A step-response approach for predicting and understanding non-linear precipitation changes   总被引：1，自引：1，他引：0  

Peter Good  William Ingram  F. Hugo Lambert  Jason A. Lowe  Jonathan M. Gregory  Mark J. Webb  Mark A. Ringer  Peili Wu 《Climate Dynamics》2012,39(12):2789-2803

Future changes in precipitation represent one of the most important and uncertain possible effects of future climate change. We demonstrate a new approach based on idealised CO₂ step-change general circulation model (GCM) experiments, and test it using the HadCM3 GCM. The approach has two purposes: to help understand GCM projections, and to build and test a fast simple model for precipitation projections under a wide range of forcing scenarios. Overall, we find that the CO₂ step experiments contain much information that is relevant to transient projections, but that is more easily extracted due to the idealised experimental design. We find that the temporary acceleration of global-mean precipitation in this GCM following CO₂ ramp-down cannot be fully explained simply using linear responses to CO₂ and temperature. A more complete explanation can be achieved with an additional term representing interaction between CO₂ and temperature effects. Energy budget analysis of this term is dominated by clear-sky outgoing long-wave radiation (CSOLR) and sensible heating, but cloud and short-wave terms also contribute. The dominant CSOLR interaction is attributable to increased CO₂ raising the mean emission level to colder altitudes, which reduces the rate of increase of OLR with warming. This behaviour can be reproduced by our simple model. On regional scales, we compare our approach with linear ‘pattern-scaling’ (scaling regional responses by global-mean temperature change). In regions where our model predicts linear change, pattern-scaling works equally well. In some regions, however, substantial deviations from linear scaling with global-mean temperature are found, and our simple model provides more accurate projections. The idealised experiments reveal a complex pattern of non-linear behaviour. There are likely to be a range of controlling physical mechanisms, different from those dominating the global-mean response, requiring focussed investigation for individual regions, and in other GCMs.  相似文献   

Heavy element abundances in DAO white dwarfs measured from FUSE data     

S. A. Good  M. A. Barstow  M. R. Burleigh  P. D. Dobbie  J. B. Holberg  I. Hubeny 《Monthly notices of the Royal Astronomical Society》2005,363(1):183-196

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The low-mass white dwarf companion to β Crateris     

M.R. Burleigh  M.A. Barstow  K.J. Schenker  A.I. Sills  G.A. Wynn  P.D. Dobbie  S.A. Good 《Monthly notices of the Royal Astronomical Society》2001,327(4):1158-1164

We present FUSE H Lyman series spectroscopy of the hot white dwarf companion to the 4th magnitude A1 III star β  Crt, which shows that it has an unusually low mass,     , and has almost certainly evolved through binary interaction. This system could be a long-sought remnant of Algol-type evolution, although radial velocity measurements appear to show that the pair are not close. Instead, micro-variations in the proper motion of β  Crt as measured by Hipparcos suggest that the period could be as high as ∼10 yr. However, a low-mass white dwarf in a system with a period ≳3 yr is difficult to explain by conventional models for binary evolution. We speculate on alternative models for the evolution of this system which involve an eccentric binary or multiple components.  相似文献   

A comparison of DA white dwarf temperatures and gravities from Lyman and Balmer line studies     

M.A. Barstow  J.B. Holberg  I. Hubeny  S.A. Good  A.J. Levan  F. Meru 《Monthly notices of the Royal Astronomical Society》2001,328(1):211-222

The stability of turbulent accretion discs is considered, in which a magnetically influenced wind plays a major role in driving the inflow. The magnetic field is generated by a dynamo operating in the disc, involving radial shear and turbulence. The steady angular momentum balance is found to be linearly stable for a range of radial boundary conditions, and an expression is derived for the adjustment time-scale as a function of the equilibrium ratio of the magnetic and viscous disc torques.  相似文献   

Modelling the impact of climate extremes: an overview of the MICE project     

C. E. Hanson  J. P. Palutikof  M. T. J. Livermore  L. Barring  M. Bindi  J. Corte-Real  R. Durao  C. Giannakopoulos  P. Good  T. Holt  Z. Kundzewicz  G. C. Leckebusch  M. Moriondo  M. Radziejewski  J. Santos  P. Schlyter  M. Schwarb  I. Stjernquist  U. Ulbrich 《Climatic change》2007,81(1):163-177

This paper provides an overview of the aims, objectives, research activities undertaken, and a selection of results generated in the European Commission-funded project entitled “Modelling the Impact of Climate Extremes” (MICE) – a pan-European end-to-end assessment, from climate model to impact model, of the potential impacts of climate change on a range of economic sectors important to the region. MICE focussed on changes in temperature, precipitation and wind extremes. The research programme had three main themes – the evaluation of climate model performance, an assessment of the potential future changes in the occurrence of extremes, and an examination of the impacts of changes in extremes on six activity sectors using a blend of quantitative modelling and expert judgement techniques. MICE culminated in a large stakeholder-orientated workshop, the aim of which was not only to disseminate project results but also to develop new stakeholder networks, whose expertise can be drawn on in future projects such as ENSEMBLES. MICE is part of a cluster of three projects, all related to European climate change and its impacts. The other projects in the cluster are PRUDENCE (Prediction of Regional Scenarios and Uncertainties for Defining European Climate Change Risks and Effects) and STARDEX (Statistical and Regional Dynamical Downscaling of Extremes for European Regions).  相似文献   

Interannual-decadal variability of wintertime mixed layer depths in the North Pacific detected by an ensemble of ocean syntheses     

Toyoda  Takahiro  Fujii  Yosuke  Kuragano  Tsurane  Kosugi  Naohiro  Sasano  Daisuke  Kamachi  Masafumi  Ishikawa  Yoichi  Masuda  Shuhei  Sato  Kanako  Awaji  Toshiyuki  Hernandez  Fabrice  Ferry  Nicolas  Guinehut  Stéphanie  Martin  Matthew  Andrew Peterson  K.  Good  Simon A.  Valdivieso  Maria  Haines  Keith  Storto  Andrea  Masina  Simona  Köhl  Armin  Yin  Yonghong  Shi  Li  Alves  Oscar  Smith  Gregory  Chang  You-Soon  Vernieres  Guillaume  Wang  Xiaochun  Forget  Gael  Heimbach  Patrick  Wang  Ou  Fukumori  Ichiro  Lee  Tong  Zuo  Hao  Balmaseda  Magdalena 《Climate Dynamics》2017,49(3):891-907

Climate Dynamics - The interannual-decadal variability of the wintertime mixed layer depths (MLDs) over the North Pacific is investigated from an empirical orthogonal function (EOF) analysis of an...  相似文献   

Measurements of the turbulence characteristics of sand suspended by a tidal current     

R.L. Soulsby  A.P. Salkield  G.P. Le Good 《Continental Shelf Research》1984,3(4):439-454

Measurements made with a new fast-response suspended sand sensor have for the first time enabled the turbulence characteristics of a natural sand suspension to be studied. Suspended sand concentration measurements, together with fast-response current measurements, were made 18 cm above a sandy bed under a strong tidal current. They showed a highly variable concentration field, dominated by clouds of sand which took 2 to 10 s to sweep past the sensor. The concentration spectrum had peak energy at a wavelength of about 3 m, and exhibited a −5/3 power dependence at high frequencies. Damping of the turbulence intensity of the current was observed when sand was suspended. A spectral approach produced more plausible values for the upward Reynolds flux of sediment than the direct covariance technique. The calculated upward fluxes were appreciably smaller than the settling fluxes around the time of maximum current, contrary to the expectation for an equilibrium concentration profile. The turbulence characteristics of the concentration field displayed marked similarities with standard results from atmospheric temperature measurements, strengthening assumptions commonly made in the prediction of sediment transport rates.  相似文献   

A secondary clinopyroxene-chlorite-spinel assemblage in clinopyroxenite of the Mann complex, Abitibi Belt, Ontario: An unusual hydrothermal alteration suite   总被引：1，自引：0，他引：1  

D. J. Good  J. H. Crocket  R. L. Barnett 《Mineralogy and Petrology》1997,59(1-2):69-90

Summary Small dispersed patches (< 1 cm) of chlorite + secondary clinopyroxene ± spinel occur within a unit of clinopyroxenite in a mafic/ultramafic complex located in Mann Township, approximately 47 km NE of Timmins, Ontario. Prior to hydrothermal alteration that resulted in formation of the chlorite patches, clinopyroxenite was a homogeneous, medium-grained clinopyroxene adcumulate. The abundances of major and trace lithophile elements and the compositions of magmatic clinopyroxene (augite, with average Mg number of 84.3, = 1.1, n = 80) are uniform across the section sampled. The most altered portions of clinopyroxenite consist of a total of 30 to 40% chlorite plus secondary diopsidic pyroxene with traces of spinel. Chlorite patches are, to some extent connected by very thin veins. Multiple generations of chlorite are inferred from cross-cutting relationships and variations in chlorite chemistry. Adjacent to chlorite patches, the magmatic clinopyroxene is occasionally converted to diopside. The secondary clinopyroxene is typically zoned from diopside to salite, and is characterized by very low minor element concentrations and a positive MnO-FeO correlation. Spinel in chlorite patches is iron-rich chromite. Magmatic chromite and iron-rich chromite are commonly zoned with outer rims of either ferrochromite or Cr magnetite or both. Occasionally trace amounts of copper-rich sulphides accompanied by platinum-group minerals occur only with the chlorite-clinopyroxene-spinel alteration assemblage. A proposed paragenetic sequence for the secondary minerals is based on reaction of magmatic clinopyroxene with a hydrothermal fluid during subsolidus cooling of the intrusion. The assemblage secondary clinopyroxene + chlorite ± iron-rich chromite suggests a fluid with maximum temperature of approximately 500°C.

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Eine sekundäre Klinopyroxen-Chlorit-Spinell Paragenese in Klinopyroxeniten, Mann Complex, Abitibi Belt, Ontario: Eine ungewöhnliche hydrothermale Alterationsabfolge

Zusammenfassung Kleine, dispers verteile Nester (< 1 cm) von Chlorit + sekundärem Klinopyroxen ±Spinell kommen in Klinopyroxeniten eines mafisch/ultramafischen Komplexes in Mann Township, ca. 47 km NE von Timmins, Ontario, vor. Vor der Alteration, die in der Bildung der Chloritnester resultierte, handelte is sich bei diesen Gesteinen um homogene mittelkörnige Klinopyroxen-Adkumulate. Die Verteilung der Haupt- und lithophilen Spurenelemente und die Zusammensetzung der magmatischen Klinopyroxene (Augit, mg 84.3, = l. l, n = 80) sind entlang des beprobten Profils einheitlich. Die am stärksten alterierten Klinopyroxenite bestehen aus 30-40% Chlorit plus sekundärem Diopsid und Spuren von Spinell. Die Chloritnester stehen über sehr dünne Gängchen miteinander in Verbindung. Auf Grund der Texturen und des Mineralchemismus sind mehrere Chloritgenerationen zu unterschieden. In der Nähe der Chloritnester wandelt sich magmatischer Klinopyroxen fallweise in Diopsid um. Der sekundär gebildete Klinopyroxen ist zonar gebaut (Diopsid zu Salit), weist sehr geringe Gehalte an Nebenelementen auf und ist durch eine positive Korrelation von FeO mit MnO charakterisiert. Der Spinell in den Chloritnestern ist Fe-reicher Chromit. Magmatischer und Fe-reicher Chromit sind normalerweise zoniert mit Rändern von Ferrochromit oder/und Cr-Magnetit. Spuren von Cu-reichen Sulfiden, die von PGM begleitet werden, kommen vereinzelt mit der Chlorit-Klinopyroxen-Spinell Alterationsgesellschaft vor. Die vorgeschlagene paragenetische Abfolge wird durch Subsolidus-Reaktion magmatischer Klinopyroxene mit hydrothermalen Fluiden im Zuge der Abkühlung der Intrusion erklärt. Die Vergesellschaftung von sekundärem Klinopyroxen + Chlorit ± Fe-reicher Chromit läßt auf ein Fluid mit ca. 500°C Maximaltemperatur schließen.

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Martian CO abundance from the J = 1 → 0 rotational transition: Evidence for temporal variations     

John C. Good  F. Peter Schloerb 《Icarus》1981,47(2):166-172

Mars was observed in the CO (J = 1 → 0) 2.6-mm wavelength line between 29 March and 1 April, 1980. The data were analyzed using a model atmosphere based on Viking measurements. A least-squares fit of the model to the observed line profile yielded an average CO mixing ratio of (3.2 ± 1.1) × 10^?3. This value is four times larger than that obtained by L. D. Kaplan, J. Connes, and P. Connes, 1969 (Astrophys. J.157, L187-L195) from analysis of an infrared spectrum obtained in 1967 by J. Connes, P. Connes, and J. P. Maillard, 1969 (Atlas of Near Infrared Spectra of Venus, Mars, Jupiter, and Saturn, Centre National de la Recherche Scientifique, Paris). Models of the Martian atmospheric chemistry indicate that this implied temporal variation could easily exist and that it would be due primarily to variations in the abundance of H₂O.  相似文献   

Derelict fishing nets in Puget Sound and the Northwest Straits: Patterns and threats to marine fauna     

Thomas P. Good  Jeffrey A. June  Ginny Broadhurst 《Marine pollution bulletin》2010,60(1):39-50

Derelict fishing gear remains in the marine environment for years, entangling, and killing marine organisms worldwide. Since 2002, hundreds of derelict nets containing over 32,000 marine animals have been recovered from Washington’s inland waters. Analysis of 870 gillnets found many were derelict for years; most were recovered from northern Puget Sound and high-relief rocky habitats and were relatively small, of recent construction, in good condition, stretched open, and in relatively shallow water. Marine organisms documented in recovered gillnets included 31,278 invertebrates (76 species), 1036 fishes (22 species), 514 birds (16 species), and 23 mammals (4 species); 56% of invertebrates, 93% of fish, and 100% of birds and mammals were dead when recovered. For all taxa, mortality was generally associated with gillnet effectiveness (total area, age and condition, and suspension in the water). Mortality from derelict fishing gear is underestimated at recovery and may be important for species of economic and conservation concern.  相似文献