A.Seed@bom.gov.au +61 39669 4591 (A. Seed), P.Steinle@bom.gov.au +61 39669 4848 (P. Steinle) Abstract Assessment of the forecast precipitation is required before it can be used as input to hydrological models. Using radar observations in south-eastern Australia, forecast rainfall from the Australian Community Climate Earth-System Simulator (ACCESS) is evaluated for 2010 and 2011. Radar rain intensities were first calibrated to gauge rainfall data from four research rainfall stations at hourly time steps. It was shown that the Australian ACCESS model (ACCESS-A) overestimated rainfall in low precipitation areas and underestimated elevated accumulations in high rainfall areas. The forecast errors were found to be dependent on the rainfall magnitude. Since the cumulative rainfall observations varied across the area and through the year, the Relative Error (RE) in the forecasts varied considerably with space and time, such that there was no consistent bias across the study area. Moreover, further analysis indicated that both location and magnitude errors were the main sources of forecast uncertainties on hourly accumulations, while magnitude was the dominant error on daily time scale. Consequently, the precipitation output from ACCESS-A may not be useful for direct application in hydrological modelling, and pre-processing approaches such as bias correction or exceedance probability correction will likely be necessary for application of the Numerical Weather Prediction (NWP) outputs.

Streamflow modelling results from the GR4H and PDM hydrological models were evaluated in two Australian sub-catchments, using (1) calibration to streamflow and (2) joint-calibration to streamflow and soil moisture. Soil moisture storage in the models was evaluated against soil moisture observations from field measurements. The PDM had the best performance in terms of both streamflow and soil moisture estimations during the calibration period, but was outperformed by GR4H during validation. It was also shown that the soil moisture estimation was improved significantly by joint-calibration for the case where streamflow and soil moisture estimations were poor. In other cases, addition of the soil moisture constraint did not degrade the results. Consequently, it is recommended that GR4H be used, in preference to the PDM, in the foothills of the Murrumbidgee catchment or other Australian catchments with semi-arid to subhumid climate, and that soil moisture data be used in the calibration process.

In order to characterize the trophic state of the southern coastal waters of the Caspian Sea, trophic index (TRIX) as well as numerical analysis using cluster and discriminant analysis were employed in this study. Chemical and biological parameters (NO(3), NO(2), NH(4), PT, DO, and Chla) used in this study were collected seasonally from summer 1999 to spring 2000. A new trophic index developed by modification of TRIX indicated mesotrophic to eutrophic conditions for the Caspian Sea. Numerical analysis revealed three groups of the study area and it was found that the used methods are in good agreement. Both of them predicted poor to moderate conditions in the western part of the study area and the numerical classification predicted trophic conditions in the study area. However, TRIX was found to be a more accurate and suitable method. It performs more conservatively than the numerical classification and characterized lower classes of water quality for the stations in central and eastern parts of the study area.

Hydrological hazards have been extensive worldwide in recent times. In particular, there has been widespread flooding across much of Australia in response to extreme precipitation events. Hydrological modelling can be used to effectively manage the extensive effects of flood events, but the primary input for hydrological hind-, now-and forecasting of these events is reliable knowledge of both observed and forecast precipitation.