AIR Scientists Propose Novel Method to Estimate Human-caused Heat Emission
Jun 02, 2023
Why cities are usually warmer than rural areas? Scientist have long known that cities retain heat more than rural areas, a phenomenon known as urban heat island (UHI)，largely due to the impact of anthropogenic – or human-caused – heating.
A research team led by Prof. MENG Qingyan from the Aerospace Information Research Institute (AIR), Chinese Academy of Sciences (CAS) proposed an estimation method to quantify the impacts of anthropogenic heat (AH) on UHI. The study was published in Remote Sensing of Environment.
The paper investigates four Chinese megacities including Wuhan, Shanghai, Beijing, and Guangzhou during the periods when COVID-19 pandemic and related control measures severely restricted human activities and notably reduced AH in these cities.
To clarify the effects of COVID-19 control measures on AH, scientists focuses on quantitative assessments by proposing a new AH estimation method based on a remote sensing surface energy balance without hysteresis from heat storage.
According to the study, the reduction was up to 50% in Wuhan during the lockdown in February 2020 and gradually decreased after the lockdown was eased in April 2020, similar to that in Shanghai during the Level 1 pandemic response.
In contrast, AH was less reduced in Guangzhou during the same period and increased in Beijing owing to extended central heating use in winter.
Scientists also found that AH decreased more in urban centers and the change in AH varied in terms of urban land use between cities and periods.
With a much higher spatial resolution, the resulting AH was consistent with the latest global AH dataset, providing “objective and refined features of human activities during the pandemic”, said Prof. Meng.
The paper concluded that, though UHI changes during the COVID-19 pandemic cannot be entirely attributed to AH changes, the considerable reduction in AH is an important feature accompanying the weakening of the UHI.
The study offers insight into the understanding the variation of anthropogenic heat emission in these cities with the context of COVID-19 and provides practical evidence for mitigating urban heat islands and optimizing the urban thermal environment.
Contact: luyq@aircas.ac.cn
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