A catalogue of marine heatwave metrics and trends for the Australian region

Abstract This study investigates the role of large-scale environmental factors, notably sea surface temperature (SST), low-level relative vorticity, and deep-tropospheric vertical wind shear, in the interannual variability of November–April tropical cyclone (TC) activity in the Australian region. Extensive correlation analyses were carried out between TC frequency and intensity and the aforementioned large-scale parameters, using TC data for 1970–2006 from the official Australian TC dataset. Large correlations were found between the seasonal number of TCs and SST in the Niño-3.4 and Niño-4 regions. These correlations were greatest (−0.73) during August–October, immediately preceding the Australian TC season. The correlations remain almost unchanged for the July–September period and therefore can be viewed as potential seasonal predictors of the forthcoming TC season. In contrast, only weak correlations (<+0.37) were found with the local SST in the region north of Australia where many TCs originate; these were reduced almost to zero when the ENSO component of the SST was removed by partial correlation analysis. The annual frequency of TCs was found to be strongly correlated with 850-hPa relative vorticity and vertical shear of the zonal wind over the main genesis areas of the Australian region. Furthermore, correlations between the Niño SST and these two atmospheric parameters exhibited a strong link between the Australian region and the Niño-3.4 SST. A principal component analysis of the SST dataset revealed two main modes of Pacific Ocean SST variability that match very closely with the basinwide patterns of correlations between SST and TC frequencies. Finally, it is shown that the correlations can be increased markedly (e.g., from −0.73 to −0.80 for the August–October period) by a weighted combination of SST time series from weakly correlated regions.

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The Seasonal Cycle of Blocking and Associated Physical Mechanisms in the Australian Region and Relationship with Rainfall

Monthly Weather Review ◽

10.1175/mwr-d-13-00040.1 ◽

2013 ◽

Vol 141 (12) ◽

pp. 4534-4553 ◽

Cited By ~ 27

Author(s):

M. J. Pook ◽

J. S. Risbey ◽

P. C. McIntosh ◽

C. C. Ummenhofer ◽

A. G. Marshall ◽

...

Keyword(s):

Southern Ocean ◽

Seasonal Cycle ◽

Seasonal Temperature ◽

Ocean Fronts ◽

Temperature Changes ◽

Physical Mechanisms ◽

Australian Region ◽

Continental Antarctica ◽

Positive Correlations ◽

Blocking Index

Abstract The seasonal cycle of blocking in the Australian region is shown to be associated with major seasonal temperature changes over continental Antarctica (approximately 15°–35°C) and Australia (about 8°–17°C) and with minor changes over the surrounding oceans (below 5°C). These changes are superimposed on a favorable background state for blocking in the region resulting from a conjunction of physical influences. These include the geographical configuration and topography of the Australian and Antarctic continents and the positive west to east gradient of sea surface temperature in the Indo-Australian sector of the Southern Ocean. Blocking is represented by a blocking index (BI) developed by the Australian Bureau of Meteorology. The BI has a marked seasonal cycle that reflects seasonal changes in the strength of the westerly winds in the midtroposphere at selected latitudes. Significant correlations between the BI at Australian longitudes and rainfall have been demonstrated in southern and central Australia for the austral autumn, winter, and spring. Patchy positive correlations are evident in the south during summer but significant negative correlations are apparent in the central tropical north. By decomposing the rainfall into its contributions from identifiable synoptic types during the April–October growing season, it is shown that the high correlation between blocking and rainfall in southern Australia is explained by the component of rainfall associated with cutoff lows. These systems form the cyclonic components of blocking dipoles. In contrast, there is no significant correlation between the BI and rainfall from Southern Ocean fronts.

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Evaluating synoptic systems in the CMIP5 climate models over the Australian region

Climate Dynamics ◽

10.1007/s00382-015-2961-y ◽

2016 ◽

Vol 47 (7-8) ◽

pp. 2235-2251 ◽

Cited By ~ 17

Author(s):

Peter B. Gibson ◽

Petteri Uotila ◽

Sarah E. Perkins-Kirkpatrick ◽

Lisa V. Alexander ◽

Andrew J. Pitman

Keyword(s):

Climate Models ◽

Australian Region ◽

Cmip5 Climate Models

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Coastal winds drive a recruitment mechanism for estuarine fisheries

10.1101/2020.06.24.170068 ◽

2020 ◽

Author(s):

Hayden T. Schilling ◽

Charles Hinchliffe ◽

Jonathan P. Gillson ◽

Anthony Miskiewicz ◽

Iain M. Suthers

Keyword(s):

Larval Fish ◽

Future Research ◽

Larval Abundance ◽

Spawning Period ◽

Onshore Wind ◽

Larval Recruitment ◽

Australian Region ◽

Coastal Winds ◽

Key Driver ◽

Catch Rates

AbstractCoastal winds transport larval fish onshore or offshore which may contribute to estuarine recruitment, yet our understanding of the mechanism underlying this relationship is limited. Here, we show that larval abundance of coastally spawned species increased with weak to moderate upwelling favourable winds 14 days prior to sampling, reflecting increased nutrient and plankton availability for larval fish. A strong decline in larval abundance was observed following strong upwelling favourable winds while abundance increased with onshore (downwelling favourable) winds, in relation to offshore and onshore wind-driven transport. Subsequently, we show that effects of wind during the spawning period can be detected in lagged estuarine commercial fisheries catch rates of coastally spawned species (lagged by 2 – 8 years depending on species’ growth rates), representing the same mechanism proposed for larval fish. Upwelling favourable winds in the southeast Australian region have increased since 1850 while onshore winds have decreased, which may reduce larval recruitment to estuaries. Coastal winds are likely an important factor for estuarine recruitment in the east Australian region and future research on the estuarine recruitment of fish should incorporate coastal winds. As global winds are changing, it is important to investigate if this mechanism is applicable to other regions around the world where coastal winds are a key driver of upwelling.

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Seagrasses in the South-East Australian Region—Distribution, Metabolism, and Morphology in Response to Hydrodynamic, Substrate, and Water Quality Stressors

Seagrasses of Australia ◽

10.1007/978-3-319-71354-0_14 ◽

2018 ◽

pp. 419-444 ◽

Cited By ~ 1

Author(s):

Angus J. P. Ferguson ◽

Peter R. Scanes ◽

Jaimie D. Potts ◽

Matthew P. Adams ◽

Katherine R. O’Brien

Keyword(s):

Water Quality ◽

The South ◽

Australian Region

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