Since the mid-1970s the climatic changes that have taken place in southwest Western Australia have generated a variety of impacts, the most prominent of which is a reduction in dam inflows of at least 50 percent. These impacts were the catalyst for the formation of the Indian Ocean Climate Initiative in 1998, a research partnership between two national research organizations and several state government departments and agencies. This paper describes the key scientific findings of the Initiative with respect to the nature of the climatic changes that have taken place within the region, explores the factors that might have caused these changes, and describes the most recent climate projections for the region. We reflect on the factors leading to the rapid acceptance of the research outcomes from the Initiative, the impact of the Initiative on policy development across Australia and its likely evolution post-2006.

In this study, we explore the relationships between seasonal Australian rainfall and the Southern Annular Mode (SAM). We produce two seasonal indices of the SAM: the Antarctic Oscillation Index (AOI), and an Australian regional version (AOIR) using ERA‐40 mean sea‐level pressure (MSLP) reanalysis data. The seasonal rainfall data are based on gridded monthly rainfall provided by the Australian Bureau of Meteorology. For the period 1958–2002 a significant inverse relationship is found between the SAM and rainfall in southern Australia, while a significant in‐phase relationship is found between the SAM and rainfall in northern Australia. Furthermore, widespread significant inverse relationships in southern Australia are only observed in winter, and only with the AOIR. The AOIR accounts for more of the winter rainfall variability in southwest Western Australia, southern South Australia, western and southern Victoria, and western Tasmania than the Southern Oscillation Index. Overall, our results suggest that changes in the SAM may be partly responsible for the current decline in winter rainfall in southern South Australia, Victoria, and Tasmania, but not the long‐term decline in southwest Western Australian winter rainfall. Copyright © 2006 Royal Meteorological Society.

Analysis of the annual cycle of intensity, extent, and width of the Hadley circulation across a 31-yr period from all existent reanalyses reveals a good agreement among the datasets. All datasets show that intensity is at a maximum in the winter hemisphere and at a minimum in the summer hemisphere. Maximum and minimum values of meridional extent are reached in the respective autumn and spring hemispheres. While considering the horizontal momentum balance, where a weakening of the Hadley cell (HC) is expected in association with a widening, it is shown here that there is no direct relationship between intensity and extent on a monthly time scale.All reanalyses show an expansion in both hemispheres, most pronounced and statistically significant during summer and autumn at an average rate of expansion of 0.558 decade 21 in each hemisphere. In contrast, intensity trends are inconsistent among the datasets, although there is a tendency toward intensification, particularly in winter and spring.Correlations between the HC and tropical and extratropical large-scale modes of variability suggest interactions where the extent of the HC is influenced by El Niñ o-Southern Oscillation (ENSO) and the annular modes. The cells tend to shrink (expand) during the warm (cold) phase of ENSO and during the low (high) phase of the annular modes. Intensity appears to be influenced only by ENSO and only during spring for the southern cell and during winter for the northern cell.

This meta-analysis has demonstrated that nutritional support supplemented with key nutrients results in a significant reduction in the risk of developing infectious complications and reduces the overall hospital stay in patients with critical illness and in patients with gastrointestinal cancer. However, there is no effect on death. These data have important implications for the management of such patients.

Changes in El Niño‐Southern Oscillation (ENSO) and the Walker Circulation can be routinely monitored using the Southern Oscillation Index (SOI). Here we show that the lowest 30‐year average value of the June–December SOI just occurred (i.e. in 1977–2006), and that this coincided with the highest recorded value in mean sea‐level pressure at Darwin, the weakest equatorial surface wind‐stresses and the highest tropical sea‐surface temperatures on record. We also document what appears to be a concurrent period of unprecedented El Niño dominance. However, our results, together with results from climate models forced with increasing greenhouse gas levels, suggest that the recent apparent dominance might instead reflect a shift to a lower mean SOI value. It seems that global warming now needs to be taken into account in both the formulation of ENSO indices and in the evaluation and exploitation of statistical links between ENSO and climate variability over the globe. This could very well lead to the development of more accurate seasonal‐to‐interannual climate forecasts.

We examined the effects of past and future climate change on natural snow cover in southeastern mainland Australia and assessed the role of snowmaking in adapting to projected changes in snow conditions. Snow-depth data from 4 alpine sites from 1957 to 2002 indicated a weak decline in maximum snow depths at 3 sites and a moderate decline in mid-to late-season snow depths (August to September). Low-impact and high-impact climate change scenarios were prepared for 2020 and 2050 and used as input for a climate-driven snow model. The total area with an average of at least 1 d of snow cover per year was projected to decrease by 10 to 39% by 2020, and by 22 to 85% by 2050. By 2020, the length of the ski season was projected to have decreased by 10 to 60%, while by 2050 the decrease was 15 to 99%. Based on target snow-depth profiles from May to September nominated by snowmaking managers at various ski resorts, the snow model simulated the amount of snow that is needed to be made each day, taking into account natural snowfall, snow-melt and the pre-existing natural snow depth. By the year 2020, an increase of 11 to 27% in the number of snow guns would be required for the low impact scenario, and 71 to 200% for the high impact scenario. This corresponds to changes in total snow volume of 5 to 17% for the low impact scenario to 23 to 62% for the high impact scenario. Therefore, with sufficient investment in snow guns, the Australian ski industry may be able to manage the effect of projected climate change on snow cover until at least 2020.KEY WORDS: Snow · Depth · Area · Duration · Australia · Climate · Change · Snowmaking Resale or republication not permitted without written consent of the publisherClim Res 35: [255][256][257][258][259][260][261][262][263][264][265][266][267][268][269][270] 2008 annual snow-cover extent since 1966, largely due to decreases in spring and summer snow cover since the mid-1980s over both the Eurasian and American continents (Robinson & Frei 2000). Surface observations for the northern hemisphere from show no significant change in winter snow extent, but a decrease in spring (Brown 2000). At most locations below 1800 m in northwestern USA, large decreases in waterequivalent snow depth from 1950-2000 coincide with significant increases in temperature, despite increases in precipitation (Groisman et al. 2004, Mote et al. 2005. Since the late 1940s, there has been a shift toward earlier snow-melt runoff in many rivers of northwestern America (Stewart et al. 2005).In the Australian region, there has been a warming of 0.9°C since 1900, most of which has occurred since 1950 (Nicholls & Collins 2006). Australian rainfall exhibits large annual and regional variability, including a decline in annual rainfall in the east since 1950 (Nicholls & Collins, 2006). Climate trends are likely to have had an effect on the Australian snowfields, but the large annual variability in snow season characteristics in the mainland Australian alpine region makes it difficult to detect trends. Fig. 1 shows ...

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One of the aims of developing new climate projections is to better address the requirements of stakeholders-particularly those who require less uncertainty and/or probabilistic information to work with. Projections are continually updated over time as more, and newer, climate model simulations of the future become available but this can introduce problems when it comes to interpreting large samples with differing results. Regional projections of rainfall are characterised by a high level of uncertainty, partly because of different sensitivities of the different models. Some models can be demonstrated to perform relatively poorly when assessed by their ability to simulate present-day means and variability and here we show that the uncertainty in model projections can potentially be reduced when the projection from these models are either discounted or ignored entirely. When applied to the Murray Darling Basin of south east Australia, it is possible to demonstrate a clustering of the results from the better performing models. These indicate that the rainfall changes to be expected as a result of increased greenhouse gas concentrations into the future are more likely to be at the drier end of the full set of model results. This occurs because the better performing models indicate decreases in winter and spring which are significantly different to the changes indicated by the other models. These results suggest that there are compelling reasons for discounting, if not entirely dismissing, some model results based on their failure to satisfy some basic performance criteria.