Moon Affects Rainfall on Earth, too, Not Just Tides

A new study suggests that the gravity of the moon affects rainfall on Earth, too, not just tides as we have been taught in school. A group of researchers at the University of Washington found that the Moon’s position over different parts of the Earth has a slight influence on the amount of water that reaches the surface.

Researchers explained that the Earth’s natural satellite can generate bulges in the upper layers of the planet’s atmosphere. These bulges affect the amount of rainfall, thought the effect is nearly imperceptible.

Tsubasa Kohyama, lead author of the study, said that the new research was the first to find a link between the Moon’s gravitation and amount on rainfall down hear on Earth.

Prior to this study, the research team had conducted another study on the variations in air pressure and the role the Moon may play in these changes. Researchers found that when the moon is high in the sky or underfoot air pressure rises.

The recent study has confirmed that these variations in air pressure may affect rainfall. Scientists found that when the Moon is up in the sky, its tidal force forces the planet’s atmosphere to slightly bulge in Earth’s direction. As a result, on that side of the planet the air pressure becomes slightly higher.

But while air pressure rises, so does the temperature within atmospheric layers below. The team explained that higher temperatures mean that the air can retain more moisture. Kohyama likened the phenomenon to a container whose size suddenly becomes larger and can retain more liquid.

Level of moisture just above ground level has a strong influence on rainfall, because a lower amount of moisture means less precipitation.

Scientists based their recent findings on data provided by NASA and Japanese space agency’s Tropical Rainfall Measuring Mission satellite. The data, which was collected over a 15-year period, showed that when the Moon is at its peak, rainfall on Earth is slightly less abundant.

The team argued that the slight variation does not have a major impact on weather or people because the Moon affects just 1 percent of rainfall changes. Also, people will not notice any difference without special measuring instruments.

Study authors believe that the new findings could also be used to confirm current climate models to see how exactly the Moon’s tidal force reduces the amount of rain that reaches surface.

A research paper detailing the study results was recently published in Geophysical Research Letters.

Image Source: Wikimediar