Attribution of Lake Surface Water Temperature Change in Large Lakes Across China Over Past Four Decades

Lake surface water temperature (LSWT) is a key parameter in lake energy budget and is highly vulnerable to climate change. However, the long-term trends in LSWT across China and their driving factors remain uncertain. Here, we used a calibrated lake model to simulate LSWT over 1979-2018 for 91 large lakes (>100 km(2)) across China. Simulations reveal an overall LSWT warming trend (0.040 degrees C yr(-1), p < 0.05), but with large spatial variations. The majority of these lakes show significant warming trends (84%, 0.053 degrees C yr(-1)), while a significant cooling trend is found in the seven lakes in the northwestern Tibetan Plateau (-0.064 degrees C yr(-1)). LSWT of approximately 42% of the lakes increases more rapidly than the corresponding ambient air temperature. Regionally, the warming trend is highest for lakes in the Eastern Plain (0.049 degrees C yr(-1)) and the lowest in the Yunnan-Guizhou Plateau (0.016 degrees C yr(-1)). The increases in simulated LSWT also vary across seasons, with a higher rate in winter and spring than in summer and autumn. Changes in air temperature, downward longwave radiation, and wind speed are the most important climatic drivers for LSWT changes. Lake surface warming could be more rapid under future global warming, necessitating greater attention to lake-atmosphere interactions.