ALBERT

Notes: Summary Cephalotes atratus, the “giant turtle ant” of the Neotropical tribe Cephalotini, exhibits an intermediate stage in the evolution of polymorphism. The allometric growth line is straight, but the distribution of worker sizes is bimodal. An ethogram of workers in laboratory nests showed pronounced differences in behavior according to age. Under natural conditions, individual foraging specializations based on worker size were also found. Compared to other advanced cephalotines, this species appears to be less strongly adapted for arboreal life. A model is presented for the evolution of polymorphism in ants.

Notes: Summary In females ofPolistes gallicus the activity of corpora allata (CA) was determined volumetrically as well as radiochemically using the in vitro assay for juvenile hormone (JH). The results we have compared with the ovarian activity. During the period of egg maturation after overwintering the volume of CA is well correlated with the synthetic activity. But in overwintering females and in ovariectomized females we have observed very large glands which produced only little amounts of JH like the small glands of parasitized wasps. In all dominant females the CA we have found to be larger and more active than in subordinated females indicating that changes in the endocrine activity may be a primary result of social hierarchy.

Notes: Summary The colony-moving ofMyrmica rubra L. was induced in he laboratory by worsening the microclimate of the nest. A detailed analysis of the whole process is given; it is based both on observation and on traffic measurements between the old and the new nests. Three periods can be recognized: exploration, emigration, and final exploration. Two recruitment methods occur, initiated by distinct motor displays: group recruitment takes place first, whilst carrying behaviour becomes the main technique later. The organization of the group is described. The recruiter extrudes its sting while returning to the old nest and while leading the group. Tracks left on soot-coated glasses are analyzed. Sticks crushed with either the poison gland or the Dufour's gland are effective in leading the ants. Most adult carrying postures are typical for myrmicines: the occurrence of atypical postures is discussed. All the carrying acts (of brood and adults) are effected by 25% of the workers (on average); carrying activity is age-dependent. The stability of the group of carriers is tested during successive emigrations. Social regulation potentiality is strong: even queens or callows can move with their larvae when isolated from the rest of the colony.

Notes: Summary The reproductive rate of unmanaged European honeybee races was studied in Kansas, U.S.A. Colonies produced a mean of 3.6 daughter colonies per original queen during one year. This high reproductive rate was largely due to the frequent occurrence of afterswarms, a factor not adequately considered in previous studies. The rate of afterswarming was influenced by at least two factors: the amount of sealed brood (pupae) in the colony and the season when swarming occurred. Factors which may influence the survival and subsequent reproduction of prime swarms and afterswarms are discussed.

Notes: Summary The individual cell in the hornet or wasp comb is hexagonal in cross-section when it is one of the inner “ring” of cells. On the other hand, peripheral cells, like all cells built initially, have rounded rather than angled walls. This transformation from a goblet-shaped cell with rounded walls to an hexagonally-walled cell with an angle of 120° between each two walls is partly acheived by additional processing of the existing cell walls as new walls (between old and new cells) are accreted onto them from the outside. The comb cells are essentially hexagonal so that the “expenditure” in the building of the initial cell(s) is either 6 walls (in combs built around a single central cell) or 5.5 walls (where there are two abutting, central cells). With subsequent building, however, this “wall expenditure” diminishes gradually as more rings of cells are laid down, approaching an average value of 3 new walls per cell regardless of whether the comb is built around one or rather two central cells. Presented data on more efficient wall utilization in the larger combs offer further confirmation of the frugality of comb construction by Vespinæ.

Notes: Zusammenfassung Die typischen Außendiensttiere der roten Waldameisen (Formica polyctena Förster) verlassen das Nest spontan, auch bei gesättigten und ungestörten Völkern. Vermutlich haben sie nicht nur die Aufgabe, Nahrung zu sammeln, sondern auch, das Nestterritorium zu besetzen. Nach einem eintägigen Entzug von Zuckerwasser steigt die Anzahl der typischen Außendiensttiere, die sich jeweils außerhalb des Nestes aufhalten, und es beteiligen sich zusätzliche Außendiensttiere am Nahrungseintrag, die bei gesättigten Völkern das Nest nicht verlassen. Diese sind im Durchschnitt jünger als die typischen Außendiensttiere. Die Information über den Hungerzustand in einem Ameisenvolk wird zumindest teilweise durch ein Pheromon übertragen, das auch auf gesättigte Arbeiterinnen wirkt. Nach einem eintägigen Entzug von Zuckerwasser reagieren Ameisenvölker auf das Angebot einer 1 molaren Zuckerlösung mit einer Steigerung in der Anzhal der auslaufenden Arbeiterinnen. Gesättigte Völker reagieren nicht, und auch hungrige Völker reagieren nicht auf 0,1 molare Zuckerlösung und nur wenig auf Flüssigkeit aus zerquetschten Insekten. Die rekrutierten Arbeiterinnen unterscheiden sich anscheinend nicht von den oben charakterisierten zusätzlichen Außendiensttieren. Die Ameisen werden zumindest teilweise mit Hilfe eines Pheromons rekrutiert, das unabhängig davon wirkt, ob sie gesättigt oder hungrig sind. Der Inhalt von Dufourdrüsen oder seine Hauptkomponente, n-Undecan, bewirken eine ebensolche Auslaufsteigerung der Arbeiterinnen wie Duftstoffe aus einem alarmierten Volk. Ameisenvölker reagieren auch auf das Angebot von Beute mit einem Nahrungsalarm, und zwar über eine Entfernung von etwa 10 m zwischen Nest und Futterplatz. Da die Arbeiterinnen den Futterplatz meistens erst nach längerem Kampf (1–2 h) verlassen und nicht zu ihm zurückkehren, beginnt ein Nahrungsalarm zu Beute später und ist schwächer ausgeprägt als ein Nahrungsalarm zu Zuckerwasser. Deshalb ist dieses Verhalten nicht dazu geeignet, einzelne Beuteinsekten zu überwältigen, sondern dazu, Ansammlungen von Beutetieren zu nutzen.

Notes: Summary Social organization withinDictyna andMallos includes solitary species, species that live in groups and maintain territories (communal, territorial), and a group-living species (Mallos gregalis) that does not maintain territories (communal, non-territorial). Silk-mediated interattraction occurs inM. gregalis and in a communal, territorial species (Dictyna calcurata); but it does not seem to occur in another communal, territorial species (M. trivittatus), nor in a solitary species (M. niveus). Adult females ofM. gregalis were repelled by the silk of other dictynid species. All spiders that were tested were repelled by the silk of an araneid spider (Araneus diadematus).

Notes: Summary As in the red wood antFormica polyctena (Otto, 1958) the ovariole development inFormica sanguinea workers consists of eight stages well defined in time. This is revealed by investigations on workers of well known age. The undifferentiated tubes in young workers develop more and more into protuberant chambers, reaching a maximum growth around the fourth week. They then regress rather rapidly and after five weeks most ovarioles look like empty tubes containing some yellow bodies. Ovarioles of workers older than one year and a half, however, can be in various stages according to their physiological condition in the nest: foraging workers always have fully degenerated ovarioles, while the hibernating individuals still can have ovarioles in an early regression stage. The number of ovarioles seems to be related to body length: small individuals have on the average two ovarioles on each side, larger ones three to five.

Notes: Summary Workers and males of the stingless beeScaptotrigona postica emerge from morphologically similar cells. Normally only one bee is reared in each brood cell, but we found that some of the cells, interspersed throughout the brood comb, contained more than one egg. Because these additional eggs produced adult males, they were probably laid by nurse bees (workers) after the queen had oviposited in the cells concerned. Although there is no morphological difference between male and worker cells a significant difference was found in the amount of food inside them. The cell where the male is reared shows less food than the worker cell, difference that is statistically significant at 1% level. This fact suggests that: the worker might recognise the cell before oviposition and that this recognition is based on the difference of food quantity.

Notes: Summary The reproduction rate ofL. sakagamii is related to the queen density in each nest. In nests with higher queen densities, the ovarian development and the egg-laying rate of each queen is lower, though the number of eggs produced per nest is larger. In general, in nests with very high queen densities (more than about 25 queens per square meter of nest) or low worker/queen ratios (less than about 5,000 workers per queen), no alate queens are produced. Further, nests with high larva/worker ratios (more than about 5 larvae per worker) also produce no alate queens. On the other hand, the production of workers and males is larger in nests with high queen densities than in those with low queen densities.

Notes: Resume Chez la FourmiCataglyphis cursor, les ouvrières orphelines produisent par parthénogénèse des œufs reproducteurs plus volumineux que ceux des reines fécondées. On a étudié en élevage, l'évolution de la longueur des œufs dans des sociétés avec reine et des sociétés sans reine et tenté d'estimer le nombre d'œufs produits par des colonies d'effectifs variés. Dans les sociétés avec reine, les ouvrières restent stériles dans les conditions normales et la ponte royale est d'environ un millier d'œufs dans la saison; il peut se former des jeunes reines et des mâles, mais il apparaît surtout beaucoup de nouvelles ouvrières. Dans les sociétés orphelines, les ouvrières pondent un grand nombre d'œufs, élèvent en priorité des jeunes reines, parfois des mâles et moins de nouvelles ouvrières. Il n'existe pas d'œufs préorientés. C'es l'état physiologique des ouvrières nourrices qui conditionne de devenir reine ou ouvrière des larves femelles: dans le cycle normal, les ailés sont issus des œufs du début de ponte, qui sont les plus gros; mais des œufs tardifs et de plus petite taille peuvent aussi donner des reines si les larves qui en sont issues sont élevées par des ouvrières dont l'ovaire est en activité. Cela est particulièrement évident dans les sociétés orphelines où l'on peut obtenir des reines à partir d'œufs pondus onze semaines après le début de la ponte.

Notes: Summary Field studies ofNeivamyrmex nigrescens were conducted to determine how recruitment to, location and amount of food affect emigration frequency, distance and direction. Observations of foraging showed that emigrations were usually preceded by raids, proceeded over a successful raid column, and terminated near raid sites. Recruitment to food was not a necessary prelude to emigration, however, nor did emigrations always move to an area of heavy raiding. The new nest was not usually formed in a raid site, and there was a short latency from the discovery of the nest site to the onset of the emigration. Direction, distance, and timing of emigrations were related more directly to discovery of nest sites than raid sites, suggesting separate recruitment mechanisms. Because both raids and emigrations were eliminated by overfeeding of colonies, these behaviors share a common motivating factor, namely, brood stimulation. The interplay between general arousal from the brood and recruitment to specific stimuli promotes efficient use of surface activity time and prevents unnecessary exposure of queen and brood. The tendency to emigrate into areas of heavy raids results from the discovery of a nest in that area; thus a colony generally follows its food supply. Emigrations interfere considerably with raiding, however, and probably evolved under ecological conditions very different from the present study.

Notes: Summary Mandibular glands of the ant,Wasmannia auropunctata, contain 2,5-dimethyl-3-isopentylpyrazine, a compound which attracts nestmates to disturbed workers. During interspecific aggressive encounters, this small ant may utilize the alkylpyrazine as a repellent as well as disabling opponents with its potent sting venom. Alkylpyrazines have been previously identified as cephalic products from ants of the subfamilies Ponerinæ, Formicinæ, and Dolichoderinæ but this is the first report of an alkylpyrazine from the mandibular glands of a member of the Myrmicinæ.

Notes: Resume Dans deux guêpiers dePolistes, placés au voisinage l'un de l'autre, on relève une série d'indices physiologiques et éthologiques sur l'ensemble des descendantes encore vivantes à la mi-juillet; les indices choisis concernent des paramètres physiologiques liés à la fonction ovarienne et des paramètres éthologiques exprimant des formes d'intégration à la vie de la colonie. L'analyse factorielle conduit à discerner un certain nombre de sous-populations, que l'on peut regrouper en deux grandes séries dont on propose une interprétation fonctionnelle: l'une s'orientant vers la fonction de ponte et l'autre vers la fonction d'entretien de la colonie. Malgré une analogie évidente, ces deux séries ne coïncident pas parfaitement avec les deux castes classiquement discernées dans le sexe femelle; leur divergence résulte d'une série de facteurs impliquant à la fois l'appartenance de caste des divers individus et des facteurs causaux immédiats dont la nature exacte reste à préciser.

Notes: Resume La récolte des fourmis granivoresMessor galla a été suivie pendant deux ans et demi, dans un milieu sahélo-soudanien où les graines sont produites une fois par an, à l'issue d'une courte saison des pluies, en quantités limitées et variables selon les années. La récolte des fourmis est très saisonnière. En début de saison sèche, lorsque les nouvelles graines de l'année arrivent à maturité, les fourmilières récoltent intensément et montrent une nette préférence pour certaines graines qu'elles mettent en réserve. Leur activité décroît ensuite et reste faible et irrégulière tout le reste de l'année; elles ramènent alors essentiellement les graines les plus abondantes du milieu environnant leur nid. Les récoltes annuelles des fourmilières étudiées ont varié, selon la taille des colonies, de 3×105 à 4×106 graines, et de 1 à 19 kg. Dans un quadrat suivi plus précisément, les fourmis ont récolté successivement chaque année en 1978–80, 1979–80 et 1980–81, 4, 5, puis 4 kg/ha de graines, ce qui a représenté 0,4, 1,7, puis 0,5% de la production annuelle de graines par la végétation herbacée. En 1978–79, 3 colonies étudiées ne semblaient pas avoir stocké dans leurs nids plus d'une année de récolte. La récolte des fourmis a varié dans le temps et dans l'espace en fonction des disponibilités du milieu entourant leur nid. Cette plasticité semble être une réponse adaptée à la variabilité saisonnière et interannuelle des disponibilités alimentaires.

Notes: Summary This field study examines the social behavior of five sympatric species of desert seed-eating ants (Pogonomyrmex barbatus, P. rugosus, P. maricopa, P. desertorum, P. californicus). The species differed significantly in measures of activity rhythms in various colony tasks, use of space around the nest yard, and reaction to disturbance. Species differences were related to the typical size of a colony's outside work force. The behavior ofP. rugosus, P. barbatus, andP. maricopa, which had larger outside work forces, emphasized territoriality and the acquisition of food; that ofP. desertorum andP. californicus, which had smaller outside work forces, emphasized the avoidance of contact with other colonies. Examining the patterns in colony behavior can illuminate interspecific relationships in desert ant communities.

Notes: Summary Shifts of females ofPolistes versicolor between adjacent nests were observed in Panama. In the first case, females of two neighboring nests frequently changed their positions and one female who had developed eggs in ovaries shifted between the nests repeatedly. In the second case, possibly all females shifted to a nearby nest after abandonment of their original nest and were accepted by females of the new nest. In the third case where workers shifted, relatedness between them and foundresses of the new nest was considered to be low. Behaviours accompanying the shifts are described.

Notes: Summary The life cycle of the myrmicine antPristomyrmex pungens was investigated. Colonies of this species are usually composed of several thousand small workers, although a few males (2–3 %) occasionally appear during June and July in mature colonies, and large workers with ocelli and abortive spermathecae (here termedergatoid queens) were observed extremely rarely. We found that the virgin small workers can lay eggs and that these develop into further small workers. Cerebral ganglion cells and oogonial cells had the diploid chromosome number (2 n=24), but the haploid number (n=12) was observed in oocytes at pachytene, and also in spermatocytes from the rare males. Males have functionally normal copulatory organs and their spermatogenesis is normal, but they probably do not mate, because small workers have no spermatheca and their copulatory organs are degenerative. These observations indicate that reproduction inP. pungens is carried out predominatly or, probably, wholly by the small workers and hence is thelytokous. We discuss the evolution of theP. pungens life cycle, pointing out the difficulty of applying the “queen” concept to this species or even in deciding whether or not it is “eusocial”. In view of the apparent genetic isolation between colonies, the mode of selection maintaining sociality in this case is probably interdemic group selection rather than kin selection.

Notes: Resume L'étude des positions et mouvements d'antennes qui accompagnent les transferts de substances d'une ouvrière de Fourmi à l'autre, au cours des contacts trophallactiques, pose le problème de la valeur de signal de ces différents actes. ChezCamponotus vagus, ces unités comportementales sont organisées de manière séquentielle. Il n'y a pas stéréotypie des séquences; on enregistre une grande variablité, en particulier chez l'ouvrière donneuse. D'autre part, il apparaît des différences dans l'organisation des séquences et leur variabilité, en relation avec la fonction sociale exercée par l'ouvrière (récolteuse ou nourrice). L'analyse du comportement trophallactique des deux partenaires, par plusieurs méthodes différentes (cinéma accéléré avec analyse image par image, emploi des radio-éléments avec enregistrement simultané des actes et du flux trophallactique, cross-corrélogrammes), a permis de montrer que leurs actes ne constituent pas, au niveau antennaire, un système précis de signaux et de réponses. Ceci n'exclut pas la possibilité que l'activité antennaire globale ait par sa structure une fonction de communication.

Notes: Summary For each of three species of dolichoderine ants, four mating system models were tested electrophoretically. The models tested were: (1) each colony is derived from one, singly-inseminated female, (2) each colony is derived from one female, inseminated twice, (3) colonies have two, coequal, singly-inseminated queens, and (4) colonies have three, coequal, singly-inseminated queens. From each of these models, expected frequencies of colonies of various genotypic compositions were calculated. Goodness of fit of actual colony types were then tested. Conomyrma insana colonies were shown to be monogynous. A large number of theConomyrma bicolor colonies studied are functionally polygynous. Polygyny occurs in all localities examined. Polygyny may also occur inIridomyrmex pruinosum. Its occurence may be less widespread than inC. bicolor.

Notes: Resume J'ai analysé, chez deux espèces de Fourmis Ponérines d'Afrique tropicale, les caractéristiques de la marche en tandem et les stimuli qui interviennent, agissant sur l'ouvrièreguide ou sur l'ouvrière recrutée, pour déterminer la mise en route ou le maintien des tandems. Pour le genreMesoponera, les tandems permettent le recrutement pour la capture d'une proie mobile et volumineuse, mais aussi pour le transport collectif d'un insecte mort qui ne peut être transporté par une seule ouvrière, — ou pour la chasse d'un grand nombre de petites proies, enfin pour la récolte d'une substance sucrée. Le genreHypoponera utilise le tandem pour recruter, mais uniquement lors du dépeçage d'une proie volumineuse. D'autre part, j'ai montré que chezHypoponera sp. le nombre de tandems peut dépendre de stimuli olfactifs déterminés, perçus dans le très proche environnement de la société. Par conséquent, la modification de certains éléments de l'environnement peut avoir une action spécifique sur la manifestation d'interactions complexes observées dans les sociétés de Fourmis.

Notes: Summary The responses of the four fire ant species found in Texas (Solenopsis aurea Wheeler,Solenopsis geminata Fabricius,Solenopsis invicta Buren, andSolenopsis xyloni McCook) to varied relative humidities were examined. Humidity preferences of worker ants were determined with a linear gradient chamber. Workers alone did not exhibit any hydrokinetic responses, whereas brood tending workers of all species tested showed a marked preference (negative hydrokinesis) for saturated atmospheres (near 100 % RH). The responses are presumably due to the broods' hogher susceptibility to desiccation.

Notes: Summary Because social parasites are relatively rare in tropical ant faunas, new or poorly known forms deserve special attention. TwoPheidole species evidently parasitic onP. indica are here described as new species from India (P. lanuginosa, P. parasitica), while a previously known northern South American form,P. microgyna Wheeler, is redescribed and evaluated as a possible parasite ofP. minutula or a closely related host species. Next, all of the nine certain or likely social parasites ofPheidole known worldwide are compared, and an anatomical parasitic syndrome is identified through character state analysis. The nine species appear to be independently evolved. The parasitic character states have tended to evolve within each of these species at different rates, and hence the evolution is interpreted as having been not only parallel among species but mosaic in nature within species (seetable I). In spite of the lesser irregularities in this pattern, an overall trend is evident: the first changes to occur were loss of the worker caste (a loss still incomplete in the overall slightly modifiedP. inquilina), reduction of size, lengthening of the scape, reduction of sculpturing on the body surface, and broadening of the postpetiole. These shifts were followed by reduction of the mandibles and the segments of the funiculus. The generaAnergatides andBruchomyrma, each based on a single extremely advanced species, are placed in synonymy underPheidole. The problematic generaHagioxenus, Parapheidole, andSifolinia are compared withPheidole and their status evaluated. The greater known diversity of parasitic ants in the temperate zones, as compared with the tropics, remains a key problem in the study of ant evolution. Whether the difference is genuine or an artifact of differential sampling cannot be determined until more intensive collecting is undertaken in the tropics.

Notes: Resume L'étude détaillée du polyéthisme par l'observation des activités individuelles dans une société deNeoponera (=Pachycondyla sensuBrown, 1973)obscuricornis a été suivie de la dissection de tous les individus. L'état ovarien de chaque fourmi est en relation avec son statut social dans la colonie: développé chez les sogneuses, l'ovaire a complètement régressé chez les fourrageuses. Ce phénomène s'observe aussi bien chez les femelles que chez les ouvrières, seul un faible polymorphisme ovarient permettant de distinguer les deux castes. Les implications évolutives d'une liaison entre les conduites parentales et l'aptitude à la ponte sont discutées.

Notes: Summary Genetic relationships of eight northern European yellowjacket species, representingVespula s. str. (therufa group),Paravespula thevulgaris group) andDolichovespula, are here studied by enzyme electrophoresis. The observed level of intraspecific genic variation is relatively low, and the southern Finnish populations show no clear-cut geographic differences. The allozyme characters are further used to construct phylogenetic trees by four tree-building techniques. It is suggested thatDolichovespula media is not phylogenetically closely related to other EuropeanDolichovespula species, and thatParavespula andVespula s. str. may not form a single monophyletic group. Two of the species studied,V. austriaca andD. omissa, are obligatory social parasites. In both cases the parasite is related to its host. This supports the hypothesis that the social parasite generally arises from the same ancestral stock as the host species.

Notes: Summary Mixed-species colonies ofPolyergus lucidus andFórmica schaufussi were studied in New York. Slave raids were conducted in late afternoon, past the peak in diurnal temperature. Multiple raids on differentFormica colonies were common, as were re-raids on the same colony. In laboratory nests, about 75% of the raidedFormica brood was eaten. Of 27 days on which raids occurred in the laboratory, 25 were onFormica nests souted on the day of the raid.Polyergus scouts are among the oldest individuals in the colony, and callows do not participate in scouting during the entire season of their eclosion. The group ofPolyergus workers that circle on the surface near the nest prior to raiding has a dynamic composition. The most frequent behavioral transition was from circling on one day to scouting on the next. The next most common change was from scouting to circling. The first scouting of the spring season occurred only one day after the appearance ofPolyergus larvae. The first slave raid was conducted 4 days later.Formica brood was present in freeliving colonies from 1–4 weeks earlier thanPolyergus brood in mixed nests. Although workers ofPolyergus were usually fed by regurgitation fromFormica, they occasionally drank and ate eggs independently. ThePolyergus queen was surrounded only byFormica workers.Polyergus eggs hatched into larvae in approximately 12 days, with the larval stage lasting an additional 9–12 days. Eclosion of callows took place within 20–23 days after pupation. Newly matedPolyergus queens follow slave raids and attempt adoption into target nests when theFormica are scattered during a slave raid. The process of budding was never observed.

Notes: Summary This work helps in the taxonomical distinction betweenGoniomma hispanicum andG. baeticum, through the use of multidimensional analyses which were carried out on ten variables defined in the venation system of the first pair of wings on the female and gave highly significative results.

Notes: Abstract The integral equation for the electromagnetic response of a sphere in a layered medium may be solved as follows. First, the unknown time harmonic electric field in the sphere is expanded in spherical vector waves. Secondly, the coefficients for these wave functions are found by a set of equations. The equations are found by multiplying the integral equation throughout by each wave function and integrating over the spherical conductor. Once the unknown coefficients have been determined, then the transient response may be found by taking the inverse Fourier transform. In carrying out the Fourier transform one learns that for most of the time range used in prospecting, only the lowest order vector wave function is significant. A study of the singularities of the spectrum of the transient shows that, for the time range considered, only a single branch cut is significant. There are no pole type responses. That is, the field does not decay exponentially. Previous studies of a sphere in free space reported only pole type responses. That is, at the later stages, the field decays exponentially. This study shows that, in order to model satisfactorily the effect of the host rock on transient electromagnetic fields, the sphere must be placed in layered ground.

Notes: Abstract Tidal records at Hanasaki, southeastern Hokkaido, are analysed to clarify the post-seismic crustal vertical movement in the 1973 Nemuro-oki, Japan, earthquake. The result shows that the post-seismic uplift, as speculated byKasahara (1975), terminated in late 1975 and reverted to the previous rate of rapid subsidence of about 1 cm/yr. Ceasing of the post-seismic uplift, which occurred much earlier than previously speculated, could be explained by supplementary mechanisms, such as frictional resistance against creeping at the fault surface. This unexpected mode of movement, however, raises a new question about the accumulation of tectonic movements in this district. Since the subsidence rate extrapolated from geomorphological data for the past several thousand years is almost one order of magnitude lower than the recent rate as mentioned above, we have to provide some alternative explanation for the discrepancy between the two rates. In other words, simple repetition of co-, post- and inter-seismic movements in seismic cycles due to plate subduction, must be modified in this district. Several possible modifications to the subduction process are suggested, and a brief discussion of vertical movements expected in each case is given.

Notes: Abstract Recent advances in the use of dynamical and statistical models to forecast the weather are described. High resolution physical-mathematical models can now predict the development of synoptic weather systems in great detail for a few days ahead, while large-scale phenomena like blocking can be predicted for about a week or more. The local forecasting problem is presently being attacked by statistical- and meso-scale models using the large-scale predictions as input parameters. Very encouraging results have been obtained to predict the local weather, in particular when the local weather is influenced by topography and the underlying surface.

Notes: Abstract In recent years there has been much progress in describing and understanding the detailed dynamical and microphysical structure of frontal precipitation systems. In this article we consider phenomena on a hierarchy of scales: the broad synoptic-scale flows in mid-latitude depressions, the mesoscale patterns of precipitation, the nature and origin of convection at the surface and aloft, and the microphysical properties of the resulting precipitation. The influence of orography is also briefly discussed.

Notes: Abstract Spectral analyses were made of derived area-index series of areas subject to extreme temperatures and precipitation as well as cross-spectral analyses of the area-index series with double sunspot cycle (Zurich) numbers. Superposed epoch analyses also were made of area-index series versus various double-sunspot cycle phases. Area series for wet and dry Junes, warm Junes, defined June drought, and warm Januaries all show statistically significant double sunspot cycle (∼21 year) periodicities. The 21-year cycle of above-normal June precipitation is most striking and has not received previous recognition.

Notes: Abstract An examination is made of the hypothesis that internal cloud properties are determined by the mixing of dry air from above the cloud top and cloud base air in such a way that the mixture is neutrally buoyant with respect to the clear air environment at each level. It is concluded that the resulting mixture is much drier than is actually observed. Comments are made about observed cloud properties which need to be taken into account in any model of the mixing process.

Notes: Abstract Riming growth of ice particles is simulated by numerically solving the stochastic collection equations, simultaneously considering coagulation of water droplets. By introducing a special criterion which defines the habit of a riming particle, the influence of this habit on the growth of several kinds of ice particles assumed to be formed during riming was investigated. It was found that (i) hexagonal rimed ice plates are growing more efficiently than lump graupel or rimed columns, (ii) the use of different collection kernels for the lump graupel evolution leads to widely differing results and that (iii) the time dependent decrease of liquid water substance and the size of the resulting ice particles were more strongly influenced by the initial ice crystal concentration than by the initial ice crystal size and the habit of the ice particles. By decreasing the number density of ice crystals gradually a critical ice crystal concentration was found at which the present liquid water was not completely consumed by the riming process even after 1800 s model time, causing large drops of radii 〉100 μm to be formed in appreciable concentrations.

Notes: Abstract Helicopter measurements of solar irradiance and meteorological data within the atmospheric boundary-layer were made in Lagos during February 1979. Filter samples of aerosols were collected both during flight in February 1979 and at ground level in December 1978. Profile data on spectral aerosol optical depth were obtained and, from these, the aerosol extinction coefficient at two wavelengths (0.5 and 0.88 μm) were calculated. Precipitable water was low and was contained mainly within the 750 m layer above ground, suggesting the establishment of a deep unstable boundary layer. Calculated channel energy depletions by aerosols show that, within the first 750 m of the surface, the 0·88 μm might be more efficient at attenuating solar energy than 0·5 μm. The lagoon (maritime) aerosol sample indicated a more monodisperse size-distribution than the dusty harmattan aerosol sample.

Notes: Abstract The paper deals with an application of a stochastic model to the frequency and duration of precipitation events. With the aid of the model, the magnitudes ofmth highest rainfall amount in 24 hours' duration with 97.5% probability are obtained for various climatic regimes over a tropical monsoon region. There is good agreement between them-day minimum rainfall estimated through the model and the observed value. The model satisfactorily explains the frequency of the extreme rainfall event.

Notes: Abstract The study examines the correlation function of tropical monsoon rainfall on monthly, seasonal and annual time scales and obtains the relationship between this function and the distance. The area selected for study is Vidarbha with a fairly dense network of rain gauges. Vidarbha is a meteorological sub-division of the state of Maharashtra in India. Utilizing the relationship between the correlation function of the rainfall field and the distance, the errors of optimum interpolation of rainfall at a point have been computed by applying the method of optimum interpolation byGandin (1970). Relationships between the errors of interpolation and distance have been evaluated and from this the maximum spacing allowed between rain gauges for a specified tolerable error in interpolation has been estimated for each of the periods.

Notes: Abstract Square plate models with a diagonally located slit in compression were studied photoelastically. The resulting stress field surrounding the discontinuity (slit) is evaluated before and after seismoactive (seismic-energy-releasing) shear displacement. The mechanism of the fast shear movement (stick-slip), including its radiation properties, in interpreted. The results confirm the existence of a central locked zone in the loaded slit, the limits of which coincide with the initiation points of stick-slip movements. The zone is interpreted as the source of the seismic energy release. The complementary measurements (direct optical and ultrasonic) are presented to verify the results of the photoelastic analysis. The results obtained are discussed in regard to the conclusions that follow from the theory of elasticity.

Notes: Abstract Total ozone data series for 1957–82 at ten locations were subjected to Maximum Entropy Spectral Analysis. Besides the annual, semi-annual, and quasi-biennial oscillations, peaks were noticed at 3.5–4, 6–7, and 10–11 years. For Arosa, Switzerland, for a longer period (1932–71), an additional peak was indicated at about 16 years.

Notes: Abstract The temporal variation in precursory ground tilt prior to the 1944 Tonankai (Japan) earthquake, which is a great thrust-type earthquake along the Nankai Trough, is discussed using the analysis of data from repeated surveys along short-distance leveling routes.Sato (1970) pointed out that an anomalous tilt occurred one day before the earthquake at Kakegawa near the northern end of the focal region of the earthquake. From the analysis of additional leveling data, Sato's result is re-examined and the temporal change in the ground tilt is deduced for the period of about ten days beginning six days before the earthquake. A remarkable precursory tilt started two or three days before the earthquake. The direction of the precursory tilt was up towards the south (uplift on the southern Nankai Trough side), but the coseismic tilt was up towards the southeast, perpendicular to the strike of the main thrust fault of the Tonankai earthquake. The postseismic tilt was probably opposite of the coseismic tilt. The preseismic tilt is attributed to precursory slip on part of the main fault. If similar precursory deformation occurs before a future earthquake expected to occur in the adjacent Tokai region, the deformation may help predict the time of the Tokai earthquake.

Notes: Abstract During three years preceding the 1976 Friuli earthquake, a continuous southward ground tilt was recorded by a tiltmeter placed near Tolmezzo, 15 km north-west of the epicentre of the impending earthquake. The cumulative ground tilt amounted to as much as 3 minutes of arc. Since the tiltmeter was placed in the proximity of an active fault, such a tilt can be explained if the fault slipped aseismically on its shallower section during the same three year period. Aseismic slip on the fault might have been caused by the same mechanism which concentrated stress in the region and eventually produced the 1976 earthquake.

Notes: Abstract The locked section of the San Andreas fault in southern California has experienced a number of large and great earthquakes in the past, and thus is expected to have more in the future. To estimate the location, time, and slip of the next few earthquakes, an earthquake instability model is formulated. The model is similar to one recently developed for moderate earthquakes on the San Andreas fault near Parkfield, California. In both models, unstable faulting (the earthquake analog) is caused by failure of all or part of a patch of brittle, strain-softening fault zone. In the present model the patch extends downward from the ground surface to about 12 km depth, and extends 500 km along strike from Parkfield to the Salton Sea. The variation of patch strength along strike is adjusted by trial until the computed sequence of instabilities matches the sequence of large and great earthquakes sincea.d. 1080 reported by Sieh and others. The last earthquake was theM=8.3 Ft. Tejon event in 1857. The resulting strength variation has five contiguous sections of alternately low and high strength. From north to south, the approximate locations of the sections are: (1) Parkfield to Bitterwater Valley, (2) Bitterwater Valley to Lake Hughes, (3) Lake Hughes to San Bernardino, (4) San Bernardino to Palm Springs, and (5) Palm Springs to the Salton Sea. Sections 1, 3, and 5 have strengths between 53 and 88 bars; sections 2 and 4 have strengths between 164 and 193 bars. Patch section ends and unstable rupture ends usually coincide, although one or more adjacent patch sections may fail unstably at once. The model predicts that the next sections of the fault to slip unstably will be 1, 3, and 5; the order and dates depend on the assumed length of an earthquake rupture in about 1700.

Notes: Abstract After briefly reviewing the observational data on the stratospheric sulfate aerosol layer, the chemical and physical processes that are likely to fix the properties of the layer are discussed. We present appropriate continuity equations for aerosol particles, and show how to solve the equations on a digital computer. Simulations of the unperturbed aerosol layer by various published models are discussed and the sensitivity of layer characteristics to variations in several aerosol model parameters is studied. We discuss model applications to anthropogenic pollution problems and demonstrate that moderate levels of aerospace activity (supersonic transport and space shuttle operations) will probably have only a negligible effect on global climate. Finally, we evaluate the possible climatic effect of a ten-fold increase in the atmospheric abundance of carbonyl sulfide.

Notes: Abstract Solar radiation of λ〉175 nm and of Lyman-alpha at 121.6 nm is absorbed in the mesosphere and stratosphere by molecular oxygen (λ〈242 nm) and also by ozone molecules at λ〉200 nm. This paper describes the photodissociation processes resulting from absorption in the Schumann-Runge bands and Herzberg continuum of molecular oxygen and also in the Hartley, Huggins and Chappuis bands of ozone. Special consideration is given to differences between the stratospheric and mesospheric problems.

Notes: Abstract The catalytic destruction of stratospheric ozone by the oxides of nitrogen is believed to be an important part of the global ozone balance. The lack of sufficient measurements of NO x concentrations has impeded efforts to quantify this process. Recent measurements of stratospheric nitrogen dioxide from ground-based stations as well as aircraft and balloons have provided a first approximation to a global distribution of NO2 vertical columns at sunset. These observed vertical columns have been translated into time-dependent vertical NO2 profiles by means of a one-dimensional atmospheric photochemical model. Using recent observations of air temperature and ozone along with this information, the independent instantaneous (one second) rates of ozone production from oxygen photolysis P(O3), of ozone destruction from pure oxygen species (Chapman reactions) L(O x ), and of ozone destruction by nitrogen oxides L(NO x ) were estimated over the three-dimensional atmosphere. These quantities are displayed as zonal average contour maps, summed over various latitude zones, summed over various altitude bands, and integrated globally between 15 and 45 km. Although the global summation between 15 and 45 km by no means tells the complete story, these numbers are of some interest, and the relative values are: P(O3), 100; L(O x ), 15; L(NO x ), 45±15. It is to be emphasized that this relative NO x contribution to the integrated ozone balance is not a measure of the sensitivity of ozone to possible perturbations of stratospheric NO x ; recent model results must be examined for current estimates of this sensitivity.

Notes: Abstract An assessment is made of the relative contribution of certain classes of energetic particle precipitation to the chemical composition of the middle atmosphere with emphasis placed on the production of odd nitrogen and odd hydrogen species and their subsequent role in the catalytic removal of ozone. Galactic cosmic radiation is an important source of odd nitrogen in the lower stratosphere but since the peak energy deposition occurs below the region where catalytic removal of O3 is most effective, it is questionable whether this mechanism is important in the overall terrestrial ozone budget. The precipitation of energetic solar protons can periodically produce dramatic enhancement in upper stratospheric NO. The long residence time of NO in this region of the atmosphere, where catalytic interaction with O3 is also most effective, mandates that this mechanism be included in future modelling of the global distribution of O3. Throughout the mesosphere the precipitation of energetic electrons from the outer radiation belt (60°≲Λ≲70°) can sporadically act as a major local source of odd hydrogen and odd nitrogen leading to observable O3 depletion. Future satellite studies should be directed at simultaneously measuring the precipitation flux and the concomitant atmosphere modification, and these results should be employed to develop more sophisticated models of this important coupling.

Notes: Abstract Using standard ‘two-scaling’ techniques we calculate the Eulerian- and Lagrangianmean flows induced at second order in amplitude by small-amplitude, transient, non-dissipative, vertically-propagating inertio-gravity waves on anf-plane. The example is an idealized one, but illustrates a number of important features that are typical of wave, mean-flow interaction in a rotating, stratified fluid. Physical discussion of the solution is given in Section 4 of the review byMcIntyre (1980), which appears elsewhere in this issue.

Notes: Summary This article analyzes the nature of the aerosol information that current or planned spacecraft measurements could contribute toward the required input data for studies of natural anthropogenic influences on the middle atmosphere, and their consequent effects on our weather and climate. The analysis is conducted with particular reference to the solar occultation sounding technique as applied by the SAGE I experiment on the Atmospheric Explorer Mission B spacecraft. Its conclusions should prove to be of use in both the interpretation of the SAGE I data, and in the design of the follow-on mission on the Earth Radiation Budget satellite. Our analysis shows, in particular, that further studies are required in: the choice and number of sounding channels; the data taking sequence in relation to the atmospheric regions probed; the accuracy and vertical resolution of the atmospheric profiling, and their dependence on both the instrument/spacecraft parameters and the data inversion techniques; and the data reduction procedures. Neither of the selected channels is in a one-to-one relationship with an atmospheric constituent; hence, unless further assumptions are introduced, inversion techniques based on such a property are not applicable. The aerosol wavelengths are not satisfactory as they are only sensitive to the large size tail of the aerosol size distribution rather than to the predominant sizes; for these, UV wavelengths would be required. Owing to the change of the Sun's shape due to atmospheric refraction as the Sun either sets or rises, the higher altitudes will be scanned fewer times than the lower altitudes. Also, because transmission approaches rapidly unity above ∼40 km, the same high altitudes are more sensitive to measurement errors-errors that will propagate to lower altitude determinations when inverted profiles are reconstructed from the top of the atmosphere. These two factors, combined with the small air mass values at the high altitudes, are the cause of the mathematical ill-conditioning of the inversion problem. They point toward the need for a data-taking sequence strategy that would trade off between data storage and transmission constraints, larger accuracy at the high altitudes, and proper division of the atmosphere in order to overcome the ill-conditioning. Likewise, and as a result of the above considerations, there is a need for a detailed trade off study between data accuracy and vertical resolution of the reconstructed profiles. This should take into account the seasonal and geographical variations in the distribution of atmospheric constituents, as well as a representative statistical set at any given location and time, appropriate error measures and their vertical profiles, and several inversions utilizing as initial guesses profiles that depart from the true ones. It is also shown that the aerosol and ozone number densities cannot be recovered simultaneously without introducing some formula for the aerosol extincition or assumptions on the form of the aerosol size distribution. This problem is not resolved by the addition of sounding channels because each such channel introduces an additional unknown aerosol extinction. Thus, one is led to a separate rather than a simultaneous determination of the various constituents by resorting to complementary measurements. For a future experiment, it is suggested to determine the ozone separately from measurements at a close pair of appropriate wavelengths between which the aerosol extinction varies slowly whereas that of ozone exhibits a rapid variation. A similar technique could also be used for the separate determination of NO2. The relaxation-type of inversion suggest byChu andMcCormick (1979) does not seem to be appropriate because each channel is not sensitive selectively to an individual constituent, the aerosol channels are not sensitive to the important sizes in the distribution, and the sensitivity of the channels to the constituents of interest varies greatly with altitude. In the retrieval of the vertical profiles, the cause of the ill-conditioning of the inversion is identified. Two approaches are suggested for overconing this problem: (i) build the profile starting from the top of the atmosphere (forward procedure) but with an initial layer of sufficient air mass, or preferably (ii) reconstruct the profile from the lowest altitude reached (backward procedure) with a renormalization at the top of the atmosphere. In this process, the minimization search method (Fymat, 1976) would appear to be a better technique than the onion-peeling technique, as demonstrated byMill andDrayson (1978). In order to maximize the scientific return of SAGE I, a data inversion procedure is proposed. It assumes that (i) there are no aerosols above ∼25 km, and no NO2 below this altitude (as suggested byChu andMcCormick, 1979), (ii) below ∼25 km, ozone (and NO2, if present) could be determined separately, and (iii) the aerosol has a known refractive index at all wavelengths of interest, is assumed to be spherical (or describable in terms of ‘equivalent spheres’), and the minimum and maximum radii of its size distribution are known a priori. Under these assumptions, it is possible to retrieve the neutral density, NO2 and O3 profiles above ∼25 km, by either the forward or the backward procedure described above. Taking into consideration the power law variation of the air density with altitude, it is further possible to reconstruct the corresponding profiles at all the lower altitudes from the determinations in the altitude range ∼30–40 km. Below ∼25 km, the four SAGE I channels would then all become available for the aerosol inversion. While the profile reconstruction could proceed as for the higher altitudes, the aerosol inversion at each individual altitude presents problems of its own. Results of numerical experiments for aerosol inversion using all four SAGE wavelengths and seven different inversion routines are presented. If good a priori information is available on the sought size distribution solution, reasonably satisfactory inversions can be performed (see line 1 of Table 2, and Fig. 3c and 3d). However, in the absence of such information, there are as many solutions as inversion methods tried, in complete conformity with the well-known ill-conditioning of the problem. Among methods providing physically meaningful solutions, no method could be singled out as preferable to the others. In these inversions, the data were assumed to be exact, and 99% of the distribution were used. Under different conditions, the nonuniqueness of the inversion would be further compounded. Lastly, based on the present study, a strategy is suggested for the design and data interpretation of a follow-on SAGE-type experiment. Considering the important advantages to this problem presented by forward scattering, as demonstrated byFymat andMease (1978), a composite (extinction-forward scattering) experiment is recommended for the future experiments.

Notes: Abstract Solar radiance measurements covering over seventeen months are analysed for a location beside the Lagos Lagoon. The aerosol extinction coefficient was generally higher in the dusty months than in the wet months. ‘Clean air’ estimates of the coefficient are made. Data on its wavelength dependence are also presented.

Notes: Abstract Phase velocities of Rayleigh waves for the Adriatic Sea area are obtained in the period range 25–190 sec along the path (l'Aquila-Trieste) AQU-TRI and 20–167 sec along the path (Trieste-Bari) TRI-BAI. The phase velocities are systematically higher than the known values for the surrounding regions. The data inversion indicates the presence of a lithosphere typical of stable continental areas with clear high-velocity lid (V s ∼4.6 km/sec) overlying a well developed low velocity zone (V s ∼4.2 km/sec).

Notes: Abstract Model uncertainty is introduced into direct-current resistivity data by adding random changes to layer thicknesses in a ten-layer model. The resulting information is then aliased by generating a sounding curve which contains less information than the ten resistivities and nine thicknesses. These sounding curves are then inverted via the Backus-Gilbert algorithm using singular value decomposition to obtain solutions in terms of simpler two-or three-layer models. Quantitative results confirm what has been known qualitatively for many years as the principle of equivalence. An interesting result is that the geometric average of a given suite of noisy models is virtually identical to the best-fit model for the average of the noisy curves. The results show that the inversion of resistivity data by nonlinear least-squares parameter fitting is stable in the sense that noise in the data inverts to the same magnitude of noise in the model.

Notes: Abstract Results are presented from a two-dimensional, time-dependent model of the atmosphere which has been used to investigate perturbations to the ozone layer due to chlorofluorocarbons. The unperturbed stratosphere is modelled well with the observed features of the ozone distribution reproduced. The main features of the perturbation calculations are the large latitudinal and seasonal variations found in the modelled ozone reductions with greates reductions where the total ozone amounts are largest. The importance of at least a two-dimensional study in problems of this kind is stressed and the important role of dynamical and radiative processes, as well as chemical, is indicated.

Notes: Abstract The advective monthly mean transfer of water vapour in the layer below 700 mbar is investigated for India for the years 1962 to 1972 and for the months January to September. The average zonal and meridional components of the transfer of water vapour for India are obtained. They are further averaged for different combinations of the pre-monsoon months from January to May and are correlated with the summer monsoon rainfall. The correlation coefficients for zonal transfer of water vapour are either negative or small positive for different combinations of the months mentioned above. The correlation coefficients for the meridional transfer of water vapour are positive. The maximum value is 0.74 for the March to May combination and is statistically significant at the 1% level. An extensive investigation is, therefore, made for the March to May averages of water vapour transfer for four broad regions of India. The parameters of water vapour transfer for these regions are compared with the threshold values and the prediction category, normal or drought, for the subsequent summer monsoon season is determined for all years. The correlation coefficient between the index of drought, as determined from parameters of water vapour transport and rainfall departure, is statistically significant at the 2% level.

Notes: Abstract The results of atmospheric electric measurements over a twenty year period (1961–1980) are reviewed for Ibadan situated in the tropical rain forest of Nigeria. The aim is to present the data in an easily accessible form.

Notes: Abstract For a thermal starting from rest, the scales of motion consistent with the initial conditions are given. An alternative time scale based on the motion of the thermal is derived. The anticipated similarity solutions for thermals are summarised and possible qualitative differences between solutions are given. Within this consistent framework previously published laboratory and numerical models of thermals are discussed. Reasons why numerical models have not rigorously demonstrated the existence of a self-similarity solution are considered. Comparisons of all available results show that a single similarity solution valid for all thermals does not exist.

Notes: Abstract The measurement of the atmospheric electric field was carried out with a field mill at a small island in a bay on the Pacific coast of Japan. The data obtained during 80 months from 1971 to 1977 were analysed. It was found that characteristically the diurnal variation regularly alters with the seasons. Whereas the electric field in winter has the same diurnal pattern as that observed at globally representative stations, it exhibits in summer a pattern depending on the variation of the local electric conductivity. The alteration is inferred to be associated with regional atmospheric conditions surrounding the observation site.

Notes: Abstract This paper examines the evidence for the model of a small cumulus cloud represented as a quasi static but turbulent entity, growing on the upshear side and decaying on the downshear side. While the air just outside the cloudy outline is, on average, stationary relative to the embedding airmass, there is a slight flow, upwards and forward as though the updraft has induced upward motion in the clear air outside the cloud, on the growing side. On the decaying side the motion is downwards and away from the cloud. This is a flow pattern which is not consistent with the air flowing around the cloud as it moves forward but it agrees well with the picture given. Decayed remnants of cloud are found throughout the air previously occupied by the cloud. The cloud outline moves through the embedding air at a velocity which is almost as large as the relative motion of the subcloud feeding airflow (which is almost free from internal wind shear in strong convection). The mixing of dry air from above the inversion yields the observed diluted liquid water content in small cumuli, if such mixing is allowed to proceed until the cloud density equals that of the surrounding air. Quantitative conditions relating the liquid water to inversion temperature and moisture changes, and to the stability of the environment are presented. The strong vertical mixing from the top of the cloud downwards is important to microphysical processes.

Notes: Zusammenfassung Die Anfangsadjustierung der atmosphärischen Zustandsvariablen und die sehr kleinen Rechenzeitschritte sind Kernprobleme der numerischen Simulation von grossräumigen Wetterentwicklungen auf der Basis strenger hydrodynamischer Vorhersagemodelle. In dem vorliegenden Aufsatz wird ausführlich diskutiert wie beide Prognosehindernisse mit geeigneten Verträglichkeitsbedingungen (diagnostische Differentialgleichungen) zwischen den atmosphärischen Feldgrössengemeinsam beseitigt werden. Diese Bedingungsgleichungen sind gleichzeitig verwendbar, um (1) die Anfangsfelder der meteorologischen Variablen so aneinander anzupassen, dass kurzperiodische Lärmeffekte weitgehend unterdrückt werden (ungefilterte Systeme) (2) originäre Modellgleichungen zu ersetzen, so dass die meteorologisch irrelevanten Lärmwellen (mit lästig kleinen Zeitschritten) in den mathematischen Lösungen eliminiert werden (gefilterte Systeme). Die konsequente Nutzung der Lärmfiltertechnik führt (bei einem vertretbaren mathematischen Aufwand) in der Praxis dazu, dass während des numerischen Lösungsprozesses Lärmwellenanteile bis zur Unwirksamkeit reduziert und meteorologisch relevante Rossby-Wellen hinreichend gut konserviert werden. Die Praktizierbarkeit der Lärmfiltertheorie wird an einem (barotropen) 1-Schichtenprognosemodell rechnerisch realisiert und veranschaulicht. Die Kernprobleme der Initialisierung und der Lärmfilterung (Zeitschritt) werden dabei separat diskutiert.

Notes: Abstract Atmospheric mercury concentrations were measured during a nautical expedition on the Atlantic Ocean between Hamburg (54°N, 10°E) and Santo Domingo (20°N, 67°W). In addition, samples were taken during flights on a commerical aircraft in the upper and middle troposphere between 60°N and 55°S, mostly over the Pacific Ocean. The data obtained in the lower troposphere over the Northern Atlantic show considerable variation in the Hg concentrations, with values ranging between 1 and 11 ng/m3; the average concentration was found to be 2.8 ng/m3. The upper tropospheric data show an interhemispheric difference with average values of 1.45 ng/m3 and 1.08 ng/m3 in the Northern and Southern Hemisphere, respectively. This suggests that mercury production occurs predominantly over the continents both by natural and anthropogenic processes. The mercury content in aerosols was found to be ≤0.3 ng/m3, or one-tenth of the atmospheric concentration. The data indicate a mean residence time of mercury in the atmosphere of a few months to one year.

Notes: Abstract Compressional and shear-wave velocities (V p andV s ) were measured during the generalized triaxial deformation (i.e.σ 1≠σ 2=2σ 3) of pyrophyllite. Observed velocity changes could be ascribed to crack development during dilatancy. Velocity changes were very localized with respect to the ultimate failure plane. The orientation and development of the failure plane was continuously observed with laser holography. Velocity reverals, i.e. changes from a decreasing trend to an increasing trend, were documented in a wet sample in bothV p andV s . These changes in bothV p andV p are inconsistent with dialatancy-diffusion models. The reversals were interpreted as a reflection of local stress reorientation caused by a slowly propagating fault.

Notes: Abstract Meteorological rocket soundings, launched between 1968–74 at six locations representative of low, middle, and high latitudes in the northern hemisphere, are employed to determine the vertical, meridional and off-diagonal components of the eddy diffusivity in the northern hemispheric statosphere and lower mesosphere. It is shown that the distribution of the vertical and meridional components of the eddy diffusivity are similar in the northern hemisphere, although the magnitude of the former is 107 smaller than that of the latter; the magnitude of the off-diagonal eddy diffusivity is about 103 smaller than that of the meridional eddy diffusivity. In the troposphere, a maximum eddy diffusivity occurs in the mid-latitude at about 7 km above the mean sea level for both the summer and winter seasons. In the stratosphere, a maximum eddy diffusivity occurs in the mid-latitude at about 33 km in the winter, but no maximum in the summer.

Notes: Abstract The results of numerical models or of new observational programs are checked by comparing them with past observations. Also, it is desirable that the eddy diffusion coefficients used in two-dimensional models be derived from the same data set as the circulation statistics which the model outputs are checked against, so that all results refer to the same atmospheric conditions. For the first time, the three components of the eddy diffusion matrix, from 30–60 km, 80°N–10°S are computed, together with the means, variances and covariances of the wind and temperature through the same region using the same data set for 1960–76 and the same handling and analysis methods for all variables. Horizontal diffusivities,K yy , are obtained from the variance and integral time scale of the meridional wind speed. The present values are generally smaller than past estimates, presumably because temporal variations longer than a month have been removed in this work. Estimates ofK yz are based on the tentative assumption that the diffusivity is proportional to the slope of isentropic surfaces, and estimates ofK zz are based on the assumption that small-scale gravity waves are primarily responsible for vertical mixing.

Notes: Abstract Computations of concentrations of minor stratospheric gases using a two-dimensional model of the stratosphere are reported. The model includes Rayleigh scattering. This results in an increase in the photodissociation rate computation time by a factor of 1.5. The effect of ground albedo is assessed by comparing our results with a calculation of photolysis rates for a constant albedo with latitude. Comparison of results with a reference model including only molecular absorption are also made. The largest differences (≲50%) occur in NO and OH. An approximate expression for including the effects of Rayleigh scattering and surface reflectance in multi-dimensional models is suggested.

Notes: Abstract It is shown how to retrieve the atmospheric ozone profile by means of ground based microwave measurements of the radiative intensity. Chahine's iteration method is used. The method is tested by a numerical experiment. The retrieval rms about the mean error is approximately 0.4 ppm. The required measurement accuracy for the brightness temperatures is ±0.01 K.

Notes: Abstract Values for mean precipitable water are computed for four seasons of the year and for different regions of the Southern Hemisphere. Relationships between surface dew-point temperature and precipitable water were studied for these regions. A harmonic analysis of our data on precipitable water is attempted. Out results are presented and discussed.

Notes: Abstract The paper defines the intertropical convergence zone. (ITCZ) in the Indian monsoon region during the northern summer, identifies it with the northern boundary of the advancing monsoon and suggests that its seasonal movement can serve as an indicator of onset, advance and withdrawal of the monsoon. Evidence suggesting the movement of the ITCZ which is associated with the equatorial trough of low pressure is indirectly furnished by an analysis of the isallobaric or height-tendency field which reveals a distinct gradient towards the north/south during period of advance/withdrawal of the monsoon. A comparative study of the dates of onset of monsoon during two successive years appears to suggest that some of the problems encountered in using rainfall as the sole criterion for determining the onset and advance of the monsoon may be over-come by using the ITCZ concept as proposed in the present paper. Attention is drawn to the effects of synoptic-scale disturbances on the normal dates of onset, advance and withdrawal of the monsoon.

Notes: Abstract A theoretical model is presented which allows computing the efficiency with which aerosol particles of 0.001 ≤r≤1 μm are collected by columnar ice crystals in air of various relative humidities, temperatures, and pressures. Particle capture due to Brownian diffusion, thermo- and diffusiophoresis is considered. It is shown that phoretic effects importantly determine the particle capture process of 0.01≤r≤1 μm. The various pressure-temperature levels studied are found to affect the collection efficiency only ifr〉0.1 μm. Comparison shows that water drops generally are better aerosol particle scavengers than columnar ice crystals.

Notes: Abstract A theoretical model is presented which allows computing the efficiency with which aerosol particles of radius 0.1≤r≤10 μm are collected by simple ice crystal plates of radius 50≤a c ≤640 μm in air of various relative humidities, temperatures and pressures. Particle capture due to thermophoresis, diffusiophoresis and inertial impaction are considered. It is shown that the capture efficiency of an ice crystal in considerably affected by phoretic effects in the range 0.1≤r≤1 μm. For aerosol particles ofr〉1 μm the efficiency is strongly controlled by the flow field around the crystal and the density of the aerosol material. Trajectory analysis also predicts that aerosol particles are preferentially captured by the ice crystal rim. Our theoretica results are found to agree satisfactorily with the laboratory studies presently available. Comparison shows that for the same pressure, temperature and relative humidity of the ambient air ice crystal plates are better aerosol particle scavengers than water drops.

Notes: Abstract The paper deals with the atmospheric gaseous nitrogen-compounds under special consideration of the ocean being a source for NH3. The distribution of NH3 and NH4 + in the ocean is discussed. Additionally a survey of measured marine pH-values is given. While in temperate latitudes the source-strength of the ocean seems to be low, no such statement can be made at present for tropical latitudes owing to lack of measurements.

Notes: Abstract A Fourier transformation of the magnetic field from a magnetized sphere allows a particularly simple interpretation of the parameters of the sphere. The depth to the centre and total magnetic moments of the sphere are related to the intercept and slope of the power spectrum. The horizontal centre and direction of magnetization are related to slope and intercept of the phase spectra in two perpendicular, horizontal directions. Examples with artificial data contaminated by various noise components are presented.

Notes: Abstract Ion exchange and flameless atomic absorption spectrophotometry methods were used to measure the concentrations of sodium, manganese, iron and silver in snow accumulating at several sites on the Antarctic continent. The results show that the ratio of Mn/Fe is consistently close to the crustal value at all sites. The silver concentrations observed suggest a different origin, probably oceanic. When referenced to sodium, the degrees of enrichment of silver, manganese and iron increase by factors of 8, 2 and 2 respectively over a distance of 500 km from the ocean, after changes in sodium are accounted for. Investigation of the heavy metal content of fresh falling precipitation occorring on the Ross Ice Shelf, has shown that more enhanced enrichments of silver, manganese and iron occur in this fresh precipitation by factors up to 100, than in samples of snow and firn collected from shallow (up to 2 meters depth) pits at the same locations. Because the occurrences of these precipitation types vary temporally and geographically, it seems apparent that the shear stress conditions in the near surface boundary layer need to be considered in studies of snow and ice chemistry, particularly in polar regions where the chemical composition of permanent snow and ice fields are often investigated for evidence of climatic change, of glaciological behavior and of origins of chemical constituents.

Notes: Abstract Rayleigh's principle and the concept of the local wave number have been utilised for the approximate determination of the dispersion of Love waves propagating in a laterally heterogeneous layer lying over a homogeneous half-space. The shear wave velocity and the rigidity in the surface layer have been assumed to decrease with the increase of the lateral distance from the origin. The range of validity of the dispersion equation obtained by this method has been examined critically. It was found that: (a) for existence of Love waves the minimum value of shear wave velocity in the layer must be less than that in the matter below, and (b) the phase velocity of Love waves decreases with the increase of the lateral distance from the origin.

Notes: Abstract TheP-arrival times of local and regional earthquakes that are outside of a small network of seismometers can be used to interpret crustal parameters beneath the network by employing the time-term technique. Even when the estimate of the refractor velocity is poorly determined, useful estimates of the station time-terms can be made. The method is applied to a 20 km diameter network of eight seismic stations which was operated near Castaic, California, during the winter of 1972–73. The stations were located in sedimentary basins. Beneath the network, the sedimentary rocks of the basins are known to range from 1 to more than 4 km in thickness. Relative time-terms are estimated fromP-waves assumed to be propagated by a refractor in the mid-crust, and again fromP-waves propagated by a refractor in the upper basement. For the range of velocities reported by others, the two sets of time-terms are very similar. They suggest that both refractors dip to the southwest, and the geology also indicates that the basement dips in this direction. In addition, theP-wave velocity estimated for the refractor of mid-crustal depths, roughly 6.7 km/sec, agrees with values reported by others. Thus, even in this region of complicated geologic structure, the method appears to give realistic results.

Notes: Abstract It is shown, through numerical experiments, that the effect of ignoring ellipticity and rotation of the earth when inverting free oscillation data in moment tensor studies, is to introduce spurious spectral components in the solution. For numerical simulation of the data conditions of the 1970 deep Colombian event the spurious part has isotropic and deviatoric components, besides a distortion in the phase spectra which may lead to artificial precursive source in the solution. The magnitude of the artificial isotropic component is of the order of 10% of the real source moment tensor, depending on the data set used in the inversion. Measuring the excitation of each mode at each station using the technique of integrating over the spectral peaks does not cancel completely the effect of multiplet splitting, in particular that splitting due to rotation of the earth. The effect of lateral heterogeneities was simulated by introducing arbitrary splitting parameters which produced scattering in the eigenperiods compatible with those observed. For that splitting the inversion rendered additional isotropic components. We conclude that the observed implosive precursor the the 1970 Colombian event could have been artificially introduced by ignoring rotation, ellipticity and lateral heterogeneities of the earth. A procedure to invert free oscillation data for an elliptical rotating earth is proposed. It could be applied to a laterally inhomogeneous earth if the excitation for that model could be computed. Its application to real data for the deep Colombian event indicates that we will need to improve our knowledge on the effect of rotation, ellipticity, lateral heterogeneities and anelasticity on free oscillation and their excitation in order to solve accurately for the six components of the moment tensor independently.

Notes: Abstract The precision of measurement of surface-wave phase velocities at very long periods has reached a point where the exact, rather than asymptotic, form of the spherical harmonics must be considered in order to compute theoretical phase velocities or phase delays. The zeroth-order (i.e. constant) polar phase shift afterBrune et al. (1961) applies only between stations antipodal to each other. Everywhere else a correction for incomplete polar phase shift must be applied even if the waves do not cross a pole between the stations. The correction can exceed one percent of the total phase delay and thus be of the same order as the expected regional anomalies. It depends on the epicentral distance on the signal period and on the focal mechanism; the latter dependence can make the practical application cumbersome. We derive first-order asymptotic formulae for the correction of local phase velocities and total phase travel times of Rayleigh waves.

Notes: Abstract Long-period recordings of dispersive Rayleigh waves along numerous station lines, or ‘profiles’, in Europe have for the first time permitted a uniform inversion of these observations based on a new method of phase velocity regionalization. Regional dispersion relations obtained by this method have then been subjected to a complete inversion procedure commonly known as the ‘hedgehog’ method. The results are presented in a map outlining the thickness of the lower lithosphere (‘lid’) and the shear (S) velocities in both the ‘lid’ and the asthenosphere ‘channel’. A comparison of these results with the minimum compressional (P) wave velocities in the asthenosphere and their corresponding depths provides an estimate of theV p /V s ratio for the asthenosphere in the European area.

Notes: Summary To derive the structure of the Lower Mantle, observations of P and S waves at epicentral distances beyond 90 degrees have been used. The arrival times and amplitude decay with distance proved to be a source of information to derive the structure near the core-mantle interface. These observations were compared with results of theoretical calculations based on full wave theory [1, 2, 5, 6]. Another important theoretical method is the reflectivity method [4]. Differences between the two methods have a direct bearing on the interpretation of the observations and therefore need to be investigated. In the two methods the wave propagation involved in diffraction is simulated in different ways. In this paper the importance of approximations involved in each of the methods will be discussed. For this purpose the calculation of the frequency-dependent decay with distance of diffracted SH waves has been chosen. The approximations are considered to be important both in P and SH diffraction. The advantage of studying SH waves is the simpler and more straightforward formulation.

Notes: Summary The SH body-wave spectrum of a deep earthquake, which occurred at the foot of the Kamchatka peninsula and was recorded in the Solomon Islands, presents a regular modulation. The distribution of minima in the amplitude spectrum, corresponding to jumps in the phase spectrum, conforms with that expected from the interference between direct and surface reflected waves. The strong dependence of the modulation on the focal depth, emerging from theoretical SH body wave spectra obtained with the contribution of the first 21 higher Love-wave modes, was used to investigate the focal depth of the event here considered. The value estimated, 140 km, agrees with an earlier focal depth determination by travel time data.

Notes: Abstract Shallow strike slip earthquakes on vertical faults are modelled as two-dimensional antiplane strain ruptures in a uniformly prestressed homogeneous halfspace. Behind the rupture front, which is specified, the stress drops to a lower value. The elastodynamic boundary value problem is solved with a finite difference method. Several cases are studied, which include symmetric and one-directional rupture propagation, surface faulting, multiple events, variable rupture velocity, sticking and rebreaking of the fault plane. The time function of displacement, velocity and acceleration are interpreted as signals generated by events in the focus, namely starting, stopping and breaking through the surface of the rupture. The model explains peak velocity and peak acceleration in the near field of M≈5.5–6 earthquakes; which are typically about 0.2 m/s and 5 m/s2 at 10 km epicentral distance, if the rupture velocity is close to the shear wave velocity. Sticking of the fault does not alter the accelerograms significantly, but it increases the seismic moment in simple events and decreases it in multiple events.

Notes: Abstract The paper discusses basic ideas and principles underlying methods, which have proved useful in the interpretation of diffraction and scattering phenomena by a smooth or slightly rough solid-liquid interface. Generally, the wave interaction may be formulated as an excitation problem; it involves (1) finding an equivalent dislocation or source distribution on the interface, and (2) evaluating the excited wave field. These steps are taken through perturbation theory and/or adopting the appropriate generalization of ray theory. In this context an explicit form of Green's function is also given. The methods have been applied to the core-mantle boundary, with a view toward the interpretation of recent data: (a) diffracted P and S waves around the core (in particular, their attenuation); (b) scattered short-period core phases (in particular, precursors to PKP and PKKP). Other types of wave interaction, and implications for models of the core-mantle boundary structure, are briefly mentioned.

Notes: Abstract The derivation of P and S velocities at the core-mantle boundary (CMB) from long-period diffracted waves by the use of the simple ray-theoretical formulav CMB=r c /p (v CMB=velocity at the CMB;r c =core radius;p=ray parameter) yields apparent velocity values which differ from the true velocities. Using a dominant period of about 20 sec for calculating theoretical seismograms, we found a linear relation between the apparent velocity and the average velocity in a transition zone at the base of the mantle with fixed velocity on top. The ray parameters determined from long-period earthquake data are found to be 4.540±0.035 and 8.427±0.072 sec/deg for Pdiff and Sdiff, respectively. These values yield apparent velocities of 13.378±0.103 for P and 7.207±0.062 km/sec for S waves. By means of the theoretical relation between apparent and average velocity and under the assumption of linear variation of velocity with depth, one can invert the apparent velocities into true CMB velocities of 13.736±0.170 and 7.320±0.124 km/sec. These results imply positive velocity gradients at the base of the mantle and hence no significant departures from adiabaticity and homogeneity.

Notes: Abstract Data from a reversed seismic crustal profile crossing the Caledonides of southern Norway suggest a continuously increasing P-wave velocity followed by a low-velocity zone extending from a depth of about 14 km downwards. Interpretation of observed travel time and amplitude characteristics leads to a thickness of 4 km and velocity of 6.0 km/s for this layer, the velocity above and below it being about 6.6 km/s. The role of such a velocity inversion is discussed in the tectonic framework of the Caledonian orogeny and other relevant geophysical information, and it is suggested that the low-velocity zone materializes deep-seated sediments under Precambrian crystalline rocks. The structure of the lower crust is more tentatively established, but still in reasonable agreement with other seismic investigations in the general profiling area.