Geog 1900: Extreme Weather and Climate

Review of last lecture• Atmosphere: A mixture of gas molecules,

microscopically small particles of solid and liquid, and falling precipitation

• Meteorology: The study of the atmosphere and the processes that form weather

• Weather: The state of the atmosphere at a given time and place

• Climate: The statistical properties of the atmosphere. (i.e. averages and variability)

• Weather- and climate-related disasters: tropical cyclones, tornados, floods, droughts, winter storms, extreme heat, extreme cold, lightning, El Nino, global warming

• Impacts of weather/climate on public health, transportation, agriculture, business, international relationships, history, science, philosophy, education, …

Atmospheric Sciences at a Glance (2)

The modern climatology (meteorology) was born in the 1940s (a very young science!), but has been

growing very fast!

Carl-Gustaf Rossby (1898-1957) Generally considered as the “father of modern meteorology”. Founder of the “Chicago School of Meteorology”.

Observing the atmosphere: Surface weather stations

1875 (~100)

1975 (>1700)

Observing the atmosphere: Surface weather stations

Now

Observing the atmosphere: Upper-air sounding stations

Now (>1000)

Observing the atmosphere: Weather Radar

First weather radar (NOAA NSSL)

Current NEXRAD Doppler radar (NOAA NWS)

Observing the atmosphere: Shipborne radar

From Mapes and Lin (2005)

Observing the atmosphere: Aircraft

NOAA P3

Video clip: Flying into hurricanes

• http://www.youtube.com/watch?v=hAyfHqEW3gk

TIROS-1 (1960) World’s first weather satellite

Observing the atmosphere: Satellite

NASA’s Earth Observation System

A-Train Satellites

Observing the atmosphere: Satellite

Observing the atmosphere: Proxy data(e.g. coral reef, tree ring, lake sediment, ice

core)

Coral reef Tree ring

Lake sediment Ice core

Climate Modeling on World’s Fastest Supercomputers

Japan’s Earth Simulator (World’s #1 in 2004, #20 now)

OSC’s new IBM machine among world’s top 100

World’s Major Global Climate Models

The current status of weather and climate predictions

• Weather prediction: Generally good within one week, not good beyond 10 days. The skill depends on season and location.

• Tropical cyclone (hurricane, typhoon) prediction: good in track, but bad in intensity

• Climate prediction: Seasonal prediction generally good within 6 months, but not good beyond. Skill depends on season.

• Climate projection: All models project global warming in the 21st century, but with a 3-fold difference in magnitude.

Why is it so difficult to understand and predict weather

and climate?

Summary• The modern climatology (meteorology) was born

in the 1940s (a very young science!), but has been growing very fast! Now we have a global observational network with many satellites, ships, radars and surface stations, as well as very comprehensive prediction models running on the world’s fastest supercomputers.

• The current status of weather and climate predictions: (1) weather prediction good to 10 days, (2) tropical cyclone prediction good in track but not in intensity, (3) climate prediction good to two seasons, (4) climate change projections have a 3-fold difference in magnitude.