Gang Li

• Ph.D
• Professor (Associate) at Sun Yat-sen University

Real-Time/Post-Processing Kinematic (RTK/PPK) technology has been widely applied in Unmanned Aerial Vehicle (UAV) photogrammetry in glaciological research. Considering that ground control points (GCPs) cannot be set on glaciers, evaluating the impacts of one-sided distribution is essential. In this study, 8571 images were captured at Sermeq Avannar...

The challenges of utilizing the 250-m resolution thermal infrared (TIR) data obtained from the Medium Resolution Spectral Imager-II (MERSI-II) onboard the Chinese Fengyun-3D (FY-3D) satellite are bowtie effect and non-uniform brightness stripe noise. While previous solutions have addressed these issues separately, this manuscript introduced a more...

Sea ice drift is a crucial parameter for sea ice flux, atmospheric and ocean circulation, and ship navigation. Pattern matching is widely used to retrieve sea ice drift from Synthetic Aperture Radar (SAR) data, but it often yields mismatched vectors and coarse spatial resolution. This study presents a framework to enhance the spatial resolution and...

A R T I C L E I N F O Keywords: Glacier velocity Sentinel-1 Sentinel-2 Greenland ice sheet Offset-tracking SBAS A B S T R A C T Synthetic Aperture Radar (SAR) images are commonly used to monitor glacier flow velocity at Greenland Ice Sheet (GrIS). However, offset-tracking with SAR imagery in summer usually show poor quality because the rapid ice su...

Moderate-resolution optical imagery holds great potential in deriving Arctic sea ice drift fields because of its higher resolution than microwave radiometers and scatterometers, as well as its larger swath widths than most other optical and synthetic aperture radar (SAR) images. However, the application of such imagery is hindered by cloud influenc...

Offset-tracking is more commonly used in monitoring glacier velocity at Greenland Ice Sheet (GrIS) than the D-InSAR technique because of its robustness in handling low coherence and unnecessary of phase unwrapping. Large deformation rates of polar glaciers can cause a deformation gradient which exceeds the theoretical limitation of phase unwrapping...

Rising sea level caused by global climate change may increase extreme sea level events, flood low-lying coastal areas, change the ecological and hydrological environment of coastal areas, and bring severe challenges to the survival and development of coastal cities. Hong Kong is a typical economically and socially developed coastal area. However, i...

Accurate extraction of urban impervious surface (UIS) is essential for urban planning and environmental monitoring. However, multispectral remote sensing data for UIS extraction suffers from the inter-class spectral confusions, e.g. UIS and bare soil, and intra-class variations of sub-class UIS. Hyperspectral and full/dual-polarization synthetic ap...

The backscatter coefficients of Synthetic Aperture Radar (SAR) images that observe the Greenland Ice Sheet (GrIS) are incidence angle dependent, which impedes subsequent applications, such as monitoring its surface melting. Therefore, backscatter intensities with varying incidence angles should be normalized. This study proposes an incidence angle...

Applying feature tracking techniques to synthetic aperture radar (SAR) imagery generates high-resolution sea ice motion fields. However, the bad matching vectors still exist after the Nearest Neighbor Distance Ratio test and contaminate the derived motion fields, which need to be identified and filtered out. In this article, we propose two algorith...

Vegetation is a land-use type that attracting growing attention in urban studies. Extraction of urban vegetation information can be achieved by land-use/land-cover (LULC) classification. It has been proved that SAR remote sensing provides complementary information in LULC classification. However, how the complementary information from SAR features...

Bistatic SAR interferometry is an essential technique of observing glacier height changes and geodetic mass balance. Eastern Nyainqentanglha distributes the majority parts of monsoonal temperate glaciers and presented the quickest glacier mass loss rate at High-mountains Asia. Most recent studies on glacier mass balance at High-mountains Asia focus...

Numerous studies on environmental modeling and ecological process lay emphasis on the fundamental information of the impervious surface area (ISA). However, accurate ISA extraction from high-resolution satellite images remains challenging due to both the high diversity of land covers and shadow effects from tall buildings and trees. To address the...

Short-term characteristics of urban land cover change have been observed and reported from satellite images, although urban landscapes are mainly influenced by anthropogenic factors. These short-term changes in urban areas are caused by rapid urbanization, seasonal climate changes, and phenological ecological changes. Quantifying and understanding...

Mangrove forests are the most productive ecosystem for tropical and subtropical flora, but they are experiencing serious loss. Urgent measures should be taken for conservation and restoration, including investigation of mangrove species constitution using satellite imagery in which texture provides effective information. However, differentiation by...

Remote sensing based geodetic observations can be used as alternatives data to map glacier height changes because the harsh environment complicates in situ observations. In this study, we analysed five pairs of X-band bistatic TerraSAR-X/TanDEM-X images from 2011 and 2014 for Mt. Everest (Qomolangma). Glacier height changes were derived using the D...

In contrast to the glacier mass losses observed at other locations around the world, some glaciers in the High Mountains of Asia appear to have gained mass in recent decades. However, changes in digital elevation models indicate that glaciers in Karakoram and Pamir have gained mass, while recent laser altimetry data indicate mass gain centred on We...

Spaceborne Synthetic Aperture Radar (SAR) interferometry has been utilised to acquire high-resolution Digital Elevation Models (DEMs) with wide coverage, particularly for persistently cloud-covered regions where stereophotogrammetry is hard to apply. Since the discovery of sand buried drainage systems by the Shuttle Imaging Radar-A (SIR-A) L-band m...

The Western Nyainqentanglha Range locates in the southeastern center of the Inner Tibetan Plateau (ITP). Glaciers in this region are influenced by both the continental climate of Central Asia and the Indian Monsoon system. Their melting on the western slopes feeds the Nam Co Lake, which is the second largest endorheic lake in the ITP. The elevation...

With the increasing applications of multisource remote sensing, the synergistic use of optical and Synthetic Aperture Radar (SAR) remote sensing images is becoming increasingly popular. Although numerous approaches have been proposed to register satellite images between two optical images or between two SAR images, these approaches cannot be direct...

Geladandong Ice Field is one of the largest ice fields in central Qinghai-Tibetan Plateau, also the water source of Yangtze River, Selin Co Lake and Chibozhang Co Lake. In this study, we aim to monitor the glacier flow rates and its change in 1990s and 2000s by Differential SAR Interferometry and offset tracking. We obtained SAR images acquired by...

We used two Envisat images from ESA to reveal the co-seismic deformation field caused by the Mw7. 1 earthquake in eastern Turkey on Oct. 23, 2011, and a linear elastic dislocation model in half space to estimate the corresponding fault geometry, location, and displacement. The result indicates that the earthquake is caused mainly by a buried thrust...

We obtained several displacement time series from the Sichuan permanent GPS net and processed the 1-Hz data observed during a few days before the 2008 Ms8.0 Wenchuan earthquake by double-difference instantaneous positioning technique. We filtered the data by the spatial stacking and the modified sidereal filtering methods to reduce correlation bias...

Roving and permanent GPS survey in Tibetan Plateau provide adequate data for crustal deformation study, which demonstrate the collision of Eurasia Plate and India Plate, uplift of Tibetan Plateau. Most GPS sites within Tibetan Plateau show a significant positive vertical velocity, however, others show subsidence. We noticed that most sites show neg...