Tuesday, August 7, 2012

Before The Rain...

(The tidal creek that backs up our building...the tide is out, leaving the muddy bottom exposed)

It was about 4:30 PM. The 'Weatherscan Channel' was promising a higher than usual percent chance (60%) of rain. Looking out the window I could see that the sky was overcast. The light level was dim and moody. I decided to take advantage of the blocked sun-rays, and take some photos of the tidal creek and surrounding trees. I could hear the distant rumble of thunder. It didn't appear that we were going to get rained on at that particular moment, so I went for it.

(The moody sky)
Once I exited the back door, I knew we were going to get some rain. I didn't know how much, but we were going to get some. I could smell it.

(One of the moss covered trees just outside the screened-in porch)
I have had people look at me like I was nuts on more than one occasion when I have said that. Many people think of that statement as being a southern adage, and don't think it based on fact.  Well, guess what? From now on when you hear someone say, "it smells like rain", you can believe them.

(A few images of the one Dogwood Tree I have
seen in our vicinity)
There is a term for the scent: petrichor. It means 'the scent of rain falling on dry earth'. The word is derived from the Greek word petros ("stone"), and tichor (the fluid that flows through the veins of the Greek gods). The term was coined in 1964, by Aussie researchers, Thomas and Bear. They explained that an oil is exuded by some plants under dry conditions.  The oil is absorbed by clay soils and rocks. When it rains, the stored oil is released into the air, along with a compound emitted by wet soil. The second compound is called geosmin ("earth-smell").

Geosmin is produced by a combination of bacteria and algae. When soil is disturbed, in this case by rain, the compound is kicked up into the air. If a storm is approaching and geosmin molecules blow or waft by, that indicates that rain is falling windward.

In terms of the scent, it take an extremely small amount of geosmin for the human nose to pick up on it. For some reason, the human nose is extremely sensitive to geosmin. A lot of it can be unpleasant. So much so, that some find it repellent.

As far as it being toxic, geosmin seems to be harmless to most animals. No one seems to know why we are so sensitive to it, or what it's actual purpose is.

There you go. My interesting factoid of the day.

(The 'pet cemetery' I discovered in my first October in Savannah, several years ago...the bushes that used to obscure
the tiny grave markers are now gone...there used to be collar tags, and other remembrances of those faithful friends buried there, but unfortunately they are now gone)
It felt better outside than it has in awhile. Like many parts of the US, we have been having some really hot weather here in Savannah. Add the humidity (we get forecasts of potential rain everyday, but mostly in the area of 30% - which most times means 'no rain'). Tack on the absence of any comfort providing breezes. That's a recipe for misery. Staying inside in the air conditioning has been mandatory. But, not today.

I kept today's walk to the tidal creek bank. The breezes were wonderful, and added to the enjoyment factor. They kept the mosquitoes at bay.

The vibe of this past evening made me think of the approaching Fall, my favorite season. It will be here before we know it.

My short little excursion reminded me of how therapeutic even a few minutes out of doors here can be. It is clear that I need to ignore my knee pain, and get out for a stroll...even if it's only for ten or fifteen minutes. Stepping out into nature makes all the difference in a day...one of the best stress relievers there is.

I think that tomorrow I'll visit 'my' park here on the island. Always devoid of people, it's main inhabitants are a collection of huge old trees that create a chaotically twisted and lush canopy. It has been awhile since I visited there.

I'm looking forward to it...unless it rains...

1 comment:

  1. Interesting area,so different from mine. There has been much talk of rain(or lack of it)this summer!