In the context of global warming, the increasing wildfire frequency has become a critical climate research focus in North America. This study used the Community Earth System Model(CESM 1.2) to investigate the impacts ...In the context of global warming, the increasing wildfire frequency has become a critical climate research focus in North America. This study used the Community Earth System Model(CESM 1.2) to investigate the impacts of 20thcentury wildfires on North American climate and hydrology. Summer represents the peak wildfire season in North America, with the Gulf of Mexico and Midwest regions experiencing the most severe effects. Wildfires not only damage vegetation during the fire season but also extend prolonged impacts into non-fire periods, showing distinct seasonal variations. In spring, wildfires increase surface albedo, triggering a cooling effect through enhanced snow cover and delayed snowmelt. Conversely, summer and autumn surface warming stems primarily from wildfire-suppressed vegetation transpiration. Warming near the Gulf of Mexico enhances moisture transport and precipitation, particularly in summer and autumn. Reduced evaporation and increased precipitation from the Gulf of Mexico significantly altered the hydrological cycle across North America, leading to increased runoff continent-wide.展开更多
采用多元统计方法分析了雷州半岛滨海湿地表层沉积物中重金属的含量、相关性、空间分布特征和来源,并对其生态风险进行了评价。研究区表层沉积物中的Cu、Zn、Pb、Cr、As、Cd和Hg的含量平均值分别为10.29±7.80、47.06±28.47、2...采用多元统计方法分析了雷州半岛滨海湿地表层沉积物中重金属的含量、相关性、空间分布特征和来源,并对其生态风险进行了评价。研究区表层沉积物中的Cu、Zn、Pb、Cr、As、Cd和Hg的含量平均值分别为10.29±7.80、47.06±28.47、24.74±10.78、41.70±26.25、7.98±4.73、0.042±0.029和0.020±0.027μg·g-1。Cu、Zn和Cr以及Pb、Cd和Hg为2个强正相关群,第一个群中的重金属元素以自然来源为主,第二个群则兼有人为输入和自然2个来源。重金属含量的高值区主要分布在流沙港、湛江港西部、海安港和雷州湾西部海域。对照美国海洋与大气管理局(NOAA)的生物效应标准,研究区绝大部分海域内的表层沉积物中除As含量在约50%的站位的值在"效应范围低"(effect range low)和"效应范围中等"(effect range median)阈值之间,对底栖生物会偶尔发生负面效应外,其他重金属基本不发生负面效应。重金属总体为低污染程度和低潜在生态风险。应重视人类活动较强的区域如湛江港西部、流沙港、海安港等海区的重金属污染,以避免持续累积至能对生物造成危害的水平。展开更多
基金National Natural Science Foundation of China(42175022)。
文摘In the context of global warming, the increasing wildfire frequency has become a critical climate research focus in North America. This study used the Community Earth System Model(CESM 1.2) to investigate the impacts of 20thcentury wildfires on North American climate and hydrology. Summer represents the peak wildfire season in North America, with the Gulf of Mexico and Midwest regions experiencing the most severe effects. Wildfires not only damage vegetation during the fire season but also extend prolonged impacts into non-fire periods, showing distinct seasonal variations. In spring, wildfires increase surface albedo, triggering a cooling effect through enhanced snow cover and delayed snowmelt. Conversely, summer and autumn surface warming stems primarily from wildfire-suppressed vegetation transpiration. Warming near the Gulf of Mexico enhances moisture transport and precipitation, particularly in summer and autumn. Reduced evaporation and increased precipitation from the Gulf of Mexico significantly altered the hydrological cycle across North America, leading to increased runoff continent-wide.
文摘采用多元统计方法分析了雷州半岛滨海湿地表层沉积物中重金属的含量、相关性、空间分布特征和来源,并对其生态风险进行了评价。研究区表层沉积物中的Cu、Zn、Pb、Cr、As、Cd和Hg的含量平均值分别为10.29±7.80、47.06±28.47、24.74±10.78、41.70±26.25、7.98±4.73、0.042±0.029和0.020±0.027μg·g-1。Cu、Zn和Cr以及Pb、Cd和Hg为2个强正相关群,第一个群中的重金属元素以自然来源为主,第二个群则兼有人为输入和自然2个来源。重金属含量的高值区主要分布在流沙港、湛江港西部、海安港和雷州湾西部海域。对照美国海洋与大气管理局(NOAA)的生物效应标准,研究区绝大部分海域内的表层沉积物中除As含量在约50%的站位的值在"效应范围低"(effect range low)和"效应范围中等"(effect range median)阈值之间,对底栖生物会偶尔发生负面效应外,其他重金属基本不发生负面效应。重金属总体为低污染程度和低潜在生态风险。应重视人类活动较强的区域如湛江港西部、流沙港、海安港等海区的重金属污染,以避免持续累积至能对生物造成危害的水平。
