Showing posts with label spring. Show all posts
Showing posts with label spring. Show all posts
Tuesday, 18 April 2017
Special Report What the heck is a perigean spring tide
(corrected text, because I was informed I didn't know what month it was! Thanks, Pat.)
They dropped this term on The Weather Channel this morning. Dang, we had to look that up! The moon has something to do with the tides, right? (Go ahead. Look it up. I'll wait.) During the full moon (twice a month), the tidal range is greater (or high tide is higher and low tide is lower)--that's called spring tide.
They dropped this term on The Weather Channel this morning. Dang, we had to look that up! The moon has something to do with the tides, right? (Go ahead. Look it up. I'll wait.) During the full moon (twice a month), the tidal range is greater (or high tide is higher and low tide is lower)--that's called spring tide.
When the moon is closest to the earth, it is called a lunar perigee. The gravitational pull of the moon is the strongest.
Three to four times a year, the lunar perigee and full moon coincide. This is the perigean spring tide (or unofficially, the supermoon or "king tide" in New Zealand) and can affect tides up to 20 percent (usually just a few inches). Apparently, we experienced this once in Annapolis--when it's perigean spring tide, wind blows onshore from the bay and it storms (barometric pressure drop), they get flooding downtown.
If you're still reading this, the next perigean spring tide in August 29th (this Sat), and it coincides with the possible arrival of Hurricane Erika on the Atlantic coast. Yikes. The Weather Channel specifically mentioned Charleston.
Here's more info:
NOAA perigean-spring-tide
http://earthsky.org/space/what-is-a-supermoon#how-many
Woods Hole Oceanographic: Perigean Spring Tides Aug 1998
Don't get me started on neap tides and apogees.
Saturday, 8 April 2017
Do Ducks Get Spring Fever
There are seven herons on the south side of #1 island today and two more on the opposite point. It's not the congregation that I saw last year, but still, it is a denseness of herons (I take no photos because they have some purpose that I feel I should not upset). I've never been one to personify animals, believing that we should keep people as people and wildlife as wildlife, but something in my right brain, in my creative side, tells me that herons are the elders.
Not necessarily my elders, but elders none the less. They seem, through their calm behavior, their steady movements and their graceful flight to be the reincarnations of people who were, when they walked this earth, at harmony with nature. These elders that take the heron form aren't the generals, warriors or titans of industry. I don't know where they are. These are the gentlefolk, the ones who got solutions through gentle persuasion. These were the people who made everyone else calm down just by their presence... although some little fish may disagree.As I paddle south across the bay, ducks everywhere I moving about. This usually signals the arrival of an eagle, but I see no eagle and the ducks ALL over the bay are in motion. It is something to see, if one is paying close attention. A soft roar of a thousand wings on water finally signals the arrival of an eagle, but it is just passing by. The ducks just keep flying and swimming about. Perhaps, ducks get spring fever.
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