Newsgroups: lter.ced Path: LTERnet!news From: "Bruce P. Hayden" Subject: April 1 CED Message-ID: <1993Mar30.160437.1268@lternet.washington.edu> Sender: news@lternet.washington.edu Organization: Long Term Ecological Research Date: Tue, 30 Mar 1993 14:49:54 GMT ***************************************************************** ***************************************************************** *** *** *** *********** *********** ********** *** *** * * * * *** *** * * * * *** *** * * * * *** *** * ********* * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** *********** *********** ********** *** *** *** ***************************************************************** ***************************************************************** Vol. 2 No. 3 :::::: file name: CED 2.3 :::::: April 1, 1993 ***************************************************************** ***************************************************************** CED is the Climate/Ecosystem Dynamics bulletin board of the LTER network. In CED you will find exchanges of ideas, information, data, bibliographies, literature discussions and a place to get to experts within the LTER community. We are interested in both climate controls on ecosystems and ecosystem controls on climate. As this is an inter-disciplinary activity, we hope to provide things that you might not come across in your work at your LTER site. CED is a product of the LTER climate committee and contributions to CED for general e-mail release may be sent to either David Greenland of Andrews LTER [Greenlan@oregon.uoregon.edu] or to Bruce Hayden of the Virginia Coast Reserve LTER [bph@envsci.evsc.virginia.edu]. We expect that the scope of CED will evolve and reflect the interests of the contributors and users of this service. CED will be issued as the preparation work gets done (monthly?). Back-releases of CED may be requested from Hayden by the file name given in the masthead. Feedback on CED from LTER scientists is welcome (non-$$$$ contributions also welcome.) For example, please forward citations of climate & ecosystem publications on your site. We will keep a LTER wide bibliography on Climate/Ecosystem Dynamics that we pass on via E-mail. CED is on the network office GOPHER and on the VCR GOPHER and can be found from any GOPHER anywhere in the world. ***************************************************************** ***************************************************************** *** *** *** *** *** COWEETA SNOWED BY GLOBAL WARMING *** *** *** *** *** ***************************************************************** ***************************************************************** DATELINE Coweeta, North Carolina. AGENT: L. Swift. We must do something about this GLOBAL WARMING! A record 643 mm of GLOBAL WARMING is a bit excessive. We had so much WARMING that we did not need electric power from 0150 Saturday morning until 1745 Tuesday. Some communities waited until the next Sunday for power. The WARMING killed our tropical fish and our confused dog wandered off looking for a patch of grass and has not returned, presumably dead in a drift of GLOBAL WARMING. Air temperatures during the GLOBAL WARMING event reached -18C and several cattle barons have hired back-hoes to bury animals killed by the heat-wave. As predicted by the scare-press, forests were decimated by the GLOBAL WARMING, mainly by the weight of the WARMTH in pine crowns followed by high winds. Fodder for the biomass folks. ******************* Charlottesville, VA. When I got this nice missive from Lloyd I felt tempted to dash of a note to him that the a clever climatologist could make the case for blizzard-level snowstorms in a warmed-world. But, because the warmed-world wonkies work so hard to weave every heat spell, drought and bad case of acne to the global warming story, I just thought I would let people stew for a while in the crock-pot of wondering how wonderful snowflalls in a CO2 rich world could really happen! ***************************************************************** ***************************************************************** *** *** *** *** *** VOLATILES AND THE VOLOLOGIST *** *** *** *** *** ***************************************************************** ***************************************************************** Say Bruce, I'm not a climatologist, ecosystemologist, or borologist, but I do get a kick out of CED. Learn more there, than anywhere else on the net, however, could you explain how decaying plant matter creates ice nuclei. And why would sage brush produce such nuclei at 12C? I've never seen a frosted decaying sage at anything significantly above zip C. Maybe in your next installment you could elaborate just a tad more on this. I may be the only volologist out there reading CED, but I bet there are a few more 'ologists that could use some insight. The literature (Vali et al., 1976. Biogenic Ice Nuclei. Part II: Bacterial Sources. J. of Atm. Sci. 33:1565-1570) indicates that the decomposition organisms are neither voles nor sage. I know of no studies on ice nuclei made from the carcasses of anything higher on the trophic levels than green stuff. Probably bacteria in most cases. They take the organic matter, have their way with it and leave behind organic molecules that have the property of bringing on ice-crystal formation in supercooled water (temperatures < 0 C). Supercooled water is found in atmospheric water drops and probably in xylem water at times. Not all bacteria have the capacity of make ice nuclei. Most tested thus far do not. Pseudomonas syringae does a great job of ice nuclei synthesis. P. syringae and an encoded-fellow named C-9 was isolated from a laboratory leaf slurry. P. syringae could make supercooled water to freeze at the very warm temperature of -2.6 C. All of the other bacteria isolated from the slurry, tested one by one, failed in ice nucleation graduate record exams. Seven other laboratory species of Pseudomonas were tried and all flunked out. Fungi in the slurry couldn't cut the ice either. Only aerobic bacteria seem up to the job. What ever the material is that does the ice-making job, it is heat-labile. 65 C for 5 minutes and the ice-making property is gone. Killed bacteria did not diminish the activity suggesting that the bacterial cell walls might be implicated. Pseudomonas syringae grown in the microbiologist normal witches-brews also produces the ice nuclei. On the other side, plant terpines act as ice nuclei (Rosinski and Parungo. 1966. J. of Appl. Meteor. 5:119-123.) Ice nuclei are about 0.1 micron in size. Stuff in the air that scatters light in the blue is of this size. Schnell and Vali (1976. J. Atm. Sci. 33:1554-1564) indicate that the ice nuclei may be potassium and magnesium organi-metallic chelate compounds with a high proportion of carbon, hydrogen and oxygen atoms. Now I don't know why bacteria do this for us. What is in it for them? I have tried to figure out what value is returned to the bacterium. Ice nuclei generating bacteria of various climate zones produce ice nuclei that cause freezing at different temperatures. Tropical bacteria produce ice nuclei that cause ice to form at very cold temperatures (-20 to -25 C). As you go to higher latitudes the bacteria produce ice nuclei that make ice at warmer temperatures. There seems to have been a latitude dependent selection for bacterial genes that render bacteria able to produce the right kind of ice nuclei for that climate zone. Then again it could be just another case of nature by chance. The first case I found of an organism with ice-making equipment that could be offered up as selfish was the desert lichen that I reported on in an earlier CED. In the desert, ice making means water collecting from the vapor in the air seems like a fine thing for desert lichen to have. There is no indication that bacteria work with the desert-lichen marriage of algae and fungi but what a harmonious trio it would be! This is the stuff of introductory textbooks. Why would these microbial critters make ice nuclei that worked at different temperatures. Give the bacteria free will and the ability to control their own biochemical mechanisms. Now you put forward the notion that making it rain is a selfish, value-returning activity for the bacterium as they need water to run their business. Well, why not just make ice nuclei that could make drops of water freeze at exactly 0 C? In the low latitudes, clouds would not get very tall (they don't grow much taller when all the drops are converted to ice) and drops would not grow very big and it would be hard to get it to rain. With very cold temperature ice-nuclei, the clouds get grow tall before all the drops have turned to ice. Big drops and high rainfall intensity is the rule and torrential tropical rainfalls the result. In the higher latitudes, ice formation in drops takes place at warmer freezing temperatures. The clouds in the high latitudes don't get as tall as they do over the Amazon for example. The height of big thunderstorms is about the top of the troposphere. On occasion they break through and rise into the stratosphere and add water there. But we can use the top of the tropopause as the top of the convective mixing layer. The tropopause is at about 18 km in the tropics and 11 km in the high latitudes in summer. What role is played by the bacteria in keeping this geography of the thickness of the troposphere the norm. Ice nuclei are generally rare in the marine atmosphere except where very high oceanic primary production is found (see Schnell and Vali, 1976). Ice nuclei from sea water are larger than from terrestrial sources (1 micron v 0.1 microns). They are heat labile at 100 C. Laboratory grown plankton produce ice nuclei with freezing at -2.8 C. Oceanic bacteria could be involved decomposing phytoplankton and producing ice-nuclei in the process. Schnell and Vali find that marine ice nuclei are in low concentrations in the warm tropical and subtropical oceans and are greatest just poleward of the subtropical convergence zone around 40S. Cold, rich waters are where the action is. ***************************************************************** ***************************************************************** *** *** *** *** *** MICROBIAL CLOUDS *** *** *** *** *** ***************************************************************** ***************************************************************** The time seems right to quote Gregory (1967) Atmospheric microbial cloud systems. Sci. Progr. Oxford, 55:613-628. The microbial cloud system "contains vegetative cells of protozoa, bacteria, fungi, mosses, ferns, . . . this microbial soup bathes man, animals and crops for good or ill." It is sad that Gregory didn't know of the role that microbes might play in cloud physics and the dynamics of precipitation processes. In 1957 Soulage (Ann. Geophys. 13:103-134) found microbes at the centers of artificially grown snow crystals and suggested that they serve as ice nuclei. ***************************************************************** ***************************************************************** *** *** *** *** *** THE COLOR GREEN *** *** *** *** *** ***************************************************************** ***************************************************************** Indy Burke (CPR) has passed on a couple of the CED flashes, and they're great! Could you add me to the distribution list? -- One cloud color point worth mentioning--green. I've seen only two really green and dark clouds (the bulk of the cloud is dark, but the green is almost luminescent)--one preceded a tornado funnel in Ohio, and the other preceded a 7 cm storm (in 20 minutes) here in Ft. Collins. Perhaps extreme events depend upon high concentrations of plant derived compounds (chlorophyll?)... ****************** This was a bit of fun for me. I searched my memory banks for green clouds and remembered only one occasion. I headed up-elevation from Ft. Collins then north and down toward Cheyenne. A great thunderstorm was just east of Cheyenne; the base of the cloud was greenish the rest rather black. When I got the e-mail response to CED 2.2 on green clouds, I didn't have an answer to the green mean clouds. So, I went to the books and asked around. I hit paydirt with a colleague, Bob Davis, who took an atmospheric optics at Penn State more than 10 years ago. He saved his class notes. I like a guy like that. The Prof. in this class would show slides of atmospheric optical phenomena and explain the physics. When test time came he would show slides say "What's going on here?" and wait 3 minutes and show the next exam slide. It sounds just like art appreciation and music appreciation courses the jocks all took! Anyway here is the skinny on green, mean clouds. 1. The sun angle must be low. This gives a long path length for light scattering. 2. The sun is in front of you; so, the light that reaches your eyes is by forward scattering (it is brighter than back-scattering (see the piece on mature manure mists below). 3. There must be lots of haze size particles in the air (the size that scatters in the blue: e.g. biogenic hydrocarbons). 4. The mean cloud is a collector of the air from near surface that is filled with the biogenic hydrocarbons. If these particles are lifted well up into the clouds, water condenses on their surfaces and rain drops are formed. If they are delivered downward in down drafts around the margins of the cloud then the drops are evaporated and dried out and the small blue-scattering sized particles are returned. 5. The blue wavelengths are scatterers to a maximum so in the direction of the sun the green wavelengths get through to your eye and you see green and are overcome by the kind of jealousy that comes when somebody has already figured it all out and you are a Johnny-come-lately! It is not chlorophyll that makes the mean cloud green but probably the terpines and hemiterpines that are made early in stages of photosynthetic carbon fixating and can scatter away all the blue light. Now for non-mean green clouds. Minnart (see CED 2.2) reports observations of green clouds (only a few hundred meters above the ocean surface) over the Indian Ocean where there was a scattering and reflection from a phytoplankton bloom. Optics again and sometimes you just can't keep the biota out of the story even if your try. This is a similar to the famous navigation trick by Scandinavian sailors. In ice bound waters they would sail in the directions of the clouds with the dark bottoms and not in the direction of those with bright bottoms. In this case the strong reflection of light from the ice surface made cloud bottoms bright while the clouds over open water got little light reflection from the ocean surface. ***************************************************************** ***************************************************************** *** *** *** *** *** MATURE MANURE MISTS *** *** *** *** *** ***************************************************************** ***************************************************************** Some things are just fun to tell. So, here is another forward light scattering piece. I'll start with a question. Why is the morning mist that rises from a good microbially-cooking, mature manure-pile more vigorous when viewed from the shady side of the manure pile than from the sunny side of that early-morning dung-heap? Clues are in the green cloud story. Forward scattered of light is brighter than back scattered light. In forward scattering, the light waves remain in phase after the scattering. In back scattering, the waves of photons are at a wide range of phases. Interference cancels out some of the light and it is all rather dim. So, we have the rising, ripe mist of sweet smelling scents coming from the putrid pile of piloblis substate for all to see. It is a place you can get in touch with your feelings. The mist scatters the light and we see it as a diaphanous mist. If it didn't scatter the light (remember it scatters all wavelengths because the mist drops are big relative unlike blue scattering haze particles) the emanations from the pile would be transparent and I would never have needed to talk about all this. To get yourself all squared-away on brightness of light scattering try the following. Wait until summer comes and it is about one hour after sunrise. By that time turpines and hemiturpines are fresh from the early morning photosynthesis and a blue haze of the early day begins to develop. Look toward the sun and see how bright the haze is in the forward scattering direction. Now put on your tutu on, begin a slow pirouette and notice that the haze is least bright when the sun is at your back and the haze is seen only from backscatter. So, you want a real puzzle. Get your polarizing sunglasses on without getting out of your tutu and then do the same haze-viewing, slow pirouette. Is there any difference in the haze brightness by this new method? Biogenic haze when the relative humidity is less than 65% scatters and polarizes light. Now that is tutu much of a challenge for the curious scientist. ***************************************************************** ***************************************************************** *** *** *** *** *** WHO GETS THE SHOCK OF A LIFETIME *** *** *** *** *** ***************************************************************** ***************************************************************** Is seems that when you mention lightning it begets questions. Several messages came to my CED in-file. One asked if the old tune "Don't sit under the apple tree with anyone else but me..." had anything to do with the chances of a good lightning strike. Like lightning, this question just came out of the blue. I took to my private sources and could find nothing on apple trees as targets of Thor. For those of you who know a lot about beech and would be willing to stand under one in a thunderstorm, record your confidence of being hit as 1.0 then you could rate standing under a spruce at 6, a Scots pine as 37 and an oak as 60. This little ranking is from "Trees and Lightning," Royal Meteorological Society, Quarterly Journal, 33:74:1907. Carl Muller in little book Himmel and Erd, report that in 11 years of tabulating lightning strikes by species the following: 56 Oaks hit, 20 firs, 4 pines, but not a single beech was hit even though 70% the trees were beech! Oaks are favored over beech as the fall-guys in "Which Trees Attract Lightning?" (Monthly Weather Review, 26:257, 1898.) Other than a beech bullish article in the journal KNOWLEDGE (1914), the literature has been mum since. They really knew how to name journals in those days. In my reading on lightning strokes and trees I came across some 1860s work on heat conduction in trees. The claim was made that trees are poor conductors of heat in the radial direction and in the circumferential direction but pretty good in the up-trunk and down-trunk directions. My first thought was that the tracheid and vessels, filled with good heat conducting water, accounted for the observations. But the wood tested was dried cubes of wood! Now we are down to the cellulose polymers being vertical might be the route of the conducted heat. Well, this is just guessing and I am sure that the folks at NTL can trot down the street to the Wood Products Lab and find out the reasons for the observations. The question remains: is there any benefit to the trees from this partitioning of heat conduction in the x, y and z directions? Minimization of freezing and thawing damage in winter, perhaps. Once the wood gets cold and perhaps frozen inside, it stays that way and only thaws out slowly. You don't want a rapid thaw and expansion as the temperature passes through +4 C. ***************************************************************** ***************************************************************** *** *** *** *** *** CONICAL FLAKES AT THE RISSER MEETING *** *** *** *** *** ***************************************************************** ***************************************************************** Snowflakes have hit the pages of CED before and so I feel free to report that conical snowflakes were reported by LTER PIs at the now memorable Risser Committee meeting in Oxford, Ohio. Nice big flakes were there for our delight. These were actually pancake shaped collections of flakes. When the big flakes fall, their centers get a bit on the heavy side and sag down. The edges are lifted up as the air rushes by. These flakes were on the order of a cm or so across. During fall the edges pick up crystals and so the falling pancake of snow, conical and the snowflake gets bigger as it falls and collects more snow on its rim. An observer of days past, one Mr. E. A. Evans, published a little note in the April 1900 issue of Monthly Weather Review. I repeat it here to show that the Risser Committee experience could be outdone. "The morning of this date was cloudy, with a fresh, chilling, northeast wind. The temperature rose slowly during the forenoon, and at 1:17 p. m. a light rain began to fall. Soon sleet accompanied the rain, and later the rain ceased and sleet fell alone ... At 5:25 p.m. moist snow fell with sleet. At first the flakes were not large enough be be specially noticeable, but as the fall of sleet diminished in volume, which it immediately did, the flakes increased until they attained unusually large proportions. They were irregular shape, mostly oblong; several were seen the greatest diameter of which could hardly be covered by a teacup. Some were caught upon a piece of dry wood and examined. In every instance the center of the flakes were composed of a soft mass of snow about a half an inch in diameter, while the edges were thin, looking as though they might have been separate flakes which had attached themselves to the central mass while it was falling. The weight of the center being greater than that of the edges caused the larger ones to assume the form of an inverted cone falling, the outer edges being bent up by the resistance of the air. Three of the large flakes were caught in a bowl, yielding, when melted nearly a tablespoonful of water. There was nothing at hand from which an absolute measurement could be had, but it is estimated that it would have closely approximated one one-hundredth of an inch. The flakes were widely separated from one another and did not obscure the vision in looking upward towards the sky." Tea cup sized snowflakes remind me of the little poem that ends -- "thank the lord cows can't fly." ***************************************************************** ***************************************************************** *** *** *** *** *** POLAR COOLING! RUN FOR YOUR LIFE *** *** *** *** *** ***************************************************************** ***************************************************************** If Boris is still in office when you get this, the cold war is still history. The cold pole is still with us and getting colder. J. D. Kahl and a bunch of his friends tell all in Nature [1993. 361:335-337]. They got their hands on 27,000 B-52 drop-sondes taken between 1950 and 1990. Boy, I love that freedom of information stuff. Not only that but Ivan-in-uniform on ice islands in the Arctic sent up balloons twice a day to measure the usual weather stuff. For the 40 years Kahl finds 4.14 C cooling in the Autumn and 2.2 C cooling in the Winter and an annual average cooling of 1.47. Just when the polar regions should be warming rapidly we get fooled and find it is cooling rapidly. Not only that, but the the cooling is in the time of the year when the warming should be greatest. To quote one honey-loving bear, "Oh, bother!" And you thought that you were not getting your dollar value out of all those B-52, perpetual-alert SAC-flights. Shame on you. *********** CONCLUDING NOTE *********** There were no baseball caps worn by site-PIs at the Risser Committee meeting and so I could not confirm earlier CED data on pinheads and fatheads. Sorry! ----------------+--------------------------------+------------------------- Bruce P. Hayden | Dept. Environmental Sciences | bph@virginia.EDU (804) 924-0545 | Clark Hall, Univ. of Virginia | bph@virginia.BITNET (804) 924-7761 | Charlottesville, VA 22903 | (804) 982-2137(fax) ----------------+--------------------------------+-------------------------