摘要:

The system of second‐order nonlinear differential equations that governs atmospheric electric variables is solved numerically for various values of the strength parameter in an expression for the eddy diffusivity. The solutions show that the atmospheric electric variables are sensitive to changes in the diffusivity and therefore can be used to determine the eddy diffusivity. The numerical results make it possible to determine the diffusivity either from electric field profile measurements or from surface measurements of field and space charge. Data taken over the open ocean are used to demonstrate the usefulness of the method. Ground radioactivity and radioactive gas emissions from the soil make it extremely difficult to apply the same technique over land area

ISSN:0148-0227    

DOI:10.1029/JC076i006p01467

年代:1971

数据来源: WILEY

摘要:

A hyperbolic system with five VHF receivers is used to obtain three‐dimensional fixes of sferics as a function of time. Data recorded during one complete flash and parts of several others have been reduced. The integrated picture of one lightning flash shows a ‘waist’ region of minimum cross section between 3.8 and 4.5 km high. Branching extends upward and downward from the waist. Downward branches do not always emerge from the cloud base. Lower regions of previously established channels tend not to radiate during high‐order strokes. By far the greater part of the activity is confined to the cloud. The flash pervaded a volume 3×4×6 km. The instrument is particularly useful for tracking interstroke processes, higher regions of a flash to ground, and cloud flashes, but the accuracy of fixes obtained below the cloud is degraded by poor height resolution in this region. Noise is sometimes emitted by clouds that are not cumulonimbus. The method used to calculate the positions of the sferic sources is described, and the accuracy of the system is

ISSN:0148-0227    

DOI:10.1029/JC076i006p01478

年代:1971

数据来源: WILEY

摘要:

In this paper atmospheric [O2(1Δg)] calculations of based on laboratory rate coefficients for the several processes of possible importance are described. The calculations are in accord with experimental observations. Even when solar radiation is strongly attenuated at λ3100 A in the interpretations of the infrared atmospheric band of the airglow in the lower regions of the stratosphere. It may also be necessary to allow for this process in the explanation of twilight observations

ISSN:0148-0227    

DOI:10.1029/JC076i006p01490

年代:1971

数据来源: WILEY

摘要:

The full set of thermo‐hydrodynamic equations, averaged in time, longitude, and height, governing the north‐south variations of the climatic variables are combined with parameterizations for the vertical flux of heat and momentum at the surface and closure formulas suggested by baroclinic and barotropic wave theory for the horizontal transient eddy transports. The complete system is integrated for surface and radiative conditions of the northern hemisphere in winter and summer. Modeling approximations are used to represent the vertical variations of the variables. The steady‐state solution obtained yields the distributions of the mean temperature, wind, humidity, precipitation, evaporation, heat balance, transient eddy statistics (i.e., the eddy kinetic energy of the meridional wind and the meridional transport of sensible heat, momentum, and water vapor), and the energy integrals. These theoretical results are a good first approximation to the observed v

ISSN:0148-0227    

DOI:10.1029/JC076i006p01498

年代:1971

数据来源: WILEY

摘要:

Recently a new model for the normalized radar cross section (NRCS) of the sea has been developed that is based on the scattering from a composite surface, i.e., one in which a slightly rough surface in the sense of Rice has been superimposed upon a large wave structure. The model predicts an upper bound (saturation value) of the NRCS with increasing wind speed and in addition yields expressions for the variation of the NRCS with frequency, polarization, and grazing angle. To verify the validity of the model in the higher sea states where spray, shadowing, and nonlinear wave interactions would be expected to influence the return, extensive measurements were made over the North Atlantic Ocean in February 1969. The instrumentation used in the program was the Naval Research Laboratory four‐frequency radar system which is an experimental radar installed in an EC‐121 (Super Constellation) aircraft. Nine flights were made, and data acquired in sea states with winds that varied from Beaufort Force 0 to 8 with a maximum sea state condition of a 24‐m/sec wind with 8.5‐meter significant wave height were observed. The results of the measurement have verified the existence of the upper bound for the NRCS that is asymptotically approached in windspeeds in excess of 5 m/sec. In addition, the data have confirmed the variation of the cross section with frequency, polarization, and grazing angle with the proviso that the ‘tilting’ of the scattering surface by the large wave structure be assumed in the region of shallow gra

ISSN:0148-0227    

DOI:10.1029/JC076i006p01525

年代:1971

数据来源: WILEY

摘要:

The stagnant film model for the transport of CO2across the air‐sea interface has been reexamined. By incorporating the constraint of electroneutrality, equations are derived that govern the flux of the carbon containing species within the film. Electroneutrality obviates the incorrect assumption of constantpH that is implicit in previous exchange calculations. Numerical results for typical ocean conditions indicate that for film thicknesses less than, say, 400μ. oceanic exchange is not influenced by the hydration/dehydration reactions of dissolved carbon dioxide. This conclusion is in substantial agreement with the approximate analysis ofBolin[1960]. However, if suitable catalysts are present in the ocean (there is recent evidence to suggest that this may be true [Berger and Libby, 1969]), the accelerated reactions are capable of augmenting the exchange rate by a considerable amount. The extent of this enhancement can be predicted by the model presented he

ISSN:0148-0227    

DOI:10.1029/JC076i006p01539

年代:1971

数据来源: WILEY

摘要:

A one‐dimensional thermodynamic model of sea ice is presented that includes the effects of snow cover, ice salinity, and internal heating due to penetration of solar radiation. Surface‐energy balances determine rates of ablation and accretion; diffusion equations govern heat transport within the ice and snow. The incoming radiative and turbulent fluxes, oceanic heat flux, ice salinity, snow accumulation, and surface albedo are specified as functions of time. Starting from an arbitrary initial condition, the model is integrated numerically until annual equilibrium patterns of temperature and thickness are achieved. The model is applied to the central Arctic. Input values for the initial test of the model are based on observational data. Values predicted by the model for the average ice thickness (288 cm), amount of surface ablation (40 cm), and the temperature field all agree closely with field observations. Other results from the model indicate that, under present conditions, the ocean must supply 1 to 2 kcal/cm2year to the ice; an additional 4 kcal/cm2year would cause the ice to vanish. Annual snow depths less than 70 cm are shown to have little effect on equilibrium thickness; snow depths greater than 70 cm would result in much thicker ice. Comparison of observed and calculated temperature profiles suggest that about 2.0 to 2.5 kcal/cm2year of the incoming short‐wave radiation penetrates the ice and contributes to internal heating. Average ice albedos under 0.50 would cause the ice to vanish in a few

ISSN:0148-0227    

DOI:10.1029/JC076i006p01550

年代:1971

数据来源: WILEY

摘要:

A steady progressive wave of maximum amplitude can be defined as a wave that has a corner flow at its crest. An analytical examination of the response of such a corner flow to certain perturbations gives a realistic description of the breaking of a spilling breaker. In particular it is shown that breaking will occur in the direction of propagation of the wave.

ISSN:0148-0227    

DOI:10.1029/JC076i006p01576

年代:1971

数据来源: WILEY

摘要:

A procedure for classifying lightning discharges into cloud‐to‐ground or cloud‐to‐cloud type is developed that is based on a set of measurements of the frequency content of both horizontally and vertically polarized sferic signals from lightning discharges. The data corresponding to 84 visually identified discharges from one storm were used to develop the procedure. Additional data corresponding to 50 identified discharges from another storm were used to test the resulting classification scheme. Up to 82% agreement was found on the test samples between visual identification of the discharge and the type given by the classification scheme. We found significant difference in the frequency content of the horizontally polarized sferic signal from cloud‐to‐ground and cloud‐to‐cloud discharges. Also, the polarization ratio of the signal in the 50‐kHz range was found to be considerably different for the two ty

ISSN:0148-0227    

DOI:10.1029/JC076i006p01582

年代:1971

数据来源: WILEY

摘要:

Daytime data from the high‐resolution infrared radiometer (0.7‐ to 1.3‐μm band) on Nimbus 3 have sufficient resolution and contrast to map the earth's major hydrologic features and plant distributions. Major drainage systems in humid regions and drainage basins in arid areas and bodies of open water are obvious in the imagery, in clear contrast with other surface features. Data from Africa, the Middle East, and North America contain solar reflectance variations that permit the identification of major plant associations, such as deciduous, coniferous and rain forests, savannahs, steppes, and desert scrub. Areas of desert sands have high reflectivity; volcanic outcrops are very dark; both are easily distinguished from the vegetative patterns. Seasonal variations in vegetative development and hydrologic changes can be extracted from th

ISSN:0148-0227    

DOI:10.1029/JC076i006p01588

年代:1971

数据来源: WILEY