Surface water numerical modelling for the Galilee subregion Product 2.6.1 for the Galilee subregion from the Lake Eyre Basin Bioregional Assessment

No abstract available

Surface water numerical modelling for the Gloucester subregion. Product 2.6.1 for the Gloucester subregion from the Northern Sydney Basin Bioregional Assessment

No abstract available

Surface water numerical modelling for the Gloucester subregion. Product 2.6.1 for the Gloucester subregion from the Northern Sydney Basin Bioregional Assessment

No abstract available

Opportunities to evaluate a Landscape hydrological model (AWRA-L) using global data sets

The Australian Water Resources Assessment system Landscape model (AWRA-L) aims to produce interpretable water balance component estimates covering all of Australia, and as much as possible agree with water balance observations, including point gauging data and satellite observations. The opportunities to evaluate AWRA-L water balance predictions in Australia are severely limited by the limited amount of field data (e.g. flux tower observations, soil moisture measurements) and the limited range of environments and conditions for which observations are available. Opportunities exist to further evaluate and improve AWRA-L model predictions by using global collations of in situ soil moisture, flux tower, and streamflow data available from the broader scientific community. To evaluate AWRA-L against these observations, global input data are required. We reviewed and compared results of published studies about meteorological data that could be used to parameterise AWRA-L globally. Review findings include: • Satellite-based rainfall performs better during warm seasons and in the tropics, although overestimating total rainfall. Reanalysis data outperforms satellite-based rainfall during winter and in higher latitudes. Gauge bias-corrected TRMM 3B42V6 reduces observed bias in many areas globally. A blending approach may enhance rainfall quality estimates on a global scale, using rainfall from reanalysis in higher latitudes and satellite estimates such as TRMM 3B42V6 in mid-latitudes. •Global monthly, annual and climatological surface temperature anomalies from reanalysis had very similar values. At the daily scale, compared daily maximum and minimum temperature probability density functions from ERA-40, JRA-25 and NCEP-DOE were dissimilar with large regional differences, but overall no reanalysis showed more skill than the other two when compared against regional observational temperature data. •Surface shortwave radiation derived from satellite data generally has smaller biases than reanalysis because they are more constrained by observations. Of the three satellite-based incoming shortwave radiation estimates, GEWEX-SRB appeared superior to the other two. Globally, the biases in the climatology of the re-analyses are considerable. The 60 year (1948-2008) Princeton Global Forcing (PGF) dataset with a spatial resolution of 1° and daily time step was considered an adequate compromise for trial simulations. PGF is based on the NCEP/NCAR reanalysis but uses several additional data sources to constrain and reduce bias in the meteorological variables. We implemented a prototype 1° resolution global hydrological model based on AWRA-L - referred to here as the World-Wide Water Resources Assessment system (W3RA). W3RA was parameterized with the same set of parameters used in AWRA-L except for baseflow coefficient, which was derived from a global analysis of base flow recession. In addition, a snow module was added to simulate snowmelt and snow accumulation. Other data used included land cover maps based on MODIS reflectance data, albedo climatology derived from white-sky albedo and wind speed climatology. As part of preliminary evaluation of W3RA, runoff estimates were compared against a Global Runoff Data Centre (GRDC) blend of observations and modeled runoff climatology. Ongoing evaluation will include comparisons against a quality controlled gauged daily flows in 167 unimpaired catchments located mostly in the tropics, a global data set of collated site soil moisture measurements, and evapotranspiration from a global network of flux towers

The Millennium Drought in southeast Australia (2001–2009): Natural and human causes and implications for water resources, ecosystems, economy, and society

The "Millennium Drought" (2001-2009) can be described as the worst drought on record for southeast Australia. Adaptation to future severe droughts requires insight into the drivers of the drought and its impacts. These were analyzed using climate, water, economic, and remote sensing data combined with biophysical modeling. Prevailing El Ni~no conditions explained about two thirds of rainfall deficit in east Australia. Results for south Australia were inconclusive; a contribution from global climate change remains plausible but unproven. Natural processes changed the timing and magnitude of soil moisture, streamflow, and groundwater deficits by up to several years, and caused the amplification of rainfall declines in streamflow to be greater than in normal dry years. By design, river management avoided impacts on some categories of water users, but did so by exacerbating the impacts on annual irrigation agriculture and, in particular, river ecosystems. Relative rainfall reductions were amplified 1.5-1.7 times in dryland wheat yields, but the impact was offset by steady increases in cropping area and crop water use efficiency (perhaps partly due to CO2 fertilization). Impacts beyond the agricultural sector occurred (e.g., forestry, tourism, utilities) but were often diffuse and not well quantified. Key causative pathways from physical drought to the degradation of ecological, economic, and social health remain poorly understood and quantified. Combined with the multiple dimensions of multiyear droughts and the specter of climate change, this means future droughts may well break records in ever new ways and not necessarily be managed better than past ones

How the performance of hydrological models relates to credibility of projections under climate change

Two approaches can be distinguished in studies of climate change impacts on water resources when accounting for issues related to impact model performance: (1) using a multi-model ensemble disregarding model performance, and (2) using models after their evaluation and considering model performance. We discuss the implications of both approaches in terms of credibility of simulated hydrological indicators for climate change adaptation. For that, we discuss and confirm the hypothesis that a good performance of hydrological models in the historical period increases confidence in projected impacts under climate change, and decreases uncertainty of projections related to hydrological models. Based on this, we find the second approach more trustworthy and recommend using it for impact assessment, especially if results are intended to support adaptation strategies. Guidelines for evaluation of global- and basin-scale models in the historical period, as well as criteria for model rejection from an ensemble as an outlier, are also suggested

Tendências de índices de extremos climáticos para a região de Manaus-AM Trends of extreme climatic indices for Manaus - AM region

Foram estudadas tendências nos índices de extremos climáticos baseados em dados de precipitação para três estações localizadas em Manaus e na região circunvizinha para o período de 1971-2007. Baseado nos resultados obtidos pode ser observado que houve aumento da precipitação total anual sobre a região estudada. A estação localizada na zona urbana de Manaus (INMET) teve aumento, com significância estatística, dos eventos de precipitação iguais ou superiores a 50 mm (R50mm), na precipitação máxima acumulada em cinco dias consecutivos (Rx5day) e nos dias úmidos (R95p), indicando que Manaus poderá sofrer com o aumento das chuvas extremas. Aumento das anomalias positivas de TSM no Oceano Pacífico Equatorial leva a um aumento dos dias consecutivos secos e diminuição dos eventos extremos de chuva e da precipitação total sobre a bacia amazônica. As anomalias positivas de TSM no Oceano Atlântico Sul induz o deslocamento da ZCIT mais ao sul do Equador levando a um aumento da precipitação sobre a região de Manaus. Os resultados obtidos aqui têm potencial para possíveis previsões das características da precipitação em Manaus.<br>Trends in the extreme climate indices based on precipitation data at three stations in and around the city of Manaus for the period 1971-2007 are studied. Based on the results obtained it can be observed that there was an increase of the annual total precipitation in the area studied. At the station located in the city of Manaus (INMET), the frequency of precipitation events with 50 mm (R50mm) or more, the amount precipitation in five consecutive days (Rx5day) and the number of wet days (R95p), showed an increase, with statistical significance, indicating that Manaus may suffer with the increase of the extreme rainfall events. An increase in the positive SST anomalies in the Equatorial Pacific Ocean induce an increase of the consecutive dry days and decrease of the extreme rainfall events and, consequently, in the total precipitation in the Amazon basin. The positive SST anomalies in the South Atlantic Ocean induce the displacement of ITCZ to the south of Equator causing an increase of the precipitation in the Manaus region. The results obtained here have potential for possible prediction of precipitation characteristics at Manaus

Case studies

The objective of this chapter is to let a representative cross-section of practitioners, drawn from several regions of the world, reflect on their experiences through short illustrations of the approaches they have adopted to address a PUB problem. The chosen case studies cover the full range of runoff predictions in ungauged basins, using a wide range of methods, in places across broad climatic and geographic gradients. We then undertook a limited assessment of PUB practice seen in the case studies from two perspectives: (i) what lessons can be learned from the experiences of the case studies towards strengthening the outcomes of the synthesis?, and (ii) how can the outcomes of the synthesis help advance the practice of PUB globally