scholarly journals Active Layer Thickness Retrieval Over the Qinghai-Tibet Plateau Using Sentinel-1 Multitemporal InSAR Monitored Permafrost Subsidence and Temporal-Spatial Multilayer Soil Moisture Data

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 84336-84351 ◽  
Author(s):  
Xuefei Zhang ◽  
Hong Zhang ◽  
Chao Wang ◽  
Yixian Tang ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Layer Thickness ◽  
Active Layer ◽  
Tibet Plateau ◽  
Active Layer Thickness ◽  
Soil Moisture Data ◽  
Qinghai Tibet Plateau

scholarly journals ACTIVE LAYER THICKNESS RETRIEVAL OVER THE QINGHAI-TIBET PLATEAU FROM 2000 TO 2020 BASED ON INSAR-MEASURED SUBSIDENCE AND MULTI-LAYER SOIL MOISTURE

2021 ◽  
Vol XLIII-B3-2021 ◽  
pp. 437-442
Author(s):  
T. Chang ◽  
J. Han ◽  
Z. Li ◽  
Y. Wen ◽  
T. Hao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Layer Thickness ◽  
Active Layer ◽  
Surface Deformation ◽  
Tibet Plateau ◽  
Active Layer Thickness ◽  
Permafrost Region ◽  
Radar Images ◽  
Soil Moisture Data ◽  
Qinghai Tibet Plateau

Abstract. Active layer thickness (ALT) is an important index to reflect the stability of permafrost. The retrieval of ALT based on Interferometric Synthetic Aperture Radar (InSAR) technology has been investigated recently in permafrost research. However, most of such studies are carried out in a limited extend and relatively short temporal coverage. The combination of temporal-spatial multi-layer soil moisture data and multi-temporal InSAR is a promising approach for the large-scale characterization of ALT. In this study, we employed Small Baseline Subset Interferometry (SBAS-InSAR) technology to obtain the seasonal surface deformation from radar images of Envisat and Sentinel-1 in a permafrost region of Qinghai-Tibet Plateau (QTP). We attempt to verify and calibrate the temporal-spatial multi-layer soil moisture product in combination with the in-situ data. Based on the land subsidence data and the temporal-spatial multi-layer soil moisture data, we further improve method to retrieve the ALT information. This paper describes the progress so far and point out the future work.

Active layer thickness calculation over the Qinghai–Tibet Plateau

2009 ◽  
Vol 57 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Qiangqiang Pang ◽  
Guodong Cheng ◽  
Shuxun Li ◽  
Wengang Zhang
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Tibet Plateau ◽  
Active Layer Thickness ◽  
Qinghai Tibet Plateau

scholarly journals Soil moisture redistribution and its effect on inter-annual active layer temperature and thickness variations in a dry loess terrace in Adventdalen, Svalbard

2016 ◽  
Author(s):  
C. Schuh ◽  
A. Frampton ◽  
H. H. Christiansen
Keyword(s):  
Soil Moisture ◽  
Layer Thickness ◽  
Active Layer ◽  
Field Data ◽  
Large Field ◽  
Thickness Variation ◽  
Unfrozen Water ◽  
Active Layer Thickness ◽  
Retention Characteristics ◽  
Moisture Redistribution

Abstract. High resolution field data for the period 2000–2014 consisting of active layer and permafrost temperature, active layer soil moisture, and thaw depth progression from the UNISCALM research site in Adventdalen, Svalbard, is combined with a physically-based coupled cryotic and hydrogeological model to investigate active layer dynamics. The site is a loess-covered river terrace characterized by dry conditions with little to no summer infiltration and an unsaturated active layer. A range of soil moisture characteristic curves consistent with loess sediments are considered and their effects on ice and moisture redistribution, heat flux, energy storage through latent heat transfer, and active layer thickness is investigated and quantified based on hydro-climatic site conditions. Results show that soil moisture retention characteristics exhibit notable control of ice distribution and circulation within the active layer by cryosuction subject to seasonal variability and site-specific surface temperature variations. The retention characteristics also impact unfrozen water and ice content in the permafrost. Although these effects lead to differences in thaw progression rates, the resulting inter-annual variability in active layer thickness is not large. Field data analysis reveals that variations in summer degree days do not notably affect the active layer thaw depths; instead, a cumulative winter degree day index is found to more significantly control inter-annual active layer thickness variation at this site. A tendency of increasing winter temperatures is found to cause a general warming of the subsurface down to 10 m depth (0.05 to 0.26 ˚C/yr, observed and modelled) including an increasing active layer thickness (0.8 cm/yr, observed and 0.3 to 0.8 cm/yr, modelled) during the 14-year study period.

Permafrost Dynamics Observatory: Retrieval of Active Layer Thickness and Soil Moisture from Airborne Insar and Polsar Data

2021 ◽  
Author(s):  
Richard H. Chen ◽  
Roger J. Michaelides ◽  
Yuhuan Zhao ◽  
Lingcao Huang ◽  
Elizabeth Wig ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Layer Thickness ◽  
Active Layer ◽  
Active Layer Thickness

scholarly journals Recent Changes to the Hydrological Cycle of an Arctic basin at the Tundra-Taiga Transition

2018 ◽  
Author(s):  
Sebastian A. Krogh ◽  
John W. Pomeroy
Keyword(s):  
Soil Moisture ◽  
Layer Thickness ◽  
Active Layer ◽  
Snow Water Equivalent ◽  
Hydrological Cycle ◽  
Hydrological Processes ◽  
Active Layer Thickness ◽  
Blowing Snow ◽  
Hydrological Changes ◽  
The Impact

Abstract. The impact of observed changes in climate and vegetation on the hydrology of Arctic basins is often considered to be most sensitive at the tundra-taiga transition where the region is warmest and sub-arctic vegetation is nearest. This study uses weather and land cover observations and a cold regions hydrological model to investigate historical changes in modelled hydrological processes driving the streamflow response of a small Arctic permafrost-underlain basin at the tundra-taiga transition. The physical processes found in this environment and explicit changes in vegetation type and density were simulated and validated against observations of streamflow discharge, snow water equivalent and active layer thickness. Mean air temperature and all-wave irradiance have increased by 3.7 °C and 8.4 W m−2, respectively, while precipitation has decreased from 369 to 321 mm since 1960. Two modelling scenarios were created to separate the effects of changing climate and vegetation on hydrological processes. Results show that over 1960–2016 most hydrological changes were driven by climate changes, such as decreasing snowfall by 7.8 mm decade−1, deepening active layer thickness by 1.8–4.2 cm decade−1, earlier snowcover depletion and ground thaw initiation dates from 1.5 to 3 and by 1 to 3 days decade−1, respectively, and diminishing annual sublimation and soil moisture by 1.3 and 5.9 mm decade−1, respectively. Evapotranspiration decreased by 2.5 mm decade−1, due to decreasing irradiance and soil moisture. Shrub expansion and densification decreases blowing snow redistribution by 20 to 40 mm and sublimation by 1 to 10 mm. Streamflow dropped by 40 mm as a response to the 48 mm decrease in precipitation, suggesting a small degree of hydrological resiliency. These results represent the first detailed estimate of hydrological changes occurring in small Arctic basins, and can be used as a reference to inform other studies of Arctic climate change impacts.

scholarly journals Response of freeze-thaw processes to experimental warming in the permafrost regions of the central Qinghai-Tibet Plateau

2016 ◽  
Author(s):  
Shengyun Chen ◽  
Wenjie Liu ◽  
Qian Zhao ◽  
Lin Zhao ◽  
Qingbai Wu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Moisture Content ◽  
Tibet Plateau ◽  
Active Layer Thickness ◽  
Experimental Warming ◽  
Freeze Thaw ◽  
Alpine Steppe ◽  
Steppe Ecosystems ◽  
Qinghai Tibet Plateau ◽  
Permafrost Regions

Abstract. Assessing quantitatively effect of climate warming on freeze/thaw index (FI/TI), soil freeze-thaw processes and active layer thickness (ALT) is still lacking in the permafrost regions of the Qinghai-Tibet Plateau (QTP) until now. Experimental warming was manipulated using open top chambers (OTCs) in alpine swamp meadow and alpine steppe ecosystems in the permafrost regions of the central QTP during 2009–2011. Under OTCs treatment, air temperature (Ta) significantly increased in the daytime and decreased in the nighttime, diurnal and annual Ta range significantly enhanced, and mean annual Ta increased by 1.4 °C. Owing to the experimental warming, mean annual soil temperature at the depths from 5 cm to 40 cm was increased by 0.2 ~ 0.7 °C in alpine swamp meadow and 0.3 ~ 1.5 °C in alpine steppe. Mean annual soil moisture content at 10 cm depth decreased by 1.1 % and 0.8 %, and mean annual soil salinity at 10 cm depth significantly increased by 0.3 g L-1 and 0.1 g L-1 in alpine swamp meadow and alpine steppe, respectively. Further, FI was significantly decreased by 410.7 °C d while TI was significantly increased by 460.7 °C d. Likewise, the onset dates of shallow soil thawing at 5–40 cm depths were advanced by 9 days and 8 days while the onset dates of freezing were delayed by 10 days and 4 days in alpine swamp meadow and alpine steppe, respectively. Moreover, soil frozen days were significantly decreased by 28 days and 16 days, but thawed days were increased by 18 days and 6 days, and frozen-thawed days were significantly increased by 10 days and 10 days in alpine swamp meadow and alpine steppe, respectively. Furthermore, ALT would be significantly increased by ~ 6.9 cm and ~ 19.6 cm in alpine swamp meadow and alpine steppe ecosystems, respectively.

scholarly journals Soil Moisture Calibration Equations for Active Layer GPR Detection—a Case Study Specially for the Qinghai–Tibet Plateau Permafrost Regions

2020 ◽  
Vol 12 (4) ◽  
pp. 605
Author(s):  
Erji Du ◽  
Lin Zhao ◽  
Defu Zou ◽  
Ren Li ◽  
Zhiwei Wang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Active Layer ◽  
Complex Refractive Index ◽  
Tibet Plateau ◽  
Data Set ◽  
Calibration Equation ◽  
Qinghai Tibet Plateau ◽  
Moisture Estimation ◽  
Permafrost Regions

Ground-penetrating radar (GPR) is a convenient geophysical technique for active-layer soil moisture detection in permafrost regions, which is theoretically based on the petrophysical relationship between soil moisture (θ) and the soil dielectric constant (ε). The θ–ε relationship varies with soil type and thus must be calibrated for a specific region or soil type. At present, there is lack of such a relationship for active-layer soil moisture estimation for the Qinghai–Tibet plateau permafrost regions. In this paper, we utilize the Complex Refractive Index Model to establish such a calibration equation that is suitable for active-layer soil moisture estimation with GPR velocity. Based on the relationship between liquid water, temperature, and salinity, the soil water dielectric constant was determined, which varied from 84 to 88, with an average value of 86 within the active layer for our research regions. Based on the calculated soil-water dielectric constant variation range, and the exponent value range within the Complex Refractive Index Model, the exponent value was determined as 0.26 with our field-investigated active-layer soil moisture and dielectric data set. By neglecting the influence of the soil matrix dielectric constant and soil porosity variations on soil moisture estimation at the regional scale, a simple active-layer soil moisture calibration curve, named CRIM, which is suitable for the Qinghai–Tibet plateau permafrost regions, was established. The main shortage of the CRIM calibration equation is that its calculated soil-moisture error will gradually increase with a decreasing GPR velocity and an increasing GPR velocity interpretation error. To avoid this shortage, a direct linear fitting calibration equation, named as υ-fitting, was acquired based on the statistical relationship between the active-layer soil moisture and GPR velocity with our field-investigated data set. When the GPR velocity interpretation error is within ±0.004 m/ns, the maximum moisture error calculated by CRIM is within 0.08 m3/m3. While when the GPR velocity interpretation error is larger than ±0.004 m/ns, a piecewise formula calculation method, combined with the υ-fitting equation when the GPR velocity is lower than 0.07 m/ns and the CRIM equation when the GPR velocity is larger than 0.07 m/ns, was recommended for the active-layer moisture estimation with GPR detection in the Qinghai–Tibet plateau permafrost regions.

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