Impact of Lateral Terrestrial Water Flow on Land‐Atmosphere Interactions in the Heihe River Basin in China: Fully Coupled Modeling and Precipitation Recycling Analysis

Abstract

Lateral terrestrial water flow is usually not considered in regional climate modeling. This study focuses on the impact of increased hydrological model complexity for the description of the land-atmosphere interactions in a complex terrain region. For this purpose, we apply the Weather Research and Forecasting (WRF) model with its hydrological modeling extension package WRF-Hydro for the case of the Heihe River Basin in convection permitting atmospheric resolution (3 km). The Heihe River Basin (143,200 km 2 ) is an arid-semiarid inland river basin in Northwestern China. By comparing model simulations results with and without coupling for the period 2008-2010, the effect of lateral terrestrial water flow on land-atmosphere interactions is evaluated with a joint atmospheric-terrestrial water budget analysis, a regional precipitation recycling analysis and a fully three-dimensional atmospheric moisture tracing method (evaporation tagging). The coupled modeling system WRF-Hydro simulates near-surface temperature and precipitation variability similar to the WRF model and demonstrates, in addition, its ability to reproduce daily streamflow. In the fully coupled mode, as a consequence of lateral terrestrial water flow description, the redistribution of infiltration excess in the mountainous area produces higher soil moisture content in the root zone, increases the terrestrial water storage and evapotranspiration, and decreases the total runoff. The resulting wetting and cooling in the near surface affects the regional climate by changing the regional water vapor transports and water vapor content, while, in turn, inducing precipitation differences. Overall, the fully coupled modeling increases the recycling rate, indicating that lateral terrestrial water flow influences regional climate in our study area.With the increase of computational resources in high-resolution Earth System Models, the role of land surface spatial variability on modeling results is more and more emphasized (Clark et al., 2015;Gao et al., 2008).

A Joint Soil‐Vegetation‐Atmospheric Water Tagging Procedure With WRF‐Hydro: Implementation and Application to the Case of Precipitation Partitioning in the Upper Danube River Basin

“…As a side note, the fact that the annual surface evaporation is slightly higher in WRF-Hydro (see section 3.2, and also Senatore et al, 2015, Arnault et al, 2018, Rummler et al, 2019, Zhang et al, 2019 is considered to be related to the primary increasing effect on E tagged , and the relatively high frequency of precipitation events in the study region which masks the secondary decreasing effect on E tagged .…”

“…Annually, WRF overestimates E OBS by 2.7 mm/year (+0.6%) and WRF-Hydro by 7.3 mm/year (+1.5%). The slight increase in surface evaporation induced by WRF-Hydro is the consequence of ponded water infiltration, which increases the soil water storage, as discussed by, for example, Senatore et al (2015), Arnault et al (2018), Rummler et al (2019), and Zhang et al (2019).…”

“…Recent studies showed that considering the horizontal transport of terrestrial water in a climate model has an impact on precipitation (e.g., Arnault, Wagner, et al, ; Arnault et al, ; Kerandi et al, ; Larsen et al, ; Maxwell et al, ; Rahman et al, ; Rummler et al, ; Senatore et al, ; Wagner et al, ; Zhang et al ). Indeed, spatially redistributing soil moisture modifies surface fluxes, which potentially affects boundary layer dynamics, convection initiation and precipitation (e.g., Pielke, ).…”

“…Potential LSM improvements can be reached by enhancing the description of physical processes (e.g., Niu et al, 2011), as well as by refining the soil feature and land use information (e.g., Gao et al, 2008). Wagner et al, 2016;Zhang et al 2019). Indeed, spatially redistributing soil moisture modifies surface fluxes, which potentially affects boundary layer dynamics, convection initiation and precipitation (e.g., Pielke, 2001).…”

Simulation of extreme rainfall and streamflow events in small Mediterranean watersheds with a one-way coupled atmospheric-hydrologic modelling system

“…As summarized by (Rummler et al, 2019), WRF-Hydro is mainly used in its uncoupled mode for model calibration and flood forecasting (e.g., Lahmers et al, 2019;Maidment, 2017;Silver et al, 2017;Verri et al, 2017;Givati et al, 2016;Yucel et al, 2015). Conversely, the fully-coupled mode is usually adopted to investigate land-atmosphere feedbacks (Arnault et al, 2016(Arnault et al, , 2019Rummler et al, 2019;Senatore et al, 2015;Wehbe et al, 2019;Zhang et al, 2019).…”