Subseasonal to Seasonal Climate Forecasts Provide the Backbone of a Near-Real-Time Event Explainer Service

The Bureau of Meteorology serves the Australian community to reduce its climate risk and is developing a suite of tools to explain the drivers of extreme events. Dynamical sub-seasonal to seasonal forecasts form the backbone of the service, potentially enabling it to be run in near real time

Dynamics and predictability of El Nino-Southern Oscillation: an Australian perspective on progress and challenges

Many scientific challenges remain for managing the risk of future ENSO impacts in countries like Australia that are strongly affected by ENSO event diversity

A robust error-based rain estimation method for polarimetric radar. Part II : case study

Rainfall estimation using polarimetric radar involves the combination of a number of estimators with differing error characteristics to optimize rainfall estimates at all rain rates. In Part I of this paper, a new technique for such combinations was proposed that weights algorithms by the inverse of their theoretical errors. In this paper, the derived algorithms are validated using the "CP2" polarimetric radar in Queensland, Australia, and a collocated rain gauge network for two heavy-rain events during November 2008 and a larger statistical analysis that is based on data from between 2007 and 2009. Use of a weighted combination of polarimetric algorithms offers some improvement over composite methods that are based on decision-tree logic, particularly at moderate to high rain rates and during severe-thunderstorm events.12 page(s

Low pressure systems off the New South Wales coast and associated hazardous weather: establishment of a database

11 page(s

Atmospheric trends explained by changes in frequency of short-term circulation patterns

Abstract The circulation of the atmosphere is subject to natural and anthropogenic forcings that alter the energy balance of the climate system. In each hemisphere the zonally averaged atmospheric circulation can be represented by a single overturning cell if viewed in isentropic coordinates, highlighting the connections between tropics and extratropics. Here we present clusters of the meridional atmospheric circulation based on reanalysis data. Our results reveal preferred global circulation regimes with two clusters in each solstice season. These clusters show strong trends in their occurrence in the last two decades of the 20th century coincident with the depletion of the low-stratospheric ozone over Antarctica. We hypothesize that a change in the occurrence of short-term circulation regimes may lead to some long-term atmospheric trends. Finally, we show a strong coupling between the atmospheric circulation in boreal and austral winters and propose a mechanism linking anomalies in both seasons to the stratospheric ozone that requires confirmation with modelling experiments