SOIL-WATERGRIDS, mapping dynamic changes in soil moisture and depth of water table from 1970 to 2014

AbstractWe introduce here SOIL-WATERGRIDS, a new dataset of dynamic changes in soil moisture and depth of water table over 45 years from 1970 to 2014 globally resolved at 0.25 × 0.25 degree resolution (about 30 × 30 km at the equator) along a 56 m deep soil profile. SOIL-WATERGRIDS estimates were obtained using the BRTSim model instructed with globally gridded soil physical and hydraulic properties, land cover and use characteristics, and hydrometeorological variables to account for precipitation, ecosystem-specific evapotranspiration, snowmelt, surface runoff, and irrigation. We validate our estimates against independent observations and re-analyses of the soil moisture, water table depth, wetland occurrence, and runoff. SOIL-WATERGRIDS brings into a single product the monthly mean water saturation at three depths in the root zone and the depth of the highest and lowest water tables throughout the reference period, their long-term monthly averages, and data quality. SOIL-WATERGRIDS can therefore be used to analyse trends in water availability for agricultural abstraction, assess the water balance under historical weather patterns, and identify water stress in sensitive managed and unmanaged ecosystems.

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Development and application of long-term root zone salt balance model for predicting soil salinity in arid shallow water table area

Agricultural Water Management ◽

10.1016/j.agwat.2018.10.043 ◽

2019 ◽

Vol 213 ◽

pp. 486-498 ◽

Cited By ~ 8

Author(s):

Guanfang Sun ◽

Yan Zhu ◽

Ming Ye ◽

Jinzhong Yang ◽

Zhongyi Qu ◽

...

Keyword(s):

Shallow Water ◽

Water Table ◽

Soil Salinity ◽

Root Zone ◽

Balance Model ◽

Salt Balance ◽

Shallow Water Table

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Effects of Long-Term Vegetation Restoration on Distribution of Deep Soil Moisture in Semi-arid Northwest of China

Journal of soil science and plant nutrition ◽

10.1007/s42729-020-00280-4 ◽

2020 ◽

Vol 20 (4) ◽

pp. 2123-2132

Author(s):

Limei Wang ◽

Aisheng Ma ◽

Hong Zhang ◽

Jianguo Zhang ◽

Qiang Dong ◽

...

Keyword(s):

Soil Moisture ◽

Vegetation Restoration ◽

Deep Soil ◽

Semi Arid

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A global analysis of satellite derived and DGVM surface soil moisture products

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-8-4281-2011 ◽

2011 ◽

Vol 8 (2) ◽

pp. 4281-4312

Author(s):

K. T. Rebel ◽

R. A. M. de Jeu ◽

P. Ciais ◽

N. Viovy ◽

S. L. Piao ◽

...

Keyword(s):

Soil Moisture ◽

Land Surface ◽

Root Zone ◽

Global Analysis ◽

Single Layer ◽

Global Scale ◽

Rain Event ◽

Deep Soil ◽

Surface Climate ◽

Soil Moisture Availability

Abstract. Soil moisture availability is important in regulating photosynthesis and controlling land surface-climate feedbacks at both the local and global scale. Recently, global remote-sensing datasets for soil moisture have become available. In this paper we assess the possibility of using remotely sensed soil moisture (AMSR-E) to evaluate the results of the process-based vegetation model ORCHIDEE during the period 2003–2004. We find that the soil moisture products of AMSR-E and ORCHIDEE correlate well, in particular when considering the root zone soil moisture of ORCHIDEE. However, the root zone soil moisture in ORCHIDEE consistently overestimated the temporal autocorrelation relative to AMSR-E and in situ measurements. This may be due to the different vertical depth of the two products, to the uncertainty in precipitation forcing in ORCHIDEE, and to the fact that the structure of ORCHIDEE consisting of a single-layer deep soil, does not allow simulation of the proper cascade of time scales that characterize soil drying after each rain event. We conclude that assimilating soil moisture in ORCHIDEE using AMSR-E with the current hydrological model may significantly improve the soil moisture dynamics in ORCHIDEE.

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Quantifying Long-Term Land Surface and Root Zone Soil Moisture over Tibetan Plateau

Remote Sensing ◽

10.3390/rs12030509 ◽

2020 ◽

Vol 12 (3) ◽

pp. 509 ◽

Cited By ~ 6

Author(s):

Ruodan Zhuang ◽

Yijian Zeng ◽

Salvatore Manfreda ◽

Zhongbo Su

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Land Surface ◽

Root Zone ◽

Cumulative Distribution ◽

Analytical Relationship ◽

The Tibetan Plateau ◽

Climate Systems

It is crucial to monitor the dynamics of soil moisture over the Tibetan Plateau, while considering its important role in understanding the land-atmosphere interactions and their influences on climate systems (e.g., Eastern Asian Summer Monsoon). However, it is very challenging to have both the surface and root zone soil moisture (SSM and RZSM) over this area, especially the study of feedbacks between soil moisture and climate systems requires long-term (e.g., decadal) datasets. In this study, the SSM data from different sources (satellites, land data assimilation, and in-situ measurements) were blended while using triple collocation and least squares method with the constraint of in-situ data climatology. A depth scaling was performed based on the blended SSM product, using Cumulative Distribution Function (CDF) matching approach and simulation with Soil Moisture Analytical Relationship (SMAR) model, to estimate the RZSM. The final product is a set of long-term (~10 yr) consistent SSM and RZSM product. The inter-comparison with other existing SSM and RZSM products demonstrates the credibility of the data blending procedure used in this study and the reliability of the CDF matching method and SMAR model in deriving the RZSM.

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The effects of stemflow on redistributing precipitation and infiltration around shrubs

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2017-0043 ◽

2018 ◽

Vol 66 (1) ◽

pp. 79-86 ◽

Cited By ~ 4

Author(s):

Shengqi Jian ◽

Xueli Zhang ◽

Dong Li ◽

Deng Wang ◽

Zening Wu ◽

...

Keyword(s):

Soil Moisture ◽

Root Zone ◽

Soil Depth ◽

Rainfall Threshold ◽

Chinese Loess Plateau ◽

Wetting Front ◽

Deep Soil ◽

Soil Layers ◽

Chinese Loess ◽

Caragana Korshinskii

Abstract The experiments of stemflow of two semiarid shrubs (Caragana korshinskii and Hippophae rhamnoides) and its effect on soil water enhancement were conducted from 1st May to 30th September of 2009-2013 in the Chinese Loess Plateau. Stemflow values in C. korshinskii and H. rhamnoides averaged 6.7% and 2.4% of total rainfall. The rainfall threshold for stemflow generation was 0.5 and 2.5 mm for C. korshinskii and H. rhamnoides. When rainfall was less than 17.0 mm, the funnelling ratios were highly variable, however, stable funnelling ratios were found for rainfall greater than 17.0 mm for C. korshinskii. The funnelling ratios of H. rhamnoides first increased until a threshold value of 10.0 mm and then the funnelling ratios begin stabilize. The wetting front depths in the area around stem was 1.4-6.7 and 1.3-2.9 times deeper than area outside the canopy for C. korshinskii and H. rhamnoides. Soil moisture at soil depth 0-200 cm was 25.6% and 23.4% higher in soil around stem than that outside canopy for C. korshinskii and H. rhamnoides. The wetting front advanced to depths of 120 and 100 cm in the area around stem and to depths of 50 cm in the area outside the canopy for C. korshinskii and H. rhamnoides suggested that more rain water can be conserved into the deep soil layers through shrub stemflow. Soil moisture was enhanced in the area outside the shrub canopy, only when rainfall depth is > 4.7 and 5.1 mm, which is an effective rainfall for the area for C. korshinskii and H. rhamnoides. While for the area around stem of C. korshinskii and H. rhamnoides, the corresponding threshold values are 3.2 and 4.3 mm. These results confirmed that stemflow has a positive effect on soil moisture balance of the root zone and the enhancement in soil moisture of deeper soil layers.

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Analyzing Trends in Water Table Elevations at the Marcell Experimental Forest, Minnesota, U.S.A.

American Journal of Undergraduate Research ◽

10.33697/ajur.2020.032 ◽

2021 ◽

Vol 17 (4) ◽

pp. 19-32

Author(s):

Anna Stockstad ◽

Ella Gray ◽

Stephen Sebestyen ◽

Nina Lany ◽

Randall Kolka ◽

...

Keyword(s):

Water Table ◽

Linear Trend ◽

Forest Products ◽

Water Levels ◽

Monthly Precipitation ◽

Significant Linear Trend ◽

Water Table Fluctuations ◽

Water Tables ◽

Over Time

Water table fluctuations in peatlands are closely coupled with the local climate setting and drive critical ecosystem processes such as nutrient cycling. In Minnesota, USA, peatlands cover ten percent of the surface area, approximately 2.5 million hectares, some of which are actively managed for forest products. To explore the relationship between peatland water tables and precipitation, long-term data (1961 to 2019) were used from the Marcell Experimental Forest in northern Minnesota. Starting in 1961, water table data from seven peatlands, including two types of peatlands (bogs and fens), were measured. We used the Theil-Sen estimator to test for monotonic trends in mean monthly water table elevations for individual peatlands and monthly precipitation. Water levels in bogs were both more variable and had mean water table elevations that were closer to the surface. Individual trends of water table elevations differed among peatlands. Water table elevations increased over time in three of the bogs studied and decreased over time in two of the bogs studied. Trends within fens were notably nonlinear across time. No significant linear trend was found for mean monthly precipitation between 1961 and 2019. These results highlight differences in peatlands types, local physiography, and the importance of understanding how changes in long-term dynamics coupled with changing current conditions will influence the effects of water table fluctuations on ecosystem services. The variability of water table elevations in bogs poses potential difficulties in modeling these ecosystems or creating adaptive management plans. KEYWORDS: Peatlands; Hydrology; Water tables; Bogs; Fens; Monitoring; Minnesota; Climate Change

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Effects of Temporary Water-tables on Marsh Grapefruit Trees in Sudan

Experimental Agriculture ◽

10.1017/s0014479700006013 ◽

1974 ◽

Vol 10 (4) ◽

pp. 247-250

Author(s):

S. B. Abbadi ◽

F. A. Minessy ◽

A. T. Abdelhafeez

Keyword(s):

Water Table ◽

Root Zone ◽

Soil Surface ◽

Leaf Size ◽

Size Number ◽

Water Tables ◽

Temporary Water ◽

Moisture Characteristic ◽

Number Of Leaves ◽

Different Parts

SUMMARYTwo weeks after irrigation there was a temporary water-table between 30 and 127 cm. below the soil surface in four different parts of a grapefruit orchard. As the temporary water-table rose closer to the soil surface the percentage of soil water in the root zone increased and tree size, number of leaves per branch, and leaf size all decreased. Shallow water-tables also induced more die-back and reduced yields significantly. Analyses of soils at various sites indicated that there was no problem of salinity or alkalinity, but physical soil analyses showed that the percentage of clay increased with increased shallowness of the water-table, in line with the soil moisture characteristic curves.

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Characteristics and controls of variability in soil moisture and groundwater in a headwater catchment

Hydrology and Earth System Sciences ◽

10.5194/hess-19-1767-2015 ◽

2015 ◽

Vol 19 (4) ◽

pp. 1767-1786 ◽

Cited By ~ 23

Author(s):

H. K. McMillan ◽

M. S. Srinivasan

Keyword(s):

Soil Moisture ◽

Spatial Variability ◽

Water Table ◽

Temporal Variability ◽

Potential Evapotranspiration ◽

Spatial And Temporal Variability ◽

Multiple Time ◽

Runoff Generation ◽

Dominant Type ◽

Water Tables

Abstract. Hydrological processes, including runoff generation, depend on the distribution of water in a catchment, which varies in space and time. This paper presents experimental results from a headwater research catchment in New Zealand, where we made distributed measurements of streamflow, soil moisture and groundwater levels, sampling across a range of aspects, hillslope positions, distances from stream and depths. Our aim was to assess the controls, types and implications of spatial and temporal variability in soil moisture and groundwater tables. We found that temporal variability in soil moisture and water table is strongly controlled by the seasonal cycle in potential evapotranspiration, for both the mean and extremes of their distributions. Groundwater is a larger water storage component than soil moisture, and this general difference increases even more with increasing catchment wetness. The spatial standard deviation of both soil moisture and groundwater is larger in winter than in summer. It peaks during rainfall events due to partial saturation of the catchment, and also rises in spring as different locations dry out at different rates. The most important controls on spatial variability in storage are aspect and distance from the stream. South-facing and near-stream locations have higher water tables and showed soil moisture responses for more events. Typical hydrological models do not explicitly account for aspect, but our results suggest that it is an important factor in hillslope runoff generation. Co-measurement of soil moisture and water table level allowed us to identify relationships between the two. Locations where water tables peaked closer to the surface had consistently wetter soils and higher water tables. These wetter sites were the same across seasons. However, patterns of strong soil moisture responses to summer storms did not correspond to the wetter sites. Total catchment spatial variability is composed of multiple variability sources, and the dominant type is sensitive to those stores that are close to a threshold such as field capacity or saturation. Therefore, we classified spatial variability as "summer mode" or "winter mode". In "summer mode", variability is controlled by shallow processes, e.g. interaction of water with soils and vegetation. In "winter mode", variability is controlled by deeper processes, e.g. groundwater movement and bypass flow. Double streamflow peaks observed during some events show the direct impact of groundwater variability on runoff generation. Our results suggest that emergent catchment behaviour depends on the combination of these multiple, time varying components of storage variability.

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Satellite Determination of Peatland Water Table Temporal Dynamics by Localizing Representative Pixels of A SWIR-Based Moisture Index

Remote Sensing ◽

10.3390/rs12182936 ◽

2020 ◽

Vol 12 (18) ◽

pp. 2936

Author(s):

Iuliia Burdun ◽

Michel Bechtold ◽

Valentina Sagris ◽

Annalea Lohila ◽

Elyn Humphreys ◽

...

Keyword(s):

Time Series ◽

Soil Moisture ◽

Water Table ◽

Land Surface ◽

Temporal Dynamics ◽

Root Zone ◽

Pearson Correlation ◽

Remotely Sensed ◽

Rooting Depth ◽

Surface Model

The OPtical TRApezoid Model (OPTRAM) is a physically-based approach for remote soil moisture estimation. OPTRAM is based on the response of short-wave infrared (SWIR) reflectance to vegetation water status, which in turn responds to changes of root-zone soil moisture. In peatlands, the latter is tightly coupled to water table depth (WTD). Therefore, in theory, the OPTRAM index might be a useful tool to monitor WTD dynamics in peatlands, although the sensitivity of OPTRAM index to WTD changes will likely depend on vegetation cover and related rooting depth. In this study, we aim at identifying those locations (further called ‘best pixels’) where the OPTRAM index is most representative of overall peatland WTD dynamics. In peatlands, the high saturated hydraulic conductivity of the upper layer largely synchronizes the temporal WTD fluctuations over several kilometers, i.e., even though the mean and amplitude of the WTD dynamics may vary in space. Therefore, it can be assumed that the WTD time series, either measured at a single location or simulated for a grid cell with the PEATland-specific adaptation of the NASA Catchment Land Surface Model (PEATCLSM), are representative of the overall peatland WTD dynamics. We took advantage of this concept to identify the ‘best pixel’ of all spatially distributed OPTRAM pixels within a peatland, as that pixel with the highest time series Pearson correlation (R) with WTD data accounting for temporal autocorrelation. The OPTRAM index was calculated based on various remotely sensed images, namely, Landsat, MODIS, and aggregated Landsat images at MODIS resolution for five northern peatlands with long-term WTD records, including both bogs and fens. The ‘best pixels’ were dominantly covered with mosses and graminoids with little or no shrub or trees. However, the performance of OPTRAM highly depended on the spatial resolution of the remotely sensed data. The Landsat-based OPTRAM index yielded the highest R values (mean of 0.7 across the ‘best pixels’ in five peatlands). Our study further indicates that, in the absence of historical in situ data, PEATCLSM can be used as an alternative to localize ‘best pixels’. This finding enables the future applicability of OPTRAM to monitor WTD changes in peatlands on a global scale.

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Grafted Watermelon Root Length Density and Distribution under Different Soil Moisture Treatments

HortScience ◽

10.21273/hortsci.48.8.1021 ◽

2013 ◽

Vol 48 (8) ◽

pp. 1021-1026 ◽

Cited By ~ 6

Author(s):

Gilbert Miller ◽

Ahmad Khalilian ◽

Jeffrey W. Adelberg ◽

Hamid J. Farahani ◽

Richard L. Hassell ◽

...

Keyword(s):

Soil Moisture ◽

Root Length ◽

Root Zone ◽

Root Length Density ◽

Soil Depth ◽

Citrullus Lanatus ◽

Irrigation Management ◽

Irrigation Treatment ◽

System Size ◽

Deep Soil

Delineating the depth and extent of the watermelon [Citrullus lanatus (Thumb.) Matsum. & Nak.] root zone assists with proper irrigation management and minimizes nutrient leaching. The objective of this 3-year field study was to measure root distribution and root length density of watermelon (cv. Wrigley) grafted on two different rootstocks (Lagenaria siceraria cv. ‘FR Strong’ and Cucurbita moschata × Cucurbita maxima cv. Chilsung Shintoza) and grown under three soil moisture treatments. Irrigation treatments tested were: no irrigation (NI), briefly irrigated for fertigation and early-season plant establishment; minimally irrigated (MI), irrigated when soil moisture in top 0.30 m of soil fell below 50% available water capacity (AWC); well irrigated (WI), irrigated when soil moisture in top 0.30 m of soil fell below 15% (AWC). Root length density (RLD) was measured from 75-cm-deep soil cores at two locations three times per growing season and a third location at the end of the season. Cores 1 and 2 sample locations were 15 cm to the side of each plant: Core 1 on the same side as the drip tape and Core 2 on the opposite side. At the end of the season, Core 3 was taken 15 cm outside of the bed in bare ground. RLD was significantly greater in the 0- to 30-cm soil depth and dropped dramatically below 30 cm; it was not significantly affected by irrigation treatment or rootstock. Core 1, next to the drip tape, had greater RLD than Core 2, 30 cm from drip tape, but only at the later sampling dates. Roots were found in Core 3 at all depths, but the RLD was significantly less than that measured in Cores 1 and 2. These findings suggest that the effective root zone depth for watermelon is 0 to 30 cm and that the particular scion/rootstock combinations tested in this study do not differ in root system size or location.

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