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

Friday: 30 November 2007

Decay Time  -  @ 07:57:31
I'm sure everyone has been wondering what has happened with the northern red oak that fell a coupla years ago. It initially appeared here, and then more analytically here. It's provided fodder for posts and now for fungi.

The branches in the background are well beyond rotting now, and dropping off to the ground, but the trunk continues to evolve in its decay, and has remained sturdy, as it probably will for many years. This is the first time I've seen opportunistic growth of mosses, although they've probably been present in less obvious numbers for some time, maybe from the very beginning.

Lots of questions, few answers, mostly due to my lack of familiarity beyond matching pictures. With the little bounty of rain and cooler temperatures has come the emergence of green, growing mostly within the furrows and highlighted by contrast with the northern red oak white ridges.

Contributing to the green are mosses and lichens. The gray lichens are very attractive, and there are at least two other "species" here. The white may be a different species, or it may be a sporulating portion of the leftmost green patch, or it may be a hyperparasitization by some other fungus:

There are at least four species of shelf fungi (that's not a taxonomic term) appearing in large numbers. This one may be a polypore, but I don't find anything resembling it.

Rows and rows of this gilled species have appeared. At first I thought they might be oyster mushrooms.

The scaly caps suggest they are not, but still I keep getting back to the Tricholoma Family. A Lentinus is not out of the question, though I didn't check for stems. They may also be a luminescent Panellus, so I should probably bring some up to a dark room to check. It's not likely - most of the luminescent Panellus I see are much smaller and growing from twigs.

These likely Polypores have a nice appearance. Closest I can come here by matching pictures is a Mustard-Yellow Polypore. The top coloration and patterns works fairly well.

From beneath are these lovely patches of what are probably the polypore tubes from spores will emerge.

A pretty network of tubes!

Thursday: 29 November 2007

Anthropogenic Biomes  -  @ 09:00:29

UPDATE Dec 2 2007: I have taken a second look at the work addressed by this somewhat regretted post, following a reading of the paper itself kindly sent by the authors Erle Ellis and Navin Ramankutty. You can find that second look, along with a response by the authors, here.

If you took an organismal biology course, you probably had to wade through the 30 biomes with their mind-numbing characteristics. Of course when you really look at them, in depth, one by one they're fascinating, but textbook presentation is usually pretty lacking in a survey course. Apparently the focus by ecologists on biomes as pristine environments is also out of date.

Eurekalert, which I scan through every coupla days, offered me this today. I don't know how long that latter popup is stable or viewable, so here's the summary in its entirety:
Environmental researchers propose radical 'human-centric' map of the world
Humanity has greater impact on global environment than 'natural' forces, they say

This release is also available in French.

Ecologists pay too much attention to increasingly rare "pristine" ecosystems while ignoring the overwhelming influence of humans on the environment, say researchers from McGill University and the University of Maryland, Baltimore County (UMBC).

Prof. Erle Ellis of UMBC and Prof. Navin Ramankutty of McGill assert that the current system of classifying ecosystems into biomes (or "ecological communities") like tropical rainforests, grasslands and deserts may be misleading. Instead, they propose an entirely new model of human-centered "anthropegenic" biomes in the November 19 issue of the journal Frontiers in Ecology and the Environment.

"Ecologists go to remote parts of the planet to study pristine ecosystems, but no one studies it in their back yard," said Ramankutty, assistant professor in McGill's Department of Geography and the Earth System Science Program. "It's time to start putting instrumentation in our back yards – both literal and metaphorical – to study what's going on there in terms of ecosystem functioning."

Existing biome classification systems are based on natural-world factors such as plant structures, leaf types, plant spacing and climate. The Bailey System, developed in the 1970's, divides North America into four climate-based biomes: polar, humid temperate, dry and humid tropical. The World Wildlife Fund (WWF) ecological land classification system identifies 14 major biomes, including tundra, boreal forests, temperate coniferous forests and deserts and xeric shrublands. For their part, Ellis and Ramankutty propose a radically new system of anthropogenic biomes – dubbed "anthromes" – which includes residential rangelands, dense settlements, villages and croplands.

"Over the last million years, we have had glacial-interglacial cycles, with enormous changes in climate and massive shifts in ecosystems," said Ramankutty. "The human influence on the planet today is almost on the same scale. Nearly 30 to 40% of the world's land surface today is used just for growing food and grazing animals to serve the human population."

The researchers argue human land-use practices have fundamentally altered the planet. "Our analysis was quite surprising," said Ramankutty. "Only about 20% of the world's ice-free land-surface is pristine. The rest has some kind of anthropogenic influence, so if you're studying a pristine landscape, you're really only studying about 20% of the world."

"If you want to think about going into a sustainable future and restoring ecosystems, we have to accept that humans are here to stay. Humans are part of the package, and any restoration has to include human activities in it."

Also embedded in the above summary is this link to a ten-minute interview with Prof. Ramankutty, and more interestingly, a link to Anthropogenic Biomes.

Haven't listened to the interview yet, and I'm still getting over the heebie jeebies over this take, but I'm trying to be fair. There could be some value here, in the sense that you've gotta know what you're up against. I've looked at their google earth workup (available here, through the latter link), and while it's not so great at high resolution, it may well provide a point of view that's practical, if not ethically defensible.

(BTW - if you don't have a good fast connection - don't even think about the google earth aspect. While Google Earth, and the uses to which it's being put, is pretty amazing, you do need a fast connection. If you have that, it's great, though there are a few glitches you might encounter.)

Here, for instance, is a screenshot of much of the western portion of the Northern Hemisphere, as portrayed from the "anthropogenic" view. (I'd call it "anthropocentric", the basis for my own private chilly willies, but that's just me.) The capture links to a larger screenshot more readable. The legend, with its single lonely reference to anything resembling something not having to do with humans, and such a pastel green that you can hardly detect it on the map, tells it all:

I've also used google earth to scan over the Amazon, Madagascar, India, and Arnoldsville. You probably didn't need the warning, but I'll let you enjoy the horror of it all.

The Anthropogenic Biomes page is a part of The Encyclopedia of Earth, which in turn is an extraordinarily homely child of its parent, The Earth Portal. From all indications The Encyclopedia of Earth has a lot to offer, but they really should fire whoever designed their front page. It's truly ghastly. Even I can see that.

Addendum: As Glenn pointed out, and I already knew, my heebie jeebies come through in the post, but not the reason for them.

I'm so effing tired of everything having to revolve around humans in order for anything to be valid. You can't, for instance, merely argue for the conservation of tropical rainforest for its own sake, you must *defend* your arguments by invoking the drugs, or food value, or genes, or hitherto undiscovered benefits that the biome might confer upon humanity. It goes on and on and on in this manner, wherever we look.

It was, I think, the promotion of this effort that bothered me, more than the results. Had it been presented as a complement, it would be fine. But it was presented as a new, necessary paradigm, something *better*: we might as well get with the program - all these ecosystems are going to be gone, don't bother teaching or researching the remaining 20%, it's irrelevant. Had it not been presented that way, I'd have thought this a fine addition to our understanding.

So I suppose I'm reacting more against the self-promotion, rather than the content.

Wednesday: 28 November 2007

Our House Spiders Are Bigger Than Yours  -  @ 08:18:56
At the risk of exposing my poor housekeeping skills, I offer this. Actually I'm always rather pleased to find one of our harmless collection of large spider species wandering about the house. They help with the housekeeping. I generally tend to put them outside, as I did this one. I imagine they're grateful, and much happier. On the other hand it was 28 degF this morning so this one may have enjoyed a short-lived pleasure.

(I sampled some of my students last night with printouts of this specimen. Though they were uniformly interested, they were also uniformly appalled, and uniformly thought "tarantula". Bless their hearts, they were uniformly clueless.)

Yesterday I happened to look down while swiveling away from the nerve center and the lighting backlit several glowing eyes looking back at me from the darkened floor, against a small table. The camera flash itself wouldn't illuminate the eyes, but the fluorescent light in back of me did. Since the four small photos were taken from non-advantageous distance and angles, the subject itself is not so distinct, but the headlights should be:

Some closeups, linked to considerably larger versions:

I vascillated between a wolf spider (Lycosidae) and a fishing spider (Pisauridae) but those eyes on the top of the head rather than continuing a top row in close proximity (Dolomedes fishing spider here) decided me on wolf spider. This may well be the same species that puzzled me last June. A bit under 2 inches long, body length.

As to which wolf spider, looks like everyone has the same problem. Could be a Pardosa, could be an Arctosa. I'm inclined toward the former, but common names like "shore" and "littoral" aren't exactly evocative of this environment.

What a beauty she is! And I always think "she" with large, proud spiders, but with wolf spiders it could be a "he". I particularly like the form of the cephalothorax, which has a spread to it not unlike a helmet or shield. She was on the move in the photo below, so those legs are in apparent disarray, but they are not damaged. This photo gives the best indication of her eyes' arrangement, and the best view of those lovely long pedipalps.

She was extremely cooperative and active in a non-frantic way. And then we went for a walk outside.

Monday: 26 November 2007

Fuzz  -  @ 06:55:10
The rain chances for yesterday were good, but only resulted in 0.09 inches of accumulation, though the day was misty and drizzly much of the time. Today's chances look all but certain - lots of rain on the way and just about to arrive. Mark should be having tons right now.

The Northern Red Oaks seem to have dropped a modest crop of acorns this autumn. The White Oaks seem to have punted. Red Oak group species take two years to mature their acorns, and so may have been relatively unfazed by the intense cold of April, which occurred during oak flowering. So this may explain the dearth of White Oak fruits this year and if so predicts a poor Red Oak crop next year.

Here's two Northern Red Oak acorns. Recently dropped acorns had the dull white appearance of the one on the left - I initially thought it was fungal growth. Glenn idly demonstrated that rubbing the freshly picked "white" acorns such as you see on the left, resulted in the polished attractive fruit on the right. We looked a little more closely at this, and the drops of water will be explained shortly.

The rubbing action is interesting. Initially it's somewhat ineffective, but as you get going it becomes more and more efficient at revealing the dark red brown seed coat. The closeup shows that the fruit is covered by tiny hairs, and a little pile of fuzz can be seen in this one. I'd guess that at first the rubbing is accomplished only by mechanical pressure but that as a little fuzz begins to accumulate it acts as a fine sandpaper on the rest of the coat of hairs.

And fine they are indeed, these hairs. Given the size of the acorns, the hairs must be in the tens of micrometers long at most.

You might think that this pubescence, the coating of tiny hairs, would be a taxonomic feature worth noting in botanical descriptions, but it is not mentioned at least as often as it is. And by the way, there's nothing to say that this *isn't* a fungal coating, but the uniformity and difficulty of removal suggests that it is a plant part, and not a fungal growth.

There is a waxy sort of feel to the debris, and I thought that maybe the hairs were water repellent, but this is an illusion. That's the reason for the drops of water placed atop the acorns in the top photo. And the water does bead up on both versions.

However gently smearing the drops shows what's really happening. The drop continues to bead on the rubbed acorn, but spreads evenly across the hairs of the unrubbed acorn on the left. The hairs are clearly not water repellent but in fact hygroscopic, attracting, spreading, and probably retaining water.

There are probably as many ways of preparing a seed for germination as there are plant species, especially in temperate species that face a winter. There are certainly many seeds that *do* shed water for at least a period of time. In this case it looks like Northern Red Oak seeds would like to encourage water to enter the seed as quickly as possible.

UPDATE: Glenn points out that oaks may be similar to buckeyes, in producing seeds in which the embryo does not dry out and will die if allowed to dry out. In that case it would be important to have a flow of water through the seed coat as soon as the seed matured.

The Baskins, Carol and Jerry Baskin, of University of Kentucky, have written an exhaustive, 600+ page treatment of seed dormancy and germination, covering hundreds if not thousands of species. My edition is 2001, so in a field of study as densely populated as this one (and believe it or not this subject of seed dormancy is a huge field) there must now have been many thousands of investigations to be added to any new edition. Still it's useful, if a bit terrifying to bite into.

Oaks tend to have a primary dormancy that requires a couple of months of cold to break. At that point the radicle (root) and epicotyl (shoot) begin growing and will emerge. But cold treatment only works if the embryo inside is moist and capable of cellular activities. Seeds dropped from the tree are dry as dust, and must therefore soak up water before any of this activity can commence. It seems as though the fuzzy pubescence would aid this uptake of water.

The use of plant hardiness zones probably deserves its own post, but that wikipedia link does a fairly good job of describing the confusing contentions of the last decade or so in producing a new updated map acceptable to all parties. USDA is purportedly updating its 1990 map, but it's been promising this for a number of years now. Maybe one will be revealed after the Bush Administration leaves office. The 2006 Arbor Day Map places us here in Athens in Zone 8 (10-20 degF minimum temperatures), at least a half a zone warmer (7b: 5-10 degF minimum) than the USDA map of 16 years prior.

The Wikipedia article also does a good job of pointing out the problems, technical and practical, with such hardiness zone maps. Hardiness zone maps have more to do with what you can or cannot grow than with what can or cannot survive over the multigenerational years as a native. So it's probably doubly inappropriate to apply such maps to such arcana as seed dormancy breaking, but the trend still brings up an interesting question: what happens to populations of plants requiring a minimum number of days at some minimum temperature before the seeds will germinate, when those conditions no longer prevail?

Sunday: 25 November 2007

Autumn 4: Three Trees  -  @ 06:16:24
The autumn has given me the opportunity of a special time for tree identification, particularly *this* autumn. The progression of leaf change and the colors presented have been very precise, illuminating species one by one. Currently the white oaks, later than most, have been showing their colors.

Here are three trees, one known, one unknown, and one discovery.

Here's the known: Northern Red Oak, Quercus rubra, which I present as a positive control. The vertical white striations in the bark of the trunk make this one very apparent (now, but see below for the second tree). There are acorns beneath this tree, and others that I'd identify as Northern Red Oaks. The acorns do fit the description in Radford (Manual of the Vascular Flora of the Carolinas.) I'd earlier claimed that the NRO leaves had just fallen with no color transition, unlike all our other tree species which have undergone a magnificent display. I now know that I was confused by tree number three.

Of the bark, Radford says (without mentioning the striations):
Bark of trunk dark brown with low broad ridges.

Golden Guide says, and again no reference to striations:
The dark brown to black bark is ridged and furrowed.

The leaves at this date are pretty ratty, and none of my shots from ground level to subjects 70 feet up really all a lot of identification of the typical red oak leaves. So you might as well not click on the photo.

This second tree, growing close by, is in similar leaf presentation but has no acorns beneath it, and the bark of the tree in no way resembles that of the northern red oak above. At the moment I'm baffled as to what it could be. There are a number of NRO lookalikes: Swamp Red Oak, Q. shumardii, Black Oak, Q. velutina, and Scarlet Oak, Q. coccinea.

At the moment, given the poor leaf samples in the photos, I couldn't even say it was in the Red Oak group. It could be in the White Oak Group, especially given the absence of acorns, but I am certain it is not a White Oak, Q. alba, as there are numerous examples of that nearby and this is nothing like it. Nor is it a Tulip Poplar.

The fun discovery was of the third tree, of which there are a number of very large specimens up around Troll Rock. Intermixed are Mockernut Hickories, White Oaks, Northern Red Oaks, and Tulip Poplars. I'd previously and casually pegged this one as a NRO. The early absence of leaves dropping without fanfare led me astray, but the few remaining in the uppermost branches are without a doubt *compound* leaves, and I'm pretty sure in the photo below that there are two opposite one another.

This, along with the absence of color (which the alternately compound hickories showed their usual magnificance this year) identifies this tree, and Glenn confirmed it. It's an Ash - Glenn says White Ash (aka American Ash), Fraxinus americana. An alternative might be Green Ash (aka Red Ash), F. pennsylvanica.

Clearly the bark is nothing like a Northern Red Oak, nor is it like the second, unknown, tree above which in any event is displaying leaves in a NRO fashion. Radford does not have a good bark description but Golden Guide to Trees of North America describes it:
Gray bark with diamond-shaped ridges appearing on the trunks of older trees.

Nice to discover that several very large individuals are something I had no idea was here.

The problem with all of these trees is that the leaves (and twigs) are inaccessible. The relatively close growth of the large mature trees has prevented lateral branching in most of them so that the more typical leaves cannot be found closer than 50 feet above the ground. I have to wait for them to drop, and then they're mixed in with all kinds of potentially confounding leaves of other species.

Saturday: 24 November 2007

Gentians Again!  -  @ 06:01:59
You've seen this before, late last October 2006, so it's a repeat in a way, but one well worthwhile under the circumstances. Last year I noted a week later that deer had cropped it so tomorrow I'll go down with some wire cages to protect it and another plant Glenn found a bit further downstream.

It's Gentiana saponaria, Soapwort Gentian, Harvest Bells, or Closed Gentian. Last year it flowered a month earlier, and I've been keeping an eye out for it all this time, gradually assuming it had been extirpated by the deer or compromised by the hot dry conditions this year. But here it is, and as I said, there's at least one more plant a bit downstream.

It's a plant of wet or moist environments, growing directly out of the muddy banks. And of course we just don't have all that many flowering plants this time of year, especially none so delicate and blue!

Flowers that remain closed are called cleiSTOgamous, and a plant that has cleistogamous flowers is called a cleistogene. Some species produce populations that are mixed cleistogamous and chasMOgamous (open flowers), but not this one apparently. And even individual plants can produce mixed states, but again not this one.

I'm not sure what the primary motivation for cleistogamy is - it may be one of those multitasking things. It could originate for protection of development of seeds, coincidentally limiting the plant to self-pollination, or it could be simply to ensure self-pollination. While the latter is usually assumed, it's an unusual strategy - there are at least an equal number of mechanisms that prevent self-pollination and ensure cross pollination. Cross pollination is usually considered advantageous in the interest of promoting increased genetic variability; self pollination is the opposite - achieving a state of homozygosity (and perhaps increased phenotypic variation). There must be a ton of literature on this subject.

Whatever the biological arcana, it's lovely to find!

Friday: 23 November 2007

Thanksgiving  -  @ 05:07:01
Our Thanksgiving day was spent here, and I do not envy anyone who did travel. The US Thanksgiving is one of my favorite holidays and we were invited to share it with our fire chief and his wife, along with their son and daughter-in-law and another favorite and favored firefighter. Glenn and I had a fine time Wednesday night making bran muffins and cheesecake, running interference with thankful cats, and then finished the stuffed mushrooms on Thursday morning. And then we travelled all of 3 miles to our hosts' house where we had a thanksgiving dinner that couldn't be beat.

Early Thursday morning the skies opened up, as expected, and we had rain. The front moved northeast in such a way that, as not expected, it progressed its length above us, dropping a total of 1.7 inches in six hours. Needless to say none of us complained about this. Doubtless there were those who did, but I didn't run into any and wouldn't know any of them, not for long, anyway.

Wednesday: 21 November 2007

Rain Shadow or Rain Dump?  -  @ 07:07:30
We have a great chance for rain tonight and tomorrow, Thanksgiving Day, when we might also have storms. From the National Weather Service:
Area forecast discussion. . .Updated National Weather Service Peachtree City Georgia
530 am EST Wednesday Nov 21 2007

Short term /today through Friday/...
finally transitioning to more typical winter pattern for the southeast...with some welcome rain in the offing. Models have initialized well for a rather complicated scenario unfolding in the central/Southern Plains. GFS seems to have a slightly better handle on the placement and timing of the developing surface low in OK/Texas and the upper vorticity maximum over Mexico. Moisture streaming into Southern Plains in advance of this system. Surface high along Georgia coast will gradually give way to this approaching ystem...bringing US a soggy and potentially stormy Thanksgiving.

Well that's ok by me - a perfect scenario to be thankful about.

And speaking of rain, it turns out that I've been keeping precipitation records for the area outside the kitchen door since May 2002. (If I'd been *really* good I'd've been keeping them since May 1991.)

So I decided to compare monthly totals between the "official" Athens records, given by this site, which has monthly data going back to 1898. It's my usual source for data and measurements are taken at Ben Epps Airport, about 10 miles northwest of us.

First, here is the Athens vs Sparkleberrysprings plot. I've color coded the data points by year. Above the diagonal indicates that the area outside our kitchen got more rain than Athens, below the diagonal indicates the opposite:

There is clearly a preponderance of points above the diagonal, in fact our place has received more rain on 46 out of 66 months, 70% of monthly totals. This has amounted to a difference of more than 40 inches of rain in the past 5+ years, or about 15.5% more rain here than in Athens ten miles away.

I find that pretty astonishing. Particularly since I've groused many times that Athens has gotten rain when we haven't. Assuming that the measurements taken at Ben Epps are accurate (I know *mine* are), my impressions have been incorrect.

Here's a screenshot of the breakdown by year, month, and season. The inner numbers are the differences, in inches, between Athens and our area: Us minus Athens. We still have Nov and Dec to go in 2007, so I just used a "zero" difference for the time being, and the same goes for Dec 2001 through April 2002, when I apparently didn't acquire rainfall data here at SBS.

Looks to me like we have had a preponderance of rainfall inches in Feb, Sep, and Nov, and a very slight deficit in Jun, significant only for the (minus) sign in a crowded field of (plus) signs. 2004 was a very significant year of extra rainfall, accounting for 15.3 inches of the 40 total inches of excess.

As it turns out, I started the blog in July 2004. September 2004 had several observations on rainfall. And again at the end of November 2004, I noted this. That was the year of Hurricanes Ivan, Frances, Jeanne, and Bonnie. It's certainly possible that those events skewed the distribution inordinately, but I would have to do a chi-square test to be sure. In fact, I will do that once the data are in for Nov and Dec. It looks like the table is well-suited to an analysis of variance.

The reporting station for Athens is to our northwest, and that is also the source of prevailing winds throughout much of the year, excepting late summer. It may be that that is the explanation - rather than being in the rain shadow (which we might be if we were more than a mere ten miles away), we are within the rain dump.

I'm still working on the Atlanta-Athens comparisons so you don't have to see those today. ; - ) 

Tuesday: 20 November 2007

Autumn Page 3  -  @ 08:39:15
Not to belabor the point, but this is quite an autumn, here. Along with the drought, it is, and not perhaps coincidently, a one-hundred year autumn. I declare it so, and my god, why not, if we must endure the bad along with the good? It's been one that continues the extreme dryness and warm daily temperatures punctuated by a night or three of subfreezing weather, and has resulted in unsurpassed extravagance.

Yesterday I took my walk down to the southeastern border of the property and worked my way along the creek northwest. Carefully of course, since this is deer-hunting season! I've mentioned several times that this has been an unusually brilliant presentation of autumn colors. I first started thinking, well, this is unusually different, around the first week in November. And then a week later I thought *whoa* this is really different. But yesterday, when I sat beneath the white oaks and sourwoods and beeches, I was completely floored.

A week ago I noted the sourwoods and hickories, and thought *that* was great. The beeches had not yet turned, and neither had the white oaks, both dominant species in our mature forest but the presentation was magnificent. I was impressed.

Sometime in the last week the beeches and white oaks did start to turn. The hickories have started to drop their deeper golden-orange leaves, leaving vast carpets of dazzling yellow and deeping orange colors on the ground - you know when you're standing in the area of a hickory.

But yesterday I stood under our old beeches and huge white oaks and couldn't believe what I was experiencing - it is truly and hands down the most amazing display I've ever seen, and as close as I've come to a religious experience. I honestly felt like crying, and it didn't make it less so knowing that I had been so manipulated by reflective electromagnetic radiation bandied about in a manner I was unaccustomed to. (In truth, I wept as a child being pulled from the mountains of North Georgia under similar circumstances, four decades ago. So there shouldn't be any surprise at this.)

It's frustrating not to be able to capture it, but this is the best I can do. The camera is completely inadequate to deal with it. I've thought about a wide angle lens but that wouldn't do it either. An interesting thing is how *protracted* it all is, too. The sourwoods are *still* a brilliant red on the trees, and I'm seeing individuals I never knew were there. Even the sweetgums, bless their overabundant hearts, are trying their best. The dogwoods are now turning and I'd not considered they'd contribute in a spectacular way, but they are. And I'm seeing a dichotomy of maples that suggests we may have chalk maples as well as red maples.

So today I revert to my kindergarten years. I'm done with pre-Thanksgiving work, and I'll go out, with camera, and try to sample from each cohort of colors, with the intent of photographing and pulling off limbs for identification. The oaks are so amazingly different - and I know we have turkey oaks, post oaks, white oaks, northern red oaks, and blackjack oaks, at the very least. I suspect scarlet oaks and possibly a number of scrubby species. (The red oaks, of all of them, have been the least showy - as far as I can tell they went from green to gone.) I can tell already that each is extremely distinctive, but am not quite sure yet which is which.

I plan on tagging the blackgums, Nyssa sylvatica, our *special tree*, to make sure I know where they are, since more of them have appeared than I knew were there and are evident by their extreme scarlet fall leaves. Otherwise, they're extremely modest trees, but are well worth knowing for their contributions to autumn wildlife mast. The wild azaleas and their vaccinium relatives are distinguishing themselves too, with the former turning and the latter sparkleberry species still green.

Bev mentioned in comments that it was her experience that a dry late summer and autumn led to a brilliant fall presentation, and I believe it. I still have this niggling feeling that all cannot be good, given our incredible drought, but it surely does look wonderful.

Monday: 19 November 2007

November Butterflies  -  @ 06:15:45
Yesterday's walk along the creeks, in unseasonably warm weather, netted a few interesting observations. Even though our rainfall has continued to be as sporadic as ever, dropping less than an inch once every three or four weeks, the creeks now have more water in them. And that includes SBS which completely dried up a couple of months ago. Given the lack of rainfall to explain this, I have to invoke "evapotranspiration", particularly the transpiration part, as one of the major reasons for the water table decline. With the trees in particular now going dormant, they're not sucking water up out of the ground and even the paltry groundwater supply is sufficient to give a net increase in level. That's my hypothesis, anyway. Pretty amazing, that a forest can control water levels to that extent.

It wasn't until I checked the photographs that I realized I had encountered *two* species of butterfly, not just one. They were solitary individuals, and this one flitted briefly about, just long enough to catch an identifying pic:

It's a Gulf Fritillary, Agraulis vanillae, and while not uncommon certainly, the first one I've seen this year. I see I didn't see any last year either, but there are a couple of photos of an adult in Sep 2005 and a caterpillar a month earlier. Passionflower is its larval mainstay, and we've certainly had a fair number of undamaged plants this year.

That individual took off and then returned, or so I automatically assumed without further ado. But no, this one is a Question Mark, Polygonia interrogationis, one of the Anglewings. The white mark on the underside is the preferred character for this species.

"Larvae feed on elm." We do have elms, but they're not especially abundant in the immediate area. Apparently they also feed on hackberries, as I noted last last July, and we certainly have plenty of those.

I also see that I don't appear to have observed this species around here before. Nice wing margins!

Sunday: 18 November 2007

What You'll See When the Asteroid Comes  -  @ 07:26:51
Answer: Not a lot. Fortunately there's nothing predicted to hit the Earth in the near future.

In 1908, the famous Tunguska meteor hit Siberia, resulting in widespread devasatation. It was estimated to be about 165 feet in size, and typical of asteroids under 50 meters it exploded in the atmosphere, rather than impacting as a single body.

In July of 1994 Comet Shoemaker-Levy slammed into Jupiter in a train of mountains over a period of several days. The devastation was visible even in small telescopes as planetwide dark patches in the polar latitudes. It got people a bit uneasy, and cataloging of the Near-Earth Objects began. There are now 5000 asteroids that approach Earth from time to time - only 906 at present approach closely enough (5 million miles), or are enough of a size, to be considered Potentially Hazardous Asteroids, or PHAs.

Near-Earth Flybys are not at all uncommon - each month of JPL's Space Calendar includes a few. But these typically approach no closer than a million miles or so. On November 11, for instance, 2007 VX83 approached to a distance of 0.0077 astronomical units, or 750,000 miles, and that's either very close, or quite a comfortable miss, depending on your point of view.

Still, it has not been unknown for the discovery and the approach to coincide. 2002 NY40, discovered just a month previous, came to within 326,000 miles and was observed on its closest approach through telescopes on August 17, 2002. NY40 has a diameter of 700 meters, or 0.43 miles, and that's a pretty healthy size.

2004 FH, a 100-foot diameter object, passed within 26,000 miles of the South Atlantic Ocean on March 18, 2004. This kind of event probably happens every couple of years. There's a nice description of the anxieties this approach elicited here.

Of the possibles: Asteroid 1950 DA may impact on March 16 2880. It's larger than half a mile in diameter. 2002 NT7 takes a shot on Feb 1 2019, and is 1.2 miles in diameter, but collision is unlikely. And on April 13 2029 (yes, a Friday), 1000-foot diameter 2004 MN4 will pass as close as 18,000 miles.

JPL's NEO webpage continually updates close approaches and statistics, which are interesting to contemplate. Discoveries continue to be made at a constant rate, indicating that there are more out there than have been discovered. Nearly 300 discoveries have been added to the 5000-member NEO list in 2007 alone. Most of these are rather small, but 728 so far are one kilometer or larger in size. That makes a *big* impact.

You can make plans now, at JPL's NEO Risk page. And there's even a measure, the Torino Scale, to assess the potential damage and likelihood.

This is all very Earth-centered. But flybys and close approaches also occur with other planets and other asteroids. I modified a small program to examine each of the nine planets and 173,000 asteroids, including NEOs. The program simply calculates the coordinates of each object at 2.4-hour intervals and reports if two objects come within 100,000 miles of each other. Seldom do objects approach much closer than that, but there are a few each month (for Nov 2007-Jan 2008, so far) that pass as close as 10,000 miles. The record at the moment is for Asteroid 1990 EN1 (3 mile diameter) and 2003 BM72 (2 mile diameter) to approach within 7100 miles on Nov 21 at 8:00 AM UT. ; - )  A close contender occurs on Jan 2 2008, just before midnight, when 2001 QQ42 (half mile in diameter) approaches to within 8100 miles of 3659 Bellingshausen (3 mile diameter). Of course both of these pairs are more than 200 million miles away, in the Asteroid Belt, but if a tree falls in the forest and no one hears it, did it really happen? Shouldn't someone be checking on these things?

So back to the question: what would it look like? Of course it depends on a lot of things, but most likely you'd never know what hit you. Only in the last few seconds, or minutes, depending on the size, would anything be visible. So you can give up the romantic notion of huddled masses of humanity preparing their obituaries while stealing anxious glances at a mountain hanging over their heads.

Here's a plot of apparent diameter versus size and distance. For reference, the moon (and sun, in artistic coincidence) are about a half degree in size, when we look at them in the sky. The colored lines each show an object of a different size ranging from "the size of Texas", or thereabouts, down to 50 feet in diameter. (Note: there's only one inner system asteroid, Ceres, that approaches the size of Texas, and it's safely placed in the Asteroid Belt.)

Ceres in the sky would appear to be the size of the moon only in the last one minute of approach, assuming 10 miles per second approach velocity. An asteroid the size of the dinosaur killer of 65 million years ago, say 5 miles in diamter, would appear the size of the moon only in the last 2 seconds, and that would be compromised by considerable atmospheric effects by then.

How about brightness, though? Asteroids are cataloged according to absolute magnitude, and there is a relationship to size that can be calculated given certain assumptions. The plot below shows the brightness of asteroids of certain sizes in the last few days of approach. For convenience I've labelled the apparent magnitudes with what we're used to - dim stars at the verge of visibility are perhaps Magnitude 6. The full moon is about Magnitude -12.5.

An asteroid the size of Ceres, under ideal conditions of reflection angles, might appear as a bright star as early as four or five days ahead of its impact. Something the size of the KT asteroid, 5 miles in diameter, would only achieve visibility a day ahead, and would appear as a bright star about 3 hours before impact.

Let's look a little closer at what happens in the last few minutes.

At 1 minute before impact, Ceres would show the interesting combination of being larger than the moon, and about 10 orders of magnitude brighter, about 10,000 times as luminous. On the other end of the scale, a 50-foot rock would achieve star brightness only in the last 20 seconds or so. The dinosaur killer might have been as bright as the full moon (but much smaller) as early as 2 minutes before impact.

Plenty of time to write that obituary!

Friday: 16 November 2007

Autumn Page Two  -  @ 07:15:41
Yes, we are still here, and thanks for the inquiries! It's been a distracting week. Not bad, but full of odious responsibilities and self-thwarting impulses. More on the latter, perhaps, but it involves a resurgence of my fascination with asteroid-asteroid collision predictions.

It was lovely to hear the rain start up around 1 AM Thursday morning and continue through most of the night, as a front finally broke through and dumped 0.78 inches of rain by dawn, our first since October 22. And no, it wasn't Georgia governor Sonny Perdue's Tuesday demagoguery at work - the statute of limitations on miracles by exploitation expires more rapidly than that, surely. If the heavens don't open up as you posture, then it didn't work, no matter how carefully you plan your prayer session around the National Weather Service's forecast. You don't get a 36-hour window.

Thursday day was notable for its winds, and we don't have a lot of wind here. When I left for work on Wednesday afternoon there wasn't a leaf on the south deck. Thursday morning it looked like this:

A lot of those are maple leaves, from red maples that I planted in 1991 to cover a sunscorched bare expanse of slope. The maples are now well over 40 feet tall, and provide the shading feature for the woodland shade garden that has gradually grown up. I'd planted them, in my naivety, from seeds gathered from outstanding trees lining the physics building on campus. Of course it turned out, as I now well understand, that the progeny looked nothing like the parents, and what a sorry autumn presentation they've made all these years. *This* year, on the other hand, and for the first time, the leaves turned a brilliant yellow, yet another indication of the role environment can play in trumping bad alleles.

You get just a taste of it in the background of the photo but as I mentioned a few days ago the autumn here has been absolutely dazzling. I'll have to go down today to see how the various oaks are doing.

Last night's fire training involved crawling through tight places with full turnout gear, including BAs. Our resident carpenter had constructed a fine torturous fake wall with tiny doors and windows. Somewhere along the way I either cracked or pulled a rib, or chest muscle or something. I heard it go but didn't think much about it until a coupla hours later when I had a good sneeze and realized something a little more significant had happened. We'll just have to see how it sorts itself out.

Monday: 12 November 2007

Fraud Alert!  -  @ 09:12:46
Makes for an exciting morning when you get a call from your credit card company asking about recent significant activity on your credit card.

We only have one credit card, well, two - one for those emergencies when some rare silly glitch has inactivated the other one. We're terrible consumers to start with and not at all a credit, so to speak, to the credit company since we always pay bills on time and have never had debt.

Anyway, Glenn called back and it appears a purchase of gas was made in Cornelia and another purchase at a walmart in Commerce, both north of here. Something about a racetrack in Commerce, too. Neither of us could remember being in either of those places or doing either of those things. Various sorts of confirmatory information was exchanged and the conversation ended with the account to be closed.

Then we thought - this is a potential scam in itself. So we called what we knew to be the company independently and were relieved to find that the account had indeed been closed, so the phone call was legit. But let it be a lesson to us - there are many potential layers to these onions.

I'd hope we'd get some idea of what transpires, and of how credit card theft in these particulars occurred without a physical credit card. Although neither of us has recently, we do do occasional internet purchases (and that was my initial worry, that that's what all this was over but apparently not). So that could be the source of a leak, but how this paltry theft could have occurred through an internet transaction security breach is a mystery, if so. Can't think of any other way this could have happened, unless a cashier at a previous place of purchase somewhere was stealing credit card numbers.

I admit to something of a naivety about the intricacies of all this although I'm very much aware that it happens, and that we watch out for it. Glad the company called us to check, though.

Any explanations? Nightmare stories that you care to add?

Sunday: 11 November 2007

Autumn Page  -  @ 07:08:46
No, not the latest craze in human female baby naming, but a tradition that many of you have already gone through (or will not, particularly). It seems that we in northeast Georgia either lead the way in the spring, or follow way behind in the autumn.

Photos are linked to substantially larger ones, if you care to click on them.
I've never really done much presentation of autumn colors around here, because autumn colors have never been particularly spectacular. But this year. Who'dathunkit? I would have guessed a paltry autumn, because of the drought, but on Saturday a wave of certain species, and not others, were at the peak for display, and a display that I can't recall being matched in the last fifteen years. Maybe it's because of the minute amount of rain we had three weeks ago, followed by the last week of unseasonably cool day and night temperatures.

And that's another odd thing. While I know that Black Walnuts are inclined to drop their leaves without fuss and ceremony, far earlier than most of our trees, I can't recall such a sharp demarcation in autumn colors. The theme for this page could be hickories and sourwood, because with one odd exception white and northern red oaks are still in green leaf (in mid-November!). As are dogwoods (just turning), water oaks (never offer much of a display, and drop over a period of months), and American beeches. Tulip poplars, not much of an autumn celebrant to begin with, have been dropping leaves since August, as have our post oaks and occasional elm. Our river birches just turned brown and the leaves oddly persist on the trees. Pale yellow large-leaved sycamores and mulberries just dropped. Red maples? Not so much, oddly. Sweetgums, about as usual, generally rather blah, with a few exceptions. A friend noticed a grove of a dozen black gums along about midsummer, and although that was the original goal on Saturday, they turned out to be something of a disappointment.

So I suspect that in the next week or two there will be another spectacular presentation of white and northern red oaks, and American beeches.

Above is a single specimen of mockernut hickory, contrasting with the surrounding northern red and white oaks. Below are pignut hickories, and particularly among them is *the* pignut hickory, the one I estimated last December to be in the range of 130 years old:

The sourwoods are magnificent, and such a quiet tree normally loses its identity in a forest of which it might otherwise seem such a small and infrequent part. But right now it's easy to see how many of them there are, tucked in among the still-green oaks and beeches.

Perhaps presaging the next couple of weeks, a single branch of a white oak has turned red, among all the others still green on this large tree:

Saturday: 10 November 2007

Homely  -  @ 04:58:27
I mentioned a few days ago that we had planted a number of natives into pots this year. It's a good thing we did because things really didn't do well at all in the ground if they were first-year plants.

One of these was this superficially homely plant, Woolly Croton (aka, hogwort, doveweed, or hogweed), or Croton capitatus. I considered writing this in a gustatory manner, praising its virtues and dressing it in emperor's clothing, but all that manipulation stuff has gotten rather old after seven years. It's just a downright ugly plant. Nonetheless, like a train wreck, it is not uninteresting. As you can see, it earns its "woolly" descriptor!

It's one of the many many members of the Euphorbiaceae, the Euphorbia Family, which contains 300 genera and 5000 species. The Croton genus in the US is around 50 native species and tends to have members that are ungainly and awkward, many even more so than this one. We have 8-11 species in Georgia, and I've recognized several of them as moderately annoying garden weeds, passionate about sun and heat.

Although not too many people have inquired about what's in flower this past summer, it's even my tendency to take a quick look around for color, and thereby undercount all those nonflashy plants that are doing their best for the species. This one is in flower, and a bigger mess you can't imagine.

We have an inflorescence consisting of a number of imperfect flowers of both sexes, and if they're arranged in an easily discovered pattern it's hard to see. The female, pistillate flowers are generally beneath the male, staminate flowers. With all those hairs it's a wonder the pollen ever finds its way from where it is made to where it's supposed to go.

Along with the sad tomatoes, this plant bit the dust over the last few nights of freezing weather. Yes, I said *freezing* weather! We've actually been 5-10 degrees below normal for the last week or so! I should have brought it inside, because I wanted its seeds and now it may not have finished making them.

About those hairs: they're not just your ordinary, garden-variety boring structures. These are *stellate*, which means starlike, of course, and consist of branching parts. And they're quite dense, too.

I ran the species through the Lepidopteran HOSTS Plants database, figuring that if there were any lepidopterans that used this plant for caterpillar food it would probably be bagworms or inchworms or something like that. And there are a few noctuid and geometer species, but there's also Anaea andria, or Goatweed Leafwing, a very pretty and large leafwing. Nice website there, by the way: "adults play dead when handled." It also mentions that the habitats that encourage the larval food plants are in decline due to development, at least in Florida, and so the butterfly species itself may be at risk.

Although "croton oil" is mainly harvested from C. tiglium, C. capitatus here also produces the nasty phorbol esters that are typically made by species of this genus. Phorbol esters are tumor-inducing and proinflammatory, and it doesn't take much to do you in. It appears there's something of a market for its use in "skin rejuvenation". Apparently you put it on your skin. The skin dies a horrible death, and then you grow a new, fresh one, or something like that. You'll have to tell me how it works for you. When I do carcinogens it's because they make me feel good.

Euphorbs in general produce copious numbers of toxins. Castor bean, Ricinus communis, planted for its pretty seeds, produces quantities of the toxin ricin in those pretty seeds. There are always stories of kids getting their stomachs pumped out with the local botanist called down to identify the contents. And ricin of course is one of the many darling terrors du jour marketed for our titillation in the last few years. Many of the ornamentals have a milky sap that is at best irritating and at worst caustic ("one drop in the eye causes blindness!").

Most of the euphorbs you come across will be ornamental, Old World species, attractive for their spines and odd growth habits, in some cases flowers. Poinsettia (Euphorbia pulcherrima) is one such, and so is crown-of-thorns (E. milii). The subset of spiny euphorbs is often mentioned as being the Old World equivalent to the New World cacti, to which they are relatively unrelated but afford a nice example of convergent evolution.

Even here in the US we have 60 genera of euphorbs represented, though they probably tend to be those anonymous weedy plants that you come across toward the end of summer and don't know what the hell they are. There are, for instance, over 60 species of sandmats, Chamaesyce. Copperleaf and 3-seeded mercury include another 23 species in the Acalypha genus. And we have our own New World Euphorbia, at least 74 natives, going by the common name of "spurges". There are four native Manihot species in the southwest. M. esculenta is cassava, a food staple in many countries in South America. And then there are what look to be some very nice euphorbs: noseburn, 15 species in Tragia, all native. Toothleaf, 7 native species in Stillingia. And Phyllanthus, or leaf-flower as you probably guessed by the genus name, 14 native species. I'd bet many of these are xerophytic, and HOSTS database has over 70 listings of moths and butterflies that use the family as caterpillar food, in the US alone. If you had to choose a family of plants to investigate, you could do worse than to choose Euphorbiaceae. Of course everyone will think you're growing weeds.

Wednesday: 7 November 2007

More Comet Holmes  -  @ 08:02:22
On Saturday, Nov 3 3AM,, I presented some non-telescopic photos of Comet 17P/Holmes. Late last night, Nov 6 11pm (3.9 days later), I took some more.

As you recall, Comet Holmes did a funny on Oct 24 and increased in brilliance by a million-fold or so. If you haven't gotten out and looked at it you're missing something really fine. Astroprof has a couple more interesting posts since Saturday, on this. The latest is after my own heart, a lamentation that the MSM has, in its well-documented dullness, barely picked up on it. Sunday's post provides a nice explanation of the changing brightness of the comet, among other things.

I compared the photographs taken under the same photographic conditions. I didn't photoshop the scale, but I did a little rotation and matched up the brightness slightly according to pointer stars. The photos below are sections of larger photos that you can open up in new windows by clicking on the photos - opening them up side by side and comparing is pretty neat:

Here it is on early Nov 3:

And here on late Nov 6:

Here's a small skymap that corresponds to this field of the sky. It makes more sense in the larger, linked versions. The curved track shows where the comet is on the indicated dates. It pleases me that that is where I saw it, from the above photographs:

The magnitude 7 stars that I've labelled A and B are, respectively, HD 22417 and HD 22389, in the Henry Draper system that I prefer. Even with my crude photography you can see that the comet has changed. It has increased in diameter, and its density is lower. Overall it has nearly the same brightness but the concentration of luminosity is lower as it expands. And of course it has moved significantly over four days, in the 10 o'clock direction in these photos.

I did a few rough calculations. Skymap Pro, when fortified with recent comet elements, tells me that the comet is 242.4 million kilometers from us (this distance hasn't changed much in the last four days). I estimated the angular distance the comet has travelled in the last four days and it turns out to be about 2.8 million kilometers. This is an apparent distance, since the comet may not be travelling at right angles to us, but I bet it's pretty close. The comet is therefore travelling at about 8.3 kilometers per second.

Even better, I estimated the angular size of the globular comet on both days. We're only seeing the dust cloud in these photos, the gaseous halo extends much farther out. The dust cloud was about 0.14 degrees across, or 580,000 kilometers in diameter on Nov 3. It has expanded to 0.18 degrees by Nov 6, which estimates to 780,000 kilometers in diameter. It is therefore expanding at a velocity of about 300 meters per second.

My estimates seem a little high - I've heard in the last day or so anecdotal assertions of "the size of Jupiter", which would be only about 140,000 kilometers. Maybe I'm seeing more of the dust cloud than I think I'm seeing, but the calculations seem correct.

UPDATE: I've seen several estimates of "hundreds of thousands of miles in diameter", so that fits reasonably well with mine. The ambiguity has to do with where you cut off the size - at the dust cloud? Or at the halo (which can't be seen in my photographs).

More pages of photos have been added to the gallery. Take a look especially at pages 9 and 10. There are some wonderful photos of the emerging tail, and much better photographic evidence of the continued evolution of this comet in the last few days. Some of the photos are quite artistically nice, too.

Monday: 5 November 2007

Wasps and Sunflowers in November  -  @ 06:23:55
For the last few days and certainly through today, we've been at a Class 5 fire danger alert. Temperatures have been high, for early November, peaking today in the mid-70s, and there are winds. The absence of rain plays a part, of course, and the humidity in the afternoons has been down around 20-30%. We had no sooner finished the business meeting on Thursday night and arrived home when there was a fire pageout for Wolfskin, for a fully involved vehicle fire. It was an easily controlled situation but there were some safety and operational issues that should be addressed.

Closer to home, there have been some late summer-early autumn flowering plants but even the goldenrods and asters have been sparse and short-lived. In the early summer I planted a number of large pots with a number of species of natives just to see what would happen. We were able to keep these conservatively watered, and have been rewarded with periodic flowerings.

Right now, numerous individuals of a very nice wasp species (I'm guessing) are enjoying the Helianthus porteri, Porter's Sunflower (aka, Stone Mountain Daisy). This is a species USDA Plants targets for AL, GA, SC, and NC, so it's fairly localized and also prefers a rather odd environment: granite outcrops. Glenn "discovered" it a coupla years ago growing around granite outcrops along the Oconee River Greenway, and we've been trying to propagate it. It's an annual, and so has the dual characteristics of being fortunately robust and fast-growing, and unfortunately totally dependent on seed production, which is why you shouldn't be picking its flowers.

Here's the hymenopteran amid the ray and disk flowers of the sunflower:

I'm guessing it's a tiphiid wasp, possibly Paratiphia robusta, although Bugguide warns that no key is available and so species identification is difficult. Not that I'd be seriously attempting a key, but I did go through my Peterson Insects guide and can at least rationalize away the possibility of it being a scoliid wasp. Scoliids have the outer wing areas wrinkled, rather than in discrete veins and closed cells, as is clear from the first thumbnail below. The abdominal banding and shape and general hairiness seems about right.

The other characteristics seem right - the adults are flower nectar feeders. The larvae parasitize "white grubs", according to Peterson. If so, it's a new wasp for me, and of particular interest in that I'm seeing it in November, a late date pollinator.

Saturday: 3 November 2007

Comet Holmes  -  @ 05:40:17
Yesterday my parents reminded me that I needed to get out and attempt a little non-telescopic photography of Comet 17P/Holmes in the northern sky. So that's how I spent my 3AM this morning!

I actually began this around 9pm last night, but Perseus, the constellation which brackets the comet currently, had not yet risen above the trees. I took a few shots, of which this is one, to zero in on reasonable exposure settings. The comet is nicely visible as a globe in center, just at 7 o'clock from the concentration of stars that is Perseus. This photograph is considerably tweaked for brightness, contrast, effect, and fun (though nothing was added), unlike the ones below which were left untouched:

I went back in to do a few things and wait for Perseus to rise, a watched Perseus never rises, but by 11pm the clouds moved in so I went to bed. (Did the clouds bring rain? Uh, no. None in the forecast for the next week, at least. They were just there to annoy me.)

On October 24, over a period of several hours, Comet Holmes did the thing that tickles all skywatchers and astronomers - it brightened over a million-fold. Even now, ten days later, it's at least a half-million times brighter than predicted - easily magnitude 3 over the magnitude 17 expected. There's a very nice essay on the event here.

Comet Holmes is an easily visible object, as bright as any star right now, and is very nice in binocs where its diameter is easily apparent as it has expanded over the last week or so. Get out there and see it, and watch nightly to see what it does. While you're at it - look for red Mars, now as bright as anything else in the night sky, and directly overhead (from my latitude), smack in the middle of Gemini, at 5AM. Earlier in the evening it will be increasingly toward the east, of course.

So I got up at the usual time, 3AM, and checked again for clear skies.

For what it's worth, here's my photograph of a portion of the northwestern night sky including the constellation Perseus and the bright fuzzy globular apparition of Comet Holmes about halfway right of center (image links to larger). The photograph was taken with a tripod-mounted telephoto at minimal extension, f/5.6, 15 seconds, ISO 800.

I fully extended the telephoto to capture this enlargement (again, image links to larger version), same conditions. Holmes has not developed much, if any, of a tail (or perhaps it's pointed away from us), but it may yet hold more surprises. Actually it's not so shabby a photograph. In the larger link you can see the inner core and the dust cloud that's been expanding since whatever catastrophic event occurred ten days ago. The green tinge is much more evident as a large surrounding carbon monoxide halo in some of the fine photos in the Spaceweather gallery I link to below.

You'll find tons of sky maps directing you to Comet Holmes, so you don't have to rely on my version. If you're observing in the evening, Perseus is far enough up the northeastern sky to be manageable by 10 or 11pm. If you're an early morning person, say 3AM, situated around 34 degrees north latitude like I am, look north northwest and about 3/4 to the top of the sky. That's where you'll find Perseus, and in the middle of the constellation is Comet Holmes:

Don't imagine that comets are rare in the night sky. There are hundreds of them circulating through the inner solar system. The vast majority is just very very faint, seen only with very good telescopes. That one should suddenly, unpredictably flare into brilliance is a real treat. Here's what's known to be out there now - I count at least a hundred comets in the sky above my circular horizon:

And there are billions more far far up in the Oort Cloud, waiting for that little nudge that pushes them off their perches to descend to the warm fires like a fallen angel. has (at this time) eight pages of galleried photographs, beginning Oct 24. Don't miss the animations and nightly comparisons to be found currently on Page 7. And Page 8 has some beautifully imaged photographs of the comet, now clearly an emerald green in color.

Friday: 2 November 2007

The Month of October  -  @ 07:42:44
Here's the monthly summary of the climate of the month of October, here in Athens and US-wide. Our October was unusually warm and dry, but what else is new? How was yours?

For Athens, October continued the hotter than normal weather, 3.6 deg higher than average for October. We broke a record high on Oct 8, with 92 degF.

From the National Weather Service Climate Prediction Center, this is a plot of mean temperature anomalies for the US. That's the difference in the average temperature for this October above or below the average for October over many years, plotted in colors. The anomalies are in Fahrenheit.

Most of the country east of the Rockies was warmer than normal, with the northeast US experiening 6-8 deg warmer weather. The Pacific Northwest was 2-4 degF cooler than normal, as it was for August and September, too.

From the National Weather Service Climate Prediction Center, this is a plot of mean precipitation anomalies for the US:

Rainfall was abundant in scattered areas, but much of the southern half of the country received half or less the expected rain for October, with the exception of Florida and the Gulf Coast. In addition to the cool temperatures, the northwestern tier of states received copious quantitites of rain, as did much of the northern midwest.

It's instructive to look at the 365-day accumulation of rain. In this plot, much of the variation disappears, leaving only the areas that have experienced continuous extremes. The southwest and southeast US show more graphically what we've all known for awhile.

For Athens:

Here is my plot of high temperatures for the month of October in Athens. As usual, the black dots are for the 15 years 1990-2005 (black dots), 2007 (green line), and 2006 (red line).

There were 11 days in October at least one standard deviation above the 17-year average for that day. We used to consider that astonishing, since there are normally only 4.7 days significantly above average in October, but after August and September nothing is surprising. Even our nights were generally warmer, with only 2 much cooler nights when the lows were at least one standard deviation before the average low.

Here is the plot for our monthly accumulation of rain here in Athens for the month of October. The red line is the average over the last 18 years of September, and the river of peach defines the standard deviation range. Blue areas would mean significantly above-average if there were any, but that's a laugh. Mustard areas are significantly below. Athens claimed 2.35 inches of rain but out here we only got 1.4 inches, compared to the normal 3.0 inches of rain. We managed to stay within the peach region, but then again October has the highest variation of any month, along with the (usually) lowest amount of rainfall.

Of course, the rainfall accumulation for the full year is important, so here it is. We are now two standard deviations below normal for the year to date, and have received onl 57% the average rainfall over the entire year. And this is our dry season. As of the end of October there is only one year in the past 88 that shows just a slightly less accumulation of rain for the year: in 1981 at this time we had had 23.5 inches, compared to 23.7 inches this year. And 1981 was not preceded by another year of drought as we have been 2006-2007. This is clearly an exceptional, 100-year drought.

I should again link to this neat prognosticator in which you can get variously timed precipitation and temperature outlooks.

You might have heard that the states of Florida, Alabama, and Georgia are in acrimonious dispute over water rights, especially to the Chattahoochee River. The Lake Lanier reservoir, northeast of Atlanta, is formed by the damming of this river and supplies much of Atlanta's overused water supply. The Georgia governor is suing the Army Corps of Engineers for releasing too much water out of this reservoir.

Alabama came up with an interesting, rather elegant observation: they will no longer be able to sustain their nuclear power plant if water levels go too low. Considering the prevailing winds generally come from the west, it behooves Georgia to keep those water levels high! Clever!

NOAA's weekly ENSO update: This is the fourth month of La Niña conditions in the Pacific, and NOAA expects a weak to moderate event for the next several months. That means a warmer and drier winter in the southeast. Go to the La Niña Extreme Event Risk figure to see what it might mean for you.

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