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

2019 ◽  
Author(s):  
Ganquan Mao ◽  
Junguo Liu
Keyword(s):  
Soil Water ◽  
Hydrological Model ◽  
Storage Capacity ◽  
Root Zone ◽  
Water Storage ◽  
Global Scale ◽  
Distribution Model ◽  
Lumped Model ◽  
Zone Water ◽  
Strong Capacity

Abstract. The soil water stored in the root zone is a critical variable for many applications as it plays 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 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 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 are not justified.

scholarly journals WAYS v1: a hydrological model for root zone water storage simulation on a global scale

2019 ◽  
Vol 12 (12) ◽  
pp. 5267-5289 ◽  
Author(s):  
Ganquan Mao ◽  
Junguo Liu
Keyword(s):  
Spatial Heterogeneity ◽  
Soil Water ◽  
Regional Differences ◽  
Hydrological Model ◽  
Root Zone ◽  
Water Storage ◽  
Global Scale ◽  
Distribution Model ◽  
Lumped Model ◽  
Zone Water

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 conducted to obtain reliable information on soil water in the root zone layer. However, most of them are mainly focused on the soil moisture within a certain depth rather than the water stored in the entire rooting system. In this work, a hydrological model named the Water And ecosYstem Simulator (WAYS) 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 now been extended to a distribution model. To reflect the natural spatial heterogeneity of the plant rooting system across the world, a key variable that influences RZWS, i.e., root zone storage capacity (RZSC), is integrated into the model. The newly developed model is first evaluated based on runoff and RZWS simulations across 10 major basins. The results show the ability of the model to mimic RZWS dynamics in most of the regions through comparison with proxy data, the normalized difference infrared index (NDII). The model is further evaluated against station observations, including flux tower and gauge data. Despite regional differences, generally good performance is found for both the evaporation and discharge simulations. Compared to existing hydrological models, WAYS's ability to resolve the field-scale spatial heterogeneity of RZSC and simulate RZWS may offer benefits for many applications, e.g., agriculture and land–vegetation–climate interaction investigations. However, the results from this study suggest an additional evaluation of RZWS is required for the regions where the NDII might not be the correct proxy.

scholarly journals Plants as sensors: vegetation response to rainfall predicts root-zone water storage capacity in Mediterranean-type climates

2020 ◽  
Vol 15 (10) ◽  
pp. 104074
Author(s):  
David N Dralle ◽  
W Jesse Hahm ◽  
Daniella M Rempe ◽  
Nathaniel Karst ◽  
Leander D L Anderegg ◽  
...  
Keyword(s):  
Storage Capacity ◽  
Root Zone ◽  
Water Storage ◽  
Vegetation Response ◽  
Water Storage Capacity ◽  
Zone Water

scholarly journals Technical note: Accounting for snow in the estimation of root-zone water storage capacity from precipitation and evapotranspiration fluxes

2020 ◽  
Author(s):  
David N. Dralle ◽  
W. Jesse Hahm ◽  
K. Dana Chadwick ◽  
Erica McCormick ◽  
Daniella M. Rempe
Keyword(s):  
Sierra Nevada ◽  
Hydrological Modeling ◽  
Storage Capacity ◽  
Root Zone ◽  
Water Storage ◽  
Original Method ◽  
Technical Note ◽  
Simple Extension ◽  
Water Storage Capacity ◽  
Zone Water

Abstract. A common parameter in hydrological modeling frameworks is root-zone water storage capacity (SR[L]), which mediates plant-water availability during dry periods and the partitioning of rainfall between runoff and evapotranspiration. Recently, a simple flux-tracking based approach was introduced to estimate the value of SR (Wang-Erlandsson et al., 2016). Here, we build upon this original method, which we argue may overestimate SR in snow-dominated catchments due to snow melt and evaporation processes. We propose a simple extension to the method presented by Wang-Erlandsson et al. (2016), and show that the approach provides a more conservative minimum estimate of SR in snow-dominated watersheds. This SR dataset is available at 1 km resolution for the continental United States, along with the full analysis code, on Google Colaboratory and Earth Engine platforms. We highlight differences between the original and new methods across the rain-snow transition in the Southern Sierra Nevada, California, USA. As climate warms and precipitation increasingly arrives as rain instead of snow, the subsurface may be an increasingly important reservoir for storing plant-available water between wet and dry seasons; improved estimates of SR will therefore better clarify the future role of the subsurface as a storage reservoir that can sustain forests during seasonal dry periods and episodic drought.

scholarly journals Technical note: Accounting for snow in the estimation of root zone water storage capacity from precipitation and evapotranspiration fluxes

2021 ◽  
Vol 25 (5) ◽  
pp. 2861-2867
Author(s):  
David N. Dralle ◽  
W. Jesse Hahm ◽  
K. Dana Chadwick ◽  
Erica McCormick ◽  
Daniella M. Rempe
Keyword(s):  
Sierra Nevada ◽  
Hydrological Modeling ◽  
Storage Capacity ◽  
Root Zone ◽  
Water Storage ◽  
Original Method ◽  
Technical Note ◽  
Simple Extension ◽  
Water Storage Capacity ◽  
Zone Water

Abstract. A common parameter in hydrological modeling frameworks is root zone water storage capacity (SR[L]), which mediates plant water availability during dry periods as well as the partitioning of rainfall between runoff and evapotranspiration. Recently, a simple flux-tracking-based approach was introduced to estimate the value of SR (Wang-Erlandsson et al., 2016). Here, we build upon this original method, which we argue may overestimate SR in snow-dominated catchments due to snow melt and evaporation processes. We propose a simple extension to the method presented by Wang-Erlandsson et al. (2016) and show that the approach provides a lower estimate of SR in snow-dominated watersheds. This SR dataset is available at a 1 km resolution for the continental USA, along with the full analysis code, on the Google Colab and Earth Engine platforms. We highlight differences between the original and new methods across the rain–snow transition in the Southern Sierra Nevada, California, USA. As climate warms and precipitation increasingly arrives as rain instead of snow, the subsurface may be an increasingly important reservoir for storing plant-available water between wet and dry seasons; therefore, improved estimates of SR will better clarify the future role of the subsurface as a storage reservoir that can sustain forests during seasonal dry periods and episodic drought.

A decreasing trend in global soil water storage from 1981 to 2017

2021 ◽  
Author(s):  
XinRui Luo ◽  
Shaoda Li ◽  
Wunian Yang ◽  
Liang Liu ◽  
Xiaolu Tang
Keyword(s):  
Soil Water ◽  
Water Loss ◽  
Root Zone ◽  
Carbon Sink ◽  
Temporal Trends ◽  
Water Storage ◽  
Terrestrial Ecosystems ◽  
Environmental Drivers ◽  
Soil Water Storage ◽  
Soil Drought

<p>Soil water storage serves as a vital resource of the terrestrial ecosystems, and it can significantly influence water cycle and carbon cycling with the frequent occurrence of soil drought induced by land-atmosphere feedbacks. However, there are high variations and uncertainties of root zone soil water storage. This study applied comparison map profile (CMP), Mann-Kendall test, Theil-Sen estimate and partial correlation analysis to (1) estimate the global root zone (0~1 m) soil water storage, (2) and investigate the spatial and temporal patterns from 1981 to 2017 at the global scale, (3) and their relationships with environmental drivers (precipitation, temperature, potential evaportranspiration) using three soil moisture (SM) products – ERA-5, GLDAS and MERRA-2. Globally, the average annual soil water storage from 1981 to 2017 varied significantly, ranging from 138.3 (100 Pg a<sup>-1</sup>, 1 Pg = 10<sup>15</sup> g) in GLDAS to 342.6 (100 Pg a<sup>-1</sup>) in ERA-5. Soil water storage of the three SM products consistently showed a decreasing trend. However, the temporal trend of soil water storage among different climate zones was different, showing a decreasing trend in tropical, temperate and cold zones, but an increasing trend in polar regions. On the other hand, temporal trends in arid regions differed from ERA-5, GLDAS and MERRA-2. Spatially, the SM products differed greatly, particularly for boreal areas with D value higher for 2500 Mg ha<sup>-1</sup> a<sup>-1</sup> and CC value lower for -0.2 between GLDAS and MERRA-2. Over 1981 to 2017, water storage of more than 50% of the global land area suffered from a decreasing trend, especially in Africa and Northeastern of China. Precipitation was the main dominated driver for variation of soil water storage, and distribution varied in different SM products. In conclusion, a global decreasing trend in soil water storage indicate a water loss from soils, and how the water loss affecting carbon sink in terrestrial ecosystems under ongoing climate change needs further investigation.</p>

scholarly journals Effects of Earthworm Cast Application on Water Evaporation and Storage in Loess Soil Column Experiments

2020 ◽  
Vol 12 (8) ◽  
pp. 3112 ◽  
Author(s):  
Yanpei Li ◽  
Mingan Shao ◽  
Jiao Wang ◽  
Tongchuan Li
Keyword(s):  
Soil Water ◽  
Small Particle ◽  
Storage Capacity ◽  
Water Movement ◽  
Soil Column ◽  
Water Storage ◽  
Loess Soil ◽  
Soil Evaporation ◽  
Upward Movement ◽  
Water Storage Capacity

Earthworm cast is a common bio-organic fertiliser, which can effectively improve soil fertility and structure. However, only a few studies have focused on the effect of earthworm cast on soil water movement. In this study, loess soil was used to determine the effects of earthworm cast application on soil evaporation. The effects on water storage capacity and capillary upward movement were also investigated. A laboratory-based soil column experiment using earthworm cast with different particle sizes (1–3 × 1–2 cm and 3–5 × 2–4 cm) and three application doses (5%, 7.5%, and 10%) was carried out. The daily evaporation and volume of capillary ascension were monitored. The addition of earthworm cast clearly affected the soil evaporation by changing soil water storage capacity and capillary water upward movement. Compared with control soil, the application of 5% small-particle cast reduced the soil cumulative evaporation by 5.13%, while the cumulative evaporation was higher in all large-particle cast treatments. The upward capillary water movement increased with increasing dose of earthworm cast, but decreased with increasing particle size. Overall, the addition of earthworm cast clearly enhanced the water storage capacity of the soil, with the small-particle cast having greater effects than the large-particle cast. We concluded that the application of 5% small-particle earthworm cast can enhance soil water retention and reduce soil evaporation.

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