摘要:

Four heterogeneous reactions have been added to a one‐dimensional dynamic‐chemical model of the stratosphere. The heterogeneous reactions considered were the decomposition of ozone, the recombination of atomic oxygen, the reaction of nitrogen pentoxide with the liquid water dissolved in sulfuric acid particles, and the oxidation of sulfur dioxide by hydrogen peroxide sorbed by the particles. The calculations demonstrate the possibility that each of these reactions with the probable exception of heterogeneous atomic oxygen recombination plays an important role in stratospheric chemistry. The results emphasize the need for experimental determinations at stratospheric temperatures of the fraction of collisions between reactive atoms or molecules and impure sulfuric acid particles that result in chemical reacti

ISSN:0148-0227    

DOI:10.1029/JC080i024p03381

年代:1975

数据来源: WILEY

摘要:

A one‐dimensional cloud model is used to show how the coverage of droplets by surfactant films can suddenly change the growth of certain sizes of drops in a cloud drop spectrum. The retarded or accelerated growth depends upon the nature and thickness of the surfactant film, the size of the nuclei, and the cooling rate of the air parcel. Some conclusions are made concerning the practical application of interfering with the colloidal stability of warm clouds or fog

ISSN:0148-0227    

DOI:10.1029/JC080i024p03386

年代:1975

数据来源: WILEY

摘要:

The research described in this paper has emerged from a program designed to develop techniques for detecting and measuring atmospheric dispersion of effluent materials. Several diffusion experiments have recently been completed using sulfur hexafluoride (SF6) to trace gases, especially those emitted from tall stacks. Airborne and ground level concentration measurements using specially designed gas chromatographs were made. The results extracted from the experiments illustrate the usefulness of this method in detecting low‐level concentrations many kilometers downwind from given source

ISSN:0148-0227    

DOI:10.1029/JC080i024p03393

年代:1975

数据来源: WILEY

摘要:

A one‐dimensional diffusion model was combined with literature values for the rates of gas phase SO2oxidation reactions to calculate the stratospheric SO4−−profile. The results showed that the reactions of such trace species as OH and HOO with SO2are sufficiently fast to produce a sulfate layer above the tropopause similar to the observed Junge layer; the sensitivity of the model to the selection of boundary conditions and eddy diffusion profiles was also investi

ISSN:0148-0227    

DOI:10.1029/JC080i024p03399

年代:1975

数据来源: WILEY

摘要:

From video tape recordings of lightning flashes to ground in convective daytime storms at the NASA Kennedy Space Center, Florida, and near Ocala, Florida, statistical data are presented for the flash time duration, the number of strokes per flash, the time between all strokes, and the time between strokes having spatially separate channels. A daytime video tape ‘photograph’ of a stepped leader is reproduced. Finally, statistical data are presented for 13 long horizontal lightning discharges occurring along a line of nocturnal thunderstorms near Gainesville, Florida. These discharges all propagated horizontally near the freezing level (4.5 km) at an apparent average velocity between 5.6×103and 1.1×104m/s for a typical distance of 2–3 km. Eleven of the 13 horizontal discharges were preceded by or occurred within 16.7 ms of a glow in the cloud roughly 0.5 km above the horizontal

ISSN:0148-0227    

DOI:10.1029/JC080i024p03402

年代:1975

数据来源: WILEY

摘要:

This research provides a study of the horizontal variability of integrated boundary layer winds (IBLW's) for distances of the order of miles (kilometers). This information should be helpful for both theoretical and practical applications, e.g., boundary layer parameterization and air pollution models. The study concerned itself with winds integrated to a height of 1000 ft (300 m) and made use of data from two programs in which simultaneous and horizontally separated pilot balloon wind soundings were taken, Metromex 1971 and 1972 and a 1971 NOAA program in the Oklahoma City area. Only the data from rural locations were used in this study.Pibals were released simultaneously at locations ranging in number from 4 to 8 separated by distances varying from near 5 to near 30 mi (8 to 48 km). For a given release time, IBLW wind speed and direction differences between stations were determined for all station combinations. These differences were then used to compute rms speed and direction differences as a function of station separation rounded to the nearest 5, 10, 15, 20, 25, and 30 mi (8, 16, 24, 32, 40, and 48 km).The study shows that daytime rms speed differences are relatively independent of distance. At night, IBLW speed variability increases with increasing distance.

ISSN:0148-0227    

DOI:10.1029/JC080i024p03407

年代:1975

数据来源: WILEY

摘要:

A numerical model was constructed to simulate the scavenging of hygroscopic aerosols with the aim of studying the influence of several meteorological parameters on the composition of rainwater and the atmospheric aerosol content. The scavenging mechanism is found to be highly dependent on (1) the relative humidityRH, especially in relation to its effect on the size distribution of hygroscopic particles (for non‐hygroscopic particles the concentration effect during scavenging for low relative humidity is not so pronounced because the scavenging coefficients decrease as the impurities in the raindrops are being concentrated due to evaporation; e.g., for a rainfall intensity of 1.2 mm/h, 0.5‐mm rainfall, and non‐hygroscopic particles, the average rainwater concentration forRH= 50% is only 1.2 times larger than that forRH= 94%), (2) the rainfall intensity (or more fundamentally the raindrop size spectra), especially for small rainfalls, and (3) the chemical nature of the particles. With the assumption of no particle replenishment, only 20% of the initial aerosol mass remained in the subcloud layer after 4‐mm rainfall for the best scavenging conditions and after 15‐mm rainfall for the worst conditions. Therefore after these rainfalls, changes in the rainfall intensity and relative humidity would have little effect on the average rainwater concentration, since little aerosol mass remains to be scavenged. The model predictions of average rainwater concentration variations due to meteorological parameter changes are consistent with values actually

ISSN:0148-0227    

DOI:10.1029/JC080i024p03410

年代:1975

数据来源: WILEY

摘要:

Infrared (IR) in situ radiance observations, 8.0–14.0 μm (714–1250 cm−1) and 9.5–11.5 μm (870–1052 cm−1), of the West African Harmattan haze during the 1974 Global Atmospheric Research Project Atlantic Tropical Experiment field phase made possible the determination of some of the radiative properties of this tropospheric phenomenon. This in turn permitted development of a simple calculation model for radiative transfer through the haze. Radiometric observations of the dust haze, reaching from 600 m to 6.25 km, were analyzed for haze IR transmission. A transfer model incorporating these transmission properties gave an average calculated IR cooling rate of 0.09°C h−1for the entire haze layer compared to a haze‐free cloudless troposphere cooling rate of 0.06°C h−1for the same levels. The haze volume absorption coefficient was approximately 0.042 km−1for layers of all depths. This uniformity of the haze transmission was further evident in the direct correlation of its transmi

ISSN:0148-0227    

DOI:10.1029/JC080i024p03419

年代:1975

数据来源: WILEY

摘要:

Modified Ekman spirals developed beneath the ice in an upper layer extending to a depth of 15–25 m during the Arctic Ice Dynamics Joint Experiment pilot experiment under storm conditions with rapid ice drift. A momentum integral method has been used to evaluate ice‐water stress from profiles of current velocity. Maximum hourly mean stress was 1.66 dyn/cm2. The balance of forces on the ice for cases when wind speed exceeded 5 m/s showed a consistent pattern. Ice‐water stress, air‐water stress, and Coriolis force were all of the same magnitude. The pressure gradient force was, however, much smaller than these. Internal ice resistance, found as a residual from the force diagram, was directed about 135° to the left of the i

ISSN:0148-0227    

DOI:10.1029/JC080i024p03425

年代:1975

数据来源: WILEY

摘要:

The discrete‐ordinate method for radiative transfer is applied to an inhomogeneous atmosphere containing molecules and aerosols. The unknown coefficients in the analytic solution to the transfer equation are determined from boundary conditions of the diffuse intensity at the top and bottom of the atmosphere and from continuity conditions of radiation at the interface of the predivided homogeneous layers. The assumption of the homogeneity of the atmosphere is shown to overestimate the reflection (local albedo) and to underestimate the diffuse transmission at the bottom of the atmosphere. On the basis of calculations for the transfer of solar radiation in inhomogeneous hazy atmospheres we also show that the increase or decrease of the local albedo, due to the additional load of aerosols in the atmospheric boundary layer, depends on the characteristics of the surface albed

ISSN:0148-0227    

DOI:10.1029/JC080i024p03434

年代:1975

数据来源: WILEY