Extreme Rainfall Variability in Australia: Patterns, Drivers, and Predictability*

Abstract

Leading patterns of observed monthly extreme rainfall variability in Australia are examined using an empirical orthogonal teleconnection (EOT) method. Extreme rainfall variability is more closely related to mean rainfall variability during austral summer than in winter. The leading EOT patterns of extreme rainfall explain less variance in Australia-wide extreme rainfall than is the case for mean rainfall EOTs. The authors illustrate that, as with mean rainfall, the El Niño-Southern Oscillation (ENSO) has the strongest association with warmseason extreme rainfall variability, while in the cool season the primary drivers are atmospheric blocking and the subtropical ridge. The Indian Ocean dipole and southern annular mode also have significant relationships with patterns of variability during austral winter and spring. Leading patterns of summer extreme rainfall variability have predictability several months ahead from Pacific sea surface temperatures (SSTs) and as much as a year in advance from Indian Ocean SSTs. Predictability from the Pacific is greater for wetter-than-average summer months than for months that are drier than average, whereas for the Indian Ocean the relationship has greater linearity. Several cool-season EOTs are associated with midlatitude synoptic-scale patterns along the south and east coasts. These patterns have common atmospheric signatures denoting moist onshore flow and strong cyclonic anomalies often to the north of a blocking anticyclone. Tropical cyclone activity is observed to have significant relationships with some warm-season EOTs. This analysis shows that extreme rainfall variability in Australia can be related to remote drivers and local synoptic-scale patterns throughout the year.

Investigation into the Potential use of Inland Saline Groundwater for the Production of Live Feeds for Commercial Aquaculture Purposes

“…As a global example, Israel now has to deal with both dry land salinity and government-imposed water restrictions due to compromised land and water scarcity, situations that are exceedingly familiar to Australian farmers due to a fundamentally El-Nino/La Nina-based climatic system [38]. Many authors [8,10,38] indicate that this is becoming common in many parts of the world.…”

“…Many authors [8,10,38] indicate that this is becoming common in many parts of the world. Crop farmers invariably experience difficulties in sowing a crop, or produce crops of poor yield because of dry land salinity or increasing soil salinity that has stemmed from irrigation practices.…”

Interannual rainfall variability over China in the MetUM GA6 and GC2 configurations

“…The EOT method identifies independent regional patterns of coherent rainfall variability. The associated time series can be used to connect the patterns to regional and large-scale atmospheric and coupled atmosphereocean mechanisms, as Stephan et al (2017a, b) demonstrated for China and as was previously shown for other regions (Smith, 2004;Rotstayn et al, 2010;Klingaman et al, 2013;King et al, 2014).…”

A comprehensive analysis of coherent rainfall patterns in China and potential drivers. Part II: intraseasonal variability

“…The EOT method has been successfully demonstrated for interannual precipitation variability (Smith 2004;Rotstayn et al 2010;Klingaman et al 2013;King et al 2014) and for intraseasonal extreme precipitation (King et al 2014). In Part I of this study (Stephan et al 2017) the method was shown to successfully reproduce known patterns of interannual precipitation variability in China.…”