Climatic temperatures, isotope

Epstein and Yapp [4] state "it is obviously necessary to calibrate more specifically the relationship between 6(D) records in cellulose nitrate from tree-ring records and known climatic records. This can probably be done best by the analysis of tree rings from widely different, well-documented environments. Such data will allow the comparison of a large variety of trees and determine the versatility of using the isotopic method for climatic temperature determination". We concur with this statement as long as "from the same population" is inserted. 

Long term changes in precipitation, caused by changes in climatic temperature, are well documented in polar ice caps the heavier of the stable isotopes is depleted in ice laid down in the ice age by comparison with present day ice. In 1970 we extended this concept to trees, suggesting that they, also, are thermometers. Trees grow from water and atmospheric C02. In trees which grow on rain water, isotope variations in their rings should be climate indicators because the isotope composition in rain and C02 varies with temperature. 

But isotope fractionation at climatic temperatures is a function of the frequencies of the chemical bonds [16]. We quote from Herzberg [19] as follows "One would expect the -C-H bond to have essentially the same electronic structure and therefore the same force constant in different molecules, and similarly for other bonds. This is indeed observed". For the -C-H bonds the vibrational frequencies in lignin and in cellulose are almost equal, but in fact differ by 6 percent [19] because cellulose is a multiple alcohol (H-C-0-H)n and lignin is a polymer containing... 

The isotopic compositions of oxygen and hydrogen in cellulose are particularly influenced by the climate in which the plant grew. Climate affects isotope ratios in primarily two ways. First, temperature affects cellulose... 

Knauth L. P. and Lowe D. R. (2003) High Archean climatic temperature inferred from oxygen isotope geochemistry of cherts in the 3.5 Ga Swaziland Supergroup, South Africa. GSA Bull. 115, 566-580. 

Oxygen isotope data from Pacific-cores foraminifera and belemnites showed that low-latitude bottom water temperatures fell firom >15°C to about 10-12°C at the end of the Cretaceous. A Cretaceous maximum occurred in the Albian (Teis et al. 1969). This did not agree with other data indicating a climatic temperature maximum in the Coniacian/Santonian almost 11 million years later. The disparity might have been due to a different ratio in... 

The GRIP 8 0 profile has been converted to a climatic temperature signal by using the calibration from Fig. 3. The resulting temperature history is shown in Fig. 9 as deviations from the present Summit temperature corrected for past elevation changes. The correlation to die marine isotope stages (MIS) is marked to die right. 

Jouzel, J., Lorius, J. R., Petit, C. et al. (1993). Vostok ice-core - a continuous isotope temperature record over the last climatic cycle (160000 years). Nature 329,403 08. 

The power of this technique is due to the fact that the temperature-depth profile is a direct remnant of paleotemperatures at the ice-sheet surface. It provides a quantitatively accurate measure of long-term average temperatures. This allows the stable isotope records to be calibrated for major climate events (Cuffey et ah, 1995). 

Suggestions that phosphatic minerals in mammals could be used, however, revived the interest in climate reconstruction in continental interiors. Aquatic, cold-blooded animals like fish have body temperatures and body water oxygen isotopic compositions that are directly dependent on the water in which they live. For these animals, a commonly used equation describes the relationships among temperature, water oxygen isotopic composition and phosphate oxygen isotopic composition as (Longinelli and Nuti 1973 verified by Kolodny et al. 1983, among others) ... 

I apply these computational methods to various aspects of the Earth system, including the responses of ocean and atmosphere to the combustion of fossil fuels, the influence of biological activity on the variation of seawater composition between ocean basins, the oxidation-reduction balance of the deep sea, perturbations of the climate system and their effect on surface temperatures, carbon isotopes and the influence of fossil fuel combustion, the effect of evaporation on the composition of seawater, and diagenesis in carbonate sediments. These applications have not been fully developed as research studies rather, they are presented as potentially interesting applications of the computational methods. 

Chapter 8 presented the last of the computational approaches that I find widely useful in the numerical simulation of environmental properties. The routines of Chapter 8 can be applied to systems of several interacting species in a one-dimensional chain of identical reservoirs, whereas the routines of Chapter 7 are a somewhat more efficient approach to that chain of identical reservoirs that can be used when there is only one species to be considered. Chapter 7 also presented subroutines applicable to a generally useful but simple climate model, an energy balance climate model with seasonal change in temperature. Chapter 6 described the peculiar features of equations for changes in isotope ratios that arise because isotope ratios are ratios and not conserved quantities. Calculations of isotope ratios can be based directly on calculations of concentration, with essentially the same sources and sinks, provided that extra terms are included in the equations for rates of change of isotope ratios. These extra terms were derived in Chapter 6. 

It is a pleasure to thank Rudolph Black of the United States Advanced Research Projects Agency, who, in May 1971, funded our proposal that "temperature variations in past climates may be evaluated by measuring stable isotope ratios in natural data banks such as tree ring and varve sequences". We thank William Best of the U.S. Air Force Office of Scientific Research who monitored our study and Frank Eden of the U.S. National Science Foundation who subsequently provided further funds. 

Thus <5180 in the precipitation becomes increasingly positive (i.e., isotopically heavier) as the average air temperature rises. This relationship has been used to convert the 5lsO record obtained from Greenland (Johnsen el al. 1997) and Antarctic (Grootes and Stuiver 1986) ice core records into palaeotemperature records, thus giving a climatic framework for the past 420 000 years. 

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