Disentangling the impact of event‐ and annual‐scale precipitation extremes on critical‐zone hydrology in semiarid loess vegetated by apple trees

Xiaodong Gao, Hua Wan, Yijian Zeng, Xiaoya Shao, Wei Hu, Luca Brocca, Min Yang, Pute Wu, Xining Zhao*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)
60 Downloads (Pure)

Abstract

The extent and mechanisms by which precipitation extremes affect hydrological processes in the critical zone (CZ) of loess possessing a thick unsaturated zone remains poorly understood. To this end, we here employed a coupled liquid‒vapor‒heat‒airflow STEMMUS (simultaneous transfer of energy, mass, and momentum in unsaturated soil) model to investigate the impact of extreme precipitation, at both event and annual scales, on CZ hydrological processes within a semiarid loess site vegetated by apple trees on China’s Loess Plateau. At the event scale, the vapor flux was two orders of magnitude lower than the liquid water flux. However, the thermal vapor flux penetrated to depths of 200 cm, whereas the isothermal liquid water flux only infiltrated to 100 cm during the study period, implying that thermal-gradient-driven vapor transfer is an important mechanism for deep-layer recharge (DLR). At the annual scale, the DLR below 200 cm during extremely wet years was 6.5 times larger than that during extremely dry years. In contrast, extreme changes in climate had only limited impacts on evapotranspiration; the difference between extremely wet and extremely dry years averaged only 35 mm, much less than the difference in precipitation, which averaged 310 mm. However, the extremely dry years showed a higher ratio (0.58) between transpiration and evapotranspiration than did the extremely wet years (0.51). The findings reported here improve our understanding of CZ hydrological processes related to precipitation extremes in semiarid loess regions.
Original languageEnglish
Article numbere2022WR033042
JournalWater resources research
Volume59
Issue number3
DOIs
Publication statusPublished - 1 Mar 2023

Keywords

  • ITC-ISI-JOURNAL-ARTICLE
  • 2023 OA procedure

Fingerprint

Dive into the research topics of 'Disentangling the impact of event‐ and annual‐scale precipitation extremes on critical‐zone hydrology in semiarid loess vegetated by apple trees'. Together they form a unique fingerprint.

Cite this