摘要:

Measurements were made of the radio emissions (atmospherics) from a severe local storm which produced three tornadoes in west Texas on June 2, 1974. The radio data were obtained at a frequency of 58 MHz and were analyzed to determine the pulse rate and the frequency spectrum of the pulse envelopes. The pulse rate was highly variable during the largest tornado, in contrast to the smooth increase as the storm was initially building. Radar data showed a characteristic hook echo.

ISSN:0148-0227    

DOI:10.1029/JC080i030p04117

年代:1975

数据来源: WILEY

摘要:

A model has been developed for prediction of the reversible washout of SO2emitted from power plant plumes and other sources. Predictions of this computer code model compare favorably with washout measurements made during a number of controlled source experiments and four power plant experiments. An application of the model to previous experimental conditions of high background rain acidity shows that ‘negative washout’ can occur as a result of desorption of SO2from the rain below the SO2plume. Scavenging rates (cross‐plume integrated fluxes) measured during the power plant study show that the rate of deposition of sulfate was 1–5 times greater than that of SO2at distances from 0.4 to 11 km from the stack. The experimental results were applied to two very simple SO2oxidation models: one involving liquid phase (raindrop) oxidation and one considering ‘in‐plume’ oxidation. Either mechanism appears to be compatible with the observations if the SO2‐sulfate reaction half time in each case is of the order of 0.07 h. This result follows from a number of assumptions, including a reasonable washout coefficient for sulfate in the in‐plume case and equilibrium SO2washout in the

ISSN:0148-0227    

DOI:10.1029/JC080i030p04119

年代:1975

数据来源: WILEY

摘要:

It is proposed that the tidal input functions and observed tide be represented as linear combinations of a set of special orthogonal tidal functions, referred to as orthotides. These functions differ from the usual harmonic functions in that successive members represent successively more wiggliness in the linear admittance function. The tidal constants appropriate to this scheme are determined from the mean displaced products of the observed tide with the tidal input functions, as is done in the convolution method. Mean displaced products and linear orthotides were computed for the semidiurnal and diurnal gravitational tidal inputs. Results of Munk and Cartwright's analysis of 19 years of observed data from Honolulu, Hawaii, and Newlyn, England, were used to estimate the linear gravitational orthotide constants for those two places. The general decrease of magnitude with order of the estimated orthotide constants indicates that the tidal admittance is relatively smooth, as is expected. A procedure is outlined for a similar development of the bilinear tidal response. It is suggested that this orthogonal method be used for the routine analysis and prediction of tides, as it is more readily standardized and systematized than methods heretofore used.

ISSN:0148-0227    

DOI:10.1029/JC080i030p04131

年代:1975

数据来源: WILEY

摘要:

During the period 1959–1973 the La Jolla Tritium Laboratory monitored bomb‐produced tritium in surface seawater from 15 stations in the Pacific Ocean. Some 500 tritium determinations were carried out during this time. Furthermore, between 1965 and 1972 a series of subsurface samples from 49 locations in the Pacific Ocean was measured, and tritium concentrations as a function of depth were determined. The determinations had a standard error of ±4% and an uncertainty in the zero value of about 0.17 tritium unit. The most significant oceanographic conclusions that must be drawn from these data can be summarized in the following way: (1) Lateral flow along contours of constant density is the major factor controlling the tritium distribution in the surface and subsurface waters of the Pacific Ocean. Input of tritium into the water below the mixed layer occurs between 45° and 30°N and south of 60°S. The sinking of water in the mid‐Pacific at 30°N and its flow toward the equator was previously recognized from the presence of a salinity maximum below the thermocline. Our tritium measurements allow us now to estimate the southward component of the rate of this flow to be 1.3 ± 0.5 cm/s. In many other areas the tritium content of water under the mixed layer is undoubtedly also due to local sinking of surface water and subsequent lateral subsurface flow. (2) An upper limit for the coefficient of vertical eddy diffusion can be calculated from our tritium data in the eastern North Pacific gyre. This upper limit of 0.3 cm2/s is well below estimates derived by most other methods (Veronis, 1969), but it agrees well with the upper limit of 0.2 cm2/s derived by Rooth and Östlund (1972) from tritium measurements in the Sargasso Sea. Thus it appears that transport across lines of constant density is much slower than previously assumed. (3) The mean lifetime of water in the mixed layer of the North Pacific Ocean, i.e., the residence time, varies greatly with geographical location. North of 10°N the average residence time is between 9 and 15 years, depending on the assumed rate of the molecular exchange of water between atmosph

ISSN:0148-0227    

DOI:10.1029/JC080i030p04139

年代:1975

数据来源: WILEY

摘要:

In coastal marine sediments from western North America there is a continuing increase in239+240pu concentrations from the early 1950's to the present. Most of these transuranic isotopes have entered our surroundings following nuclear weapons testing from direct stratospheric fallout which went through a maximum around 1963. Since no maximum level in the sediments corresponding to the maximum stratospheric fallout was observed, another source of plutonium to these deposits was sought. It has been identified through the analyses of atmospheric aerosols as crustal rock debris transferred from the continents to the oceans by winds. A transport of soil debris, containing sorbed artificial radionuclides, to the oceans by winds and/or by rivers may explain the greater90Sr fluxes to the marine environment, compared to those of the continents, after this fission product is produced in nuclear explosions.

ISSN:0148-0227    

DOI:10.1029/JC080i030p04153

年代:1975

数据来源: WILEY

摘要:

The problem of a steady flow in the beta plane of an eastward vertically sheared stably stratified current over a shallow topography is formulated in the inviscid parameter regime, and a general governing equation and boundary conditions for the pressure field are obtained; conclusions are obtained only for an unsheared flow. For this case of an unsheared stably stratified eastward flow the mean motion and baroclinic motion may be decoupled, the mean motion obeying the barotropic vorticity equation. If the stratification is small, the baroclinic solution is obtained explicitly. The baroclinic motion has deeper water on the left near the bottom and deeper water on the right near the top in the northern hemisphere, and the opposite sense holds true for the southern hemisphere. Over a conical topography in the northern hemisphere the barotropic motion is clockwise; the baroclinic motion thus reinforces the barotropic motion near the bottom and opposes it near the top. For an unsheared current with a linear but not necessarily small stratification and an arbitrary bottom topography, an explicit solution for the flow is obtained as well as an expression for the net forces exerted by the current on the topography. By using this general solution the specific example of a north–south ridge is computed in detail. This calculation confirms the general features of the baroclinic motion which were derived for small stratificatio

ISSN:0148-0227    

DOI:10.1029/JC080i030p04163

年代:1975

数据来源: WILEY

摘要:

The areal extent of the benthic front—a continuous surface separating the cold Bottom Water and the warmer Deep Water in the Pacific—is studied on the basis of observed potential temperature and salinity profiles. The extent of the benthic front indicates spreading of the Bottom Water from the Antarctic circumpolar region into the Pacific. It is found that the Bottom Water spreads as far north as 20°N as a recognizable entity in temperature profiles. Farther north the vertical mixing between these two water masses has effectively erased the characteristics of the benthic front. A vertical diffusion and advection model has been used to calculate the mixing parameter, or scale height, for both the Deep and the Bottom Water. This parameter is unique in characterizing the potential temperature profiles, and its variation in the Pacific has been mapped. It is found that both the scale height for the Bottom Water and the thickness of the Bottom Water layer itself decrease northward. On the other hand, the scale height for the Deep Water and the thickness of the Deep Water layer both increase toward the north. Thus the scale height is related to the thickness in each of these water masses, and its systematic variation has significant implications for the nature of large‐scale mixing and circulation in the P

ISSN:0148-0227    

DOI:10.1029/JC080i030p04169

年代:1975

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JC080i030p04179

年代:1975

数据来源: WILEY