Satellite observations of internal waves on the Australian north-west shelf

1981 ◽  
Vol 32 (3) ◽  
pp. 457 ◽  
Author(s):  
PG Baines
Keyword(s):  
New Zealand ◽  
Internal Waves ◽  
Wave Packets ◽  
Satellite Observations ◽  
North West ◽  
The North ◽  
Continental Shelves

This paper describes the results of a search of the existing Landsat (1 and 2) imagery catalogue for tidally generated internal waves over the continental shelves of Australia and New Zealand. The only area where such waves were observed was the Australian north-west shelf where they were found in abundance from the North West Cape to the latitude of Darwin. Wavelengths were in the range 300-1000 m with typical speeds of 0.5-1 m s-1, and spacing between wave packets of 25 km.

scholarly journals Effect of tropical cyclones on the Stratosphere-Troposphere Exchange observed using satellite observations over north Indian Ocean

2016 ◽  
Author(s):  
M. Venkat Ratnam ◽  
S. Ravindra Babu ◽  
S. S. Das ◽  
Ghouse Basha ◽  
B. V. Krishnamurthy ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tropical Cyclones ◽  
Lower Stratosphere ◽  
North Indian Ocean ◽  
Satellite Observations ◽  
Upper Troposphere ◽  
North West ◽  
The North ◽  
The Impact

Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere-troposphere exchange (STE) process in the Upper Troposphere and Lower Stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the North Indian Ocean during 2007–2013 on the STE process is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) Radio Occultation (RO) measurements and ozone and water vapor concentrations in UTLS region are obtained from Aura-Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km from the centre of cyclone. In our earlier study we have observed decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K) and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within the 500 km from the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from cyclone centre whereas the enhancement in the water vapor in the lower stratosphere is more significant on south-east side extending from 500–1000 km away from the cyclone centre. We estimated the cross-tropopause mass flux for different intensities of cyclones and found that the mean flux from stratosphere to troposphere for cyclonic stroms is 0.05 ± 0.29 × 10−3 kg m−2 and for very severe cyclonic stroms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed in the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget and consequentially the STE in the UTLS region.

scholarly journals Ormond earthquake liquefaction reconnaissance report

1993 ◽  
Vol 26 (3) ◽  
pp. 312-328 ◽  
Author(s):  
Steven A. Christensen
Keyword(s):  
New Zealand ◽  
Focal Depth ◽  
Strong Motion ◽  
North West ◽  
The North ◽  
Peak Ground Accelerations ◽  
Seismological Observatory

On August 10 1993, at 09h 46m UT an earthquake of magnitude (ML) 6.4 occurred near Ormond, a locality to the north west of Gisbome in the North Island of New Zealand. The epicentre of the event was 38.52°S, 177.93°E, and had a focal depth of 48 km (Seismological Observatory, Institute of Geological and Nuclear Sciences Ltd.). Strong motion accelerographs at two sites on sediment in Gisborne recorded peak ground accelerations of 0.22 g at a distance of 20 km from the epicentre, while at Wairoa (80 km to the SW of the epicentre) 0.05 g was recorded, at Tolaga Bay (30 km to the NE of the epicentre) 0.09 g was measured [Pers. Comn. J. Zhou], and strong motion lasted for 5-10 s. Intensity of MMVI was observed in the Ormond area with pockets of MMVII, the later being based in particular on the presence of liquefaction.

scholarly journals Dynamics of air–sea CO<sub>2</sub> fluxes in the North-West European Shelf based on Voluntary Observing Ship (VOS) and satellite observations

2015 ◽  
Vol 12 (7) ◽  
pp. 5641-5695 ◽  
Author(s):  
P. Marrec ◽  
T. Cariou ◽  
E. Macé ◽  
P. Morin ◽  
L. A. Salt ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Mixed Layer Depth ◽  
Satellite Observations ◽  
Gas Transfer ◽  
Co2 Fluxes ◽  
Transfer Velocity ◽  
Chl A ◽  
North West ◽  
The North ◽  
West European

Abstract. From January 2011 to December 2013, we constructed a comprehensive pCO2 dataset based on voluntary observing ship (VOS) measurements in the Western English Channel (WEC). We subsequently estimated surface pCO2 and air–sea CO2 fluxes in north-west European continental shelf waters using multiple linear regressions (MLRs) from remotely sensed sea surface temperature (SST), chlorophyll a concentration (Chl a), the gas transfer velocity coefficient (K), photosynthetically active radiation (PAR) and modeled mixed layer depth (MLD). We developed specific MLRs for the seasonally stratified northern WEC (nWEC) and the permanently well-mixed southern WEC (sWEC) and calculated surface pCO2 with relative uncertainties of 17 and 16 μatm, respectively. We extrapolated the relationships obtained for the WEC based on the 2011–2013 dataset (1) temporally over a decade and (2) spatially in the adjacent Celtic and Irish Seas (CS and IS), two regions which exhibit hydrographical and biogeochemical characteristics similar to those of WEC waters. We validated these extrapolations with pCO2 data from the SOCAT database and obtained relatively robust results with an average precision of 4 ± 22 μatm in the seasonally stratified nWEC and the southern and northern CS (sCS and nCS), but less promising results in the permanently well-mixed sWEC, IS and Cap Lizard (CL) waters. On an annual scale, seasonally stratified systems acted as a sink of CO2 from the atmosphere of −0.4, −0.9 and −0.4 mol C m−2 year−1 in the nCS, sCS and nWEC, respectively, whereas, permanently well-mixed systems acted as source of CO2 to the atmosphere of 0.2, 0.4 and 0.4 mol C m−2 year−1 in the sWEC, CL and IS, respectively. Air–sea CO2 fluxes showed important inter-annual variability resulting in significant differences in the intensity and/or direction of annual fluxes. We scaled the mean annual fluxes over six provinces for the last decade and obtained the first annual average uptake of −0.95 Tg C year−1 for this part of the north-western European continental shelf. Our study showed that combining VOS data with satellite observations can be a powerful tool to estimate and extrapolate air–sea CO2 fluxes in sparsely sampled area.

Field Observations and Modelling of the Self-Burial of a North West Shelf Pipeline

2003 ◽  
Author(s):  
Rodney Pinna ◽  
Andrew Weatherald ◽  
John Grulich ◽  
Beverley F. Ronalds
Keyword(s):  
Internal Waves ◽  
The Self ◽  
Field Observations ◽  
North West ◽  
The North ◽  
Hydrocarbon Fluid ◽  
Key Driver

The Goodwyn Interfield Pipeline was laid on the Australian North West Shelf, connecting the Goodwyn and North Rankin platforms, in 1993. It is operated by Woodside Energy Limited, and is used to transport hydrocarbon fluid from the Goodwyn and Echo/Yodel fields to the North Rankin A platform, which is connect to onshore processing facilities by the 140 km North Rankin trunkline. This pipeline was expected to self-bury along the majority of its length. After nine years however, some sections of the pipeline have experienced significant self-burial, however, other sections remain exposed. The first part of this paper details the results collected from annual surveys of the pipeline, while the second part looks at modelling the self-burial process. The effect of internal waves is found to be a key driver in the self-burial process.

Spilitic Rocks in New Zealand

1936 ◽  
Vol 73 (9) ◽  
pp. 414-423 ◽  
Author(s):  
J. A. Bartrum
Keyword(s):  
New Zealand ◽  
Focused Attention ◽  
North West ◽  
The North

Prior to a discovery made recently by the writer, of spilitic rocks at Great King Island, the largest member of the Three Kings group of islands, about 26 miles north-west of the north-west extremity of the mainland of New Zealand, such rocks had not previously been found in this latter country. Some account of the types represented at Great King Island may therefore be welcome, particularly since Gilluly's (1935) recent comprehensive paper has focused attention on spilites and their associations.

scholarly journals Holocene sea-level change and estuary infill in North West Nelson, central New Zealand

The Holocene ◽  
2021 ◽  
pp. 095968362110604
Author(s):  
David M Kennedy ◽  
Beth V Risdon ◽  
Josephine LD Woods
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Central Basin ◽  
Marine Transgression ◽  
The Holocene ◽  
North West ◽  
Sedimentary Sequences ◽  
The North ◽  
History Of ◽  
Holocene Sea Level

The sedimentary sequences found within estuaries in the north west Nelson region of central New Zealand are investigated in order to quantify the timing of the end of the Post Glacial Marine Transgression. This region has been identified as being relatively stable in terms of vertical tectonic movement during the Holocene, but is yet to yield any reconstructions of eustatic sea level. In this study, we investigate the Holocene infill of a barrier estuary (Parapara Inlet) through sedimentological analysis and radiocarbon dating of 18 vibracores up to 4.2 m in length. It is found that the estuary infilled through a combination of lateral flood tide and fluvial delta progradation as well as vertical central basin infill. The central basin infilled at a consistent rate of 0.4 mm/year in both the mid (7.0–6.0 ka) and late-Holocene (2.5–1.5 ka). By the time of early human (Maori) settlement (c. 1 ka), the estuary surface was at low intertidal elevations with sediment being transported from the fluvial to tidal delta. A discernible change in sedimentation rates could not be associated with Maori settlement; however, infill rates increased to at least 12.5 mm/year in the past 150 years due hydraulic sluicing associated with mining. The sedimentary history of Parapara Inlet is compared to nearby Whanganui Inlet, d’Urville Island and Nelson to establish the character of regional Holocene sea level movement. It is found that relative sea level reached modern elevations between 8 and 7 ka in the region. The similarity between sea level curves for the end of the post glacial marine transgression (PMT) to other tectonically stable sites in northern New Zealand suggests that this curve can now be considered a true eustatic signal for the New Zealand archipelago.

scholarly journals SOILS OF NORTH AUCKLAND

1953 ◽  
pp. 25-38
Author(s):  
N.H. Taylor ◽  
C.F. Sutherland
Keyword(s):  
New Zealand ◽  
Main Axis ◽  
Geological Structures ◽  
North West ◽  
North East ◽  
The North

The topography of North Auckland is varied and somewhat intricate, as geological structures parallel with the north-west trend of the peninsula are broken across by structures trending north-east parallel with the main axis of New Zealand.

Images of Homelessness: The Home of the Needy Aged

2021 ◽  
Vol 10 ◽  
pp. 53-60
Author(s):  
Christine McCarthy
Keyword(s):  
New Zealand ◽  
Support Structures ◽  
Chronic Homelessness ◽  
West Side ◽  
North West ◽  
Architectural Support ◽  
The North ◽  
The Press ◽  
The Needy ◽  
House Fires

Homelessness in 1880s New Zealand, as reported in the press, appears to be more intimate and less melodramatic than overseas examples. House fires, such as that of William Beals' eight-roomed house in Epsom, the destruction by fire of Mr Keogh's seven-roomed dwelling on the north-west side of Mount Pukekaroro, and the 1884 fire which broke out "on the grounds of St. Mary's Orphanage, Ponsonby" are examples. Chronic homelessness, when it appears, occurs via the reporting of institutional and architectural support structures. The paper will examine a specific example of an architecture for the homeless: the Home for the Needy Aged in Newtown, Wellington.

The long-nosed fur seal (Arctocephalus forsteri) in South Australia in 2013–14: abundance, status and trends

2015 ◽  
Vol 63 (2) ◽  
pp. 101 ◽  
Author(s):  
P. D. Shaughnessy ◽  
S. D. Goldsworthy ◽  
A. I. Mackay
Keyword(s):  
New Zealand ◽  
South Australia ◽  
Australian Population ◽  
North West ◽  
The North ◽  
Fur Seals ◽  
Fur Seal ◽  
Increasing Trend ◽  
Small Sites ◽  
New Zealand Fur Seal

The long-nosed (or New Zealand) fur seal (Arctocephalus forsteri) breeds in southern Australia and New Zealand. Most of the Australian population is in South Australia, between Kangaroo Island and Eyre Peninsula. Fur seal populations in southern Australia were heavily exploited by colonial sealers between 1801 and 1830, resulting in major reductions. Numbers remained low for 150 years, then slowly built up and new colonies established across their presumed former range. Here we present estimates of pup abundance at South Australia colonies, mostly during the 2013–14 breeding season. Long-nosed fur seals bred from Baudin Rocks in the south-east to Fenelon Island in the north-west. In total, 29 breeding colonies produced 20 431 pups, 3.6 times greater than the 1989–90 estimate; the increase is attributed to recovery from 19th century overharvesting. The 2013–14 pup estimate leads to an estimate of abundance of long-nosed fur seals in South Australia of 97 200. Most pups were on Kangaroo Island (49.6%) and the Neptune Islands (38.6%). New breeding colonies were identified on Williams Island and at two small sites on Kangaroo Island. The increasing trend in South Australia is likely to continue over the coming decade, primarily by expansion in colonies on Kangaroo Island and by establishment of new colonies.

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