Fig. 1: Definition of LCZ and spatiotemporal distribution of LCZ studies.

a The essence of LCZ is a combination of surface structure, cover and human activity. Surface structure describes the height and spacing of buildings and trees, such as the density of buildings (compact, open, sparse, vacant), the height of buildings (high-rise, mid-rise, low-rise), fabric (heavy, lightweight), and the type of vegetation (trees, shrubs, or low-growth), and affects the local climate by altering the balance of air currents, heat transport through the atmosphere, and short-wave and long-wave radiation. Surface cover describes the albedo, moisture supply, and heating/cooling potential of the ground, e.g., vegetative cover, bare soil, bodies of water, paved surfaces, snow, wetlands, etc. Human activity describes the differences in anthropogenic heat emissions, such as those from heavy industry, residential, and commercial. After going through their combinations and eliminating some unlikely classes, 17 standard LCZ classes were identified. b This figure shows the spatial distribution of LCZ research from 2012 to 2023, with LCZ studies being conducted in most regions of the world. Spatially, two hotspot research regions have been formed, namely East Asia and Europe, while fewer studies have been conducted in Latin America, Africa, and Oceania. c This figure shows the trend in the number of papers published in LCZ studies between 2012 and 2023. The number of studies related to the LCZ continues to increase, with the highest number of studies at 91 in 2023.