An image intensified, all‐sky, 6300‐Å airglow imaging system operating on Ascension Island is early 1981 has been used to assemble a photographic data base of several hundred airglow depletion patterns. By mapping the airglow depletion features along geomagnetic field lines to the equatorial plane, the geometrical characteristics of plasma depleted regions may be described over the 400‐ to 1200‐km altitude region above the equator. Such an analysis revealed that single or linear depletions tilted toward the west with an average skewness of 0.6° longitude west/100‐km altitude, corresponding to a zenith angle tilt of ∼40° at a height of 800 km. The tilts increased with local time during the evening hours, showing that an effective velocity shear of ∼0.05 m/s/km is required to account for the observed evolution. In several cases, the depletion geometry showed a ‘wishbone’ or bifurcated pattern. Such features had a mean height of bifurcation of 740 km and tilt factors very similar to those found for linear depletions observed during the same local time periods.

Two phonological process-based treatment procedures were applied in an ongoing clinical program. Subjects were 4 children aged 3:1, 3:8, 4:1, and 5:1. Two subjects were assigned to a minimal pairs contrasting procedure, and 2 were assigned to a modified cycles procedure based on results of a detailed phonological analysis. All children demonstrated marked changes in their phonological systems as shown by the results of pretreatment and follow-up generalization probes. Correct production generalized to sounds affected by the treatment process that were not a focus of training. Correct production of untrained sounds lagged behind that of trained sounds for all subjects. Results support the hypothesis that articulation remediation is enhanced by treating phonological processes as well as the notion that the acquisition of phonology is a gradual process. Both treatment procedures used in this study were found to be effective and efficient, as evidenced by the elimination of up to three phonological processes within 2 1/2 months for each subject.

Clinically, results suggest targeting morphosyntax first, followed by phonology, if using a block intervention sequence for children with concomitant morphosyntactic and phonological impairments.

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Six preschoolers aged 3:6 to 4:8 (years:months), with moderate-to-severe disorders in both language and phonology, received intervention that differentially focused on language, phonology, or both domains, Phonological intervention involved elicited imitation techniques and minimal pair contrasting. Language intervention involved an indirect narrative approach with focused stimulation The combination approach involved features of both. All subjects had both language and phonology goals, but the emphasis for these differed in the different treatments. Regardless of the intervention approach, a modified "cycles" approach was incorporated for phonology goals. Extensive phonological and morphological generalization probes, spontaneous language sampling, and use of the proportional change index for mean length of utterance served as measures of progress. Subjects who received direct phonological intervention showed a moderate improvement in both phonology and language. Subjects who received language intervention demonstrated small improvement in language and negligible improvement in phonology Subjects who received the combined intervention approach showed marked improvement in both domains.