Possible ecosystem impacts of applying MSY policies from single-species assessment   总被引：11，自引：1，他引：11  

Walters  Carl J.; Christensen  Villy; Martell  Steven J.; Kitchell  James F. 《ICES Journal of Marine Science》2005,62(3):558-568

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Side-scan sonar as a tool for mapping spatial variations in sediment type     

Carl H. Hobbs 《Geo-Marine Letters》1985,5(4):241-245

Studies with increasing sample densities over a common area demonstrate that the distribution of estuarine sediment types varies on several scales. The variations and accompanying steep gradients in the characteristics of the sediments may lead to different interpretations of the dynamics of estuarine depositional processes depending on the scale examined. Field work in parts of Chesapeake-Bay and the York River Estuary, Virginia indicates that the spatially continuous data on the nature of the bottom surface available with side-scan sonography offers a means of assessing the continuity of sediment type.  相似文献   

Management options for the Blackwater herring, a local spring-spawning stock in the Thames Estuary   总被引：1，自引：3，他引：1  

Roel  Beatriz A.; O'Brien  Carl M.; Basson  Marinelle 《ICES Journal of Marine Science》2004,61(3):297-307

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High altitude infrared spectroscopic evidence for bound water on Mars     

J.R. Houck  James B. Pollack  Carl Sagan  David Schaack  John A. Decker 《Icarus》1973,18(3):470-480

The reflectivity of the Martian surface has been measured between 2.0 and 4.0 μ. A broad absorption band is observed which has a minimum at 2.85μm. The position and shape of the band is compared to features in numerous terrestrial minerals. Bound water in the Martian surface material is the most likely cause of the observed band. The strength of the observed band suggests a bound water content of approx. 1% by weight. The band is inconsistent with > a few % limonito or hydrated polymeric carbon suboxide. A mean particle radius ～100μm is deduced. The quality of bound water derived has a range of geological, climatic, and exobiological implications  相似文献   

Geology of the Moon: revised edition. Thomas A. Mutch. Princeton University Press, 1973. 391 pp. Price $22.50     

Carl Sagan 《Icarus》1973,20(1):123-124

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The greenhouse of Titan     

Carl Sagan 《Icarus》1973,18(4):649-656

Both non-gray radiative equilibrium and gray convective equilibrium calculations for Titan indicate that the discrepancy between the equilibrium temperature of an atmosphereless Titan and the observed infrared temperatures can be explained by a massive molecular hydrogen greenhouse effect. The convective calculations indicate a probable minimum optical depth of 14, corresponding to many tens of km-atm of H₂, and total pressures of ～0.1 bar. The tropopause is several hundred km above the Titanian surface and at a temperature of about 90°K. Methane condensation is likely at this level. Such an atmosphere is unstable against atmospheric blow-off unless typical mesosphere scale heights are < 25km, an unlikely situation. Blow-off can also be circumvented by exospheric temperatures near the freezing point of hydrogen. It is considered more plausible that the present atmosphere is in equilibrium between outgassing and blow-off of the one hand and accretion from protons trapped in a hypothetical Saturnian magnetic field on the other; or exhibits uncompensated blow-off of outgassing products. To maintain the present blow-off rate without compensation for all of geological time requires an outgassing equivalent to the volatilization of a few km of subsurface ices. Photo-dissociation of these volatilized ices produces the observed high abundance of H₂ as well as large quantities of complex organic chromophores which may explain the reddish coloration of the Titanian cloud deck. An extensive circum-Titanian hydrogen corona is postulated. Surface temperatures as high as 200°K are not excluded. Because of its high temperatures and pressures and the probable large abundance of organic compounds, Titan is a prime target for spacecraft exploration in the outer solar system.  相似文献   

A STUDY OF POPULATION INCREASE IN THE GREATER KUZNETSK REGION,U.S.S.R., 1897–1966, AS SHOWN BY GROWTH OF CITIES GREATER THAN 50,000 IN 1966*     

Carl F. Ojala 《The Professional geographer》1968,20(5):303-312

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The new Martian nomenclature of the international Astronomical Union     

G. de Vaucouleurs  J. Blunck  M. Davies  A. Dollfus  I.K. Koval  G.P. Kuiper  H. Masursky  S. Miyamoto  V.I. Moroz  Carl Sagan  Bradford Smith 《Icarus》1975,26(1):85-98

A new nomenclature for Martian regions and topographic features uncovered by Mariner 9, as officially adopted by the International Astronomical Union, is described. About 180 craters, generally of diameters >100 km, have been named, as well as 13 classes of topographic features designated catena, chasma, dorsum, fossa, labyrinthus, mensa, mons, patera, planitia, planum, tholus, vallis, and vastitas. In addition seven craters and the Kepler Dorsum are named on Phobos, and two craters on Deimos. Coordinates and maps of each named features are displayed.  相似文献   

Thermal migration of water on the Galilean satellites     

Norman G. Purves  Carl B. Pilcher 《Icarus》1980,43(1):51-55

We have modeled the thermal migration of water on the Galilean satellites under the assumption of ballistic molecular trajectories. We find that water migrating owing to solar radiation on an ice-covered satellite will build up in the temperate latitudes, in general not reaching the poles. As much as 50 m of ice may have been lost by this process from the equatorial regions of Europa over the age of the solar system. The disappearance of patches of ice—for instance, the bright rays surrounding some impact craters—from the equatorial regions of Ganymede and Callisto may approach a value (the irreversible evaporation rate) three orders of magnitude larger than the net equatorial loss rate for ice-covered Europa. The presence of water ice pole caps on Ganymede extending to the latitudes at which thermal migration becomes important suggests that some process distributed an extensive, thin covering of water on the satellite, and that the equatorial regions were subsequently cleared by the thermal process.  相似文献   

Bemerkungen zum Atlantischen Problem,geäußert im Anschluß an die drei ozeanographischen Beiträge     

Carl Troll 《International Journal of Earth Sciences》1939,30(3):384-386

Ohne Zusammenfassung  相似文献