Ongoing Conflict Makes Yemen Dark: From the Perspective of Nighttime Light

Jian, Wei; He, Guojin; Long, Tengfei; Liu, Huichan

doi:10.3390/rs9080798

Cited by 52 publications

(36 citation statements)

References 46 publications

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“…This includes synthetic aperture radar (SAR) (Braun, Lang, & Hochschild, 2016) and more comprehensive in Braun (2019), or sensors capturing ground-emitted lights at night. Nightlight data have been used as direct indicators for conflicting activities (Witmer & O'Loughlin, 2011) or as indirect cues for ongoing conflicts and crises, as the examples of Syria and Yemen show (Jiang, He, Long, & Liu, 2017).…”

Section: Eo and Gi Technology For (Geo-)humanitarian Actionmentioning

confidence: 99%

Earth observation tools and services to increase the effectiveness of humanitarian assistance

Lang

Füreder

Riedler

et al. 2019

European Journal of Remote Sensing

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Humanitarian action has rapidly adopted Earth observation (EO) and geospatial technologies shaping them according to their needs. Protracted crises and large-scale population displacements require up-to-date information in many facets of humanitarian action support, from mission planning, resource deployment and monitoring, to nutrition and vaccination campaigns, camp plotting, damage assessment, etc. Even though nearly all assets of remote sensing apply in such demanding scenarios, it remains a challenge to fully implement and sustain a trustful and reliable information service. This paper discusses achievements and open issues in the use and uptake of EO technology, from a technical and organisational point of view, motivated by an information service for Médecins Sans Frontières (MSF) and its extension to other NGO's information needs in the humanitarian sector. With a focus on EO-based population estimation based on (semi-)automated dwelling counting from very high-resolution optical satellite imagery as well as the exploitation of data integration (including radar sensors), the paper also covers potential service elements with respect to environmental and ground-or surface water monitoring. It investigates workflow elements in relation to information extraction and delivery by illustrating a broad range of application scenarios, and discusses first operational solutions of a customized service portfolio.

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Section: Eo and Gi Technology For (Geo-)humanitarian Actionmentioning

confidence: 99%

Earth observation tools and services to increase the effectiveness of humanitarian assistance

Lang

Füreder

Riedler

et al. 2019

European Journal of Remote Sensing

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“…where TNL is the total radiance within the study area, L i is the radiance of the i-th pixel, and n t refers to the total number of the pixels in the study area. We did not consider nighttime light pixels with a maximum radiance higher than 3 × 10 −7 W·cm −2 ·sr −1 , most likely gas flares [19]. The main concern was that the fluctuations in the high value of brightness would interfere with the results.…”

Section: Denoising Performancementioning

confidence: 99%

“…It should be noted that the nighttime light radiance of many small settlements might be less than 2 × 10 −9 W·cm −2 ·sr −1 , especially in developing regions; thus, the "threshold" method inevitably filters out useful information on nighttime light related to human settlements. In some studies, nighttime light from biomass burning was removed with the help of masks generated from DMSP-OLS stable images [19,36,37,40]. As mentioned above, DMSP-OLS data are no longer available after 2013.…”

Section: Introductionmentioning

confidence: 99%

Filtering the NPP-VIIRS Nighttime Light Data for Improved Detection of Settlements in Africa

Yuan

Menenti

et al. 2019

Remote Sensing

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Observing and understanding changes in Africa is a hotspot in global ecological environmental research since the early 1970s. As possible causes of environmental degradation, frequent droughts and human activities attracted wide attention. Remote sensing of nighttime light provides an effective way to map human activities and assess their intensity. To identify settlements more effectively, this study focused on nighttime light in the northern Equatorial Africa and Sahel settlements to propose a new method, namely, the patches filtering method (PFM) to identify nighttime lights related to settlements from the National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (NPP-VIIRS) monthly nighttime light data by separating signal components induced by biomass burning, thereby generating a new annual image in 2016. The results show that PFM is useful for improving the quality of NPP-VIIRS monthly nighttime light data. Settlement lights were effectively separated from biomass burning lights, in addition to capturing the seasonality of biomass burning. We show that the new 2016 nighttime light image can very effectively identify even small settlements, notwithstanding their fragmentation and unstable power supply. We compared the image with earlier NPP-VIIRS annual nighttime light data from the National Oceanic and Atmospheric Administration (NOAA) National Center for Environmental Information (NCEI) for 2016 and the Sentinel-2 prototype Land Cover 20 m 2016 map of Africa released by the European Space Agency (ESA-S2-AFRICA-LC20). We found that the new annual nighttime light data performed best among the three datasets in capturing settlements, with a high recognition rate of 61.8%, and absolute superiority for settlements of 2.5 square kilometers or less. This shows that the method separates biomass burning signals very effectively, while retaining the relatively stable, although dim, lights of small settlements. The new 2016 annual image demonstrates good performance in identifying human settlements in sparsely populated areas toward a better understanding of human activities.

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“…In contrast to day-time images, night-time light images provide a special perspective on human activities, because human settlements emit light at night. These satellite-acquired night-time light images have been widely used in socioeconomic studies, including those on power consumption estimation [13], poverty assessment [14,15], urbanization mapping [16][17][18][19][20][21][22][23], regional inequality [24][25][26], Gross Domestic Product (GDP) estimation [27,28], and population movement [29], as well as conflict evaluation in Russia [10], Syria [30,31], Iraq [32], and Yemen [33]. Moreover, night-time light images have also played an important role in mapping light pollution [34][35][36] and evaluating its impact on human health [37,38].…”

Section: Introductionmentioning

confidence: 99%

Night-Time Light Dynamics during the Iraqi Civil War

Liu

Jendryke

et al. 2018

Remote Sensing

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In this study, we analyzed the night-time light dynamics in Iraq over the period 2012-2017 by using Visible Infrared Imaging Radiometer Suite (VIIRS) monthly composites. The data quality of VIIRS images was improved by repairing the missing data, and the Night-time Light Ratio Indices (NLRIs), derived from urban extent map and night-time light images, were calculated for different provinces and cities. We found that when the Islamic State of Iraq and Syria (ISIS) attacked or occupied a region, the region lost its light rapidly, with the provinces of Al-Anbar, At-Ta'min, Ninawa, and Sala Ad-din losing 63%, 73%, 88%, and 56%, of their night-time light, respectively, between December 2013 and December 2014. Moreover, the light returned after the Iraqi Security Forces (ISF) recaptured the region. In addition, we also found that the night-time light in the Kurdish Autonomous Region showed a steady decline after 2014, with the Arbil, Dihok, and As-Sulaymaniyah provinces losing 47%, 18%, and 31% of their night-time light between December 2013 and December 2016 as a result of the economic crisis in the region. The night-time light in Southern Iraq, the region controlled by Iraqi central government, has grown continuously; for example, the night-time light in Al Basrah increased by 75% between December 2013 and December 2017. Regions formerly controlled by ISIS experienced a return of night-time light during 2017 as the ISF retook almost all this territory in 2017. This indicates that as reconstruction began, electricity was re-supplied in these regions. Our analysis shows the night-time light in Iraq is directly linked to the socioeconomic dynamics of Iraq, and demonstrates that the VIIRS monthly night-time light images are an effective data source for tracking humanitarian disasters in that country.

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Ongoing Conflict Makes Yemen Dark: From the Perspective of Nighttime Light

Abstract: Abstract:The Yemen conflict has caused a severe humanitarian crisis. This study aims to evaluate the Yemen crisis by making use of time series nighttime light images

Cited by 52 publications

References 46 publications

Earth observation tools and services to increase the effectiveness of humanitarian assistance

Earth observation tools and services to increase the effectiveness of humanitarian assistance

Filtering the NPP-VIIRS Nighttime Light Data for Improved Detection of Settlements in Africa

Night-Time Light Dynamics during the Iraqi Civil War

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