摘要:

Observations of the temporal and spatial distribution of N2O in solution are not yet sufficient to permit quantitative assessment of the role of the ocean in the budget of atmospheric N2O. Consideration of the global nitrogen cycle suggests that the land should be the primary source of N2O. The gas is removed in the atmosphere by photolysis and by reaction with O(¹D), and there may be additional sinks in the ocean

ISSN:8755-1209    

DOI:10.1029/RG014i002p00143

年代:1976

数据来源: WILEY

摘要:

Chemical kinetic data for more than 250 gas phase reactions of possible importance in the atmosphere have been reviewed. The results of available evaluations of the rate data are tabulated with selected recent experimental values. A preferred value for each reaction rate constant is indicated. A brief discussion of some of the experimental techniques that have been utilized is also given. This discussion emphasizes the capabilities and limitations of the individual techniques. The tables should be of use to those interested in modeling the complex chemical processes of the stratosphere, troposphere, or the urban atmosphere.

ISSN:8755-1209    

DOI:10.1029/RG014i002p00151

年代:1976

数据来源: WILEY

摘要:

Experimental and theoretical values for precipitated electron and proton fluxes in the area of the South Atlantic geomagnetic anomaly are reviewed. Observations of airglow which have been reported in the literature suggest that there is no enhancement in the Brazilian region, though there may be some in the southeastern part of the Atlantic area. There is evidence from various types of observations that the electron density in the ionosphere is greater over the South Atlantic than at comparable places elsewhere, especially during magnetic disturbances, and similarly the ion density shows enhanced values. Electron and neutral temperatures may also be higher than normal in the anomalous region. Observations are required in all these fields, coordinated with particle flux measurements from rockets and satellites in the area, to confirm the reality of the effects and their relationship to particle precipitation.

ISSN:8755-1209    

DOI:10.1029/RG014i002p00173

年代:1976

数据来源: WILEY

摘要:

Diverse and independent measurements of the variation of particle convection boundaries with geomagnetic activity are used to obtain relations between the magnitude of a large scale electric field and theKpindex. The relations are compared with measured fields and with models and are found to be consistent with diverse observations and probably more reliable than results previously obtained.

ISSN:8755-1209    

DOI:10.1029/RG014i002p00189

年代:1976

数据来源: WILEY

摘要:

Several mathematical methods which are available for the description of magnetic fields in space are reviewed. Examples of the application of such methods are given, with particular emphasis on work related to the geomagnetic field, and their individual properties and associated problems are described. The methods are grouped in five main classes: (1) methods based on the current density j, (2) methods using the scalar magnetic potential γ, (3) toroidal and poloidal components of the field and spherical vector harmonics, (4) Euler potentials, and (5) local expansions of the field near a given reference point. Special attention is devoted to models of the magnetosphere, to the uniqueness of γ as derived from observed data, and to theLparamete

ISSN:8755-1209    

DOI:10.1029/RG014i002p00199

年代:1976

数据来源: WILEY

摘要:

The interaction between the atmosphere and the underlying surface occurs through the planetary boundary layer. The basic information required for describing the large‐scale processes in terms of the boundary layer processes relates to the turbulent fluxes of momentum, heat, and moisture, the height of the boundary layer, and surface parameters such as soil moisture content and topography.The numerical models of the atmospheric general circulation incorporate the (statistical) effects of the boundary layer processes in terms of the large‐scale parameters computed by the model through parameterization techniques. This paper reviews various parameterization techniques used in current general circulation models and suggests the need for a sensitivity test to find the best

ISSN:8755-1209    

DOI:10.1029/RG014i002p00215

年代:1976

数据来源: WILEY

摘要:

This is a study of the formulation, some basic solutions, and applications of the Biot linearized quasistatic elasticity theory of fluid‐infiltrated porous materials. Whereas most previously solved problems are based on idealizing the fluid and solid constituents as separately incompressible, full account is taken here of constituent compressibility. Previous studies are reviewed and the Biot constitutive equations relating strain and fluid mass content to stress and pore pressure are recast in terms of new material parameters, more directly open to physical interpretation as the Poisson ratio and induced pore pressure coefficient in undrained deformation. Different formulations of the coupled deformation/diffusion field equations and their analogues in coupled thermoelasticity are discussed, and a new formulation with stress and pore pressure as basic variables is presented that leads, for plane problems, to a convenient complex variable representation of solutions. The problems solved include those of the suddenly introduced edge dislocation and concentrated line force and of the suddenly pressurized cylindrical and spherical cavity. The dislocation solution is employed to represent that for quasi‐static motions along a shear fault, and a discussion is given, based on fracture mechanics models for fault propagation, of phenomena involving coupled behavior between the rupturing solid and its pore fluid, which could serve to stabilize a fault against rapid spreading. Also, the solution for a pressurized cylindrical cavity leads to a time‐dependent stress field near the cavity wall, and its relevance to time effects in the inception of hydraulic fractures from boreholes, or from drilled holes in laboratory specimens, is discussed. Various limiting cases are identified, and numerical values of the controlling porous media elastic parameters are given for several

ISSN:8755-1209    

DOI:10.1029/RG014i002p00227

年代:1976

数据来源: WILEY

摘要:

Numerical models of the large‐scale circulation of the oceans have developed into a useful tool for the interpretation of oceanographic data and the planning of new observational programs. Idealized numerical models with simplified geometry and physics have extended the analytic theory of the wind‐driven ocean circulation into the range in which inertial effects determine the solution. Recent numerical work has shown how stratification and baroclinic instability further modify a wind‐driven ocean circulation. Other results obtained by simplified numerical models include important predictions about the spectral properties of geostrophic turbulence in the ocean. Another class of numerical models has been developed which attempts to model the geometry and physics of the ocean circulation in a more detailed way, allowing a quantitative comparison with observations. Interesting results have been obtained for the Indian Ocean which simulate the seasonal variations of the Somali Current. Other Soviet and U.S. model studies using the observed density field as input show that pressure torques acting on bottom topography can be as large as the torques exerted by the wind acting at the surface. As yet, detailed simulations of the ocean circulation in a major ocean basin which include the effect of mesoscale eddies have not been under

ISSN:8755-1209    

DOI:10.1029/RG014i002p00243

年代:1976

数据来源: WILEY

摘要:

Lunar volcanic deposits are dominated by areally extensive mare units occurring in regionally low areas predominantly on the lunar near side. Data obtained from lunar orbit and earth‐based observations have been used to extend the detailed characterizations derived from Apollo and Luna sample return missions to other parts of the moon. Mare volcanism occurred over a period of about 1.3 billion years (b.y.), from about 3.8 to about 2.5 b.y. ago, although the absolute age of the youngest flows is not known. An early Ti‐rich mare phase (Apollo 11 and Apollo 17 type basalts) flooded large areas of the eastern portion of the lunar near side in the early Imbrian Period (about 3.5–3.8 b.y. ago). An intermediate age, less Ti‐rich phase (Apollo 12 and Apollo 15 type basalts) flooded widespread areas of the moon predominantly in the middle to late Imbrian Period (about 3.0–3.5 b.y. ago). Finally, a second Ti‐rich phase (unsampled by Apollo and Luna) flooded portions of Mare Imbrium and the western maria in the early Eratosthenian Period (about 2.5–3.0 b.y. ago). Features associated with mare deposits and processes include lobate scarps, sinuous rilles, domes, cones, dark halo craters, collapse craters, kipukas, lava terraces, mare ridges, and volcanic complexes. The very fluid nature of lunar lavas, their voluminous and extensive flows, and the dominance of volcanic landforms of nonexplosive origin all strongly indicate that lunar eruptions and deposits are most similar to terrestrial basaltic flood and Hawaiian eruptions. Volcanic morphologic features, deposit volumes, extrusion rates, and association of many sources with major crustal fractures all suggest that mare lavas originated at subcrustal depths and worked their way to the lunar surface through a passive but fractured lunar crust. Lavas preferentially infilled the existing low regions of the moon, apparently in a hydrostatic mode. Since lunar impact basins produce most of the topographic lows, mare deposits are concentrated in and around these features. The lunar crust acted essentially as a passive platform on which mare lavas were emplaced. Far side mare deposits are patchy but are concentrated on the floors of the largest basins. Thicker far side crust and hydrostatic emplacement of mare lavas may explain the lack of extensive far side deposits even in deep basins. Individual maria had a history of filling largely determined by the geometry and state of degradation of the basins in which they occur. Mare deposits are generally less than about 2 km in thickness but probably approach 6–8 km locally in the center of some mare basins. The process of filling took place over extensive periods of time and produced complex deposits. Although some near‐surface fractionation of mare lavas must have occurred, there is little photogeologic evidence for environments in which extensive fractionation would take place; lavas appear to have erupted at high rates, to have been very fluid, and to have spread out into thin flows; evidence is lacking for shallow magma reservoirs and for lava lakes on the scale of a mare basin. The portion of lunar mare deposits emplaced on the surface of the moon represents less than 1% of the total volume of the lunar crust. There is little unequivocal morphologic evidence for extensive highland volcanism, although intense bombardment may have erased such evidence from early lunar history. The majority of upland plains appear to be related to impact processes. Morphologic evidence for local highland volcanism is found primarily in the form of spectral

ISSN:8755-1209    

DOI:10.1029/RG014i002p00265

年代:1976

数据来源: WILEY