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Assessing glacier retreat and its impact on water resources in a headwater of Yangtze River based on CMIP6 projections

Gao, Hongkai ; Feng, Zijing ; Zhang, Tong ; Wang, Yuzhe ; He, Xiaobo ; Li, Hong ; Pan, Xicai ; Ren, Ze ; Chen, Xi and Zhang, Wenxin LU orcid , et al. (2021) In Science of the Total Environment 765.
Abstract

Glacier retreat caused by global warming alters the hydrological regime and poses far-reaching challenges to water resources and nature conservation of the headwater of Yangtze River, and its vast downstream regions with dense population. However, there is still lack of a robust modeling framework of the “climate-glacier-streamflow” in this water tower region, to project the future changes of glacier mass balance, glacier geometry, and the consequent impacts on runoff. Moreover, it is imperative to use the state-of-the-art sixth phase Coupled Model Intercomparison Project (CMIP6) to assess glacio-hydrology variations in future. In this study, we coupled a glacio-hydrological model (FLEXG) with a glacier retreat method... (More)

Glacier retreat caused by global warming alters the hydrological regime and poses far-reaching challenges to water resources and nature conservation of the headwater of Yangtze River, and its vast downstream regions with dense population. However, there is still lack of a robust modeling framework of the “climate-glacier-streamflow” in this water tower region, to project the future changes of glacier mass balance, glacier geometry, and the consequent impacts on runoff. Moreover, it is imperative to use the state-of-the-art sixth phase Coupled Model Intercomparison Project (CMIP6) to assess glacio-hydrology variations in future. In this study, we coupled a glacio-hydrological model (FLEXG) with a glacier retreat method (Δh-parameterization) to simulate glacio-hydrological processes in the Dongkemadi Glacier (over 5155 m.a.s.l), which has the longest continuous glacio-hydrology observation on the headwater of Yangtze River. The FLEXG-Δh model was forced with in-situ observed meteorological data, radar ice thickness, remote sensing topography and land cover data, and validated by measured runoff. The results showed that the model was capable to simulate hydrological processes in this glacierized basin, with Kling-Gupta efficiency (IKGE) of daily runoff simulation 0.88 in calibration and 0.70 in validation. Then, forcing by the bias-corrected meteorological forcing from the eight latest CMIP6 Earth system models under two climate scenarios (RCP2.6 and RCP8.5), we assessed the impact of future climate change on glacier response and its hydrological effects. The results showed that, to the end of simulation in 2100, the volume of the Dongkemadi Glacier would continuously retreat. For the RCP2.6 and RCP8.5 scenarios, the glacier volume will decrease by 8.7 × 108 m3 (74%) and 10.8 × 108 m3 (92%) respectively in 2100. The glacier runoff will increase and reach to peak water around 2060 to 2085, after this tipping point water resources will likely decrease.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Climate change, CMIP6, FLEX-Δh, Glacier retreat, Tibetan Plateau, Yangtze River
in
Science of the Total Environment
volume
765
article number
142774
publisher
Elsevier
external identifiers
  • scopus:85093690763
  • pmid:33572035
ISSN
0048-9697
DOI
10.1016/j.scitotenv.2020.142774
language
English
LU publication?
yes
id
90d5fb9d-c9ec-4331-af46-45a7eb115086
date added to LUP
2020-11-02 00:05:28
date last changed
2024-06-27 00:09:36
@article{90d5fb9d-c9ec-4331-af46-45a7eb115086,
  abstract     = {{<p>Glacier retreat caused by global warming alters the hydrological regime and poses far-reaching challenges to water resources and nature conservation of the headwater of Yangtze River, and its vast downstream regions with dense population. However, there is still lack of a robust modeling framework of the “climate-glacier-streamflow” in this water tower region, to project the future changes of glacier mass balance, glacier geometry, and the consequent impacts on runoff. Moreover, it is imperative to use the state-of-the-art sixth phase Coupled Model Intercomparison Project (CMIP6) to assess glacio-hydrology variations in future. In this study, we coupled a glacio-hydrological model (FLEX<sup>G</sup>) with a glacier retreat method (Δh-parameterization) to simulate glacio-hydrological processes in the Dongkemadi Glacier (over 5155 m.a.s.l), which has the longest continuous glacio-hydrology observation on the headwater of Yangtze River. The FLEX<sup>G</sup>-Δh model was forced with in-situ observed meteorological data, radar ice thickness, remote sensing topography and land cover data, and validated by measured runoff. The results showed that the model was capable to simulate hydrological processes in this glacierized basin, with Kling-Gupta efficiency (I<sub>KGE</sub>) of daily runoff simulation 0.88 in calibration and 0.70 in validation. Then, forcing by the bias-corrected meteorological forcing from the eight latest CMIP6 Earth system models under two climate scenarios (RCP2.6 and RCP8.5), we assessed the impact of future climate change on glacier response and its hydrological effects. The results showed that, to the end of simulation in 2100, the volume of the Dongkemadi Glacier would continuously retreat. For the RCP2.6 and RCP8.5 scenarios, the glacier volume will decrease by 8.7 × 10<sup>8</sup> m<sup>3</sup> (74%) and 10.8 × 10<sup>8</sup> m<sup>3</sup> (92%) respectively in 2100. The glacier runoff will increase and reach to peak water around 2060 to 2085, after this tipping point water resources will likely decrease.</p>}},
  author       = {{Gao, Hongkai and Feng, Zijing and Zhang, Tong and Wang, Yuzhe and He, Xiaobo and Li, Hong and Pan, Xicai and Ren, Ze and Chen, Xi and Zhang, Wenxin and Duan, Zheng}},
  issn         = {{0048-9697}},
  keywords     = {{Climate change; CMIP6; FLEX-Δh; Glacier retreat; Tibetan Plateau; Yangtze River}},
  language     = {{eng}},
  month        = {{04}},
  publisher    = {{Elsevier}},
  series       = {{Science of the Total Environment}},
  title        = {{Assessing glacier retreat and its impact on water resources in a headwater of Yangtze River based on CMIP6 projections}},
  url          = {{http://dx.doi.org/10.1016/j.scitotenv.2020.142774}},
  doi          = {{10.1016/j.scitotenv.2020.142774}},
  volume       = {{765}},
  year         = {{2021}},
}