Extreme Lunar Perigee March 19, 2011 Means More Storms and Flooding
Tuesday, January 11, 2011 8:25
As you may know, tides peak twice a day in a given location as it moves past the line connecting the center of the moon and the earth. This is because that point on the earth's surface passes through the permanent tidal bulge that follows the moon's position. The magnitude of the tide (tidal bulge) is determined mainly by the distance to the moon and the sun and by the angular separation between the two of those. The daily tides peak at new and full moons when the earth, moon and sun line up (at a syzygy).
The gravitational forces of the moon maximize every month when it makes close approach to the earth (perigee). The gravitational forces of the sun maximize every year when the earth makes its close approach to the sun (perihelion). The bi-monthly tidal peaks which occur at the sun, moon, earth syzygy peak every seven months when either a new or full moon coincides with the lunar perigee. Since the period between perigees is shorter than the period between full moons, after coinciding with a syzygy, the perigee is two days out of synch more every month, until seven months later. So,
the tides peak alternately at new and full moons every seven months.
As you can imagine, these seven month peaks peak themselves when the earth is also closer to the sun. Theoretically, the highest tide would occur at a new moon at its perigee when the earth was at it perihelion the first week in January. Perigee-syzygy combinations that happen near the perihelion make for even closer perigees. The closest approaches of the moon to the earth 'recently' occurred at full moons on Jan 4, 1912, Jan 15, 1930 and Jan 26, 1948.
Here is a link to a webpage that allows you to generate the times of the new and full moons and the perigees and apogees (moon's far point from the earth) by entering the year and hitting 'calculate'.
www.fourmilab.ch/earthview/pacalc.html If you enter 1912 you will see Jan 4 13:34 356378 km ++ F+ 0h, which means that on Jan 4th that year, the perigee was O hours after the full moon, and the moon was 356378 KM from the earth then. That was the closest for a long time. If you enter 2011, you see an F + 0h for March 19th too. This time the moon will be 356577 km from the earth, which is the 6th closest approach for the moon between 1985 and 2012. 4, 7 and 6 are in 2008, 2010, and 2011. 1,3 and 2 were in 1990, 1992 and 1993.
If you look at 1993, you will see that the March 8th perigee marked F - 1h, meaning it happened just over an hour before the full moon then. If you do a search for the weather then, you will find that on March 12-13, 1993 a 'super storm' struck the eastern half of the US. "The coldest march reading in Birmingham, Alabama history was 2F on March 14, 1993. That was the day after the 1993 blizzard, which is also remarkable for producing the city’s biggest snowfall ever, 13 inches at the Airport."[
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