scholarly journals Multi-channel ground-penetrating radar to explore spatial variations in thaw depth and moisture content in the active layer of a permafrost site

2010 ◽  
Vol 4 (3) ◽  
pp. 269-283 ◽  
Author(s):  
U. Wollschläger ◽  
H. Gerhards ◽  
Q. Yu ◽  
K. Roth
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Active Layer ◽  
Ground Penetrating Radar ◽  
Soil Moisture Content ◽  
Late Summer ◽  
Bare Soil ◽  
Thaw Depth ◽  
Ground Penetrating ◽  
Gravel Road

Abstract. Multi-channel ground-penetrating radar (GPR) was applied at a permafrost site on the Tibetan Plateau to investigate the influence of surface properties and soil texture on the late-summer thaw depth and average soil moisture content of the active layer. Measurements were conducted on an approximately 85 × 60 m2 sized area with surface and soil textural properties that ranged from medium to coarse textured bare soil to finer textured, sparsely vegetated areas covered with fine, wind blown sand, and it included the bed of a gravel road. The survey allowed a clear differentiation of the various units. It showed (i) a shallow thaw depth and low average soil moisture content below the sand-covered, vegetated area, (ii) an intermediate thaw depth and high average soil moisture content along the gravel road, and (iii) an intermediate to deep thaw depth and low to intermediate average soil moisture content in the bare soil terrain. From our measurements, we found hypotheses for the permafrost processes at this site leading to the observed late-summer thaw depth and soil moisture conditions. The study clearly indicates the complicated interactions between surface and subsurface state variables and processes in this environment. Multi-channel GPR is an operational technology to efficiently study such a system at scales varying from a few meters to a few kilometers.

scholarly journals Multi-channel ground-penetrating radar to explore spatial variations in thaw depth and moisture content in the active layer of a permafrost site

2009 ◽  
Vol 3 (3) ◽  
pp. 919-946 ◽  
Author(s):  
U. Wollschläger ◽  
H. Gerhards ◽  
Q. Yu ◽  
K. Roth
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Active Layer ◽  
Ground Penetrating Radar ◽  
Soil Moisture Content ◽  
Late Summer ◽  
Bare Soil ◽  
Thaw Depth ◽  
Ground Penetrating ◽  
Gravel Road

Abstract. Multi-channel ground-penetrating radar was applied at a permafrost site on the Tibetan Plateau to investigate the influence of surface properties and soil texture on the late-summer thaw depth and average soil moisture content of the active layer. Measurements were conducted on an approximately 85×60 m2 sized area with surface and soil textural properties that ranged from medium to coarse textured bare soil to finer textured, vegetated areas covered with fine, wind blown sand, and it included the bed of a gravel road. The survey allowed a clear differentiation of the various units. It showed (i) a shallow thaw depth and low average soil moisture content below the sand-covered, vegetated area, (ii) an intermediate thaw depth and high average soil moisture content along the gravel road, and (iii) an intermediate to deep thaw depth and low to intermediate average soil moisture content in the bare soil terrain. From our measurements, we found plausible hypotheses for the permafrost processes at this site leading to the observed late-summer thaw depth and soil moisture conditions. The study clearly indicates the complicated interactions between surface and subsurface state variables and processes in this environment. In addition, the survey demonstrates the potential of multi-channel ground-penetrating radar to efficiently map thaw depth and soil moisture content of the active layer with high spatial resolution at scales from a few meters to a few kilometers.

scholarly journals Laboratory Measurements of Subsurface Spatial Moisture Content by Ground-Penetrating Radar (GPR) Diffraction and Reflection Imaging of Agricultural Soils

2018 ◽  
Vol 10 (10) ◽  
pp. 1667 ◽  
Author(s):  
Omer Shamir ◽  
Naftaly Goldshleger ◽  
Uri Basson ◽  
Moshe Reshef
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Soil Type ◽  
Soil Moisture Content ◽  
Root Zone ◽  
Effective Dielectric Constant ◽  
Agricultural Practice ◽  
Ground Penetrating

Soil moisture content (SMC) down to the root zone is a major factor for the efficient cultivation of agricultural crops, especially in arid and semi-arid regions. Precise SMC can maximize crop yields (both quality and quantity), prevent crop damage, and decrease irrigation expenses and water waste, among other benefits. This study focuses on the subsurface spatial electromagnetic mapping of physical properties, mainly moisture content, using a ground-penetrating radar (GPR). In the laboratory, GPR measurements were carried out using an 800 MHz central-frequency antenna and conducted in soil boxes with loess soil type (calcic haploxeralf) from the northern Negev, hamra soil type (typic rhodoxeralf) from the Sharon coastal plain, and grumusol soil type (typic chromoxerets) from the Jezreel valley, Israel. These measurements enabled highly accurate, close-to-real-time evaluations of physical soil qualities (i.e., wave velocity and dielectric constant) connected to SMC. A mixture model based mainly on soil texture, porosity, and effective dielectric constant (permittivity) was developed to measure the subsurface spatial volumetric soil moisture content (VSMC) for a wide range of moisture contents. The analysis of the travel times for GPR reflection and diffraction waves enabled calculating electromagnetic velocities, effective dielectric constants, and spatial SMC under laboratory conditions, where the required penetration depth is low (root zone). The average VSMC was determined with an average accuracy of ±1.5% and was correlated to a standard oven-drying method, making this spatial method useful for agricultural practice and for the design of irrigation plans for different interfaces.

Ground-penetrating radar-derived measurements of active-layer thickness on the landscape scale with sparse calibration at Toolik and Happy Valley, Alaska

Geophysics ◽  
2016 ◽  
Vol 81 (2) ◽  
pp. H9-H19 ◽  
Author(s):  
Albert Chen ◽  
Andrew D. Parsekian ◽  
Kevin Schaefer ◽  
Elchin Jafarov ◽  
Santosh Panda ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Ground Penetrating Radar ◽  
Empirical Relationship ◽  
Monitoring Network ◽  
Active Layer Thickness ◽  
Antenna Coupling ◽  
Thaw Depth ◽  
Ground Penetrating ◽  
Happy Valley

Active-layer thickness (ALT) is an important parameter for studying surface energy balance, ecosystems, and hydrologic processes in cold regions. We measured ALT along 10 routes with lengths ranging from 0.7 to 6.9 km located on the Alaska North Slope near Toolik Lake and the Happy Valley airstrip (between 68.475° and 69.150°N, and [Formula: see text] and [Formula: see text]). Using a ground-penetrating radar (GPR) system in a common-offset configuration, we measured the two-way traveltimes from the surface to the bottom of the active layer at the end of summer, when the thaw depth was greatest. We used 500 and 800 MHz antennas; the 500 MHz antenna provided suitable vertical resolution, while producing more unambiguous active-layer reflections in the presence of nonideal antenna coupling and active layer inhomogeneity. We derived ALT measurements and their uncertainties from GPR two-way traveltimes, with mechanical probing for velocity calibration. Using an empirical relationship between the wave velocity and soil volumetric water content (VWC), we found that the velocities were consistent with soil VWCs ranging from 0.46 to 0.63. In 31% of traces, the permafrost table horizon was identifiable, resulting in ALT measurements with uncertainties of generally less than 25%. The average ALT was 48.1 cm, with a standard deviation of 16.1 cm. We found distinct patterns of ALT spatial variability at different sites and different length scales. At some sites, the ALT at one point was effectively uncorrelated with ALT at other points separated by lag distances as small as tens of meters; for other sites, there was correlation at lag distances up to approximately 400 m. The ALT statistics were similar to nearby long-term in situ ALT measurements from the Circumpolar Active Layer Monitoring Network, through which yearly ALT measurements have been made since 1990.

scholarly journals Influence of soil texture on the estimation of bare soil moisture content using MODIS images

2018 ◽  
Vol 51 (1) ◽  
pp. 911-920
Author(s):  
Nabi Olah Gholami Bidkhani ◽  
Mohammad Reza Mobasheri
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Texture ◽  
Soil Moisture Content ◽  
Bare Soil

scholarly journals Estimations of moisture content in the active layer in an Arctic ecosystem by using ground-penetrating radar profiling

2012 ◽  
Vol 79 ◽  
pp. 100-106 ◽  
Author(s):  
Guisella Gacitúa ◽  
Mikkel Peter Tamstorf ◽  
Søren Munch Kristiansen ◽  
José Andrés Uribe
Keyword(s):  
Moisture Content ◽  
Active Layer ◽  
Ground Penetrating Radar ◽  
Arctic Ecosystem ◽  
Ground Penetrating

scholarly journals MAPPING SPATIAL MOISTURE CONTENT OF UNSATURATED AGRICULTURAL SOILS WITH GROUND-PENETRATING RADAR

2016 ◽  
Vol XLI-B8 ◽  
pp. 1279-1285 ◽  
Author(s):  
O. Shamir ◽  
N. Goldshleger ◽  
U. Basson ◽  
M. Reshef
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Rural Areas ◽  
Soil Type ◽  
Root Zone ◽  
Agricultural Soils ◽  
Model Development ◽  
Physical Computing ◽  
Ground Penetrating

Soil subsurface moisture content, especially in the root zone, is important for evaluation the influence of soil moisture to agricultural crops. Conservative monitoring by point-measurement methods is time-consuming and expensive. In this paper we represent an active remote-sensing tool for subsurface spatial imaging and analysis of electromagnetic physical properties, mostly water content, by ground-penetrating radar (GPR) reflection. Combined with laboratory methods, this technique enables real-time and highly accurate evaluations of soils' physical qualities in the field. To calculate subsurface moisture content, a model based on the soil texture, porosity, saturation, organic matter and effective electrical conductivity is required. We developed an innovative method that make it possible measures spatial subsurface moisture content up to a depth of 1.5 m in agricultural soils and applied it to two different unsaturated soil types from agricultural fields in Israel: loess soil type (Calcic haploxeralf), common in rural areas of southern Israel with about 30% clay, 30% silt and 40% sand, and hamra soil type (Typic rhodoxeralf), common in rural areas of central Israel with about 10% clay, 5% silt and 85% sand. Combined field and laboratory measurements and model development gave efficient determinations of spatial moisture content in these fields. The environmentally friendly GPR system enabled non-destructive testing. The developed method for measuring moisture content in the laboratory enabled highly accurate interpretation and physical computing. Spatial soil moisture content to 1.5 m depth was determined with 1–5% accuracy, making our method useful for the design of irrigation plans for different interfaces.

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