Native Plants, Habitat Restoration, and Other Science Snippets from Athens, Georgia

Saturday: 26 January 2013

Winter Biological Activity  -  @ 10:19:11
We do have some spiders that survive well into the winter. We have some small wolf spiders that scamper through the leaves even on cold days, but these active ones are mostly the exception.

It took awhile to identify this large one as a marbled orb weaver, Araneus marmoreus, also called pumpkin spider. It was paddling down SBS Creek on a little raft on Jan 9. This was just at the beginning of our six day hot spell with temperatures 20-30 degF warmer than usual.

I actually found another in Dec 2005, nearly identical to this one. And then again in Oct 2007.

Here's a better view of the eyes.

I'm not the only one who finds these in winter. Here is a a North Carolina report to Bugguide in January.

You'll notice the abdomen doesn't look so much like our spider's. There is a lot of polymorphism to this species, as you can see by the Bugguide images page.

The eyes, though, match up nicely to the North Carolina report.

Saturday: 19 January 2013

Fall and Rise  -  @ 13:53:31
Do visit our old friend Mark P's new website, Caniconfidimus. I was delighted that he decided to do this. He's been a commenter on many, many websites, with clever comments and observations that really needed a venue of their own. Mark has already addressed our [north Georgia] last few days of wintry weather here, and that includes a photo of a moderately swollen creek much more magnificent than my own, which I will address shortly. Mark also has cats, which aren't his particular sorts of animals. Nonetheless he features them prominently, perhaps because of his eminently sensible wife. Anyway, go there.

And so, back to topic:

We're back to a kind of average January weather pattern. For a week our highs were in the 70s, which is 20-25 degF above normal highs. The nighttime temperatures were in the 50s, similarly above normal. This was much like March of last year, a high pressure pattern over the eastern US states that brought temperatures into the 80s, again 20 degF above normal for March.

And then, we had three major days of rain, beginning Tuesday, and on Thursday the temperatures fell back to normal. If the timing had been right we would have had snow or ice, but as it was it stopped raining long enough before the cold so that we had nothing.

I've done it before, but let's do it again: Here are some Goulding Creek comparisons, before and after the 2.6 inch rain.

This is part of my daily walk, which usually amounts to two miles. On this occasion, on Sunday before the rain, Glenn also braved the wilds and even got into the creek. We've had quite a rain deficit, so most places just had a few inches of water flow. I love this picture because I never have a really good scale - Glenn provides it here. Goulding Creek isn't really that pathetic, is it? No, it's a typically idyllic small southern flow toward the sea.

Although this isn't exactly the same section, it's good enough to show the effect of the rain on Goulding Creek just after it stopped, on Thursday. You'll notice it was fairly muddy - an indication that we're having some runoff into the creek itself, and the feeder creeks as well.

I love Goulding Creek. I'd love it by now no matter what, just as I love the little feeder creek that runs through our property and into Goulding Creek. Goulding Creek is a homely, modest little creek but it's significant enough to have a name two centuries old*. I suspect it's been plowing its way through our backwoods for, well, probably thousands of years in one form or another. I love walking down it, and seeing it in its different phases. Sometimes it's just a trickle, and that alerts me to the extremity of our weather. And then it swells to enormous proportions, as we've seen here. Over the years and many miles and hours I've walked down it, I've only seen one other person enjoying the creekside hike. Isn't that interesting?

We're back east, 1/3 mile upstream at the roadcut, what used to be the westernmost boundary of our property in the 1990s. Here's what it looked like on Thursday afternoon, just after the rain stopped. As it was above, it's muddy here too. This point in the creek has been one of the most interesting to watch, and I've referred it many times, including from just about this point in the link above.

Let's do revisit what that very section looked like after that real rain in March 2007. It's next to a photo taken a day or so earlier, before the rain, and what it usually looks like. I guess you can see that Thursday's rain effects are nothing like the ones in March 2007.

And finally, here's Goulding Creek at that same location yesterday. The level has gone down somewhat, although still higher than it has been in the last year or so. The water has cleared up too, and that's one of the nicest things about Goulding Creek. When it's been flushed of its bottom debris and has settled down after a rain, it's clear, with a sandy or rocky bottom.

A good bit of this was addressed at our annual CoCoRaHS meeting for the Oglethorpe County rainfall measuring network. Our Georgia Regional Coordinator, Pam Knox, answered the question about rain and lack of creek recovery: even though we had December rain, it wasn't enough to replenish soil moisture, therefore none of it ended up enhancing the flow in the creeks and rivers. It's been very very dry around here.

I think, though, that we might have finally replenished the soil, and that this past rainfall actually began to run off into the creeks for the first time in many months.

*Goulding Creek, perhaps named after Daniel Goulding or Golding, 1790s, Militia District 227, Captain. I'd love to know where he lived for the creek to be named after him.

Sunday: 6 January 2013

Back in Season  -  @ 10:20:16
January 1 was the last day of deer hunting season, and that means our 20 acres to the west is now available for our use. (Folks will recall that we let the hunting club use that part of the property from mid September through, well, Tuesday.)

So I've been enjoying the walks which cover some steep hills and visit two "decks" or bluffs. All of this can easily take up two miles of walking. Mostly though, I now can walk down (or up, as in this case) Goulding Creek. Since we've had a surplus of rain in the last month, the creek looks pretty good. We'll have to have a lot of rain over several days to actually get a good torrent down the creek. This last month has just restored it to some resemblance of normalcy.

I noted what looked like a fresh treefall over the access road to the first deck. It's a medium size dead loblolly pine of the sort that falls everywhere around here. No surprises. This must have happened in the last week because otherwise it would have been quickly removed by the hunting club manager.

No problem for us - the access road is not mostly owned nor ever used by us. The property line runs over the last couple hundred feet of it, but the vast length that we do not own (including this tree) begins at a gated and locked entrance on Wolfskin Road, pretty close to our fire station, actually.

Besides just getting a chance to enjoy the extra walking distance, it's also nice to see that the hunting club members left things just as they found them. For the third year in a row, no trash, access roads with little or no traffic damage, not even at the decks where there is a just barely visible impromptu cul de sac. That's how we were hoping things would be treated, and that's how it continues to work out.

( This post from early March last year maps out the area I'm talking about, the "decks," and the routes I typically take. There are also some other nice photos.)

Saturday: 5 January 2013

Two Thousand Twelve  -  @ 07:52:57
It's time to remember the weather in 2012. Hopefully NOAA will have its annual summary up soon.

Below (and clickably linked to a larger version on a new page) is my usual summary figure for the year. What started out as a purple curve are the mean daily temperatures over 30 years, so that's our temperature baseline. The blue and red dots are individual temperature measurements during 2012 and 2011, respectively. The thick blue and red lines are 25-point running averages to smooth things out a bit.

At the bottom of the figure are individual daily precipitation measurements for 2012 (the dark green bars), and the light green line shows accumulated precipitation for the year. That's to be compared to the 30-year average accumulation shown by the dotted green line.

Here are the main features for 2012:

A-C are unusual temperature regimes.

A: We had a long period of extremely warm March temperatures - unprecedented here and affecting much of eastern North America. Remember? This was the result of a long-term high pressure system centered over the mid west.

B: A similar system caused unusually high temperatures just about everywhere in the first half of December. Hardly anyone around here noticed.

C: High temperature records were set just about everywhere toward the end of June and into July. We hit 109 degF on June 29. That was the all time record high for any day in Athens, until two days later on July 1. That was also the day we were called to a large structure fire off US 78.

D-F are unusual precipitation patterns.

F: Our total for the year was about 36 inches rain, 75% of the normal 48 inches. 2012 would mark the 8th or 9th lowest rainfall since 1920, from Athens records. Taken as pairs of years, though, 2011 (also 75% rainfall) and 2012 would be the third driest pair since 1920.

D, E: Not many people noticed the dry year. I think this is why: We had two long periods with little rain, but these periods were during the months of March-May (D) and October - November (E), when temperatures were relatively mild. We actually had a fair amount of rain during the (for the most part) not-so-hot summer.

This wasn't a very hard year to summarize. Others elsewhere had more extreme temperature and precipitation conditions, and of course much more intense storms, than we did.

Below is a much simpler plot of our temperatures, with a 100-point running average so you can see the long periods of high temperatures. Again red is 2011 and blue is 2012. Isn't it interesting how temperatures in both years settled down during the autumn before beginning fluctuations in the late autumn and winter?

Wednesday: 2 January 2013

The Month of December  -  @ 08:47:56

It's The Month of December, Number 83 in a series. That also means it's 2013, so Happy New Year!

Here are the usual temperature anomalies products, at the National Weather Service Climate Prediction Center.

As in November, much of the western US showed anomalously high temperatures. In December, though, nearly the entire country had anomalously high temperatures. Temperatures were 6-8 degF higher than normal in IL, IN and much of OH and TN. They were just slightly lower in the rest of the eastern US. This was particularly true during the first 2-3 weeks of December.

We find the National Weather Service Climate Prediction Center's precipitation plots here.

There was some relief from November's near total dry conditions, in December. Much of the eastern and western US received normal to above normal rainfall. However that left the already drought-stricken southern states centered around Texas again abnormally dry.

For the Athens, GA area:

Here is a plot of our daily temperatures excursions in December, along with precipitation amounts as experienced in Wolfskin. Temperatures declined in steps, much as they did in October and November:

The average monthly temperature for December was 49.8 degF, more than 4 degrees above normal. We had 8 days more than 1 standard deviation above normal highs (5.6 normal), and 2 days more than 1 standard deviation below normal lows (4.3 normal). Definitely skewed high in December. In fact, with November's temperatures lower than normal, the average mean and lows for December were 2-4 degF higher than November's, one of those weird month reversals that happens now and then.

The monthly histogram below shows the breakdown of high and low temperature range counts from December 1948 on. Most temperature ranges individually just barely showed significance (check out the error bars set at plus one standard deviation).So we had 5 days above 70, but average is 2 +/- 3 so by itself, not impressive. We had more daytime temperatures smack in the middle range, 50-59 degF, but that again is just barely covered by the error bar. However, it's clear that there is a trend - the number of days average to warmer clearly come from the days in the cooler ranges <50. Similarly for the nighttime lows.

The figure below shows the Athens precipitation data which are official for our area. As usual the green line shows our actual rainfall, the red shows the average accumulation expected. The black dots are rainfall over the last 20 years, the vast river of peach shows the standard deviation, and that rare blue color at the end shows we got a 1 SD surplus of rain for December.

Our total out here was 6.20", and in Athens (shown here) it was 5.86". 3.73" is normal for December, so we were well above normal. Most of the rain fell after that first two weeks in December.

I have a feeling that places farther north really noticed the warmer December temperatures. Here, not so much. It may get cold here in December, and we'll notice unusually cold temperatures. If it's on the warmer side of average though, most people here won't notice that.

Prognosticator stuff:

What is the neat prognosticator telling us? These much warmer temperatures look to persist over the next month for the eastern US. For northeast Georgia, it looks like warmer than normal temperatures for the next three months. This bodes ill for snow. Precipitation is predicted to be above normal in January and February, and then equal chance of above/below normal in March.

ENSO stuff:

The folks at CPC have a version of PDF or HTML that is much different from their previous presentations, but at least it's there and the link isn't broken.

As of Dec 31, ENSO neutral conditions continue. It continues to seem like no El Niño will develop this winter.

As of Dec 25, the US Drought Monitor continues to have us in extreme to exceptional drought, depending on where you are in Georgia. Much of the US continues to be under at least abnormally dry or moderate drought classification, with a lot of the country in severe or extreme drought. However the forecast for the southeast suggests at least some improvement, if not a reversal in the next three months.

NOAA's Monthly State of the Climate product for November is available, and includes discussion of the immediate aftermath of Hurricane Sandy. The summary for 2011 regionally, nationally, and globally is also available. Soon we'll have a discussion of the weather of 2012.

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