Evaluation of Present and Future Relationships Between Daily Precipitation and Temperature in Eastern China

ABSTRACT Extreme precipitation is generally expected to intensify in a warmer climate, posing growing risks to ecosystems and human societies. In this study, we aim to examine the precipitation‐temperature relationships in the history and future over eastern China. We first assessed the performance of CMIP6 Multi‐Model Ensemble (MME) and ERA5 reanalysis datasets in simulating mean and extreme precipitation across temperature bins during the historical period (1971–2000) in eastern China. Distinct regional biases are identified: ERA5 overestimates precipitation at moderate temperatures (−10°C to 27°C) and underestimates it at low and high temperatures, while the CMIP6 MME consistently underestimates mean and extreme precipitation across all temperature bins. Both datasets reproduce the observed increasing peak structures, where precipitation intensities increase with temperature up to a peak temperature, and then decline at higher temperatures, closely associated with reduced relative humidity. Observed scaling rates range from 3.90%/°C to 5.89%/°C in northeast China and 3.64%/°C–5.63%/°C in southeast China. ERA5 overestimates these rates, approaching the CC rate (7%/°C), while MME underestimates them, aligning with sub‐CC rates. Scaling rates for extreme precipitation exceed those for mean precipitation, with higher sensitivity for more extreme events. Future projections (2071–2100) under SSP2‐4.5 and SSP5‐8.5 scenarios show similar increasing peak structures, with scaling rates exceeding MME historical values. In northeast China, rates range from 5.12%/°C to 7.03%/°C, significantly higher than northeast China's 2.15%/°C–3.96%/°C. Scaling rates for extreme precipitation are projected to be even higher, indicating increased sensitivity to climate change. These findings underscore the need for improved climate models and reanalysis datasets to capture precipitation dynamics and address rising flood risks in eastern China.