We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurife...We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurifera subsp. africana Maire（Cupressaceae） a rare medicinal tree, growing indigenously in Aures Mountains of Algeria. The precision of the results was assessed by analyzing the certified reference material IPE44（WEPAL）grass leaves. Results showed J. thurifera was characterized by high Cr and Mn contents. During autumn and winter mineral concentrations were higher in general. The levels of Cr, Se and Mn were higher during autumn and winter than during spring and summer. Zn contents were higher during summer than in other seasons. Cu content did not vary by season. The potential toxic elements in J. thurifera（Pb [ Cd [ Br） were below the permissible limits recommended by the Joint WHO/FAO guidelines except for Pb in autumn and winter.展开更多
基于1998—2017年海南岛地区18个台站逐日降水观测数据、TRMM逐日降水数据和ERA5再分析数据集等资料,使用资料统计分析和数值模式模拟等方法,对海南岛地区秋汛期形成原因进行了研究。观测分析表明,海南岛地区的降水随季节的变化与华南...基于1998—2017年海南岛地区18个台站逐日降水观测数据、TRMM逐日降水数据和ERA5再分析数据集等资料,使用资料统计分析和数值模式模拟等方法,对海南岛地区秋汛期形成原因进行了研究。观测分析表明,海南岛地区的降水随季节的变化与华南及同纬度带的其他地区存在显著差异,降水季节峰期出现在秋季,主要集中于9—10月。秋季,西南夏季风开始向东北冬季风转换,受其影响,海南岛地区上空处于偏东气流带中,秋汛期降水分布明显东多西少,且降水中心位于山前迎风坡一侧,东风气流在钟形地形的阻挡抬升作用下,致使其东部降水增多。此时秋季南海海表温度仍较高,有利于维持和增强海南岛秋季降水。通过WRF v4.3(Weather Research and Forecast Version 4.3)一系列的数值敏感性试验,验证了海南岛地形、海陆热力差异及南海较高的海温对海南岛秋汛期的形成起着决定性作用。展开更多
基金funded by Algerian Ministry of Higher Education and Scientific Research through the Project(CNEPRU No.D04N01UN170120140017)
文摘We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurifera subsp. africana Maire（Cupressaceae） a rare medicinal tree, growing indigenously in Aures Mountains of Algeria. The precision of the results was assessed by analyzing the certified reference material IPE44（WEPAL）grass leaves. Results showed J. thurifera was characterized by high Cr and Mn contents. During autumn and winter mineral concentrations were higher in general. The levels of Cr, Se and Mn were higher during autumn and winter than during spring and summer. Zn contents were higher during summer than in other seasons. Cu content did not vary by season. The potential toxic elements in J. thurifera（Pb [ Cd [ Br） were below the permissible limits recommended by the Joint WHO/FAO guidelines except for Pb in autumn and winter.
文摘基于1998—2017年海南岛地区18个台站逐日降水观测数据、TRMM逐日降水数据和ERA5再分析数据集等资料,使用资料统计分析和数值模式模拟等方法,对海南岛地区秋汛期形成原因进行了研究。观测分析表明,海南岛地区的降水随季节的变化与华南及同纬度带的其他地区存在显著差异,降水季节峰期出现在秋季,主要集中于9—10月。秋季,西南夏季风开始向东北冬季风转换,受其影响,海南岛地区上空处于偏东气流带中,秋汛期降水分布明显东多西少,且降水中心位于山前迎风坡一侧,东风气流在钟形地形的阻挡抬升作用下,致使其东部降水增多。此时秋季南海海表温度仍较高,有利于维持和增强海南岛秋季降水。通过WRF v4.3(Weather Research and Forecast Version 4.3)一系列的数值敏感性试验,验证了海南岛地形、海陆热力差异及南海较高的海温对海南岛秋汛期的形成起着决定性作用。
