This paper introduces a collaborative Australian Bureau of Meteorology and China Meteorological Administration project that used atmospheric river analysis to explore detailed characteristics of atmospheric moisture transport embedded in the monsoon system.

This paper compares two typical atmospheric river (AR) events in China and Australia during the boreal summer (austral winter) of 2016, which produced record-breaking rainfall in North China and a rainfall belt across the Australian continent. We found that ARs operating in China and Australia have different features and mechanisms. Furthermore, we assessed the numerical weather prediction model, ACCESS-APS2, in forecasting these two AR events and found that it is better at forecasting ARs than rainfall location and intensity. AR analysis is a valuable diagnosis for supporting rainfall forecasts in the two regions.

In this study, we explored why atmospheric rivers in East Asia and Australia tend to peak during May–August, which is the boreal summer in East Asia but the cool season in Australia. We attributed this to the close linkage between subtropical highs in the western Pacific and Australian regions. Furthermore, we showed that two ARs, simultaneously presenting in both regions, most likely occurred in an El Niño decaying phase due to its delayed impacts on subtropical highs.

Atmospheric rivers (ARs) are known to contribute to heavy rainfall to the midlatitudes, but it is still unclear how they act on East Asian events, where severe flood disasters are on the rise. We investigated the potential connections between ARs and heavy rainfall over the Yangtze Plain in China and found that ARs embedded within the Asian monsoon flow provide a favourable climatic background for steady moisture supply to summer rainfall in East Asia, with WPSH a key factor in this moisture transport. Operational system ACCESS-S1 skillfully forecasted such subseasonal moisture transport and may prove useful for applying AR predictions to guide subseasonal rainfall forecasts.

While ARs are known to influence extreme rainfall events and associated natural disasters in American and European regions, little is known about their impact on extreme rainfall in the monsoon regions of Australian and Asia. For the first time, we systematically documented AR spatial distributions and their seasonal and interannual variations in China and Australia. We identified the moistures sources for ARs in both regions and a strong tropical influence on their formation and development.

In this study, we analysed historical and future simulations of atmospheric rivers (ARs) in the Australia-Asian region using 17 CMIP5 models and RCP8.5 simulations. Under current climate conditions, multi-model-ensemble results offer similar AR climatology and seasonality as derived from reanalysis data. They further simulate increased AR frequency and size in most of the region but reduced ARs in southern and eastern China in boreal summer associated with changes in Western North Pacific Subtropical High (WNPSH). AR analysis offers new insight to understand potential monsoon changes under warmed climate.

The U.S. National Weather Service and the Australian Bureau of Meteorology are on similar journeys to streamline the forecast production process. In both organisations, streamlining has developed regionally, and in Australia it is now being adopted nationally. This is freeing up forecaster time for other activities such as decision support and a focus on high-impact weather. A variety of lessons have been learned regarding how to achieve effective change in weather forecast production, through grassroots engagement and management support.

We describe how and why the Bureau of Meteorology is changing the way forecasts are produced, from a labour-intensive approach to a more streamlined approach. We describe the essence of the forecast process using a case study to demonstrate a situation in which meteorologists use their professional judgement to modify what would otherwise be a largely automated forecast service.

Predictions of dangerous weather conditions for bushfires are now available in a consistent form including seasonal predictions out to several months ahead and climate change projections through this century. These predictions are calibrated to an observations-based data set covering historical records back to 1950, resulting in a seamless suite of predictions and historical records. These new products have already helped improve services, including enhanced long-range planning as well as climate adaptation capabilities, for enhanced resilience and disaster risk reduction relating to natural hazards.

This paper provides some examples of the UK Met Office’s international climate service activities from projects in Europe, China and small island Commonwealth states, all to benefit society through facilitating improved decision-making. The paper highlights challenges, such as gaps between users’ needs and scientific capability, technical language, user engagement, and sustainability of climate services beyond project lifespans. Approaches that have proven successful are highlighted, such as collaboration, prototyping and the importance of effective user engagement.

The delivery of environmental information through augmented reality displays is demonstrated through the development of four mobile applications. These mobile applications show how machine learning methods and augmented reality may be combined to create localised, context aware and user-centric environmental information delivery channels. This work demonstrates the potential of augmented reality to profoundly alter the ways in which environmental information is delivered and presented to data consumers.

The heuristic multiple regression model of Lean and Rind (2008) was applied to seven different global air temperature datasets to separate trend due to anthropogenic forcing from other components. The commonly used energy balance model of Gregory at al. (2002) was then applied to those trends in combination with forcing and global heating values from the literature, enabling estimates of equilibrium climate sensitivity and transient climate response. The seven results were very similar, and consistent with estimates published by the IPCC.

The Bureau of Meteorology records 1-min average air temperature at automatic weather stations as the value measured for the last second of the minute, arguing the system’s thermal inertia smooths temperature over the previous 40–80 s. Temperatures measured every second across 37 days at two sites enabled characterisation of system response time from the difference between 1-s values and 60-s averages. The analysis confirmed that temperature measured at the last second of each minute provides valid 1-min averages

The ACCESS-AM2 atmosphere-only climate model is introduced using experiments with two land-surface models. Model evaluation shows close agreement with observed global-mean temperature and precipitation is simulated reasonably well. Selected features of the atmospheric circulation are discussed, while for the Australian region important drivers of climate variability are also reviewed. ACCESS-AM2 has reduced errors for both temperature and precipitation of around 15–20% compared to older versions of the model, while the two different land-surface schemes perform similarly.

Thirty tropical cyclones (TCs) have made landfall in New South Wales (NSW), Australia, between 1863 and 2013. Periods of high and low TC activity in NSW are influenced by the combined modes of the El Niño Southern Oscillation and Interdecadal Pacific Oscillation. This study improves our understanding of TC risk for NSW and should improve risk management and future storm forecasting in NSW.

This paper describes the Australian Earth System Model, ACCESS-ESM1.5, and its submission to the 6th phase of the Coupled Model Intercomparison Project (CMIP6). Simulation results for the physical climate and the carbon cycle are evaluated for present day against observations and an earlier version of ACCESS-ESM.

The effect of assimilating synthetic central pressure observations into a simulation of Tropical Cyclone Owen was examined within a convective-scale numerical prediction system. Without these observations, the cyclone did not develop into a realistically intense storm. However, the cyclone track was not easily predicted, and was not improved by the additional synthetic observations.

ACCESS-CM2 has been developed for a wide range of climate modelling research applications, and firstly configured as one of Australia’s contributions to the Coupled Model Intercomparison Project Phase 6 (CMIP6). This paper describes the model components, physical configuration, preindustrial spin-up strategy and process, and presents the spin-up climatology for preliminary evaluation of the model performance. This paper is deemed as a seminal part of the ACCESS-CM2 delivery to CMIP6.

This paper describes a sequence of severe weather events along the Australian subtropical coast in the nineteenth century which was much worse than anything experienced in the twentieth or twenty-first centuries. The two highest floods occurred in Brisbane City and record rainfall was registered. Wave attack over the period caused a breach in Stradbroke Island dividing it into North and South Stradbroke Islands. The coastal ocean damage over the period is examined with events since, and only the 1967 Gold Coast erosion is comparable. Ocean damage was found to be more likely during positive phases of the Southern Oscillation Index.

The Fifth Assessment Report of the Intergovernmental Panel on Climate Change concluded that the global sea level rise in 2005–2100 would likely surpass the increase rate of 1971–2010. This study is focused on the southern hemisphere oceans, evaluating the sea surface height trends, simulated by the Brazilian Earth System Model (BESM) and three other selected models, in two proposed future scenarios. The causes are mainly attributable to thermal expansion, especially within 35–60°S in the Atlantic and Indian oceans.

We present the first high resolution, long-term climatology of wind change strength and frequency associated with elevated fire danger over Victoria, Australia. Using a high-resolution gridded data set, we showed that the southern and southwestern parts of Victoria had the highest frequency of strong wind changes and fire danger events occurring on the same day. As the most catastrophic impacts from bushfires in Victoria tend to occur on such days, this information offers a hitherto unavailable resource to both meteorologists and fire managers.

A summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for spring 2017, including an account of seasonal rainfall and temperature for the Australian region. An unusually late La Niña became established by the end of spring, and the season saw exceptional September warmth over eastern Australia. This was Australia’s equal-fifth-warmest spring on record, and drier than average overall for Australia as a whole.

This is a summary of austral autumn 2018; the second warmest on record for land and fourth warmest for land and ocean combined. Against a drier than average background, high rainfall caused flooding and displaced almost one million people in Kenya, while record-breaking rain fell over Australia’s southernmost state. Notable too was an extremely rare, late-season subtropical cyclone, which formed off South America’s west coast, and midseason records for maximum temperature tumbled when extensive and prolonged heatwaves visited mainland Australia.

A summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for austral winter 2018. Over most major land areas in the southern hemisphere, conditions were warmer and drier than average.

This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for spring 2018; an account of seasonal rainfall and temperature for the Australian region and broader southern hemisphere is also provided. A positive phase of the Indian Ocean Dipole developed during the season, and the central and eastern equatorial Pacific were warmer than average without reaching El Niño thresholds.