This paper describes a soil moisture data set from the 82,000 km2 Murrumbidgee River Catchment in southern New South Wales, Australia. Data have been archived from the Murrumbidgee Soil Moisture Monitoring Network (MSMMN) since its inception in September 2001. The Murrumbidgee Catchment represents a range of conditions typical of much of temperate Australia, with climate ranging from semiarid to humid and land use including dry land and irrigated agriculture, remnant native vegetation, and urban areas. There are a total of 38 soil moisture‐monitoring sites across the Murrumbidgee Catchment, with a concentration of sites in three subareas. The data set is composed of 0–5 (or 0–8), 0–30, 30–60, and 60–90 cm average soil moisture, soil temperature, precipitation, and other land surface model forcing at all sites, together with other ancillary data. These data are available on the World Wide Web at http://www.oznet.org.au.

An innovative approach to studying the effects of cloud seeding on precipitation is to focus on understanding the natural variability of precipitation and the microphysical responses to aerosol.

Numerical Weather Prediction (NWP) and climate models are sensitive to evapotranspiration at the land surface. This sensitivity requires the prediction of realistic surface moisture and heat fluxes by land surface models that provide the lower boundary condition for the atmospheric models. This paper compares simulations of a stand-alone version of the European Centre for Medium-Range Weather Forecasts (ECMWF) land surface scheme, or the Viterbo and Beljaars scheme (VB95), with various soil and vegetation parameter sets against soil moisture observations across the Murrumbidgee River catchment in southeast Australia. The study is, in part, motivated by the adoption of VB95 as the operational land surface scheme by the Australian Bureau of Meteorology in 1999.VB95 can model the temporal fluctuations in soil moisture, and therefore the moisture fluxes, fairly realistically. The monthly model latent heat flux is also fairly insensitive to soil or vegetation parameters. The VB95 soil moisture is sensitive to the soil and, to a lesser degree, the vegetation parameters. The model exhibits a significant (generally wet) bias in the absolute soil moisture that varies spatially. The use of the best Australia-wide available soils and vegetation information did not improve VB95 simulations consistently, compared with the original model parameters. Comparisons of model and observed soil moistures revealed that more realistic soil parameters are needed to reduce the model soil moisture bias. Given currently available continent-wide soils parameters, any initialization of soil moisture with observed values would likely result in significant flux errors. The soil moisture bias could be largely eliminated by using soil parameters that were derived directly from the actual soil moisture observations. Such parameters, however, are only available at very few point locations.

Observations of dry-season north Australian cloud lines (NACLs) that form in the Gulf of Carpentaria region of northern Australia and the sea-breeze circulations that initiate them are described. The observations were made during the 2002 Gulf Lines Experiment (GLEX) and include measurements made by an instrumented research aircraft. The observations are compared with numerical simulations made from a two-dimensional cloud-scale model. Particular emphasis is placed on the interaction between the east coast and west coast sea breezes near the west coast of Cape York Peninsula. The sea breezes are highly asymmetric due to the low-level easterly synoptic flow over the peninsula. The west coast sea breeze is well defined with a sharp leading edge since the opposing flow limits its inland penetration, keeping it close to its source of cold air. In contrast, the east coast sea breeze is poorly defined since it is aided by the easterly flow and becomes highly modified by daytime convective mixing as it crosses over the peninsula. Both the observations and the numerical model show that, in the early morning hours, the mature NACL forms at the leading edge of a gravity current. The numerical model simulations show that this gravity current arises as a westward-moving land breeze from Cape York Peninsula. Convergence at the leading edge of this land breeze is accompanied by ascent, which when strong enough produces cloud. Observations show that the decay of the NACL is associated with a decline in the low-level convergence and a weakening of the ascent.

South East Queensland, Australia, is explored through an 18-yr radar climatology and a two-season field campaign.

During the late afternoon on 16 November 2008 the Brisbane (Queensland, Australia) suburb of ''The Gap'' experienced extensive wind damage caused by an intense local thunderstorm. The CP2 research radar nearby detected near-surface radial velocities exceeding 43 m s 21 above The Gap while hail size reports did not exceed golf ball size, and no tornadoes were reported. The storm environment was characterized by a layer of very moist near-surface air and strong storm-relative low-level flow, whereas the storm-relative winds aloft were weak. While the thermodynamic storm environment contained a range of downdraft-promoting ingredients such as a ;4-km-high melting level above a ;2-km-deep layer with nearly dry-adiabatic lapse rates mostly collocated with dry ambient air, a ;1-km-deep stable layer near the ground would generally lower expectations of destructive surface winds based on the downburst mechanism. Once observed reflectivities exceed 70 dBZ, downdraft cooling due to hail melting and downdraft acceleration based on hail loading are found to likely become nonnegligible forcing mechanisms. The event featured the close proximity of a hydrostatically and dynamically driven mesohigh at the base of the downdraft to a dynamically driven mesolow associated with a low-level circulation. This proximity was instrumental in the anisotropic horizontal acceleration of the nearground outflow and the ultimate strength of the Gap storm surface winds. Weak storm-relative midlevel winds are speculated to have allowed the downdraft to descend close to the low-level circulation, which set up this strong horizontal perturbation pressure gradient.

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The southeast Queensland (SEQ) region of Australia is recognised for frequent thunderstorms documented through numerous studies including high-impact severe thunderstorm cases which have caused insured losses exceeding $1 billion AUD. Despite a modest body of scientific literature, basic questions regarding the role of climate, synoptic and local-scale (<10 km) processes affecting the variability of thunderstorms still remain. In an effort to advance these questions as part of the Coastal Convective Interactions Experiment (CCIE), this study integrates multiple datasets across an 18-year period (July 1997-June 2015) to provide a mesoscale climatological analysis of the SEQ hailstorms and associated environmental conditions. On a multi-year time-scale, the relationship between the El Niño Southern Oscillation and hailstorm frequency is consistent with previous studies. On synoptic scales, a southeasterly change situation coupled with a sea breeze was found to provide the most favourable environment for hailstorms, particularly for southwest SEQ. On the local scale, hail development within convective cells was found to be most frequent within the inland limb of the maritime air mass on sea-breeze days. This observation suggests the sea-breeze air masses may become favourable for convection after sufficient modification during inland propagation.