Sub‐millennial climate shifts in the western Mediterranean during the last glacial period recorded in a speleothem from Mallorca,Spain     

Edward J. Hodge  David A. Richards  Peter L. Smart  Angel Gins  David P. Mattey 《第四纪科学杂志》2008,23(8):713-718

Very few high‐resolution and directly dated terrestrial archives of the last glacial period exist for the western Mediterranean region, yet this is a key locality for recording sub‐millennial North Atlantic and Mediterranean climate change. Here, we present evidence of effective precipitation changes based on growth history and δ¹³C of calcite in a Mallorcan stalagmite that grew between 112 and 48 ka. Effective precipitation in Mallorca appears to have been sensitive to proximal sea surface temperature variations and at certain times, ca. 76 ka for example, changed rapidly from moist to arid conditions in only a few centuries. A sea‐level highstand during Marine Isotope Stage (MIS) 5a interrupted growth. Regrowth started promptly after this, but effective precipitation decreased markedly for much of the later part of MIS 5a, and also for shorter periods correlative with Heinrich events H8 (ca. 90 ka) and H6 (ca. 65 ka), with growth ceasing during H5 (ca. 48 ka). Arid episodes in Mallorca appear to be expressions of extremely cold periods recorded further north in Europe and occur contemporaneously with rapid decreases in Greenland temperature. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

The star formation histories of elliptical galaxies across the Fundamental Plane     

L. A. Nolan  J. S. Dunlop  B. Panter  Raul Jimenez  A. Heavens  G. Smith 《Monthly notices of the Royal Astronomical Society》2007,375(1):371-380

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Regional aerosol optical depth characteristics from satellite observations: ACE‐1, TARFOX and ACE‐2 results     

P. A. Durkee  K. E. Nielsen  P. J. Smith  P. B. Russell  B. Schmid  J. M. Livingston  B. N. Holben  C. Tomasi  V. Vitale  D. Collins  R. C. Flagan  J. H. Seinfeld  K. J. Noone  E. Öström  S. Gassó  D. Hegg  L. M. Russell  T. S. Bates  P. K. Quinn 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):484-497

Analysis of the aerosol properties during 3 recent international field campaigns (ACE‐1, TARFOX and ACE‐2) are described using satellite retrievals from NOAA AVHRR data. Validation of the satellite retrieval procedure is performed with airborne, shipboard, and land‐based sunphotometry during ACE‐2. The intercomparison between satellite and surface optical depths has a correlation coefficient of 0.93 for 630 nm wavelength and 0.92 for 860 nm wavelength. The standard error of estimate is 0.025 for 630 nm wavelength and 0.023 for 860 nm wavelength. Regional aerosol properties are examined in composite analysis of aerosol optical properties from the ACE‐1, TARFOX and ACE‐2 regions. ACE‐1 and ACE‐2 regions have strong modes in the distribution of optical depth around 0.1, but the ACE‐2 tails toward higher values yielding an average of 0.16 consistent with pollution and dust aerosol intrusions. The TARFOX region has a noticeable mode of 0.2, but has significant spread of aerosol optical depth values consistent with the varied continental aerosol constituents off the eastern North American Coast.  相似文献   

Tsunami: a research perspective     

David Smith 《Geology Today》2005,21(2):64-68

Over the past several years, tsunami research has been growing strongly, stimulated by an increasing interest in extreme events amongst geologists and geographers and supported by improved levels of funding from both public and private sectors in a number of countries. These developments are timely, and should ultimately result in a better perspective than we might otherwise have had on the origins and nature of the Sumatra tsunami that resulted in the loss of so many lives. This account summarizes the origins of tsunami in general and outlines the terminology used before describing some recent developments in tsunami research.  相似文献   

Comprehensive simulations of superhumps     

Amanda J. Smith  Carole A. Haswell  James R. Murray  Michael R. Truss  Stephen B. Foulkes 《Monthly notices of the Royal Astronomical Society》2007,378(3):785-800

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Enceladus: The likely dominant nitrogen source in Saturn's magnetosphere     

H.T. Smith  R.E. Johnson  M. Shappirio  O.J. Tucker  F.J. Crary  D.T. Young 《Icarus》2007,188(2):356-366

The spatial distribution of N⁺ in Saturn's magnetosphere obtained from Cassini Plasma Spectrometer (CAPS) data can be used to determine the spatial distribution and relative importance of the nitrogen sources for Saturn's magnetosphere. We first summarize CAPS data from 15 orbits showing the spatial and energy distribution of the nitrogen component of the plasma. This analysis re-enforces our earlier discovery [Smith, H.T., Shappirio, M., Sittler, E.C., Reisenfeld, D., Johnson, R.E., Baragiola, R.A., Crary, F.J., McComas, D.J., Young, D.T., 2005. Geophys. Res. Lett. 32 (14). L14S03] that Enceladus is likely the dominant nitrogen source for Saturn's inner magnetosphere. We also find a sharp enhancement in the nitrogen ion to water ion ratio near the orbit of Enceladus which, we show, is consistent with the presence of a narrow Enceladus torus as described in [Johnson, R.E., Liu, M., Sittler Jr., E.C., 2005. Geophys. Res. Lett. 32. L24201]. The CAPS data and the model described below indicate that N⁺ ions are a significant fraction of the plasma in this narrow torus. We then simulated the combined Enceladus and Titan nitrogen sources using the CAPS data as a constraint. This simulation is an extension of the model we employed earlier to describe the neutral tori produced by the loss of nitrogen from Titan [Smith, H.T., Johnson, R.E., Shematovich, V.I., 2004. Geophys. Res. Lett. 31 (16). L16804]. We show that Enceladus is the principal nitrogen source in the inner magnetosphere but Titan might account for a fraction of the observed nitrogen ions at the largest distances discussed. We also show that the CAPS data is consistent with Enceladus being a molecular nitrogen source with a nitrogen to water ratio roughly consistent with INMS [Waite, J.H., and 13 colleagues, 2006. Science 311 (5766), 1419-1422], but out-gassing of other nitrogen-containing species, such as ammonia, cannot be ruled out.  相似文献   

Reply to the comments of Macdonald et al. on "Rivers runoff and reefs" [Global and Planetary Change 39 (2003) 191–199]     

C.J. McLaughlin  C.A. Smith  R.W. Buddemeier  J.D. Bartley  B.A. Maxwell   《Global and Planetary Change》2005,45(4):339-341

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Raman confirmation of microdiamond in the Svartberget Fe‐Ti type garnet peridotite,Western Gneiss Region,Western Norway     

J. C. Vrijmoed  D. C. Smith  H. L. M. Van Roermund 《地学学报》2008,20(4):295-301

Ultra‐high pressure metamorphic rocks have been found worldwide. The volume and areal extent of an exhumed UHPM domain are important for understanding the geodynamic mechanisms responsible for the high pressure and relatively medium temperature conditions needed for their creation. We report here Raman microspectroscopical data that prove the existence of microdiamonds at the Svartberget Fe‐Ti type peridotite locality in the Western Gneiss Region of Norway. Raman microscopy of two carbon microinclusions belonging to polyphase inclusion assemblages included in garnets from a garnet‐phlogopite websterite vein yielded a sharp, narrow, intense peak at 1332 cm^?1, characteristic of diamond. The diamond is associated with polyphase solid inclusions possibly originating from supercritical, dense, H‐C‐N‐O‐F‐P‐S‐Cl fluids. Lithological, textural and geochronological evidence points towards a Caledonian origin of the trapped fluid and subsequent diamond formation.  相似文献   

The discovery of a massive supercluster at  z= 0.9  in the UKIDSS Deep eXtragalactic Survey     

A. M. Swinbank  A. C. Edge  Ian Smail  J. P. Stott  M. Bremer  Y. Sato  C. van Breukelen  M. Jarvis  I. Waddington  L. Clewley  J. Bergeron  G. Cotter  S. Dye  J. E. Geach  E. Gonzalez-Solares  P. Hirst  R. J. Ivison  S. Rawlings  C. Simpson  G. P. Smith  A. Verma  T. Yamada 《Monthly notices of the Royal Astronomical Society》2007,379(4):1343-1351

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Dawn Mission to Vesta and Ceres     

C. T. Russell  F. Capaccioni  A. Coradini  M. C. De Sanctis  W. C. Feldman  R. Jaumann  H. U. Keller  T. B. McCord  L. A. McFadden  S. Mottola  C. M. Pieters  T. H. Prettyman  C. A. Raymond  M. V. Sykes  D. E. Smith  M. T. Zuber 《Earth, Moon, and Planets》2007,101(1-2):65-91

The initial exploration of any planetary object requires a careful mission design guided by our knowledge of that object as gained by terrestrial observers. This process is very evident in the development of the Dawn mission to the minor planets 1 Ceres and 4 Vesta. This mission was designed to verify the basaltic nature of Vesta inferred both from its reflectance spectrum and from the composition of the howardite, eucrite and diogenite meteorites believed to have originated on Vesta. Hubble Space Telescope observations have determined Vesta’s size and shape, which, together with masses inferred from gravitational perturbations, have provided estimates of its density. These investigations have enabled the Dawn team to choose the appropriate instrumentation and to design its orbital operations at Vesta. Until recently Ceres has remained more of an enigma. Adaptive-optics and HST observations now have provided data from which we can begin to confidently plan the mission. These observations reveal a rotationally symmetric body with little surface relief, an ultraviolet bright point that can be used as a control point for determining the pole and anchoring a geographic coordinate system. They also reveal albedo and color variations that provide tantalizing hints of surface processes.  相似文献