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1
Goler, Robert, Michael J. Reeder, Roger K. Smith, Harald Richter, Sarah Arnup, Tom Keenan, Peter May, and Jorg Hacker. "Low-Level Convergence Lines over Northeastern Australia. Part I: The North Australian Cloud Line." Monthly Weather Review 134, no. 11 (November 1, 2006): 3092–108. http://dx.doi.org/10.1175/mwr3239.1.
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Abstract Observations of dry-season north Australian cloud lines (NACLs) that form in the Gulf of Carpentaria region of northern Australia and the sea-breeze circulations that initiate them are described. The observations were made during the 2002 Gulf Lines Experiment (GLEX) and include measurements made by an instrumented research aircraft. The observations are compared with numerical simulations made from a two-dimensional cloud-scale model. Particular emphasis is placed on the interaction between the east coast and west coast sea breezes near the west coast of Cape York Peninsula. The sea breezes are highly asymmetric due to the low-level easterly synoptic flow over the peninsula. The west coast sea breeze is well defined with a sharp leading edge since the opposing flow limits its inland penetration, keeping it close to its source of cold air. In contrast, the east coast sea breeze is poorly defined since it is aided by the easterly flow and becomes highly modified by daytime convective mixing as it crosses over the peninsula. Both the observations and the numerical model show that, in the early morning hours, the mature NACL forms at the leading edge of a gravity current. The numerical model simulations show that this gravity current arises as a westward-moving land breeze from Cape York Peninsula. Convergence at the leading edge of this land breeze is accompanied by ascent, which when strong enough produces cloud. Observations show that the decay of the NACL is associated with a decline in the low-level convergence and a weakening of the ascent.
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Masouleh, Zahra Pazandeh, David John Walker, and John McCauley Crowther. "A Long-Term Study of Sea-Breeze Characteristics: A Case Study of the Coastal City of Adelaide." Journal of Applied Meteorology and Climatology 58, no. 2 (February 2019): 385–400. http://dx.doi.org/10.1175/jamc-d-17-0251.1.
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AbstractThe sea-breeze characteristics of the Adelaide, Australia, coastline have been studied by applying a sea-breeze detection algorithm to 3- and 6-hourly meteorological records of near-surface and upper-air data at Adelaide Airport from 1955 to 2007. The sea breeze is typically a westerly gulf breeze combined with a later-occurring southerly ocean breeze. Regression analysis showed a significant increasing trend in the intensity of sea breezes but not in their frequency. Over the 52-yr period, there was an average increase of 1 m s−1 in zonal and 0.7 m s−1 in meridional sea-breeze wind speed components. The annually and seasonally averaged maximum wind speeds on sea-breeze days increased significantly over the 52-yr period of the study by 0.65 m s−1 for the whole year, 0.48 m s−1 in spring, 1.02 m s−1 in summer, and 1.10 m s−1 in autumn. A comparison of hourly data for 1985–95 with those for 1996–2007 showed frequencies of sea-breeze onset times less than 4 h from sunrise increasing from 29% to 36%, durations greater than 8 h increasing from 51% to 59%, and times of maximum sea breeze between 2 and 6 h after sunrise increasing from 44% to 50%. The monthly frequency of sea breezes was found to increase by 2.8 percentage points for each degree Celsius rise in monthly average maximum air temperature at Adelaide Airport. The meridional ocean-breeze wind speed, unlike the gulf-breeze wind speed, is also correlated with maximum air temperature at Adelaide Airport.
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Gallop, Shari L., Cyprien Bosserelle, Charitha B. Pattiaratchi, Ian Eliot, and Ivan D. Haigh. "THE INFLUENCE OF CALCARENITE LIMESTONE REEFS ON BEACH EROSION AND RECOVERY, FROM SECONDS TO YEARS." Coastal Engineering Proceedings 1, no. 33 (October 18, 2012): 72. http://dx.doi.org/10.9753/icce.v33.sediment.72.
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Mechanisms through which natural rock and coral landforms interact with waves, currents, sediment transport and beach morphology are still poorly understood. Therefore, interactions between sediment transport and calcarenite limestone landforms at Yanchep Lagoon in southwestern Australia were investigated over a cascade of spatial and temporal scales: from single waves, through sea breeze and storm events, to seasonal and inter-annual variability. The hypotheses that were confirmed included: (1) hard landforms with higher elevations relative to sea level are more likely to reduce beach erosion but also to inhibit recovery; and (2) the placement and continuity of landforms in the nearshore can generate current jets, and hence local sediment sources and sinks. These hypotheses were consistently confirmed at all scales, however results show that to fully explain changes at broader scales (such as inter-annual and seasonal changes) an understanding at finer scales (such as during sea breezes, storm event and single waves) was necessary.
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Hing, Stephanie, Sue Foster, and Di Evans. "Animal Welfare Risks in Live Cattle Export from Australia to China by Sea." Animals 11, no. 10 (September 30, 2021): 2862. http://dx.doi.org/10.3390/ani11102862.
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There are long-standing and ongoing concerns about the welfare of animals in the Australian live export trade by sea. However, scrutiny of animal welfare on board vessels is generally hindered by a lack of independent reporting. Cattle voyages from Australia to China have concerned animal welfare advocates due to their long duration and lack of consistent veterinary oversight. In April 2018, following a media exposé of animal cruelty and declining public trust, the Australian government installed Independent Observers on some live export voyages. Summaries of Independent Observer (IO) reports by the Department of Agriculture and Water Resources (DAWR) provided a new and independent source of information about management of animals in the live export trade. The IO summaries on live cattle export voyages to China for the period July 2018 to December 2019 (n = 37) were reviewed. The IO summaries detailed voyages that carried 147,262 slaughter, feeder or breeder cattle which included both dairy and beef breeds. The long-haul voyages averaged 20 days in duration, generally departing the ports of Fremantle and Portland and discharging at ports in northern China. Key animal welfare risk factors identified in the IO summaries included: hunger, thirst, exposure to extreme temperatures, poor pen conditions, health issues, absence of veterinarians, rough seas, poor ship infrastructure, mechanical breakdown and mismanagement at discharge.
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Arnup, Sarah J., and Michael J. Reeder. "The Diurnal and Seasonal Variation of the Northern Australian Dryline." Monthly Weather Review 135, no. 8 (August 1, 2007): 2995–3008. http://dx.doi.org/10.1175/mwr3455.1.
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Abstract The diurnal and seasonal variations of the northern Australian dryline are examined by constructing climatologies of low-level dynamic and thermodynamic variables taken from the high-resolution Australian Bureau of Meteorology’s Limited Area Prediction Scheme (LAPS) forecasts from 2000 to 2003. The development of the dryline is analyzed within the framework of the frontogenesis function applied to the mixing ratio and the airstream diagnostics of Cohen and Schultz. A case study of 12–13 October 2002 illustrating the airmass boundaries over the Australian region is also examined. Daytime surface heating produces sea-breeze circulations around the coast and a large inland heat trough that extends east–west along northern Australia. At night, air parcels accelerate toward low pressure, increasing convergence and deformation within the heat trough. This sharpens the moisture gradient across the tropical and continental airmass boundary into a dryline. This is different than the dryline of the Great Plains in the United States, which generally weakens overnight. The Australian dryline is strongest in spring just poleward of the Gulf of Carpentaria, where the moisture gradient across the heat trough is enhanced by the coast, and the axis of dilatation is closely aligned with mixing ratio isopleths. The dryline is weakest in winter, when the heat trough is weak. The LAPS 3-h forecasts are in good agreement with observations obtained from the Automatic Weather Station network. The 3-h forecasts capture the observed diurnal and seasonal cycle of the airmass boundaries. However, the sea-breeze circulation and ageostrophic flow into the surface heat trough is limited by the model resolution. The LAPS 3-h forecasts may therefore underestimate the nocturnal intensification of the dryline, especially since the inland moisture content is overestimated.
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Short, Ewan. "Verifying Operational Forecasts of Land–Sea-Breeze and Boundary Layer Mixing Processes." Weather and Forecasting 35, no. 4 (August 1, 2020): 1427–45. http://dx.doi.org/10.1175/waf-d-19-0244.1.
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AbstractForecasters working for Australia’s Bureau of Meteorology (BoM) produce a 7-day forecast in two key steps: first they choose a model guidance dataset to base the forecast on, and then they use graphical software to manually edit these data. Two types of edits are commonly made to the wind fields that aim to improve how the influences of boundary layer mixing and land–sea-breeze processes are represented in the forecast. In this study the diurnally varying component of the BoM’s official wind forecast is compared with that of station observations and unedited model guidance datasets. Coastal locations across Australia over June, July, and August 2018 are considered, with data aggregated over three spatial scales. The edited forecast produces a lower mean absolute error than model guidance at the coarsest spatial scale (over 50 000 km2), and achieves lower seasonal biases over all spatial scales. However, the edited forecast only reduces errors or biases at particular times and locations, and rarely produces lower errors or biases than all model guidance products simultaneously. To better understand physical reasons for biases in the mean diurnal wind cycles, modified ellipses are fitted to the seasonally averaged diurnal wind temporal hodographs. Biases in the official forecast diurnal cycle vary with location for multiple reasons, including biases in the directions that sea breezes approach coastlines, amplitude biases, and disagreement in the relative contribution of sea-breeze and boundary layer mixing processes to the mean diurnal cycle.
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Rafiq, Syeda, Charitha Pattiaratchi, and Ivica Janeković. "Dynamics of the Land–Sea Breeze System and the Surface Current Response in South-West Australia." Journal of Marine Science and Engineering 8, no. 11 (November 17, 2020): 931. http://dx.doi.org/10.3390/jmse8110931.
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The land–sea breeze (LSB) system, driven by the thermal contrast between the land and the adjacent ocean is a widely known atmospheric phenomenon, which occurs in coastal regions globally. South-west Australia experiences a persistent and one of the strongest LSB systems globally with maximum wind speeds associated with the LSB system often exceeding 15 ms−1. In this paper, using field measurements and numerical simulations, we examine: (1) the local winds associated with the land–sea breeze with an emphasis on the ocean; and, (2) the response of the surface currents to the diurnal wind forcing. The measurements indicated that the wind speeds decreased between midnight and 0400 and increased rapidly after 1100, reaching maxima >10 ms−1 around 1800) associated with the sea breeze and decreased to midnight. Wind directions were such that they were blowing from south-east (120°) in the morning and changed to almost southerly (~200°) in the afternoon. Decomposition of the wind record to the diurnal and synoptic components indicated that the diurnal component of winds (i.e., LSB) was oriented along the south-west to north-east axis. However, the stronger synoptic winds were from the south-east to south quadrant and in combination with the LSB, the winds consisted of a strong southerly component. We examined the evolution, horizontal extent, and propagation properties of sea breeze fronts for characteristic LSB cycles and the sea breeze cell propagating offshore and inland. The results indicated that the sea breeze cell was initiated in the morning in a small area, close to 33° S, 115.5° E, with a width of ~25 km and expanded onshore, offshore and alongshore. The sea breeze cell expanded faster (30 kmh−1) and farther (120 km) in the offshore direction than in the onshore direction (10 kmh−1 and 30–40 km). Winds during the LSB cycle followed a counterclockwise rotation that was also reflected in the surface currents. The winds and surface currents rotated anticlockwise with the surface currents responding almost instantaneously to changes in wind forcing but were modified by topography. The diurnal surface currents were enhanced due to the resonance between the LSB forcing and the inertial response.
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Goler, Robert A. "Eastward-Propagating Undular Bores over Cape York Peninsula." Monthly Weather Review 137, no. 8 (August 1, 2009): 2632–45. http://dx.doi.org/10.1175/2009mwr2833.1.
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Abstract The existence of eastward-propagating bores over Cape York Peninsula is shown from data obtained during the Gulf Lines Experiment (GLEX) conducted during September and October 2002 and from numerical modeling experiments. The disturbances were detected regularly at two stations, observable on 24 days during the 40-day experiment. The passage of a typical disturbance exhibits a sudden increase in pressure of around 1 hPa, often accompanied by undulations, and a change in the wind speed and direction from an easterly to a westerly flow. Disturbances were not observed during days of strong easterly flow. A two-dimensional nonhydrostatic mesoscale model is used to examine the formation of these disturbances. It is shown that the west coast sea breeze is shallow and does not penetrate far inland because of the opposing low-level easterly flow. In contrast, the east coast sea breeze is deeper and is less stable because it is modified by daytime convective mixing as it crosses the peninsula. As the east coast sea breeze overrides the west coast sea breeze, the west coast sea breeze produces an eastward-propagating bore on the stable layer laid down by the east coast sea breeze. About 2 h after generation, the bore becomes undular. These eastward-propagating disturbances are shown to be associated with the westward-propagating north Australian cloud line and the northeasterly morning glory. In addition, it is shown here that an undular bore can be formed when cold-air downdrafts from afternoon deep convection enter the stable layer created by the east coast sea breeze. Four events from GLEX are believed to have been formed in this way. The eastward-propagating disturbances produced in this way are accompanied neither by the north Australian cloud line nor by the northeasterly morning glory.
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Soderholm, Joshua S., Hamish A. McGowan, Harald Richter, Kevin Walsh, Tony Wedd, and Tammy M. Weckwerth. "Diurnal Preconditioning of Subtropical Coastal Convective Storm Environments." Monthly Weather Review 145, no. 9 (September 2017): 3839–59. http://dx.doi.org/10.1175/mwr-d-16-0330.1.
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Boundary layer evolution in response to diurnal forcing is manifested at the mesobeta and smaller scales of the atmosphere. Because this variability resides on subsynoptic scales, the potential influence upon convective storm environments is often not captured in coarse observational and modeling datasets, particularly for complex physical settings such as coastal regions. A detailed observational analysis of diurnally forced preconditioning for convective storm environments of South East Queensland, Australia (SEQ), during the Coastal Convective Interactions Experiment (2013–15) is presented. The observations used include surface-based measurements, aerological soundings, and dual-polarization Doppler radar. The sea-breeze circulation was found to be the dominant influence; however, profile modification by the coastward advection of the continental boundary layer was found to be an essential mechanism for favorable preconditioning of deep convection. This includes 1) enhanced moisture in the city of Brisbane, potentiality due to an urban heat island–enhanced land–sea thermal contrast, 2) significant afternoon warming and moistening above the sea breeze resulting from the advection of the inland convective boundary layer coastward under prevailing westerly flow coupled with the sea-breeze return flow, and 3) substantial variations in near-surface moisture likely associated with topography and land use. For the 27 November 2014 Brisbane hailstorm, which caused damages exceeding $1.5 billion Australian dollars (AUD), the three introduced diurnal preconditioning processes are shown to favor a mesoscale convective environment supportive of large hailstone growth. The hybrid high-precipitation supercell storm mode noted for this event and previous similar events in SEQ is hypothesized to be more sensitive to variations in near-surface and boundary layer instability in contrast to contemporary supercell storms.
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Soderholm, Joshua, Hamish McGowan, Harald Richter, Kevin Walsh, Tammy Weckwerth, and Matthew Coleman. "The Coastal Convective Interactions Experiment (CCIE): Understanding the Role of Sea Breezes for Hailstorm Hotspots in Eastern Australia." Bulletin of the American Meteorological Society 97, no. 9 (September 1, 2016): 1687–98. http://dx.doi.org/10.1175/bams-d-14-00212.1.
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Abstract Thunderstorm-affected communities develop an awareness of “hotspot” regions that historically experience more frequent or intense storm activity across many years. A scientifically based understanding of this localized variability has significant implications for both the public and industry; however, a lack of sufficiently long and robust observational datasets has limited prior research at the mesogamma spatial scale (2–20 km). This is particularly true for coastal environments, where hotspot activity has been documented in very few locales (e.g., Florida, southern Appalachian coastal plains, and the Iberian Peninsula), despite 45% of the global population living within 150 km of the coast. The Coastal Convective Interactions Experiment (CCIE) focuses on quantifying hailstorm hotspot activity for the coastal South East Queensland (SEQ) region of Australia and understanding the meteorological conditions that result in the spatial clustering of hailstorm activity. An automated thunderstorm identification and tracking technique applied to 18 years of radar data identifies not only the hailstorm hotpots well known to experienced local forecasters but an apparent link between localized maxima and the presence of sea-breeze activity. These climatological findings provided the motivation and guidance for a two-season field campaign to investigate the role of the sea breeze in thunderstorm development. Details of the experiment strategy and equipment specifications are presented alongside preliminary results. Significant complexities were observed within sea-breeze and thunderstorms circulations, limiting the application of standard concepts for idealized gravity current interactions. Furthermore, a multi-instrument case study of a sea-breeze–thunderstorm cold pool interaction identifies the comparatively low sea-breeze buoyancy as the primary contributor toward inhibiting new convective initiation, despite the vorticity balance argument favoring deeper updrafts.
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Gunson, Jim, and Graham Symonds. "Spectral Evolution of Nearshore Wave Energy during a Sea-Breeze Cycle." Journal of Physical Oceanography 44, no. 12 (November 26, 2014): 3195–208. http://dx.doi.org/10.1175/jpo-d-13-0205.1.
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Abstract From in situ measurements taken over several sea-breeze cycles off a beach in southwest (SW) Australia, the evolution of the one-dimensional spectrum of wave energy is observed to have a distinctive spectral shape. During the land-breeze phase of the cycle, lower rates of dissipation of wave energy are seen at high frequencies compared to midrange frequencies above the remnant wind-sea peak. A simulation of waves was performed using the Simulating Waves Nearshore (SWAN) model and produced the same spectral evolution, by generating longshore modes, as seen in the observations. The performance of whitecapping schemes available in SWAN was assessed, and the Alves–Banner scheme was found to best simulate the observed growth and decay of the wave spectra. During the onshore phase of the sea-breeze cycle, local wave growth is duration limited, and during the offshore land-breeze phase, wave growth is fetch limited. From an examination of the modeled two-dimensional spectra it is found that quadruplet interactions play a key role in spreading high-frequency wave energy in frequency and direction space.
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Bates, Amy L., Shawn R. McGrath, Maxwell B. Allworth, Susan M. Robertson, and Gordon Refshauge. "A Cross-Sectional Study of Commercial Ewe Management Practices for Different Sheep Breeds across Southern Australia." Animals 13, no. 3 (January 23, 2023): 388. http://dx.doi.org/10.3390/ani13030388.
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The management of ewes across southern Australia may vary with breed and can change over time and, as such, a greater understanding of producer management practices and the motivations that influence these practices is required. A cross-sectional study was performed by telephone interview with sheep producers managing Composite, Maternal, Merino or shedding ewe breeds mated in either spring, summer, or autumn. The surveyed producers were a unique subset of southern Australian producers. A large proportion of the surveyed producers followed current best practice guidelines for ewe mating and lambing nutritional management; however, some producers did not align with these targets. Further, some producers did not see the value in attaining the current recommendations. Pregnancy scanning was widely practiced, likely an artefact of the recruitment process; however, a few producers did not utilize this information for nutritional management at lambing time. Finally, most producers were active in their search for new information, seeking information regularly from a wide range of sources and reported making management changes within the last five years. Further work is required to understand why some producers are not adopting best practice where possible and to understand current barriers for adoption. Management guidelines for all sheep breeds are required to best manage sheep across southern Australia.
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Kostomakhin, N. M., and M. S. Mansurova. "Economically useful traits of cows Australian breeding in the Amur region." Glavnyj zootehnik (Head of Animal Breeding), no. 2 (February 1, 2021): 3–10. http://dx.doi.org/10.33920/sel-03-2102-01.
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Recently, a signifi cant number of livestock of specialized beef breeds is imported from abroad particularly from Australia. So the study of the adaptive ability and eff ectiveness of the use of Australian cattle of Hereford breed in the Amur region is relevant. The purpose of the work was to study the growth, development and reproductive capacity of Hereford cattle in the Amur region. Experimental studies have been carried out in the collective farm “Tomichevsky” in the Belogorsky district in the Amur region for four years. The reproductive ability of imported Hereford cows of Australian selection, as well as indicators of calving easy, live weight and height in the rump have been examined in the article. The assessment of similar indicators of progeny obtained from imported cows-dams and dams of local selection have been given. It has been found that the cows of the Australian breeding had a large live weight and were taller than the cows of Hereford breed the same age as the cows of Amur breeding. Fewer off spring were obtained from imported cows, a high percentage of dead calves were born, long open day’s period and calving interval, and a low coeffi cient of reproductive ability have been revealed. When analyzing the results of the study of the adaptive ability of Hereford cows obtained from imported Australian Hereford cows and Hereford cows of the Amur breeding, it has been found that all calving were successful in the cows, and no cases of dead calves were born. Indicators of reproductive ability were within the normal range, but were more optimal in the progeny of Australian breeding. The results obtained on base of researches we can conclude that the progeny of Australian Herefords have higher adaptive abilities in comparison with similar indicators of their mothers.
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Firestone, K. "Australian Mammals: Biology and Captive Management. Jackson S., A Review by Karen Firestone." Australian Mammalogy 27, no. 1 (2005): 103. http://dx.doi.org/10.1071/am05103_br.
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MY first impressions when I saw this book was ?what a remarkable achievement? and ?I want one for my library?. The author of this book, Stephen Jackson, hails from a long association with the zoo industry having worked for many years at Taronga Zoo and Healesville Sanctuary and more recently with the Animal Welfare Unit of the NSW Department of Primary Industries, so he comes with a commanding knowledge of the requirements for captive management of Australian mammals. He has spent considerable time formulating this volume; it is nicely presented, thorough in scope and clearly very authoritative. However, while expert information does not come cheap, the price of this book (are you sitting down?) at $240 puts it well out of the price range of many. I?m still gasping. This book is marketed for (generally underpaid) zookeepers, veterinarians, zoologists, researchers and students, but this price restricts it to being a specialist reference volume purchased by a limited number of users, zoological institutions, and university libraries with good acquisitions budgets. This is unfortunate as every wildlife carer, zoo, and breeding facility (in Australia and elsewhere) that holds or breeds Australian mammals should have one of these volumes. It would be fantastic to see a complete series of these ?Biology and Captive Management? books: Australian Birds: Biology and Captive Management, Australian reptiles..., Australian insects... etc.
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Tory, K. J., M. E. Cope, G. D. Hess, S. Lee, K. Puri, P. C. Manins, and N. Wong. "The Australian Air Quality Forecasting System. Part III: Case Study of a Melbourne 4-Day Photochemical Smog Event." Journal of Applied Meteorology 43, no. 5 (May 1, 2004): 680–95. http://dx.doi.org/10.1175/2092.1.
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Abstract A 4-day photochemical smog event in the Melbourne, Victoria, Australia, region (6–9 March 2001) is examined to assess the performance of the Australian Air Quality Forecasting System (AAQFS). Although peak ozone concentrations measured during this period did not exceed the 1-h national air quality standard of 100 ppb, elevated maximum ozone concentrations in the range of 50–80 ppb were recorded at a number of monitoring stations on all four days. These maximum values were in general very well forecast by the AAQFS. On all but the third day the system predicted the advection of ozone precursors over Port Phillip (the adjacent bay) during the morning, where, later in the day, relatively high ozone concentrations developed. The ozone was advected back inland by bay and sea breezes. On the third day, a southerly component to the background wind direction prevented the precursor drainage over the bay, and the characteristic ozone cycle was disrupted. The success of the system's ability to predict peak ozone at individual monitoring stations was largely dependent on the direction and penetration of the sea and bay breezes, which in turn were dependent on the delicate balance between these winds and the opposing synoptic flow.
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Collins, Teresa, Jordan Hampton, and Anne Barnes. "A Systematic Review of Heat Load in Australian Livestock Transported by Sea." Animals 8, no. 10 (September 27, 2018): 164. http://dx.doi.org/10.3390/ani8100164.
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The transport of animals by sea (‘live export’) is one of the most important current animal welfare issues in Australian society. Recent media attention has highlighted concerns regarding the effects of high environmental temperature and humidity on the welfare and mortality of sheep being shipped live from Australia to the Middle East, especially during the Northern Hemisphere summer. To improve understanding of how and why harmful heat load occurs, we systematically reviewed Australian research into heat load and sea transport. High thermal load occurs during the sea transport of sheep and cattle from Australia when animals are subject to hot and humid environmental conditions and cannot remove heat generated by metabolic processes in the body, potentially also gaining heat from the environment. Several approaches have been proposed to mitigate these risks, including avoidance of voyages in hot seasons, selection of heat-resistant livestock breeds, reducing stocking density, and improved ventilation. We identified a lack of scientific literature relating to heat load in animals transported by sea and considerable potential for bias in the literature that was found. We identified the following priority research areas: (i) experimental manipulation of variables thought to influence the incidence and severity of harmful heat load, including sheep density; (ii) further assessment of the Heat Stress Risk Assessment (HSRA) model used to predict heat load events, and (iii) development of a suite of animal welfare indicators that may allow identification of ‘at risk’ sheep before they reach debilitating heat load condition. Addressing these knowledge gaps will assist efforts to reduce the frequency and intensity of harmful heat load events.
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Pattiaratchi, Charitha, Bruce Hegge, John Gould, and Ian Eliot. "Impact of sea-breeze activity on nearshore and foreshore processes in southwestern Australia." Continental Shelf Research 17, no. 13 (November 1997): 1539–60. http://dx.doi.org/10.1016/s0278-4343(97)00016-2.
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Rennie, Susan J., Robert D. McCauley, and Charitha B. Pattiaratchi. "Thermal structure above the Perth Canyon reveals Leeuwin Current, Undercurrent and weather influences and the potential for upwelling." Marine and Freshwater Research 57, no. 8 (2006): 849. http://dx.doi.org/10.1071/mf05247.
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The Perth Canyon is a focal feeding area for pygmy blue whales on the Western Australian coast. Studies aimed at elaborating oceanographic mechanisms within the canyon were conducted between 2002 and 2005. Strings of temperature loggers set around the canyon rim were used to examine the water column’s response to climatological forcing, current meanders, upwelling and downwelling. Six moorings were positioned on a plateau in 500 m of water on the northern canyon rim, and one was positioned at the canyon head. Loggers were positioned to sample the whole water column, including the Leeuwin Current and Undercurrent. Moorings revealed spatial temperature differences between the plateau and canyon head. Observed temperature features ranged temporally from seasonal to <1 day. Seasonal changes in water temperature agreed with published Leeuwin Current studies: for example, mixed layer and stratification changes were apparent. Other observed temperature changes were related to Leeuwin Current movement and wind forcing such as the summer sea breeze and winter storms. Storms induced mixing, re-stratification, downwelling and upwelling as the wind changed direction and strength. Changes lasting a day were associated with diurnal sea breezes, internal waves and possibly solitary waves. Bottom loggers indicated that upwelling and downwelling events each occurred up to 20% of the time.
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Oliphant, A. J., A. P. Sturman, and N. J. Tapper. "The evolution and structure of a tropical island sea/land-breeze system, northern Australia." Meteorology and Atmospheric Physics 78, no. 1-2 (September 1, 2001): 45–59. http://dx.doi.org/10.1007/s007030170005.
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Contardo, Stephanie, Graham Symonds, Laura Segura, Ryan Lowe, and Jeff Hansen. "Infragravity Wave Energy Partitioning in the Surf Zone in Response to Wind-Sea and Swell Forcing." Journal of Marine Science and Engineering 7, no. 11 (October 28, 2019): 383. http://dx.doi.org/10.3390/jmse7110383.
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An alongshore array of pressure sensors and a cross-shore array of current velocity and pressure sensors were deployed on a barred beach in southwestern Australia to estimate the relative response of edge waves and leaky waves to variable incident wind wave conditions. The strong sea breeze cycle at the study site (wind speeds frequently > 10 m s−1) produced diurnal variations in the peak frequency of the incident waves, with wind sea conditions (periods 2 to 8 s) dominating during the peak of the sea breeze and swell (periods 8 to 20 s) dominating during times of low wind. We observed that edge wave modes and their frequency distribution varied with the frequency of the short-wave forcing (swell or wind-sea) and edge waves were more energetic than leaky waves for the duration of the 10-day experiment. While the total infragravity energy in the surf zone was higher during swell forcing, edge waves were more energetic during wind-sea periods. However, low-frequency (0.005–0.023 Hz) edge waves were found to be dominant in absence of wind-sea conditions, while higher-frequency (0.023–0.050 Hz) edge waves dominated when wind-sea conditions were present.
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Höller, H., H. D. Betz, K. Schmidt, R. V. Calheiros, P. May, E. Houngninou, and G. Scialom. "Lightning characteristics observed by a VLF/LF lightning detection network (LINET) in Brazil, Australia, Africa and Germany." Atmospheric Chemistry and Physics Discussions 9, no. 2 (March 6, 2009): 6061–146. http://dx.doi.org/10.5194/acpd-9-6061-2009.
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Abstract. This paper describes lightning characteristics as obtained in four sets of lightning measurements during recent field campaigns in different parts of the world from mid-latitudes to the tropics by the novel VLF/LF (very low frequency/low frequency) lightning detection network (LINET). The paper gives a general overview on the approach, and a synopsis of the statistical results for the observation periods as a whole and for one special day in each region. The focus is on the characteristics of lightning which can specifically be observed by this system like intra-cloud and cloud-to-ground stroke statistics, vertical distributions of intra-cloud strokes or peak current distributions. Some conclusions regarding lightning produced NOx are also presented as this was one of the aims of the tropical field campaigns TROCCINOX (Tropical Convection, Cirrus and Nitrogen Oxides Experiment) and TroCCiBras (Tropical Convection and Cirrus Experiment Brazil) in Brazil during January/February 2005, SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere) and TWP-ICE (Tropical Warm Pool – International Cloud Experiment) during November/December 2005 and January/February 2006, respectively, in the Darwin area in N-Australia, and of AMMA (African Monsoon Multidisciplinary Analyses) in W-Africa during June–November 2006. Regional and temporal characteristics of lightning are found to be dependent on orographic effects (e.g. S-Germany, Brazil, Benin), land-sea breeze circulations (N-Australia) and especially the evolution of the monsoons (Benin, N-Australia). Large intra-seasonal variability in lightning occurrence was found for the Australian monsoon between the strong convection during build-up and break phases and the weak wet monsoon phase with only minor lightning activity. Total daily lightning rates can be of comparable intensity in all regions with the heaviest events found in Germany and N-Australia. The frequency of occurrence of such days was by far the largest in N-Australia. In accordance with radar observed storm structures, the intra-cloud stroke mean emission heights were found distinctly different in Germany (8 km) as compared to the tropics (up to 12 km in N-Australia). The fraction of intra-cloud strokes (compared to all strokes) was found to be relatively high in Brazil and Australia (0.83 and 0.74, respectively) as compared to Benin and Germany (0.67 and 0.69, respectively). Using stroke peak currents and vertical location information, lightning NOx (LNOx) production under defined standard conditions can be compared for the different areas of observation. LNOx production per standard stroke was found to be most efficient for the N-Australian and S-German thunderstorms whereas the yield from Brazilian and W-African strokes was nearly 40% less. On the other hand, the main NO contribution in Brazil was from intra-cloud (IC) strokes whereas in Benin it was due to cloud-to-ground (CG) components. For the German and Australian strokes both stroke types contributed similar amounts to the total NO outcome.
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Höller, H., H. D. Betz, K. Schmidt, R. V. Calheiros, P. May, E. Houngninou, and G. Scialom. "Lightning characteristics observed by a VLF/LF lightning detection network (LINET) in Brazil, Australia, Africa and Germany." Atmospheric Chemistry and Physics 9, no. 20 (October 20, 2009): 7795–824. http://dx.doi.org/10.5194/acp-9-7795-2009.
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Abstract. This paper describes lightning characteristics as obtained in four sets of lightning measurements during recent field campaigns in different parts of the world from mid-latitudes to the tropics by the novel VLF/LF (very low frequency/low frequency) lightning detection network (LINET). The paper gives a general overview on the approach, and a synopsis of the statistical results for the observation periods as a whole and for one special day in each region. The focus is on the characteristics of lightning which can specifically be observed by this system like intra-cloud and cloud-to-ground stroke statistics, vertical distributions of intra-cloud strokes or peak current distributions. Some conclusions regarding lightning produced NOx are also presented as this was one of the aims of the tropical field campaigns TROCCINOX (Tropical Convection, Cirrus and Nitrogen Oxides Experiment) and TroCCiBras (Tropical Convection and Cirrus Experiment Brazil) in Brazil during January/February 2005, SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere) and TWP-ICE (Tropical Warm Pool-International Cloud Experiment) during November/December 2005 and January/February 2006, respectively, in the Darwin area in N-Australia, and of AMMA (African Monsoon Multidisciplinary Analyses) in W-Africa during June–November 2006. Regional and temporal characteristics of lightning are found to be dependent on orographic effects (e.g. S-Germany, Brazil, Benin), land-sea breeze circulations (N-Australia) and especially the evolution of the monsoons (Benin, N-Australia). Large intra-seasonal variability in lightning occurrence was found for the Australian monsoon between the strong convection during build-up and break phases and the weak active monsoon phase with only minor lightning activity. Total daily lightning stroke rates can be of comparable intensity in all regions with the heaviest events found in Germany and N-Australia. The frequency of occurrence of such days was by far the largest in N-Australia. In accordance with radar observed storm structures, the intra-cloud stroke mean emission heights were found distinctly different in Germany (8 km) as compared to the tropics (up to 12 km in N-Australia). The fraction of intra-cloud strokes (compared to all strokes) was found to be relatively high in Brazil and Australia (0.83 and 0.82, respectively) as compared to Benin and Germany (0.64 and 0.69, respectively). Using stroke peak currents and vertical location information, lightning NOx (LNOx) production under defined standard conditions can be compared for the different areas of observation. LNOx production per standard stroke was found to be most efficient for the N-Australian and S-German thunderstorms whereas the yield from Brazilian and W-African strokes was nearly 40% less. On the other hand, the main NO contribution in Brazil was from intra-cloud (IC) strokes whereas in Benin it was due to cloud-to-ground (CG) components. For the German and Australian strokes both stroke types contributed similar amounts to the total NO outcome.
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Abbs, Deborah J. "Sea-Breeze Interactions along a Concave Coastline in Southern Australia: Observations and Numerical Modeling Study." Monthly Weather Review 114, no. 5 (May 1986): 831–48. http://dx.doi.org/10.1175/1520-0493(1986)114<0831:sbiaac>2.0.co;2.
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Dominick, Doreena, Stephen R. Wilson, Clare Paton-Walsh, Ruhi Humphries, Élise-Andrée Guérette, Melita Keywood, Paul Selleck, Dagmar Kubistin, and Ben Marwick. "Particle Formation in a Complex Environment." Atmosphere 10, no. 5 (May 14, 2019): 275. http://dx.doi.org/10.3390/atmos10050275.
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A field aerosol measurement campaign as part of the Measurements of Urban, Marine and Biogenic Air (MUMBA) campaign was conducted between 16 January 2013 and 15 February 2013 in the coastal city of Wollongong, Australia. The objectives of this research were to study the occurrence frequency, characteristics and factors that influence new particle formation processes. Particle formation and growth events were observed from particle number size distribution data in the range of 14 nm–660 nm measured using a scanning particle mobility sizer (SMPS). Four weak Class I particle formation and growth event days were observed, which is equivalent to 13% of the total observation days. The events occurred during the day, starting after 8:30 Australian Eastern Standard time with an average duration of five hours. The events also appeared to be positively linked to the prevailing easterly to north easterly sea breezes that carry pollutants from sources in and around Sydney. This suggests that photochemical reactions and a combination of oceanic and anthropogenic air masses are among the factors that influenced these events.
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Mihanović, Hrvoje, Charitha Pattiaratchi, and Florence Verspecht. "Diurnal Sea Breezes Force Near-Inertial Waves along Rottnest Continental Shelf, Southwestern Australia." Journal of Physical Oceanography 46, no. 11 (November 2016): 3487–508. http://dx.doi.org/10.1175/jpo-d-16-0022.1.
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AbstractObservations of upper-ocean dynamics close to the critical latitude (ratio of the local inertial to diurnal frequency is 0.94) from a range of platforms (surface currents using HF radar, moored instruments, and satellite remote sensing data) off southwest Australia indicated the presence of energetic, near-inertial waves generated through the diurnal–inertial resonance. During the austral summer, when southerly winds and land–sea breeze (LSB) system dominated the wind regime, strong counterclockwise diurnal motions (amplitudes surpassing 0.3 m s−1) penetrated to 300-m depth with diurnal vertical isotherm fluctuations up to 60 m. The upward phase propagation speed of ~140 m day−1, deep penetration of diurnal currents below the mixed layer, and the ~180° phase difference between the upper and lower water column suggested that the local LSB system caused the resonant diurnal motions. Relative vorticity fluctuations along two cross-shore transects indicated changes to the local effective Coriolis frequency by more than 50% (±0.5f). In the presence of strong and relatively consistent cross-shore diurnal wind forcing in the study area, the main factors that controlled the observed energetic but sporadic near-inertial oscillations were the Leeuwin Current strength and spatial–temporal variations. These variations controlled the effective Coriolis frequency and enabled the effective pumping of diurnal wind energy into the ocean particularly when the effective Coriolis frequency was ~24 h.
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Gallop, Shari L., Florence Verspecht, and Charitha B. Pattiaratchi. "Sea breezes drive currents on the inner continental shelf off southwest Western Australia." Ocean Dynamics 62, no. 4 (February 2, 2012): 569–83. http://dx.doi.org/10.1007/s10236-011-0515-3.
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KULIKOVA, A. YA. "QUALITY OF SHEEP SEED OF MEAT-WOOL BREEDS BY SEASON YEAR." Sheep, goats, wool business, no. 4 (2022): 20–22. http://dx.doi.org/10.26897/2074-0840-2022-4-20-22.
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In the conditions of the hot climate of the South of Russia, purebred Texel sheep of Australian breeding by the beginning of the main breeding season in sheep breeding in the North Caucasus zone (end of August, fi rst decade of September) have reduced sexual activity, ejaculate volume and unsatisfactory seed quality, compared with Texel sheep of Finnish breeding and Kuban Lincolns. The reproductive ability of texel sheep of Australian breeding is restored at a later date.
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Hess, G. D., K. J. Tory, M. E. Cope, S. Lee, K. Puri, P. C. Manins, and M. Young. "The Australian Air Quality Forecasting System. Part II: Case Study of a Sydney 7-Day Photochemical Smog Event." Journal of Applied Meteorology 43, no. 5 (May 1, 2004): 663–79. http://dx.doi.org/10.1175/2094.1.
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Abstract The performance of the Australian Air Quality Forecasting System (AAQFS) is examined by means of a case study of a 7-day photochemical smog event in the Sydney region. This was the worst smog event for the 2000/ 01 oxidant season, and, because of its prolonged nature, it provided the opportunity to demonstrate the ability of AAQFS to forecast situations involving recirculation of precursors and remnant ozone, fumigation, and complex meteorological dynamics. The forecasting system was able to successfully predict high values of ozone, although at times the peak concentrations for the inland stations were underestimated. The dynamics for the Sydney region require a sensitive balance between the synoptic and mesoscale flows. Often high concentrations of ozone were advected inland by the sea breeze. On two occasions the system forecast a synoptic flow that was too strong, which blocked the inland advancement of the sea breeze. The peak ozone forecasts were underpredicted at the inland stations on those occasions. An examination of possible factors causing forecast errors has indicated that the AAQFS is more sensitive to errors in the meteorological conditions, rather than in the emissions or chemical mechanism in the Sydney region.
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Zhou, Yifei, Huade Guan, Saeedeh Gharib, Okke Batelaan, and Craig T. Simmons. "Cooling power of sea breezes and its inland penetration in dry-summer Adelaide, Australia." Atmospheric Research 250 (March 2021): 105409. http://dx.doi.org/10.1016/j.atmosres.2020.105409.
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Forbes, Lawrence K., and Shaun R. Belward. "Atmospheric solitary waves: some applications to the morning glory of the Gulf of Carpentaria." Journal of Fluid Mechanics 321 (August 25, 1996): 137–55. http://dx.doi.org/10.1017/s0022112096007677.
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A mathematical model is proposed to describe atmospheric solitary waves at the interface between a ‘shallow’ layer of fluid near the ground and a stationary upper layer of compressible air. The lower layer is in motion relative to the ground, perhaps as a result of a distant thunderstorm or a sea breeze, and possesses constant vorticity. The upper fluid is compressible and isothermal, so that its density and pressure both decrease exponentially with height. The profile and speed of the solitary wave are determined, for a wave of given amplitude, using a boundary-integral method. Results are discussed in relation to the ‘morning glory’, which is a remarkable meteorological phenomenon evident in the far north of Australia.
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Hurley, P. J., and P. C. Manins. "Meteorological Modeling on High-Ozone Days in Perth, Western Australia." Journal of Applied Meteorology 34, no. 7 (July 1, 1995): 1643–52. http://dx.doi.org/10.1175/1520-0450-34.7.1643.
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Abstract The West Australian capital city of Perth is located on a coastal plain between the sea to the west and an escarpment rising to the east. It is isolated from all other cities or sources of pollution. In this study, the meteorological conditions leading to high ozone levels have been classified according to the dominant weather patterns using both synoptic charts and air monitoring data. The data revealed that practically all high-ozone days were associated with recirculation of ozone or its precursors. Meteorological modeling was then performed for the generic conditions leading to high ozone in the Perth region. The modeling predicted that recirculation of surface air over the Perth region was common. Both same-day and next-day recirculation of surface air are features of the model predictions and are conducive to high ozone levels. The modeling predicts day-by-day buildup of smog to be a favored occurrence under these synoptic conditions. Other interesting meteorological features seen in Perth observations on high-ozone days were also predicted by the modeling, including stalling sea breezes under some conditions, hydraulic jump effects over the escarpment, and mesoscale enhancement of the west coast trough.
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Skinner, T., and N. Tapper. "Preliminary sea breeze studies over Bathurst and Melville Islands, northern Australia, as part of the island thunderstorm experiment (ITEX)." Meteorology and Atmospheric Physics 53, no. 1-2 (1994): 77–94. http://dx.doi.org/10.1007/bf01031906.
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Kala, J., T. J. Lyons, D. J. Abbs, and U. S. Nair. "Numerical Simulations of the Impacts of Land-Cover Change on a Southern Sea Breeze in South-West Western Australia." Boundary-Layer Meteorology 135, no. 3 (March 20, 2010): 485–503. http://dx.doi.org/10.1007/s10546-010-9486-z.
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Pazandeh Masouleh, Zahra, David John Walker, and John McCauley Crowther. "Sea breeze characteristics on two sides of a shallow gulf: study of the Gulf St Vincent in South Australia." Meteorological Applications 23, no. 2 (March 3, 2016): 222–29. http://dx.doi.org/10.1002/met.1547.
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Guérette, Élise-Andrée, Clare Paton-Walsh, Ian Galbally, Suzie Molloy, Sarah Lawson, Dagmar Kubistin, Rebecca Buchholz, et al. "Composition of Clean Marine Air and Biogenic Influences on VOCs during the MUMBA Campaign." Atmosphere 10, no. 7 (July 10, 2019): 383. http://dx.doi.org/10.3390/atmos10070383.
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Volatile organic compounds (VOCs) are important precursors to the formation of ozone and fine particulate matter, the two pollutants of most concern in Sydney, Australia. Despite this importance, there are very few published measurements of ambient VOC concentrations in Australia. In this paper, we present mole fractions of several important VOCs measured during the campaign known as MUMBA (Measurements of Urban, Marine and Biogenic Air) in the Australian city of Wollongong (34°S). We particularly focus on measurements made during periods when clean marine air impacted the measurement site and on VOCs of biogenic origin. Typical unpolluted marine air mole fractions during austral summer 2012-2013 at latitude 34°S were established for CO2 (391.0 ± 0.6 ppm), CH4 (1760.1 ± 0.4 ppb), N2O (325.04 ± 0.08 ppb), CO (52.4 ± 1.7 ppb), O3 (20.5 ± 1.1 ppb), acetaldehyde (190 ± 40 ppt), acetone (260 ± 30 ppt), dimethyl sulphide (50 ± 10 ppt), benzene (20 ± 10 ppt), toluene (30 ± 20 ppt), C8H10 aromatics (23 ± 6 ppt) and C9H12 aromatics (36 ± 7 ppt). The MUMBA site was frequently influenced by VOCs of biogenic origin from a nearby strip of forested parkland to the east due to the dominant north-easterly afternoon sea breeze. VOCs from the more distant densely forested escarpment to the west also impacted the site, especially during two days of extreme heat and strong westerly winds. The relative amounts of different biogenic VOCs observed for these two biomes differed, with much larger increases of isoprene than of monoterpenes or methanol during the hot westerly winds from the escarpment than with cooler winds from the east. However, whether this was due to different vegetation types or was solely the result of the extreme temperatures is not entirely clear. We conclude that the clean marine air and biogenic signatures measured during the MUMBA campaign provide useful information about the typical abundance of several key VOCs and can be used to constrain chemical transport model simulations of the atmosphere in this poorly sampled region of the world.
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Lemm, A. J., B. J. Hegge, and G. Masselink. "Offshore wave climate, Perth (Western Australia), 1994 - 96." Marine and Freshwater Research 50, no. 2 (1999): 95. http://dx.doi.org/10.1071/mf98081.
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The offshore wave climate of Perth (Western Australia) was analysed by using 2.5 years of non-directional 20-min wave data collected from March 1994 to August 1996. The mean wave conditions are characterized by a significant wave height (Hs) of 2.0 m and a spectral mean wave period (Tm) of 8.8 s. However, considerable annual variation in the wave conditions is experienced because of a distinct seasonality in the regional wind regime. During summer, daily sea breezes generate moderate seas (ambient Hs 1 to 2 m; Tm <8 s). During winter, frequent storms associated with mid-latitude depressions generate heavy seas and swell (ambient Hs 1.5 to 2.5 m; Tm >8 s). A low-amplitude background swell (Hs ~0.5 m), generated distantly in the Indian and Southern Oceans, is present all year round. Analysis of extreme wave conditions (Hs >4 m) indicates that, on average, 30 storms are experienced annually, and the storms are most frequent and intense during July. Estimates of extreme Hs, based on all available offshore wave data (12 years, 1975–96), for 1- and 100-year return periods, are 6.7 m and 9.8 m, respectively.
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He, Bao-Jie, Lan Ding, and Deo Prasad. "Outdoor thermal environment of an open space under sea breeze: A mobile experience in a coastal city of Sydney, Australia." Urban Climate 31 (March 2020): 100567. http://dx.doi.org/10.1016/j.uclim.2019.100567.
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Shen, Lixing, Chuanfeng Zhao, Xingchuan Yang, Yikun Yang, and Ping Zhou. "Observed slump of sea land breeze in Brisbane under the effect of aerosols from remote transport during 2019 Australian mega fire events." Atmospheric Chemistry and Physics 22, no. 1 (January 12, 2022): 419–39. http://dx.doi.org/10.5194/acp-22-419-2022.
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Abstract. The 2019 Australian mega fires were unprecedented considering their intensity and consistency. There has been much research on the environmental and ecological effects of these mega fires, most of which focused on the effect of huge aerosol loadings and the ecological devastation. Sea land breeze (SLB) is a regional thermodynamic circulation closely related to coastal pollution dispersion, yet few have looked into how it is influenced by different types of aerosols transported from either nearby or remote areas. Mega fires provide an optimal scenario of large aerosol emissions. Near the coastal site of Brisbane Archerfield during January 2020, when mega fires were the strongest, reanalysis data from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) showed that mega fires did release huge amounts of aerosols, making aerosol optical depth (AOD) of total aerosols, black carbon (BC) and organic carbon (OC) approximately 240 %, 425 % and 630 % of the averages in other non-fire years. Using 20 years' wind observations of hourly time resolution from a global observation network managed by the National Oceanic and Atmospheric Administration (NOAA), we found that the SLB day number during that month was only 4, accounting for 33.3 % of the multi-years' average. The land wind (LW) speed and sea wind (SW) speed also decreased by 22.3 % and 14.8 % compared with their averages respectively. Surprisingly, fire spot and fire radiative power (FRP) analysis showed that heating effects and aerosol emission of the nearby fire spots were not the main causes of the local SLB anomaly, while the remote transport of aerosols from the fire centre was mainly responsible for the decrease of SW, which was partially offset by the heating effect of nearby fire spots and the warming effect of long-range transported BC and CO2. The large-scale cooling effect of aerosols on sea surface temperature (SST) and the burst of BC contributed to the slump of LW. The remote transport of total aerosols was mainly caused by free diffusion, while the large-scale wind field played a secondary role at 500 m. The large-scale wind field played a more important role in aerosol transport at 3 km than at 500 m, especially for the gathered smoke, but free diffusion remained the major contributor. The decrease of SLB speed boosted the local accumulation of aerosols, thus making SLB speed decrease further, forming a positive feedback mechanism.
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Yenneti, Komali, Lan Ding, Deo Prasad, Giulia Ulpiani, Riccardo Paolini, Shamila Haddad, and Mattheos Santamouris. "Urban Overheating and Cooling Potential in Australia: An Evidence-Based Review." Climate 8, no. 11 (November 4, 2020): 126. http://dx.doi.org/10.3390/cli8110126.
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Cities in Australia are experiencing unprecedented levels of urban overheating, which has caused a significant impact on the country’s socioeconomic environment. This article provides a comprehensive review on urban overheating, its impact on health, energy, economy, and the heat mitigation potential of a series of strategies in Australia. Existing studies show that the average urban heat island (UHI) intensity ranges from 1.0 °C to 13.0 °C. The magnitude of urban overheating phenomenon in Australia is determined by a combination of UHI effects and dualistic atmospheric circulation systems (cool sea breeze and hot desert winds). The strong relation between multiple characteristics contribute to dramatic fluctuations and high spatiotemporal variabilities in urban overheating. In addition, urban overheating contributes to serious impacts on human health, energy costs, thermal comfort, labour productivity, and social behaviour. Evidence suggest that cool materials, green roofs, vertical gardens, urban greenery, and water-based technologies can significantly alleviate the UHI effect, cool the ambient air, and create thermally balanced cities. Urban greenery, especially trees, has a high potential for mitigation. Trees and hedges can reduce the average maximum UHI by 1.0 °C. The average maximum mitigation performance values of green roofs and green walls are 0.2 °C and 0.1 °C, respectively. Reflective roofs and pavements can reduce the average maximum UHI by 0.3 °C. In dry areas, water has a high cooling potential. The average maximum cooling potential using only one technology is 0.4 °C. When two or more technologies are used at the same time, the average maximum UHI drop is 1.5 °C. The mitigation strategies identified in this article can help the governments and other stakeholders manage urban heating in the natural and built environment, and save health, energy, and economic costs.
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Jackson, Robert C., Scott M. Collis, Valentin Louf, Alain Protat, and Leon Majewski. "A 17 year climatology of the macrophysical properties of convection in Darwin." Atmospheric Chemistry and Physics 18, no. 23 (December 13, 2018): 17687–704. http://dx.doi.org/10.5194/acp-18-17687-2018.
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Abstract. The validation of convective processes in global climate models (GCMs) could benefit from the use of large datasets that provide long-term climatologies of the spatial statistics of convection. To that regard, echo top heights (ETHs), convective areas, and frequencies of mesoscale convective systems (MCSs) from 17 years of data from a C-band polarization (CPOL) radar are analyzed in varying phases of the Madden–Julian Oscillation (MJO) and northern Australian monsoon in order to provide ample validation statistics for GCM validation. The ETHs calculated using velocity texture and reflectivity provide similar results, showing that the ETHs are insensitive to various techniques that can be used. Retrieved ETHs are correlated with those from cloud top heights retrieved by Multifunctional Transport Satellites (MTSATs), showing that the ETHs capture the relative variability in cloud top heights over seasonal scales. Bimodal distributions of ETH, likely attributable to the cumulus congestus clouds and mature stages of convection, are more commonly observed when the active phase of the MJO is over Australia due to greater mid-level moisture during the active phase of the MJO. The presence of a convectively stable layer at around 5 km altitude over Darwin inhibiting convection past this level can explain the position of the modes at around 2–4 km and 7–9 km. Larger cells were observed during break conditions compared to monsoon conditions, but only during the inactive phase of the MJO. The spatial distributions show that Hector, a deep convective system that occurs almost daily during the wet season over the Tiwi Islands, and sea-breeze convergence lines are likely more common in break conditions. Oceanic MCSs are more common during the night over Darwin. Convective areas were generally smaller and MCSs more frequent during active monsoon conditions. In general, the MJO is a greater control on the ETHs in the deep convective mode observed over Darwin, with higher distributions of ETH when the MJO is active over Darwin.
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Gentile, Sabrina, Rossella Ferretti, and Frank Silvio Marzano. "Investigating Hector Convective Development and Microphysical Structure Using High-Resolution Model Simulations, Ground-Based Radar Data, and TRMM Satellite Data." Journal of the Atmospheric Sciences 71, no. 4 (March 27, 2014): 1353–70. http://dx.doi.org/10.1175/jas-d-13-0107.1.
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Abstract One event of a tropical thunderstorm typically observed in northern Australia, known as Hector, is investigated using high-resolution model output from the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) observations from a ground-based weather radar located in Berrimah (Australia) and data from the Tropical Rainfall Measuring Mission (TRMM) satellite. The analysis is carried out by tracking the full life cycle of Hector from prestorm stage to the decaying stage. In both the prestorm stage, characterized by nonprecipitating cells, and the triggering stage, when the Hector storm is effectively initiated, an analysis is performed with the aid of high-spatial-and-temporal-resolution MM5 output and the Berrimah ground-based radar imagery. During the mature (“old”) stage of Hector, considering the conceptual model for tropical convection suggested by R. Houze, TRMM Microwave Imager satellite-based data were added to ground-based radar data to analyze the storm vertical structure (dynamics, thermodynamics, and hydrometeor contents). Model evaluation with respect to observations (radar reflectivity and TRMM data) suggests that MM5 performed fairly well in reproducing the dynamics of Hector, providing support to the assertion that the strength of convection, in terms of vertical velocity, largely contributes to the vertical distribution of hydrometeors. Moreover, the stages of the storm and its vertical structure display good agreement with Houze’s aforementioned conceptual model. Finally, it was found that the most important triggering mechanisms for this Hector event are topography, the sea breeze, and a gust front produced by previous convection.
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Mejía, J. F., and L. Morawska. "An investigation of nucleation events in a coastal urban environment in the Southern Hemisphere." Atmospheric Chemistry and Physics Discussions 9, no. 1 (January 23, 2009): 2195–222. http://dx.doi.org/10.5194/acpd-9-2195-2009.
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Abstract. The occurrence of and conditions favourable to nucleation were investigated at an industrial and commercial coastal location in Brisbane, Australia during five different campaigns covering a total period of 13 months. To identify potential nucleation events, the difference in number concentration in the size range 14–30 nm (N14−30) between consecutive observations was calculated using first-order differencing. The data showed that nucleation events were a rare occurrence, and that in the absence of nucleation the particle number was dominated by particles in the range 30–300 nm. In many instances, total particle concentration declined during nucleation. There was no clear pattern in change in NO and NO2 concentrations during the events. SO2 concentration, in the majority of cases, declined during nucleation but there were exceptions. Most events took place in summer, followed by winter and then spring, and no events were observed for the autumn campaigns. The events were associated with sea breeze and long-range transport. Roadside emissions, in contrast, did not contribute to nucleation, probably due to the predominance of particles in the range 50–100 nm associated with these emissions.
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Ranasinghe, Roshanka, and Charitha Pattiaratchi. "Circulation and mixing characteristics of a seasonally open tidal inlet: a field study." Marine and Freshwater Research 50, no. 4 (1999): 281. http://dx.doi.org/10.1071/mf98037.
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Tidal inlets in microtidal, wave-dominated coastal environments tend to close to the ocean seasonally. This obstructs navigation and could cause degradation of water quality in the estuary/lagoon connected to the inlet. Hence, engineering solutions are often implemented to prevent inlet closure. However, a prior knowledge of circulation and mixing processes within the estuary is crucial for the sustainability of any engineering solution. This paper attempts to provide insight into circulation and mixing characteristics of seasonally open estuaries based on the results of a field study undertaken at Wilson Inlet, a typical seasonally open estuary, in south-western Australia. Results of the study indicate that this type of estuary may have two distinct behavioural patterns, in winter and in summer. During winter, solar heating causes density stratification during daytime, and convective cooling causes overnight de-stratification; a horizontal cyclonic gyre is established during winter by the combined action of the Coriolis force and streamflow. During summer, strong sea breezes (~10 m s–1 ) cause vertical mixing during daytime, and convective cooling vertically mixes the water column at night. When the inlet is open, sea water propagates into the estuary during flooding tides unless streamflows are very high.
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Robinson, N. H., J. D. Allan, J. A. Trembath, P. D. Rosenberg, G. Allen, and H. Coe. "The lofting of Western Pacific regional aerosol by island thermodynamics as observed around Borneo." Atmospheric Chemistry and Physics Discussions 12, no. 1 (January 12, 2012): 1215–65. http://dx.doi.org/10.5194/acpd-12-1215-2012.
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Abstract. Vertical profiles of aerosol chemical composition, number concentration and size were measured throughout the lower troposphere of Borneo, a large tropical island in the western Pacific Ocean. Aerosol composition, size and number concentration measurements (using an Aerodyne Aerosol Mass Spectrometer, Passive Cavity Aerosol Spectrometer Probe and Condensation Particle Counter, respectively) were made both upwind and downwind of Borneo, as well as over the island itself, on board the UK BAe-146 research aircraft as part of the OP3 project. Two meteorological regimes were identified – one dominated by isolated terrestrial convection (ITC) which peaked in the afternoon, and the other characterised by more regionally active mesoscale convective systems (MCS). Upwind profiles show aerosol to be confined to a shallow marine boundary layer below 930 ± 10 hPa (~760 m above sea level, a.s.l.). As this air mass advects over the island with the mean free troposphere synoptic flow during the ITC-dominated regime, it is convectively lofted above the terrestrial surface mixed layer to heights of between 945 ± 22 (~630 m a.s.l.) and 740 ± 44 hPa (~2740 m a.s.l.), consistent with a coupling between the synoptic steering level flow and island sea breeze circulations. Terrestrial aerosol was observed to be lofted into this higher layer through both moist convective uplift and transport through turbulent diurnal sea-breeze cells. At the peak of convective activity in the mid-afternoons, organic aerosol loadings in the lofted layer were observed to be substantially higher than in the morning (by a mean factor of three). This organic matter is dominated by secondary aerosol from processing of biogenic gas phase precursors. Aerosol number concentration profiles suggest formation of new particles aloft in the atmosphere. By the time the air mass reaches the west coast of the island, terrestrial aerosol is enhanced in the lofted layer. Such uplift of aerosol in Borneo is expected to increase aerosol lifetimes in the lower free troposphere downwind, as they are above the boundary layer and therefore less likely to be lost by wet or dry deposition. It is also likely to change the role they play in the semi-direct and direct aerosol effects. The long chain of islands extending from Malaysia to Australia may all similarly be expected to present an orographic barrier to low level mean flow. This would lead to significant transport of aerosol into the tropical free troposphere across the Western Pacific region.
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Robinson, N. H., J. D. Allan, J. A. Trembath, P. D. Rosenberg, G. Allen, and H. Coe. "The lofting of Western Pacific regional aerosol by island thermodynamics as observed around Borneo." Atmospheric Chemistry and Physics 12, no. 13 (July 12, 2012): 5963–83. http://dx.doi.org/10.5194/acp-12-5963-2012.
Full textAbstract:
Abstract. Vertical profiles of aerosol chemical composition, number concentration and size were measured throughout the lower troposphere of Borneo, a large tropical island in the western Pacific Ocean. Aerosol composition, size and number concentration measurements (using an Aerodyne Aerosol Mass Spectrometer, Passive Cavity Aerosol Spectrometer Probe and Condensation Particle Counter, respectively) were made both upwind and downwind of Borneo, as well as over the island itself, on board the UK BAe-146 research aircraft as part of the OP3 project. Two meteorological regimes were identified – one dominated by isolated terrestrial convection (ITC) which peaked in the afternoon, and the other characterised by more regionally active mesoscale convective systems (MCS). Upwind profiles show aerosol to be confined to a shallow marine boundary layer below 930 ± 10 hPa (~760 m above sea level, a.s.l.). As this air mass advects over the island with the mean free troposphere synoptic flow during the ITC-dominated regime, it is convectively lofted above the terrestrial surface mixed layer to heights of between 945 ± 22 (~630 m a.s.l.) and 740 ± 44 hPa (~2740 m a.s.l.), consistent with a coupling between the synoptic steering level flow and island sea breeze circulations. Terrestrial aerosol was observed to be lofted into this higher layer through both moist convective uplift and transport through turbulent diurnal sea-breeze cells. At the peak of convective activity in the mid-afternoons, organic aerosol loadings in the lofted layer were observed to be substantially higher than in the morning (by a mean factor of three). This organic matter is dominated by secondary aerosol from processing of biogenic gas phase precursors. Aerosol number concentration profiles suggest formation of new particles aloft in the atmosphere. By the time the air mass reaches the west coast of the island, terrestrial aerosol is enhanced in the lofted layer. Such uplift of aerosol in Borneo is expected to increase aerosol lifetimes in the lower free troposphere downwind, as they are above the boundary layer and therefore less likely to be lost by wet or dry deposition. It is also likely to change the role they play in the semi-direct and direct aerosol effects. The long chain of islands extending from Malaysia to Australia may all similarly be expected to present an orographic barrier to low level mean flow. This would lead to significant transport of aerosol into the tropical free troposphere across the Western Pacific region.
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Storey, Michael Anthony, and Owen F. Price. "Prediction of air quality in Sydney, Australia as a function of forest fire load and weather using Bayesian statistics." PLOS ONE 17, no. 8 (August 24, 2022): e0272774. http://dx.doi.org/10.1371/journal.pone.0272774.
Full textAbstract:
Smoke from Hazard Reduction Burns (HRBs) and wildfires contains pollutants that are harmful to human health. This includes particulate matter less than 2.5 μm in diameter (PM2.5), which affects human cardiovascular and respiratory systems and can lead to increased hospitalisations and premature deaths. Better models are needed to predict PM2.5 levels associated with HRBs so that agencies can properly assess smoke pollution risk and balance smoke risk with the wildfire mitigation benefits of HRBs. Given this need, our aim was to develop a probabilistic model of daily PM2.5 using Bayesian regression. We focused on the region around Sydney, Australia, which regularly has hazard reduction burning, wildfires and associated smoke. We developed two regional models (mean daily and maximum daily) from observed PM2.5, weather reanalysis and satellite fire hotspot data. The models predict that the worst PM2.5 in Sydney occurs when PM2.5 was high the previous day, there is low ventilation index (i.e. the product of wind speed and planetary boundary layer height), low temperature, west to northwest winds in the Blue Mountains, an afternoon sea breeze and large areas of HRBs are being conducted, particularly to the west and north of Sydney. A major benefit of our approach is that models are fast to run, require simple inputs and Bayesian predictions convey both predicted PM2.5 and associated prediction uncertainty. Future research could include the application of similar methods to other regions, collecting more data to improve model precision and developing Bayesian PM2.5 models for wildfires.
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Peace, Mika, Trent Mattner, Graham Mills, Jeffrey Kepert, and Lachlan McCaw. "Fire-Modified Meteorology in a Coupled Fire–Atmosphere Model." Journal of Applied Meteorology and Climatology 54, no. 3 (March 2015): 704–20. http://dx.doi.org/10.1175/jamc-d-14-0063.1.
Full textAbstract:
AbstractThe coupled fire–atmosphere model consisting of the Weather and Forecasting (WRF) Model coupled with the fire-spread model (SFIRE) module has been used to simulate a bushfire at D’Estrees Bay on Kangaroo Island, South Australia, in December 2007. Initial conditions for the simulations were provided by two global analyses: the GFS operational analysis and ERA-Interim. For each NWP initialization, the simulations were run with and without feedback from the fire to the atmospheric model. The focus of this study was examining how the energy fluxes from the simulated fire modified the local meteorological environment. With feedback enabled, the propagation speed of the sea-breeze frontal line was faster and vertical motion in the frontal zone was enhanced. For one of the initial conditions with feedback on, a vortex developed adjacent to the head fire and remained present for over 5 h of simulation time. The vortex was not present without fire–atmosphere feedback. The results show that the energy fluxes released by a fire can effect significant changes on the surrounding mesoscale atmosphere. This has implications for the appropriate use of weather parameters extracted from NWP and used in prediction for fire operations. These meteorological modifications also have implications for anticipating likely fire behavior.
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Zhou, Yong, Yi Liu, Jiandong Qiao, Mingjie Lv, Zhitao Du, Zhiqiang Fan, Jiaqi Zhao, et al. "Investigation on Global Distribution of the Atmospheric Trapping Layer by Using Radio Occultation Dataset." Remote Sensing 13, no. 19 (September 25, 2021): 3839. http://dx.doi.org/10.3390/rs13193839.
Full textAbstract:
The trapping layer refers to the atmospheric layer with vertical gradient of atmospheric refractivity less than −157 N-Units/km or vertical gradient of atmospheric modified refractivity 0 M-unit/km, which has a significant impact on radar and radio communication systems. Based on COSMIC and other radio occultation data, we show the statistical characteristics of the global trapping layer during 2005–2020.The statistical results show that the occurrence rate of the trapping layers is mainly concentrated between 50°S and 50°N, and higher occurrences of the trapping layers with more than 50% mainly occur in the boundary area between ocean and land, such as the northwest coastal area of Mexico, the west coastal area of Africa, the Mediterranean Sea, the Red Sea and the Arabian Sea, and the northwest area of Australia, etc. The altitude of the trapping layer is lower near the land and increases with the distance away from the coastline. The intensity is mainly between 6 M-unit and 24 M-unit (an M-unit is the unit of atmospheric modified refractivity), and the average value in some regions is above 24 M-unit, such as in the Arabian Sea area. In addition, the thickness of the trapping layer is between 50 and 240 m, and is generally larger over the ocean than over the land. These results reveal that the generation of the trapping layer is the result of the interaction of various background environmental factors such as radiation band migration, trade winds, monsoons, solar radiation heating, sea–land breezes and so on.
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Hamilton, L. J. "Methods to obtain representative surface wave spectra, illustrated for two ports of north-western Australia." Marine and Freshwater Research 48, no. 1 (1997): 43. http://dx.doi.org/10.1071/mf94220.
Full textAbstract:
Simple automatic methods of classifying surface wave spectra in terms of spectral shape are outlined and are used to examine the monthly wave climatology for the port approaches to Dampier and Port Hedland on the North West Shelf of Australia. Waves and swell at these shallow sites occur independently in three frequency bands. These correspond to low-energy long-period swell from distant sources (periods of 12 to 20 s), cyclones or energetic local storms (periods of 8 to 12 s), and local winds (periods of 4 to 8 s). Summer cyclones generate highest waves, but sea breezes are the dominant mode of wave generation. Waves and swell tend to occur episodically and independently in any month, and the peak frequency shifts during the wave generation process, so that a representative spectrum formed by simple averaging of spectra would be grossly oversmoothed. To overcome this, the monthly climatology is presented in terms of reference spectral shapes (the Ochi and Hubble 1976 North Atlantic formulations) that are most likely to occur for particular frequency bands and ranges of significant wave height. Measured spectra may then be selected as representative spectra from groupings associated with the most likely reference shapes, with further criteria such as spectral width being used to define what is typical. In some cases, the reference spectra provide good enough fits to enable them to be used directly as representative spectra.
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Gero, A. F., and A. J. Pitman. "The Impact of Land Cover Change on a Simulated Storm Event in the Sydney Basin." Journal of Applied Meteorology and Climatology 45, no. 2 (February 1, 2006): 283–300. http://dx.doi.org/10.1175/jam2337.1.
Full textAbstract:
Abstract The Regional Atmospheric Modeling System (RAMS) was run at a 1-km grid spacing over the Sydney basin in Australia to assess the impact of land cover change on a simulated storm event. The simulated storm used NCEP–NCAR reanalysis data, first with natural (i.e., pre-European settlement in 1788) land cover and then with satellite-derived land cover representing Sydney's current land use pattern. An intense convective storm develops in the model in close proximity to Sydney's dense urban central business district under current land cover. The storm is absent under natural land cover conditions. A detailed investigation of why the change in land cover generates a storm was performed using factorial analysis, which revealed the storm to be sensitive to the presence of agricultural land in the southwest of the domain. This area interacts with the sea breeze and affects the horizontal divergence and moisture convergence—the triggering mechanisms of the storm. The existence of the storm over the dense urban area of Sydney is therefore coincidental. The results herein support efforts to develop parameterization of urban surfaces in high-resolution simulations of Sydney's meteorological environment but also highlight the need to improve the parameterization of other types of land cover change at the periphery of the urban area, given that these types dominate the explanation of the results.