Because of Earth's dynamic climate, winds and atmospheric pressure systems experience constant change. These fluctuations may affect how our planet rotates on its axis, according to NASA-funded research that used wind and satellite data.
NASA's Earth Science Enterprise (ESE) mission is to understand the Earth system and its response to natural and human-induced changes for better prediction of climate, weather and natural hazards, such as atmospheric changes or El Niņo events that may have contributed to the affect on Earth's rotation.
From year to year, winds and air pressure patterns change, causing different forces to act on the solid Earth. During El Niņo years, for example, the rotation of the Earth may slow ever so slightly because of stronger winds, increasing the length of a day by a fraction of a millisecond (thousandth of a second).
"The key is that the sum of the angular momentum (push) of the solid Earth plus atmosphere system must stay constant unless an outside force (torque) is applied," said David A. Salstein, an atmospheric scientist, who led a recent study. "So if the atmosphere speeds up (stronger westerly winds) then the solid Earth must slow down (length-of-day increases). Also if more atmosphere moves to a lower latitude (further from the axis of rotation), and atmospheric pressure increases, it also gains angular momentum and the Earth would slow down as well."
The fact that the two vastly different systems, namely the meteorological and the astronomical, are in good agreement according to the conservation of angular momentum gives us assurance that both these types of measurements must be accurate. It shows, moreover, that changes in climate signals can have global implications on Earth's overall rotation. >from *Changes in the Earth's rotation are in the wind*. march 5, 2003
related context
> global warming: u.s. climate action report 2002. june 12, 2002
> space weather - earth connection. june 6, 2000
> holes in sun's corona linked to atmospheric temperature changes on earth. march 19, 2000
> earth climate responds to variations of the sun's magnetic activity. june 16, 1999
> solar wind squeezes some of earth's atmosphere into space. december 8, 1998
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> earth flyball governor
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