CONTRIBUTION TO SIGNAL BY ELEMENTS OF THIN VERTICAL CONDUCTING VEIN IN DIPOLAR EM SYSTEMS*

As an extension of the eddy current pattern computed by Koefoed and Kegge (1968) for a thin vertical infinitely-conducting half-plate in presence of oscillating magnetic dipoles, this paper computes the contribution to the (electro-) magnetic anomaly at the receiver by each element of the vein separately. Twelve contour diagrams for such elemental contributions are presented as samples. Two points of general interest stand out: (1) The contributions from different portions of the vein are not all of one sign; the contribution from one part may cancel that from another; and (2) The portion of the vein nearest to the transmitter-receiver system does not necessarily make the largest contribution to the total measured signal.     

INLINE AND BROADSIDE EM DIPOLE DIPOLE PROFILING OVER A THIN VERTICAL INFINITELY CONDUCTING VEIN *

Master diagrams for electromagnetic responses of nine dipole dipole systems are presented for various depths of a vertical infinitely conducting vein. The YY system gives the minimum anomaly for both the inline and broadside arrays. Among other inline systems, it is difficult to decide the clearcut superiority of one system over the other, whereas the XX system in broadside array gives maximum anomaly.     

Chlorine partitioning in the stratosphere based on in situ measurements

Balloon‐borne cryogenic air sampler experiments have been conducted from a tropical (Hyderabad, 17.5°N) and a midlatitude (GAP, southern France, 44°N) station since 1987 in the altitude range of about 8‐35 km. Air samples are analysed at the Max Planck Institute for Aeronomy (MPAE) and Physical Research Laboratory (PRL) using various gas chromatographic techniques to obtain the vertical distributions of several halogenated source gases and long‐lived dynamical tracers. These observations are used to determine the stratospheric partitioning of the chlorine species into their organic and inorganic forms for the altitude range of 20 to 35 km. Distributions of inorganic chlorine indicate increase in their abundances with altitude, latitude and time. Mixing ratio correlations of organic and inorganic chlorine with N₂O have been obtained which also suggest that the rate of increase in inorganic halogens component in the stratosphere is larger than the increase rate of total organic halogen. This supports previous assessments that halogen‐induced ozone depletion will continue to be observed for a few more years, despite the decrease of halocarbon loading into the stratosphere since 1994.     

ELECTROMAGNETIC RESPONSE PATTERN OF A CONDUCTING VEIN *

Dividing a vertical conducting vein into horizontal strips, response of each of them is obtained for various transmitter receiver orientations.