Climate Change Impacts on the Upper Indus Hydrology: Sources, Shifts and Extremes.

Autor: Lutz AF; FutureWater, Costerweg 1V, 6702 AA, Wageningen, The Netherlands.; Utrecht University, Department of Physical Geography, PO Box 80115, 3508 TC, Utrecht, The Netherlands., Immerzeel WW; FutureWater, Costerweg 1V, 6702 AA, Wageningen, The Netherlands.; Utrecht University, Department of Physical Geography, PO Box 80115, 3508 TC, Utrecht, The Netherlands., Kraaijenbrink PD; Utrecht University, Department of Physical Geography, PO Box 80115, 3508 TC, Utrecht, The Netherlands., Shrestha AB; International Centre for Integrated Mountain Development, GPO Box 3226, Khumaltar, Kathmandu, Nepal., Bierkens MF; Utrecht University, Department of Physical Geography, PO Box 80115, 3508 TC, Utrecht, The Netherlands.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2016 Nov 09; Vol. 11 (11), pp. e0165630. Date of Electronic Publication: 2016 Nov 09 (Print Publication: 2016).
DOI: 10.1371/journal.pone.0165630
Abstrakt: The Indus basin heavily depends on its upstream mountainous part for the downstream supply of water while downstream demands are high. Since downstream demands will likely continue to increase, accurate hydrological projections for the future supply are important. We use an ensemble of statistically downscaled CMIP5 General Circulation Model outputs for RCP4.5 and RCP8.5 to force a cryospheric-hydrological model and generate transient hydrological projections for the entire 21st century for the upper Indus basin. Three methodological advances are introduced: (i) A new precipitation dataset that corrects for the underestimation of high-altitude precipitation is used. (ii) The model is calibrated using data on river runoff, snow cover and geodetic glacier mass balance. (iii) An advanced statistical downscaling technique is used that accounts for changes in precipitation extremes. The analysis of the results focuses on changes in sources of runoff, seasonality and hydrological extremes. We conclude that the future of the upper Indus basin's water availability is highly uncertain in the long run, mainly due to the large spread in the future precipitation projections. Despite large uncertainties in the future climate and long-term water availability, basin-wide patterns and trends of seasonal shifts in water availability are consistent across climate change scenarios. Most prominent is the attenuation of the annual hydrograph and shift from summer peak flow towards the other seasons for most ensemble members. In addition there are distinct spatial patterns in the response that relate to monsoon influence and the importance of meltwater. Analysis of future hydrological extremes reveals that increases in intensity and frequency of extreme discharges are very likely for most of the upper Indus basin and most ensemble members.
Competing Interests: We have read the journal's policy and the authors of this manuscript have the following competing interests: AFL and WWI are employed by FutureWater. There are no patents, products in development or marketed products to declare. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials.
Databáze: MEDLINE
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