Global hydrological droughts in the 21st century under a changing hydrological regime
Climate change very likely impacts future hydrological drought characteristics across the world. Here, we quantify the impact of climate change on future low flows and associated hydrological drought characteristics on a global scale using an alternative drought identification approach that...
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doaj-3daa0183bc6c4c3ab93872bd1d62523a2020-11-24T23:24:09ZengCopernicus PublicationsEarth System Dynamics2190-49792190-49872015-01-016111510.5194/esd-6-1-2015Global hydrological droughts in the 21st century under a changing hydrological regimeN. Wanders0Y. Wada1H. A. J. Van Lanen2Department of Physical Geography, Faculty of Geosciences, Utrecht University, Utrecht, the NetherlandsDepartment of Physical Geography, Faculty of Geosciences, Utrecht University, Utrecht, the NetherlandsHydrology and Quantitative Water Management Group, Centre for Water and Climate, Wageningen University, Wageningen, the NetherlandsClimate change very likely impacts future hydrological drought characteristics across the world. Here, we quantify the impact of climate change on future low flows and associated hydrological drought characteristics on a global scale using an alternative drought identification approach that considers adaptation to future changes in hydrological regime. The global hydrological model PCR-GLOBWB was used to simulate daily discharge at 0.5° globally for 1971–2099. The model was forced with CMIP5 climate projections taken from five global circulation models (GCMs) and four emission scenarios (representative concentration pathways, RCPs), from the Inter-Sectoral Impact Model Intercomparison Project. <br><br> Drought events occur when discharge is below a threshold. The conventional variable threshold (VTM) was calculated by deriving the threshold from the period 1971–2000. The transient variable threshold (VTM<sub>t</sub>) is a non-stationary approach, where the threshold is based on the discharge values of the previous 30 years implying the threshold to vary every year during the 21st century. The VTM<sub>t</sub> adjusts to gradual changes in the hydrological regime as response to climate change. <br><br> Results show a significant negative trend in the low flow regime over the 21st century for large parts of South America, southern Africa, Australia and the Mediterranean. In 40–52% of the world reduced low flows are projected, while increased low flows are found in the snow-dominated climates. <br><br> In 27% of the global area both the drought duration and the deficit volume are expected to increase when applying the VTM<sub>t</sub>. However, this area will significantly increase to 62% when the VTM is applied. The mean global area in drought, with the VTM<sub>t</sub>, remains rather constant (11.7 to 13.4%), compared to the substantial increase when the VTM is applied (11.7 to 20%). <br><br> The study illustrates that an alternative drought identification that considers adaptation to an altered hydrological regime has a substantial influence on future hydrological drought characteristics.http://www.earth-syst-dynam.net/6/1/2015/esd-6-1-2015.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
N. Wanders Y. Wada H. A. J. Van Lanen |
spellingShingle |
N. Wanders Y. Wada H. A. J. Van Lanen Global hydrological droughts in the 21st century under a changing hydrological regime Earth System Dynamics |
author_facet |
N. Wanders Y. Wada H. A. J. Van Lanen |
author_sort |
N. Wanders |
title |
Global hydrological droughts in the 21st century under a changing hydrological regime |
title_short |
Global hydrological droughts in the 21st century under a changing hydrological regime |
title_full |
Global hydrological droughts in the 21st century under a changing hydrological regime |
title_fullStr |
Global hydrological droughts in the 21st century under a changing hydrological regime |
title_full_unstemmed |
Global hydrological droughts in the 21st century under a changing hydrological regime |
title_sort |
global hydrological droughts in the 21st century under a changing hydrological regime |
publisher |
Copernicus Publications |
series |
Earth System Dynamics |
issn |
2190-4979 2190-4987 |
publishDate |
2015-01-01 |
description |
Climate change very likely impacts future hydrological drought
characteristics across the world. Here, we quantify the impact of
climate change on future low flows and associated hydrological
drought characteristics on a global scale using an alternative
drought identification approach that considers adaptation to future
changes in hydrological regime. The global hydrological model
PCR-GLOBWB was used to simulate daily discharge at 0.5°
globally for 1971–2099. The model was forced with CMIP5 climate
projections taken from five global circulation models (GCMs) and four emission scenarios (representative concentration pathways, RCPs),
from the Inter-Sectoral Impact Model Intercomparison Project.
<br><br>
Drought events occur when discharge is below a threshold. The
conventional variable threshold (VTM) was calculated by deriving the
threshold from the period 1971–2000. The transient variable
threshold (VTM<sub>t</sub>) is a non-stationary approach,
where the threshold is based on the discharge values of the previous
30 years implying the threshold to vary every year during the 21st
century. The VTM<sub>t</sub> adjusts to gradual changes in
the hydrological regime as response to climate change.
<br><br>
Results show a significant negative trend in the low flow regime
over the 21st century for large parts of South America, southern
Africa, Australia and the Mediterranean. In 40–52% of the
world reduced low flows are projected, while increased low flows are
found in the snow-dominated climates.
<br><br>
In 27% of the global area both the drought duration and the
deficit volume are expected to increase when applying the
VTM<sub>t</sub>. However, this area will significantly
increase to 62% when the VTM is applied. The mean global area
in drought, with the VTM<sub>t</sub>, remains rather
constant (11.7 to 13.4%), compared to the substantial
increase when the VTM is applied (11.7 to 20%).
<br><br>
The study illustrates that an alternative drought identification
that considers adaptation to an altered hydrological regime has
a substantial influence on future hydrological drought characteristics. |
url |
http://www.earth-syst-dynam.net/6/1/2015/esd-6-1-2015.pdf |
work_keys_str_mv |
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