Long-term soil moisture dynamics derived from GNSS interferometric reflectometry: a case study for Sutherland, South Africa

GPS Solutions ◽  
2015 ◽  
Vol 20 (4) ◽  
pp. 641-654 ◽  
Author(s):  
Sibylle Vey ◽  
Andreas Güntner ◽  
Jens Wickert ◽  
Theresa Blume ◽  
Markus Ramatschi
Keyword(s):  
South Africa ◽  
Soil Moisture ◽  
Soil Moisture Dynamics ◽  
Moisture Dynamics

scholarly journals Long‐term predictability of soil moisture dynamics at the global scale: Persistence versus large‐scale drivers

2016 ◽  
Vol 43 (16) ◽  
pp. 8554-8562 ◽  
Author(s):  
Nadine Nicolai‐Shaw ◽  
Lukas Gudmundsson ◽  
Martin Hirschi ◽  
Sonia I. Seneviratne
Keyword(s):  
Soil Moisture ◽  
Large Scale ◽  
Global Scale ◽  
Soil Moisture Dynamics ◽  
Moisture Dynamics

scholarly journals Recharge estimation and soil moisture dynamics in a Mediterranean karst aquifer

2014 ◽  
Vol 11 (7) ◽  
pp. 8803-8844 ◽  
Author(s):  
F. Ries ◽  
J. Lange ◽  
S. Schmidt ◽  
H. Puhlmann ◽  
M. Sauter
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Unsaturated Soil ◽  
Soil Depth ◽  
Climatic Gradient ◽  
Soil Moisture Dynamics ◽  
Soil Zone ◽  
Moisture Dynamics ◽  
Hydrus 1D

Abstract. Knowledge of soil moisture dynamics in the unsaturated soil zone provides valuable information on the temporal and spatial variability of groundwater recharge. This is especially true for the Mediterranean region, where a substantial fraction of long-term groundwater recharge is expected to occur during high magnitude precipitation events of above-average wet winters. To elucidate process understanding of infiltration processes during these extreme events, a monitoring network of precipitation gauges, meteorological stations, and soil moisture plots was installed in an area with a steep climatic gradient in the Jordan Valley region. In three soil moisture plots, Hydrus-1D was used to simulate water movement in the unsaturated soil zone with soil hydraulic parameters estimated by the Shuffled Complex Evolution Metropolis algorithm. To generalize our results, we modified soil depth and rainfall input to simulate the effect of the pronounced climatic gradient and soil depth variability on percolation fluxes and applied the calibrated model to a time series with 62 years of meteorological data. Soil moisture measurements showed a pronounced seasonality and suggested rapid infiltration during heavy rainstorms. Hydrus-1D successfully simulated short and long-term soil moisture patterns, with the majority of simulated deep percolation occurring during a few intensive rainfall events. Temperature drops in a nearby groundwater well were observed synchronously with simulated percolation pulses, indicating rapid groundwater recharge mechanisms. The 62 year model run yielded annual percolation fluxes of up to 66% of precipitation depths during wet years and of 0% during dry years. Furthermore, a dependence of recharge on the temporal rainfall distribution could be shown. Strong correlations between depth of recharge and soil depth were also observed.

Impact of diverse tillage on soil moisture dynamics

2012 ◽  
Vol 26 (3) ◽  
pp. 301-309 ◽  
Author(s):  
C. Sławiński ◽  
J. Cymerman ◽  
B. Witkowska-Walczak ◽  
K. Lamorski
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Water Retention ◽  
Reduced Tillage ◽  
Traditional Management ◽  
Soil Moisture Dynamics ◽  
Tillage System ◽  
Moisture Dynamics ◽  
Term Field

Impact of diverse tillage on soil moisture dynamicsThe influences of traditional and reduced tillage on the water content dynamics of two soils were investigated in a long-term field experiment under nearly the same meteorological conditions for a winter wheat monoculture during three years. In addition to the moisture changes, the basic physicochemical properties, water retention, differential porosity and hydraulic conductivity of the investigated soils were measured. The results have shown the dependence between moisture and the tillage system applied for both types of soil. The soil water content was higher under reduced tillage in comparison to traditional management.

scholarly journals Recharge estimation and soil moisture dynamics in a Mediterranean, semi-arid karst region

2015 ◽  
Vol 19 (3) ◽  
pp. 1439-1456 ◽  
Author(s):  
F. Ries ◽  
J. Lange ◽  
S. Schmidt ◽  
H. Puhlmann ◽  
M. Sauter
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Unsaturated Soil ◽  
Soil Depth ◽  
Climatic Gradient ◽  
Soil Moisture Dynamics ◽  
Soil Zone ◽  
Moisture Dynamics ◽  
Hydrus 1D

Abstract. Knowledge of soil moisture dynamics in the unsaturated soil zone provides valuable information on the temporal and spatial variability of groundwater recharge. This is especially true for the Mediterranean region, where a substantial fraction of long-term groundwater recharge is expected to occur during high magnitude precipitation events of above-average wet winters. To elucidate process understanding of infiltration processes during these extreme events, a monitoring network of precipitation gauges, meteorological stations, and soil moisture plots was installed in an area with a steep climatic gradient in the Jordan Valley region. In three soil moisture plots, Hydrus-1D was used to simulate water movement in the unsaturated soil zone with soil hydraulic parameters estimated by the Shuffled Complex Evolution Metropolis algorithm. To generalize our results, we modified soil depth and rainfall input to simulate the effect of the pronounced climatic gradient and soil depth variability on percolation fluxes and applied the calibrated model to a time series with 62 years of meteorological data. Soil moisture measurements showed a pronounced seasonality and suggested rapid infiltration during heavy rainstorms. Hydrus-1D successfully simulated short and long-term soil moisture patterns, with the majority of simulated deep percolation occurring during a few intensive rainfall events. Temperature drops in a nearby groundwater well were observed synchronously with simulated percolation pulses, indicating rapid groundwater recharge mechanisms. The 62-year model run yielded annual percolation fluxes of up to 66% of precipitation depths during wet years and of 0% during dry years. Furthermore, a dependence of recharge on the temporal rainfall distribution could be shown. Strong correlations between depth of recharge and soil depth were also observed.

scholarly journals Evaluating the impacts of environmental factors on soil moisture temporal dynamics at different time scales

2020 ◽  
Author(s):  
Qi Chai ◽  
Tiejun Wang ◽  
Chongli Di
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Time Scales ◽  
Temporal Dynamics ◽  
Soil Moisture Dynamics ◽  
Temporal Variance ◽  
The Impact ◽  
Moisture Dynamics ◽  
Different Time Scales

Abstract Soil moisture displays complex spatiotemporal patterns across scales, making it important to disentangle the impacts of environmental factors on soil moisture temporal dynamics at different time scales. This study evaluated the factors affecting soil moisture dynamics at different time scales using long-term soil moisture data obtained from Nebraska and Utah. The empirical mode decomposition method was employed to decompose soil moisture time series into different temporal components with several intrinsic mode functions (IMFs) and one residual component. Results showed that the percent variance contribution (PVC) of IMFs to the total soil moisture temporal variance tended to increase for the IMFs with longer time periods. It indicated that the long-term soil moisture variations in study regions were mainly determined by low-temporal frequency signals related to seasonal climate and vegetation variations. Besides, the PVCs at short- and medium-temporal ranges were positively correlated with climate dryness, while negatively at longer temporal ranges. Moreover, the results suggested that the impact of climate on soil moisture dynamics at different time scales might vary across different climate zones, while soil effect was comparatively less in both regions. It provides additional insights into understanding soil moisture temporal dynamics in regions with contrasting climatic conditions.

scholarly journals Plot and field scale soil moisture dynamics and subsurface wetness control on runoff generation in a headwater in the Ore Mountains

2010 ◽  
Vol 14 (6) ◽  
pp. 873-889 ◽  
Author(s):  
E. Zehe ◽  
T. Graeff ◽  
M. Morgner ◽  
A. Bauer ◽  
A. Bronstert
Keyword(s):  
Soil Moisture ◽  
Sampling Strategy ◽  
Morphological Parameters ◽  
Antecedent Soil Moisture ◽  
Soil Moisture Dynamics ◽  
Long Term Monitoring ◽  
Grassland Site ◽  
Term Monitoring ◽  
Moisture Dynamics

Abstract. This study presents an application of an innovative sampling strategy to assess soil moisture dynamics in a headwater of the Weißeritz in the German eastern Ore Mountains. A grassland site and a forested site were instrumented with two Spatial TDR clusters (STDR) that consist of 39 and 32 coated TDR probes of 60 cm length. Distributed time series of vertically averaged soil moisture data from both sites/ensembles were analyzed by statistical and geostatistical methods. Spatial variability and the spatial mean at the forested site were larger than at the grassland site. Furthermore, clustering of TDR probes in combination with long-term monitoring allowed identification of average spatial covariance structures at the small field scale for different wetness states. The correlation length of soil water content as well as the sill to nugget ratio at the grassland site increased with increasing average wetness and but, in contrast, were constant at the forested site. As soil properties at both the forested and grassland sites are extremely variable, this suggests that the correlation structure at the forested site is dominated by the pattern of throughfall and interception. We also found a very strong correlation between antecedent soil moisture at the forested site and runoff coefficients of rainfall-runoff events observed at gauge Rehefeld. Antecedent soil moisture at the forest site explains 92% of the variability in the runoff coefficients. By combining these results with a recession analysis we derived a first conceptual model of the dominant runoff mechanisms operating in this catchment. Finally, we employed a physically based hydrological model to shed light on the controls of soil- and plant morphological parameters on soil average soil moisture at the forested site and the grassland site, respectively. A homogeneous soil setup allowed, after fine tuning of plant morphological parameters, most of the time unbiased predictions of the observed average soil conditions observed at both field sites. We conclude that the proposed sampling strategy of clustering TDR probes is suitable to assess unbiased average soil moisture dynamics in critical functional units, in this case the forested site, which is a much better predictor for event scale runoff formation than pre-event discharge. Long term monitoring of such critical landscape elements could maybe yield valuable information for flood warning in headwaters. We thus think that STDR provides a good intersect of the advantages of permanent sampling and spatially highly resolved soil moisture sampling using mobile rods.

scholarly journals Plot and field scale soil moisture dynamics and subsurface wetness control on runoff generation in a headwater in the Ore Mountains

2009 ◽  
Vol 6 (6) ◽  
pp. 7503-7537 ◽  
Author(s):  
E. Zehe ◽  
T. Graeff ◽  
M. Morgner ◽  
A. Bauer ◽  
A. Bronstert
Keyword(s):  
Soil Moisture ◽  
Sampling Strategy ◽  
Runoff Generation ◽  
Field Scale ◽  
Soil Moisture Dynamics ◽  
Long Term Monitoring ◽  
Grassland Site ◽  
Term Monitoring ◽  
Moisture Dynamics

Abstract. This study presents an application of an innovative sampling strategy to assess soil moisture dynamics in a headwater of the Weißeritz in the German eastern Ore Mountains. A grassland site and a forested site were instrumented with two Spatial TDR clusters (STDR) that consist of 39 and 32 coated TDR probes of 60 cm length. Distributed time series of vertically averaged soil moisture data from both sites/ensembles were analyzed by statistical and geostatistical methods. Spatial variability and the spatial mean at the forested site were larger than at the grassland site. Furthermore, clustering of TDR probes in combination with long-term monitoring allowed identification of average spatial covariance structures at the small field scale for different wetness states. The correlation length of soil water content as well as the sill to nugget ratio at the grassland site increased with increasing average wetness and but, in contrast, were constant at the forested site. As soil properties at both the forested and grassland sites are extremely variable, this suggests that the correlation structure at the forested site is dominated by the pattern of throughfall and interception. We also found a strong correlation between average soil moisture dynamics and runoff coefficients of rainfall-runoff events observed at gauge Rehefeld, which explains almost as much variability in the runoff coefficients as pre-event discharge. By combining these results with a recession analysis we derived a first conceptual model of the dominant runoff mechanisms operating in this catchment. Finally, long term simulations with a physically based hydrological model were in good/acceptable accordance with the time series of spatial average soil water content observed at the forested site and the grassland site, respectively. Both simulations used a homogeneous soil setup that closely reproduces observed average soil conditions observed at the field sites. This corroborates the proposed sampling strategy of clustering TDR probes in typical functional units is a promising technique to explore the soil moisture control on runoff generation. Long term monitoring of such sites could maybe yield valuable information for flood warning. The sampling strategy helps furthermore to unravel different types of soil moisture variability.

scholarly journals Evaluating long-term potential evapotranspiration and soil moisture dynamics at Shanghai City China

2021 ◽  
Vol 228 ◽  
pp. 02004
Author(s):  
Manqi Wang
Keyword(s):  
Soil Moisture ◽  
Potential Evapotranspiration ◽  
Dynamic Changes ◽  
Soil Moisture Dynamics ◽  
Temperature And Precipitation ◽  
Flow Transport ◽  
Richard's Equation ◽  
Shanghai City ◽  
Moisture Dynamics

As the finical hub of China, the Shanghai metropolitan area is one of the most important regions on earth, which requires significant efforts in water, energy and resources management and supply. Ongoing dynamic changes in climate have posed large uncertainties in our ability to better quantify, estimate and predict future hydrological and ecological responses, including soil moisture dynamics and potential evapotranspirative demands. Given these significant implications, in this study, we focused on better understanding long-term dynamic trends in soil moisture and potential evapotranspiration at Shanghai with the Hargreaves equation and 1-Dimensional flow transport with Richard’s equation. We further tested how perturbations in temperature and precipitation patterns influence soil moisture and potential evapotranspiration responses. Our results suggested significant correlation between temperature and potential evapotranspiration as well as precipitation inputs and soil moisture. We believe these results can provide useful insights to help us better understand the hydrological responses at Shanghai to climate change.

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