摘要:

This paper presents the first measurements of the vertical distribution of CFC‐22 in the stratosphere resulting from gas chromatography‐mass spectrometry (GC‐MS) of air samples collected cryogenically between 10 and 33 km altitude, at 44°N. Results from 2 balloon flights carried out on September 20, 1982, and on September 10, 1983, are shown and compared with a theoretical profile computed by means of a 1‐D model. Our results demonstrate that CFC‐22 mixing ratios decrease more slowly with height than many other halocarbons indicating that this hydrohalocarbon may become an important source of ClOxradicals in the upper st

ISSN:0094-8276    

DOI:10.1029/GL012i001p00001

年代:1985

数据来源: WILEY

摘要:

A number of lines belonging to the ν3fundamental vibration‐rotation band of hydrogen cyanide (HCN) have been identified in atmospheric infrared absorption spectra obtained on high‐altitude balloon flights at 32°N in 1976 and at 30°S in 1977. Quantitative analysis of these spectral features has resulted in the first determination of atmospheric HCN concentrations in the southern hemisphere, as well as an independent estimate of stratospheric HCN abundance in the northern hemisphere. Within the uncertainties of our own and previous measurements, our northern‐hemisphere result is consistent with those of other investigators, and southern‐hemisphere HCN concentrations appear to be similar to those in the northern

ISSN:0094-8276    

DOI:10.1029/GL012i001p00005

年代:1985

数据来源: WILEY

摘要:

Free tropospheric measurements of CS2were made over a latitude range 45°N to 45°S. The mean of 52 measurements was 5.7 pptv. The standard deviation and standard error of the mean were 1.9 and 0.3 pptv respectively. The amounts of CS2in the northern and southern hemispheres were statistically the sam

ISSN:0094-8276    

DOI:10.1029/GL012i001p00009

年代:1985

数据来源: WILEY

摘要:

A balloon sounding to 32 km altitude was conducted at the U. S. station on McMurdo Sound in Antarctica in October 1983. The purpose of the sounding was twofold. First, to determine the extent to which sulfuric acid aerosol from the April 1982 eruption of the Mexican volcano El Chichon had affected the Antarctic stratospheric aerosol layer and, second, to determine if sulfuric acid condensation nuclei are produced at high altitude in the Antarctic stratosphere as had been observed in the northern hemisphere during the late winter ‐ early spring period. The results indicate that stratospheric transport to the south polar region was very effective with aerosol mixing ratios observed to be similar to those in the northern hemisphere for the same time period. Observation of relatively high concentrations of condensation nuclei at high altitude and associated temperature variations tend to support the validity of an aerosol production process proposed to explain earlier northern hemisphere result

ISSN:0094-8276    

DOI:10.1029/GL012i001p00013

年代:1985

数据来源: WILEY

摘要:

Activities of222Rn and210Po were measured in a September, 1983, basic andesite lava from Arenal and a November, 1983, basalt from Kilauea, starting 3 and 1 days after eruption, respectively. In both cases, in‐growth patterns show that all Rn volatalized during eruption. Po degassing also was complete at Kilauea but only 84±10% at Aren

ISSN:0094-8276    

DOI:10.1029/GL012i001p00017

年代:1985

数据来源: WILEY

摘要:

Within the past five years all the groups of continuously flowing chloride springs in Whakarewarewa have had some interruption to, or cessation of, flow. This indicates that the geothermal field is in decline. An historical survey establishes that formerly the response time of the springs to minima in cumulative deviation of rainfall was about 8 years consistent with an analogue model of the field. The recent response time, less than one year, is consistent with the model only when the effects of exploitation are included, indicating that withdrawal from wells is causing a major decline in the field.

ISSN:0094-8276    

DOI:10.1029/GL012i001p00021

年代:1985

数据来源: WILEY

摘要:

We adjusted the three‐dimensional locations of the monuments in the USGS Hollister trilateration network to fit line length observations observed in 1977. We used a Bayesian approach, incorporating prior elevation estimates as data in our adjustment procedure. We found no significant discrepancies in the measured line lengths, but significant elevation adjustments (up to 1.85 m) were needed to fit the length dat

ISSN:0094-8276    

DOI:10.1029/GL012i001p00025

年代:1985

数据来源: WILEY

摘要:

A Haskell matrix solution to the equation of stress equilibrium is used to describe the crustal response to a screw dislocation source lying beneath a uniform elastic crust capped by a region of layered rigidity. The solution is used to illustrate the effect a stratified crustal rigidity has on the near surface in situ stress field. Without accounting for this effect, it is possible to overestimate the deep tectonic stress levels inferred from in situ vertical gradients measured in the uppermost crust.

ISSN:0094-8276    

DOI:10.1029/GL012i001p00029

年代:1985

数据来源: WILEY

摘要:

Observations of the earthquake source‐time function are enhanced if path, recording‐site, and instrument complexities can be removed from seismograms. Assuming that a small earthquake has a simple source, its seismogram can be treated as an empirical Green's function and deconvolved from the seismogram of a larger and/or more complex earthquake by spectral division. When the deconvolution is well posed, the quotient spectrum represents the apparent source‐time function of the larger event. This study shows that with high‐quality locally recorded earthquake data it is feasible to Fourier transform the quotient and obtain a useful result in the time domain. In practice, the deconvolution can be stabilized by one of several simple techniques.In this paper, the method is implemented and tested on high‐quality digital recordings of aftershocks of the Jan. 9, 1982 Miramichi (New Brunswick) earthquake. In particular, seismograms from a Jan. 17 aftershock (017 13:33 GMT, local mag.=3.5) exhibit path or site effects which complicate the determination of source parameters. After deconvolution, the apparent far‐field source of this event is a simple pulse in displacement with duration ≈ 0.07 second for

ISSN:0094-8276    

DOI:10.1029/GL012i001p00033

年代:1985

数据来源: WILEY

摘要:

In boreholes where formation shear wave velocity is lower than borehole fluid velocity neither refracted shear waves nor pseudo‐Rayleigh waves can propagate. When frequency response of the sonde does not extend to low frequencies (e.g. 2 kHz) Stoneley waves are not excited. In such cases refracted P and leaking PL modes become dominant phases on a full waveform acoustic log. The P wave velocity can be determined from the first arrivals. Then, using synthetic seismograms and a waveform matching technique, formation shear wave velocity and attenuation can be estimated. This method is demonstrated using data from DSDP Site 612 in the Baltimore Canyon Trough area of the Atlantic margi

ISSN:0094-8276    

DOI:10.1029/GL012i001p00037

年代:1985

数据来源: WILEY