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Recently, the accumulation of plastic debris in the marine environment has become a great concern worldwide. Although plastics are biologically and chemically inert, plastic debris has been suspected of causing adverse effects on ecosystems due to the increase in reactivity by size reduction and/or micropollutants associated with plastics. Because of the high sorption capacity of microplastics toward organic micropollutants, it is suspected that microplastics may play roles in the distribution and fate of micropollutants. In order to quantitatively evaluate the “net flow” of environmental contaminants in water-plastic-organism systems, a fugacity analysis was conducted using concentrations of polycyclic aromatic hydrocarbons (PAHs) in open oceans and in polyethylene as a representative material of plastic debris. Ratio of fugacity in polyethylene to that in seawater showed a decreasing trend with increasing partition coefficient between polyethylene and seawater (KPE/sw). This indicates that phase equilibrium between polyethylene and seawater is not attained for higher molecular weight PAHs. Disequilibrium of high molecular weight PAHs suggests that transfer from seawater to plastic debris is thermodynamically driven and the role of plastic debris as a vector to transfer them to living organisms would be minimal. However, additives may slowly migrate from plastics into the environment causing potentially serious effects on ecosystems. 相似文献
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Observed summer (May–October) rainfall in Myanmar for the period 1981–2010 was used to investigate the interannual variability of summer monsoon rainfall over Myanmar. Empirical orthogonal function, the sequential Mann-Kendall test, power spectrum analysis, and singular value decomposition (SVD) were deployed in the study. Results from spectral analysis showed that the variability of rainfall over Myanmar exhibits a 2- to 6-year cycle. An abrupt change in rainfall over the country was noted in 1992. There was a notable increasing rainfall trend from 1989. After the sudden change, the mean rainfall increased by 36.1 mm, compared with the mean rainfall before the sudden change, and was associated with a rise in temperature of about 0.2 °C. An increase in heavy rainfall days was observed from the early 1990s to 2010. IOD and ENSO play an important role in the interannual variability of the summer rainfall over Myanmar. The covariability between rainfall over Myanmar and Indian Ocean SST generally suggests that a positive IOD mode is associated with suppressed rainfall in the central and northern parts of Myanmar. During a negative IOD mode, nearly the whole Myanmar experiences enhanced rainfall, which is associated with devastating socioeconomic impacts. The covariability between the rainfall over Myanmar and the sea surface temperature in the Pacific Ocean in the first and second SVD modes was dominated by warming in the east and central Pacific—an El Niño-like pattern—resulting in dry conditions in central Myanmar. 相似文献
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本文系统报道了缅甸抹谷变质带中部Yinmabin花岗闪长岩体及其基性岩墙的主量元素、微量元素及锆石U-Pb年龄和Lu-Hf同位素组成,重点讨论了花岗闪长岩和基性岩墙的岩石成因、物质来源及其地质意义。抹谷Yinmabin花岗闪长岩体主量元素显示富钠(N2O/K2O=1.5~1.75)、准铝(ACNK=0.94~0.97)和钙碱性岩石系列的地球化学特征。样品富集轻稀土(LREE)元素、大离子亲石元素(LILE),相对亏损高场强元素(HFSE)。岩体的主、微量元素地球化学特征均显示其具有活动陆缘I型花岗岩的地球化学属性。抹谷Yinmabin花岗闪长岩的锆石U-Pb年龄为131~135 Ma,其εHf(t)值在-15.66~-2.99之间,平均值为-8.77,单阶段模式年龄(tDM)为795~1569 Ma;而后期侵位的辉绿岩的锆石U-Pb年龄为120~118 Ma,其εHf(t)值在-13.72~+5.82之间,平均值为-2.72,单阶段模式年龄(tDM)为570~1341 Ma,表明这些岩石可能主要来源于古老下地壳部分熔融但同时也受到地幔物质的加入混染。与滇西以及北拉萨岩浆带的Lu-Hf同位素特征十分相近,暗示抹谷-毛淡棉地块早白垩世岩浆岩带与波密-察隅-高黎贡-拉萨岩浆岩带形成环境相似,可能是腾冲岩浆岩带向南延伸的一部分。结合岩石成因、源区性质和区域构造演化,认为抹谷花岗闪长岩体及基性岩墙的形成与中特提斯洋板块的俯冲作用密切相关,同时俯冲-碰撞转换的时限应该在120 Ma左右。这对于研究抹谷地体在中生代期间中特提斯洋俯冲碰撞过程具有重要的地质意义。 相似文献
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徐经纬 徐敏 蒋熹 ArmelleReca C. Remedio Dmitry V. Sein Nikolay Koldunov Daniela Jac 《气候变化研究进展》2016,12(4):286-293
采用泰勒图和偏差分析等统计方法,评估分析了德国区域气候模式（REMO）对中国1989-2008年气温和降水的模拟能力。结果表明：REMO气温模拟值与观测值空间相关系数为0.94,降水空间相关系数较低（0.42）,气温模拟结果明显优于降水;从空间偏差上看,在中国大部分地区,REMO模拟的气温高于观测值,偏差在±4℃以内,青藏高原整体有明显的-4～-2℃的冷偏差;模拟的降水值则高于观测值,空间偏差分布较均匀,中国大部分地区偏差在±300 mm之内;除青藏高原、华南和西南地区外,REMO能较准确地反映出中国气温和降水的空间分布特征,其中华北和东北地区模拟效果最好;REMO对夏季气温和冬季降水的模拟能力相对较好;REMO在地形起伏较大地区的模拟能力有待提高。 相似文献
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Zhang Ji’en Xiao Wenjiao Windley Brian F. Cai Fulong Sein Kyaing Naing Soe 《International Journal of Earth Sciences》2017,106(4):1391-1408
International Journal of Earth Sciences - The Indo-Burma Range (IBR) of Myanmar, the eastern extension of the Yarlung-Tsangpo Neotethyan belt of Tibet in China, contains mélanges with... 相似文献
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Chen Si Chen Yi Li Yibing Su Bin Zhang Qinghua Aung Me Me Sein Kyaing 《中国科学:地球科学(英文版)》2021,64(11):1873-1892
Science China Earth Sciences - Ultrahigh-temperature (UHT) metamorphism is critical for understanding the most extreme thermal evolution of continental crust. However, UHT metamorphism... 相似文献
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de la Vara Alba Cabos William Sein Dmitry V. Sidorenko Dmitry Koldunov Nikolay V. Koseki Shunya Soares Pedro M. M. Danilov Sergey 《Climate Dynamics》2020,54(11-12):4733-4757
Climate Dynamics - Despite the efforts of the modelling community to improve the representation of the sea surface temperature (SST) over the South Eastern Tropical Atlantic, warm biases still... 相似文献
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Modelling Indonesian rainfall with a coupled regional model 总被引：2，自引：0，他引：2
Edvin Aldrian Dmitry Sein Daniela Jacob Lydia Dümenil Gates Ralf Podzun 《Climate Dynamics》2005,25(1):1-17
Long-term high-resolution coupled climate model simulations using the Max Planck Institute Regional Climate Model and the
Max Planck Institute Ocean Model have been performed with boundary forcings from two reanalyses: firstly from the European
Centre for Medium-Range Weather Forecasts, and secondly from the joint reanalysis of the National Centers for Environmental
Prediction and the National Center for Atmospheric Research. This study employs a special coupling setup using a regional
atmospheric model and a global ocean model. The latter model applies a special conformal grid from a bipolar orthogonal spherical
coordinate system, which allows irregular positions of the poles and focuses on the detail over the Maritime Continent. The
coupled model was able to simulate stable and realistic rainfall variabilities without flux correction and at two different
ocean resolutions. The coupled system is integrated for a period between 1979 and 1993 and the results are then compared to
those from uncoupled runs and from observation. The results show improved performance after coupling: a remarkable reduction
of overestimated rainfall over the sea for the atmospheric model and of warm SST biases for the ocean model. There is no significant
change in rainfall variability at higher ocean model resolution, but the ocean circulation shows less transport variability
within the Makassar Strait in comparison to observations.
This paper has not been published or considered by any other journal in any language. 相似文献
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