摘要:

At present there are few models for which the effect of time‐varying parameters such as seasonal and diurnal changes in the solar zenith angle have been studied in detail. In particular, the possible effects on the model‐estimated environmental impact of aerospace operations in the high atmosphere have not been reported in the literature. Using a one‐dimensional model, we have studied the sensitivity to the time dependent variations of these parameters and its effect on the model‐predicted perturbations. This sensitivity seems to limit the interpretability of steady state

ISSN:0148-0227    

DOI:10.1029/JC080i018p02637

年代:1975

数据来源: WILEY

摘要:

The spread and abatement of the aerosol injected into the stratosphere by the explosion of Katmai volcano in Alaska on June 6, 1912, have been investigated. The spread of the dust veil and twilight observations are discussed. Turbidity was determined from solar radiation data obtained mainly in central and northern Europe and the United States. In Europe, volcanic turbidity was quite large but highly variable during the summer of 1912 and became rather low in February 1913, when it was still high over the United States. Temporary presence of Katmai dust over Mexico City is very questionable, so that increased turbidity over Peru during 1913 may have had other causes. The turbidity disappeared rather suddenly in late 1914. Average residence time of the dust was nearly 1 year.

ISSN:0148-0227    

DOI:10.1029/JC080i018p02643

年代:1975

数据来源: WILEY

摘要:

Meridional profiles of turbidity at some periods after the explosion of Katmai volcano in June 1912 at 58°N are compared with debris burden from Chinese nuclear tests. Katmai turbidity was previously obtained from solar radiation data, and debris burden was calculated from published mixing ratio data. Turbidity and burden generally peak strongly in arctic latitudes. Only two tests show indications of a bulge at 30°–45°N which probably existed for Katmai dust in spring 1913. The residence time of Katmai dust was found to have been about 1 year, whereas fallout of nuclear debris seems not to have started before the winter following the tests. For September 1912 the total amount of Katmai aerosol is estimated to have been 13 million metric tons. Analogies to predicted meridional distribution of SST pollutants are being menti

ISSN:0148-0227    

DOI:10.1029/JC080i018p02649

年代:1975

数据来源: WILEY

摘要:

Broad band electric field data are presented which show stepped leader wave forms preceding records of distant lightning return strokes. The majority of leader pulses are characterized by a large initial peak with a small and slow opposite overshoot. Total pulse durations range from 15–40 μs several milliseconds before the return stroke to 2–10 μs immediately preceding the return stroke. Close to the ground the stepped leader pulses occur at regular 10‐ to 20‐μs intervals and are almost unipolar with rise times of about 1 MS and full widths at half maximum in the range from 1 to 3 μs. The ratio of the peak of the last leader pulse to the subsequent return stroke peak is typically 0.1, which suggests a peak step current near the ground of about 10% of the return stroke p

ISSN:0148-0227    

DOI:10.1029/JC080i018p02653

年代:1975

数据来源: WILEY

摘要:

Neglect of the angle dependence of rebound probabilities for cloud droplets colliding with hail pellets has led to an overestimate of the amounts of charge that can be separated with the Elster‐Geitel mechanism. Application of the wind tunnel results obtained by Aufdermaur and Johnson suggests that the actual amounts of charge transferred may be less than 20% that assumed by ignoring the angle dependence. Observations of the charges carried by hail and rain particles within the bases of thunderclouds support these lower estimates and raise questions about the adequacy of the precipitation processes in explanations of thundercloud electrificatio

ISSN:0148-0227    

DOI:10.1029/JC080i018p02658

年代:1975

数据来源: WILEY

摘要:

The response times of three different types of oceanographic platinum resistance temperature sensors were measured employing the conventional rotating water container procedure. At low sensor immersion velocities (<100 cm/s) the response was strongly dependent upon the details of the sensor insertion velocity for one sensor design. With carefully defined measurement procedures, reproducible values for the ‘time constant’ were obtained, but their application in data analysis must be treated with caut

ISSN:0148-0227    

DOI:10.1029/JC080i018p02663

年代:1975

数据来源: WILEY

摘要:

Multiwavelength infrared radiometers used for determining the heat flux through the ocean surface are generally calibrated by using a near‐ambient temperature reference radiation source. Typically these sources have spectral emissivities that are less than unity and wavelength dependent. Analysis of the error produced by using a reference source which only approximates an ideal blackbody indicates that significant errors in the heat flux determination can arise unless the emissive properties of the source are well‐known and accounted

ISSN:0148-0227    

DOI:10.1029/JC080i018p02667

年代:1975

数据来源: WILEY

摘要:

The modified two‐stream approximation (MTSA) of the radiative transfer equation is further developed and applied to the calculation of the downward scattered solar ultraviolet radiation reaching the ground. This MTSA solution is parameterized and fitted to the results obtained from a multistream scattering code. To facilitate practical application, parameters introduced into the MTSA formula allow for variations in the concentration of ozone, wavelength, and solar zenith angle. The effect of ground albedo on the UV flux is also discussed. This formula should be useful in a variety of applications related to the photobiologically important solar UV radiation reaching the groun

ISSN:0148-0227    

DOI:10.1029/JC080i018p02672

年代:1975

数据来源: WILEY

摘要:

The magnitudes of water surface temperature fluctuations induced by surface waves of known dynamic characteristics were measured. An infrared radiometer, capable of detecting temperature changes less than 10−4°C with response only in the 8‐ to 13‐μm spectral region, was the prime diagnostic tool. The major experimental task was to discriminate between the thermal and reflectance contributions to the wave‐induced total radiometric signal. A technique which measures the upper bound of the reflectance contribution was developed, validated, and implemented. The magnitude of the measured temperature fluctuations induced by small amplitude monochromatic surface waves of near‐ideal characteristics agreed well with predictions from linear theories. In the linear wave dynamic regime the amplitude of the wave‐induced temperature fluctuation is dependent upon the near‐surface heat transfer. This dependence was found to be linear by systematically increasing the surface heat transfer by means of an increase i

ISSN:0148-0227    

DOI:10.1029/JC080i018p02677

年代:1975

数据来源: WILEY

摘要:

A theoretical expression for the joint distribution of wave period and amplitude, which was previously derived for a Gaussian record with a narrow spectrum, is restated in simple form. According to this distribution the variability of wave periods, for waves of a given height, is inversely proportional to the wave height, so that the higher waves tend to be more regular. The distribution is found to agree well with some observations of wave periods and amplitudes from the Gulf of Mexico, as given by Bretschneider (1959).

ISSN:0148-0227    

DOI:10.1029/JC080i018p02688

年代:1975

数据来源: WILEY