TY - JOUR
T1 - Partitioning of precipitation into terrestrial water balance components under a drying climate
AU - Gardiya Weligamage, Hansini
AU - Fowler, Keirnan
AU - Peterson, Tim J.
AU - Saft, Margarita
AU - Peel, Murray C.
AU - Ryu, Dongryeol
N1 - Funding Information:
This research is funded by an Australian Research Council (ARC) Linkage Projects (LP180100796 and LP170100598) with partner organisations Victorian Department of Environment, Land, Water and Planning (DELWP), and Melbourne Water. Open access publishing facilitated by The University of Melbourne, as part of the Wiley ‐ The University of Melbourne agreement via the Council of Australian University Librarians.
Funding Information:
This research is funded by an Australian Research Council (ARC) Linkage Projects (LP180100796 and LP170100598) with partner organisations Victorian Department of Environment, Land, Water and Planning (DELWP), and Melbourne Water. Open access publishing facilitated by The University of Melbourne, as part of the Wiley - The University of Melbourne agreement via the Council of Australian University Librarians.
Publisher Copyright:
© 2023. The Authors.
PY - 2023/5
Y1 - 2023/5
N2 - To accurately project future water availability under a drying climate, it is important to understand how precipitation is partitioned into other terrestrial water balance components, such as fluxes (evaporation, transpiration, runoff) and changes in storage (soil moisture, groundwater). Many studies have reported unexpected large runoff reductions during drought, particularly for multi-year events, and some studies report a persistent change in partitioning even after the meteorological drought has ended. This study focused on understanding how actual evapotranspiration (AET) and change in subsurface storage (ΔS) respond to climate variability and change, examining Australia's Millennium Drought (MD, 1997–2009). The study initially conducted a catchment-scale water balance analysis to investigate interactions between ΔS and AET. Then the water balance analysis was extended to regional scale to investigate ΔS using interpolated rainfall and discharge with remotely sensed AET. Lastly, we evaluated conceptual rainfall-runoff model performance of two commonly used models against these water balance estimates. The evaluation of water-balance-derived ΔS against Gravity Recovery and Climate Experiment (GRACE) estimates shows a significant multiyear storage decline; however, with different rates. In contrast, AET rates (annualized) remained approximately constant before and during the MD, contrasting with some reports of evapotranspiration enhancement elsewhere. Overall, given AET remained approximately constant, drought-induced precipitation reductions were partitioned into ΔS and streamflow. The employed conceptual rainfall-runoff models failed to realistically represent AET during the MD, suggesting the need for improved conceptualization of processes. This study provides useful implications for explaining future hydrological changes if similar AET behavior is observed under a drying climate.
AB - To accurately project future water availability under a drying climate, it is important to understand how precipitation is partitioned into other terrestrial water balance components, such as fluxes (evaporation, transpiration, runoff) and changes in storage (soil moisture, groundwater). Many studies have reported unexpected large runoff reductions during drought, particularly for multi-year events, and some studies report a persistent change in partitioning even after the meteorological drought has ended. This study focused on understanding how actual evapotranspiration (AET) and change in subsurface storage (ΔS) respond to climate variability and change, examining Australia's Millennium Drought (MD, 1997–2009). The study initially conducted a catchment-scale water balance analysis to investigate interactions between ΔS and AET. Then the water balance analysis was extended to regional scale to investigate ΔS using interpolated rainfall and discharge with remotely sensed AET. Lastly, we evaluated conceptual rainfall-runoff model performance of two commonly used models against these water balance estimates. The evaluation of water-balance-derived ΔS against Gravity Recovery and Climate Experiment (GRACE) estimates shows a significant multiyear storage decline; however, with different rates. In contrast, AET rates (annualized) remained approximately constant before and during the MD, contrasting with some reports of evapotranspiration enhancement elsewhere. Overall, given AET remained approximately constant, drought-induced precipitation reductions were partitioned into ΔS and streamflow. The employed conceptual rainfall-runoff models failed to realistically represent AET during the MD, suggesting the need for improved conceptualization of processes. This study provides useful implications for explaining future hydrological changes if similar AET behavior is observed under a drying climate.
KW - climate change
KW - evapotranspiration
KW - multiyear drought
KW - rainfall-runoff modeling
KW - terrestrial water storage dynamics
KW - water balance partitioning
UR - http://www.scopus.com/inward/record.url?scp=85160416089&partnerID=8YFLogxK
U2 - 10.1029/2022WR033538
DO - 10.1029/2022WR033538
M3 - Article
AN - SCOPUS:85160416089
SN - 0043-1397
VL - 59
JO - Water Resources Research
JF - Water Resources Research
IS - 5
M1 - e2022WR033538
ER -