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

Exploration of eco-environment and urbanization changes in coastal zones: A case study in China over the past 20 years

Abstract With the rapid development of urbanization and population migration, since the 20th century, the natural and eco-environment of coastal areas have been under tremendous pressure due to the strong interference of human response. To objectively evaluate the coastal eco-environment condition and explore the impact from the urbanization process, this paper, by integrating daytime remote sensing and nighttime remote sensing, carried out a quantitative assessment of the coastal zone of China in 2000–2019 based on Remote Sensing Ecological Index (RSEI) and Comprehensive Nighttime Light Index (CNLI) respectively. The results showed that: 1) the overall eco-environmental conditions in China's coastal zone have shown a trend of improvement, but regional differences still exist; 2) during the study period, the urbanization process of cities continued to advance, especially in seaside cities and prefecture-level cities in Jiangsu and Shandong, which were much higher than the average growth rate; 3) the Coupling Coordination Degree (CCD) between the urbanization and eco-environment in coastal cities is constantly increasing, but the main contribution of environmental improvement comes from non-urbanized areas, and the eco-environment pressure in urbanized areas is still not optimistic. As a large-scale, long-term series of eco-environment and urbanization process change analysis, this study can provide theoretical support for mesoscale development planning, eco-environment condition monitoring and environmental protection policies from decision-makers

Mapping of nighttime light trends and refugee population changes in Ukraine during the Russian–Ukrainian War

The nighttime lights accurately and coherently depict how humans live. This study uses nighttime light measurements to quantify changes in nighttime lighting and refugee population in Ukraine before and after the war. We combined the Theil–Sen estimator with the M-K test to explore the trends of nighttime light. In addition, we constructed a linear model using nighttime light data and a portion of the UNHCR refugee data. Our results reveal that 1 week after the start of the Russo-Ukrainian War, the nighttime light area and the average nighttime light DN value in Ukraine exhibited a steep decline of about 50 percent. Our findings showed taht refugee population changes calculated through models and nighttime light data were mostly consistent with UNHCR data. We thought that the nighttime light data might be used directly to dynamically estimate changes in the refugee movement throughout the war. Nighttime light changes has significant implications for international humanitarian assistance and post-war reconstruction

Multisource Remote Sensing based Impervious Surface Mapping

Impervious surface (IS) not only serves as a key indicator of urbanization, but also affects the micro-ecosystem. Therefore, it is essential to monitor IS distribution timely and accurately. Remote sensing is an effective approach as it can provide straightforward and consistent information over large area with low cost. This thesis integrates multi-source remote sensing data to interpretate urban patterns and provide more reliable IS mapping results. Registration of optical daytime and nighttime lights (NTL) data is developed in the first contribution. An impervious surface based optical-to-NTL image registration algorithm with iterative blooming effect reduction (IS_iBER) algorithm is proposed. This coarse-to-fine procedure investigates the correlation between optical and NTL features. The iterative registration and blooming effect reduction method obtains precise matching results and reduce the spatial extension of NTL. Considering the spatial transitional nature of urban-rural fringes (URF) areas, the second study proposed approach for URF delineation, namely optical and nighttime lights (NTL) data based multi-scale URF (msON_URF).The landscape heterogeneity and development vitality derived from optical and NTL features are analyzed at a series of scales to illustrate the urban-URF-rural pattern. Results illustrate that msON_URF is effective and practical for not only concentric, but also polycentric urban patterns. The third study proposes a nighttime light adjusted impervious surface index (NAISI) to detect IS area. Parallel to baseline subtraction approaches, NAISI takes advantage of features, rather than spectral band information to map IS. NAISI makes the most of independence between NTL-ISS and pervious surface to address the high spectral similarity between IS and bare soil in optical image. An optical and NTL based spectral mixture analysis (ON_SMA) is proposed to achieve sub-pixel IS mapping result in the fourth study. It integrates characteristics of optical and NTL imagery to adaptively select local endmembers. Results illustrate the proposed method yields effective improvement and highlight the potential of NTL data in IS mapping. In the fifth study, GA-SVM IS mapping algorithm is investigated with introduction of the achieved urban-URF-rural spatial structure. The combination of optical, NTL and SAR imagery is discussed. GA is implemented for feature selection and parameter optimization in each urban scenario

EU cohesion policy on the ground: Analyzing small-scale effects using satellite data

We present a novel approach to analyze the effects of EU cohesion policy on local economic activity. For all municipalities in the border area of the Czech Republic, Germany, and Poland, we collect project-level data on EU funding in the period between 2007 and 2013. Using night light emission data as a proxy for economic development, we show that receiving a higher amount of EU funding is associated with increased economic activity at the municipal level. Our paper demonstrates that remote sensing data can provide an effective way to model local economic development also in Europe, where comprehensive cross-border data are not available at such a spatially granular level

Remote Sensing of Natural Hazards

Each year, natural hazards such as earthquakes, cyclones, flooding, landslides, wildfires, avalanches, volcanic eruption, extreme temperatures, storm surges, drought, etc., result in widespread loss of life, livelihood, and critical infrastructure globally. With the unprecedented growth of the human population, largescale development activities, and changes to the natural environment, the frequency and intensity of extreme natural events and consequent impacts are expected to increase in the future.Technological interventions provide essential provisions for the prevention and mitigation of natural hazards. The data obtained through remote sensing systems with varied spatial, spectral, and temporal resolutions particularly provide prospects for furthering knowledge on spatiotemporal patterns and forecasting of natural hazards. The collection of data using earth observation systems has been valuable for alleviating the adverse effects of natural hazards, especially with their near real-time capabilities for tracking extreme natural events. Remote sensing systems from different platforms also serve as an important decision-support tool for devising response strategies, coordinating rescue operations, and making damage and loss estimations.With these in mind, this book seeks original contributions to the advanced applications of remote sensing and geographic information systems (GIS) techniques in understanding various dimensions of natural hazards through new theory, data products, and robust approaches

Book of short Abstracts of the 11th International Symposium on Digital Earth

The Booklet is a collection of accepted short abstracts of the ISDE11 Symposium

Essays on Energy and Development in sub-Saharan Africa: Energy access, climate change, and the Nexus

La seguente Tesi di Dottorato si articola in cinque saggi che esaminano alcuni importanti aspetti legati all'energia in Africa subsahariana, e in particolare all'interazione tra lo sviluppo socio-economico e le sue implicazioni per l'ambiente a livello regionale e globale. I saggi sono introdotti da un capitolo di avvicinamento generale ai temi trattati. Questo capitolo prepara il lettore offrendo un riassunto delle principali sfide legate all'energia nel contesto subsariano e formulando le domande di ricerca e gli strumenti sui quali si basa la tesi stessa. Le principali implicazioni di ciascuno dei saggi, sia per la ricerca che per i decisori politici, vengono poi presentate in un capitolo di discussione finale. Il primo saggio esamina la problematica dell’accesso all'energia, e in particolare all'elettricità. Viene illustrato il ruolo dei dati satellitari e dell'analisi statistica dei dati geospaziali nel migliorare la comprensione della situazione dell'accesso all'elettricità in Africa subsahariana. Il saggio include un'analisi delle disuguaglianze che caratterizzano la qualità dell'accesso all'elettricità nella regione. Il risultato principale è che, dopo decenni, la disuguaglianza nell'accesso all'energia sta iniziando a diminuire. Essa rimane però prominente, in particolare per quanto riguarda la quantità di energia consumata. Viene stimato che gli sforzi di elettrificazione tra il 2020 e il 2030 debbano triplicare il loro passo per raggiungere l'obiettivo di sviluppo sostenibile SDG 7.1.1. Il secondo saggio consiste di una piattaforma di valutazione della domanda energetica bottom-up spazialmente esplicita per stimare il fabbisogno energetico tra le comunità in cui l'accesso all'elettricità è attualmente carente, come identificato con la metodologia introdotta nel primo saggio. La valutazione non si limita al fabbisogno energetico residenziale, ma include un resoconto dettagliato, basato sugli usi finali, del fabbisogno energetico di scuole, strutture sanitarie, pompaggio dell'acqua per l'irrigazione, lavorazione delle colture e microimprese, i principali motori dello sviluppo rurale. Viene condotto uno studio nazionale per il Kenya per dimostrare l'importanza di considerare molteplici fonti di domanda oltre al residenziale quando l'obiettivo è sviluppare una strategia di elettrificazione che supperisca veramente alla povertà energetica. Si dimostra poi che esiste un notevole potenziale di crescita della produttività e della redditività rurale grazie all'apporto di energia elettrica. In molte aree, questi profitti locali potrebbero ripagare gli investimenti nelle infrastrutture di elettrificazione in pochi anni. Il terzo saggio analizza un aspetto specifico dell'interazione tra pianificazione dell'accesso all'elettricità, domanda di energia residenziale e adattamento ai cambiamenti climatici. Vengono combinati dati e scenari climatici, satellitari e demografici per produrre una stima globale spazialmente esplicita della domanda di circolazione e condizionamento dell’aria non soddisfatta a causa della mancanza di accesso all'elettricità. Sulla base di modelli integrati di elettrificazione climatica-energetica e geospaziale, risulta che in Africa sub-sahariana, l'hotspot globale della povertà energetica, tenere conto del fabbisogno di circolazione e condizionamento dell’aria locale stimato (in aggiunta agli obiettivi di consumo residenziale di base) determini una riduzione sostanziale della quota di sistemi standalone come l'opzione di elettrificazione meno costosa entro il 2030, e un importante aumento della capacità di generazione di elettricità e dei requisiti di investimento. Tali risultati suggeriscono la necessità di una maggiore considerazione delle esigenze di adattamento climatico nella pianificazione dei sistemi energetici dei paesi in via di sviluppo e nella valutazione del trade-off tra l'espansione della rete elettrica centrale e sistemi decentralizzati per raggiungere un’elettrificazione universale. La pianificazione dell'elettrificazione deve essere tecnicamente efficiente, ma deve anche considerare l'ambiente politico-economico in cui gli investimenti vengono canalizzati. Il quarto saggio valuta il ruolo della governance e della qualità regolatoria nel quadro di modellazione dell'accesso all'energia elettrica. In particolare, si introduce un indice di governance dell'accesso all'elettricità basato su più indicatori che viene poi implementato nel modello di elettrificazione IMAGE-TIMER. L’effetto dell’indice viene modellato attraverso il suo effetto modificatore sui tassi di sconto privati (una misura del rischio e della disponibilità ad accettare costi futuri rispetto ai costi attuali). I risultati mostrano che la governance e la qualità regolatoria nell'accesso all'elettricità hanno un impatto significativo sul mix tecnologico ottimale e sui flussi di investimenti privati per raggiungere l'elettrificazione universale in Africa subsahariana. In particolare, un ambiente rischioso scoraggia l’investimento da parte dei fornitori privati di soluzioni di accesso decentralizzato all'energia, con il rischio di lasciare molti senza elettricità anche oltre il 2030. Il quinto e ultimo saggio analizza il settore energetico africano da un punto di vista ‘Nexus’. Il saggio valuta l'affidabilità del sistema energetico nei sistemi energetici dominati dall'energia idroelettrica (come in molti paesi dell'Africa centrale e orientale) e del ruolo che i cambiamenti climatici e gli eventi estremi possono esercitare su di esso. Il lavoro combina analisi qualitative e quantitative per (i) proporre un solido framework per evidenziare le interdipendenze tra energia idroelettrica, disponibilità di acqua e cambiamento climatico, (ii) analizzare sistematicamente lo stato dell'arte sugli impatti previsti dei cambiamenti climatici su l'energia idroelettrica nell'Africa subsahariana e (iii) fornire evidenza empirica sui trend passati e sulle traiettorie di sviluppo futuro del settore. I risultati suggeriscono che il cambiamento climatico influenzerà l'affidabilità e la sicurezza della fornitura elettrica attraverso diversi canali. Ad esempio, molti dei principali bacini idrologici sono stati caratterizzati da una diminuzione del livello idrico nel corso del ventesimo secolo. Si evidenzia come tuttavia una diversificazione del mix di generazione elettrico sia finora stata promossa solo in un numero limitato di paesi. Si suggerisce infine che l'integrazione delle fonti rinnovabili variabili con l'energia idroelettrica possa aumentare la resilienza del sistema.This dissertation is a collection of five essays examining some important energy-related aspects at the interplay of sub-Saharan Africa (SSA)’s development and its interactions with the regional and global environment. The essays are introduced by a general overview chapter – highlighting the core energy-related challenges of SSA and the scope of this work. The main implications of the essays, both for research and for policymakers, are then considered in the final discussion chapter. The first essay focuses on access to modern energy, and chiefly on electricity. I illustrate the role of satellite data and the statistical analysis of geospatial data in improving the understanding of the electricity access situation in sub-Saharan Africa. The essay includes an analysis of inequality characterising the electricity access quality in the region. The main finding is that after decades, energy access inequality is beginning to decline but it remains prominent in particular as far as the quantity consumed is concerned. I find that electrification efforts between 2020 and 2030 must triplicate their pace to meet Sustainable Development Goal 7.1.1. The second essay develops a spatially-explicit bottom-up energy demand assessment platform to estimate the energy needs among communities where access to electricity is currently lacking, as identified with the methodology introduced in the first essay. The assessment is not restricted to residential energy needs, but it includes a detailed, appliance-based account of power needs for schools, healthcare facilities, water pumping for irrigation, crop processing, and micro enterprises, the key drivers of rural development. I carry out a country-study for Kenya to show the importance of considering multiple demand sources beyond residential when the aim is developing an electrification strategy which truly overcomes energy poverty. I also show that there is considerable potential for rural productivity and profitability growth thanks to the input of electric energy. In many areas, these local profits might pay back the electrification infrastructure investment in only few years. The third essay analyses a specific aspect at the interplay between electricity access planning, household energy demand and climate change adaptation. I combine climate, satellite, and demographic data and scenarios to produce a global spatially-explicit estimate of unmet ACC demand due to the lack of electricity access. Based on integrated climate-energy and geospatial electrification modelling, I find that in sub-Saharan Africa, the global hotspot of energy poverty, accounting for the estimated local ACC needs on top of baseline residential consumption targets determines a substantial reduction in the share of decentralised systems as the least-cost electrification option by 2030, and a major ramp-up in the power generation capacity and investment requirements. My results call for a greater consideration of climate adaptation needs in the planning of energy systems of developing countries and in evaluating the trade-off between the central power grid expansion and decentralised systems to achieve universal electrification. Electrification planning must be techno-economically efficient, but it must also consider the political-economic environment where investment needs to be channelled. The fourth essay evaluates the role of governance and regulatory quality in the electricity access modelling framework. In particular, I introduce an Electricity Access Governance Index based on multiple indicators implement it into the PBL’s IMAGE-TIMER electrification model through its modifier effect on private discount rates (a measure of risk and willingness to accept future costs vis-à-vis present costs). The results show that governance and regulatory quality in electricity access have a significant impact on the optimal technological mix and the private investment flows for reaching universal electrification in sub-Saharan Africa. In particular, risky environment crowd out private providers of decentralised energy access solutions with the risk of leaving many without electricity even after 2030. The fifth and final essay takes a nexus perspective in the analysis of the African power sector. It deals with the reliability of the energy system in hydropower-dominated power systems (such as in many countries in Central and East Africa) and the role that climate change and extreme events can exert on it. The essay combines qualitative and quantitative analysis to (i) propose a robust framework to highlight the interdependencies between hydropower, water availability, and climate change, (ii) systematically review the state-of-the art literature on the projected impacts of climate change on hydropower in sub-Saharan Africa, and (iii) provide supporting evidence on past trends and current pathways of power mix diversification, drought incidence, and climate change projections. I find that climate change can affect supply reliability and security in multiple ways. For instance, several major river basins have been drying throughout the twentieth century. Nonetheless, I highlight that diversification has hitherto only been promoted in a limited number of countries. I suggest how integrating variable renewables and hydropower can increase system resilience

CIRA annual report FY 2014/2015

Reporting period July 1, 2014-March 31, 2015