BARRA v1.0: Kilometre-scale downscaling of an Australian regional atmospheric reanalysis over four midlatitude domains

Abstract

Abstract. The development of convection-permitting models (CPMs) in numerical weather prediction has facilitated the creation of km-scale (1–4 km) regional reanalysis and climate projections. The Bureau of Meteorology Atmospheric high-resolution Regional Reanalysis for Australia (BARRA) also aims to realise the benefits of these high-resolution models over Australian sub-regions for applications such as fire danger research, by nesting them in BARRA's 12 km regional reanalysis (BARRA-R). Four mid-latitude sub-regions are centred on Perth in Western Australia, Adelaide in South Australia, Sydney in New South Wales (NSW), and Tasmania. The resulting 29-year 1.5 km downscaled reanalyses (BARRA-C) are assessed for their added skill over BARRA-R and global reanalyses for near-surface parameters (temperature, wind and precipitation) at observation locations and against independent 5 km gridded analyses. BARRA-C demonstrates better agreement with point observations for temperature and wind, particularly in topographically complex regions and coastal regions. BARRA-C also improves upon BARRA-R in terms of intensity and timing of precipitation during the thunderstorm seasons in NSW, and spatial patterns of sub-daily rain fields during storm events. However, as a hindcast-only system, BARRA-C largely inherits the domain-averaged biases and temporal variations of biases from BARRA-R. Further, BARRA-C reflects known issues of CPMs: overestimation of heavy rain rates and rain cells, and underestimation of light rain occurrence.

A review of early severe weather applications of high‐resolution regional reanalysis in Australia

“…Contrary to BARRA‐R, BARRA‐C is run without a convective parameterization scheme, instead using model dynamics to represent vertical motion and moisture transport between the vertical levels. Further differences in the boundary layer, cloud microphysics and land surface parameterizations are described in Su et al, 2021. The horizontal boundary and 40 km model top conditions of BARRA‐C come from hourly BARRA‐R output.…”

“…This paper aims to document a number of applications of the high‐resolution reanalysis Bureau of Meteorology Atmospheric high‐resolution Regional Reanalysis for Australia (BARRA, Su et al, 2019, 2021), highlighting its potential for both foundational and applied research. BARRA offers the opportunity to study the detailed evolution of significant weather events in the Australian region and to characterize historical hazards, including their frequency, severity and seasonality.…”

Coastal winds and larval fish abundance indicate a recruitment mechanism for southeast Australian estuarine fisheries

“…This re-analysis product provides hourly wind speeds at a 12 km resolution over the Australian domain with downscaled 1.5 km resolution within several subdomains between 1990 and 2019. For all analyses in the present study, we used near-surface (10 m) wind data from the 1.5 km resolution data from within the Eastern New South Wales subdomain (Su et al, 2020). This 1.5 km reanalysis model demonstrates high agreement with observations, with higher skill than the 12 km, particularly in coastal areas (Su et al, 2020).…”

“…To provide a consistent estimate of winds, we used the wind speed and direction data from the Australian Bureau of Meteorology Atmospheric high-resolution Regional Reanalysis for Australia (BARRA; Su et al, 2019Su et al, , 2020. This re-analysis product provides hourly wind speeds at a 12 km resolution over the Australian domain with downscaled 1.5 km resolution within several subdomains between 1990 and 2019.…”

“…For all analyses in the present study, we used near-surface (10 m) wind data from the 1.5 km resolution data from within the Eastern New South Wales subdomain (Su et al, 2020). This 1.5 km reanalysis model demonstrates high agreement with observations, with higher skill than the 12 km, particularly in coastal areas (Su et al, 2020).…”