Wei Feng

• Professor
• Professor at Sun Yat-sen University

Limited by the number and location distribution of ground stations, the ground based ionospheric detection using Global Navigation Satellite Systems (GNSS) technology suffers from low accuracy and poor reliability in some regions. To improve the performance of the global ionospheric model, this study combines the Continuously Operating Reference St...

Influenced by various geophysical factors, gravity and bathymetry exhibit significant correlations only at certain intermediate wavelengths. In this study, a deep neural network (DNN) combined with multi-source gravity data was used to recovery the intermediate wavelength (15–160 km) depth in the Sea of Japan (37–42°N, 130–138°E), to analyze the co...

The gravity–geologic method (GGM) is widely used for bathymetric predictions. However, the conventional GGM cannot be applied in regions without actual bathymetric data. The modified gravity–geologic method (MGGM) enhances the accuracy of bathymetric models by supplementing short-wavelength gravity anomalies with an a priori bathymetric model, but...

Accurate Digital Elevation Models (DEMs) are essential for precise terrain gravity field calculations, which are critical in gravity field modeling, airborne gravimeter and gradiometer calibration, and geophysical inversion. This study evaluates the accuracy of various satellite DEMs by comparing them with a LiDAR DEM at the Wudalianchi test site,...

The Gravity Recovery and Climate Experiment (GRACE) satellites have observed mass migrations caused by megathrust earthquakes. Extracting earthquake-related signals from GRACE data is still a challenge due to the interference from non-earthquake sources such as terrestrial hydrology. Instead of reducing hydrological signals by potentially biased hy...

The Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) missions have enabled consistent production of monthly gravity field solutions by international institutes, contributing to the International Centre for Global Earth Models. Each institute employs distinct processing strategies, yielding varied estimates of terrestri...

The ocean tide loading (OTL) can result in displacements of centimeters or even decimeters at nearshore stations. Global ocean tide models exhibit errors in nearshore regions, which limit the accuracy of maintaining the coordinates of these stations. GNSS positioning can obtain tidal load displacements in nearshore areas, but it often requires long...

A global gravity field model (GGM) is essential to be validated with ground-based or airborne observational data for the accurate application of the GGM at a regional scale. Furthermore, accurately understanding the commission errors between the GGM and observational data are crucial for improving regional gravity fields. Taking the North China reg...

The gravity and gradient anomalies contain valuable information about the underground geological structures at various depths. Deep and shallow buried source bodies are able to be identified through multi-scale field separation processes, and visual comprehensions of geological structures can be obtained via 3D density inversion techniques. In this...

Fast and reliable cycle slip determination can ensure successive ambiguity resolution and precise positioning. Generally, it is not difficult to determine big cycle slips using the linear combination of observations, for instance, the geometry-free (GF) combination and the Hatch-Melbourne-Wübbena (HMW) combination. However, the participation of pse...

Detecting earthquake-induced bathymetric changes helps to understand the geomorphologic process of tufa lakes. Traditional field measurement methods are difficult for spatially complete and continuous bathymetric mapping. Multi-temporal high-resolution optical satellite images are cost-efficient data used for bathymetric change detection. However,...

The high-frequency gravity forward modeling relying on the residual terrain modelling (RTM) technique, is essential for gravity data processing, fine gravity field modeling, geophysical inversion and etc. However, classical gravity forward modelling methods face challenges like series divergence and inefficient computation. To improve the computati...

Assessing changes in freshwater availability accurately is crucial for societal development. Previous studies have examined long‐term variations in basin‐scale terrestrial water storage (TWS) using Gravity Recovery and Climate Experiment (GRACE) mission data. However, different basins exhibit distinct spatial and temporal TWS variation patterns. To...

The “non-harmonicity” problem in residual terrain modelling (RTM) is a challenging issue, causing errors exceeding 200 mGal in the RTM gravity anomaly in rugged areas. Although various methods have been proposed to address this problem, including the condensation method, regularized downward continuation methods with Taylor series expansions (TS) a...

Modern geodetic technologies, including high-precision ground-based gravity measurements, satellite gravimetry, satellite altimetry, Global Navigation Satellite Systems (GNSS), and Interferometric Synthetic Aperture Radar(InSAR), offer a wealth of observations for monitoring global hydrological processes with exceptional accuracy and spatio-tempora...

The increased number of satellites and stations leads to the serious time consumption of the integrated precise orbit determination (POD), especially in the current global navigation satellite system (GNSS) with more than 120 satellites. To improve the computational efficiency of multi-GNSS-integrated POD, this paper proposed an improved parameter...

The "non-harmonicity" problem, as one of the main problems in the residual terrain modelling (RTM) method, would involve more than 200 mGal errors in the gravity field determination over the Himalaya area. To deal with it, there are five main harmonic correction (HC) methods, i.e., the condensation method, regularized downward continuation method w...

Terrestrial water storage (TWS) is a critical component for sustainable societal development and ecosystem cycles. The Gravity Recovery and Climate Experiment satellites have tracked changes in global TWS under the combined effects of various factors with unprecedented accuracy since 2002. In this study, we separate the trends in TWS driven by prec...

In the study of volcanism, other than seismic and magnetotelluric surveys, gravity survey is also an effective way to study the subsurface geological structures and materials composition. Gravity anomalies can imply the anomalous bodies with unique densities, like mineral deposits, magmas, faults, etc. Based on terrestrial gravimetry, density struc...

California's Central Valley, one of the most agriculturally productive regions, is also one of the most stressed aquifers in the world due to anthropogenic groundwater over-extraction primarily for irrigation. Groundwater depletion is further exacerbated by climate-driven droughts. Gravity Recovery and Climate Experiment (GRACE) satellite gravimetr...

Citation: Chen, W.; Shum, C.K.; Forootan, E.; Feng, W.; Zhong, M.; Jia, Y.; Li, W.; Guo, J.; Wang, C.; Li, Q.; et al. Understanding Water Level Changes in the Great Lakes by an ICA-Based Merging of Multi-Mission Altimetry Measurements. Remote Sens. 2022, 14, 5194. https://doi.

Hydrological droughts are events of prolonged water scarcity and cause many devastating impacts. It is, therefore, extremely crucial to understand their spatiotemporal evolution to guide prevention and mitigation policies. The Gravity Recovery and Climate Experiment (GRACE, April 2002-June 2017) and GRACE Follow-On (GRACE-FO, June 2018-present) mis...

This GIF illustrates the testing GRACE(-FO) TWSA fields, BCNN's reconstructions and predictive uncertainties (std)

Technological advances in global navigation satellite system (GNSS) offer a novel environmental sensor to measure terrestrial water cycles and provide independent constraints on total terrestrial water storage (TWS) changes over various spatiotem-poral scales. This study aims to develop an open-source MATLAB-based tool for inferring daily TWS chang...

The increased number of satellites and stations expands the dimensions of the normal equation system (NEQ), which lead to the serious time consumption of the integrated precise orbit determination (POD), especially in the current Global Navigation satellite system (GNSS) with more than 120 satellites. To improve the computational efficiency of mult...

Groundwater is a key component of the global hydrological cycle. Quantitative approaches to estimate the spatial and temporal changes in groundwater storage (GWS) could provide solid foundation for sustainable management. This study made a comprehensive comparison of GWS changes based on two independent approaches: the Soil and Water Assessment Too...

The hydrological loading displacements measured by continuous Global Navigation Satellite System (GNSS) networks can provide critical constraints on total terrestrial water storage (TWS) anomalies. We invert sparsely distributed GNSS vertical positions for daily large-scale water heights based on Slepian basis functions and devise a novel GNSS-base...

Zhengzhou and its surrounding areas, located in northern Henan Province, China, receive continuous extreme rainfall from July 17 to July 22, 2021. Northern Henan Province experiences extensive flash floods and urban floods, causing severe casualties and property damage. Understanding the variation of hydrologic features during this flood event coul...

The monthly terrestrial water storage anomaly (TWSA) observations during the gap period between the Gravity Recovery and Climate Experiment (GRACE) satellite and its Follow-On (GRACE-FO) are missing, leading to discontinuity in the time series, and thus, impeding full utilization and analysis of the data. Despite previous efforts undertaken to tack...

Arid regions of Central Asia have sensitive ecosystems that rely heavily on terrestrial water storage which is composed of surface water storage, soil moisture storage and groundwater storage. Therefore, we employed three Gravity Recovery and Climate Experiment (GRACE) satellite datasets and five global hydrological models (GHMs) to explore the ter...

There is an approximately one-year observation gap of terrestrial water storage anomalies (TWSAs) between the Gravity Recovery and Climate Experiment (GRACE) satellite and its successor GRACE Follow-On (GRACE-FO). This poses a challenge for water resources management, as discontinuity in the TWSA observations may introduce significant biases and un...

In the summer and autumn of 2019, the extreme drought in the middle and lower reaches of the Yangtze River lasted for half a year, which had a serious impact on local agricultural production and ecological environment. At present, the estimation of drought degree mainly depends on the monitoring of precipitation, evapotranspiration, runoff and soil...

The differential code and phase biases induced by the receiver hardware (including receiver, antenna, firmware, etc.) of the Global Navigation Satellite System (GNSS) have significant effects on precise timing and ionosphere sensing, thus deserve careful treatment. In this contribution, we propose an approach to fast fix the single-difference ambig...

The Gravity Recovery and Climate Experiment (GRACE) data have been extensively used to evaluate the total terrestrial water storage anomalies (TWSA) from hydrological models. However, which individual water storage components (i.e., soil moisture storage anomalies (SMSA) or groundwater water storage anomalies (GWSA)) cause the discrepancies in TWSA...

We developed a new boundary-included inversion model to improve the terrestrial water storage (TWS) inverted from regional GPS vertical deformation data. Through defining a new disc load empirical function (DLEF) and considering the mass change effect from the near but outside region, the result shows the TWS is more reasonable than the one inverte...

Terrestrial water storage (TWS) can be influenced by both climate change and anthropogenic activities. While the Gravity Recovery and Climate Experiment (GRACE) satellites have provided a global view on long-term trends in TWS, our ability to disentangle human impacts from natural climate variability remains limited. Here we present a quantitative...

In this paper, we robustly analyze the noise reduction methods for processing spherical harmonic (SH) coefficient data products collected by the Gravity Recovery and Climate Experiment (GRACE) satellite mission and devise a comprehensive GRACE Matlab Toolbox (GRAMAT) to estimate spatio-temporal mass variations over land and oceans. Functions in GRA...

The Yangtze River Basin is an important economic area in China. Monitoring TWS change in this basin is strongly meaningful for exploitation of water resources and economic development. Filtering is necessary to derive the TWS from GRACE time-variable gravity field models, but the signal is distorted. Therefore, we subtract the leakage error from th...

GRACE temporal gravity field solutions have been widely used for hydrologic related research. Generally, two forms of mathematical representations of GRACE solutions, the spherical harmonic solution (Level 2 or L2 data products), and the constrained mascon solutions are more popular and their respective data products are publicly available. Spheric...

GRACE temporal gravity field solutions have been widely used for hydrologic related research, e.g. terrestrial water storage variation, ground water depletion, drought and flood. Generally, two forms of GRACE solutions, unconstrained spherical harmonic solution (L2) and constrained mascon solution, published by three official institutions JPL, CSR...

Groundwater plays a critical role in the global water cycle and is the drinking source for almost half of the world’s population. However, exact quantification of its storage change remains elusive due primarily to limited ground observations in space and time. The Gravity Recovery and Climate Experiment (GRACE) twin-satellite data have provided gl...

The West Liaohe River Basin (WLRB) is one of the most sensitive areas to climate change in China and an important grain production base in the Inner Mongolia Autonomous Region of China. Groundwater depletion in this region is becoming a critical issue. Here, we used the Gravity Recovery and Climate Experiment (GRACE) satellite data and in situ well...

Identity gravity change signals caused by 2008 South China snow/ice storm and 2010 North America snow storm from GRACE solutions.

Since 1993, the Global Mean Sea Level (GMSL) has been rising at a rate of about 3 mm/yr detected by multi-satellite radar altimetry. The spaceborne gravimetry satellite, Gravity Recovery and Climate Experiment, GRACE, has been monitoring Earth’s surface water mass variations since 2002. La Niña and El Niño events induces inter-annual variations of...

unpublished paper Argo;Aviso;GRACE;global sea level rise; Ocean mass change; steric sea level rise; ENSO

Total sea level variations (SLVs) are caused by two major components: steric variations due to thermal expansion of seawater, and mass-induced variations due to mass exchange between ocean and land. In this study, the global SLV and its steric and mass components were estimated by satellite altimetry, Argo float data and the Gravity Recovery and Cl...

The Gravity Recovery and Climate Experiment (GRACE) mission can significantly improve our knowledge of the temporal variability of the Earth's gravity field. We obtained monthly gravity field solutions based on variational equations approach from GPS-derived positions of GRACE satellites and K-band range-rate measurements. The impact of different f...

The Red Sea is a semi-enclosed basin and exchanges water with the Gulf of Aden through the strait of Bab-el-Mandeb at the southern part of the sea. Its circulation is affected by the Indian Monsoon through its connection via the Gulf of Aden. Two distinctive (in summer and in winter) seasonal signals represent the water exchange. To understand the...

An annual amplitude of ∼18 cm mass-induced sea level variations (SLV) in the Red Sea is detected from the Gravity Recovery and Climate Experiment (GRACE) satellites and steric-corrected altimetry from 2003 to 2011. The annual mass variations in the region dominate the mean SLV, and generally reach maximum in late January/early February. The annual...

Changes in regional groundwater storage in North China were estimated from the Gravity Recovery and Climate Experiment (GRACE) satellites data and ground-based measurements collected from 2003 to 2010. The study area (˜370,000 km2) included the Beijing and Tianjin municipality, the Hebei and Shanxi province, which is one of the largest irrigation a...

Sea level variations (SLVs) can be divided into two major components: the steric SLV and the mass-induced SLV. These two components of SLV in the South China Sea (SCS) are studied by using satellite altimetry, GRACE (Gravity Recovery and Climate Experiment) satellite gravity, and oceanographic data on annual and inter-annual timescales. On the annu...

We have analyzed mass-induced sea level variations (SLVs) in the Red Sea from steric-corrected altimetry and GRACE between January 2003 and December 2010. The steric component of SLVs in the Red Sea calculated from climatological temperature and salinity data is relatively small and anti-phase with the mass-induced SLV. The total SLV in the Red Sea...