查干湖是吉林省内最大的天然湖泊,监测其湖面温度及其变化是研究湖泊环境对气候变化响应机制不可或缺的内容.本文利用2001年至2020年MODIS L3级地表温度产品(MOD11A2)获取查干湖表面温度(Lake water surface temperature,LWST)时间序列...查干湖是吉林省内最大的天然湖泊,监测其湖面温度及其变化是研究湖泊环境对气候变化响应机制不可或缺的内容.本文利用2001年至2020年MODIS L3级地表温度产品(MOD11A2)获取查干湖表面温度(Lake water surface temperature,LWST)时间序列,分析近20年查干湖湖表温度变化特征及其影响因素.结果表明,查干湖冰封期年均湖表温度呈先下降再上升态势.2012年平均温度最低为-17.65℃,是20年温度变化的转折点;昼夜温差与冰期趋势一致呈缓慢下降趋势,在2020年昼夜温差已降至-10.27℃;近20年间查干湖冰封期逐年缩短,平均每年143天,最短在2019年冰封期仅有125天;MODIS LWST产品反演的湖表温度精度足够,置信水平为99%;查干湖湖表温度在气象影响方面,气温与地温的变化是最相关性的影响因子,相关系数大于0.9,且P小于0.001.展开更多
Pavement surface friction is a significant factor for driving safety and plays a critical role in reducing wet- pavement crashes. However, the current asphalt mixture design procedure does not directly consider fricti...Pavement surface friction is a significant factor for driving safety and plays a critical role in reducing wet- pavement crashes. However, the current asphalt mixture design procedure does not directly consider friction as a requirement. The objective of this study was to develop a surface friction prediction model that can be used during a wearing course mixture design. To achieve the objective, an experimental study was conducted on the frictional characteristics of typical wearing course mixtures in Louisiana. Twelve wearing course mixtures including dense-graded and open-graded mixes with different combinations of aggregate sources were evaluated in laboratory using an accelerated polishing and testing procedure considering both micro- and macro texture properties. In addition, the surface frictional properties of asphalt mixtures were measured on twenty-two selected asphalt pavement sections using different in situ devices including Dynamic Friction Tester （DFT）, Circular Texture Meter （CTM）, and Lock-Wheel Skid Trailer （LWST）. The results have led to develop a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend polish stone value, gradation parameters, and traffic, which is suited in checking whether the selected aggregates in a wearing course mix design would meet field friction requirements under a certain design traffic polishing.展开更多
文摘Pavement surface friction is a significant factor for driving safety and plays a critical role in reducing wet- pavement crashes. However, the current asphalt mixture design procedure does not directly consider friction as a requirement. The objective of this study was to develop a surface friction prediction model that can be used during a wearing course mixture design. To achieve the objective, an experimental study was conducted on the frictional characteristics of typical wearing course mixtures in Louisiana. Twelve wearing course mixtures including dense-graded and open-graded mixes with different combinations of aggregate sources were evaluated in laboratory using an accelerated polishing and testing procedure considering both micro- and macro texture properties. In addition, the surface frictional properties of asphalt mixtures were measured on twenty-two selected asphalt pavement sections using different in situ devices including Dynamic Friction Tester （DFT）, Circular Texture Meter （CTM）, and Lock-Wheel Skid Trailer （LWST）. The results have led to develop a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend polish stone value, gradation parameters, and traffic, which is suited in checking whether the selected aggregates in a wearing course mix design would meet field friction requirements under a certain design traffic polishing.
