Nav: Home

Mechanism modeling for better forecasts, climate predictions

September 18, 2019

As hurricanes grow in power as the climate changes, accurately modeling the interactions between the atmosphere and the ocean grows increasingly important to prepare people to batten down or to evacuate. The many mechanisms of the atmosphere-ocean system -- known as air-sea flux -- make modeling extremely complicated, however.

Qi Shi, a postdoctoral researcher in the Great Lakes Research Center at Michigan Technological University, has created the first detailed analysis of ocean and atmospheric responses to currents, waves and wind. In the article "Coupling Ocean Currents and Waves with Wind Stress over the Gulf Stream" published in Remote Sensing this summer, Shi argues that current numerical models simply don't account for the impact of waves, currents and wind coupled together. This coupling is crucial because without it, models do not accurately represent marine atmospheric boundary layer processes.

"We quantified the impact of this coupling to improve the accuracy of air-sea fluxes, because without modeling currents, there is a constant bias in models," Shi said. "What causes that bias? Missing the full spectrum of feedback mechanisms."

Simply put: Better modeling gives weather forecasters and climate scientists a more accurate picture of what happens where atmosphere and ocean meet.

Feedback Mechanisms

Part of what makes modeling air-sea flux so complicated are the sheer number of feedback mechanisms in the system: To model waves, one must account for surface roughness and wind; to model sea surface temperature, one must account for air-sea temperature differences, water vapor, humidity, evaporation and more. Modeling wind and surface currents are equally complex.

Numerical models solve equations that describe the atmosphere, ocean, and land surface to predict future weather and climate. Interactions among each model component, such as heat exchange between atmosphere and ocean, play an important role in driving both oceanic and atmospheric circulation.

Hurricanes and Climate

Hurricanes are fueled with heat and moisture from the ocean. Ocean currents and waves modify wind shear and surface roughness, which are key variables for calculating the air-sea heat and momentum fluxes. Using a high-resolution, three-way coupled ocean-wave-atmospheric modeling system, Shi determined the role of coupling ocean currents, waves and wind stress in reducing model bias in air-sea flux over the Gulf Stream.

Shi's work is the first detailed mechanism study in the current-wave-stress coupling process, which can be applied to increase the accuracy of forecasts for hurricane intensity and climate prediction as well as to better use satellite observations in the numerical models.

"We provide evidence that observation of currents is important and has significant influence on models," Shi said.

Shi said she hopes to see the eventual launch of a satellite that observes ocean currents to validate ground observations.

Michigan Technological University

Related Atmosphere Articles:

Physics: An ultrafast glimpse of the photochemistry of the atmosphere
Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.
Using lasers to visualize molecular mysteries in our atmosphere
Molecular interactions between gases and liquids underpin much of our lives, but difficulties in measuring gas-liquid collisions have so far prevented the fundamental exploration of these processes.
The atmosphere of a new ultra hot Jupiter is analyzed
The combination of observations made with the CARMENES spectrograph on the 3.5m telescope at Calar Alto Observatory (Almería), and the HARPS-N spectrograph on the National Galileo Telescope (TNG) at the Roque de los Muchachos Observatory (Garafía, La Palma) has enabled a team from the Instituto de Astrofísica de Canarias (IAC) and from the University of La Laguna (ULL) to reveal new details about this extrasolar planet, which has a surface temperature of around 2000 K.
An exoplanet loses its atmosphere in the form of a tail
A new study, led by scientists from the Instituto de Astrofísica de Canarias (IAC), reveals that the giant exoplanet WASP-69b carries a comet-like tail made up of helium particles escaping from its gravitational field propelled by the ultraviolet radiation of its star.
Iron and titanium in the atmosphere of an exoplanet
Exoplanets can orbit close to their host star. When the host star is much hotter than our sun, then the exoplanet becomes as hot as a star.
Astronomers find exoplanet atmosphere free of clouds
Scientists have detected an exoplanet atmosphere that is free of clouds, marking a pivotal breakthrough in the quest for greater understanding of the planets beyond our solar system.
Helium detected in exoplanet atmosphere for the first time
Astronomers have detected helium in the atmosphere of a planet that orbits a star far beyond our solar system for the very first time.
Mountain erosion may add CO2 to the atmosphere
Scientists have long known that steep mountain ranges can draw carbon dioxide (CO2) out of the atmosphere -- as erosion exposes new rock, it also starts a chemical reaction between minerals on hill slopes and CO2 in the air, 'weathering' the rock and using CO2 to produce carbonate minerals like calcite.
The changing chemistry of the Amazonian atmosphere
Researchers have been debating whether nitrogen oxides (NOx) can affect levels of OH radicals in a pristine atmosphere but quantifying that relationship has been difficult.
Hubble observes exoplanet atmosphere in more detail than ever before
An international team of scientists has used the NASA/ESA Hubble Space Telescope to study the atmosphere of the hot exoplanet WASP-39b.
More Atmosphere News and Atmosphere Current Events

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

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.