摘要:

Recent measurements of tropospheric mixing ratios of methane, non‐methane hydrocarbons (NMHC), and carbon monoxide (CO) from the Kenyan savannah are reported. NMHC mixing ratios are among the lowest reported for the continental boundary layer. CO mixing ratios are higher than marine measurements at these latitudes. Biomass burning may contribute significantly to mixing ratios of CO and NMHC's. Calculations based on the reactivity of the OH radical with NMHC's and CO indicate that NMHC's often initially consume more OH than C

ISSN:0094-8276    

DOI:10.1029/GL012i003p00113

年代:1985

数据来源: WILEY

摘要:

The possibility of a link between HCN and CH3CN in the atmosphere has been suggested recently. A new chemical analysis of this problem as well as model calculations indicate that, most probably, these gases are produced at the Earth's surface and destroyed by oxidation in the middle atmosphere. The strength of the photodestruction of these 2 molecules seems to be weak. It is unlikely that HCN is an atmospheric source of CH3CN.

ISSN:0094-8276    

DOI:10.1029/GL012i003p00117

年代:1985

数据来源: WILEY

摘要:

Cloud droplets are separated from atmospheric trace gases, rain drops and submicrometer aerosol particles on the basis of their aerodynamic properties and evaporated by dry air. The evolved trace gases and residual particles can be analyzed by in‐situ methods and collected for subsequent chemical analysi

ISSN:0094-8276    

DOI:10.1029/GL012i003p00121

年代:1985

数据来源: WILEY

摘要:

Sea level records are used to describe and discuss the response of the sea surface topography of the equatorial Pacific Ocean during the 1982‐83 El Nino event. During the second half of 1982 westerly winds over the western Pacific caused a draining of warm water from the area north of the equator and a first peak of sea level at the Galapagos Islands in December. During the first half of 1983 westerly winds to the south of the equator caused draining of warm water from the area between the Solomon Islands and the Marquesas Islands and a second peak of sea level at the Galapagos Islands in May. At the end of El Nino in October 1983 sea level over the entire equatorial Pacific was below normal, indicating a loss of warm water from the equatorial Pacifi

ISSN:0094-8276    

DOI:10.1029/GL012i003p00125

年代:1985

数据来源: WILEY

摘要:

Saturated ULF waves in the foreshock, with amplitudes comparable to the magnitude of the average field, are convected by the solar wind to the quasi‐parallel shock where the average field‐normal angle is less than, or about, 45°. Several examples from ISEE 1 and 2 magnetometer data show waves that defined local, instantaneous field‐normal angles very different periodically from the average. Local geometric conditions at the nominally quasi‐parallel shock varied from nearly parallel to nearly perpendicular, at the periods of typical upstream waves. Clear magnetic shock transitions occurred under temporarily quasi‐perpendicula

ISSN:0094-8276    

DOI:10.1029/GL012i003p00129

年代:1985

数据来源: WILEY

摘要:

Samples for paleomagnetic study were collected from the area of Red Sandstone Creek (Lat. 39.73°N, Long. 253.6) near Vail, Colorado, in hopes of locating the stratigraphic base of the Kiaman Reversed Interval to within a few meters. Previous workers had sampled the same upper Pennsylvanian and Permian Minturn and Maroon Formations in this section and had placed the base of the Kiaman at 91m to 213m above the Minturn Formation. The interval from 276m below to 420m above the Maroon/Minturn contact was sampled in the present study at one meter intervals where possible. Of the 171 samples collected, only 2 had near normal components. The 2 were not consecutive and the normal components were removed easily by thermal cleaning or were shown to be a viscous overprint of the present field. The previous workers were apparently misled by a lack of magnetic cleaning of their samples. The conclusion of this study is that the base of the Kiaman must be stratigraphically lower in this section. The pole position from the sampled section is Lat. 42.6°N, Long. 115.4°E, A95=2.75 for N=145 sampl

ISSN:0094-8276    

DOI:10.1029/GL012i003p00133

年代:1985

数据来源: WILEY

摘要:

Seismograms recorded along a 0.5 km‐deep borehole in Oroville, CA., show that ground‐level s‐wave velocity spectra at this location are a product of site effects. In the 6.25 to 50 hz range studied, both the Cleveland Hill fault, through which the borehole was drilled, and the rock above it contribute to a substantial loss of s‐wave energy. In first‐order approximation, the average apparent s‐wave quality factor, Qsa, along the well is 9. Across the fault zone the Qsadrops to a low of 3. Downhole, the seismograms can readily be separated into longitudinal and transverse components. Particle motion diagrams show that the s‐arrival is made up of two differently polarized waves. This splitting is possibly an effect of wave propagation in the highly cracked and probably anisotropic rock

ISSN:0094-8276    

DOI:10.1029/GL012i003p00137

年代:1985

数据来源: WILEY

摘要:

Study of 3242 full first order synthetic seismograms of isolated normal mode multiplets shows that constructive and destructive interference of the singlets comprising a multiplet can account for the noise‐corrected variance of free oscillation attenuation measurements in the frequency band 3.0‐4.0 mHz. This interference gives rise to a distribution of synthetic Q measurements which is sensitive to the short wavelength velocity features of a model. While individual attenuation measurements depend also on the moment tensor, the overall variance of Q fluctuations is insensitive to the characteristics of the source employed and depends little on the length of the time series processed. The Woodhouse‐Dziewonski model M84A of upper mantle velocity structure causes a scatter in the synthetics large enough to interfere significantly with any signal from lateral Q structure. Correlation of individual synthetics with data is poor, however, which suggests that either there are remaining uncertainties in the velocity model, that mode‐mode coupling occurs in the data in a way that is poorly understood, or that lateral attenuative structure contributes to the observed scatter. Resolution of any such Q structure will be difficult given the present d

ISSN:0094-8276    

DOI:10.1029/GL012i003p00141

年代:1985

数据来源: WILEY

摘要:

Wave propagation problems with radiation boundary conditions are non‐hermitian and therefore typically cannot be solved by expanding in terms of eigenfunctions that correspond to real eigenvalues. We present a method for solving such problems entirely in terms of a superposition of normal modes, using the "shifted eigenvalue" method outlined by Lanczos. In effect, the desired system with an outgoing radiation boundary condition is coupled to a system which is identical, but has an incoming radiation boundary condition. The combined system is hermitian, and thus has real eigenvalues. We present numerical computations for a one‐dimensional, semi‐infinite, homogeneous cont

ISSN:0094-8276    

DOI:10.1029/GL012i003p00145

年代:1985

数据来源: WILEY

摘要:

It is reaffirmed in this reply that the "classical" polar wind is based on the thermal escape of the light ions H+and He+. It is asserted that the polar ion flow observations presented in the Gurgiolo and Burch [1985] comment paper, made by the High Altitude Plasma Instrument (HAPI) instrument on Dynamics Explorer‐1 (DE), are O+and that the probable origin of these ions, which is consistent with the observations, is a highly localized region in the dayside polar cleft ‐ a distinctly different source region than that of the polar wind. Velocity and mass selection, as a result of E × B convection acting on ions from a localized source region in the polar cusp or the dayside polar cap boundary, determines the measured HAPI ion distribution. The Retarding Ion Mass Spectrometer (RIMS) instrument on DE, during the same time period, was measuring the light ion polar wind with flow energies of less than 2.5 eV which originated in the polar cap ionosphere very near the north magnetic

ISSN:0094-8276    

DOI:10.1029/GL012i003p00149

年代:1985

数据来源: WILEY