GFDL - Geophysical Fluid Dynamics Laboratory

NOAA GFDL Climate Research Highlights Image Gallery
A Tropical Atmospheric Circulation Slow-Down

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2-D Graphics & Maps
  • GFDL scientist contacts for this topic:
    Gabriel Vecchi, NOAA/GFDL
    Isaac Held, NOAA/GFDL
  • GFDL Communications Officer: Maria Setzer, NOAA/GFDL
  • Graphics developed by Gabe Vecchi.

Contact information (email, phone numbers) can be found for these people by entering their names into the NOAA Staff Directory.

The materials presented here help illustrate some of the key research results that GFDL scientists have reported on recently. These graphics are considered to be in the public domain, and thus can be downloaded freely. We do request that if these images are used in publications or media broadcasts credit be given to “NOAA Geophysical Fluid Dynamics Laboratory” or at least “NOAA GFDL“.

2-D Graphics
[Walker Circulation global warming schematic]
ABOVE: 610 x 480 png [202KB]

Also available as:

Figure Caption:
A schematic view of the three-dimensional Walker Cell circulation. The Walker Cell circulation consists of trade winds blowing from east to west across the tropical Pacific Ocean (blue arrow), bringing moist surface air to the west. In the western tropical Pacific, the moist air rises, forming clouds. The rising air becomes drier as much of its moisture falls to the surface as rain. Winds a few miles high blow from west to east, moving the now drier air toward South America. The air descends back to the surface in the eastern tropical Pacific, dry and relatively cloud free, completing the circulation loop. Atmospheric sea level pressures are higher under the dry sinking air in the eastern Pacific than in the warmer and more humid west


[Walker Circulation and ocean schematic with text]

ABOVE: 600 x 240 png [76KB]Also available as:

Figure Caption: In a warmer climate, (A) evaporation from the warm tropical Pacific Ocean increases strongly and moistens the lower atmosphere. East to west surface trade winds (B) transport the warm moisture laden air to the the western Pacific (C), where the moist air rises and feeds rain, but the rainfall increases more slowly than the atmospheric moisture content. To compensate for the moisture imbalance, the trade winds (B) slow, as does the entire Walker Circulation loop, including the upper level winds (D).