Monitoring Resumption of Work and Production in Wuhan Built-up Area during COVID-19 Based on NPP-VIIRS and Landsat 8 Data

At the beginning of 2020, an outbreak of the Corona Virus Disease 2019 (COVID-19) broke out in Wuhan, Hubei Province, China. With the effective control of the epidemic, all enterprises gradually resumed work and production. The advantage of remote sensing is that it can obtain a large range of data in a short time, which is conducive to the dynamic monitoring of land surface changes. Therefore, using remote sensing technology to monitor the resumption of work and production in Wuhan built-up area is of great significance to economic and social development. This study presented a Vegetation and Building Adjusted NTL Urban Index (VBANUI) based on NPP-VIIRS and Landsat 8 data to extract the built-up of Wuhan. The extraction accuracy of VBANUI was 5.1%, which was better than the traditional method (based on Nighttime Light (NTL): 9.4% and based on Vegetation Adjusted NTL Urban Index (VANUI): 6.5%). The average value of nighttime light intensity and the proportion of high nighttime light intensity in Wuhan built-up areas from April to June were larger than those from January to March in 2020, increasing by 2.8 nW/cm2/sr and 2.6%, respectively. In general, the nighttime light intensity in the built-up area of Wuhan increased gradually with the resumption of work and production. © 2021 IEEE.

An Impact Analysis of Artificial Light at Night (ALAN) on Bats. A Case Study of the Historic Monument and Natura 2000 Wisloujscie Fortress in Gdansk, Poland.

The artificial light at night (ALAN) present in many cities and towns has a negative impact on numerous organisms that live alongside humans, including bats. Therefore, we investigated if the artificial illumination of the historic Wisloujscie Fortress in Gdansk, Poland (part of the Natura 2000 network), during nighttime events, which included an outdoor electronic dance music (EDM) festival, might be responsible for increased light pollution and the decline in recent years of the pond bat (Myotis dasycneme). An assessment of light pollution levels was made using the methods of geographical information system (GIS) and free-of-charge satellite remote sensing (SRS) technology. Moreover, this paper reviewed the most important approaches for environmental protection of bats in the context of ecological light pollution, including International, European, and Polish regulatory frameworks. The analysis of this interdisciplinary study confirmed the complexity of the problem and highlighted, too, the need for better control of artificial illumination in such sensitive areas. It also revealed that SRS was not the best light pollution assessment method for this particular case study due to several reasons listed in this paper. As a result, the authors' proposal for improvements also involved practical recommendations for devising suitable strategies for lighting research and practice in the Natura 2000 Wisloujscie Fortress site located adjacent to urban areas to reduce the potential negative impact of ALAN on bats and their natural habitats.

Quantifying Spatiotemporal Changes in Human Activities Induced by COVID-19 Pandemic Using Daily Nighttime Light Data.

The COVID-19 pandemic caused drastic changes in human activities and nighttime light (NTL) at various scales, providing a unique opportunity for exploring the pattern of the extreme responses of human community. This study used daily NTL data to examine the spatial variations and temporal dynamics of human activities under the influence of COVID-19, taking Chinese mainland as the study area. The results suggest that the change in the intensity of NTL is not correlated to the number of confirmed cases, but reflects the changes in human activities and the intensity of epidemic prevention and control measures within a region. During the outbreak period, the major provincial capitals and urban agglomerations were affected by COVID-19 more than smaller cities. During the recovery, different regions showed different recovery processes. The cities in West and Northeast China recovered steadily while the recovery in coastal cities showed relatively greater fluctuations due to an increase in imported cases. Wuhan, the most seriously affected city in China, did not recover until the end of March. Nevertheless, as of 31 March, the overall NTL across China had recovered to an 89.5% level of the same period in the previous year. The high consistency between the big data of travel intensity and NTL further proved the validity of the results of this study. These findings imply that daily NTL data are effective for rapidly monitoring the dynamic changes in human activities, and can help evaluate the effects of control measures on human activities during major public health events.