Newsgroups: lter.ced Path: LTERnet!news From: "Bruce P. Hayden" Subject: CED 2.2 Message-ID: <1993Feb23.175352.22923@lternet.washington.edu> Sender: news@lternet.washington.edu Organization: Long Term Ecological Research Date: Tue, 23 Feb 1993 16:42:18 GMT ***************************************************************** ***************************************************************** *** *** *** *********** *********** ********** *** *** * * * * *** *** * * * * *** *** * * * * *** *** * ********* * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** *********** *********** ********** *** *** *** ***************************************************************** ***************************************************************** Vol.2 No.2 :::::: file name:CED2.2 :::::: March 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 Daniel Pommert [daniel@lternet.washington.edu] by the file name given in the masthead. Daniel can also add people to the CED mailing list. 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. ***************************************************************** ***************************************************************** *** *** *** *** *** RISSER COMMITTEE MEMORIAL EDITION *** *** *** *** *** ***************************************************************** ***************************************************************** The Risser Committee report on the first 10 years of LTER and CED 2.2 have one thing in common. They are both due on 1 March 1992. If you find some shortcomings in this issue of CED, you can at least hope for longcomings in the VCR response to Risser questions. See you all in Oxford, Ohio. Administrative news -- CED subscription is managed by the LTER Network Office. They can add or remove e-mail addresses. So, what if you have to have a look at a back issue of CED. For shame, you didn't harvest a copy for your files. Or, you sent your copies off to the bindery for hardback storage. How do you meet your need to have a peak at the coveted back issue? Log on to your local GOPHER. In the OTHER GOPHERS line in the menu, you can call up the Virginia Coast Reserve LTER GOPHER (VCRIS) and hunt away until you find CED. In your search you will see the LTER Network GOPHER, the Hubbard Brook GOPHER, the Cedar Creek GOPHER and the VCR GOPHER. Watch for the LTER Data Managers Group's publication on a GOPHER at your site. WARNING -- GOPHERs need to be fed! ***************************************************************** ***************************************************************** *** *** *** *** *** FEVERISH ON BORE HOLES *** *** *** *** *** ***************************************************************** ***************************************************************** When Gaius Shaver was known as Doc Savage, CED 1.7, we were feverish on bore hole temperatures. Bore holes bored down through the otherwise boring earth may reveal past average surface temperatures. In CED 1.7 we related Shaver's recounting of bore hole temperatures near Dead Horse, Alaska, aka, oil wells. The notion was that North Slope warming this century had been detected and that readers of Science magazine had the right to know about it. We also reported on a Cuban bore hole. Boring? No, deforestation and sugar cane farming, in pre- pre-Castro days, were seen in the temperature change with depth. Now, out of the woodwork, comes an entire journal dedicated to bore hole climate records. The journal is a spin-off journal of PPP, aka, Paleoclimate, Paleoecology, Paleohydrology. The spin-off's name is Global Planetary Change. So drift on by your local science library and pick up the last issue of 1992 and have a look. There is even an article on how you take the raw bore hole temperatures and filter, message and transform it into a smooth temperature curve. Here is a CED sketch of what they look like. I have put time on the y-axis because it is easier to make an e-mail graph with singular values in the up-down direction. ___________________________________________ 0 AD | o | o 100 | o | o 200 | o | o 300 | o | o 400 | o | o 500 | o | o 600 | o | o 700 | o | o 800 | o | o 900 | o | o 1000 | o | o 1100 | o | o 1200 | o | o 1300 | o | o 1400 | o | o 1500 | o | o 1600 | o | o 1700 | o | o 1800 | o | o 1900 | o | o 2000 |_________________?o?________________________ TEMPERATURE Pretend this is a dot-to-dot picture and connect the dots with a nice magic marker. Now that looks good. In looking over all the graphs in the journal I think the time-temperature histories are pretty good back to about 1300 AD. Before 1300 AD, I see differences in the bore hole temperatures with known paleoclimate variations in temperature. Putting the coldest of the little ice age at 1800 is not bad but there are other records that put it in the early 1700s. The sharp rise from 1800 to 1900 looks pretty good. In the post-1900 period, the records are problematic because of surface thermal variability at this close distance to the surface. In my view, the most interesting stuff is on vegetation change and bore hole temperatures. The equilibrium bore-hole temperature difference between forest and grassland, at the same general location, is on the order of 4 to 5 C. The implication is clear. Cut down the forest and temperatures rise 4 to 5 C. That is bigger than what most of the GCMs say will happen with a doubling of CO2! Now that is newsworthy. These days at global climate change workshops, there is some crusty non-fool who says that landscape and landcover changes will be bigger than CO2 global warming. What happens to one of our weather stations when the landscape changes from forest to fields or suburbs? Yes, the "climate" of the station changes and the changes are bigger than urban warming. The surface record of thermometric measurements is a most difficult record to read. I think the best of the records is NCDCs US historical station network (some 100 nice, rural stations). NCDC is working on a global historical station network. Watch for it at your local data store. They have worked mostly on getting rid of stations that might have urban warming, stations that have had vegetation changes around them, and the stations that have been moved. Many stations were moved to airports in the 1940s and 1950s. What Harvard Forest needs is a good bore ...... hole! They have a wonderful history of vegetation change. Wouldn't it be nice to have a bore-hole- temperature record for the site. ***************************************************************** ***************************************************************** *** *** *** *** *** VEGETATION ON LIGHTNING; LIGHTNING ON VEGETATION *** *** *** *** *** ***************************************************************** ***************************************************************** Over the 70% of the earth with no leafy vegetation, lightning is very rare. In the 30% of the world with leafy vegetation, your land and mine, you have good prospects of lightning. Chance? No connection? Hey, what's up? Well, there are lots of big-time convective clouds over the oceans, especially over the oceans with warm water. Convective clouds of similar size over the land can lash the landscape with bolt after bolt of lightning. Oceanic convective clouds are electric wimps! I have talked with many meteorologists who have spent time at sea. They assure me that lightning is pretty rare at sea and that the further from land the less likely to run into one of Thor's thunderbolts! Ben Franklin would have been much safer flying his kite and key from the deck of one of the ships he took to sojourn at the courts of Europe. In those marine areas, where sometimes lightning is seen and thunder heard, you are most likely down wind from a continent or there are vegetated islands of some size or number near by. Convective clouds at sea and on land are characterized by upward motions inside the clouds. When you see the billowing cauliflower heads on convective clouds growing upward, you see evidence of these upward motions. Upward motions in oceanic convective clouds are about half the velocity of those of the same size over the land. Meteorologists put these slow-poke motions as the cause for the failure to produce lightning. The anti-correlation between lightning strokes and low-upward-motion clouds is difficult to prove. So, I will ask the silly question. Now you know what I am getting at. Vegetation might be responsible, contribute to or play a role in lightning. Boulder-dash! Poppy-cock! No way Jose! News flash--Hayden goes bonkers! Well, I think there are several cases to be made, so here goes. ***************************************************************** ***************************************************************** *** *** *** *** *** DEVIANT PROFESSOR WENT *** *** *** *** *** ***************************************************************** ***************************************************************** Well, the full credit for this deviant thinking must be traced back to a Botanist named Fritz Went. He published his vegetation makes the lightning go theory in the Proceedings of the National Academy in 1967. CED readers will remember that decomposition of plant litter produces ice nuclei that cause ice to form in clouds at temperatures much warmer than would otherwise occur. When you get ice in clouds the rate of deposition of water vapor to the frozen drops is much faster and the rate of release of latent heat is greater. The air gets warmer. It is more buoyant and lifts faster than it would if the drops had not frozen. If things are just right, the air becomes auto-convective. Lifting air supports more lifting. That is just the thing to make convective clouds grow upward faster. There is no source of ice nuclei over the oceans that make ice at warm temperatures. Sea salts cause cloud drops to freeze somewhere around -25 C. Not much help. Good old CPR ice nuclei would cause freezing between -8 and -14 C. Out there in the prairies you can get a convective storm growing fast. Wonderful lightning bolts. Crash-bang weather. Nothing like it over the oceans. Sagebrush litter decomposes to produce ice nuclei that cause ice to form around 12 C. Not bad. So, that covers one way that vegetation may play a part in lightning. It can help promote faster upward velocities in convective clouds. Islands in the oceans produce some ice nuclei. Winds blowing off the continents provide a terrestrial source of ice nuclei. Just off shore, in the downwind direction, you get some, not much but a bit, of lightning at sea. Went did not propose that vegetation might foster upward growth and so make terrestrial convective systems electric. That is my idea. His model proposed that vegetation was the source of + charges in the air and - charges at the surface. To get lightning you need to provide charges in the clouds and get the positive and negative charges in different parts of the cloud and then let the sparks fly. Well, where do charges come from. Radon in the earth emits alpha particles and with decay giving a + electric charges to the air. Breaking waves produce some charges as the water drops are torn apart as the waves break. Sharp points like pine needles produce some charges. Terpines and hemiterpines produced by vegetation end up producing a net positive charge on the agglomerated spheres of terpine molecules. Most meteorologists think that the charges arise from rain drops in clouds that break apart and the two parts have one a plus charge and the other a minus charge. To the weather geeks all the charge is produced in the clouds with no help from the green stuff. Production of charge from the ground is less well studied or worried about anymore. I have been talking about this with my meteorological friends and they are as they should be skeptical but by no means discouraging. To them it is a hypothesis to study. I given them the papers they had not seen before and let the stuff rattle around their heads. Right now they are saying -- yes it is possible. It explains observations. Pretty good when it comes to hypotheses. So to CED readers have a look at the ideas and hack away at them. Consider it recreational study. There is probably no research money in it so you need to do it on your own time. Live it up. ***************************************************************** ***************************************************************** *** *** *** *** *** WENT WENT FURTHER *** *** *** *** *** ***************************************************************** ***************************************************************** Went went a bit further. Well, Went went a lot further. He suggested that the dark and foreboding clouds about to discharge on passing golfers are dark and foreboding because the biogenic hydrocarbons that brought the charge when incorporated in the clouds. Black clouds due to hydrocarbons? Boulder-dash! Poppy-cock! No way Jose! News flash--Went went bonkers! Well, Went is dead so I will have to be bonkers for him. In my travels over the tropical ocean blue, the cumulus clouds at distance were brilliant white. Well, there are sort of gray or silver on the bottom of the cloud and on the side away from the sun (your run-of-the-mill silver lining). My travels over the grass oceans of the West and mid-West imprinted the specter of dark and foreboding cumulus clouds. From my porch in Virginia, with very few cumulus clouds from the ocean direction, my clouds are on the black side even on the side with the sun shinning on it! This next year I am going to become a serious watcher of clouds to expand my observational base. For now I can hit the books! The best book for this kind of stuff is M. Minnaert's The Nature of Light & Color in the Open Air. With a title like that it must be a book of some antiquity. Right on. 1954. My copy is a Dover (love that publisher) reprint of an English translation from the 1930s original French edition. The book informs and entertains you on mirages, haloes, shadows, double rainbows and hundreds of other things you may see in the open air with the naked eye. I can relate the flavor of the book to you with a couple of his topic sentences: "The beam of a searchlight furnishes matter for various interesting observations" and "It is worth while during a shower to observe in which direction the falling rain is most easily seen." Now that is the stuff of a real selling card. Get your Dover catalog and outfit your bookshelf with a copy of Minnaert's little gem. Minnaert has a nice section on "The Colour of Clouds." He begins, "It is a pleasure to watch the beautiful summery cumulus clouds drifting past, and to try to account for the fact that certain parts are light and others darker." Just what we need. He notes that the drops in the cloud back scatter the light in the direction of the sun and so the bottom of the clouds and the side away from the sun are in the shadow of the cloud above. He notes that this helps in the explanation a lot but doesn't explain all the differences in cloud color or colour. Get this one. "If, when the weather is clearing up after a storm, only a few small cumuli are left, brilliantly illuminated by the sun, with no possibility of one casting its shadow on another, they grow darker and darker and finally blue-black when they are about to disappear." Wow, that is heavy. He doesn't have an explanation for this little observation. But, he concludes by saying that we must consider the "possibility of their containing dark dust-particles as well." Dirty clouds! Maybe Went's hydrocarbons in the air. In the 1960s passenger planes filtered incoming air and the filters were black with a hydrocarbon, tar like mess. Went went to the airlines to get the filters and check it out! Back then it did't take, nor did the know much about, a rocket scientist ..... Minnaert pleads with the reader to investigate why rain-clouds are so gray and thunder clouds so leaden in color. He worries that it is in dust. Dirty clouds. Well, it is still the meteorologists dirty little secret that nobody seems to know for sure. Well, we are left with more questions than answers this time. Here are some rules of thumb that you need to keep in mind. Thunder and lightning storms are most common in maritime tropical air and over land with a high primary productivity! Out west, cool marine air comes ashore on its way east. Lightning is not common over the coast ranges; it is more common over the Cascades; and, it is still more common still by the time it reaches the Rockies. Are the plants loading it up with charge and hydrocarbons, and condensation nuclei, and or ice nuclei, and after sufficient accumulation lightning bolts rain down! ***************************************************************** ***************************************************************** *** *** *** *** *** BLACK SNOW *** *** *** *** *** ***************************************************************** ***************************************************************** Be honest. You've seen black snow flakes falling. You also know that, in my quest to understand the atmosphere in terms of the biosphere, I have implicated the kind of ice nuclei produced by decomposing vegetation in the kinds of flakes you are likely to get. Unfortunately, black snow flakes are not flakes made dirty by biogenic hydrocarbons. You see black snowflakes against a gray sky. Black, gray and white differ in their brightness, for which the surrounding background provides the standard of comparison. When the snow is falling the flakes have less light on them than the cloud does from the sun atop. The sky is brighter than the flakes below and so the flakes appear gray or even black. We can attribute this explanation to Aristotle. ***************************************************************** ***************************************************************** *** *** *** *** *** SLIP OF THE SUCKING MOUTH PARTS *** *** *** *** *** ***************************************************************** ***************************************************************** A CED reader in Montana thinks it is good I got out of physiological ecology for "something more interesting." (see CED 2.1) My angst at the end of my aphid piece had merit. Aphids suck phloem not xylem and so passing clouds and fluctuations in water potential doesn't matter. And besides phloem is under positive pressure and gray skies or not, the juices just keep roaring into the sucking little critters. You can hardly call that sucking. It is more like putting your lips on a Texas gusher. Sorry, Montana. Anybody around who knows of a good xylem sucker? ----------------+--------------------------------+------------------------- 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) ----------------+--------------------------------+-------------------------