Spatiotemporal Variations of City-Level Carbon Emissions in China during 2000–2017 Using Nighttime Light Data

China is one of the largest carbon emitting countries in the world. Numerous strategies have been considered by the Chinese government to mitigate carbon emissions in recent years. Accurate and timely estimation of spatiotemporal variations of city-level carbon emissions is of vital importance for planning of low-carbon strategies. For an assessment of the spatiotemporal variations of city-level carbon emissions in China during the periods 2000–2017, we used nighttime light data as a proxy from two sources: Defense Meteorological Satellite Program’s Operational Linescan System (DMSP-OLS) data and the Suomi National Polar-orbiting Partnership satellite’s Visible Infrared Imaging Radiometer Suite (NPP-VIIRS). The results show that cities with low carbon emissions are located in the western and central parts of China. In contrast, cities with high carbon emissions are mainly located in the Beijing-Tianjin-Hebei region (BTH) and Yangtze River Delta (YRD). Half of the cities of China have been making eorts to reduce carbon emissions since 2012, and regional disparities among cities are steadily decreasing. Two clusters of high-emission cities located in the BTH and YRD followed two dierent paths of carbon emissions owing to the diverse political status and pillar industries. We conclude that carbon emissions in China have undergone a transformation to decline, but a very slow balancing between the spatial pattern of high-emission versus low-emission regions in China can be presumed

Nighttime Lights as a Proxy for Economic Performance of Regions

Studying and managing regional economic development in the current globalization era demands prompt, reliable, and comparable estimates for a region’s economic performance. Night-time lights (NTL) emitted from residential areas, entertainment places, industrial facilities, etc., and captured by satellites have become an increasingly recognized proxy for on-ground human activities. Compared to traditional indicators supplied by statistical offices, NTLs may have several advantages. First, NTL data are available all over the world, providing researchers and official bodies with the opportunity to obtain estimates even for regions with extremely poor reporting practices. Second, in contrast to non-standardized traditional reporting procedures, the unified NTL data remove the problem of inter-regional comparability. Finally, NTL data are currently globally available on a daily basis, which makes it possible to obtain these estimates promptly. In this book, we provide the reader with the contributions demonstrating the potential and efficiency of using NTL data as a proxy for the performance of regions

Using Multi-Source Data to Assess the Dynamics of Socioeconomic Development in Africa

Frequent and rapid spatially explicit assessment of socioeconomic development is critical for achieving the Sustainable Development Goals (SDGs) at both national and global levels. In the past decades, scientists have proposed many methods for monitoring human activities on the Earth’s surface on various spatiotemporal scales using Defense Meteorological Satellite Program Operational Line System (DMSP-OLS) nighttime lights (NTL) data. However, the DMSP-OLS NTL data and the associated processing methods have limited their reliability and applicability for systematic measuring and mapping of socioeconomic development. This research utilizes Visible Infrared Imaging Radiometer Suite (VIIRS) NTL and the Isolation Forest (iForest) machine learning algorithm for more intelligent data processing to capture human activities. I use machine learning and NTL data to map gross domestic product (GDP) at 1 km2. I then use these data products to derive inequality indexes like GINI coefficients and 20:20 ratios at nationally aggregate levels. I have also conducted a case study based on agricultural production information to estimate subnational GDP in Uganda. This flexible approach processes the data in an unsupervised manner on various spatial scales. Assessments show that this method produces accurate sub-national GDP data for mapping and monitoring human development uniformly in Uganda and across the globe

Evidence from Satellite Nighttime Lights

학위논문(박사) -- 서울대학교대학원 : 사회과학대학 경제학부, 2021.8. 곽노준.This dissertation investigates the status and the determinants of regional economic performance in North Korea, overcoming data limitations of regional research on the North Korean economy using nighttime light data and geospatial data. The first chapter estimates regional level GDP per capita, assessing the regional economic inequality of North Korea at the county level using nighttime light as a proxy for economic level. The research calculates base gross regional domestic product (GRDP) per capita based on urbanization rates and Bank of Korea’s GDP estimates and derives nighttime light-based GRDP per capita based on the relationship between base GRDP per capita and nighttime light. It also assesses the inequality of North Korean regions at the county level, revealing severe county-level inequality within the province, representing 87% of the total inequality, whereas most previous studies have focused on between-province inequality. In the second chapter, the determinants of regional economic performance in the Kim Jong-un era are analyzed using nighttime light as a proxy for economic performance, revealing that market size and involvement in trade, measured as proximity to trade hubs, contribute to higher nighttime light, while industries do not appear to have a significant effect. Sanctions are shown to significantly reduce nighttime light overall, but the magnitude of the impact is highly divergent across regions. The damage of sanctions is greater in regions with large markets or near trade hubs. In contrast, regions near major wholesale markets appear to better cope with sanctions, although the aggregate effect of sanctions on the region is negative. In the final chapter, the channel of trade effect on regional economies is investigated for the period of recovery from the “Arduous March,” 2001–2016. Three hypotheses of export-led growth, import-led growth, and marketization channel are examined. Historical data from the Japanese colonial era are used as instrumental variables to manage the endogeneity problem of the market. The results indicate that resource export and growth of market in response to trade are the main channels through which sanctions affect regional economies. Conversely, input import does not affect regional economies through any industry. The findings imply that North Korea’s economic recovery from the Arduous March was mainly the result of resource export and market expansion.본 논문은 북한의 시군 단위 지역경제의 현황 및 결정요인을 분석한다. 자료의 부재로 북한의 지역경제 연구는 매우 미흡한 실정이었으나, 기존에 사용되지 않았던 위성 야간조도 및 지리정보라는 새로운 자료를 활용하여 시장, 무역, 산업, 대북경제 제재가 지역경제에 미치는 영향을 실증적으로 분석한다. 첫 번째 연구에서는 김정은 정권 하 북한의 시군 단위 1인당 GRDP를 추정하고 불평등 수준을 평가한다. 북한의 GDP를 도시인구 비중에 비례하여 각 지역별로 배분한 후, 이와 야간조도 간의 관계를 도출하여 1인당 GRDP 를 추정한다. 또한 이를 바탕으로 지니계수 및 일반화된 엔트로피 지수를 도출해 북한의 불평등 추세를 분석하고 불평등 분해를 실시한다. 분석 결과 북한의 1인당 GRDP에는 지역간 상당한 격차가 있었으며, 도 단위에서는 평양대비 56-71%의 수준을 보였다. 그러나 불평등 분해 결과 도 단위의 격차보다 동일 도 내 시·군 간 격차에 따른 불평등이 약 87%를 차지하여 시·군 단위의 지역경제 연구가 매우 중요한 것으로 나타냈다. 두 번째 연구에서는 시장, 무역, 산업을 중심으로 김정은 정권 하 북한 지역 경제 수준의 결정요인과 대북제재가 지역경제에 영향을 분석한다. 이를 위하여 2013-2019년 야간조도 수준을 지역별 경제 수준의 대리변수로 사용하며, 일 부 지역에서 야간조도 값이 관측되지 않는 좌측중도절단(Left censoring) 문제가 발생함에 따라 OLS와 함께 토빗 모형을 사용한다. 분석 결과 시장 규모와 무역 중심지 접근성이 북한 지역경제수준에 긍정적 영향을 미치는 것으로 나타났으며, 산업변수의 영향력은 유의하게 나타나지 않았다. 한편, 대북제재는 북한의 지역 야간조도를 평균적으로 5.4% 감소시키며 특히 시장 활동이 활발하고 무역접근성이 높은 지역에 더 큰 피해를 입히는 것으로 나타났다. 한편, 제재 하에서 도매시장으로의 접근성이 높은 지역은 상대적으로 제재의 효과가 상쇄되는 것으로 나타났는데, 이는 제재 하에서 북한의 국내유통망이 상대적으로 중요해지고 한정된 자원이 도매시장으로 먼저 집중되기 때문인 것으로 해석된다. 세 번째 연구에서는 두 가지 종류의 야간조도 자료를 결합하여 2001-2016년 무역이 지역경제에 영향을 미치는 경로를 분석한다. 북한의 무역 자료는 연간 시계열만 존재하며 북한의 지역단위 변수들은 시간에 대해 불변하므로 무역변수와 지역변수 간의 교차항을 통하여 무역이 어떠한 경제적 특성을 가진 지역에서 더 큰 영향을 미치는지 분석함으로써 수출주도 성장, 수입주도 성장 및 시장화 촉진의 세 가지 가설을 검증한다. 이 때, 시장 변수에 내생성이 존재할 수 있으므로 일제강점기의 지역별 시장 및 기차역 개수를 시장의 도구변수로 사용하여 이를 해결한다. 분석 결과 수입주도 성장은 유효하지 않았으며, 수출의 경우 광업이 발달한 지역에 더 큰 긍정적 영향을 미치는 것으로 나타났다. 또한 수출과 수입 모두 시장의 규모가 큰 지역에 더 큰 긍정적 영향을 미치는 것으로 나타나 무역이 시장의 성장을 촉진하고, 시장이 지역경제를 성장시키는 긍정적 외부효과가 중요한 역할을 한 것으로 나타났다. 수출의 시장을 통한 영향은 시장 정책과 무관하였으나 수입의 경우 친시장 정책이 심화될수록 긍정적 외부효과가 강화되었다. 이상의 결과는 종합적으로 2000년대 이후 및 김정은 정권 하에서 북한 지역경제 성장의 주요 동력은 시장과 무역 및 그 둘 간의 상호작용임을 보여준다. 김정은 정권하는 물론 고난의 행군 이후 북한 경제의 회복기에도 지역별 시장 발전 수준 및 무역 참여도가 지역 경제수준에 큰 영향을 미쳤다. 또한 2017년 이후의 UN 안보리 대북제재가 북한경제에 부정적 영향을 미쳤으며, 특히 북한의 핵심 성장동력인 시장과 무역에 큰 피해를 입히므로 상당한 실효성을 가짐을 시사한다.Introduction 1 Chapter 1. Estimation of North Korean Regional GDP in 2012-2019 Using Nighttime Light Data 5 1. Introduction 5 2. Nighttime Light Data 8 2.1. Introduction 8 2.2. Features of Energy Use in North Korea 10 2.3. Nighttime Light and Welfare Level 13 3. Method and Data 18 3.1. Methodology 18 3.2. Data 21 4. Results 22 4.1. Estimation of GRDP per capita 22 4.2. Regional Disparity of North Korea 29 5. Conclusions 32 Chapter 2. Determinants of the North Korean Regional Economy and the Effect of Sanctions in the Kim Jong-un Era 34 1. Introduction 34 2. Data and Method 37 2.1. Data 37 2.2. Descriptive Statistics 43 2.3. Methodology 47 3. Results 49 3.1. The Determinants of Regional Economic Growth 49 3.2. The Effect of Sanctions 52 3.3. Transmission Channels of the Sanction Effects 54 3.4. Robustness Check 61 4. Conclusions 70 Chapter 3. The effect of trade on the North Korea Economy: Analysis of the Channel 72 1. Introduction 72 2. Method and Data 75 2.1. Hypothesis 75 2.2. Regression model 77 2.3. Data 79 3. Results 86 3.1. Export-Led Growth 86 3.2. Import-Led Growth 89 3.3. Marketization Channel 91 4. Conclusion 99 Concluding Remarks 100 Appendix 102 Reference 107 국문초록 114박

Generating global products of LAI and FPAR from SNPP-VIIRS data: theoretical background and implementation

Leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR) absorbed by vegetation have been successfully generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) data since early 2000. As the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard, the Suomi National Polar-orbiting Partnership (SNPP) has inherited the scientific role of MODIS, and the development of a continuous, consistent, and well-characterized VIIRS LAI/FPAR data set is critical to continue the MODIS time series. In this paper, we build the radiative transfer-based VIIRS-specific lookup tables by achieving minimal difference with the MODIS data set and maximal spatial coverage of retrievals from the main algorithm. The theory of spectral invariants provides the configurable physical parameters, i.e., single scattering albedos (SSAs) that are optimized for VIIRS-specific characteristics. The effort finds a set of smaller red-band SSA and larger near-infraredband SSA for VIIRS compared with the MODIS heritage. The VIIRS LAI/FPAR is evaluated through comparisons with one year of MODIS product in terms of both spatial and temporal patterns. Further validation efforts are still necessary to ensure the product quality. Current results, however, imbue confidence in the VIIRS data set and suggest that the efforts described here meet the goal of achieving the operationally consistent multisensor LAI/FPAR data sets. Moreover, the strategies of parametric adjustment and LAI/FPAR evaluation applied to SNPP-VIIRS can also be employed to the subsequent Joint Polar Satellite System VIIRS or other instruments.Accepted manuscrip

Remote Sensing Evidence for Significant Variations in the Global Gross Domestic Product during the COVID-19 Epidemic

Coronavirus disease 2019 (COVID-19) has been spreading rapidly and is still threatening human health currently. A series of measures for restraining epidemic spreading has been adopted throughout the world, which seriously impacted the gross domestic product (GDP) globally. However, details of the changes in the GDP and its spatial heterogeneity characteristics on a fine scale worldwide during the pandemic are still uncertain. We designed a novel scheme to simulate a 0.1° × 0.1° resolution grid global GDP map during the COVID-19 pandemic. Simulated nighttime-light remotely sensed data (SNTL) was forecasted via a GM(1, 1) model under the assumption that there was no COVID-19 epidemic in 2020. We constructed a geographically weighted regression (GWR) model to determine the quantitative relationship between the variation of nighttime light (ΔNTL) and the variation of GDP (ΔGDP). The scheme can detect and explain the spatial heterogeneity of ΔGDP at the grid scale. It is found that a series of policies played an obvious role in affecting GDP. This work demonstrated that the global GDP, except for in a few countries, represented a remarkably decreasing trend, whereas the ΔGDP exhibited significant differences

Remote sensing of night lights: a review and an outlook for the future

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordRemote sensing of night light emissions in the visible band offers a unique opportunity to directly observe human activity from space. This has allowed a host of applications including mapping urban areas, estimating population and GDP, monitoring disasters and conflicts. More recently, remotely sensed night lights data have found use in understanding the environmental impacts of light emissions (light pollution), including their impacts on human health. In this review, we outline the historical development of night-time optical sensors up to the current state of the art sensors, highlight various applications of night light data, discuss the special challenges associated with remote sensing of night lights with a focus on the limitations of current sensors, and provide an outlook for the future of remote sensing of night lights. While the paper mainly focuses on space borne remote sensing, ground based sensing of night-time brightness for studies on astronomical and ecological light pollution, as well as for calibration and validation of space borne data, are also discussed. Although the development of night light sensors lags behind day-time sensors, we demonstrate that the field is in a stage of rapid development. The worldwide transition to LED lights poses a particular challenge for remote sensing of night lights, and strongly highlights the need for a new generation of space borne night lights instruments. This work shows that future sensors are needed to monitor temporal changes during the night (for example from a geostationary platform or constellation of satellites), and to better understand the angular patterns of light emission (roughly analogous to the BRDF in daylight sensing). Perhaps most importantly, we make the case that higher spatial resolution and multispectral sensors covering the range from blue to NIR are needed to more effectively identify lighting technologies, map urban functions, and monitor energy use.European Union Horizon 2020Helmholtz AssociationNatural Environment Research Council (NERC)Chinese Academy of ScienceLeibniz AssociationIGB Leibniz Institut

Time-based Geospatial Analysis of Night-Time Light Data and Citizen Movement Restriction During Covid-19 Period

Pembatasan kegiatan masyarakat atau di beberapa daerah disebut juga dengan lockdown sudah banyak dijalankan oleh beberapa negara demi menekan angka penyebaran Covid-19. Dalam penelitian ini, menggunakan foto satelit di malam hari, atau biasa disebut dengan Night Time Light (NTL) Data. Setelah itu diambil sample titik koordinat sebanyak 381 tempat umum di Jakarta dan diambil datanya menggunakan dataset VIIRS Stray Light Corrected Nighttime Day/Night Band Composites Version 1 selama kurun waktu Q1 2019 sampai dengan Q2 2022. Dari hasil foto satelit ini kemudian dikonversikan ke dalam bentuk numerik, dikorelasikan dengan timeline pembatasan kegiatan masyarakat di Indonesia dan juga data mobility untuk wilayah Jakarta. Hasilnya adalah ditemukan penurunan intensitas cahaya saat memasuki masa pembatasan kegiatann masyarakat sebanyak 1% - 16% di berbagai sektor. Penurunan intensitas ini tidak berkorelasi dengan kuat dengan data mobility untuk beberapa sektor yang menunjukkan perubahan penurunan aktivitas hingga 60%.Restrictions on community activities or in some areas also called lockdowns have been carried out by many countries in order to reduce the spread of Covid-19. Various methods are used to monitor the implementation of these restrictions, this study uses a new approach by using satellite imagery at night commonly called Night-Time Light (NTL) Data. This research using a sample of 381 coordinate points was taken in public places in Jakarta. The data was collected using the VIIRS Stray Light Corrected Nighttime Day/Night Band Composites Version 1 dataset from Q1 2019 to Q2 2022. The results of these satellite photos were then converted into numerical form and correlated with the timeline for the restriction of community activities in the Jakarta area. The result is there is a slightly decreasing in light intensity when entering a period of Covid-19 at the beginning of 2020 until 2022 with a percentage of around 1% - 16% in various sectors. This decreasing light intensity has a slight correlation with mobility data for several sectors. The mobility data show a huge difference at the beginning of Covid-19, which shows a decrease in the activity of up to 60%

A global North-South division line for portraying urban development

Rapid urbanization has tremendously changed the global landscape with profound impacts on our society. Nighttime light (NTL) data can provide valuable information about human activities and socioeconomic conditions thus has become an effective proxy to measure urban development. By using NTL-derived urban measures from 1992 to 2018, we analyzed the spatiotemporal patterns of global urban development from country to region to city scales, which presented a distinct North-South divergence characterized by the rising and declining patterns. A global North-South division line was identified to partition the globe into the Line-North and the Line-South geographically, which accorded with the socioeconomic difference from the aspects of urban population and economy. This line may keep a certain degree of stability deriving from the trends of population and economic information but also bears uncertainties in the long term