Permafrost Hydrology of the Qinghai-Tibet Plateau: A Review of Processes and Modeling

Frontiers in Earth Science, Journal Year: 2021, Volume and Issue: 8

Published: Jan. 12, 2021

Permafrost extends 40% of the Qinghai-Tibet Plateau (QTP), a region which contains headwaters numerous major rivers in Asia. As an aquiclude, permafrost substantially controls surface runoff and its hydraulic connection with groundwater. The freeze–thaw cycle active layer significantly impacts soil water movement direction, velocity, storage capacity, conductivity. Under accelerating warming on QTP, degradation is drastically altering regional even continental hydrological regimes, attracting attention hydrologists, climatologists, ecologists, engineers, decision-makers. A systematic review processes modeling QTP still lacking, however, leaving number knowledge gaps. In this review, we summarize current understanding applications some models varying complexity at different scales QTP. We then discuss challenges future opportunities, including observations data, processes, model realism. goal to provide clear picture where are now describe opportunities. concluded that more efforts needed conduct long-term field measurements, employ advanced observation technologies, develop flexible modular deepen our improve ability predict responses hydrology climate changes.

Language: Английский

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An Integrative Information Aqueduct to Close the Gaps between Satellite Observation of Water Cycle and Local Sustainable Management of Water Resources

Water, Journal Year: 2020, Volume and Issue: 12(5), P. 1495 - 1495

Published: May 23, 2020

The past decades have seen rapid advancements in space-based monitoring of essential water cycle variables, providing products related to precipitation, evapotranspiration, and soil moisture, often at tens kilometer scales. Whilst these data effectively characterize variability regional global scales, they are less suitable for sustainable management local resources, which needs detailed information represent the spatial heterogeneity vegetation. following questions critical exploit from remotely sensed situ Earth observations (EOs): How downscale scale using multiple sources scales EO data? explore apply downscaled level a better understanding soil-water-vegetation-energy processes? can such fine-scale be used improve resources? An integrative flow (i.e., iAqueduct theoretical framework) is developed close gaps between satellite necessary resources. integrated framework aims address abovementioned scientific by combining medium-resolution (10 m–1 km) Copernicus with high-resolution (cm) unmanned aerial system (UAS) data, observations, analytical- physical-based models, as well big-data analytics machine learning algorithms. This paper provides general overview introduces some preliminary results.

Language: Английский

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Water Migration and Segregated Ice Formation in Frozen Ground: Current Advances and Future Perspectives

Frontiers in Earth Science, Journal Year: 2022, Volume and Issue: 10

Published: Feb. 10, 2022

A characteristic of frozen ground is a tendency to form banded sequences particle-free ice lenses separated by layers ice-infiltrated soil, which produce frost heave. In permafrost, the deformation surface caused segregated harms engineering facilities and has considerable influences on regional hydrology, ecology, climate changes. For predicting impacts permafrost degradation under global warming transformation environmental, establishing appropriate mathematical models describe water migration behavior in soil necessary. This requires an essential understanding formation ground. article reviewed mechanisms soils their model construction introduced effects environment included landforms, hydrological patterns, ecosystems. Currently, potential been widely accepted characterize energy state liquid water, further study direction flux moisture migration. Models aimed dynamics have successfully predicted macroscopic processes ice, such as rigid segregation model, used developed. However, some difficulties theoretical basis microscope physics still need study. Besides, how lens landscape another interesting challenge that helps understand interaction between environment. final this review, concerns overlooked current research summarized should be central focus future

Language: Английский

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Investigation, Monitoring, and Simulation of Permafrost on the Qinghai‐Tibet Plateau: A Review

Permafrost and Periglacial Processes, Journal Year: 2024, Volume and Issue: 35(3), P. 412 - 422

Published: March 25, 2024

ABSTRACT The Qinghai‐Tibet Plateau (QTP) is the largest permafrost region in world at low and middle latitudes high elevation. Permafrost being degraded on QTP due to global warming, which has a significant effect regional climate, hydrological, ecological processes. This paper provides summary of recent progress methods used research, distribution, basic data relevant research QTP. area was 1.32 × 10 6 km 2 over QTP, accounts for approximately 46% Moreover, simulation studies hydrothermal process change were reviewed evaluated degradation hydrological results revealed that effects runoff closely related soil temperature, carbon cycle requires further study. Finally, current challenges processes discussed, emphasizing under climate slow non‐linear process. review will aid future examining mechanism underlying interaction between change, environmental protection regions

Language: Английский

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Understanding the mass, momentum, and energy transfer in the frozen soil with three levels of model complexities

Hydrology and earth system sciences, Journal Year: 2020, Volume and Issue: 24(10), P. 4813 - 4830

Published: Oct. 12, 2020

Abstract. Frozen ground covers a vast area of the Earth's surface and it has important ecohydrological implications for cold regions under changing climate. However, is challenging to characterize simultaneous transfer mass energy in frozen soils. Within modeling framework Simultaneous Transfer Mass, Momentum, Energy Unsaturated Soil (STEMMUS), complexity soil heat model varies from basic coupled (termed BCM) advanced (ACM), and, furthermore, explicit consideration airflow (ACM–AIR). The impact different complexities on understanding mass, momentum, was investigated. performance simulating water latent flux evaluated over typical Tibetan plateau meadow site. Results indicate that ACM considerably improved simulation moisture, temperature, flux. analysis budget reveals improvement temperature simulations by attributed its physical vapor flow thermal effect flow, with former mainly functioning above evaporative front latter dominating below front. contribution airflow-induced transport (driven air pressure gradient) total fluxes negligible. Nevertheless, given airflow, effects were enhanced during freezing–thawing transition period.

Language: Английский

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Development of the Hydrus-1D freezing module and its application in simulating the coupled movement of water, vapor, and heat

Journal of Hydrology, Journal Year: 2021, Volume and Issue: 598, P. 126250 - 126250

Published: March 26, 2021

Language: Английский

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Disentangling the Impact of Event‐ and Annual‐Scale Precipitation Extremes on Critical‐Zone Hydrology in Semiarid Loess Vegetated by Apple Trees

Water Resources Research, Journal Year: 2023, Volume and Issue: 59(3)

Published: Feb. 25, 2023

Abstract The extent and mechanisms by which precipitation extremes affect hydrological processes in the critical zone (CZ) of loess possessing a thick unsaturated remains poorly understood. To this end, we here employed coupled liquid‒vapor‒heat‒airflow STEMMUS (simultaneous transfer energy, mass, momentum soil) model to investigate impact extreme precipitation, at both event annual scales, on CZ within semiarid site vegetated apple trees China's Loess Plateau. At scale, vapor flux was two orders magnitude lower than liquid water flux. However, thermal penetrated depths 200 cm, whereas isothermal only infiltrated 100 cm during study period, implying that thermal‐gradient‐driven is an important mechanism for deep‐layer recharge (DLR). DLR below extremely wet years 6.5 times larger dry years. In contrast, changes climate had limited impacts evapotranspiration; difference between averaged 35 mm, much less 310 mm. showed higher ratio (0.58) transpiration evapotranspiration did (0.51). findings reported improve our understanding related regions.

Language: Английский

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A SIF-based approach for quantifying canopy photosynthesis by simulating the fraction of open PSII reaction centers (qL)

Remote Sensing of Environment, Journal Year: 2024, Volume and Issue: 305, P. 114111 - 114111

Published: March 16, 2024

Advances in retrieval of solar-induced chlorophyll fluorescence (SIF) provide a promising and independent approach for quantifying gross primary production (GPP) across spatial scales. Recent studies have highlighted the prominent role qL, fraction open Photosystem II (PSII) reaction centers, mechanistically modeling GPP from remote sensing SIF. However, due to limited availability simulated experimental data, comprehensive understanding qL responses environmental physiological variations has yet emerge, as consequence, prediction leaf canopy scales is still an early stage. Based on global sensitivity analysis recently developed mechanical model photosynthesis, we find that broadband total SIF emitted PSII (SIFTOT_FULL_PSII) temperature (TLeaf) are two major predictors qL. A leaf-level instrument designed obtain concurrent measurements SIFTOT_FULL_PSII, TLeaf over wide range conditions. From these measurements, show can be modelled hyperbolic function SIFTOT_FULL_PSII with only one temperature-related parameter m which increases temperature, but decreases rapidly temperatures exceed optimum temperature. It suggested mathematically by peaked function. The results experiments winter wheat demonstrate proposed predicts high accuracy (R2 ≥ 0.91, rRMSE ≤ 8.46%) under diverse light essential steps necessary apply it at scale, including estimating escape fraction, removing I, reconstructing top-of-canopy (TOC) narrowband SIF, also presented. Our confirm estimated using SIF-informed agrees well measured site = 0.81, 12.03%). key benefit provides critical information collective influence sub-canopy environment avoiding requirement explicitly estimate different depths, potentially promoting ability quantify photosynthetic CO2 assimilation large

Language: Английский

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Coupled Snow and Frozen Ground Physics Improves Cold Region Hydrological Simulations: An Evaluation at the upper Yangtze River Basin (Tibetan Plateau)

Journal of Geophysical Research Atmospheres, Journal Year: 2019, Volume and Issue: 124(23), P. 12985 - 13004

Published: Nov. 28, 2019

Abstract Cryosphere plays an important role in cold‐region (e.g., Tibetan Plateau) hydrological processes under climate change, and thus cryosphere physics should be carefully represented the modeling. In this study, based on Water Energy Budget‐based Distributed Hydrological Model (WEB‐DHM), we have further improved processes, by incorporating enthalpy‐based coupled snow frozen ground (hereinafter WEB‐DHM‐SF), comprehensively evaluated at upper Yangtze River Basin widespread cover ground. The model was calibrated validated basin scale using observed discharge Zhimenda station during 1981–2016 simulated with high accuracies. also successfully reproduced basin‐wide daytime nighttime land surface temperature (LST) as well depth basin‐averaged time series spatial distributions. At point scale, soil moisture profiles Tuotuohe available yearlong observations. Furthermore, experiments were designed to investigate improvements indicated that incorporation of three‐layer scheme correct consideration incident solar radiation attenuation among layers resulted lowered melting reduced discharges. Additionally, a description water phase changes rendered modeled moistures temperatures more accurate cold season. Through rigorous evaluations performance, demonstrates significant promise for improving simulations river basins TP.

Language: Английский

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Effect of freeze–thaw cycling on the soil‐freezing characteristic curve of five Canadian soils

Vadose Zone Journal, Journal Year: 2020, Volume and Issue: 19(1)

Published: Jan. 1, 2020

Abstract The frozen soil processes and their interaction with the environment in vadose zone of cold regions is vital both agricultural engineering practice applications. In a soil, unfrozen water pore ice coexist. relationship between content subzero temperature widely known as soil‐freezing characteristic curve (SFCC). SFCC valuable tool for predicting hydromechanical properties modeling coupled thermal–hydraulic–mechanical–chemical process soils. spite its importance, effect freeze–thaw (F–T) cycling on has not been well investigated or understood. this technical note, F–T cycles five soils from Canada were investigated. (including freezing thawing branches) different measured using frequency domain reflectometry (FDR) technique. experimental results suggest that significant. Such behavior may be attributed to destruction structure during saturation process. However, all soils’ exhibited hysteresis cycles. study are contribute towards better understanding fundamental various region

Language: Английский

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