摘要:

Comparison of shear stress calculations has been made between the conventional profile method and the method proposed by Ling and Untersteiner (1974) by using the corrected drag plate measurements of the Kansas Field Program of 1968 made by the Air Force Cambridge Research Laboratories. A von Karman constant of 0.35 has been used for this comparison. The proposed method gives better stress estimates and less scatter in the roughness parameter than the conventional method.

ISSN:0148-0227    

DOI:10.1029/JC081i015p02581

年代:1976

数据来源: WILEY

摘要:

Local changes in atmospheric ozone relative to background regional changes over a period during which a small megaton nuclear weapon was detonated in tropical latitudes have been studied by using backscatter UV observations from Nimbus 4 satellite. Little change in total ozone was observed, less than might have been expected from current models of NOxcatalytic depletion. A further attempt was made to isolate changes at different levels by using derived ozone profile data from orbits intersecting the envelope containing bomb‐modified air without success because of contamination of the data on shorter wavelengths. We are led to conclude either that NOxyields have been overestimated or that there is an efficient NOx sink in the stratosphere that is not yet recognize

ISSN:0148-0227    

DOI:10.1029/JC081i015p02583

年代:1976

数据来源: WILEY

摘要:

The areal distribution of calcium carbonate in the surface sediments of the Atlantic Ocean and adjacent seas and oceans is mapped on the basis of over 1700 data points. The first‐order relation of carbonate distribution to water depth is evident in both the areal distribution and the plots of carbonate versus depth for 11 areas of the Atlantic. Superimposed on this relation are significant variations in both the 100% and the 0% CaCO3depth intercepts, analogous to the (calcite) lysocline and the (calcite) carbonate compensation depth, respectively. Variations in these critical parameters between the 11 areas are related to the three rate processes which control carbonate distributions: surface productivity, dissolution, and dilution by noncarbonate biogenic and nonbiogenic sediment. The areal distribution of carbonate in surface sediments is compared with that in sediments deposited at the end of the last glacial epoch, 18,000 yr B.P., when carbonate abundance was markedly lowe

ISSN:0148-0227    

DOI:10.1029/JC081i015p02595

年代:1976

数据来源: WILEY

摘要:

A comprehensive calcium carbonate map for the Indian Ocean surface sediments has been prepared from the analysis of about 1200 samples. The percent carbonate distribution shows the well‐known first‐order correlation with depth and hence reflects the physiographic peculiarities of the Indian Ocean. Thus on topographic highs such as most of the mid‐Indian ridge, Ninety East ridge, etc. the carbonate is high (>75%), whereas in deep areas such as the Wharton, Central Indian, Madagascar, and Somali basins the carbonate is low (<10%). Dilutions by terrigenous debris are marked in the Bay of Bengal and Arabian Sea adjacent to the Indian subcontinent and in the Mozambique Basin off southeast Africa. When the regions with significant terrigenous dilutions are excluded, certain systematic latitudinal variations in the carbonate critical depth (CCrD, depth below which less than 10% CaCO3is present) and carbonate lysocline (depth at which a significant decrease in carbonate percent occurs) superimposed on the general first‐order depth changes are evident. The CCrD is deepest in the equatorial region (10°N–10°S). Southward it gradually becomes shallow and reaches 4800–4600 m in the 20°S–30°S region and 4800 m in the 30°S–40°S region. It tends to deepen (∼4900 m) slightly in the 40°S–50°S region. The CCrD attains the shallowest level (3900 m) in the southernmost region (50°S–60°S) studied. The carbonate lysoclinal variation is in general opposite to that of the critical depths in the ocean north of 50°S and is the same as the critical depth in the 50°S–60°S region. These differences reflect the patterns of oceanic productivity and the dissolution effects of Antarctic Bottom Water. Low carbonate contents along with the presence of Antarctic diatoms and siliceous clay reported by Burckle et al. (1974) at 26°S–29°S and 60°E–64°E suggest a passage in the mid‐Indian ridge in that area for the Antarctic Bottom Water flowing

ISSN:0148-0227    

DOI:10.1029/JC081i015p02605

年代:1976

数据来源: WILEY

摘要:

The distribution of carbonate on the floor of the Pacific has been remapped on the basis of 1313 points from 80 references stored in the World Ocean Sediment Data Bank of Scripps Institution of Oceanography. Percent distribution maps and carbonate versus depth diagrams generally agree with previously published information and reflect the major controlling factors of carbonate sedimentation (depth, hydrography, fertility, and sedimentary processes). While carbonate distributions are of limited use in attempting to construct dissolution profiles, major trends are identifiable. In particular, the degree of lowering of the equatorial calcite compensation depth (CCD) together with an estimate of the differences in supply rates between the equator and the subtropical gyre can be used to estimate dissolution rate increase below the lysocline. There is considerable variation in the sharpness of the ‘CCD transition’ a concept defined here. This variation is thought to reflect both geographic differences in dissolution rate gradients and redeposition processes (carbonate, deep‐sea sediments, calcite, and compensation d

ISSN:0148-0227    

DOI:10.1029/JC081i015p02617

年代:1976

数据来源: WILEY

摘要:

Temperature‐height profilesT(Z) computed from density‐height profiles ρ(Z) usually have much smaller uncertainties than those computed from pressure‐height profilesp(Z), when ρ(Z) andp(Z) are measured with equal relative uncertainties δρ/ρ or δp/δp, respectively. For a fixed value of δp/pthe value of δT/T, the relative uncertainty in the derived temperature, is inversely proportional to the sampling‐height interval Δh, the height between successive pressure or density observations. Since δhmay vary over many orders of magnitude, the value of δT/Tderived from pressure data may vary over a range which also extends over many orders of magnitude. For temperatures computed from ρ(Z), however, the inverse dependence of δT/Tupon Δhessentially vanishes for Δhsmaller than about 1.5 km, so that for this regime of Δh, δT/T≃ δρ/ρ. A complex graph relates δT/Tto Δhand toTfor each of nine values of δp/p, i.e., 100%, 30%, 10%, 3%, …, 0.03%, and 0.01%. Another complex graph relates δT/Tto Δhand toTfor a similar set of nine values of δρ/ρ. A comparison of these two graphs demonstrates the advantages of deriving temperature‐heig

ISSN:0148-0227    

DOI:10.1029/JC081i015p02628

年代:1976

数据来源: WILEY

摘要:

The applicability and accuracy of the approximation of exponential decay in calculating residence times and transfer times are investigated by using simple models. Residence times so calculated are usually accurate to within tens of percent, while interhemispheric mixing times differ from corresponding transfer times by about a factor of 2.

ISSN:0148-0227    

DOI:10.1029/JC081i015p02637

年代:1976

数据来源: WILEY

摘要:

Observations of surface drift currents made by merchant ships are used to calculate the kinetic energy of the mean flow as well as the kinetic energy of the fluctuations, which is interpreted as eddy kinetic energy. The distribution of these properties is charted for the North Atlantic Ocean based on 1° squares and for the world oceans based on 5° squares. Both distributions show essentially the same features, namely, high values in the western boundary currents and in the equatorial current system and low values in the subtropical gyres. The ratio between mean energy and eddy energy is high (about 1 to 2) in the strong currents and low (about 1/20 to 1/40) in the central and eastern portions of the gyres. Comparing mean and eddy energies in ocean and atmosphere, it becomes apparent that eddy energies in the two systems are uncorrelated. The results are consistent with the idea that eddy motion in the ocean is generated in areas of strong mean shear flow and is subsequently distributed over the whole ocea

ISSN:0148-0227    

DOI:10.1029/JC081i015p02641

年代:1976

数据来源: WILEY

摘要:

Measurements of7Be specific activities in ground level air have been carried out at Fullerton, California, for a 23‐month period from September 1973 through July 1975. The mean specific activity observed at this relatively dry location (less than 37 cm of annual total precipitation) was 0.216 pCi/m3. From this result a mean tropospheric residence time for7Be‐bearing aerosols of 35.4 days is obtained. This result is in very good agreement with residence times obtained from earlier measurements of7Be and7Be/32P ratios in rainwa

ISSN:0148-0227    

DOI:10.1029/JC081i015p02647

年代:1976

数据来源: WILEY

摘要:

The collision and separation of waterdrops at their relative terminal velocities are shown to be accompanied by the formation of a filament of liquid between the drops. In an electric field the electric charge on the two drops after separation is a function of the filament length. The theory of Latham and Mason (1962) for the charge transfer between cloud particles in an electric fieldEat angle θ to the line of centers is applicable only to rigid spheres, whereas that of Censor and Levin (1973) uses an idealized model of waterdrops separating with a filament between them. Experimental measurements were compared with the two theories, and it is concluded that the charge transfer is adequately described byQ= αnEr2cos θ × 9 × 10−11C, where αnhas been determined for certain values of the drop radius ratioR/rand the nondimensional length of the fi

ISSN:0148-0227    

DOI:10.1029/JC081i015p02650

年代:1976

数据来源: WILEY