摘要:

Stratospheric aerosol has been collected by means of filters borne by both balloons and aircraft. The sulfate concentrations are higher than those observed by means of impactors. Ammonium sulfate or persulfate were not major constituents of these samples. Concentrations in the tropical stratosphere were not significantly higher than those found in midlatitudes. The data are discussed with respect to optical observations of the stratospheric aerosol layer during this period. Preliminary18O/16O and34S/32S measurements for stratospheric sulfate are given.

ISSN:0148-0227    

DOI:10.1029/JC076i033p08083

年代:1971

数据来源: WILEY

摘要:

High‐precision continuous temperature profiles and detailed hydrographic data from the central North Pacific are interpreted as showing the existence of a narrow eastward bottom current. This current flows along the southern flanks of the mid‐Pacific mountains, through a deep passage 10 km wide south of Horizon guyot and on around the southeastern end of the Hawaiian chain. The deviations of the abyssal water temperature profiles from normal adiabatic type to highly subadiabatic are evidence of the continuous input of a cold bottom water layer. Abrupt changes in the vertical gradients of temperature and dissolved constituents mark the boundary between the Bottom Water and the Deep Wa

ISSN:0148-0227    

DOI:10.1029/JC076i033p08089

年代:1971

数据来源: WILEY

摘要:

Computations were made for water mass exchange at the mouth of the Gulf of California based on a model that takes into consideration only geostrophic flow with a reference level adjusted to obtain agreement between inflow and outflow. These data were restricted to three cruises that obtained hydrographic information about the deep waters. The minimum transports are estimated from 2.57 to 3.65 Sv.

ISSN:0148-0227    

DOI:10.1029/JC076i033p08098

年代:1971

数据来源: WILEY

摘要:

Marked step‐like structure exists in vertical profiles of temperature and salinity obtained in the Arctic Ocean. This structure occurs between 200 and 500 meters depth, where both temperature and salinity increase with depth. Nominally, the structure consists of thin sheets (0.1 meter thick) separating adjacent homogeneous layers (3 meters thick) that differ in temperature by 0.02°C and in salinity by 0.01‰. While the step structure is quite persistent, its character varies markedly with depth. Intermediate layers have been observed, as well as noncoincident temperature and salinity gradient sheets. Analysis of the data lends support to the hypothesis that this type of layering arises from the double‐diffusive p

ISSN:0148-0227    

DOI:10.1029/JC076i033p08107

年代:1971

数据来源: WILEY

摘要:

Airgun reflection profiles indicate that the relict Aleutian abyssal plain consists of two tongues of well‐stratified sediments deposited from turbidity currents which entered the region from a northerly direction. The distribution of the turbidites appears to have been largely governed by a topographic grain imparted to the basement surface by Late Cretaceous‐Paleocene plate motions associated with the generation of the Great Magnetic Bight. High resolution 3.5 kHz sub‐bottom profiles and sedimentation rate data suggest that the last channelized routes of turbidity current flows to the southern portion of the area were severed during the Late Miocene, 6.9 (±0.9) m.y. ago, and since then only pelagic sediments have accumulated. The change in the depositional regime can thus be associated in time with the change in the direction of sea‐floor spreading in the northeastern Pacific and to the start of a period of severe deformation in southern Alaska. The pattern of sedimentation and the time at which the Aleutian plain became isolated from its source of terrigenous sediments are both consistent with models recently proposed for plate motions in the northeastern Pacific since the close of the Mesozoic. The present sedimentary data are not sufficient, however, to determine whether large relative motions between the Pacific and North American plates may have occurred during Terti

ISSN:0148-0227    

DOI:10.1029/JC076i033p08121

年代:1971

数据来源: WILEY

摘要:

Instrumental activation analyses for 16 major and trace elements in a suite of mid‐Atlantic ridge basalts reveals that the slowly cooled interior portions of these submarine extrusions are depleted, relative to the quenched flow margins, in several elements that are enriched in pelagic sediments and manganese nodules (Mn, Fe, Co, the rare earth elements, and others). Many of these elements are excluded from the solid phases that crystallize from the melt, and thus are concentrated in residual liquids. Additional elements are mobilized during the deuteric alteration of early‐formed olivine and the formation of immiscible sulfide liquids. It is suggested that these components of melt occupy accessible sites (e.g., intergranular boundaries) in the hot solid rock mass, and are mobilized by dissolution as chloride complexes in sea water introduced along contraction cracks that form during cooling and solidification. These solutions may be the metal‐bearing ‘hydrothermal exhalations’ or ‘volcanic emanations’ that accompany submarine volcanism, which are often cited as a source of metals into the pelagic environment. Reasonable estimates of the amount of material involved suggest that a significant fraction of the mass of these elements that reside in pelagic sediments could have been supplied by this process. Recently described amorphous iron‐manganese‐silica material from the east Pacific rise may form by direct precipitation from these hydrothermal solutions following their introducti

ISSN:0148-0227    

DOI:10.1029/JC076i033p08128

年代:1971

数据来源: WILEY

摘要:

An experiment to monitor the ozone concentration in the upper stratosphere and lower mesosphere was performed at the Panama Canal Zone (9°20′N, 79°59′W) during the first two weeks in November 1970. The rocket‐borne ozonesonde, a self‐pumping device that incorporated a temperature‐sensing bead thermistor on a time‐sharing basis with the ozone sensor, was used for this study. Two electrochemical ozonesondes (Mast type) with the AMT‐12 Radiosondes were flown on balloons, one on November 9 and the other on November 12, 1970. The temperature and ozone data from the tests are presented. An increase in ozone number density was measured (2.4×1016mol/m3to 7.0×1016mol/m3) at a 50‐km altitude from d

ISSN:0148-0227    

DOI:10.1029/JC076i033p08139

年代:1971

数据来源: WILEY

摘要:

Measurements of N2O concentration in air and water from the North Atlantic Ocean show the surface waters to be supersaturated with respect to the atmosphere, which suggests production and a source for atmospheric N2O. In deep waters the N2O concentration was less than atmospheric equilibrium, which indicates slow decomposition.

ISSN:0148-0227    

DOI:10.1029/JC076i033p08143

年代:1971

数据来源: WILEY

摘要:

A series of experiments on turbulent diffusion were conducted in Lake Michigan by using fluorescent dye as the tracer of water movement. The observed rates of growth of diffusing material under normal conditions agree well with Batchelor's (1950, 1952) theoretical results concerning relative diffusion in a field of homogeneous turbulence. The effective eddy diffusivity is computed from field measurements of the mean dispersion of the tracers. Results show that the lateral (cross stream) eddy diffusivity is in the order of 103cm2/sec and the longitudinal (along stream) eddy diffusivity is about four to five times greater. Since the eddy diffusion processes are accelerated by other factors, such as the shearing flow and the unsteady current, these experimental values of eddy diffusivity, measured under relatively calm conditions, may be considered as representative of the lower range for Lake Michigan.

ISSN:0148-0227    

DOI:10.1029/JC076i033p08147

年代:1971

数据来源: WILEY

摘要:

The lowering of surface temperature below that of the water temperature underneath a floating sea‐ice sheet often results in thermal cracking. The formation of these cracks is investigated theoretically by modeling the ice sheet as a floating elastic plate with thermal properties that vary with temperature and salinity. Results are obtained by extending previous work of Evans and Untersteiner and a typical crack spacing on the order of 200 m is found for perennial sea ic

ISSN:0148-0227    

DOI:10.1029/JC076i033p08153

年代:1971

数据来源: WILEY