摘要:

Model sensitivity experiments were conducted by using correlated ensemble variations of reaction rate coefficients. For all the simulation experiments tested, the theoretically derived concentration profiles of trace species were in comparable agreement with stratospheric observations. Thus current stratospheric measurements seem to be inadequate to assist in reducing the current uncertainties in kinetic rate data. Given this current range of uncertainties in rate coefficients, it is found that by varying as few as three rate coefficients within the estimated (Hampson and Garvin, 1975) uncertainty range the effect on ozone of lower stratospheric injection of NOxcan be reversed. Consequently, it is clear that as a first step toward further progress more precise laboratory measurements of certain reaction rate coefficients are needed.

ISSN:0148-0227    

DOI:10.1029/JC082i006p00935

年代:1977

数据来源: WILEY

摘要:

A theory on the production of ozone, nitrous oxide, nitric oxide, and nitrogen dioxide during a thunderstorm is presented. The catalytic agents for the production of the molecules are lightning and point discharges. The concept of an efficiency parameter giving the number of molecules produced per unit of energy absorbed by the atmospheric constituents from lightning or point discharges is central to the theory. Values of the efficiency parameters are given for two cases. In one case the parameters are for atomic oxygen and nitrogen recombining with the atmospheric constituents. In the other case the parameters are for an equal number of neutral and ionized atomic species of oxygen and nitrogen recombining with the atmospheric constituents. Parameters for the two cases, which should span the actual physical situation, are given because the degree of ionization of the recombining atoms is unknown. Parameters relevant to laboratory discharges and lightning are given. An assessment of the importance of thunderstorms as a worldwide source of ozone, nitric oxide, and nitrogen dioxide would require a much better understanding of the sinks and transport processes; however, thunderstorms are likely to be important as a large interim source of ozone and oxides of nitrogen for areas near and in thunderstorms. If certain suggested reactions for the production of nitrous oxide are verified, thunderstorms could be an important worldwide source of nitrous oxide.

ISSN:0148-0227    

DOI:10.1029/JC082i006p00943

年代:1977

数据来源: WILEY

摘要:

The electric fields produced by stepped and dart‐stepped leaders which immediately precede return strokes in lightning discharges to ground have been recorded in Florida and Arizona. The mean interval time between normal steps is about 16 μs, and the mean interval between dart steps is 6–8 μs. The amplitudes of leader pulses in Florida increase just prior to the return stroke, the largest usually being about 10% of the return stroke peak. In Arizona the leader pulse amplitudes are smaller than those in Florida, in relation to the return stroke, and are not as easy to identify. The shapes of the fields produced by normal steps are similar to dart steps, and the dart steps are very similar to regular sequences of pulses produced by many intracloud discharges. The 10–90% rise times of individual step wave forms are often less than 0.3 μs, and the full width at half maximum of a step pulse is typically 0.4–0.5 μs under conditions where the propagation distortion is minimal. The amplitudes and the shapes of leader step wave forms suggest that the peak step current is at least 2000–8000 A close to the ground and that the maximum rate of change of step current is 6–24 kA/μs or larger. A rough estimate of the minimum charge lowered during the formation of a step

ISSN:0148-0227    

DOI:10.1029/JC082i006p00951

年代:1977

数据来源: WILEY

摘要:

We calculated the temperatures of ice spheres in the mesosphere by establishing an equation for the balance among the power absorbed by the particle from the solar and terrestrial radiation fields, the power emitted by the particle as thermal radiation, and the power transferred from the particle to the atmosphere by collisions with air molecules. In some cases the particle temperature that ensues can result in a saturation vapor pressure at the ice surface that exceeds the pressure of the ambient atmosphere, and the particle can therefore not continue to exist. Equilibrium particle temperatures have been analyzed to study atmospheric exclusion limits for ice spheres in the mesosphere as a function of particle radius and altitude.

ISSN:0148-0227    

DOI:10.1029/JC082i006p00961

年代:1977

数据来源: WILEY

摘要:

A simple method is developed to obtain the relative atmospheric aerosol content over low‐albedo surfaces (water) from observations of the Erts (now Landsat) type. The method is based upon a derived relationship between the aerosol optical thickness and the satellite‐observed upward scattered solar radiation and upon the proportionality of aerosol optical thickness to aerosol column density. The method is successfully applied to Erts 1 observations of the Middle East by comparing the aerosol content on a day when the meteorological observations indicated high atmospheric dust content with that on a day on which normal meteorological conditions prevai

ISSN:0148-0227    

DOI:10.1029/JC082i006p00967

年代:1977

数据来源: WILEY

摘要:

Excess acoustic attenuations in the frequency range 5–160 kHz have been used to deduce densities of bubbles of radius of 15–300 μ at depths of 3–36 m in water up to 1 km deep. The measurements were made over an acoustic path 1–5 m long. Correlations have shown dependence on season, sundown and sunrise, wind, and presence or absence of sea slicks and windrows. These inferred microbubbles are evidently of biological as well as physica

ISSN:0148-0227    

DOI:10.1029/JC082i006p00971

年代:1977

数据来源: WILEY

摘要:

Transports for Lake Superior were obtained by using a depth‐integrated model applied to a 6×6 km grid. The results were used to explain the movement of red clay plumes in extreme western Lake Superior. For northeasterly winds the calculated transports and Landsat data on turbidity show that the plumes originating along the Wisconsin shore move toward Minnesota Point and are then taken out along the axis of the arm of the lake because of a return path produced by currents along the Minnesota and Wisconsin shores converging at Minnesota Point. The results from the model also account for the migration of taconite tailings along the Minnesota shore from Silver Bay to the Duluth water inta

ISSN:0148-0227    

DOI:10.1029/JC082i006p00977

年代:1977

数据来源: WILEY

摘要:

Large‐scale (100 km) rectilinear lead patterns are a common feature of the Arctic Ocean ice cover. We show that many of the characteristics of these patterns can be explained by analogy with rock mechanics. In particular, the existence of two intersecting lead sets, the typical intersection angles of 28°, and the observed relative shearing motions are consistent with faulting associated with semibrittle failure. Further support for this explanation has been obtained by using NOAA and Landsat satellite imagery over an approximately 100‐km‐square area of the Beaufort Sea. These provide coverage of 2 days of ice deformation prior to the formation of a lead at 14° to the axis of compression. Strains of 4% over the 2‐day period are within the range attributed to rock distortion preceding semibrittle failure. Finally, we suggest that the range from brittle to plastic type behavior is feasible within the Arctic Ocean sea ice, depending upon the applied rate of strain and/or the ambient confining

ISSN:0148-0227    

DOI:10.1029/JC082i006p00979

年代:1977

数据来源: WILEY

摘要:

The vertical distributions of Na and Cl in the marine atmosphere near the Bahamas were measured on five consecutive days. The aerosols were sampled isokinetically from an aircraft at 8 or 10 different altitudes between 75 and 2000 m. The weights of Na and Cl in each sample were determined by neutron activation analysis. Since the Cl/Na ratio in the aerosols was close to that in seawater, it was concluded that these elements were present as sea salt. The concentrations of Na + Cl ranged from 4–7 μg/m3at 75 m to about 0.5 μg/m3at 200

ISSN:0148-0227    

DOI:10.1029/JC082i006p00988

年代:1977

数据来源: WILEY

摘要:

A portable Gardner counter on board the R/VAlpha Helixwas used to obtain Aitken nuclei data over the Pacific Ocean from San Diego, California, to San Martin, Peru, during a 2‐week period in March 1976. The number concentration distribution reflects the passage through several distinct synoptic scale circulation patterns. The highest nuclei (N) concentrations, over 4000 N/cm3, were measured during a short period of time in the northeast trade wind belt off Central America, while the lowest values, near 250 N/cm3, occurred in the southeast trade wind circulation off the Peruvian coas

ISSN:0148-0227    

DOI:10.1029/JC082i006p00991

年代:1977

数据来源: WILEY