A5069344383- Cryospheric studies and observations
- Climate change and permafrost
- Arctic and Antarctic ice dynamics
- Soil Moisture and Remote Sensing
- Precipitation Measurement and Analysis
- Meteorological Phenomena and Simulations
- Landslides and related hazards
- Urban Heat Island Mitigation
- Climate variability and models
- Flood Risk Assessment and Management
- Hydrology and Watershed Management Studies
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Power Systems and Technologies
- Winter Sports Injuries and Performance
- Advanced Chemical Physics Studies
- Geophysics and Gravity Measurements
- Wind and Air Flow Studies
- Aerospace Engineering and Energy Systems
- Remote Sensing and LiDAR Applications
- Molecular Spectroscopy and Structure
- Smart Materials for Construction
- Environmental Changes in China
- Spacecraft Design and Technology
- Tree Root and Stability Studies
- Soil Mechanics and Vehicle Dynamics
Chinese Academy of Sciences
2011-2024
State Key Laboratory of Remote Sensing Science
2009-2024
Aerospace Information Research Institute
2019-2024
National Space Science Center
2023-2024
China Meteorological Administration
2024
Beijing Normal University
2009-2022
Shantou University
2022
Shantou University Medical College
2022
The Ohio State University
1998-2021
Institute of Remote Sensing and Digital Earth
2018-2020
Snow cover is highly critical for global water and energy cycles because of its wide areal extent, high reflectivity good thermal insulation. Knowledge snow conditions, e.g., equivalent (SWE) depth, significant to hydrologic climatologic processes. Spaceborne passive microwave (PMW) data, namely, brightness temperature (TB), have been in use depth SWE retrieval at the scale since 1978. However, sensitivity TB these parameters complex due metamorphism (e.g., grain size, GS), which limits...
Abstract. We investigated the potential capability of random forest (RF) machine learning (ML) model to estimate snow depth in this work. Four combinations composed critical predictor variables were used train RF model. Then, we utilized three validation datasets from out-of-bag (OOB) samples, a temporal subset, and spatiotemporal subset verify fitted algorithms. The results indicated following: (1) accuracy is greatly influenced by geographic location, elevation, land cover fractions; (2)...
Abstract There has been a statement that the satellite and reanalyses significantly overestimate snow depths (SDs) as compared with in-situ observations over Tibetan Plateau (TP). The inconsistency may be partly due to representations related different spatial resolutions. To further clarify matters of scale, this work estimates compares fractional cover (FSC) from MODIS (500 m), SDs Sentinel-1 C-band SAR (1 km), ERA5-Land (9 km) ERA5 (31 together ground GHCN-D at 6 newly-established...
Soil freeze-thaw cycles have a profound impact on heat and water fluxes at the land-atmosphere interface transport in soils. Microwave remote sensing is widely used technique to detect near-surface soil freeze/thaw states due significant changes dielectric properties associated with phase transitions soils, where uncertainty remains. This letter proposes new parameterization scheme for estimation of unfrozen content improve modeling during transitions. Predictions from model referred as...
The spatiotemporal distribution of snow depth (SD) has a significant impact on the energy and water balances Earth's system. However, passive microwave remote sensing widely used for SD estimation large uncertainties due to variations in physical properties. In this study, we demonstrate new method minimize these increase accuracy estimation. Our is based synergy between AMSR-2 brightness temperature (TB) process model (SNTHERM) estimate grain size, density first-guess as priors. On one...
Abstract. Accurate long-term daily cloud-gap-filled fractional snow cover products are essential for climate change and hydrological studies in the Asian Water Tower (AWT) region, but existing Moderate Resolution Imaging Spectroradiometer (MODIS) not sufficient. In this study, multiple-endmember spectral mixture analysis algorithm based on automatic endmember extraction (MESMA-AGE) multistep spatiotemporal interpolation (MSTI) used to produce MODIS product over AWT region (AWT FSC). The FSC...
Abstract. Water storage in snowpacks mountain areas is critical for hydropower production, hydrological forecasting, and freshwater availability. Spaceborne synthetic aperture radar (SAR) a powerful tool quantitatively measuring snow mass because of its high spatial resolution the sensitivity signals to depth (SD). In particular, first SAR SD product (C-snow) based on Sentinel-1 satellites displays depolarization dynamic monitoring mountainous areas. Moreover, upscaled C-snow retrievals...
Microwave emission models are a critical component of snow water equivalent retrieval algorithms applied to passive microwave measurements. Several such exist, but their differences need be systematically compared. This paper compares the basic theories two models: multiple-layer Helsinki University Technology (HUT) model and layered snowpacks (MEMLS). By comparing mathematical formulation side by side, three major were identified: 1) assuming that scattered intensity is mostly (96%) in...
Abstract. Radar at high frequency is a promising technique for fine-resolution snow water equivalent (SWE) mapping. In this paper, we extend the Bayesian-based Algorithm SWE Estimation (BASE) from passive to active microwave (AM) application and test it using ground-based backscattering measurements three frequencies (X- dual Ku-bands, 10.2, 13.3 16.7 GHz), VV polarization obtained 50° incidence angle Nordic Snow Experiment (NoSREx) in Sodankylä, Finland. We assume only an uninformative...
Abstract Most climate models show systematic cold biases during snow‐covered period over the Tibetan Plateau (TP), which is associated with snow and surface albedo overestimations. In this work, a cover fraction (SCF) scheme recently developed for shallow are implemented in Noah‐MP land model coupled Weather Research Forecasting (WRF) model. The SCF introduces subgrid orographic variability to reduce SCF, shallow‐snow parameterizes fresh‐snow as function of depth (SD). Evaluations by remote...
In cold regions, the coexistence and interconversion of liquid water ice in frozen soils have important implications for energy partitioning surface runoff at Earth's surface. Passive microwave remote sensing is crucial global monitoring soil moisture (SM). However, current research on SM focuses mainly unfrozen conditions. Limited studies been conducted variations content throughout freezing season. This study investigated potential use brightness temperature (TB) observations from Soil...
Snow depth estimation with passive microwave (PM) remote sensing is challenged by spatial variations in the Earth’s surface, e.g., snow metamorphism, land cover types, and topography. Thus, traditional static retrieval algorithms cannot capture thickness well. In this study, we present a new operational algorithm, hereafter referred to as pixel-based method (0.25° × 0.25° grid-level), provide more accurate nearly real-time estimates. First, reference was retrieved using previously proposed...
Snow density varies spatially, temporally, and vertically within the snowpack is key to converting snow depth water equivalent. While previous studies have demonstrated feasibility of retrieving using a multiple-angle L-band radiometer in theory ground-based experiments, this technique has not yet been applied satellites. In study, was retrieved Soil Moisture Ocean Salinity (SMOS) satellite observations at 43 stations Quebec, Canada. We used one-layer radiative transfer model added τ-ω...
Snow depth or snow water equivalent in mountainous region is crucial for hydrology, resources management, meteorological and climate research. Remote sensing can be used monitoring regional scale global scale. However, the spaceborne remote of mountain challenging because sensor sensitivity spatial resolution problems. Recently, time series Sentinel-1 retrieval mountains, which shows encouraging accuracy. In this study, an algorithm to estimate regions using optical passive microwave...
A physical-statistical framework to estimate Snow Water Equivalent (SWE) and depth (SD) from SAR measurements was implemented applied SnowSAR flight-line data collected during the SnowEx'2017 field campaign in Grand Mesa, Colorado, USA averaged 90 m resolution. The physical (radar) model is used describe relationship between snowpack conditions volume backscatter. statistical a Bayesian inference that seeks joint probability distribution of backscatter measurements, SWE SD parameters. To...
Abstract. Radar at high frequency is a promising technique for fine-resolution snow water equivalent (SWE) mapping. In this paper, we extend the Bayesian-based Algorithm SWE Estimation (BASE) from passive to active microwave (AM) application and test it using ground-based backscattering measurements three frequencies (X dual Ku bands; 10.2, 13.3, 16.7 GHz), with VV polarization obtained 50° incidence angle Nordic Snow Experiment (NoSREx) in Sodankylä, Finland. We assumed only an...
Validation of the snow process model is an important preliminary work for parameter estimation. The grain growth a continuous and accumulative process, which cannot be evaluated without comparing with observations in season scale. In order to understand properties Asian Water Tower region (including Xinjiang province Tibetan Plateau) enhance use modeling tools, extended experiment at foot Altay Mountain was designed validate improve coupled physical Snow Thermal Model (SNTHERM) Microwave...
The snow water equivalent (SWE, a measurement of the amount contained in packs) is an important variable earth systems. Microwave remote sensing provides possible solution for estimating SWE globally. To support radar retrieval, backscattering theory needs to be studied; forward simulation model validated against natural observations. In this study, one-winter experiment observe time series coefficient snow-covered bare soil reported. This first long that was measured by imaging radar....
The cyclic molecule ethylene oxide (c-C2H4O) has recently been detected in the interstellar source Sgr B2N. Previous laboratory work on rotational spectrum of this extends only to a frequency 123 GHz. We report here extension species through range 262-358 GHz using new fast scan spectrometer (FASSST). newly measured lines have combined with previous data at lower frequencies form set consisting 662 that assigned and fitted via standard semirigid asymmetric top analysis. spectral constants...
Dense media radiative transfer theory (DMRT) is used to study the multiple scattering effects in active microwave remote sensing. To solve dense equation, we decompose diffuse intensities into Fourier series azimuthal direction. Each harmonic solved by eigen-quadrature approach. The solution includes full within DMRT. Comparisons are made with first order and second solutions. model applied sensing of terrestrial snow. Full important as optical thickness for snow often exceed unity. results...
Snow-depth retrieval from passive microwave observations without a priori information is highly undetermined problem. Achieving accurate snow-depth retrievals requires on the snowpack properties, such as grain size, density, physical temperature, and stratigraphy. On practical level, however, algorithms must consider prior information, while minimizing dependence it, ancillary data are not globally available. In this study, we build previously published Bayesian Algorithm for Snow Water...