Holy Tree on QuShui, Tibet - Photo by Yongjiu Dai

A new version of the global high-resolution dataset of soil hydraulic and thermal parameters for land surface modeling

Introduction | Data citation | Data download

Introduction

A newly developed global dataset of soil hydraulic and thermal parameters using multiple Pedotransfer Functions (PTFs) that are widely cited or recently developed is provided for Land Surface Modeling.

The dataset consists of two sets of parameters derived respectively from the Global Soil Dataset for Earth System Models (GSDE) [Shangguan et al., 2014] and SoilGrids [Hengl et al., 2014, 2017] databases. The published variables are listed in the table below. These variables are all provided at the spatial resolution of 30" ranging from 90oN to 90oS, 180oW to 180oE, with four sets of vertical profiles available [i.e., as vertical resolutions of SoilGrids (0 - 0.05 m, 0.05 - 0.15 m, 0.15 - 0.30 m, 0.30 - 0.60 m, 0.60 - 1.00 m, and 1.00 - 2.00 m), Noah-LSM (0 - 0.1 m, 0.1 - 0.4 m, 0.4 - 1.0 m, and 1.0 - 2.0 m), JULES (0 - 0.1 m, 0.1 - 0.35 m, 0.35 - 1.0 m, and 1.0 - 3.0 m) and CoLM/CLM (0 - 0.0451 m, 0.0451 - 0.0906 m, 0.0906 - 0.1655 m, 0.1655 - 0.2891 m, 0.2891 - 0.4929 m, 0.4929 - 0.8289 m, 0.8289 - 1.3828 m, 1.3828 - 3.8019 m)]. The dataset is currently stored in the binary format.

The soil water retention parameters, based on the Campbell [1974] and van Genuchten [1980] (hereafter VG) models, are obtained from a fitting method to find the optimal water retention parameters from ensemble PTFs. The soil hydraulic conductivity is estimated as the median values of ensemble PTFs. The heat capacity of soil solids is calculated as the volumetric weighted average of the heat capacity of mineral soils, soil organic matters (SOM) and gravels. And the soil thermal conductivity is estimated following the models of Johansen [1975] and Balland and Arp [2005], with all the effects of soil constituents such as SOM and gravels considered.

The detailed information can be found in the following publications.

Data citation

Dai, Y., N. Wei, H. Yuan, S. Zhang, W. Shangguan, S. Liu, and X. Lu (2019a), Evaluation of soil thermal conductivity schemes for use in land surface modelling, under review in J. Adv. Model. Earth System.

Dai, Y., Q. Xin, N. Wei, Y. Zhang, W. Shangguan, H. Yuan, S. Zhang, S. Liu, and X. Lu (2019b), A global high-resolution dataset of soil hydraulic and thermal properties for land surface modeling, J. Adv. Model. Earth System, accepted.

Data download

The parameters derived from the GSDE can be downloaded currently in the following table, and those from SoilGrids will be published soon after the space for data storage is enlarged on our server.

No. Attributes Units Data for CoLM/CLM Data for SoilGrids Data for JULES Data for Noah-LSM
1. Volumetric fraction of gravels cm3 cm-3 vf_gravels_s_8L vf_gravels_s_6L vf_gravels_s_4L_Jules vf_gravels_s_4L_Noah
2. Volumetric fraction of SOM cm3 cm-3 vf_om_s_8L vf_om_s_6L vf_om_s_4L_Jules vf_om_s_4L_Noah
3. Volumetric fraction of sand cm3 cm-3 vf_sand_s_8L vf_sand_s_6L vf_sand_s_4L_Jules vf_sand_s_4L_Noah
4. Volumetric fraction of silt cm3 cm-3 vf_silt_s_8L vf_silt_s_6L vf_silt_s_4L_Jules vf_silt_s_4L_Noah
5. Volumetric fraction of clay cm3 cm-3 vf_clay_s_8L vf_clay_s_6L vf_clay_s_4L_Jules vf_clay_s_4L_Noah
6. Volumetric fraction of quartz within mineral soils cm3 cm-3 vf_quartz_mineral_s_8L vf_quartz_mineral_s_6L vf_quartz_mineral_s_4L_Jules vf_quartz_mineral_s_4L_Noah
7. Saturated water content cm3 cm-3 theta_s_8L theta_s_6L theta_s_4L_Jules theta_s_4L_Noah
8. Log-10 transformation of saturated hydraulic conductivity cm day-1 log_k_s_8L log_k_s_6L log_k_s_4L_Jules log_k_s_4L_Noah
9. Saturated suction for the Campbell model cm psi_s_8L psi_s_6L psi_s_4L_Jules psi_s_4L_Noah
10. Pore size distribution index for the Campbell model - lambda_8L lambda_6L lambda_4L_Jules lambda_4L_Noah
11. Residual moisture content for the VG model cm3 cm-3 VGM_theta_r_8L VGM_theta_r_6L VGM_theta_r_4L_Jules VGM_theta_r_4L_Noah
12. The inverse of the air-entry value for the VG model cm-1 VGM_alpha_8L VGM_alpha_6L VGM_alpha_4L_Jules VGM_alpha_4L_Noah
13. Log-10 transformation of a shape parameter for the VG model - log_VGM_n_8L log_VGM_n_6L log_VGM_n_4L_Jules log_VGM_n_4L_Noah
14. Volumetric heat capacity of soil solids in a unit soil volume J m-3 K-1 csol_8L csol_6L csol_4L_Jules csol_4L_Noah
15. Thermal conductivity of unfrozen saturated soils W m-1 K-1 tksatu_8L tksatu_6L tksatu_4L_Jules tksatu_4L_Noah
16. Thermal conductivity of frozen saturated soils W m-1 K-1 tksatf_8L tksatf_6L tksatf_4L_Jules tksatf_4L_Noah
17. Thermal conductivity of dry soils W m-1 K-1 tkdry_8L tkdry_6L tkdry_4L_Jules tkdry_4L_Noah