The Intermediate Depth Waters of the Tasman and Coral Seas. III. Succession of Water Types East of Port Hacking in 1957-1959

1962 ◽  
Vol 13 (1) ◽  
pp. 61 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Seasonal Cycle ◽  
Vertical Mixing ◽  
Maximum Intensity ◽  
Water Type ◽  
Intermediate Depth ◽  
Water Types ◽  
South West ◽  
The Pacific ◽  
Actual Movement ◽  
The Antarctic

The seasonal occurrences of three water types on the 27.20 and 26.80 σt, surfaces on a section east of Port Hacking, 153-160� E., and at certain stations north of this line are discussed. On the 27.20 σt, surface it is shown that the Pacific Equatorial Intermediate is found in maximum intensity during September-October at longitude 158-160� E. Subsequently it moves west and during April-June it occurs at longitude 153-157� E. The South-West Pacific Intermediate appears at maximum intensity during March-July at 158-160� E. but in September-February it moves west to longitude 152-154� E. The Antarctic Intermediate is only about 30% of the water type mixture and occurs at the eastern end of the section during December to April and at the western end (152-154� E.) during March-April. On the 26.80 σt, surface the Subtropical formed between 30 and 75% of the water type mixture and was the principal water type, though it was not possible to distinguish between the part formed by local vertical mixing and that formed by actual movement from the Subtropical Convergence. No seasonal cycle could be determined for the Upper Antarctic Intermediate which varied between 0 and 55% of the water type mixture. The Upper Equatorial Intermediate varied from 5 to 45% of the mixture and showed no seasonal cycle.

The Intermediate Depth Waters of the Tasman and Coral Seas. I. The 27.20 σt Surface

1960 ◽  
Vol 11 (2) ◽  
pp. 127 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Dissolved Oxygen ◽  
Distribution Patterns ◽  
Equatorial Region ◽  
Intermediate Depth ◽  
Water Types ◽  
South West ◽  
The Pacific ◽  
Antarctic Convergence ◽  
Horizontal Mixing ◽  
The Antarctic

The distribution of salinity, dissolved oxygen, and phosphates on the 27.20 σt surface of the Tasman and Coral Seas is examined. Their distribution patterns and the relations of salinity and phosphate values on this σt surface are explained by the horizontal mixing of three water types. These originate, one at the Antarctic Convergence, one in the western equatorial region of the Pacific, and one in the south-west Pacific. From the distribution of these water types and the topography of the 27.20 σt surface, general features of the intermediate depth circulation of the Tasman and Coral Seas are deduced.

Origin and circulation of water types of the 25.00 sigma-t surface of the South-west Pacific

1969 ◽  
Vol 20 (2) ◽  
pp. 105 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Continental Margin ◽  
High Salinity ◽  
Vertical Mixing ◽  
Water Type ◽  
Subtropical Water ◽  
Water Types ◽  
Low Salinity ◽  
Tropical Water ◽  
South West ◽  
Mixed Transition

The salinity and oxygen of 25.00 sigma-t waters of the Tasman and Coral Seas have been averaged within 5� squares. From these average values four water types were identified by their salinity-oxygen relations. These were: a tropical high salinity (mean salinity 36.00‰, mean oxygen 3.50 ml/l.), a tropical low salinity (mean salinity 35.25‰, mean oxygen 3.10 ml/l.), a subtropical high salinity (mean salinity 35.75‰, mean oxygen 5.15 ml/l.), and a subtropical low salinity (mean salinity 35.46‰, mean oxygen 5.15 ml/l.). Waters north of 15�S. were all mixtures of the two tropical water types, and those south of 35� S. were all mixtures of the two subtropical water types. Topography of the 25.00 sigma-t surface showed easterly flow at around 15� S. and, as far as could be interpreted, easterly flow at 35� S. Between these two zones of tropical and subtropical water types there occurred a region of mixed transition waters in which large meridional gradients of oxygen but small gradients of salinity were found. This transition region occupied a much larger area off east Australia than elsewhere, mainly because there was greater meridional exchange of the tropical and subtropical water types off east Australia. North of 20� S. the high salinity subtropical water type spreads northward in the central Tasman and Coral Seas in summer and the low salinity tropical water type spreads southward along the Queensland continental margin in winter. South of 20� S. it was impossible to separate changes due to circulation from those caused by vertical mixing and winter formation of 25.00 sigma-t water at the surface.

The Intermediate Depth Waters of the Tasman and Coral Seas. II.The 26.80σt surface

1960 ◽  
Vol 11 (2) ◽  
pp. 148 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Distribution Patterns ◽  
Intermediate Depth ◽  
The North ◽  
Winter Distribution ◽  
South West ◽  
Tasman Sea ◽  
Antarctic Convergence ◽  
Horizontal Mixing ◽  
The Antarctic ◽  
The Western Pacific

The distribution of salinity, dissolved oxygen, and phosphates on the 26.80 σt surface of the Tasman and Coral Seas is examined. The distribution patterns of these properties and the relations of salinity and phosphate and salinity and oxygen values are explained by horizontal mixing of three water types. These originated, one to the north of the Antarctic Convergence, one in the south-west Tasman, possibly in the Australian Bight, and one at the equator in the western Pacific. The major sinking regions and the circulation paths of subtropical waters in the Tasman Sea are deduced from their summer and winter distribution and from the topography of the 26.80 σt, surface.

Origin and circulation of water types on the 26.00 sigma-t surface of the south-west Pacific

1968 ◽  
Vol 19 (2) ◽  
pp. 107 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Oxygen Content ◽  
Water Type ◽  
The South ◽  
West Pacific ◽  
Water Types ◽  
South West ◽  
Tasman Sea ◽  
Type 3

CSIRO hydrological data from the south-west Pacific (0-45�S., 140°E.-160� W.) during 1960-67 have been used to calculate annual means of salinity and oxygen, within 5� squares, on the 26.00 sigma-t surface. In addition, for some squares it was possible to calculate mean summer (December-February) and mean winter (July- September) values of salinity and oxygen. From the annual means the salinity-oxygen relations were used to characterize four water types. Water type 1 of tropical origin had a salinity of 35.03‰ and an oxygen content of 3.20 ml/l. Water type 2, also of tropical origin, had a salinity of 35.23‰ and an oxygen content of 2.30 ml/l. Water type 3 of subtropical origin had a salinity of 35 +66‰ and an oxygen content of 5.45 ml/l. Water type 4 of Subantarctic origin had a salinity of 34.80‰ and an oxygen content of 6.00 ml/l. The ultimate origins of water types 1 and 2 are thought to be at considerable distances from the south-west Pacific region. Water type 1 is suggested as a mixture of waters of the North Equatorial Pacific, to the west of about 160°W., and waters of type 3 originating in the south Tasman Sea and other regions of the south Pacific. Water type 2 forms at around 16O°W., by mixing of eastern tropical Pacific waters and water type 3. It is thought that water types 1 and 2 form at different times of the year depending upon the extent of meridional or zonal flow in the central Equatorial region. Water types 3 and 4, however, are formed by southward spreading and winter cooling at the surface of subtropical waters, and by northward spreading and summer warming at the surface of Subantarctic waters, respectively. These two water types are therefore of south-west Pacific origin. Generally in the Tasman Sea (south of 25�S.), the concentration of water type 1 is very low (less than 10%); of water type 2 only a little higher (20-30%), but that of water type 3 is high (around 60-75%). The concentration of water type 4 was much greater (40%) off the west coast of South Island, New Zealand, than off the east coast of Tasmania (15 %). Seasonal pulses in the concentrations of water types 1 and 2 along 170�E., between 0 and 15�S., are in phase with seasonal changes in the concentration of these two water types in the Tasman and Coral Seas, if these water types spread southward at about 10 cm/sec. Summer increases in the concentration of water type 3 in the Tasman Sea off New Caledonia have been explained by the northward spreading of the previous winter's accumulation of this water type in the central Tasman Sea.

El Nino Chaos: Overlapping of Resonances Between the Seasonal Cycle and the Pacific Ocean-Atmosphere Oscillator

Science ◽  
1994 ◽  
Vol 264 (5155) ◽  
pp. 72-74 ◽  
Author(s):  
E. Tziperman ◽  
L. Stone ◽  
M. A. Cane ◽  
H. Jarosh
Keyword(s):  
Pacific Ocean ◽  
El Niño ◽  
Seasonal Cycle ◽  
El Nino ◽  
The Pacific ◽  
Ocean Atmosphere ◽  
The Pacific Ocean

scholarly journals Amplitudes of surface waves and magnitudes of shallow earthquakes*

1945 ◽  
Vol 35 (1) ◽  
pp. 3-12
Author(s):  
B. Gutenberg
Keyword(s):  
Absorption Coefficient ◽  
Surface Waves ◽  
Epicentral Distance ◽  
Pacific Basin ◽  
Depth Of Focus ◽  
Intermediate Depth ◽  
Station Corrections ◽  
The Pacific ◽  
Shallow Earthquakes

Summary. A study of amplitudes of surface waves having periods of about 20 seconds is employed to improve the calculation of magnitudes of distant shallow earthquakes. Table 3 gives station corrections; table 4, revised figures for the effect of epicentral distance. It is found that for epicentral distances between about 20° and 175° the average observed amplitudes correspond closely to those calculated with an absorption coefficient k = 0.0003 per km. For paths completely outside or inside the Pacific Basin, k = 0.0002± per km., while for paths tangent to its boundary the amplitudes of surface waves with periods of about 20 seconds may be reduced by two-thirds or more (in extreme cases by almost nine-tenths) through reflection or refraction of energy; such seismograms of shallow shocks may be taken as indicating intermediate depth of focus.

scholarly journals Antarctic ice-shelf calving triggered by the Honshu (Japan) earthquake and tsunami, March 2011

2011 ◽  
Vol 57 (205) ◽  
pp. 785-788 ◽  
Author(s):  
Kelly M. Brunt ◽  
Emile A. Okal ◽  
Douglas R. MacAyeal
Keyword(s):  
Pacific Ocean ◽  
Northern Hemisphere ◽  
European Space Agency ◽  
Observational Evidence ◽  
Ice Shelf ◽  
Wave Impact ◽  
Space Agency ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Antarctic

AbstractWe use European Space Agency Envisat data to present the first observational evidence that a Northern Hemisphere tsunami triggered Antarctic ice-shelf calving more than 13 000 km away. The Honshu tsunami of 11 March 2011 traversed the Pacific Ocean in <18 hours where it impinged on the Sulzberger Ice Shelf, resulting in the calving of 125 km2 of ice from a shelf front that had previously been stable for >46 years. This event further illustrates the growing evidence of ocean-wave impact on Antarctic calving and emphasizes the teleconnection between the Antarctic ice sheet and events as far away as the Northern Hemisphere.

Chapter 3.1b Antarctic Peninsula and South Shetland Islands: petrology

2021 ◽  
pp. M55-2018-68 ◽  
Author(s):  
Philip T. Leat ◽  
Teal R. Riley
Keyword(s):  
Antarctic Peninsula ◽  
Continental Margin ◽  
Volcanic Rocks ◽  
Oceanic Lithosphere ◽  
Contact Metamorphism ◽  
South Shetland Islands ◽  
Calc Alkaline ◽  
The Pacific ◽  
High K ◽  
The Antarctic

AbstractThe Antarctic Peninsula contains a record of continental-margin volcanism extending from Jurassic to Recent times. Subduction of the Pacific oceanic lithosphere beneath the continental margin developed after Late Jurassic volcanism in Alexander Island that was related to extension of the continental margin. Mesozoic ocean-floor basalts emplaced within the Alexander Island accretionary complex have compositions derived from Pacific mantle. The Antarctic Peninsula volcanic arc was active from about Early Cretaceous times until the Early Miocene. It was affected by hydrothermal alteration, and by regional and contact metamorphism generally of zeolite to prehnite–pumpellyite facies. Distinct geochemical groups recognized within the volcanic rocks suggest varied magma generation processes related to changes in subduction dynamics. The four groups are: calc-alkaline, high-Mg andesitic, adakitic and high-Zr, the last two being described in this arc for the first time. The dominant calc-alkaline group ranges from primitive mafic magmas to rhyolite, and from low- to high-K in composition, and was generated from a mantle wedge with variable depletion. The high-Mg and adakitic rocks indicate periods of melting of the subducting slab and variable equilibration of the melts with mantle. The high-Zr group is interpreted as peralkaline and may have been related to extension of the arc.

The role of contact and language shift in the spread of Austronesian languages across Island Southeast Asia

2020 ◽  
pp. 167-194
Author(s):  
Mark Donohue ◽  
Tim Denham
Keyword(s):  
Southeast Asia ◽  
Marine Environment ◽  
Language Shift ◽  
Language Family ◽  
Austronesian Languages ◽  
Island Southeast Asia ◽  
South West ◽  
The Pacific ◽  
European Colonization

The spread of modern humans into and across Island Southeast Asia and the Pacific represents the earliest confirmed dispersal of humans across a marine environment, and involved numerous associated technologies that indicate sophisticated societies on the move. The later spread of ‘Austronesian’ over the region shows language replacement on a scale that is reminiscent of the period of state-sponsored European colonization, and yet the Austronesian languages present a typological profile that is more diverse than any other large language family. These facts require investigation. This chapter examines the separate, but intertwined, histories of the region. It shows that the dispersal of Austronesian languages, originating in Taiwan, should not be portrayed as a technological and demographic steamroller. This involves discussion of the nature of pre-Austronesian society and language in the south-west Pacific, and the degree to which it has and has not changed following ‘Austronesianization’.

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