplane when a hurricane is developing can improve hurricane intensity predictions by up to 15 percent, according to Penn State researchers who have been working with the National Oceanic and Atmospheric Administration and the National Hurricane Center to put the new technique into practice.

Related Hurricane Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#532 A Class Conversation
This week we take a look at the sociology of class. What factors create and impact class? How do we try and study it? How does class play out differently in different countries like the US and the UK? How does it impact the political system? We talk with Daniel Laurison, Assistant Professor of Sociology at Swarthmore College and coauthor of the book "The Class Ceiling: Why it Pays to be Privileged", about class and its impacts on people and our systems.