Real Science or Reel Science?

Presented by:

Lis CohenMeteorology Graduate Student

National Science Foundation WEST FellowUniversity of Utah

Outline

• Can New York City go from hot to freezing in a few hours? Does climate change happen that fast?

• Is it true that the North Atlantic current could shut down?

• Is it realistic that a giant wave could hit New York City because of a hurricane?

• If air from the upper atmosphere is brought down to the surface in a hurricane, will it freeze us?

• Can big storms create giant tornados in LA?

Can New York City go from hot to freezing in a few hours? Does

climate change happen that fast?

• Climate change does not happen that fast or dramatically! – Ocean temperature changes take a

long time• Large heat capacity• Large ocean volume

– Ocean currents could change over many years

Is it true that the North Atlantic current could shut down?

The ocean surface transfers heat to the atmosphere!

Animation by Jack Cook (Woods Hole Oceanographic Institute)

What process could change the ocean circulation?

Can giant hurricanes exist all around the world?

• Clusters of thunderstorms cannot merge together to form a continent-scale blizzard with a calm eye over land.

• Huge storms with calm eyes happen over the oceans not over land. – Hurricanes or Tropical Storms

• Require that the core of the storm be over warm ocean water

Photo: earthobservatory.nasa.gov/NaturalHazards/Arch...

If air from the upper atmosphere is brought down to the surface in a hurricane, will it freeze us?

• Closer to the Earth’s surface, the air pressure is higher than higher up in the atmosphere. As we bring the air down to the Earth the air pressure increases. As we apply pressure to air, air warms instantaneously!

Bring air which is -80º C from 15km (tropopause) down to the surface

1. Temperature change because of pressure changes15km*9.8º/km(for dry air)= +147ºC

– Original temp + temp change = temp at surface-80ºC+147ºC=67ºC

– Change to Fahrenheit67ºC*(9/5)+32=152.6ºF

Can ice sheets melt and build overnight?

– Ice Sheets and Glaciers• Immense mass prevents rapid

melting of ice sheets.– Ex. Climate quickly changed at the

end of last ice age» Decades and centuries later

the ice sheets and deep ocean adjusted. (NSIDC)

• The major ice sheets over North America at the peak of the last ice age took tens of thousands of years to build up. (NASA)

http://daily.greencine.com/archives/day-after-tomorrow.jpg

Is it realistic that a giant wave could hit New York City because of a hurricane?

http://www.movie-vault.com/images/news/rainyorkbig.jpg

http://i.a.cnn.net/cnn/2004/SHOWBIZ/Movies/05/27/day.tomorrow/story.day.tomorrow.jpg

Tsunami vs. Storm Surge

TSUNAMI• Arrives quickly as a large wave

or movement of water onto the shore

• Causes– Earthquakes– Submarine Landslide– Calving of glaciers

• Tend to be localized events

• Antarctic ice collapse would not likely reach the US.

STORM SURGE• Arrives as a rise in water in a

period of a few hours.• Causes

– Low pressure of a storm lifts up the surface of the ocean (only a few feet)

– Winds pushing water onto the land

• Wind speeds would need to be at least twice the speed of sound (1200 mph) to create a 300ft storm surge.

Data from: Dr. Jeffrey M. Masters

Can big storms create giant tornados in LA?

Ingredients for a tornado:• Unstable Atmosphere• Moisture• Vertical wind sheerLos Angeles• Stable atmosphere• Little moisture

What process could most likely change the climate?

Warmer climate More evaporation at the equator

More moisture in the air

More moisture can be held in the air

More rain at higher latitudesMore freshwater

in the ocean

Ocean is not as salty and dense

Water does not sink in the northern latitudes

Circulation slows down

and changes

Melting Glaciers

Conclusion

• Climate change can not happen as quickly as the movie portrays.

• Scientists’ prediction models show a possible slow down and/or adjustment to the North Atlantic current, but not a shut down.

• Tsunamis not hurricanes, create waves like in the movie.

• If air from the upper atmosphere is brought down to the surface, we will have warm temperatures.

• Giant tornados in Los Angeles are very unlikely.

Questions?

How fast can the atmosphere and ocean respond to each other?

• El Nino-– Winds weaken and

ocean responds • This change can

happen on the time scale of weeks.

• Atmosphere– Readjusts within days

ex. Moving jet streams

How does ocean circulation affect local climates?

Intergovernmental Panel on Climate Change (IPCC), "Climate Change 2001: The Scientific Basis"

Warm surface current- Less Dense Cold deep water current–More DenseSalty water anywhere- More Dense

Answer: Heat release locations are warmer!

What directions do warm and cold water currents travel?

Animation by Jack Cook (Woods Hole Oceanographic Institute)

What is happening with ice shelves today?

• Today shifting climate – Antarctic Peninsula

the ice shelves are no longer stable. The northern most limit for ice shelves has moved south over the past two decades by about 100 miles. (NSIDC)

http://images.amazon.com/images/P/B0007PALRU.01.LZZZZZZZ.jpg

Three Glaciers Retreating

• Source: C.L. Andrews. 1912, 1938. Denver Glacier: From the Glacier Photograph Collection . Boulder, CO: National Snow and Ice Data Center. Digital Media; Marion T. Millett. 1958. Denver Glacier: From the Glacier Photograph Collection . Boulder, CO: National Snow and Ice Data Center. Digital Media.

Denver Glacier in Recession, Alaska, British Columbia

             

         1912

             

         1938

             

         

How do we know about past climates?

• Photo by: Lonnie Thompson, Ohio State University

• Ice sheets reveal annual layers– history of precipitation

and air temperatures 100,000 years in the past.

Flash Freezing• The superstorm sucks vast quantities of frigid upper atmospheric air

down to the surface, flash freezing any living thing caught outside. However, any graduate of a high school physics course could tell you that the air would warm on its descent in response to the requirements of the Ideal Gas Law, and would never be able to flash freeze anything. One scientist in the movie does remember his high school physics and asks, "But wouldn't the air warm as it descends?" But the senior scientist replies, "No, it's moving too fast!" Sorry, guy, but the Ideal Gas Law applies no matter how fast the air is moving. If you were on my thesis committee, I'd kick you off.

• by Dr. Jeffrey M. MastersChief Meteorologist, The Weather Underground, Inc.

Storms flowing opposite directions

• The superstorm is shown in many scenes rotating clockwise, and in other scenes counter-clockwise. Oops, all large-scale storm systems in the Northern Hemisphere must rotate counter-clockwise, thanks to one of the laws of physics on a rotating planet called the Coriolis force. – by Dr. Jeffrey M. Masters

Chief Meteorologist, The Weather Underground, Inc.

In a warmer earth scenario

– Ocean level will rise because as liquid water is heated it expands.

– The ice caps melt and add water to the system.

• http://www.whoi.edu/institutes/occi/images/occi_abrclimate_jk_lev_en.gif

Temperature and Ice Accumulation vs. Time