Tao J H,Fan M,Gu J B and Chen L F. 2020. Satellite observations of the return-to-work over China during the period of COVID-19. Journal of Remote Sensing(Chinese),24(7): 824-836
Tao J H,Fan M,Gu J B and Chen L F. 2020. Satellite observations of the return-to-work over China during the period of COVID-19. Journal of Remote Sensing(Chinese),24(7): 824-836 DOI: 10.11834/jrs.20200098.
Satellite observations of the return-to-work over China during the period of COVID-19
As the coronavirus COVID-19 broke out in the Chinese city of Wuhan and spread across China in late January 2020
governments at all levels in China introduced many policies (e.g. closing factories and schools
staying indoors and clearing street) to limit the further transmission of the illness. Chinese industrial activity was impacted and the return-to-work was delayed by the combination of the Chinese New Year holiday and COVID-19 outbreak. And with the abatement of COVID-19 in China
many provinces have downgraded their emergency response levels. Industrial factories stared to re-open
and people gradually returned to their jobs. In this paper
based on the satellite data
we compared and analyzed the temporal and spatial variations of industrial hot spot and tropospheric NO
2
VCDs before and after the COVID-19 outbreak to estimate the situation of return-to back rate in China.
Generally
several heavy industrial sectors with high-energy consuming (e.g. smelting industries
petrochemical industries and cement industries) have a close relationship with heat-related activities
and the heat emissions can reflect the level of energy consumption to some extent. Therefore
such industrial thermal anomalies have the potential to be detected by satellites sensors with infrared channels. NO
2
primarily comes from fossil fuels burning
such as industrial emissions
power plants and vehicles
and it is a key indicator of industrial activities. NO
2
measured by satellite from high above Earth’s surface are a good indicator of the geographical location of air pollution because NO
2
has a life span of about a day
and thus is concentrated near its sources.
Here
the industrial hot spots and the tropospheric NO
2
Vertical Column Density (VCD) data over China during the periods from January to February in 2020 and 2019
respectively
were used for evaluating the impact of COVID-19 outbreak on China’s return-to-work. The industrial hot spots were extracted from the fires/thermal anomalies results which were retrieved by the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the new generation of polar-orbiting satellite
Suomi National Polar-orbiting Partnership (NPP). The tropospheric NO
2
VCD data were directly obtained from the NO
2
standard product of Ozone Monitoring Instrument (OMI) on Aura satellite.
Our results indicate that there is a significant reduction of levels of energy consumption and NO
2
emissions in February 2020
compared to those of both January 2020 and February 2019. Since the end of the Chinese New Year holiday on February 3
2020
the number
range of distribution and density of industrial hot spots over China has been steadily rising. Except for a small amount of industrial hot spots still being detected in Wuhan
Huangshi and Ezhou
no more industrial hot spot was monitored in other cities of Hubei province in February 2020
meaning that there is no sign of return-to-work in the whole Hubei province. As the coronavirus epidemic eases in China
although the number of industrial hot spots increased remarkably over Jing-Jin-Ji region
the FRPs and tropospheric NO
2
VCDs of most grids with increasing spots were still at low levels
compared to the same period in 2019. It means that production capacities of most heavy industries are limited under the influence of COVID-19 outbreak. Until the early March
both the number and averaged FRP of industrial hot spots began to gradually rise
which reflects the increasing return-to-work rate of heavy industries over most regions of China.
关键词
遥感工业热源能耗水平二氧化氮复工复产疫情期间OMIVIIRS
Keywords
remote sensingindustrial hot spotenergy consumptionNO2return-to-workCOVID-19 outbreakOMIVIIRS
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China Centre for Resources Satellite Data and Application
State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences
Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites, National Satellite Meteorological Center(National Center for Space Weather), China Meteorological Administration
Innovation Center for FengYun Meteorological Satellite (FYSIC), China Meteorological Administration
Center of Emergency Rescue and Safeguard of Heilongjiang Province, Department of Emergency Management of Heilongjiang Province