Nighttime Light Intensity Research Articles

Correlation Analysis Between Nighttime Light Data and Socioeconomic Factors on Fine Scales

Nighttime light (NTL) radiance can reflect human settlements and activities. A lot of studies indicate that NTL brightness can be a sound proxy of socioeconomic factors on large scales, such as the population size, gross domestic product, electric power consumption, etc. However, few studies have been dedicated to these topics on fine scales. In this study, we examined the correlation between the Suomi National Polar-orbiting Partnership-Visible Infrared Imaging Radiometer Suite (S-NPP/VIIRS) NTL intensity (NLI) and population density, as well that between NLI and per capita income at two census units’ levels, census tract and block group, in two research areas. The result shows that the NLI has a moderate or weak positive correlation with the population density at both scales. However, when land use type is integrated with population density, the correlation becomes very strong. The NLI and per capita income have a weak or very weak negative correlation at both scales. Moreover, we find that the correlation coefficient is positively correlated with the unit’s size. The larger scale also has a higher correlation coefficient. The research conducted here could be beneficial for the application of S-NPP/VIIRS NTL data in studying socioeconomic activities in human settlement areas.

Intercalibration of Luojia1-01 and Suomi-NPP-VIIRS Monthly Nighttime Light Composite Using a Spatial-Temporal Residuals Correction Random Forest Model

Satellite-derived Nighttime light (NTL) data from the Suomi National Polar-orbiting Partnership (Suomi-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) and Luojia1-01 (LJ1-01) have been widely used in multiple urban aspects. However, the inconsistency in NTL intensity (the same spatial coverage and month) between the two sensors impedes their integration on finer scales. To alleviate this issue, a novel model was developed to simulate LJ1-01-like NTL in March 2019, considering Guangzhou main city (GZMC) as the study area, Shenzhen, Dongguan, and Huizhou as validation cities to confirm the spatial simulation ability of the model. First, the spatial features originated from VIIRS NTL and geographical data to enhance the prior spatial information for NTL. Second, the temporal features were derived from the VIIRS NTL time series between 2018 and 2020, such as inter-annual and intra-annual trends, to describe the temporal fluctuation of NTL. Third, a spatial-temporal residuals correction random forest (STRCRF) regression model was proposed to generate LJ1-01-like NTL validation with 10-fold cross-validation (CV). It established the nonlinear relationship between LJ1-01 NTL intensity and spatial-temporal features at the pixel level. It generated LJ1-01-like NTL data with a CV-R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 0.982 and a CV-RMSE of 3469. The validation accuracy with R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ranged from 0.918 to 0.945, and RMSE varied from 4139 to 7298 in Shenzhen, Dongguan, and Huizhou. The evaluations of LJ1-01-like NTL based on the statistic analyses, spatial patterns, and profile analyses indicated the effectiveness of the STRCRF model in improving NTL intensity consistency at the pixel and landscape level. Moreover, the STRCRF model outperformed the previous related studies and improved the CV-R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> by 0.4. Our approach offers the potential for simulating LJ1-01-like NTL by taking advantage of the prior spatial and temporal information and the ensemble regression with residuals correction. This method could contribute to a higher quality NTL dataset for mapping human activities and monitoring the urban environment.

The potential of nighttime light remote sensing data to evaluate the development of digital economy: A case study of China at the city level

As one of the new and crucial fields of economic development, the digital economy refers to the economic activities associated with digital technologies and information. The traditional measurement mainly relies on the statistical data, which are regionally specific and labour cost. As an appropriate proxy for socio-economic activities, nighttime light (NTL) remote sensing data was used in this study to explore its potential in estimating the digital economy. Then, the Zipf's law was used to evaluate the growth of the digital economy at the city level. The results show that the total NTL intensity has a logarithmic relationship with the digital economy index and can be estimated for each cities' digital economy growth in China from 2017 to 2020 (R2 ≈ 0.7). An unbalanced distribution and a decentralized polycentric structure of digital economy are found among all cities in China. But the top 100 cities have a relative harmonious development with a better goodness of Zipf's law. Finally, four main incentives behind the digital economy growth were concluded for three stages of the digital economy growth. This study could enrich the understanding of digital economy and have valuable implications for its future growth in China.

Urban vertical profiles of three most urbanized Chinese cities and the spatial coupling with horizontal urban expansion

Earth has entered the century of city. Horizontal urban expansion has long been studied and is relatively well understood, but the knowledge of the vertical profiles of built structures remains limited. Here we propose a spatially explicit ensemble model and map the wall-to-wall building height of the three most urbanized Chinese cities in 2017 based on open-access Sentinel-1 SAR data, biophysical indices derived from Sentinel-2 multispectral imageries, and nighttime light (NTL) intensity. We further conduct a chronosequence analysis of the building height for these cities along with their horizontal urban expansion between 1985 and 2017. We show that our proposed method performs well in generating 1 km × 1 km building height maps in Beijing (R2 = 0.87, RMSE = 3.53 m), Shanghai (R2 = 0.82, RMSE = 4.21 m), and Shenzhen (R2 = 0.78, RMSE = 6.92 m). Shenzhen has the tallest (mean building height (MBH) = 37.63 m) and most diverse (coefficient of variation (CV) = 63.84%) vertical landscapes, followed by Shanghai (MBH = 29.86 m, CV= 51.14%). And the vertical profile is the lowest (MBH = 19.21 m) and relatively homogeneous (CV = 44.93%) in Beijing. We also find that vertical urban profiles are coupled with horizontal urban expansion, evidenced by an increase in building height along with the decreasing proximity to urban centers and the increasing urbanization intensity, and a clear imprint of urbanization age in all three cities. The specific characteristics vary among cities due primarily to local urbanization strategies. The knowledge of the vertical profiles of the three most urbanized Chinese cities complements the horizontal insights into urbanization and can assist sustainable land use and urban planning.

Political instability and households’ investment behavior: Evidence from Burkina Faso

There is a large, rather macroeconomic, literature that shows that political instability and social conflict are associated with poor economic outcomes including lower investment and reduced economic growth. However, there is only very little research on the impact of instability on households’ behavior, in particular their saving and investment decisions. We merge six rounds of household survey data and a geo-referenced time series of politically motivated events and fatalities from the Armed Conflict Location and Event Data Base (ACLED) to analyze households’ decisions when exposed to instability in Burkina Faso. For identification, we exploit variation in the intensity of political instability across time and space while controlling for time- and municipality-fixed effects as well as rainfall and nighttime light intensity, and many other potential confounders. Our results show a negative association of political instability and financial savings, the accumulation of durables, investment in house improvements, as well as investment in education and health. Instability seems, in particular, to lead to a reshuffling from investment expenditures to increased food consumption, implying lower growth prospects in the future. With respect to economic growth, the sizable education and health effects seem to be particularly worrisome.

Investigating the spatially heterogeneous impacts of urbanization on city-level industrial SO2 emissions: Evidence from night-time light data in China

The spatial distribution and the identification of the influential factors of industrial sulfur dioxide (SO2) emissions have received extensive attention. However, evidence is still lacking on the spatial impacts of urbanization on industrial SO2 emissions at the city scale in China. This work builds a Geography Weighted Regression (GWR) model on a Stochastic Impacts by Regression on Population, Affluence and Technology (STIRPAT) framework to investigate the spatially heterogeneous impacts of potential influencing factors on city-level industrial SO2 emissions from 288 prefecture-level cities in China. The results show that the GWR model significantly improved the goodness-of-fit of the model. The influence of night-time light intensity of the cities, as a proxy of the urbanization level, was calculated to be median (min, max): −0.505(-0.918, −0.413). The highest impacts of urbanization were observed in the Northeast and Southwest regions. Industrial influencing factors had generally promoted the growth of SO2 emissions, with higher positive impacts in western cities. We concluded that urbanization had a significant and negative effect on industrial SO2 emissions in most Chinese cities. It is necessary to formulate emission reduction and city development policies simultaneously based on the trade-offs between urbanization and air pollution control targets.

Analyzing Pixel-Level Relationships between Luojia 1-01 Nighttime Light and Urban Surface Features by Separating the Pixel Blooming Effect

Nighttime light (NTL) remote sensing data can effectively reveal human activities in urban development. It has received extensive attention in recent years, owing to its advantages in monitoring urban socio-economic activities. Due to the coarse spatial resolution and blooming effect, few studies can explain the factors influencing NTL variations at a fine scale. This study explores the relationships between Luojia 1-01 NTL intensity and urban surface features at the pixel level. The Spatial Durbin model is used to measure the contributions of different urban surface features (represented by Points-of-interest (POIs), roads, water body and vegetation) to NTL intensity. The contributions of different urban surface features to NTL intensity and the Pixel Blooming Effect (PIBE) are effectively separated by direct effect and indirect effect (pseudo-R2 = 0.915; Pearson correlation = 0.774; Moran’s I = 0.014). The results show that the contributions of different urban surface features to NTL intensity and PIBE are significantly different. Roads and transportation facilities are major contributors to NTL intensity and PIBE. The contribution of commercial area is much lower than that of roads in terms of PIBE. The inhibitory effect of water body is weaker than that of vegetation in terms of NTL intensity and PIBE. For each urban surface feature, the direct contribution to NTL intensity is far less than the indirect contribution (PIBE of total neighbors), but greater than the marginal indirect effect (PIBE of each neighbor). The method proposed in this study is expected to provide a reference for explaining the composition and blooming effect of NTL, as well as the application of NTL data in the urban interior.

Using Daily Nighttime Lights to Monitor Spatiotemporal Patterns of Human Lifestyle under COVID-19: The Case of Saudi Arabia

A novel coronavirus, COVID-19, appeared at the beginning of 2020 and within a few months spread worldwide. The COVID-19 pandemic had some of its greatest impacts on social, economic and religious activities. This study focused on the application of daily nighttime light (NTL) data (VNP46A2) to measure the spatiotemporal impact of the COVID-19 pandemic on the human lifestyle in Saudi Arabia at the national, province and governorate levels as well as on selected cities and sites. The results show that NTL brightness was reduced in all the pandemic periods in 2020 compared with a pre-pandemic period in 2019, and this was consistent with the socioeconomic results. An early pandemic period showed the greatest effects on the human lifestyle due to the closure of mosques and the implementation of a curfew. A slight improvement in the NTL intensity was observed in later pandemic periods, which represented Ramadan and Eid Alfiter days when Muslims usually increase the light of their houses. Closures of the two holy mosques in Makkah and Madinah affected the human lifestyle in these holy cities as well as that of Umrah pilgrims inside Saudi Arabia and abroad. The findings of this study confirm that the social and cultural context of each country must be taken into account when interpreting COVID-19 impacts, and that analysis of difference in nighttime lights is sensitive to these factors. In Saudi Arabia, the origin of Islam and one of the main sources of global energy, the preventive measures taken not only affected Saudi society; impacts spread further and reached the entire Islamic society and other societies, too.

Detection of Artisanal and Small-Scale Gold Mining Activities and Their Transformation Using Earth Observation, Nighttime Light, and Precipitation Data.

The rapid growth of artificially constructed mining camps has negatively impacted the camps’ surrounding environment and the informal communities that have developed inside the camps. However, artisanal and small-scale gold mining (ASGM) is generally informal, illegal, and unregulated; thus, transformations of the mining activities and potential social-environmental problems resulting from these changes are not revealed. This study assesses the transformation of mining activities in camp-type ASGM sectors in Gorontalo, Indonesia, during 2014–2020 using remotely sensed data, such as Landsat series, nighttime light, and precipitation data obtained through Google Earth Engine. Results show that the combined growth of the built-up areas increased 4.8-fold, and their annual mean nighttime light increased 3.8-fold during 2014–2019. Furthermore, diverse increases in the sizes of area and nighttime light intensity were identified from the mining camps. Among the studied camps, since 2017, Motomboto camp 3 showed a particularly rapid change in activity regardless of the season of the year. Hence, these approaches are capable of identifying rapid transformations in the mining activities and provide significant insight into the socio-environmental problems originating from the closed and vulnerable camp-based ASGM sector. Our results also contribute to developing rapid and appropriate interventions and strengthening environmental governance.

Estimating economic activity of South African provinces using satellite technology: An econometric panel data application

This article studies the economic application of the remote sensing of night-time light emissions using satellite technologies within the South African context, focusing on its nine provinces as the unit of investigation. Observing human activity from outer space using satellite technology and remote sensing focusing on man-made light emissions presents real opportunity, especially where reliable national statistics are lacking. The methodology involves the estimation of panel data, autoregressive distributed lag and co-integration models that estimate provincial night-time light intensity as a proxy for provincial gross regional product (GDP). Both the ARDL and co-integrating models point to a long-run co-integrating relationship between GDP and night-time total light intensity, while the panel models suggest that the inverse Henderson elasticity for all provinces is 0.277 (cross-section fixed model). The ARDL models also establish a statistically significant short-term error correction term. The combined results suggest that a statistically significant long- and short-term relationship does indeed exist between provincial GDP and night-time lights within the South African and provincial context.

Monitoring the Spatiotemporal Trajectory of Urban Area Hotspots Using the SVM Regression Method Based on NPP-VIIRS Imagery

Urban area hotspots are considered to be an ideal proxy for spatial heterogeneity of human activity, which is vulnerable to urban expansion. Nighttime light (NTL) images have been extensively employed in monitoring current urbanization dynamics. However, the existing studies related to NTL images mainly concern detection of urban areas, leaving inner spatial differences in urban NTL luminosity poorly explored. In this study, we propose an innovative approach to explore the spatiotemporal trajectory of urban area hotspots using monthly Visible Infrared Imaging Radiometer Suite (VIIRS) NTL images. Firstly, multi-temporal VIIRS NTL intensity was decomposed by time-series analysis to obtain annual stable components after data preprocessing. Secondly, the support vector machine (SVM) regression model was utilized to identify urban area hotspots. In order to ensure the model accuracy, the grid search and cross-validation method was integrated to achieve the optimized model parameters. Finally, we analyzed the spatiotemporal migration trajectory of urban area hotspots by the center of gravity method (i.e., shift distance and angle of urban area hotspot centroid). The results indicate that our method successfully captured urban area hotspots with a regression coefficient over 0.8. Meanwhile, the findings give an intuitive understanding of coupling interaction between urban area hotspots and socioeconomic indicators. This study provides important insights for further decision-making regarding sustainable urban planning.

Spatial-Temporal Changes and Associated Determinants of Global Heating Degree Days.

The heating degree days (HDDs) could indicate the climate impact on energy consumption and thermal environment conditions effectively during the winter season. Nevertheless, studies on the spatial-temporal changes in global HDDs and their determinants are scarce. This study used multi-source data and several methods to explore the rules of the spatial distribution of global HDDs and their interannual changes over the past 49 years and some critical determinants. The results show that global HDDs generally became larger in regions with higher latitudes and altitudes. Most global change rates of HDDs were negative (p < 0.10) and decreased to a greater extent in areas with higher latitudes. Most global HDDs showed sustainability trends in the future. Both the HDDs and their change rates were significantly partially correlated with latitude, altitude, mean albedo, and EVI during winter, annual mean PM2.5 concentration, and nighttime light intensity (p = 0.000). The HDDs and their change rates could be simulated well by the machine learning method. Their RMSEs were 564.08 °C * days and 3.59 °C * days * year−1, respectively. Our findings could support the scientific response to climate warming, the construction of living environments, sustainable development, etc.

Characterizing the river water quality in China: Recent progress and on-going challenges

Food production systems, urbanization, and other anthropogenic activities dramatically alter natural hydrological and nutrient cycles, and are primarily responsible for water quality impairments in China's rivers. This study compiled a 16-year (2003–2018) dataset of river water quality (161,337 records from 2424 sites), watershed/landscape features, and meteorological conditions to investigate the spatial water quality patterns and underlying drivers of river impairment (defined as water quality worse than Class V according to China's Environmental Quality Standards for Surface Waters, GB3838-2002) at a national scale. Our analysis provided evidence of a distinct water quality improvement with a gradual decrease in the frequency of prevalence of anoxic conditions, an alleviation of the severity of heavy metal pollution, whereas the cultural eutrophication has only been moderately mitigated between 2003 and 2018. We also identified significant spatial variation with relatively poorer water quality in eastern China, where 17.2% of the sampling sites registered poor water quality conditions, compared with only 4.6% in western China. Total phosphorus (TP) and ammonia-nitrogen (NH3-N) are collectively responsible for >85% of the identified incidences of impaired conditions. Bayesian modelling was used to delineate the most significant covariates of TP/NH3-N riverine levels in six large river basins (Liao, Hai, Yellow, Yangtze, Huai, and Pearl). Water quality impairments are predominantly shaped by anthropogenic drivers (82.5% for TP, 79.5% for NH3-N), whereas natural factors appear to play a secondary role (20.5% for TP, 17.5% for NH3-N). Two indicator variables of urbanization (urban areal extent and nighttime light intensity) and farmland areal extent were the strongest predictors of riverine TP/NH3-N levels and collectively accounted for most of the ambient nutrient variability. We concluded that there is still a long way to go in order to eradicate eutrophication and realize acceptable ecological conditions. The design of the remedial measures must be tailored to the site-specific landscape characteristics, meteorological conditions, and should also consider the increasing importance of non-point source pollution and internal nutrient loading.

Increasing duration and intensity of nighttime supplemental lighting promotes growth and photosynthesis in young Cymbidium plants

This study was conducted to determine how nighttime supplemental lighting (NSL) duration and light intensity influence the growth and photosynthesis of young Cymbidium plants. Seven-month-old Cymbidium ‘Yang Guifei’ and ‘Wine Shower’ plants were grown under five NSL durations (2, 4, 6, 8, and 16 h) and three NSL light intensities (10, 100, and 200 µmol·m−2·s−1) for 4 months, which provided 16 NSL light integrals ranging from 0 to 11.52 mol·m−2·d−1 including 0 h NSL treatment. The NSL treatments were provided by 100% red LEDs, and CO2 was supplied during the nighttime (16 h) at 800 µmol·mol−1. Pseudobulb diameter, the number of leaves, and biomass accumulation significantly increased with increasing NSL duration and light intensity in both cultivars. These growth characteristics showed increasing trends with increasing NSL light integrals. In particular, pseudobulb diameter increased by 33 and 43% in ‘Yang Guifei’ and ‘Wine Shower,’ respectively, as the NSL light integral increased from 0 to 11.52 mol·m−2·d−1. Relative chlorophyll contents decreased with increasing NSL light intensity in ‘Yang Guifei’. Photosynthetic assimilation rate (An) during NSL was promoted in response to increases of NSL duration and light intensity in both cultivars, implying that the An increased with increasing NSL light integrals. However, in this study, continuous lighting (16 h NSL) limited daytime photosynthesis. Daily An showed a positive correlation with pseudobulb diameter. These results indicated that NSL could accelerate the growth of young Cymbidium plants by inducing nighttime photosynthesis. In this study, considering that continuous NSL could inhibit the daytime photosynthesis, the 8 h NSL with 200 µmol·m−2·s−1 treatment was the most effective for promoting the growth. This finding can be used to maximize the growth rate and shorten the cultivation time in Cymbidium production.

Evaluation of Light Pollution in Global Protected Areas from 1992 to 2018

Light pollution, a phenomenon in which artificial nighttime light (NTL) changes the form of brightness and darkness in natural areas such as protected areas (PAs), has become a global concern due to its threat to global biodiversity. With ongoing global urbanization and climate change, the light pollution status in global PAs deserves attention for mitigation and adaptation. In this study, we developed a framework to evaluate the light pollution status in global PAs, using the global NTL time series data. First, we classified global PAs (30,624) into three pollution categories: non-polluted (5974), continuously polluted (8141), and discontinuously polluted (16,509), according to the time of occurrence of lit pixels in/around PAs from 1992 to 2018. Then, we explored the NTL intensity (e.g., digital numbers) and its trend in those polluted PAs and identified those hotspots of PAs at the global scale with consideration of global urbanization. Our study shows that global light pollution is mainly distributed within the range of 30°N and 60°N, including Europe, north America, and East Asia. Although the temporal trend of NTL intensity in global PAs is increasing, Japan and the United States of America (USA) have opposite trends due to the implementation of well-planned ecological conservation policies and declining population growth. For most polluted PAs, the lit pixels are close to their boundaries (i.e., less than 10 km), and the NTL in/around these lit areas has become stronger over the past decades. The identified hotspots of PAs (e.g., Europe, the USA, and East Asia) help support decisions on global biodiversity conservation, particularly with global urbanization and climate change.

Agriculture-Nutrition Linkages, Cooking-Time, Intrahousehold Equality Among Women and Children: Evidence from Tajikistan

Household-level agriculture-nutrition linkage (ANL) tends to be strong where food markets are imperfect. In such an environment, markets for cooking services may also be imperfect. Nutrition outcomes of household members, including intrahousehold inequality among women and children can depend on a household’s self-production of food and cooking services, provided both by household labors, particularly of women. Using the primary data in Tajikistan, we show that longer cooking-time by women in the household often strengthens household-level ANL and also reduces intrahousehold inequality in nutritional outcomes among women and children. These effects are stronger in areas with lower nighttime light intensity and for households with lower values of cooking assets. In a context where household-level ANL is strong, ANL may also depend on households’ self-production of complementary inputs, including cooking services. This dependence reveals both unique opportunities for and vulnerabilities of ANL for the rural poor.

Lights along the frontier: convergence of economic activity in the proximity of the Polish-German border, 1992–2012

ABSTRACT This paper studies regional economic development on the municipality-level in Poland and Germany along the Oder–Neisse border. We use high-quality satellite night-time light intensity data as an innovative and comparable measure to proxy for overall economic activity on both sides of the border consistently over a long period of time (1992–2012). We use descriptive heat maps as well as regression analysis to investigate two aspects: first, how far is the economic convergence along the Polish-German border? Second, what effect does the distance to the border have on economic activity as measured with light emissions? Our findings suggest that convergence in overall activity across the border has been complete. Polish municipalities that used to be economically much weaker have caught up with those on the German side of the Oder and the Neisse rivers. As regards the importance of distance, we highlight different results for Germany and Poland. While distance to the border never mattered significantly for German regions, Polish municipalities closer to the border used to be substantially worse off in the early 1990s but caught up with regions further to the east by the end of the period of our analysis.

Impact of a sleep promotion protocol on off-pump coronary artery bypass graft patients.

Sleep abnormalities frequently occur in intensive care unit (ICU) patients, and the consequences of sleep abnormalities in patients who undergo off-pump coronary artery bypass graft (OPCABG) surgery are particularly significant. Although many interventions have been reported to improve sleep, few sleep promotion protocols have been designed specifically for patients in cardiac ICUs. This study aimed to explore the effects of an evidence-based sleep promotion protocol on patients who underwent OPCABG in a cardiac ICU. A quasi-experimental study was conducted in a comprehensive hospital in Shandong province of China. Overall, 67 participants were recruited (37 in the control group and 30 in the intervention group). An evidence-based sleep promotion protocol was developed by a 10-member interprofessional collaborative team and then applied. Sound levels, light intensity, and the number of nocturnal interventions were compared between groups. The Chinese version of the Richards-Campbell Sleep Questionnaire (RCSQ) was used to compare intergroup sleep status on two consecutive postoperative nights. No significant differences were found for demographics or disease severity between the groups. In the intervention group, sound levels and light intensity were significantly lower at various times, and nocturnal interventions were significantly less frequent over the two consecutive nights. RCSQ scores were significantly higher in the intervention group for both nights. The sleep promotion protocol reduced sound levels, night-time light intensity, the number of nocturnal interventions, and improved sleep among OPCABG patients in a cardiac ICU. Evidence-based practice can help to promote good quality of care, improve patient outcomes, and advance nursing in clinical settings.

Ethnic Diversity and Local Economies

AbstractThe effect on economic outcomes of ethnic diversity remains debatable. Some view ethnic diversity as a deterrent of development, whereas others consider it a source of innovation and productivity, which can be translated into a higher level of development. This study aims to shed further light on the issue. Applying instrumental variables estimation to district‐level data, we find that ethnic diversity has a significant positive association with nighttime light intensity, which is used as a proxy for level of economic activity. The finding is robust to alternative specifications. Our finding suggests that centuries of interethnic contacts and coexistence may have helped ethnically diverse communities to gain experimental knowledge of the diverse beliefs and social practices and transition it into better economic outcomes.

Linking ecological background and demand to identify ecological security patterns across the Guangdong-Hong Kong-Macao Greater Bay Area in China

Ecological security pattern (ESP) can maintain regional ecological security and thus support sustainable development. ESP should not only protect regional ecological processes, but also meet human demand for ecosystem services. It is aimed to propose a new method of identifying ecological sources in consideration of ecological background and demand, with a case study across the Guangdong-Hong Kong-Macao Greater Bay Area in view of interregional ecological conservation cooperation. Ecological sources were identified with high supply and high comprehensively ecological supply–demand ratio (CESDR) of ecosystem services. Land use based resistance surface was modified using nighttime light intensity. Ecological corridors and potential ecological corridors were extracted using the Minimum Cumulative Resistance model. Ecological sources were mainly distributed in the north, accounting for 13.46% of the total area. Macao and Dongguan had no ecological sources, due to the high level of land urbanization, and the mismatch between high supply and high CESDR patches, respectively. Ecological sources in Hong Kong were connected with that in Shenzhen, showing good background of natural ecosystem connectivity as the foundation for interregional ecological conservation cooperation. Ecological corridors were mainly distributed in the periphery of the study area, connecting most cities except for Macao. The overall ESP showed a spatially circular pattern around the Greater Bay Area. The new method for ecological source identification could effectively enhance the sustainability of ecosystem conservation in view of integrating supply and demand of ecosystem services. It was necessary for all the three regions to strengthen ecological conservation cooperation.