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21.
Uwe Mikolajewicz Matthias Gröger Ernst Maier-Reimer Guy Schurgers Miren Vizcaíno Arne M. E. Winguth 《Climate Dynamics》2007,28(6):599-633
A new complex earth system model consisting of an atmospheric general circulation model, an ocean general circulation model,
a three-dimensional ice sheet model, a marine biogeochemistry model, and a dynamic vegetation model was used to study the
long-term response to anthropogenic carbon emissions. The prescribed emissions follow estimates of past emissions for the
period 1751–2000 and standard IPCC emission scenarios up to the year 2100. After 2100, an exponential decrease of the emissions
was assumed. For each of the scenarios, a small ensemble of simulations was carried out. The North Atlantic overturning collapsed
in the high emission scenario (A2) simulations. In the low emission scenario (B1), only a temporary weakening of the deep
water formation in the North Atlantic is predicted. The moderate emission scenario (A1B) brings the system close to its bifurcation
point, with three out of five runs leading to a collapsed North Atlantic overturning circulation. The atmospheric moisture
transport predominantly contributes to the collapse of the deep water formation. In the simulations with collapsed deep water
formation in the North Atlantic a substantial cooling over parts of the North Atlantic is simulated. Anthropogenic climate
change substantially reduces the ability of land and ocean to sequester anthropogenic carbon. The simulated effect of a collapse
of the deep water formation in the North Atlantic on the atmospheric CO2 concentration turned out to be relatively small. The volume of the Greenland ice sheet is reduced, but its contribution to
global mean sea level is almost counterbalanced by the growth of the Antarctic ice sheet due to enhanced snowfall. The modifications
of the high latitude freshwater input due to the simulated changes in mass balance of the ice sheet are one order of magnitude
smaller than the changes due to atmospheric moisture transport. After the year 3000, the global mean surface temperature is
predicted to be almost constant due to the compensating effects of decreasing atmospheric CO2 concentrations due to oceanic uptake and delayed response to increasing atmospheric CO2 concentrations before. 相似文献
22.
Inggard Arne Blakar 《Aquatic Sciences - Research Across Boundaries》1978,40(1):191-198
A highly flexible and efficient gravity corer, easy to construct from inexpensive and readily available material, is described. Barrels of various length can be swiftly interchanged according to requirements in the field. Hollow weights can easily be adjusted to the most appropriate height of the barrel. The simple but reliable closing valve (constructed of two plastic funnels) can be adapted to other types of gravity corers as well. Several useful modifications of the corer are discussed. 相似文献
23.
Arne Råheim 《Lithos》1975,8(3):221-236
Ferromagnesian minerals, particularly garnet but also phengite, omphacite and talc, from eclogites and surrounding schists from the Lyell Highway-Collingwood river area, western Tasmania are compositionally zoned.In rocks which have suffered little secondary alteration the Mg-value () of granets increases from core to rim, while the Mg-value of the most important coexisting ferromagnesian phases (clinopyroxene, phengite and talc in different assemblages) decreases from core to rim. CaO decreases from core to rim in garnet. MnO may show little or no variation in garnet, or decrease from core to rim.When compared with experimental data, the zoning of these minerals can be uniquely explained by growth during changing P,T conditions. The eclogites and the surrounding schists have the same prograde P,T history.When determining the KD-values of garnet and its coexisting ferromagnesian phases it is important to consider secondary rim alterations as well as the prograde zoning of the mineral. 相似文献
24.
Inggard Arne Blakar 《Aquatic Sciences - Research Across Boundaries》1980,42(1):78-83
A simple, cheap and easily constructable burette, particularly useful for alkalinity, dissolved oxygen and hardness titration is described. Precise titrant delivery (<1 μl) is controlled by a handy ‘clothespin valve’ connected to the lower opening of appropriately sized graduated pipettes or burette tubes. The burette is small, flexible and easily portable and should be highly recommended as an all round field burette for limnochemists. 相似文献
25.
Experimental data combined with data from natural rocks have been used to calibrate a geothermometer based on the distribution of Fe2+ and Mg between coexisting garnets and phengites. The pressure effect on the K D -value appears to be considerable. The calculated thermometer is expressed as $$T(K) = \frac{{3685 + 77.1P(kb)}}{{InK_D + 3.52}}.$$ The use of this \(K_{D_{(FeO/MgO)} }^{ga + ph}\) geothermometer on eclogites with low Fe2O3 content, gives P-T values which are in good accordance with those obtained by other methods. The problems that arise when Fe3+ is present in larger amounts, are discussed. 相似文献
26.
Arne Olsen 《Contributions to Mineralogy and Petrology》1974,47(2):141-152
Plagioclase feldspars with mean compositions Ab91,3Or4,7An4,0 and Ab88,7An10,1Or1,2 have been studied by transmission electron microscopy and electron diffraction. The substructure consists of thin lamellae of albite and oligoclase. Two types of orientations of the lamellar planes were observed. The orientation of the more common type was found to change from (08 \(\bar 1\) ) to about ( \(\bar 1\) , 21, \(\bar 2\) ) as a function of the mean potassium content. The plane of the other type was found to be near ( \(\bar 7\) 12). Only the first type of lamellae produces visible Schiller colours. 相似文献
27.
Talc-garnet-kyanite-quartz schist occurs in an eclogite-bearing terrane in the Precambrian of Western Tasmania. It is argued that this rock was formed at a pressure of ? 10 kb and a temperature of 600°±20° C. Chemical zoning in the garnet and talc preserves evidence of increasing temperature during growth of the major minerals. 相似文献
28.
Albert M. Fowler K. Michael Merrill William Ball Arne Henden Fred Vrba Craig McCreight 《Experimental Astronomy》2002,14(1):61-68
The Orion program is a project to develop a 2K × 2K infrared focal plane using InSb p-on-n diodes for detectors. It is the
natural follow-up to the successful Aladdin 1K × 1K program started in the early 90's. The work is being done at the Raytheon
Infrared Operations Division (RIO, previously known as the Santa Barbara Research Center) by many of the same people who created
the Aladdin focal plane. The design is very similar to the successful Aladdin design with the addition of reference pixels,
whole array readout (no quadrants), two-adjacent-side buttability, and a packaging design that includes going directly to
the ultimate focal plane size of 4K × 4K. So far we have successfully made a limited number of hybrid modules with InSb detectors.
In this paper we will describe the design features and test data taken from some of these devices.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
29.
Paleomagnetic constraints on Zn–Pb ore genesis of the Pillara Mine, Lennard Shelf, Western Australia
The Pillara Zn–Pb deposit is the largest of several known Mississippi Valley-type (MVT) deposits in the Lennard Shelf of the Canning Basin. Paleomagnetic and rock magnetic measurements are reported for 294 specimens from 23 sites in mineralization and its carbonate host rocks from the deposit as well as on 15 artificial specimens of zinc and lead concentrate and of tailings. Pyrrhotite carries the characteristic remanent magnetization (ChRM) in nearly all specimens. The ChRM postdates most faulting as shown by breccia tests and most minor regional tilting as shown by the degraded fit on tilt correction. The mean ChRM direction for all sites is D=20.6°, I=–27.5° (N=23, 95=5.3°, k=34.1), yielding an age of 358±5 Ma (2) that is similar to the comparable age of 354±8 Ma (2) for the Kapok MVT deposit. Host rock diagenesis with attendant secondary remagnetization yields an age of 361±5 Ma (1) and the MVT mineralization with a primary chemical remanent magnetization gives an age of 356±3 Ma (1), co-eval with a published Rb–Sr sphalerite age of 357±3 Ma. Interpretation of this temporal data suggests that the MVT deposits of the southeastern Lennard Shelf originated during extension, probably in response to rift-related topography-driven fluid flow.Editorial handling: C. Brauhart 相似文献
30.
A numerical application to the extreme cases of high and low degree of ionization of the binary collision theory of Burgers (1960) and the multiple collision theory of Shkarofsky (1960) shows very good agreement in the values of the magnetic tensor components for solar electrical conductivity. It is pointed out that the inclusion of ion motions in Burgers theory favors its use in the future evaluation of the solar thermal conductivity tensor.The research reported in this paper was sponsored by the Air Force Cambridge Research Laboratories, AFSC, under Contract F19628-70-C-0192-P00001, but the report does not necessarily reflect endorsement by the sponsor. 相似文献