Newsgroups: lter.ced Path: LTERnet!root From: bph@virginia.edu Subject: CED 2.7 End of July Message-ID: <1993Jul30.153229.15683@lternet.washington.edu> Sender: root@lternet.washington.edu (Operator) Organization: Long Term Ecological Research Date: Fri, 30 Jul 1993 15:00:23 GMT ***************************************************************** ***************************************************************** *** *** *** *********** *********** ********** *** *** * * * * *** *** * * * * *** *** * * * * *** *** * ********* * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** *********** *********** ********** *** *** *** ***************************************************************** ***************************************************************** Vol.2 No.7 :::::: file name:CED2.7 :::::: August 1, 1993 ***************************************************************** ***************************************************************** CED METADATA ---- 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 find 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 (usually monthly). Back-issus 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 are keeping a LTER wide bibliography on Climate/Ecosystem Dynamics that we pass on via E-mail. ***************************************************************** ***************************************************************** *** *** *** *** *** CED 2.7 AGAIN? *** *** *** *** *** ***************************************************************** ***************************************************************** Sharp-eyed, email-literate Lloyd Swift (Cowetta) sent the following. Bruce: Is it true that there is no CED2.6? ANSWER: No. It wasnt true. I had to write Lloyd and tell him that I skipped the number 2.6 for technical and stupidity reasons. The last issue was 2.6. Please take a crayon and cross out the 7 in 2.7 and make it 2.6. It was thrilling, however, to note that CED readers are so sharp. Thanks Lloyd! ***************************************************************** ***************************************************************** *** *** *** *** *** DISTURBANCE AT ALL SCIENTISTS MEETING *** *** *** *** *** ***************************************************************** ***************************************************************** Disturbance is, of course, a LTER core area. All LTER sites are engaged in studies of disturbance in or on ecosystems. And, we are holding a disturbance workshop at the All Scientists Meeting this fall. We = Fred Swanson, Dave Foster, Jerry Franklin and myself (Bruce Hayden). Break out your best disturbance stuff and bring it with you. I have taken the liberty focusing of this month's CED on disturbance. Hopefully, this contribution will help draw people to the workshop, get everyone thinking in new ways, and force us to consider a network wide synthesis. Now, that is a tall order but tall orders don't get to be person-sized until you begin to work on them. It is unfortuante that we no longer have the Big Rivers LTER in Illinois. Talk about disturbance! ***************************************************************** ***************************************************************** *** *** *** *** *** MISSISSIPPI FLOODS: NOAH or JOSEPH? *** *** *** *** *** ***************************************************************** ***************************************************************** The upper Mississippi usually wins its flood waters from the Spring melt of winter snows. The Spring flood is the collective product of many snowfalls over the span of the winter months. This year it was different, all different. Reports of the spring floods were restricted to the local tabloids. Dan Rather had to find other places to go in his reporter-khakis. Long after the winter's burden of Minnesota snows had passed New Orleans, the thunderstorm season began. Normally thunderstorms flood the tributaries of the tributaries and leave the mighty Mississippi muddier but not swollen. In 1993, we had a long run of big-time thunderstorm-systems residing in the basin of the Upper Mississippi. This was not a disturbance event but rather a long run of disturbance events. We need to distinguish between these two kinds of disturbance. On the upper Mississippi this year, persistence ruled the day and the day after and the days there-after. A rather winter-like trough in the jet stream was centered about 90 W with a companion tendening-to-stay-in-one-place ridge was over the Northern Rockies. The summer-typical westward and northward expansion of the North Atlantic Subtropical Anticyclone (the Bermuda High) was happily in place and persistently so. It was like a New Age harmonic convergence. Ideas about the ecological consequences of the Flood of 1993 are rumbling around academic places and research proposals are, no doubt, in the making. Rightly so! Ecological systems are integrative. Runs of cloudy days have different impacts than runs of clear sunny days. A spring with rains every Monday is quite different than a spring with the same amount of rain cluster in a single week. As savers and consumers of data of interest to disturbance scientists, we have our faults. We tend to focus on the day-night and lunar cycles and save and sum-up our data in daily and monthly increments. We add the data up, divide by N and smooth out the extremes. And we lose information, perhaps critical information in the quest to understand disturbance. I think that the Flood of 1993 will legitimize the study of runs and spells of weather and climate over a wide range of time scales. Meteorologists and climatologists need some fresh topics to consume their intellects and grease the wheels of their bandwagons. Publications on runs and spells of weather (bad and good) have a long and but marginalized history in the atmospheric sciences. In my view, systems that have an integrative response to weather, like ecosystems, should especially be impacted by runs and spells of weather and climate. These runs should be seen as disturbances in these systems. My title for this section includes reference to the Noah and Joseph Effects. Floods are often viewed as events and aliased with nom-de-plumes such as the flood-of-the-century or a "200-year flood" based on 50 years of data. It is not unusual to hear of two 100 year floods or two 100 year storms in the same decade or even the same year. Somehow it doesn't fit Gaussian or Markovian statistical models. Real time series have these "outliers." Such events are termed the Noah Effect. The Mississippi Flood of 93 was not so much an event as a long series of events with little in between. There is little indication that the 1993 string of thunderstorms was a random drawing from a normal population of summer-type days. The order of events was clearly not expected. It could be viewed as a disturbance in the time series. Such circumstances are called the Joseph Effect after Joseph's 7 years of plenty and 7 years of famine. So we should consider two kinds of disturbance in climate-ecosystems dynamics. Noah effects, e.g. the 1933 hurricane at Harvard Forest and Hugo at Loquillo and North Inlet LTERs. At the VCR in the 1850s and again in the 1860 there were two Joseph Effect happenings. In both cases there was a run of years with each year having half the long term average amount of rainfall. ***************************************************************** ***************************************************************** *** *** *** *** *** NOAH & JOSEPH: A CED BIBLIOGRAPHY *** *** *** *** *** ***************************************************************** ***************************************************************** Hurst, H. E. 1965. Methods of using long-term storage in reservoirs, Proc. Soc. Civil Eng., 116:770-. Mandelbrot, B. B. and J. R. Wallis. 1968. Noah, Joseph, and operational Hydrology. Water Resources Research 4(5):909-918. Mandelbrot, B. B. and J. R. Wallis. 1969. Computer Experiments with Fractional Gaussian Noises. Part 1, Averages and Variances. Water Resources Research 5(1):228-241. Mandelbrot, B. B. and J. R. Wallis. 1969. Computer Experiments with Fractional Gaussian Noises. Part 2, Rescaled Ranges and Spectra. Water Resources Research 5(1):242-259. Mandelbrot, B. B. and J. R. Wallis. 1969. Computer Experiments with Fractional Gaussian Noises. Part 2, Mathematical Appendix. Water Resources Research 5(1):260-267. Mandelbrot, B. B. and J. R. Wallis. 1969. Some Long-Run Properties of Geophysical Records. Water Resources Research 5(2):321-340. Mandelbrot, B. B. and J. R. Wallis. 1969. Robustness of the Rescaled Range R/S in the Measurement of Noncyclic Long Run Statistical Dependence. Water Resources Research 4(5):909-918. ***************************************************************** ***************************************************************** *** *** *** RESCALED RANGE: *** *** A CROSS-SITE INDEX OF DISTURBANCE *** *** *** ***************************************************************** ***************************************************************** We often view time series of ecological and geophysical variables as having a random normal distribution. If you throw your time series of data into a statistician's black-velvet bag and pull sample after sample, you can chart a frequency versus magnitude histogram. The expectation is to see a random normal, bell shaped, Gaussian distribution. You can then march off and do other statistical tests to punish your data. Our collective dirty little secret is that the majority of people don't often look to see if their numbers confess truthfully to being random-normal. In the modern vernacular, it is "don't ask, don't tell" situation. In time series of natural phenomena, the random normal distribution is hard to find. Hurst (1965) defined a mathematical index for the departure from normality which in now called the Hurst Exponent. In a time series of random normal numbers the Hurst exponent is 0.5. When the ups and downs in the time series are close together (higher frequency variations) the Hurst exponent falls toward 0. When long runs or spells of similar values (above or below the mean or trend of the time series) characterize the time series the Hurst exponent approaches 1.0. If you wish to play around with the Hurst exponent on your own data the means of calculating it will is to be found in the Mandelbrot and Wallis references cited in this CED. If you can wait a bit we will go over it at the Disturbance Workshop at the All Scientists Meeting in Estes Park in September. Its not that it is a hard calculation, it is just that telling you about in these pages would up the boredom index beyond my tolerance. But here is my pitch. If the Hurst exponent tells the data-cruncher about the strength of the tendency for long runs or spell of systematic departures from trends and means then we can use it to compare across sites! For example if we all had a 1900 to the present time series of rainfall we could each calculate Hurst's exponent and thereby intercompare our systems in terms of the prospects of the Joseph Effect. Sites with exponents of 0.5 can go away with a Cheshire-grin and build Guassian-Markov models with confidence. Those sites with Hurst exponents - say around 0.80 - will need to deal with disturbances of the nature that long months or years of wetness or drought. It is sort of like patchiness in time or like non-periodic low-frequency heterogeneity in the time series. [Perhaps a two-dimensional Hurst exponent would help us characterize spatial patchiness!] The Hurst exponent will allow bragging rights among the sites in terms of long-term-but-ephemeral trends that fit perfectly NSF LTER funding duration with renewals! Anyway, disturbance Guru's at LTER sites can come to the Disturbance Workshop and index their way to inter-site harmony. ***************************************************************** ***************************************************************** *** *** *** *** *** RUNS & SPELLS *** *** *** *** *** ***************************************************************** ***************************************************************** Spells of Weather -- the continuance of some type, or repetitive sequence, of weather over several days or weeks. (H.H. Lamb. 1972. Climate: Present, Past and Future. V. 1 Fundamentals and Climate Now. Methuen & Co. LTD. Spells of Climate -- the continuance of some type, or repetitive sequence of climate over several years, decades or centuries. (B.P. Hayden. CED 2.7) I have added to Lamb's definition because spells, in the sense of Lamb, seem to occur on all time scales! After all, it is spells of climate (a kind of disturbance and a Joseph Effect) that should really impact ecosystem dynamics. Ask your favorite farmer and he will tell you that weather and climate comes in runs and spells. A run is usually a short sequence of the same kind weather day after day. Spells more often involve a sequence of weather e.g., rain every Sunday and fair every Wednesday. We could have a run of years with above average rainfall or a spell of years with something like 2 to 3 wet years every 5 years. ***************************************************************** ***************************************************************** *** *** *** *** *** EVERY SUNDAY LOST *** *** *** *** *** ***************************************************************** ***************************************************************** Each year and each season has its "weather or climate character" as a result of the spells of weather that make it up. Often the spell is made of up weather events of a particular character falling on the same day of the week, week after weak after week. Once I mentioned all this to my best-secretary-ever of some years back (I have computerized her out of a job.) She told me that "Everybody knows that." I see her from time to time and she yells out her observations: "It's Tuesday this Spring. Every Tuesday!" She keeps notes on her desk calendar and boldly predicts the weather a week in advance. Once you note the pattern it is very hard for the weather service and its numerical models to out forecast you at the 7 days into the future much less 14 and 21 days out! Just say: Next Friday will be like last Friday but more normal and you are in the know! This weekly cycle is often present, especially in the winter half of the year. However, in any one year, it could fall on any of the 7 days that make up our weekly, work-a-day world. If we had 8 days in the week with each named so we could remember them, we would, perhaps, tend to see years with 8 day cycles. Actually this is often the case during the summer half of the year. That is my observation based on my years work on coastal storms and beach wave climates along the Atlantic coast. Use and look for weather spells of 7 days return in winter and 8 days in summer. This cycle, sometimes called the synoptic cycle, records the time between crossings of weather systems across the span of North America. In winter you can, in some years, see a 3.5 day cycle with every other one being stronger. Keeping a calendar is the best way to become aware of runs of weather like these. Without a calendar you have to rely on getting washed out of every Saturday afternoon football game or enjoying the Tuesday afternoon youth soccer league quagmire. The best paper on the subject is by Jerry Namias of Scripps. J. Namias 1966. A weekly periodicity in eastern U.S. precipitation and its relation to hemispheric circulation. Tellus XVIII:731-744. December 1, 1964 - February 14, 1965 (76 days) 39 STATIONS IN NJ, PA, OH, IN, VA, WV, KY, TN, NC, SC, GA, AL, FL _____________________________________________ December 1, 1964 - February 14, 1965 (76 days) Average of 29 Stations _____________________________________________ Day of Week (ave. rain, ave. number of rains) Sunday (2.71, 6.7) Monday (0.29, 2.1) Tuesday (0.36, 2.3) Wednesday 0.39, 1.8) Thursday (0.54, 2.7) Friday (2.36, 4.9) Saturday (3.01, 6.7) _____________________________________________ In the example above, the day on which the rain tends to fall depends somewhat on geography. Mobil to the South and West of Richmond gets its rain a day earlier. Richmond got its rain on Sunday and Mobile on Saturday. The goose-eggs in rainfall totals in the middle of the week is also noteworthy. ________________________________________________________________________ SUN MON TUE WED THU FRI SAT ________________________________________________________________________ Richmond, VA: 4.45", 0.31", 0.00", 0.14", 0.05", 0.40", 1.75" Mobil, AL: 0.94", 0.21", 0.38", 0.00", 0.44", 3.74", 10.13" ________________________________________________________________________ Runs and spells such as these require that the waves in the jet stream march their way across the continent in an orderly manner. If their speed of propagation is fast, the synoptic cycle could shorten to less than 7 days or if the propagation is slowed then the cycle could be longer than 7 days. Of course the propagation speed (celarity in Rossby's frequency equation) can go to ZERO. Than the weather becomes persistent from day to day. The Flood of 93 sure fits this bill. People - guys who know some meteorological jargon - start mumbling about blocking patterns in the circulation of the atmosphere. The wave or trough in the jet stream, in this case, parked itself over the upper Mississippi Valley and stayed put. The same weather day after day. The divergence of mass aloft gave support to the growth of thunderstorms. This spell was made up of a run of days [a month and a half] with essentially the same weather. Iowa got rain. Virginia got hot. Here is how it works. The wet air for the thunderstorms came from the subtropical North Atlantic, the Caribbean and the Gulf of Mexico. Solar calories were invested in evaporating water not in heat the air (84 F isn't so bad). The wet air made its way up the Mississippi Valley. This is an every year thing so far. With the dip in the jet stream conditions were very supportive of thunderstorms. With the lifting of this wet air condensation and rain drop formations released the calories as sensible heat and the potential temperature of the air got higher and higher. (Potential temperature is the temperature it would be if brought back to about sea level.) Now this high potential air moved east and sank down into the Bermuda High which resided over the east and southeast as persistently as the thunderstorms of Iowa. This high potential temperature air at the ground in Virginia assured temperatures in the upper 90s. It was hot, humid and hazy. Tropical heat for Virginia by way of Iowa. ***************************************************************** ***************************************************************** *** *** *** *** *** TEENAGERS CAUSE WINTER *** *** *** *** *** ***************************************************************** ***************************************************************** "Teenagers Cause Winter" is the topic sentence of "Agents of Ice" Gary L. Gaile and Dean M. Hanink (1985) AREA 17(2):165-167. I must admit I had not read anything from the journal Area and must credit David Greenland (Andrews) for passing it along to me. David, on his stick-on yellow slip, noted that "Gary is very good at this." Lets look at a bit of Gary's data to get started. The hypothesis that teenagers cause winter that the more teenagers there are in the population the more winter-like winter is! Gary uses the % of the population between 5 and 17 years of age to track the causers and mean January Temperature to index winter severity. Gary's regression is Temperature = 180.3 - 7.04 Age [R = -0.869, a = 0.0001, R squared = 0.755, F = 203.6]. Gary used 68 U.S. as the data source for torture. At the the-children-shall-rule end of the spectrum is St. Cloud, MN with 23.2% of the populations with skin problems and a January mean temperature of 8.9 F. Ft.Lauderdale (naturally) has only 16.1% of the population invested in youth and a nice 66.8 F average January temperature. I have a good friend who claims that ecologists as a lot have failed the Darwin's test. In my department non-adopted offsprings of our academic faculty calling themselves ecologists is but 2! By Gary's calculus, ecologists must be a force for global warming. Gary's bibliography is helpful. Allen, J.L. (1954 Chevrolet) 'Killer teens: the Lewis and Clark expedition' in Belmonts, Dion and the (eds) Festschrift for Dobie Gillis (Beach Blanket Press, Malibu CA), 212-490 + maps and apology. Allen, J. L. (1985) ' the Holly-Bopper expedition' in Scott, Willard (ed.) Flights of fancy (Tomorrow's News Today Press, Burbank CA), available only on Video Disc. Wilmontt, P. J. (1984) 'Climastrology: what's your sign and why you treat me so cold? Journal of Adolescent Climatology 17(2)3-4. Gary's list of needed future research: 1) What is the effect of marijuana smoke or acne vapor on the ozone layer? 2) Do the more efficient digestive systems of teenagers substantially reduce the amount of super heated gaseous effluent in the atmosphere? 3) What did Meg Trudeau do with the Rolling Stones?, and 4) Can teenagers and winter be eliminated? Causality: 1)Teenagers try to act cool. 2) It is also known that they frequently leave the refrigerator door open. 3) Youth import snow from Colombia. 4) They grow long hair for natural protection and they move south when balding sets in. 5) In the summer they soak up the rays. AREA appears to be a journal worth reading. If your library doesn't carry it use inter-library loan. If all else fails, see Hayden at the All Scientist Meeting in Estes Park in September. ***************************************************************** ***************************************************************** *** *** *** *** *** ALL SCIENTIST MEETING *** *** CEPHLOMETRIC SURVEY *** *** *** ***************************************************************** ***************************************************************** The CED cephlometric survey taken on the Alaska Pipeline Highway and in the environs of Tulik Lake has been called into question. The question comes from a closet survey. An intrepid CED reader went to his closet and found ballcaps for all occasions. His caps with the plastic cephlometer for the one-size-fits-all cap-attribute were not identical. He found that some of his cap gave a cranial estimate of three hole others said as much as six hole. As a result it will be necessary to bring to Estes Park an official CED cephlometer. It will be displayed in the poster hall and all can come, measure and rejoice. Results will appear in the following CED.