TY  - JOUR
A1  - He, Zhihua
A1  - Unger-Shayesteh, Katy
A1  - Vorogushyn, Sergiy
A1  - Weise, Stephan M.
A1  - Kalashnikova, Olga
A1  - Gafurov, Abror
A1  - Duethmann, Doris
A1  - Barandun, Martina
A1  - Merz, Bruno
T1  - Constraining hydrological model parameters using water isotopic compositions in a glacierized basin, Central Asia
JF  - Journal of hydrology
N2  - Water stable isotope signatures can provide valuable insights into the catchment internal runoff processes. However, the ability of the water isotope data to constrain the internal apportionments of runoff components in hydrological models for glacierized basins is not well understood. This study developed an approach to simultaneously model the water stable isotopic compositions and runoff processes in a glacierized basin in Central Asia. The fractionation and mixing processes of water stable isotopes in and from the various water sources were integrated into a glacio-hydrological model. The model parameters were calibrated on discharge, snow cover and glacier mass balance data, and additionally isotopic composition of streamflow. We investigated the value of water isotopic compositions for the calibration of model parameters, in comparison to calibration methods without using such measurements. Results indicate that: (1) The proposed isotope-hydrological integrated modeling approach was able to reproduce the isotopic composition of streamflow, and improved the model performance in the evaluation period; (2) Involving water isotopic composition for model calibration reduced the model parameter uncertainty, and helped to reduce the uncertainty in the quantification of runoff components; (3) The isotope-hydrological integrated modeling approach quantified the contributions of runoff components comparably to a three-component tracer-based end-member mixing analysis method for summer peak flows, and required less water tracer data. Our findings demonstrate the value of water isotopic compositions to improve the quantification of runoff components using hydrological models in glacierized basins.
KW  - Water stable isotope
KW  - Isotope-hydrological integrated modeling
KW  - Quantification of runoff components
KW  - Glacierized basins
Y1  - 2019
U6  - https://doi.org/10.1016/j.jhydrol.2019.01.048
SN  - 0022-1694
SN  - 1879-2707
VL  - 571
SP  - 332
EP  - 348
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Duethmann, Doris
A1  - Bolch, Tobias
A1  - Farinotti, Daniel
A1  - Kriegel, David
A1  - Vorogushyn, Sergiy
A1  - Merz, Bruno
A1  - Pieczonka, Tino
A1  - Jiang, Tong
A1  - Su, Buda
A1  - Güntner, Andreas
T1  - Attribution of streamflow trends in snow and glacier melt-dominated catchments of the Tarim River, Central Asia
JF  - Water resources research
N2  - Observed streamflow of headwater catchments of the Tarim River (Central Asia) increased by about 30% over the period 1957-2004. This study aims at assessing to which extent these streamflow trends can be attributed to changes in air temperature or precipitation. The analysis includes a data-based approach using multiple linear regression and a simulation-based approach using a hydrological model. The hydrological model considers changes in both glacier area and surface elevation. It was calibrated using a multiobjective optimization algorithm with calibration criteria based on glacier mass balance and daily and interannual variations of discharge. The individual contributions to the overall streamflow trends from changes in glacier geometry, temperature, and precipitation were assessed using simulation experiments with a constant glacier geometry and with detrended temperature and precipitation time series. The results showed that the observed changes in streamflow were consistent with the changes in temperature and precipitation. In the Sari-Djaz catchment, increasing temperatures and related increase of glacier melt were identified as the dominant driver, while in the Kakshaal catchment, both increasing temperatures and increasing precipitation played a major role. Comparing the two approaches, an advantage of the simulation-based approach is the fact that it is based on process-based relationships implemented in the hydrological model instead of statistical links in the regression model. However, data-based approaches are less affected by model parameter and structural uncertainties and typically fast to apply. A complementary application of both approaches is recommended.
KW  - trend analysis
KW  - data-based
KW  - simulation-based
KW  - multiobjective calibration
KW  - hydrological modeling
KW  - glacier melt
Y1  - 2015
U6  - https://doi.org/10.1002/2014WR016716
SN  - 0043-1397
SN  - 1944-7973
VL  - 51
IS  - 6
SP  - 4727
EP  - 4750
PB  - American Geophysical Union
CY  - Washington
ER  -