Australian rainfall trends and their relation to the southern oscillation index

Chowdhury, R. K.; Beecham, Simon

doi:10.1002/hyp.7504

Cited by 97 publications

(81 citation statements)

References 42 publications

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“…Consistent with their speculation, a weak but significant correlation of June-August (JJA) rainfall with the Southern Oscillation index (SOI) and the dipole mode index (DMI) has been reported by Risbey et al (2009). Nonetheless, during the period over which SWA rainfall has decreased there has been no significant trend in the SOI and therefore it cannot be linked to the long-term trends in rainfall over the region (Chowdhury and Beecham 2010;Nicholls 2010). …”

Section: Introductionmentioning

confidence: 71%

Rainfall Changes over Southwestern Australia and Their Relationship to the Southern Annular Mode and ENSO

2014

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Since the 1970s, winter rainfall over coastal southwestern Australia (SWA) has decreased by 10%-20%, while summer rainfall has been increased by 40%-50% in the semiarid inland area. In this paper, a K-means algorithm is used to cluster rainfall patterns directly as opposed to the more conventional approach of clustering synoptic conditions (usually the mean sea level pressure) and inferring the associated rainfall. It is shown that the reduction in the coastal rainfall during winter is mainly due to fewer westerly fronts in June and July. The reduction in the frequency of strong fronts in June is responsible for half of the decreased rainfall in June-August (JJA), whereas the reduction in the frequency of weaker fronts in June and July accounts for a third of the total decrease. The increase in rainfall inland in December-February (DJF) is due to an increased frequency of easterly troughs in December and February. These rainfall patterns are linked to the southern annular mode (SAM) index and Southern Oscillation index (SOI). The reduction in coastal rainfall and the increase in rainfall inland are both related to the predominantly positive phase of SAM, especially when the phase of ENSO is neutral.

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Section: Introductionmentioning

confidence: 71%

Rainfall Changes over Southwestern Australia and Their Relationship to the Southern Annular Mode and ENSO

2014

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“…Review of hydrological records collected in different parts of the world has provided evidence of regime-like or quasi-periodic climate behaviour and of systematic trends in key climate variables due to climate change and/or climate variability (Gallant et al, 2007;Fu et al, 2008;Ma et al, 2008;Lu, 2009, Chowdhury andBeecham, 2009;Villarini et al, 2009). As evidence, Australian average surface temperature has increased over the past 98 years, where the last two decades have been particularly warm, with the warmest year on record occurring during 2005 as shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…In general, the spatial pattern of the trends in annual precipitation can be separated into two main regions: to the west where the rain is increasing, and the east where precipitation has been decreasing, especially during the last 30 years. Chowdhury and Beecham (2009) investigated the monthly rainfall trends and their relation to the southern oscillation index (SOI) at ten rainfall stations across Australia covering all state capital cities. The outcomes of their assessment revealed decreasing trends of rainfall depth at two stations (Perth airport and Sydney Observatory Hill), no significant trends were found in the Melbourne, Alice Springs and Townsville rainfall data, where the remaining five stations showed increasing trends of monthly rainfall depth.…”

Section: Introductionmentioning

confidence: 99%

Preliminary Analysis of Trends in Australian Flood Data

Ishak¹,

Rahman²,

Westra³

et al. 2010

World Environmental and Water Resources Congress 2010

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In recent years, the potential impacts of climate variability and change on the hydrologic regime have received a great deal of attention from researchers. Review of hydrological data recorded in different parts of the world has provided evidence of regime-like or quasiperiodic climate behaviour and of systematic trends in key climate variables due to climate change and/or climate variability. It has been established that a changing climate will have notable impacts on the rainfall runoff process, and thus hydrologic time series (e.g., flood data) can no longer be assumed to be stationary. A failure to take such change/variability into account can lead to underestimation/overestimation of the design flood estimate, which in turn will have important implications on the design and operation of water infrastructures. This paper presents preliminary results from a study aimed to identify the nature of time trends in flood data in the Australian continent with the final objective of assessing the impacts of climatic change on regional floods in Australia. This research is being carried out as a part of the on-going revision of Australian Rainfall and Runoff -the national guide of design flood estimation in Australia. For this study, 491 suitable stations with flood data in the range of 30 to 97 years have been selected across the Australian continent. Two trend tests are applied: Mann-Kendall test and Spearman's Rho test to the data set. Preliminary trend analysis results show that about 30% of the selected stations show trends in annual maxima flood series data, with downward trends in the southern part of Australia and upward trends in the northern part. Further investigation is needed before any firm conclusion can be made about the trends in Australian flood data. Future work aims to address the influence of spatial correlation and autocorrelation on the ability to detect trend in annual maximum flood series data in Australia and assess the relationship between the observed trends in annual maximum flood data and other meteorological variables.

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“…Additionally, Atmosphere 2018, 9, 7 5 of 14 this method is simple, robust and can cope with missing values and values below a detection limit. The non-parametric Mann-Kendall test was recommended for identifying significant trends [32], such as precipitation, air temperature, hydrological data, water level, and drought in many regions across the world [33].…”

Section: Calculation Of the Speimentioning

confidence: 99%

Analysis of the Spatio-Temporal Patterns of Dry and Wet Conditions in Central Asia

Chen

et al. 2018

Atmosphere

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Drought has become an important threat to industrial and agricultural production and human activities in Central Asia. Using the Standardized Precipitation Evapotranspiration Index (SPEI), we explored the spatial and temporal patterns of dry and wet changes in Central Asia from 1930-2014. The Mann-Kendall trend test and empirical orthogonal function analysis were used to analyze the characteristics of drought in the interannual and seasonal scales. The results showed that the interannual SPEI index in Central Asia presented a distinct phased feature, in the late 1930s, 1970s and 1990s, three consecutive periods of drought occurred. Seasonal SPEI presented different characteristics, with no obvious drying trends in spring and summer. Autumn and winter showed a wet trend. While an obviously wetting tendency has been detected for the winter season, it started in the mid-1950s. Spatially, drought frequency is 42.87% over the entire region of Central Asia from 1930 to 2014. Kyrgyzstan and Tajikistan are wet relative to other countries in Central Asia, with the frequency of drought occurring at 41.6% and 41.9%, respectively; lower than the average frequency of drought in Central Asia. The average frequency of drought in Kazakhstan is 43.1%. Droughts frequently occur in the central and southern parts of Kazakhstan, with the frequency of drought reaching 46.76%. Droughts hardly occur in eastern of Kazakhstan, as well as in the northeastern region. Turkmenistan and Uzbekistan are the two driest countries in Central Asia, especially in the desert region. The frequency of drought was 50.68% and 47.64% respectively.

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Australian rainfall trends and their relation to the southern oscillation index

Cited by 97 publications

References 42 publications

Rainfall Changes over Southwestern Australia and Their Relationship to the Southern Annular Mode and ENSO

Rainfall Changes over Southwestern Australia and Their Relationship to the Southern Annular Mode and ENSO

Preliminary Analysis of Trends in Australian Flood Data

Analysis of the Spatio-Temporal Patterns of Dry and Wet Conditions in Central Asia

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