rainfall exhibits strong variability on time scales shorter than the seasonal El Niño
Southern Oscillation. These fluctuations in tropical rainfall often go through an entire
cycle in 30-60 days, and are referred to as intraseasonal oscillations. (For more
information see Frequently Asked Questions)
The intraseasonal oscillations are a naturally occurring component of our coupled
ocean-atmosphere system. They significantly affect the atmospheric circulation throughout
the global Tropics and subtropics, and also strongly affect the wintertime jet stream and
atmospheric circulation features over the North Pacific and western North America.
As a result, they have an important impact on storminess and temperatures over the United States
During the summer these oscillations have a modulating effect on hurricane activity in
both the Pacific and Atlantic basins. Thus, it is very important to monitor and predict
intraseasonal activity, since this activity has profound implications for weather and
short-term climate variability through the year.
Key monitoring tools are: