Bin Chen

The University of Hong Kong | HKU · Division of Landscape Architecture

Greenspace plays a crucial role in urban ecosystems and has been recognized as a key factor in promoting sustainable and healthy city development. Recent studies have revealed a growing concern about urban greenspace exposure inequality; however, the extent to which urbanization affects human exposure to greenspace and associated inequalities over...

Here, we combine international air travel passenger data with a standard epidemiological model of the initial 3 mo of the COVID-19 pandemic (January through March 2020; toward the end of which the entire world locked down). Using the information available during this initial phase of the pandemic, our model accurately describes the main features of...

A global consensus has been increasingly acknowledged that the built environment, including man-made or modified structures, surfaces, facilities, and landscapes, influences human health and well-being. Housing price, as a monetary metric to reflect the quality of the built environment regarding properties’ structural and socioeconomic attributes,...

The Olympic Games are one of the most influential mega-events worldwide, yet little is known about the extent how these events transform the physical appearance of urban greenspaces. To fill this knowledge gap, we use time-series satellite images to map annual greenspace distribution across eight host cities of the Summer Olympics between 1988 and...

Green space is an important component in urban environment, providing considerable ecosystem services to our socioeconomic cultural activities. Metrics designed to capture green space provision, supply and demand, measuring availability, accessibility, and visibility have been widely adopted to gauge progress toward achieving sustainable developmen...

Increasing exposure to heat stress threatens the health and well-being of urban residents. However, existing studies on measuring human thermal comfort exposure remain uncertain without considering fine-scale human-heat interaction and its long-term dynamics. To inform this issue, we proposed a population-weighted exposure assessment framework with...

Background: The striking racial disparity in SARS-CoV-2 infection rates in the United States has been frequently reported. It is unclear to what extent the racial disparity in environmental exposure is related to the racial disparity in SARS-CoV-2 infection rates. We adopted 1416 counties in the contiguous United States as research sites to explore...

Accurate and timely mapping of essential urban land use categories (EULUC) is vital to understanding urban land use distribution, pattern, and composition. Recent advances in leveraging big open data and machine learning algorithms have demonstrated the possibility of large-scale mapping of EULUC in a new cost-effective way. However, they are still...

Land surface albedo plays an important role in controlling the surface energy budget and regulating the biophysical processes of natural dynamics and anthropogenic activities. Satellite remote sensing is the only practical approach to estimate surface albedo at regional and global scales. It nevertheless remains challenging for current satellites t...

Timely and accurate population mapping plays an essential role in a wide range of critical applications. Benefiting from the emergence of multi-source geospatial datasets and the development of spatial statistics and machine learning, multi-scale population mapping with high temporal resolutions has been made possible. However, the over-complex mod...

Unprecedented urbanization in China has led to serious urban heat island (UHI) issues, exerting intense heat stress on urban residents. Based on the observed temperature and PM2.5 concentrations in Beijing over 2016–2020, we find diverse influences of aerosol pollution on urban heat island intensity (UHII) under different circulations. When norther...

Intensifying wildfires and human settlement expansion have placed more people and infrastructure at the wildland–urban interface (WUI) areas under risk. Wildfire management and policy response are needed to protect ecosystems and residential communities; however, maps containing spatially explicit information on the distribution of WUI areas are li...

Experiments under controlled conditions have established that ecosystem functioning is generally positively related to levels of biodiversity, but it is unclear how widespread these effects are in real-world settings and whether they can be harnessed for ecosystem restoration. We used a long-term, field-scale tropical restoration experiment to test...

The coronavirus pandemic is an ongoing global crisis that has profoundly harmed public health. Although studies found exposure to green spaces can provide multiple health benefits, the relationship between exposure to green spaces and the SARS-CoV-2 infection rate is unclear. This is a critical knowledge gap for research and practice. In this study...

The United Nations specified the need for “providing universal access to greenspace for urban residents” in the 11th Sustainable Development Goal. Yet, how far we are from this goal remains unclear. Here, we develop a methodology incorporating fine-resolution population and greenspace mappings and use the results for 2020 to elucidate global differ...

The land-sea interface (LSI), generally referred to as coastal areas, is among the most productive ecosystems. In China, the rapid urbanization along the coastal regions has dramatically reshaped the geomorphology, which arouses a series of environmental concerns. Multi-source and multi-scale remote sensing has enabled large-scale monitoring of the...

Greenspace exposure metrics can allow for comparisons of green space supply across time, space, and population groups, and for inferring patterns of variation in opportunities for people to enjoy the health and recreational benefits of nearby green environments. A better understanding of greenspace exposure differences across various spatial scales...

As a key component of wildfire activities, ignition is regulated by complex interactions among climate, fuel, topography, and humans. Considerable studies have advanced our knowledge on patterns and drivers of total area burned and fire frequency, but much is less known about wildfire ignition. To better design effective fire prevention and managem...

Unprecedented urbanization in China has led to serious urban heat island (UHI) issues, exerting intense heat stress on urban residents. Based on observed temperature and PM2.5 concentrations in Beijing over 2016–2020, we find diverse influences of aerosol pollution on urban heat island intensity (UHII) under different circulations. When northerly w...

Plantation is an important land use type that differs from natural forests and affects the economy and the environment. Tree age is one of the key factors used to quantify the impact of plantations. However, there is a lack of datasets explicitly documenting the planting years of global plantations. Here we used time-series Landsat archive from 198...

Urban greenspace, as an essential component of green infrastructure, is particularly important in the urban environment that maintains the function and sustainability of urbanities. With the rapid economic growth over recent decades, China has been experiencing unprecedented urbanisation processes, at the same time, led to dramatic changes in urban...

Burned area has increased across California, especially in the Sierra Nevada range. Recent fires there have had devasting social, economic, and ecosystem impacts. To understand the consequences of new extremes in fire weather, here we quantify the sensitivity of wildfire occurrence and burned area in the Sierra Nevada to daily meteorological variab...

Given the important role of green environments playing in healthy cities, the inequality in urban greenspace exposure has aroused growing attentions. However, few comparative studies are available to quantify this phenomenon for cities with different population sizes across a country, especially for those in the developing world. Besides, commonly...

The cropping intensity has received growing concern in the agriculture field in applications such as harvest area research. Notwithstanding the significant amount of existing literature on local cropping intensities, research considering global datasets appears to be limited in spatial resolution and precision. In this paper, we present an annual d...

Detailed information on urban land uses has been an essential requirement for urban land management and policymaking. Recent advances in remote sensing and machine learning technologies have contributed to the mapping and monitoring of multi-scale urban land uses, yet there lacks a holistic mapping framework that is compatible with different end us...

This study examined the associations between green spaces and one–years' worth of SARS–CoV–2 infection rates across all 3,108 counties in the contiguous United States after controlling for multiple categories of confounding factors. We found green spaces at the county level have a significant negative association with infection rates. Among all typ...

Urban land use information that reflects socioeconomic functions and human activities is critically essential for urban planning, landscape design, environmental management, health promotion, and biodiversity conservation. Land-use maps outlining the distribution, pattern, and composition of essential urban land use categories (EULUC) have facilita...

Urban land-use maps outlining the distribution, pattern, and composition of various land use types are critically important for urban planning, environmental management, disaster control, health protection, and biodiversity conservation. Recent advances in remote sensing and social sensing data and methods have shown great potentials in mapping urb...

Mobility restrictions have been a heated topic during the global pandemic of coronavirus disease 2019 (COVID-19). However, multiple recent findings have verified its importance in blocking virus spread. Evidence on the association between mobility, cases imported from abroad and local medical resource supplies is limited. To reveal the association,...

California’s Sierra Nevada has experienced a large increase in wildfire activities over recent decades. This intensifying fire regime has coincided with a warming climate and increasing human activity, but the relative importance of the biophysical and anthropogenic drivers of wildfire remains unclear across this diverse landscape, especially at a...

Urban land use mapping is critical to understanding human activities in space. The first national mapping result of essential urban land use categories of China (EULUC-China) was released in 2019. However, the overall accuracies in some of the plain cities such as Beijing, Chengdu, and Zhengzhou were lower than 50% because many parcel-based mapping...

Long-term record of fine spatial resolution remote sensing datasets is critical for monitoring and understanding global environmental change, especially with regard to fine scale processes. However, existing freely available global land surface observations are limited by medium to coarse resolutions (e.g., 30 m Landsat) or short time spans (e.g.,...

Context Characterized by intensive urban sprawl and continuous cropland shrinkage, the unprecedented urbanization process has profoundly reshaped China’s landscape over the past four decades. However, the interaction between urban expansion and cropland loss in China at a finer spatiotemporal resolution remains unclear. Objectives This study aims...

Significance By linking seasonality of climate and changing human behavior, we demonstrate that collaboration on global efforts for prompt and intensive intervention is fundamental to coping with future pandemic waves of COVID-19. We propose that this collaboration can be started in locations with typically high population density and international...

Data on the extent, patterns, and trends of human land use are critically important to support global and national priorities for conservation and sustainable development. To inform these issues, we created a series of detailed global datasets for 1990, 2000, 2010, and 2015 to evaluate temporal and spatial trends of land use modification of terrest...

Urban boundaries, an essential property of cities, are widely used in many urban studies. However, extracting urban boundaries from satellite images is still a great challenge, especially at a global scale and a fine resolution. In this study, we developed an automatic delineation framework to generate a multi-temporal dataset of global urban bound...

Satellite-based active fire (AF) products provide opportunities for constructing continuous fire progression maps, a critical data set needed for improved fire behavior modeling and fire management.This study aims to investigate the geospatial interpolation techniques in mapping daily fire progression and assess the accuracy of the derived maps fro...

Since its Reform and Opening-Up, China has been undergoing an unprecedented urbanization process, primarily manifested by intensive urban sprawl and continuous farmland shrinkage. However, few studies have given heed to the interrelation of these two phenomena at a finer spatiotemporal resolution, and limited researches have well quantified what co...

Nighttime light remote sensing has aroused great popularity because of its advantage in estimating socioeconomic indicators and quantifying human activities in response to the changing world. Despite many advances that have been made in method development and implementation of nighttime light remote sensing over the past decades, limited studies ha...

Air pollution over China has attracted wide interest from public and academic community. PM2.5 is the primary air pollutant across China. Quantifying interactions between meteorological conditions and PM2.5 concentrations are essential to understand the variability of PM2.5 and seek methods to control PM2.5. Since 2013, the measurement of PM2.5 has...

A heavy workload is required for sample collection for urban land use classification, and researchers are in urgent need of sampling strategies as a guide to achieve more effective work. In this paper, we make use of an urban land use survey to obtain a complete sample set of a city, test the impact of different training and validation sample sizes...

Lakes play a crucial role in retaining water and altering biogeochemical processes on floodplains. Existing strategies and algorithms for estimation of water storage are insufficient for dynamic floodplain lakes due to the scarcity of available observations. Combining a time series of open water area with a fine spatial-temporal resolution by integ...

The most effective interventions By 23 January 2020, China had imposed a national emergency response to restrict travel and impose social distancing measures on its populace in an attempt to inhibit the transmission of severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2). However, which measures were most effective is uncertain. Tian et al....

Understanding distributions of urban land use is of great importance for urban planning, decision support, and resource allocation. The first mapping results of essential urban land use categories (EULUC) in China for 2018 have been recently released. However, such kind of national maps may not sufficiently meet the growing demand for regional anal...

Satellite-based human settlement extraction methods have limited practical applications, due to merely studying the difference between human settlements with other land cover/use types in physical attributes (e.g., spectral signature and land surface temperature) instead of considering basic anthropogenic attributes (e.g., human distribution and hu...

Undetected cases The virus causing coronavirus disease 2019 (COVID-19) has now become pandemic. How has it managed to spread from China to all around the world within 3 to 4 months? Li et al. used multiple sources to infer the proportion of early infections that went undetected and their contribution to virus spread. The researchers combined data f...

Agricultural productivity is subject to various stressors, including abiotic and biotic threats, many of which are exacerbated by a changing climate, thereby affecting long-term sustainability. The productivity of tree crops such as almond orchards, is particularly complex. To understand and mitigate these threats requires a collection of multi-lay...

Selective logging has been so extensive that harvested forest now exceeds unlogged areas in most tropical forest regions outside of the Amazon. In response, in Southeast Asia, enrichment planting with dipterocarp tree species is carried out in an attempt to accelerate restoration of forest structure and functioning. However, assessing the impacts o...

Data on the extent, patterns, and trends of human land use are critically important to support global and national priorities for conservation and sustainable development. To inform these issues, we created a series of detailed global datasets for 1990, 2000, 2010, and 2015 to evaluate temporal and spatial trends of land use modification of terrest...

Background Estimation of the fraction and contagiousness of undocumented novel coronavirus (COVID-19) infections is critical for understanding the overall prevalence and pandemic potential of this disease. Many mild infections are typically not reported and, depending on their contagiousness, may support stealth transmission and the spread of docum...

Understanding the difference of greenspace in different urban areas is a critical requirement for maintaining urban natural environment and lessening environmental inequality. However, how urban expansion impacts on people's exposure to ambient green environments has been limitedly addressed. Here we integrated multi-source geospatial big data incl...

Respiratory illness caused by a novel coronavirus (COVID-19) appeared in China during December 2019. Attempting to contain infection, China banned travel to and from Wuhan city on 23 January and implemented a national emergency response. Here we evaluate the spread and control of the epidemic based on a unique synthesis of data including case repor...

Land use reflects human activities on land. Urban land use is the highest level human alteration on Earth, and it is rapidly changing due to population increase and urbanization. Urban areas have widespread effects on local hydrology, climate, biodiversity, and food production. However, maps, that contain knowledge on the distribution, pattern and...

Artificial impervious areas are predominant indicators of human settlements. Timely, accurate, and frequent information on artificial impervious areas is critical to understanding the process of urbanization and land use/ cover change, as well as of their impacts on the environment and biodiversity. Despite their importance, there still lack annual...

With the completion of the Beijing Five-year Clean Air Action Plan by the end of 2017, the annual mean PM2.5 concentration in Beijing dropped dramatically to 58.0 µg m−3 in 2017 from 89.5 µg m−3 in 2013. However, controversies exist to argue that favourable meteorological conditions in 2017 were the major driver for such a rapid decrease in PM2.5 c...

In the past few decades, extensive epidemiological studies have focused on exploring the adverse effects of PM2.5 (particulate matters with aerodynamic diameters less than 2.5 μm) on public health. However, most of them failed to consider the dynamic changes of population distribution adequately and were limited by the accuracy of PM2.5 estimations...

Supplementary Materials for Dynamic assessment of PM2.5 exposure and health risk using remote sensing and geo-spatial big data