Lake-effect snowfall(LES)occurs when cold air moves across open lakes.LES is expected to occur more frequently over the TP,due to the intensified lake expansion caused by intensified global warming.Thus,there is an ur...Lake-effect snowfall(LES)occurs when cold air moves across open lakes.LES is expected to occur more frequently over the TP,due to the intensified lake expansion caused by intensified global warming.Thus,there is an urgent need to comprehensively assess the LES over the TP.Here,we revealed that the LES is triggered by westerly southward shift leading to the drop in air temperature and is positively correlated with lake area,wind speed and longitude across 12 large lakes(>300 km^(2))based on satellite observations and reanalysis data.Using a sensitivity model simulation,we determined that large lakes in the southern TP contributed to more than 50%of the snowfall in the downwind area in 2013.Projections indicate that the westerly-triggered LES will increase under the future RCP4.5 climate warming scenario,highlighting the importance of developing adaptive policies to address the growing risks associated with future LES.展开更多
In this study, high-resolution weather research and forecasting(WRF) simulations are used to explore the sensitivity of lake-effect convection over Poyang Lake(PL) to the change of lake surface temperature(LST). A con...In this study, high-resolution weather research and forecasting(WRF) simulations are used to explore the sensitivity of lake-effect convection over Poyang Lake(PL) to the change of lake surface temperature(LST). A control experiment(CTR) with climate mean LST(303 K) is compared with six sensitivity experiments(CTR-1/2/3K and CTR+1/2/3K) in which the LSTs are set based on the mean LST difference of 6 K between the maximum and minimum. The results show that the CTR experiment reasonably reproduces the lake-effect convection, and the lake-effect convection in sensitivity experiments is significantly influenced by the LST. With the increase of LST, the initiation time of the lake-effect convection is advanced gradually, while the initiation location moves PL from its shore.The lake-effect convection strengthens(weakens) in the increase-temperature CTR+1/2/3K(decrease-temperature CTR-1/2/3K) experiments, but the lake-effect convection does not monotonically strengthen with the LST, for the strongest one occurring in the CTR+1K experiment. The corresponding diagnostic analysis shows that the upward sensible heat flux and latent heat flux over PL increase with the LST, resulting in the enhancement of the lake-land breeze and the enlargement of the convective available potential energy(CAPE). This is the main reason for the changes in the initiation time and location, as well as the intensity of lake-effect convection in different experiments.In addition, the non-monotonous variation of the level of free convection, which is mainly induced by the non-monotonous variation of the lifting condensation level, is responsible for the non-monotonous variation of the lake-effect convection intensity with the LST.展开更多
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences(CAS2022067)the Basic Science Center for Tibetan Plateau Earth System(41988101)。
文摘Lake-effect snowfall(LES)occurs when cold air moves across open lakes.LES is expected to occur more frequently over the TP,due to the intensified lake expansion caused by intensified global warming.Thus,there is an urgent need to comprehensively assess the LES over the TP.Here,we revealed that the LES is triggered by westerly southward shift leading to the drop in air temperature and is positively correlated with lake area,wind speed and longitude across 12 large lakes(>300 km^(2))based on satellite observations and reanalysis data.Using a sensitivity model simulation,we determined that large lakes in the southern TP contributed to more than 50%of the snowfall in the downwind area in 2013.Projections indicate that the westerly-triggered LES will increase under the future RCP4.5 climate warming scenario,highlighting the importance of developing adaptive policies to address the growing risks associated with future LES.
基金Supported by the National Natural Science Foundation of China (41865003)Key Lab of Poyang Lake Wetland and Watershed Research of Ministry of Eduction (Jiangxi Normal University)(PK2022005)。
文摘In this study, high-resolution weather research and forecasting(WRF) simulations are used to explore the sensitivity of lake-effect convection over Poyang Lake(PL) to the change of lake surface temperature(LST). A control experiment(CTR) with climate mean LST(303 K) is compared with six sensitivity experiments(CTR-1/2/3K and CTR+1/2/3K) in which the LSTs are set based on the mean LST difference of 6 K between the maximum and minimum. The results show that the CTR experiment reasonably reproduces the lake-effect convection, and the lake-effect convection in sensitivity experiments is significantly influenced by the LST. With the increase of LST, the initiation time of the lake-effect convection is advanced gradually, while the initiation location moves PL from its shore.The lake-effect convection strengthens(weakens) in the increase-temperature CTR+1/2/3K(decrease-temperature CTR-1/2/3K) experiments, but the lake-effect convection does not monotonically strengthen with the LST, for the strongest one occurring in the CTR+1K experiment. The corresponding diagnostic analysis shows that the upward sensible heat flux and latent heat flux over PL increase with the LST, resulting in the enhancement of the lake-land breeze and the enlargement of the convective available potential energy(CAPE). This is the main reason for the changes in the initiation time and location, as well as the intensity of lake-effect convection in different experiments.In addition, the non-monotonous variation of the level of free convection, which is mainly induced by the non-monotonous variation of the lifting condensation level, is responsible for the non-monotonous variation of the lake-effect convection intensity with the LST.
