You probably already know that the Moon’s position has a direct impact on the Earth’s tides. However, newly published research reveals that the Moon also has a say in the amount of rainfall the Earth experiences.
— Am Geophysical Union (@theAGU) February 1, 2016
According to NPR, scientists at the University of Washington have determined that when the moon is high, there’s less rainfall. The study was co-authored by researchers Tsubasa Kohyama and John Wallace. The groundwork for this discovery was laid when, as detailed by Phys.org, Kohyama first noticed a “slight oscillation in the air pressure” while studying astronomic waves.
It turns out that linking air pressure changes to the Moon isn’t all that new. The impact of phases of the Moon on air pressure was first written about in 1847. Making the connection with rainfall? Kohyama proudly touts that the study as the first of its kind.
“As far as I know, this is the first study to convincingly connect the tidal force of the moon with rainfall.”
But what does the moon’s position have to do with rainfall?
“When the moon is overhead, its gravity causes Earth’s atmosphere to bulge toward it, so the pressure or weight of the atmosphere on that side of the planet goes up.”
In other words, when the Moon is high, it raises the atmosphere’s pressure in a way that causes a noticeable decrease in rainfall in the impacted area.
— Climate Realists (@ClimateRealists) February 1, 2016
The outcome of this unique study didn’t come about overnight; Tsubasa and John reportedly spent two years “tracking down the phenomenon.” This included carefully examining data compiled by “NASA and the Japan Aerospace Exploration Agency’s Tropical Rainfall Measuring Mission satellite” over a period of 15 years. The results of the study were published on Saturday in Geophysical Research Letters.
Before you start using the Moon’s position to determine whether to bring an umbrella with you, there’s something else you should know about Kohyama and Wallace’s research. Ultimately, although the Moon’s phases do have a say in the total rainfall on Earth, it’s a rather tiny say.
The study results indicate that the Moon affects “only about 1 percent of the total rainfall variation.” Definitely not enough to plan your day by.
— 89.3 KPCC (@KPCC) February 2, 2016
With this in mind, it’s important to note the study’s co-authors have far more practical aspirations in mind when it comes to how their research is applied. Kohyama hopes other scientists can use the research “to check if their physics is good enough to reproduce how the pull of the moon eventually leads to less rain.”
Meanwhile, study co-author John Wallace has plans to “continue exploring the topic.” For example, he hopes to determine if heavier downpours might be directly impacted by the Moon’s position. John is also interested in determining if the frequency of rainfall has a lunar connection.
Given the fact that few people would have previously expected any true correlation between a high moon and lower rainfall, it’s entirely possible this additional research may produce surprising news.
— Smithsonian Magazine (@SmithsonianMag) February 1, 2016
As previously stated, the moon’s impact on the tides is well-known, but did you know that the Sun also has an influence on the Earth’s tides? However, the distance between the Earth and Sun means that our star isn’t having nearly as much of an effect as the much, much closer Moon.
Another fascinating tidbit about the moon? Despite the popular misconception, it’s not the Moon’s gravity that causes tides. Instead, tides are caused by a “tug of war” between the Earth’s gravity and the Moon, with the Moon having enough of a slight advantage to produce tides.
Any Moon-related facts to share? What do you think of the rainfall study? Please comment below!
[Photo by David Ake/AP]