摘要:

A useful measure of the importance of a given parameter in an inverse problem is the standardized partial derivative, which is scaled by thea prioriuncertainty of the parameter in question. Because the density distribution in the upper mantle is poorly known, thea prioriuncertainty for density is rather large; thus density must generally be considered as a variable in the inversion of surface wave phase velocity data.

ISSN:0094-8276    

DOI:10.1029/GL003i011p00637

年代:1976

数据来源: WILEY

摘要:

We have examined a large number of standard marine refraction stations to determine the general relation of crustal and mantle velocity to spreading direction and age in the Pacific. Crustal anisotropy is insignificant, as is variation of lower crustal velocity with age. Mantle velocities exhibit a high correlation with both age and azimuth indicating an increase of velocity with age and about 5% anisotropy with highest velocity in the direction perpendicular to the local magnetic anomalies.

ISSN:0094-8276    

DOI:10.1029/GL003i011p00639

年代:1976

数据来源: WILEY

摘要:

Clear evidence for the existence of a quasi‐biennial geomagnetic variation is shown by an analysis of annual averages of the horizontal (H) component of the geomagnetic field observed at five observatories. The analysis uses a numerical filter, which is equivalent to taking the second order time derivative of the time series. The cause for the variation is external to the earth because its amplitude depends on magnetic activity. The second order time derivative of H is well correlated with the corresponding time derivatives of the relative sunspot number and 10.7 cm solar flux. It is suggested that quasi‐biennial oscillations observed in the geomagnetic field, cosmic rays, stratospheric zonal wind and temperature, total ozone, and other meteorological parameters could be produced by a common cause on the

ISSN:0094-8276    

DOI:10.1029/GL003i011p00643

年代:1976

数据来源: WILEY

摘要:

A synthetic aperture imaging radar flown on the NASA CV‐990 aircraft has yielded pictures of ocean surface features interpreted as being due to short wavelength internal waves. Wave packets similar to those detected from the Landsat‐1 satellite and other platforms have been observed off the coast of Alaska under conditions suitable for tidal excitation of internal waves. Both the radar and the Landsat images show variations in reflectivity across each wave in a packet that range from low to high to normal. The variations are evidence for the simultaneous existence of two mechanisms proposed to explain surface signatures of internal waves; roughening due to wave‐current interactions and smoothing due to slick formation. The rough region leads the smooth one in phase by one‐fourth to one‐half a w

ISSN:0094-8276    

DOI:10.1029/GL003i011p00647

年代:1976

数据来源: WILEY

摘要:

Submicron flyash particles show a preferential surface concentration of sulfur and chlorine in comparison to their matrix elements, e.g., aluminum and silicon. The relationship between concentration of surface deposited matter and inverse particle diameter suggests that S and Cl are adsorbed and oxidized on flyash particles after volatilization in the high‐temperature zone of the boiler. This leads to the formation of cloud nuclei even before a sulfur gas‐to‐particle conversion takes

ISSN:0094-8276    

DOI:10.1029/GL003i011p00651

年代:1976

数据来源: WILEY

摘要:

A satellite‐borne energetic ion mass spectrometer experiment has detected fluxes of O+and H+ions flowing up out of the ionosphere in the auroral and polar regions. The observed ions have energies in the keV range, narrow pitch‐angle distributions aligned along the magnetic field direction and peak flux intensities of the order of 108(cm²‐sec‐sterad‐keV)−1. The observations were made at altitudes between 5000 and 8000 km on both the day and nightsides

ISSN:0094-8276    

DOI:10.1029/GL003i011p00654

年代:1976

数据来源: WILEY

摘要:

Atmospheric ice nuclei were measured upwind and within the effluent plume of a coal‐fired powerplant during February 1976. Aerosol particles were captured on two types of membrane filters (Nuclepore and Millipore) and processed in two different thermal diffusion chambers, one calibrated to produce a 100% saturation relative to water and the other to produce a slight supersaturation relative to water. Consequently, the ice nuclei measured were active in the modes that are dominant in diffusion chambers, viz., deposition nucleation and condensation‐followed‐by‐freezing nucleation. Results indicate that plume particles do not act as ice nuclei between the temperatures of −10 and −20°C, nor do combustion gases in the plume deactivate natura

ISSN:0094-8276    

DOI:10.1029/GL003i011p00657

年代:1976

数据来源: WILEY

摘要:

A significant natural sink for halocarbons may exist in ion‐molecule reactions in the troposphere. Laboratory measurements, under conditions approximating the real atmosphere in all respects except ion age, show large rate constants for removal of CCl4 and CFCl3, apparently by atmospheric ions. The rate constant for CF2Cl2 is much smaller. If the same rate constants hold for older ions, the lifetimes against removal by this mechanism in the atmosphere are about 41 yr for CCl4 and 70 yr for CFCl3. Under steady state conditions a sink of this magnitude may decrease the global concentration of CFCl3 by a factor tw

ISSN:0094-8276    

DOI:10.1029/GL003i011p00661

年代:1976

数据来源: WILEY

摘要:

The open source neutral mass spectrometer (OSS) on the Atmosphere Explorer‐C satellite has measured neon in the thermosphere. The absolute density of Ne is close to that predicted by using the ground level fraction by volume of Ne along with the assumption of diffusive equilibrium above 100 km. Data is presented for both geomagnetically quiet and disturbed circular orbits. At 290 km, a typical low latitude value of [Ne] is 3.0 × 104cm‐3. At this altitude Ne appears to be predominantly controlled by temperature except during magnetic disturbances, when offsetting forces due to wind systems may be pre

ISSN:0094-8276    

DOI:10.1029/GL003i011p00665

年代:1976

数据来源: WILEY

摘要:

Seasonal wind variations over Antarctica in an altitude region from surface up to about 80 km are studied using data from 52 successful M‐100 meteorological rocket soundings at Molodezhnaya, Antarctica where the author worked during 1971‐73. It is found that the South Polar summer was characterised by light easterly winds increasing in strength with altitude and the winter exhibited strong westerly winds halving jet speeds of about 90 m/s increasing in strength as the season progressed, while the autumn and the spring were the wind reversal periods. The Antarctic winter regime was the most active period with a wind persistence of about 95% marked by strong westerly flow. Departures of the actual zonal winds from the Groves Model were found to be quite significant showing hemispheric asymmerties in the Northern and the Southern Hemispheres. The physical properties of the immense southern oceans play an important role in these differen

ISSN:0094-8276    

DOI:10.1029/GL003i011p00669

年代:1976

数据来源: WILEY