LIVE INTERACTIVE LEARNING @ YOUR DESKTOP. NOAA/NSTA Web Seminar: The Ocean’s Role in Weather and Climate. http://institute.nsta.org/web_seminars.asp.
NOAA/NSTA Web Seminar:
The Ocean’s Role in Weather and Climate
The influence of the Atlantic ocean on climate, from Atlantic hurricanes to African droughtThomas L. DelworthGeophysical Fluid Dynamics Laboratory/NOAAPrinceton, NJ
at high latitudes
from “Earth's Climate Past and Future”, Ruddiman.
Question: The rate of heat (energy) transported by the Atlantic ocean is ~1.3 *1015 Watts. The amount of energy moved poleward by the Atlantic Ocean each year is the equivalent to approximately how many years of total U.S. electricity generation:
Temperature (Deg C)
Tropical North Atlantic
1996-2005 minus 1970-1990
Where did the largest warming take place?
have existed for centuries.
Gray et al., 2004, Geophysical Research Letters
How can we better understand (and predict) the impact of the North Atlantic ocean on climate?
Computer climate model is a “Virtual Earth”, in which we can perform many experiments to better understand the system.
In models, the earth’s land, ocean and atmosphere are chopped into 5 million grid cells.
Horizontal Grid (Latitude-Longitude)
Vertical Grid (Height or Pressure)
Climate models use world’s fastest supercomputers … but need
computers that are 1000 times faster (at least!).
New York, NY
100 mm/month is
about 50 inches per year
Data from Univ. of
(Atmosphere model forced with
observed SSTs 1950-2000)
Modeled AMO Index
Observed AMO Index
Observed rainfall changes
The rainy season in the Sahel region of Africa is:
Blue means more rainfall
when the North Atlantic
Simulated multidecadal JJAS surface air temperature difference (K) (1931-1960) – (1961-1990)
Reduction in Wind Shear when North Atlantic Warms relative to South Atlantic
Model (GFDL CM2.1)
Zhang and Delworth, 2006
Red means less shear, and therefore more favorable conditions for hurricanes.
CONCLUSION: Models demonstrate that a warming North Atlantic (relative to the South Atlantic) CAUSES atmospheric circulation changes that are favorable for tropical activity.
If all emissions of carbon dioxide were stopped tomorrow, how long would the ocean continue to warm?
You are here (now)
Modeled (GFDL CM2.1)
Role of aerosols
In late 20th century
Steady or slightly
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