Identifying the dominant impact factors and their contributions to heatwave events over mainland China

Spatiotemporal variation in heatwaves and elderly population exposure across China

Heatwaves have been intensified worldwide due to climate change, posing great health risks, especially to elderly populations. However, in China, limited studies have employed the heat index to decipher the spatiotemporal trends of heatwaves and their impacts on the elderly population. By comparing the three heatwave definitions, this study aimed to evaluate the long-term spatiotemporal variations in heatwaves from 1964 to 2022 across China using the Excess Heat Factor (EHF). We took advantage of high-resolution reanalysis temperature data on the Google Earth Engine (GEE) platform to efficiently calculate the heatwaves. Our results revealed that the frequency and duration of heatwaves increased significantly in approximately 77 % of China's total area, with South China experiencing the most frequent and prolonged heatwaves. Conversely, in most areas, no significant trend was discerned in the growth of the maximum and average heatwave intensities. The total number of elderly people affected by heatwaves surged from approximately 11.96 million in 2001 to over 30.31 million in 2020, with an estimated additional 1.12 million older adults exposed to heatwaves annually across the nation (R2 = 0.60, p < 0.05). The population factor exhibited largest effect on the exposure of heatwaves, followed by climate effects and combined factors, with the corresponding explanatory power about 42.84 %, 34.85 % and 22.31 %, respectively. These individuals predominantly resided in the Northeast China, Southwest China, and South China. We also found geographical variations in heatwave exposure along elevations and land use types. These insights underscore the pressing necessity for formulating strategic interventions to mitigate the health threats presented by mounting heatwave exposure, especially for susceptible groups like the elderly in China.

Preparation of a Novel Structure-Designed Porous Ceramsite for Water Retention

Ceramsites can be used as water storage materials, but the challenges of low water absorption and short water-retention time are restricted to their application. In this paper, a novel multilayer powder coatings method was used to prepare a structure-designed ceramsite. The results showed that the structure-designed ceramsite can be prepared by a multilayer powder coating method. A ceramsite with large internal and small external pores has superior properties, with a water absorption rate of 51.3% at 24 h and a water-retention time of 56 h at 50 °C and 55% RH. This work not only broadens the new way of solid waste resource utilization but also has great significance in promoting the construction of sponge cities and overcoming the urban heat island effect.