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1.
A study of the atmospheric circulation between equator and 60oN during the winter and summer seasons
Stefan L. Hastenrath 《Pure and Applied Geophysics》1969,77(1):207-226
Summary The mean zonal and meridional wind components and the mean mass circulation in different latitudes are discussed in relation to previous studies. Divergence and vertical motion are calculated for various latitude belts. There is evidence for a strong tropical Hadley cell with a temperate latitude indirect circulation during the winter season. During summer, the northern Hadley cell is weaker and displaced poleward; a circulation in the opposite sense appears in equatorial latitudes.The regional patterns of divergence and vertical motion appear related particularly to the position of the subtropical high pressure cells. Subsidence and lower-layer divergence are characteristic of the eastern flanks of the subtropical anticyclones, while the opposite pattern prevails on its western flanks. These longitudinal contrasts appear particularly pronounced during the summer season. The three-dimensional flow pattern in the tropics is illustrated by selected trajectories for the winter and summer seasons. 相似文献
2.
Dr. W. Schüepp 《Pure and Applied Geophysics》1955,30(1):179-181
Summary It is shown thatLinke's definition of the «subzonal» solarconstant meets best the problems of the meteorologist.Georgi's «meteorological» solarconstant neglects waveregions very important in biology and in atmospheric heating and has to be rejected. The «astrophysical» solarconstant needs further knowledge of X-rays, radio and corpuscular radiation in units of energy. 相似文献
3.
Fritz Gassmann 《Pure and Applied Geophysics》1959,43(1):83-107
Zusammenfassung Gegeben ist ein festes, elastisches Medium, das aus homogenen, isotropen, planparallelen Schichten aufgebaut ist. Im Innern einer Schicht wird ein punktförmiger Störungsherd von Multipolcharakter angenommen. Die Störung setzt zur Zeitt=0 ein. Unter Anwendung der Laplace-Transformation werden nach dem Verfahren vonCagniard «Exponentialkoeffizienten» und «Übertragungsfaktoren» berechnet, die gestatten, die elastischen Verschiebungen der an den verschiedenen Unstetigkeitsflächen reflektierten und gebrochenen Wellen zu bestimmen.
Summary (Elastic waves of multiplet type in a solid consisting of homogeneous isotropic layers with plane parallel boundaries) — An unlimited elastic solid consists of homogeneous isotropic layers, separated by plane parallel boundaries. A point in the interior of one layer is a multiple source of elastic waves. The disturbance begins att=0. By aid of Laplace-transforms, «exponential coefficients» and «transmission factors» have been calculated according to the method shown byCagniard. By aid of the «transmission factors» we can determine the elastic displacements of the waves reflected and refracted at the boundaries.相似文献
4.
Dozent Dr. Richard Fleischer 《Pure and Applied Geophysics》1953,26(1):172-182
Zusammenfassung Es wird die seit 1949 verwendete Ausführung der Strahlungsmesskugel nachLarché-Schulze beschrieben. Sie ist ausschließlich für Spektralmessungen bei gleichzeitiger Verwirklichung der Forderung der «ebenen, das Cos-Gesetz befolgenden Fläche» entwickelt worden. Um die laufende Registrierung beim Dauereinsatz im Freien zu ermöglichen, ist das Gerät durch ein heizbares Wetterschutzgehäuse und durch ein Prüfgehäuse zur Ueberwachung seines Empfindlichkeitszustandes ergänzt worden.
Summary The form of the «radiation measuring sphere» according toLarché-Schulze is discribed, it is used since 1949. It has been developed only for measuring monochromatic radiation to realize a flat surface following the cosine-law. In order to enable us to obtain continuous records in the open air, theLarché-sphere has been completed by an easily heated case protecting against bad weather and by a case controlling its sensibility.相似文献
5.
G. N. Katterfeld 《Bulletin of Volcanology》1984,47(3):531-535
An interpretation of theMariner 10 pictures shows that volcanic plains are largely developed on Mercury, and old and young lava covers can be distinguished occupying no less than 15% of the photographed surface of this planet. Ten and a half volcanic features attributable tovolcanic domes are visible on the pictures, the largest of which being situated at the centre ofOdin Planitia and having a diameter of 7 km and a height of about 1.4 km. The domes have been mapped on a geologic-morphologic map of Mercury (Katterfeld, 1975).The study of newly processed photographs of Mercury and of stereopair pictures of its volcanic «maria» has led to the discovery of a huge volcano at the centre of «Martis Mare» with 110 km long diameter and a double top caldera, the diameters of the external and internal crater being 60 and 40 km respectively. The coordinates of this volcano are 21°S and 124°W. 相似文献
6.
D. J. Schove 《Pure and Applied Geophysics》1961,49(1):255-263
Summary Pressure anomaly maps for the world for different periods have been constructed from barometric information received as a result of international appeals. Maps of changes by 5-year periods have been shown to reflect a pressure see-saw between West Greenland and the Indian Ocean. The sign of this pattern is defined by the «pressure parameter», approximately the reversed pressure in the latter area. The parameter seems to represent much more reliably than sunspot numbers the effective changes in solar radiation. Changes by 30-year periods, at least between 1876/1905 and 1906/35, follow a geographical pattern very similar to that of the ordinary southern oscillation, with at least one marked «discontinuity» in the nodal zone off south-east Australia. In contrast to the map of changes by five-year periods, West Greenland now acts as a negative area, that is, its pressure fluctuates in sympathy with the Indian Ocean. However, there is a phase difference, associated with «south-steering», and a difference of wave-length between the Arctic and the Tropics, and historical evidence suggests that Greenland can also be a «positive» area. In low latitudes, the major pressure oscillation has for over a century been closely in phase with the major sunspot oscillation, that is, an oscillation of the order of 60 to 90 years. A sudden change to low parameter phase in the next decade or so is therefore expected. This will be associated presumably with severe droughts in many low latitude regions and the characteristic changes in circulation patterns. 相似文献
7.
Dr. Peter Mauersberger 《Pure and Applied Geophysics》1964,57(1):143-148
Zusammenfassung Die Kinematik der magnetischen Feldlinien im Plasma kann mit denselben mathematischen Hilfsmitteln studiert werden, welche sich in der Kinematik der Wirbel bewährt haben. Ausgehend vom Faradayschen Induktionsgesetz für bewegte Medien können gefolgert werden: eine notwenige und hinreichende bedingung dafür, dass die magnetischen Feldlinien mit materiellen Kurven zusammenfallen; ein Analogon zuC. Truesdells «basic vorticity formula», welches die Mitführung und Diffusion der magnetischen Feldlinien im Plasma beschreibt; Sätze zur Kinematik der Feldlinien, welche eine frei wählbare tensorielle Feldfunktion beliebiger Stufe enthalten und den vonH. Ertel formulierten «allgemeinen Wirbelsätzen» entsprechen, insbesondere Analoga zuErtels «Vertauschungsrelationen». In einem isentropen idealen Plasma ist das mit dem spezifischen Volumen multiplizierte Skalar-produkt aus der magnetischen Induktion und dem Gradienten der Entropiedichte zeitlich individuell konstant.
Herrn ProfessorDr. Hans Ertel zum 60. Geburtstag in Dankbarkeit gewidmet. 相似文献
Summary The kinematics of magnetic field lines in a plasma can be studies by means of the mathematical methods used in the kinematics of vorticity. Starting withFaraday's law of induction for moving circuits the following results can be derived: a necessary and sufficient condition that the magnetic field lines remain material lines; a formula describing the convection and diffusion of the magnetic field lines in a plasma, which is analogous to the «basic vorticity formula» ofC. Truesdell; general theorems containing an arbitrary tensor field of any order, which are analogous to general vorticity theorems ofH. Ertel, especially a «commutation formula» corresponding to the «Euler-Ertel commutation formula» for circulation preserving motions. Given an isentropic ideal plasma it follows that ( denoting the density, the magnetic induction,s the specific entropy, andd/dt the material time derivative).
Herrn ProfessorDr. Hans Ertel zum 60. Geburtstag in Dankbarkeit gewidmet. 相似文献
8.
Using over 2200 ozonesonde ascents, published byHering andBorden [1]–[5] and byDütsch
et al. [6], [7], the average vertical distribution of the ozone mixing ratio is found for different latitudes and for different seasons up to a height of 30 km. The method by which the ozone formed at great heights in low latitudes becomes concentrated in the lower stratosphere of high latitudes is discussed, and the meridional circulation theory is strongly suggested.Oxford, May 1972. 相似文献
9.
Dr. J. -C. Heuberger 《Pure and Applied Geophysics》1956,34(1):71-73
Résumé Des mesures de températures ont été faites dans les Forages du Camp VI et de la Station Centrale, au cours de la Campagne de 1950, des « Expéditions Polaires Françaises 1948–1951 ». Ces mesures ne concordant pas avec celles effectuées par « L'Expédition Allemande au Groenland, A.Wegener, de 1930–31 », le ProfesseurKurt Wegener, dans un rapport intitulé « Température de l'Inlandsis du Groenland », commente les résultats, et, utilisant les résultats des deux Expéditions, établit la distribution de la température dans l'Inlandsis. — Le but de ce rapport est de justifier les mesures de 1950, de donner une limite d'utilisation de ces mesures, et d'expliquer les divergences entre les résultats des deux Expéditions.
Summary In the drilled holes of Camp VI and «Station Centrale», temperature surveys were run during the 1950th expedition of «French Polar Expeditions 1948–1951» (MissionsPaul-Emile Victor). The measurements not being in agreement with those made by the «German Expedition to Greenland A.Wegener 1930–1931» Professor Dr.Kurt Wegener, in a report published in this revue (Die Temperatur in Grönländischen Inlandeis), comments the results and, using the results of both expeditions, gives the temperature distribution in the Greenland Ice-Cap. — The purpose of this report is to justify the 1950th surveys, to state the readings accuracy and to find out the causes of the divergences between the results of both expeditions.相似文献
10.
Rudolf Eyfrig 《Pure and Applied Geophysics》1959,44(1):179-187
Zusammenfassung Messwerte russischer Stationen beweisen die Existenz eines «Kontinental-Effektes» bei der maximalen Elektronendichte derF2-Schicht. Im Sommer besteht im Innern des asiatischen Kontinents vorzugsweise eine höhere Konzentration bei Tag; andererseits fehlt dort die sogenannte «Abend-Konzentration».
HerrnJulius Bartels zum sechzigsten Geburtstag gewidmet. 相似文献
Summary Results from Russian stations prove the existence of a «Continental effect», on the Maximum electron density of theF2-layer. In summer, in the interior of the asiatic continent a tendency exists for a higher concentration in daytime; on the other side the so-called «evening concentration» is missing there.
HerrnJulius Bartels zum sechzigsten Geburtstag gewidmet. 相似文献
11.
Dipl. Meteor. Martin Franke 《Pure and Applied Geophysics》1951,20(1):87-130
Zusammenfassung Es werden tägliche Gänge des Austauschkoeffizienten an zwei Stationen, Leafield (England) und Ismaila (Aegypten), die jeweils einen bestimmten Klimatyp repräsentieren, mit und ohne Berücksichtigung des Turbulenzcharakters berechnet. Die Berücksichtigung des Turbulenzcharakters (in erster Näherung in Abhängigkeit von Strahlung und Wind) führt zur charakteristischen Auswahl, z. B. zum Konvektionstyp, Stratustyp, die Nichtberücksichtigung zur klimatologischen Auswahl. Beide Auswahlen werden miteinander verglichen und Kriterien über ihre Anwendung festgelegt. Zusätzlich werden die jährliche Variation betrachtet und die Gänge in empirisch- analytische Funktionen zerlegt. Als Grundlage zur Berechnung dienen die Temperatur- bzw. Temperaturgradientregistrierungen vonN. K. Johnson undG. S. P. Heywood (7) über 5 Jahre in 5 Niveaus (1.2, 2.4, 30.4, 57.4, 87.7 m, Leafield) und die vonW. D. Flower (8) über ein Jahr in 4 Niveaus (1.1, 16.2, 46.4, 61.0 m, Ismaila). Es wird gezeigt, dass der lineare Höhenansatz für den Austauschkoeffizienten, der für eine adiabatische Atmosphäre gilt, nicht auf eine wirkliche Atmosphäre angewandt werden darf; als ein günstiger Ansatz wurde im Höhenintervall von 10–100 m dasGauss'sche Fehlerintegral gefunden, der durch die Berechnung der Austauschkoeffizienten in zwei Messtufen für Leafield geprüft werden kann; die bisherigen Berechnungen beschränkten sich auf eine Meßstufe und ergaben keine Möglichkeit, den Ansatz zu prüfen. Dieser Höhenansatz ergibt einen stetigen Uebergang von der Boden- zur Oberschicht, oder anders ausgedrückt, von der Schicht mit höhenabhängigem Austausch zu der mit höhenkonstantem, so erhält man die vonC. G. Rossby (9) eingeführte Restturbulenz (residual turbulence). Es werden tägliche Gange des Austauschkoeffizienten im einzelnen diskutiert; besonders der Spezialfall der klaren Junitage von Leafield (Konvektionstyp der gemässigten Breiten), für den eine Modellvorstellung entworfen wird, bei der die Wechselwirkung von Strahlung, Schichtung, Temperatur und Austausch gleichzeitig betrachtet wird.Ausgehend von der zweiten Diffusionsgleichung des atmosphärischen Austauschs wird gezeigt, dass sowohl für den Austausch als auch für das Integral der Diffusionsgleichung die Trennung der Variablen möglich ist mit der Einschränkung, dass bei Tagen bzw. Auswahlen von Tagen mit ausgesprochenem täglichen Gang für Tag und Nacht verschiedene höhenfunktionen erforderlich sind. Die beiden separaten (gewöhnlichen) Differentialgleichungen, die nach der Trennung der Variablen erhalten wurden, werden vorerst getrennt integriert und die Konstanten jeweils voneinander unabhängig berechnet; damit erhält man einerseits die Möglichkeit, die durch Integration der Zeitabhängigkeit des Austauschkoeffizienten erhaltene neue Zeitfunktion mit der der gegebenen potentiellen Temperatur zu vergleichen, andererseits den Höhenansatz ein zweitesmal zu prüfen. Die numerische Prüfung der Zeitabhängigkeit wurde für die Auswahl «Alle Junitage Leafield», die der Höhenabhängigkcit für die Auswahl «Bedeckte Dezembertage Leafield» durchgeführt. Abschliessend werden die beiden Gleichungen zusammen betrachtet, die Integration vorgenommen, eine numerische Auswertung jedoch nicht ausgeführt.
Summary The daily variation of the «Austauschkoeffizient», i. e. eddydiffusivity, has been computed for two stations, Leafield (England) and Ismaila (Egypt), representing each other a special type of climate. On the side one attention has been given to the character of turbulence as mainly influenced by insolation and wind leading to a characteristic selection, for instance a «convection-type»; on the other side normal monthly values have led to a climatologic selection. Both selections have been compared and criterions for their use determined. Additionally the daily variations have been analysed in known functions, their annual variations regarded.The foundations for this analysis were the registrations of temperature or temperature-gradient ofN. K. Johnson andG. S. P. Heywood for 5 years at 5 levels (1.2, 12.4, 30.5, 57.4, 87.7 m, Leafield) andW. D. Flower for 1 year at 4 levels (1.1, 16.2, 46.4, 61.0 m, Ismaila).A main result is that the linear function with height of the «Austauschkoeffizient», confirmed for an adiabatic atmosphere, cannot be applied to a real atmosphere; the error-function integral has been found a good approximation in the interval between 10 and 100 m, which can be tested by computing the daily variation of the «Austausch-koeffizient» at two levels; previous results were limited to a single level without this possibility of testing. This variation with height gives a steady transition from the layer with variable «Austauschkoeffizient» to the one with constant «Austauschkoeffizient» thus getting the residual turbulence ofC. G. Rossby. Special types of the daily variation of the «Austauschkoeffizient» have been discussed, especcially the convectiontype of middle latitudes (Leafield, clair days), for which a model has been given, regarding the mutual effects of insolation, gradient, temperature and «Austausch».Basing on the second partial differential equation of atmospheric diffusivity it has been shown that both for the «Austauschkoeffizient» and the integral of this equation the separation of the two variables (t=time,z=altitude) is possible with the limitation that for days respectively selections of days with great daily variation different functions with height for day and night are necessary. This resulted in getting two ordinary differential equations, which at first have been integrated separately, and so determined their constants. Now it was possible to compare the daily variation of the integral with that of the given potential-temperature, additionally to prove the function with height for a second time. A numerical proof for the daily variation has been made for the selection «all days of june, Leafield», for the function with height for the selection of «covered days of december, Leafield». Finally both differential equations have been considered together, a numerical example has not been given for special reasons.相似文献
12.
13.
Dott. Ing. Agatino D'Arrigo 《Pure and Applied Geophysics》1948,11(1):101-121
Riassunto L'ubicazione dell'antico cordone litorale, che ridossava l'Emporio di Medma (VIo secolo avanti Cristo) in Magna Grecia, è messa in correlazione con il veto geologico posto dall'Ing.Cortese all'eventuale costruzione di nuove opere marittime lungo il litorale tirrenico della Calabria meridionale e con l'incrementato ritmo di denudazione e di dispersione del terreno agrario nell'epoca moderna.
Summary The site of the ancient littoral bank, that protected the Medma's Emporium (VIth century before Christ) in Magna Graecia, is placed in correlation with the geological «veto», established by the EngineerCortese at the eventual construction of new maritime works along the tirrenic littoral of the meridional Calabria and with the increased rhythm of denudation and of dispersion of the agrarian soil in the modern epoch.相似文献
14.
Dr. Hans Ulrich Roll 《Pure and Applied Geophysics》1952,21(1):110-126
Zusammenfassung Eineabsolute «kritische Windgeschwindigkeit» für Prozesse an der Grenzfläche Wasser-Luft scheint nicht zu existieren. Unsere Beobachtungen liefern jedoch Anzeichen für das Vorhandenseinrelativer «kritischer Windgeschwindigkeiten, die vom Ueberströmungsweg, bzw. von der Wellenlaufstrecke abzuhängen scheinen. Diese relativen «kritischen Windgeschwindigkeiten» sind durch folgende-Merkmale gekennzeichnet: Aenderung der Struktur der Meeresoberfläche (glatt-rauh); Umschlag der laminaren Wassergrenzschicht zur Turbulenz; Ueberbrechen der Schwerewellen; Minimum des Widerstandskoeffizienten der Meeresoberfläche.
Summary It seems that there is no absolute «critical wind speed» for air-sea boundary processes. From our observations it may, however, be referred that there are relative values of the «critical wind speed» which seem to depend on the fetch. These relative values of the «critical wind speed» are characterized by the following marks: The sea surface pattern is changed (smooth-rough);, the boundary layer in water turns from laminar to turbulent flow; the gravity waves break; the resistance coefficient of the sea surface has a minimum.相似文献
15.
On the mean zonal and meridional circulations and the flux of moisture in the northern hemisphere during the summer season 总被引：6，自引：0，他引：6
Summary The mean zonal and meridional wind components of the northern hemisphere at different pressure levels for the summer season June–August have been determined and the mean meridional mass circulation has been computed as a function of latitude. From the mass circulation the meridional flux of moisture is computed for the latitudinal belt 0°–45° N. Using the horizontal divergence of this flux the average difference between precipitation and evapotranspiration from the earth's surface is evaluated. 相似文献
16.
Dr. Tsuneji Rikitake 《Pure and Applied Geophysics》1953,26(1):30-40
Summary A general theory of a time-dependent magnetic dipole in the earth is discussed. On the basis of the weastward drift of the «equatorial» dipole in the two eccentric dipoles model due toH. G. Macht, the impossibility of the origin of geomagnetic secular variation being in a deep interior of the earth's core is established from the standpoints of the shielding effect and the motions in the core. But the westward drift of the core's top layer relative to the mantle seems to be quite reasonable, even if we take into account the shielding effect of the mantle. 相似文献
17.
Martin Franke 《Pure and Applied Geophysics》1949,14(1-2):120-131
Zusammenfassung Die vonJ. G. Brown vertretene Auffassung, den doppelperiodischen Tagesgang des luftelektrischen Potentialgefälles an Landstationen als Ueberlagerung eines einfach- periodischen Ganges und einer austauschbedingten Depression darzustellen, wird mit Hilfe berechneter Tagesgänge des Austauschkoeffizienten quantitativ bestätigt.
Herrn Prof. Dr.W. Peppler zum 65. Geburtstag gewidmet. 相似文献
Summary Following a suggestion ofJ. G. Brown of regarding the local variation of the earth's electric field at land-stations as mainly caused by the cycle of turbulence, convection, and subsidence the problem of the double-period of the daily variation of the earth's electric field has been numerically solved. By computed values of the daily variation of the «Austauschkoeffizient», an exact measure of atmospheric turbulence, basing on temperature observations of Leafield (England) for clear days, the daily variation of nuclei has been computed for; thus getting additionally the daily variation of ions, conductivity, and local potential-gradient. Combining this computed variation of the potential-gradient and the unitary variation of the earth's field over oceans shows a double-period (local time) of the potential-gradient of the earth's electric field at land-stations. Thus the problem of the double-period of the daily variation of the earth's electric field has been reduced to one of a single-period which cannot be explained by the «Austausch».
Herrn Prof. Dr.W. Peppler zum 65. Geburtstag gewidmet. 相似文献
18.
Summary The geomagnetic records obtained at Genova during the eclipse of February 15th, 1961 are quantitatively interpreted with the aim of separating the eclipse effect. Using the ionospheric observations also made at Genova, the result is well confirmed by the calculations carried out applying both theChapman-model and theVolland-scheme for estimating the geomagnetic effect as originated by the changes of the current system flowing in theE-layer.This report belongs to a set of investigations on geophysical effects of the solar eclipse of February 15th, 1961 carried out by the «Istituto Geofisico, Università di Genova», and made possible through a financial support of the «Consiglio Nazionale delle Ricerche». 相似文献
19.
The circulation of the Southern Ocean is studied in the eddy-resolving model POP (Parallel Ocean Program) by an analysis
of zonally integrated balances. The TEM formalism (Transformed Eulerian Mean) is extended to include topography and continental
boundaries, thus deviations from a zonally integrated state involve transient and standing eddies. The meridional circulation
is presented in terms of the Eulerian, eddy-induced, and residual streamfunctions. It is shown that the splitting of the meridional
circulation into Ekman and geostrophic transports and the component induced by subgrid and Reynolds stresses is identical
to a particular form of the zonally integrated balance of zonal momentum. In this balance, the eddy-induced streamfunctions
represent the interfacial form stresses by transient and standing eddies and the residual streamfunction represents the acceleration
of the zonal current by density fluxes in a zonally integrated frame. The latter acceleration term is directly related to
the surface flux of density and interior fluxes due to the resolved and unresolved eddies. The eddy-induced circulation is
extremely vigorous in POP. In the upper ocean a shallow circulation, reversed in comparison to the Deacon cell and mainly
due to standing eddies, appears to the north of Drake Passage latitudes, and in the Drake Passage belt of latitudes a deep-reaching
cell is induced by transient eddies. In the resulting residual circulation the Deacon cell is largely cancelled and the residual
advection of the zonal mean potential density is balanced by diapycnal eddy and subgrid fluxes which are strong in the upper
few hundred meters but small in the ocean interior. The balance of zonal momentum is consistent with other eddy-resolving
models; a new aspect is the clear identification of density effects in the zonally integrated balance. We show that the wind
stress and the stress induced by the residual circulation drive the eastward current, whereas both eddy species result in
a braking. Finally, we extend the Johnson–Bryden model of zonal transport to incorporate all relevant terms from the zonal
momentum balance. It is shown that wind stress and induction by the residual circulation carry an eastward transport while
bottom form stress and the stress induced by standing eddies yield westward components of transport.
Received: 26 June 2001 / Accepted: 2 November 2001 相似文献
20.
Professor J. T. Whetton D.S.O. O.B.E. M.C. T.D. M.Sc. J. O. Myers B.Sc. A.M.I.Min.E. I. J. Watson B.Sc. Ph.D. 《Pure and Applied Geophysics》1955,32(1):43-53
Summary Observations of gravity over the Palaeozoic rocks of East Carmarthenshire show this to be an area of positive Bouguer anomalies, and throughout the district the isogams are aligned in a «Caledonoid» direction. The regional gradient over the anthracite coalfield can largely be explained in terms of known structure, while the anomaly values in the Towy valley above Llandeilo seem to have been affected by facies variations and contemporaneous volcanic activity. Fairly large anomalies are recorded near Carmarthen, and these may be associated with similar anomalies known near Aberystwyth (Cook & Thirlaway, 1950); they are interpreted as an expression of the Welsh geosyncline. The gravity low discovered in St. George's Channel byBrowne & Cooper (1950) is re-interpreted in terms of the depth of the pre-Palaeozoic floor. There is no marked evidence to indicate the presence of a concealed «granitic» intrusion beneath the coalfield, nor to substantiate the view that there was once a great thickness of Permian or later cover. 相似文献