07 Jun 2023
 | 07 Jun 2023
Status: a revised version of this preprint is currently under review for the journal HESS.

Seasonal dynamics and spatial patterns of soil moisture in a loess catchment

Shaozhen Liu, Ilja van Meerveld, Yali Zhao, Yunqiang Wang, and James W. Kirchner

Abstract. The spatial patterns and temporal dynamics of soil moisture in loess landscapes are not well understood. In this study, volumetric soil moisture was monitored monthly for 6.5 years at 20 cm intervals between the surface and 500 cm depth at 89 sites across a small (0.43 km2) catchment on the Chinese Loess Plateau. The median soil moisture was computed for each month for each monitoring site as a measure of typical soil moisture conditions. Seasonal changes in soil moisture were mainly concentrated in the shallow (0–100 cm) soil, with a clear seasonal separation between wet conditions in October–March and dry conditions in May–July, even though precipitation is highest in July–August. Soil moisture was higher on northwest-facing slopes, due to increased drying from solar radiation on southeast-facing slopes. This effect of slope aspect was greater between October and March, when the zenith angle of the sun was lower and the aspect-dependent contrast in solar radiation reaching the surface was larger. The wetter, northwest-facing slopes were also characterized by larger annual soil moisture storage changes. Soil texture was nearly uniform across both slopes, and soil moisture was not correlated with the topographic wetness index, suggesting that variations in evapotranspiration dominated the spatial pattern of soil moisture in shallow soils during both wet and dry conditions. Water balance calculations indicate that over 90 % of annual precipitation was seasonally cycled in the soil between 0 and 300 cm, suggesting that only a minor fraction infiltrates to groundwater and becomes streamflow. Our findings may be broadly applicable to loess regions with monsoonal climates, and may have practical implications for catchment-scale hydrologic modeling and the design of soil moisture monitoring networks.

Shaozhen Liu et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on hess-2023-133', Anonymous Referee #1, 10 Jul 2023
  • CC1: 'Comment on hess-2023-133', Yanhui Wang, 13 Jul 2023
  • RC2: 'Comment on hess-2023-133', Kendra Kaiser, 20 Jul 2023

Shaozhen Liu et al.

Shaozhen Liu et al.


Total article views: 661 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
508 132 21 661 5 8
  • HTML: 508
  • PDF: 132
  • XML: 21
  • Total: 661
  • BibTeX: 5
  • EndNote: 8
Views and downloads (calculated since 07 Jun 2023)
Cumulative views and downloads (calculated since 07 Jun 2023)

Viewed (geographical distribution)

Total article views: 636 (including HTML, PDF, and XML) Thereof 636 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 28 Sep 2023
Short summary
We study the seasonal and spatial patterns of soil moisture in 0–500 cm soil using 89 monitoring sites in a loess catchment with a monsoonal climate. Seasonal changes in soil moisture were mainly concentrated in the shallow soils, with clear separation between wet and dry conditions. Shallow soil moisture varied with aspect, reflecting spatial variations in evapotranspiration under both wet and dry conditions. Most of the precipitation was seasonally cycled in the soil between 0–300 cm.