A hydrological model for root zone water storage simulation on a global scale

Abstract

The soil water stored in the root zone is a critical variable for many applications as it plays a key role in several hydrological and atmospheric processes. Many studies have been done to obtain reliable soil water information in the root zone layer. However, most of them are mainly focused on the soil moisture in a certain depth rather than the water stored in the entire rooting system. In this work, a hydrological model is developed to simulate the root zone water storage (RZWS) on a global scale. The model is based on a well validated lumped model and has been extended now to a distribution model. To 5 reflect the natural spatial heterogeneity of the plant rooting system across the world, a key variable that influencing the RZWS, i.e. root zone storage capacity (RZSC), is integrated into the model. The newly developed model is evaluated on runoff and RZWS simulation across ten major basins. The evaluation of runoff indicates the strong capacity of the model for monthly simulation with a good performance on time series and distribution depiction. Results also show the ability of the model for RZWS dynamics mimicing in most of the regions. This model may offer benefits for many applications due to its ability for 10 RZWS simulation. However, attentions need to also be paid for application as the high latitude regions are not investigated by this work due to the incomplete latitudinal coverage of the RZSC. Therefore, the performance of the model in such regions is not justified.

Multisource remote sensing data facilitate ecohydrological simulations without runoff calibration

“…Groundwater is an important part of water resources. Root‐zone water storage represents the reservoir of the plant available water, which will limit the vegetation growth and mediate numerous underground processes to a great extent (Mao & Liu, 2019). They are very important in the water cycle, but it is extremely challenging to monitor and simulate them due to the complexity of underground areas and related cost issues, especially in highly heterogeneous karst regions (Huang et al, 2019; Liu & Sun, 2020).…”

Review

“…• P6L27 "no information is available at the global scale": Please consider including a few more lines describing the issues related to capillary rise modelling in global scale models and include related references, such as (Vergnes, Decharme, and Habets 2014) and references within.…”

“…• P8L28, "it has been well-justified (de Boer-Euser et al, 2019)": please consider specifying what is justified and add other relevant sources, e.g. "the method has been shown to increase model performance at both basin and global scale (e.g., de Boer-Euser et al, 2016, 2019, Gao et al 2014, Wang-Erlandsson et al, 2016, Nijzink et al, 2016".…”