Fuyuan Liang

• Western Illinois University

Conventionally urban structures are mainly inferred from the spatial arranges of related urban elements such as land use and population density. China's unprecedented urbanization process has significantly changed urban spatial structure and it is not clear how urban structure impacts the sustainability and livability of cities across a large geogr...

Intense human activities have disintegrated continuous habitats to smaller patches and subsequently pose threats to ecological safety. The Qinghai-Tibet Plateau (QTP) is a prestigious reserve for many high-plateau wild life species and its fragile ecological environment is under increased pressure of human activities. It is not clear how short-term...

China shares its board with one developed and thirteen developing countries. A timely, precise, and efficient socioeconomic study of border regions is vital for evaluating political problems and identifying potential economic prospects. Usually, conventional socioeconomic statistical data suffer from significant time lags and unequal statistical sc...

Extreme weather events become more frequent in the context of global climate change. Understanding how the public sense and perceive extreme weather events such as rainstorms is crucial for rainstorm-induced hazard mitigation. However, it is not clear how public's rainstorm perception and sensitivity vary across a large geographic scale. In this st...

The disaster-relevant authorities could make an uninformed decision due to the lack of a clear picture of the urban resilience to adverse natural events. Previous studies seldom examine the near-real-time human dynamics, which are critical to disaster emergency response and mitigation, in response to the development and evolution of a natural hazar...

Matupi Cave, near the equator at 1.2°N in the northeastern Democratic Republic of the Congo, is in an inland region of equinoctial (March–May and August–November) rainfall distinct from summer rainfall to the north (e.g., in the Sahara) and to the south. Investigation of one entire stalagmite, parts of two others, and a core through a fourth from M...

Every year typhoons severely disrupt the normal rhythms of human activities and pose serious threats to China’s coast. Previous studies have shown that the impact extent and degree of a typhoon can be inferred from various geolocation datasets. However, it remains a challenge to unravel how dwellers respond to a typhoon disaster and what they conce...

Climate change and human socioeconomic activities both strongly impact long-term vegetation greenness. It is more a challenge to evaluate the impacts of socioeconomic activities on vegetative greenness than climate change, partially due to the lack of appropriate quantitative indicators of the former. Here we examined the relationship between the r...

Fine-scale population datasets are essential to many health and development applications. Quite a few population estimate approaches have been proposed and multiple gridded population datasets have been produced. However, it is still a challenge to accurately estimate daily and even hourly population dynamics. In this study, we present an ensemble...

The 4.2 ka Event has generally been regarded as a period of decades to at most a few centuries in which comparatively dry conditions existed in the Middle East and more broadly across the mid-latitude Northern Hemisphere. This paper presents new stable-isotopic and petrographic observations from two previously-unreported U-Th-dated stalagmites from...

Mobile internet and wireless communication technologies have produced unprecedented location-aware data. Such big geospatial data can be used as a proxy measure of the ‘digital footprints’ left by us on the planet and provide a valuable opportunity to understand the dynamic and short-term human disturbance on the nature at fine scales. This study i...

Location-aware big data from social media have been widely used to study functions of different zones in a city but not across a city as a whole. In this study, a novel framework is proposed to quantify city-level dynamic functions of 200 cities in China from a perspective of collective human activities. The random forest model was used to determin...

Real-word phenomena, such as ocean eddies and clouds, tend to split and merge while they are moving around within a space. Their trajectories usually bear one or more branches and are accordingly defined as complex trajectories in this study. The trajectories may show significant spatiotemporal variations in terms of their structures and some of th...

Stalagmite ANJ94-2 from Anjohibe Cave in northwestern Madagascar provides an exceptionally detailed and precisely dated record of changing environmental conditions that, combined with previously published data from stalagmites, wetland deposits, and archaeological sites, allows insights into past climate change, human environmental impact, and mega...

Many real-world dynamic features such as ocean eddies, rain clouds, and air masses may split or merge while they are migrating within a space. Topologically, the migration trajectories of such features are structurally more complex as they may have multiple branches due to the splitting and merging processes. Identifying the spatial aggregation pat...

It is a challenge to accurately quantify short-term dynamic human impact on the environment, which is the key to ecosystem and biodiversity conservation. Human's digital footprints are widely used as a proxy of dynamic human impact. This study developed a method to accurately and objectively map the dynamic human's digital footprints in the Tibetan...

Natural disasters cause significant casualties and losses in urban areas every year. Further, the frequency and intensity of natural disasters have increased significantly over the past couple of decades in the context of global climate change. Understanding how urban dwellers learn about and response to a natural hazard is of great significance as...

Understanding city residents' collective geotagged behaviors (CGTBs) in response to hazards and emergency events is important in disaster mitigation and emergency response. It is a challenge, if not impossible, to directly observe CGTBs during a real-time matter. This study used the number of location requests (NLR) data generated by smartphone use...

Dating by the ²³⁰Th method indicates that Stalagmite DANf from Dante Cave in northern Namibia, in the Summer Rainfall Zone (SRZ) of southern Africa, formed about 92 ka, at the boundary of Marine Isotope Stages (MIS) 5b and 5c. In this dominantly semiarid zone, stalagmite growth may be evidence of a relatively wetter period, and trends in DANf's min...

Location-aware big data from social media have been widely used to quantitatively characterize natural disasters and disaster-induced losses. It is not clear how human activities collectively respond to a disaster. In this study, we examined the collective human activities in response to Typhoon Hato at multi spatial scales using aggregated locatio...

Mesoscale eddy process with at least one splitting and/or merging event can be defined as either a complex process or a simple process. Investigation of the difference between these two categories could provide new insights into how different factors, such as the seabed topography, Kuroshio intrusion, and winds, affect the origin, migration, and de...

This study explored city residents’ collective geo-tagged behaviors in response to rainstorms using the number of location request (NLR) data generated by smartphone users. We examined the rainstorms, flooding, NLR anomalies, as well as the associations among them in eight selected cities across the mainland China. The time series NLR clearly refle...

Social and environmental changes had great spatiotemporal variability in the Maya Lowlands during the Classic and Postclassic Periods, and stalagmites promise high-resolution paleoclimate data that can refine our understanding of this complex time. Unfortunately, stalagmites in this region are often difficult to date by U-Th methods because of low...

The daily nighttime lights (NTL) and the amount of location-service requests (NLR) data have been widely used as a proxy for measures of disaster-induced power outages and geo-tagged human activity dynamics. However, the association between the two datasets is not well understood. In this study, we investigated how the NTL signals and geo-tagged hu...

A multi-proxy record of past climate from a stalagmite from Bone Cave in northwestern Botswana suggests relatively wet conditions late in the Little Ice Age and progressively drier conditions in the twentieth century. The proxies include surfaces of dissolution, variation in layer-specific width, changing mineralogy, varying abundance of detrital m...

The climatic event between 4.2 and 3.9 ka BP known as the “4.2 ka event” is commonly considered to be a synchronous global drought that happened as one pulse. However, careful comparison of records from around the world shows that synchrony is possible only if the published chronologies of the various records are shifted to the extent allowed by th...

The Three Rivers Source Region of the Qinghai-Tibet Plateau is a key area that has extensive impacts on much of the population and economy of China as well as several Southeast Asian countries. The rangeland in this area has undergone degradation, the driving factors of which have been extensively investigated in previous studies. However, the effe...

Seventy U-Th ages from six stalagmites from the Cordillera Cantábrica in northwestern Spain indicate deposition during interglacial, but not glacial, stages over the last 550 kyr. Stable isotope data and petrographic observations suggest that, within each interglacial, conditions typically progressed from drier to wetter. Consideration of the most...

Stalagmite Orum-1 from a cave near Orumana in northwestern Namibia provides a multi-proxy record of regional drying with increasing global-scale warmth over the last 47 kyr, in a region with few long well-dated location-specific paleoclimate records. Data from Stalagmite Orum-1 include carbon and oxygen stable isotope ratios, proportions of aragoni...

Multiple proxies using variation in δ¹⁸O, δ¹³C, mineralogy, and petrography in a newly generated high-resolution record of Stalagmite DP1 from Dante Cave indicate a linkage between changes in hydroclimate in northeastern Namibia and changes in solar activity and changes in global temperatures. The record suggests that during solar minima and global...

The stalagmite MC01 was recovered from Macal Chasm cave on the Vaca Plateau of Belize in 1995, and an initial paleoclimate interpretation was published in 2007. Additional uranium-thorium ages have extended the paleoenvironmental record back from 3250 to 5250 cal yr BP, and the stable isotope (δ¹⁸O and δ¹³C) record is dramatically improved by 660 n...

It has become routine to automatically identify mesoscale ocean eddies in the world's oceans and reconstruct their trajectories from remote sensing data. However, the major migration pathways along which eddies mainly propagate are not clear, particularly in the South China Sea (SCS). This study utilized a trajectory partition-and-group method to q...

Horizontal cores from a large stalagmite and two tufa deposits in the entrance to Wonderwerk Cave, South Africa, dated by radiocarbon methods, have provided climate proxy data on late Holocene environments near the cave. The δ18O and δ13C time series from stalagmite Core WW1–3 and tufa Core WW3 correlate well with isotope records for other sites in...

A horizontal core through a large, standing, stalagmite in Carlsbad Caverns National Park, New Mexico, USA, provides a radiometrically dated record of wetter glacial stages and drier interglacial stages over the last 560. kyr. The stalagmite, the Texas Toothpick, is about 7. m tall and about 3. m wide at its base. Two cores through the stalagmite r...

The paper presents a geographical information system (GIS)-based method for depicting the characteristics, particularly the internal structures and evolutionary processes, of mesoscale eddies. This was done by examining topologic relations among closed sea surface height (SSH) contours that were reconstructed from the Naval Research Laboratory Navy...

Very few of current eddy detection algorithms are capable of identifying multieddy structures resulted from interactions among eddies. In this study, we improve our previous hybrid detection (HD) algorithm by incorporating a new criterion to better identify multieddy structures from satellite altimeter data. The criterion defines an aspect ratio to...

A horizontal core through a large, standing, stalagmite in Carlsbad Caverns National Park, New Mexico, USA, provides a radiometrically dated record of wetter glacial stages and drier interglacial stages over the last 560 kyr. The stalagmite, the Texas Toothpick, is about 7 m tall and about 3 m wide at its base. Two cores through the stalagmite reve...

This study presented a quantitative comparison of cockpit and doline karst by examining the numbers and characteristics of typical types of landform entities that are developed in Guilin (Guangxi, China), La Alianza (PR, USA), Avalton (KY, USA), and Oolitic (IN, USA). Five types of landform entities were defined: isolated hill (IH), clustered hills...

This study presents a Gaussian-surface-based approach to identifying multi-eddy structures from the sea level anomaly (SLA) maps. The SLA signals of an eddy are modeled by a two-dimensional anisotropic Gaussian surface. An identification criterion is introduced to determine whether to retain or split a multi-eddy structure. Detection result of a th...

Trajectory data not only contains spatial locations but also rich temporal information. Discovering the temporal characteristics of trajectories is essential for understanding the dynamics of partial moving patterns. This paper presents an analysis approach to exploring temporal features of moving objects. The method first extracted representative...

Automated identification and tracking of mesoscale ocean eddies has recently become one research hotspot in physical oceanography. Several methods have been developed and applied to survey the general kinetic and geometric characteristics of the ocean eddies in the South China Sea (SCS). However, very few studies attempt to examine eddies’ internal...

We compare well-dated Holocene stalagmite δ18O records from the East Asian Summer Monsoon (EASM) region and from the Indian Summer Monsoon (ISM) region. We found that the pattern of latitudinal change of speleothem δ18O values from the Indian monsoon region to the East Asian monsoon region is almost identical to that of modern precipitation. This s...

This research presented a framework to track and query spatiotemporal changes and interactions of dynamic geographic phenomena. The framework organized information of dynamic phenomena as a hierarchy of static structures, processes, and scenarios. Static structures of a dynamic phenomenon at its different evolution stages were described by its core...

Depressions are well developed in certain types of karst landform assemblages. These natural depressions should not be simply filled and removed during the preparation of DEMs. This study presents a research to distinguish karst landform assemblages which tend to have natural depressions from other karst landform assemblages and non-karst landforms...

Ensuring grain security has always been a top priority in China. As one of the major grain production areas in China, southern China is currently being criticized for the urban encroachment on prime agricultural land and decrease in grain production due to Grain-for-Green project. Based on the erosion pattern from the RUSLE model, spatial analysis...

We present a method to integrate case-based reasoning (CBR) with object-oriented image classification to classify SPOT images. Images were first segmented into discrete objects at multiple scales. CBR was then used to classify these objects by comparing their geometric shapes, spectral characteristics, and textural measurements with those of the pa...

Case-based reasoning (CBR) method has been widely used to study environmental and spatial problems since the 1990s. Spatial relations among geographic cases and between case and environment (hereinafter to be referred as spatial relations) were not well considered in most of the previous studies. However, these relations are extremely important in...

China is the most populated country in the world with slightly more than half of the population is still living in rural areas. In the past couple of decades, rapid urbanization and industrialization have significantly changed the land use/land cover (LULC) pattern in rural areas, particularly those around the big cities in eastern China. Shandong...

Urban environment is extremely complex due to a multitude of features with different heights and structures. Traditional methods available to extract information regarding the buildings by using optical remote sensing images are highly labor-intensive and time-consuming. This paper developed a new method to detect building outlines based on height...

A small stalagmite from Cova da Arcoia in the Serra do Courel of northwestern Spain provides a record both of general climate change across the Holocene and of shorter-term shifts between wetter and drier conditions. Nineteen U-series dates from 9.3 ka to the present provide a chronology of the stalagmite with uncertainties of commonly only decades...

Floor Area Ratio (FAR) is an important indicator in urban planning and other urban applications, therefore, it is of great significance to acquire FAR of the functional areas in the city. Traditional method to acquire FAR is slow and of low efficiency. FAR calculation by remote sensing methods can overcome these shortcomings above, so many scholars...