Detectable Anthropogenic Influences on Icing Days and Their Intensity Over China During 1961–2020 and Associated Observationally Constrained Projection

Abstract Icing days refer to the days with daily maximum temperature below 0°C, and they can cause adverse impacts on the agricultural production, infrastructure, and communication facilities. Given the limitation in quantifying human influence on icing days in China, we investigate the spatiotemporal variations in icing days and associated intensity over China during 1961–2020, and conduct detection and attribution analyses by using the optimal fingerprinting method, based on the observations from the gridded data set CN05.1 and simulations from 25 Coupled Model Intercomparison Project Phase 6 (CMIP6) models. Remarkably downward trends in icing days and upward trends in their intensity are found over China during 1961–2020 from both observations and simulations. The anthropogenic (ANT) signal is clearly detected in the observed changes over China and its eastern (east of 105°E) and western (west of 105°E) regions. The greenhouse gases (GHG) play a dominant role, while the attributable changes from natural (NAT) and anthropogenic aerosol (AER) signals are generally negligible. After the attribution‐constraints, the annual icing days are projected to decrease by 14.5 days and strengthen by 0.9°C over China in the long‐term period (2081−2100) relative to 1995−2014 under the Shared Socioeconomic Pathway SSP2‐4.5 scenario, and those values are 26.1 days and 1.5°C under the SSP5‐8.5 scenario, respectively. In the future projections, the uncertainty range of observation‐constrained projections is narrowed over China and its eastern and western regions in the 21st century under SSP2‐4.5 and SSP5‐8.5 scenarios. This paper provides assistance for better dealing with climate change.