Thermal environment characteristics of local climate zones during winter cold waves in severe cold regions

With the acceleration of global climate change and urbanization, extreme weather events in cities have become increasingly frequent, severely impacting urban living environments. However, most existing studies focus on heat waves (HW), while research on cold waves (CW) in severe cold regions during winter is insufficient. This study employed the local climate zones (LCZ) method and conducted long-term fixed-point measurements of near-surface air temperature (Ta) and relative humidity (RH) in eight LCZs in Shenyang during the winter. It examined differences in air temperature, humidity, urban heat island (UHI), wind speed, and direction across LCZs during CW, normal days (ND), and cooling days (CD) in severe cold regions. Results showed that, compared to ND, the extreme low temperatures and low wind speeds during CW caused a sharp drop in temperature across all LCZs, thereby increasing the temperature differences between LCZs. Relative humidity increased while absolute humidity (AH) decreased. UHI weakened slightly during CD but was significantly enhanced during CW. Urban heat island intensity (UHII) in high-density LCZs (2, 4, 5) increased the most, rising by 0.2–2.5°C during the day and 1–6°C at night. This study provides empirical evidence and scientific support for climate adaptation planning in severe cold regions.