Estimation of Climate Change Impact on Mean Annual Runoff across Continental Australia Using Budyko and Fu Equations and Hydrological Models

Abstract

This paper presents the climate change impact on mean annual runoff across continental Australia estimated using the Budyko and Fu equations informed by projections from 15 global climate models and compares the estimates with those from extensive hydrological modeling. The results show runoff decline in southeast and far southwest Australia, but elsewhere across the continent there is no clear agreement between the global climate models in the direction of future precipitation and runoff change. Averaged across large regions, the estimates from the Budyko and Fu equations are reasonably similar to those from the hydrological models. The simplicity of the Budyko equation, the similarity in the results, and the large uncertainty in global climate model projections of future precipitation suggest that the Budyko equation is suitable for estimating climate change impact on mean annual runoff across large regions. The Budyko equation is particularly useful for data-limited regions, for studies where only estimates of climate change impact on long-term water availability are needed, and for investigative assessments prior to a detailed hydrological modeling study. The Budyko and Fu equations are, however, limited to estimating the change in mean annual runoff for a given change in mean annual precipitation and potential evaporation. The hydrological models, on the other hand, can also take into account potential changes in the subannual and other climate characteristics as well as provide a continuous simulation of daily and monthly runoff, which is important for many water availability studies.

Impacts of Climate Change on Mean Annual Water Balance for Watersheds in Michigan, USA

“…The Budyko water balance approach for estimating the climatic sensitivity has been widely applied in previous studies [8,[19][20][21][22]. However, studies relating groundwater (e.g., baseflow) to Budyko Hypothesis were relatively rare.…”

Comparison of future runoff projections using Budyko framework and global hydrologic model: conceptual simplicity vs process complexity

“…Most of these studies have been applied at single basins (Donohue et al, 2011;Jiang et al, 2015;Liang and Liu, 2014;Liu and McVicar, 2012;Roderick and Farquhar, 2011;Xu et al, 2014;Zhang X. et al, 2014) or multiple basins within a single region: USA (Chen et al, 2013;Wang and Hejazi, 2011;Carmona et al, 2014;Istanbulluoglu et al, 2012), Australia (Donohue et al, 2010(Donohue et al, , 2012Teng et al, 2012), China (Yang D. et al, 2007(Yang D. et al, , 2009Yang and Yang, 2011;Yang H. et al, 2014;Cong et al, 2015;Xiong and Guo, 2012;Yu et al, 2013) and Europe (Velde et al, 2014;Oudin et al, 2008). The global scale studies have also been conducted but mainly focusing on the development of the Budyko functional forms (Koster and Suarez, 1999;Zhang L. et al, 2001;Arora, 2002) and their parameters (Li et al, 2013;Williams et al, 2012).…”

“…A few examples include Teng et al (2012), who compared the Budyko runoff projections and hydrological model outputs driven by 15 GCMs over Australia. This study concluded that the Budyko equa-tion agrees with model projections over large regions, but underestimates runoff in wet regions and overestimates it in dry regions.…”

Including the dynamic relationship between climatic variables and leaf area index in a hydrological model to improve streamflow prediction under a changing climate

“…In southeastern Australia it has been projected that there will be a reduction in mean annual runoff of 10 % on average when different climate models are used as input to hydrological models (Cai and Cowan, 2008;Chiew et al, 2009;Roderick and Farquhar, 2011;Teng et al, 2012a;Vaze and Teng, 2011). These studies assessed the possible impacts of climate change on total runoff based on rainfall-runoff relationships which only considered first-order effects of changes in precipitation and temperature with subsequent impacts on evaporative demand.…”