The Bureau of Meteorology

Melbourne, Australia

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Melbourne, Australia
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Dutta D.,CSIRO | Vaze J.,CSIRO | Kim S.,CSIRO | Hughes J.,CSIRO | And 3 more authors.
Journal of Hydrology | Year: 2017

Existing global and continental scale river models, mainly designed for integrating with global climate models, are of very coarse spatial resolutions and lack many important hydrological processes, such as overbank flow, irrigation diversion, groundwater seepage/recharge, which operate at a much finer resolution. Thus, these models are not suitable for producing water accounts, which have become increasingly important for water resources planning and management at regional and national scales. A continental scale river system model called Australian Water Resource Assessment River System model (AWRA-R) has been developed and implemented for national water accounting in Australia using a node-link architecture. The model includes major hydrological processes, anthropogenic water utilisation and storage routing that influence the streamflow in both regulated and unregulated river systems. Two key components of the model are an irrigation model to compute water diversion for irrigation use and associated fluxes and stores and a storage-based floodplain inundation model to compute overbank flow from river to floodplain and associated floodplain fluxes and stores. The results in the Murray-Darling Basin shows highly satisfactory performance of the model with median daily Nash-Sutcliffe Efficiency (NSE) of 0.64 and median annual bias of less than 1% for the period of calibration (1970–1991) and median daily NSE of 0.69 and median annual bias of 12% for validation period (1992–2014). The results have demonstrated that the performance of the model is less satisfactory when the key processes such as overbank flow, groundwater seepage and irrigation diversion are switched off. The AWRA-R model, which has been operationalised by the Australian Bureau of Meteorology for continental scale water accounting, has contributed to improvements in the national water account by substantially reducing accounted different volume (gain/loss). © 2017 Elsevier B.V.


Kabir M.A.,The Bureau of Meteorology | Kabir M.A.,Monash University | Dutta D.,CSIRO | Dutta D.,Monash University | Hironaka S.,NEWJEC Inc.
Water Resources Management | Year: 2014

The paper presents a process-based distributed modelling approach for estimating sediment budget at a river basin scale with partitions of suspended and bed loads by simulating sediment loads and their interactions. In this approach, a river basin is represented by hillslopes and a network of channels. Hillslopes are divided into an array of homogeneous grid cells for modelling surface runoff and suspended sediments. Channels are defined by incorporating flow hydraulic properties into the respective hillslope grids as sub-grid attributes for modelling both suspended and bed loads. Suspended sediment transport is modelled using one dimensional kinematic wave approximation of Saint-Venant's principles of conservation of mass and momentum. Transport capacity of runoff or streamflow is used to set the limit of suspended sediment transport rate. Bed load in channels is estimated based on the instantaneous water and hydraulic parameters. Fractional interchange between suspended load and bed load is then back calculated. The performance of the model was evaluated through a case study application in a large river basin in Japan. The model satisfactorily calculated the sediment transport and total sediment budget in the basin. The simulated bed load was found to be reasonable and consistent with the water flow and suspended sediment flux. The results showed the bed load can be expressed as a linear function of the suspended load. The fractions of different sediment loads also exhibit linear relationships with water discharge for the rising and recession limbs of the flood hydrographs. The case study has demonstrated that the process-based distributed modelling approach can efficiently describe the basin-scale sediment budgets with due consideration of the suspended and bed loads and their interactions in the hillslopes and channels. © 2014 Springer Science+Business Media Dordrecht.


Ying K.,CAS Institute of Atmospheric Physics | Zheng X.,CAS Institute of Atmospheric Physics | Zhao T.,CAS Institute of Atmospheric Physics | Frederiksen C.S.,The Bureau of Meteorology | And 2 more authors.
Climate Dynamics | Year: 2016

The patterns of interannual variability that arise from the slow (potentially predictable) and fast or intraseasonal (unpredictable) components of seasonal mean precipitation over eastern China are examined, based on observations from a network of 106 stations for the period 1951–2004. The analysis is done by using a variance decomposition method that allows identification of the sources of the predictability and the prediction uncertainty, from March–April–May (MAM) to September–October–November (SON). The average potential predictability (ratio of slow-to-total variance) of eastern China precipitation is generally moderate, with the highest value of 0.18 in June–July–August (JJA) and lowest value of 0.12 in April–May–June (AMJ). The leading predictable precipitation mode is significantly related to one-season-lead SST anomalies in the area of the Kuroshio Current during AMJ-to-JJA, the Indian-western Pacific SST in July–August–September (JAS), and the eastern tropical Pacific SST in MAM and SON. The prolonged linear trends, which are seen in the principal component time series associated with the second or third predictable precipitation modes in MJJ-to-ASO, also serve as a source of predictability for seasonal precipitation over eastern China. The predictive characteristics of the atmospheric circulation–precipitation relationship indicate that the western Pacific subtropical high plays a key role in eastern China precipitation. In addition, teleconnection patterns that are significantly related to the predictable precipitation component are also identified. The leading/second unpredictable precipitation modes from MAM to SON all show a monopole/dipole structure, which are accompanied by wavy circulation patterns that are related to intraseasonal events. © 2016 Springer-Verlag Berlin Heidelberg


Kabir M.A.,The Bureau of Meteorology | Dutta D.,CSIRO | Hironaka S.,NEWJEC Inc.
Water Resources Management | Year: 2014

Most process-based sediment dynamic models are based on the concept of sediment transport capacity (TC) of flow. Relationships between sediment TC and its characterized variables are found to vary widely, depending on the characteristics of a watershed and the underlying hydrological processes. This study has aimed to incorporate various widely used sediment transport capacity equations (TCEs) in a process-based sediment dynamic model, and to evaluate their relative performances in estimating suspended sediment dynamics at a river basin scale. The paper describes the modelling approaches and their application to a case study area (Abukuma River Basin, Japan), and then elaborates various parameters used in different TCEs with their useful impacts on modelling outcomes. The results of the case study have demonstrated that some of the TCEs are not suitable for simulating basin scale sediment dynamics. The TCEs that consist of more hydraulic parameters representing the flow and sediment transport processes have produced better outcomes. © 2014, Springer Science+Business Media Dordrecht.


Kabir M.A.,The Bureau of Meteorology | Dutta D.,CSIRO | Hironaka S.,NEWJEC Inc.
Water Resources Management | Year: 2014

The paper presents a process-based distributed modelling approach for estimating sediment budget at a river basin scale with partitions of suspended and bed loads by simulating sediment loads and their interactions. In this approach, a river basin is represented by hillslopes and a network of channels. Hillslopes are divided into an array of homogeneous grid cells for modelling surface runoff and suspended sediments. Channels are defined by incorporating flow hydraulic properties into the respective hillslope grids as sub-grid attributes for modelling both suspended and bed loads. Suspended sediment transport is modelled using one dimensional kinematic wave approximation of Saint-Venant’s principles of conservation of mass and momentum. Transport capacity of runoff or streamflow is used to set the limit of suspended sediment transport rate. Bed load in channels is estimated based on the instantaneous water and hydraulic parameters. Fractional interchange between suspended load and bed load is then back calculated. The performance of the model was evaluated through a case study application in a large river basin in Japan. The model satisfactorily calculated the sediment transport and total sediment budget in the basin. The simulated bed load was found to be reasonable and consistent with the water flow and suspended sediment flux. The results showed the bed load can be expressed as a linear function of the suspended load. The fractions of different sediment loads also exhibit linear relationships with water discharge for the rising and recession limbs of the flood hydrographs. The case study has demonstrated that the process-based distributed modelling approach can efficiently describe the basin-scale sediment budgets with due consideration of the suspended and bed loads and their interactions in the hillslopes and channels. © Springer Science+Business Media Dordrecht 2014.


News Article | August 9, 2016
Site: www.theguardian.com

Across Australia, climate science denialists are beside themselves with glee at the voting into office of one of their own. Late last week, the Australian Electoral Commission confirmed that Pauline Hanson’s One Nation party had snagged Queensland’s final 12th Senate spot. Her candidate, Malcolm Roberts, is now a senator. Roberts’ election is yet another demonstration of the quirkiness of Australia’s electoral system. Only 77 people actually voted for Roberts as a first preference but, thanks to the popularity of Hanson, he’s in for three years. Roberts’ own brand of climate denial – a heady mix of conspiracy theories and blind spots the size of the Antarctic ice sheet – is now in the national spotlight. Roberts has had wall-to-wall coverage across Australia’s media – from Sky News, to Lateline, to Insiders to flagship ABC radio. Even Triple J has joined in. News Corp’s Andrew Bolt, a strong promoter of the kind of material produced by Roberts, told the senator there were now “five or six out and proud voices of climate scepticism in the Senate”. So how did Roberts respond to his newfound fame? Well, he didn’t disappoint, telling every mainstream audience there was “no empirical evidence to show that carbon dioxide affects the climate in any way”. I’ve written several stories over the years about Roberts and the Galileo Movement – the climate science denial group founded in 2011 with radio personality Alan “climate change is witchcraft” Jones as its patron. Three years ago I pointed out how One Nation was taking its cues on climate science from Roberts. Last month I suggested that, if elected, Roberts would bring an extreme form of climate science denial to the Senate. But for those paying close attention to climate science denial – such as the string of US senators who spent hours talking about it only last month – Roberts sounds like a broken record. In Roberts’ case, the needle has been stuck for about six years. What about his conspiracy theories (he says they’re not conspiracies, just facts) that climate change is a scam pushed by global banks looking for cash and the UN on the hunt for global domination? Roberts didn’t disappoint there either. On ABC Melbourne, host Rafael Epstein asked Roberts: “Do you think the UN’s trying to impose some sort of global government through climate change policy?” For years, Roberts has been writing to politicians, government agencies, universities and scientists making the same claim that there is “no empirical evidence” to show fossil fuel burning causes climate change. You can go and read all that material on his website – I’ll see you in six months once you’ve read it all. So what does Roberts mean by “empirical evidence”? According to him, decisions should be based on “observations in the real world … it’s measured, real world data” and nothing else counts. There are two very obvious problems with Roberts’ argument. The “real world data” is sending a clear message that the Earth is gaining heat at a rapid rate and that this is a long-term trend. Whether you look at global air temperatures measured in the real world by thermometers or derived from satellites, or the temperature of the oceans at multiple depths, or the increasing frequency of extreme temperatures, or the rising sea levels, the melting ice sheets, the disappearing Arctic sea ice, the increasing risk of bushfires … we could go on and on with a parade of “empirical evidence”. At the same time, humans are adding CO2 to the atmosphere and oceans at a rate that groups like the Geological Society say are unprecedented “even in comparison with the massive injections of carbon to the atmosphere at the Palaeocene-Eocene boundary, which led to a major thermal event 55m years ago”. Roberts’ argument that science is only about “empirical evidence” might sound all sciencey to his interviewees and the lay audience. But it’s bunk. If all you rely on is “empirical evidence”, and reject modelling and analysis that uses that data, then you basically throw out large swathes of modern scientific endeavours. Prof Steven Sherwood, director of the Climate Change Research Centre at the University of New South Wales, told me: Roberts has built a whole suite of well-rehearsed arguments to enable him to reject any assertions put to him. They go like this, and I’m paraphrasing here. Climate scientists only say it’s warming because if they didn’t their grants would dry up. The Bureau of Meteorology and CSIRO have corrupted climate science and are thus guilty of corruption. Government agencies are politicised, which means anything they produce cannot be trusted. You can’t trust climate models, so anything that comes from them should be chucked out. One of Australia’s most famous and celebrated scientists is Prof Peter Doherty, who, in 1996, was jointly awarded a Nobel prize for his research into the immune system. Doherty told me he had sent Roberts “plenty of reports and material” but Roberts had ignored it. So Doherty has first-hand experience with Roberts and also knows a bit about the scientific method. He told me: So how should journalists react when a newly-minted senator makes claims that run against science academies across the planet while suggesting institutions and governments the world over – from the US military to the UN – are either part of, or have been hoodwinked by, a conspiracy that only he can and a few other people on the internet are able to see? According to Doherty “you have to respect the institutions of our democracy, including the Australian Senate, but that does not mean you have to respect the viewpoints held by individual senators”. So there is another approach journalists could take. In 2013, Roberts sent one of his voluminous reports to Ben Cubby, then the environment editor at the Sydney Morning Herald. I’ll leave you with Cubby’s response.


The BOM has not denied the breach but has stated that: The Bureau's systems are fully operational and the Bureau continues to provide reliable, ongoing access to high quality weather, climate, water and oceans information to its stakeholders. Unfortunately, little is known about what computers were hacked, nor what was actually done by the hackers. This in turn makes it hard to say definitively what will need to be done to clean up after the hack and more importantly, stop it happening again. What could realistically have been hacked? The Bureau of Meteorology, like any government agency, will have a network of desktop computers and servers that are used for their day-to-day business. These systems are the easiest targets because access can be obtained by "phishing" for user names and passwords directly from employees. This hacking approach was used by Chinese hackers in their infiltration of the New York Times in 2013. It is possible, but less likely, that the hackers were also able to access the BOM's latest supercomputer, a A$77 million Cray computer that is handling the agency's ever growing processing power needs. The reason that supercomputers are safer is that access to the computer is rarely direct and interactive. Programs are usually run on the computer by way of another computer that schedules them. This makes direct access harder. The storage sites attached to the supercomputer that contains the massive amounts of data collected by the BOM could have been targeted but this data alone would not necessarily have been very interesting and much harder to move out of these locations without detection. Finally, the BOM is connected through to other government agencies, including those involved in defence and security and so hackers could have got access to systems or networks that would allow them access beyond the Bureau's systems. What would the hackers been after? If the hackers were state-sponsored Chinese hackers such as the People's Liberation Army Unit 61398, then the target of the hack would have been wide-ranging but possibly focused on information related to Australian defence and security services and capabilities. The Bureau of Meteorology provides environmental monitoring services to these agencies in addition to its role of providing weather information to the public. The hackers could also have been after other intellectual property including software source code for the systems that the Bureau uses to model weather and make predictions. This would potentially be something of the greatest value to the Chinese because they could use this information to greatly improve their own capabilities. If the hackers had been simply been cyber criminals, they would have been more interested in getting information about individuals or anything that could be potentially leveraged into a financial gain at some later stage. What would the damage have been? The main damage relating to a cyber attack is not usually as a result of any specific damage done by the hackers during their forays through the systems. The damage is actually the cost of work that is needed to investigate and record what has happened, to then make sure that the hackers have not left behind any software that is continuing to spy or providing hackers with renewed access, and finally to plug whatever holes the hackers used to gain access in the first place. For most systems, this means either re-installing all of the software from scratch or restoring from a backup that is known to be safe. For the supercomputer, this is slightly harder because the system is in continuous use and can't be taken offline for extended periods of time. The costs of doing all of this come from the cost of people's time, especially consultants. Whether this amounts to "hundreds of millions of dollars" as reported by the ABC is doubtful. If the hack was done by the Chinese PLA, then it is unlikely that whatever security mechanisms are put in place will be completely effective in stopping a recurrence of this attack. Even less likely to have an effect is the recent agreement between US and Chinese leaders to not engage in corporate espionage of each other's countries. As reported by The Register, President Obama and President Xi Jinping managed to announce the deal without betraying the scepticism they both must have harboured that it would actually stop any hacking.


Ying K.,CAS Institute of Atmospheric Physics | Zhao T.,CAS Institute of Atmospheric Physics | Zheng X.,CAS Institute of Atmospheric Physics | Quan X.-W.,University of Colorado at Boulder | And 2 more authors.
Climate Dynamics | Year: 2016

The Community Land Model version 3.5 is driven by an observation-based meteorological dataset to simulate soil moisture over China for the period 1951–2008. A method for identifying the patterns of interannual variability that arise from slow (potentially predictable) and intraseasonal (unpredictable) variability is also applied; this allows identification of the sources of the predictability of seasonal soil moisture in China, during March–April–May (MAM), June–July–August (JJA), September–October–November (SON) and December–January–February (DJF). The potential predictability (slow-to-total) of the soil moisture above 1 m is high, with lowest value of 0.76 in JJA and highest value of 0.94 in DJF. The spatial distribution of the potential predictability comprises a northwest–southeast gradient, with a minimum center over East China and a maximum center over the northwest. The most important source of predictability is from the soil moisture persistence, which generally accounts for more than 50 % of the variability in soil moisture. The SSTs in the Indian Ocean, the North Atlantic and the eastern tropical Pacific Oceans are also identified as important sources of variability in the soil moisture, during MAM, JJA and SON/DJF, respectively. In addition, prolonged linear trends in each season are an important source. Using the slow principal component time series as predictands, a statistical scheme for the seasonal forecasting of soil moisture across China is developed. The prediction skills, in terms of the percentage of explained variance for the verification period (1992–2008), are 59, 51, 62 and 77 % during MAM–DJF, respectively. This is considerably higher than a normal grid prediction scheme. © 2016 Springer-Verlag Berlin Heidelberg


News Article | December 16, 2015
Site: www.reuters.com

Residents from Sydney's southern suburb of Kurnell assess the damage from a houses's roof which had blown down the street following a rare tornado, December 16, 2015. A truck lays overturned onto a car following strong winds at a Kurnell industrial park after a rare tornado hit the Sydney suburb December 16, 2015. A resident in Sydney's southern suburb of Kurnell assesses the damage to her house following a tornado, December 16, 2015. A man takes pictures of damage to cars following a rare tornado in the Sydney suburb of Kurnell, December 16, 2015. A resident from Sydney's southern suburb of Kurnell walks his dog past a house roof which had been blown down the street following a rare tornado, December 16, 2015. A car sits among factory roof debris with its windows smashed alongside an oil refinery following a rare tornado in the Sydney suburb of Kurnell, December 16, 2015. An emergency worker chainsaws a tree that destroyed a wall following a tornado in the Sydney suburb of Kurnell, December 16, 2015. A fireman assesses the damage to a house after its roof was torn off during a tornado in the Sydney suburb of Kurnell, December 16, 2015. A motorist assesses the damage to her car after a tornado hit the Sydney suburb of Kurnell, December 16, 2015. An emergency worker chainsaws a tree that destroyed a wall following a tornado in the Sydney suburb of Kurnell, December 16, 2015. Workers at a warehouse move a crate after the building's roof was torn off during a rare tornado in the Sydney suburb of Kurnell, December 16, 2015. The Bureau of Meteorology (BOM) issued the rare tornado warning around midday as the dangerous storm swept up the coast from Sydney's south, forcing some international and domestic flights to be diverted to other cities. A Reuters witness described widespread damage at an industrial park in the hard-hit Kurnell neighborhood near the southern beachside suburb of Cronulla. "We really had no warning. The sky just went really black and we had this massive clap of thunder," said Meredith Sullivan, a 48-year-old worker at the industrial park. "Then the gusts of winds were just horrific, you could hear the roof starting to lift and debris was starting to fly around. All the cars were pretty much destroyed," she said. Kurnell, which is close to Sydney's airport, was closed to all but emergency services, who were assessing the damage. Wind gusts as high as 213 kmh (132 mph) were recorded there. "There is obvious evidence that we have had a tornado go through Cronulla today," BOM meteorologist Alan Sharp told Sydney media. Social media was swamped by pictures of the huge, dark storm as it engulfed the harbor city, plunging a 25 degree Celsius (77 Fahrenheit) summer's day into darkness. A shopping center in Sydney's eastern suburbs was also evacuated after part of its roof collapsed in the storm, media reports showed, and one woman suffered minor injuries. Some 6,000 homes were reportedly without power south of the city and rescue services received more than 200 calls for help in the city. "The tornado risk has now subsided but there is a very good chance of more thunderstorm activity for the rest of today," said BOM senior meteorologist James Taylor. Australia is experiencing an El Niño weather pattern, a phenomenon associated with extreme droughts, storms and floods, which is expected to become one of the strongest on record, the U.N. weather agency said earlier this year.


News Article | December 1, 2016
Site: www.theguardian.com

Most of Australia can expect a hotter-than-average December, with temperatures being forced up by both regional climate patterns and a global upwards trend. Temperatures were forecast to peak between 29C and 34C on Thursday, the first day of summer, in all states bar Victoria and Tasmania. Melbourne and Hobart could look forward to highs of 21C and 24C. Queensland would be the worst affected, with Friday expected to be Brisbane’s hottest December day in 15 years peaking at 38C. Severe heatwave conditions forecast in southern and central parts of the state were forecast to continue into early next week. The Bureau of Meteorology (BoM) warned residents to be mindful of the impact of heat stress. There were also low- to severe-intensity heatwave conditions across northern Western Australia and the Top End of the Northern Territory. Almost all of Australia could expect drier-than-average conditions in December, with a 70 to 80% chance of below-average rainfall across most of the eastern part of the country. Above-average temperatures were forecast for days and nights across eastern and northern Australia for the entire summer through to February. The higher-than-usual pressures in the short term were the result of a climate driver known as the Southern Annular Mode, typically associated with reduced rainfall and higher temperatures. It was forcing wind systems further north than normal, holding monsoon weather at bay while moving air far across the continent. “It acts a bit like a wall that blocks the influence of the tropical wet season,” said Andrew Watkins, the acting head of climate monitoring and prediction at BoM. The combination has resulted in severe fire danger for parts of NSW, Queensland, WA and ACT, and that risk would persist with the drier and hotter conditions over the summer. The second-wettest winter on record had encouraged grass growth, prompting concerns about fast-running grass fires, particularly on the urban fringe, said Watkins. The Bushfire and Natural Hazards Cooperative Research Centre said the fire risk was predominately in grassland areas of Victoria and NSW. Cyclone season is not set to begin in earnest until January, but Watkins said an average to above-average season – typically 11 cyclones – was forecast. Last season there were only three, a record low, because of an “exceptionally strong” El Niño. “We don’t want people to be complacent because not much happened last year ... It was not typical by any means.” BoM’s seasonal outlook for December to February also warned that “Australian climate patterns were being influenced by the long-term increasing trend in global air and ocean temperatures”. This year has already been declared the hottest ever recorded. Watkins said it was difficult to break down the impact of climate change on weather in Australia compared with local patterns and drivers. “The reality is climate change is playing a role in all of our weather and climate these days,” he said.

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