Reduction in human activity can enhance the urban heat island: insights from the COVID-19 lockdown

Chakraborty, TC; Sarangi, Chandan; Lee, Xuhui

doi:10.1088/1748-9326/abef8e

Cited by 56 publications

(49 citation statements)

References 61 publications

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“…Daytime LST decreased by −1.96 K in rural areas and by −1.76 K in urban areas. ( Chakraborty et al, 2021 ) Major cities of India Satellite-derived NO 2 and AOD were dropped by 18

43% and 4

34%. Both day and night time LST exhibited a negative anomaly by 1°C and 2.1°C, respectively.…”

Section: Discussionmentioning

confidence: 99%

Impact of COVID-19 induced lockdown on land surface temperature, aerosol, and urban heat in Europe and North America

Parida

Bar

Kaskaoutis

et al. 2021

Sustainable Cities and Society

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The outbreak of SARS CoV-2 (COVID-19) has posed a serious threat to human beings, society, and economic activities all over the world. Worldwide rigorous containment measures for limiting the spread of the virus have several beneficial environmental implications due to decreased anthropogenic emissions and air pollutants, which provide a unique opportunity to understand and quantify the human impact on atmospheric environment. In the present study, the associated changes in Land Surface Temperature (LST), aerosol, and atmospheric water vapor content were investigated over highly COVID-19 impacted areas, namely, Europe and North America. The key findings revealed a large-scale negative standardized LST anomaly during nighttime across Europe (–0.11°C to –2.6°C), USA (–0.70°C) and Canada (–0.27°C) in March–May of the pandemic year 2020 compared to the mean of 2015–2019, which can be partly ascribed to the lockdown effect. The reduced LST was corroborated with the negative anomaly of air temperature measured at meteorological stations (i.e. –0.46°C to –0.96°C). A larger decrease in nighttime LST was also seen in urban areas (by ∼1–2°C) compared to rural landscapes, which suggests a weakness of the urban heat island effect during the lockdown period due to large decrease in absorbing aerosols and air pollutants. On the contrary, daytime LST increased over most parts of Europe due to less attenuation of solar radiation by atmospheric aerosols. Synoptic meteorological variability and several surface-related factors may mask these changes and significantly affect the variations in LST, aerosols and water vapour content. The changes in LST may be a temporary phenomenon during the lockdown but provides an excellent opportunity to investigate the effects of various forcing controlling factors in urban microclimate and a strong evidence base for potential environmental benefits through urban planning and policy implementation.

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“…Daytime LST decreased by −1.96 K in rural areas and by −1.76 K in urban areas. ( Chakraborty et al, 2021 ) Major cities of India Satellite-derived NO 2 and AOD were dropped by 18

43% and 4

34%. Both day and night time LST exhibited a negative anomaly by 1°C and 2.1°C, respectively.…”

Section: Discussionmentioning

confidence: 99%

Impact of COVID-19 induced lockdown on land surface temperature, aerosol, and urban heat in Europe and North America

Parida

Bar

Kaskaoutis

et al. 2021

Sustainable Cities and Society

View full text Add to dashboard Cite

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“…The model simulated UHI values at surface (UHI surface ) are first evaluated against satellite-derived estimates of mean summer (JJA) UHI surface from MODIS overpasses (4 times a day). To calculate UHI surface from MODIS, the mean Land Surface Temperature (LST) over the city is subtracted from the mean LST of a normalized buffered region (which is approximately equal to the area of the city) around the city (see Chakraborty et al, 2021). For consistency, corresponding UHI surface values are calculated using the same methodology for the WRF CNTL run and averaged over the 6-year simulation period.…”

Section: Model Evaluation At City Scalementioning

confidence: 99%

Urbanization Amplifies Nighttime Heat Stress on Warmer Days Over the US

Sarangi

Qian

et al. 2021

Geophysical Research Letters

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Urbanization is the most tangible local-scale impact of humans on the Earth's surface and the surface climate (Jia et al., 2020;Kalnay & Cai, 2003). Urbanization-associated perturbations in land use/land cover (LULC) can substantially alter the micro-climate of cities via re-adjustment of the surface energy balance. Specifically, urban regions are observed to be warmer (based on temperature measured at 2 meter) and drier (based on moisture mixing ratio at 2 meter) than peripheral rural areas, commonly referred in the literature as Urban Heat Island (UHI) (e.g., Oke and Cleugh., 1991) and Urban Dry Island (UQI) (Oke & Cleugh, 1987), respectively. Along with LULC changes, urbanization is also associated with increases in the heat generated by anthropogenic activities or anthropogenic heat flux (AHF) into the urban atmosphere. Notably, the global urban population has crossed ∼4 billion (half of the total global population) and is expected to reach up to ∼7 billion, accounting for two-third of the total global population, by 2050 (Ritchie & Max, 2018). The human body's ability to dissipate metabolic heat through evaporative cooling (sweating) and heat conduction is inversely proportional to the ambient temperature and humidity (Sherwood & Huber, 2010). Consequently, urbanization-induced perturbations in micro-climate can substantially affect a large portion of the global population in the near future via urban-induced heat stress intensity (UHSI) and its associated economic impacts (

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“…The realism of the IBPM framework has been extensively documented in the past, for example, in studies of temperature perturbation due to urbanization (Zhao et al, 2014), deforestation (Bright et al, 2017;Burokowski et al, 2018), and agricultural activities (Chakraborty et al, 2021;Ruehr et al, 2020), and in a study of lake surface temperature change (S. Wang et al, 2018;W. Wang et al, 2018).…”

Section: Attributing Surface Temperature Perturbations Through Radiative and Non-radiative Pathwaysmentioning

confidence: 99%

Strong Local Evaporative Cooling Over Land Due to Atmospheric Aerosols

Chakraborty

Lee

Lawrence

2021

J Adv Model Earth Syst

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Aerosols modify the Earth's radiative budget through scattering and absorption of solar (shortwave) and terrestrial (longwave) radiation and have large variability in their physical and chemical properties, horizontal and vertical distributions, and feedbacks from other components of the climate system, particularly clouds (Persad & Caldeira, 2018;Ramanathan, 2001). Overall, aerosol climatic effects lead to one of the largest uncertainties in future climate projections (Hinds, 1999;Stocker, 2014). Unlike the effect of well-mixed greenhouse gases, the aerosol radiative effect is stronger at the surface than at the top of the atmosphere (Ramanathan, 2001), with aerosols reducing incoming shortwave radiation through scattering and absorption and increasing incoming longwave radiation through re-emission of the absorbed energy (Chakraborty

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Reduction in human activity can enhance the urban heat island: insights from the COVID-19 lockdown

Cited by 56 publications

References 61 publications

Impact of COVID-19 induced lockdown on land surface temperature, aerosol, and urban heat in Europe and North America

Impact of COVID-19 induced lockdown on land surface temperature, aerosol, and urban heat in Europe and North America

Urbanization Amplifies Nighttime Heat Stress on Warmer Days Over the US

Strong Local Evaporative Cooling Over Land Due to Atmospheric Aerosols

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