Unraveling the significance of soil organic carbon-gravel parameterization: Insights into soil water and heat transport on the Tibetan Plateau

In the Tibetan Plateau (TP) soil water and heat transfer process, soil organic carbon (SOC) and gravel content are considered as the most influential soil texture factors. However, the issues of underestimating SOC and neglecting gravel effect affected the simulation performance of CLM5.0 on soil moisture (SM) and soil temperature (ST). This paper proposed a new parameterization scheme, the organic carbon-gravel (OC-G) scheme, to simulate ST and SM from 1990 to 2018. The results showed that correlation between the simulated and observed ST or SM was higher, and the error was smaller, after the modification of the parameterization scheme. This improvement justifies the applicability of the scheme for soil hydrothermal simulations on the TP. The experiment described that ST and SM were more sensitive to changes in SOC content. And changes in gravel or SOC content had the Same-Frequency effect in the northeast and southeast TP. When the SOC and gravel content changed at the same time, the effects on ST and SM were a cumulative effect. The change directly affected the memory time of ST and SM in summer. Specifically, when the SOC content was increased, the memory time of SM increased in the northwest and decreased in the southeast. When gravel content was increased, the memory time of SM decreased in the northwest but increased in the southeast, but the memory time of ST remained largely unchanged. Changes to the abnormal duration may alter summer weather and climate in Eastern China.

Automated summary

This paper proposes a new parameterization scheme, the organic carbon-gravel (OC-G) scheme, to simulate soil temperature and soil moisture on the Tibetan Plateau. The results show that after modifying the parameterization scheme, the correlation between the simulated and observed values is higher and the error is smaller. The experiment also finds that changes in soil organic carbon and gravel content have significant effects on soil temperature and moisture, with a cumulative effect when both change simultaneously, potentially altering summer weather and climate in Eastern China.