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51.
Dry deposition velocities and fluxes of PM10during Asian dust events over the Yellow Sea from 2001 to 2007 were investigated using observation data in Qingdao, China and Jeju, Korea. The dry deposition velocities of PM10 during dust events over the Yellow Sea ranged from 0.19 to 8.17 cm/sec, with an average of 3.38 cm/sec. Dry deposition fluxes of PM10during dust events over the Yellow Sea were in the range of 68.5–2647.1 mg/(m2·day), with an average of 545.4 mg/(m2·day), which is 2–10 times higher than those reported by other studies for both dust and non-dust periods. It was estimated that 2.6 × 1011–48.7 × 1011g dust particles deposit to the Yellow Sea during dust events through dry deposition every year. Compared with the results in previous studies, it was found that the dry deposition of PM10over the Yellow Sea during dust events in the years with high frequency of dust could account for a large or overwhelming fraction of the annual total dry deposition. Backward air mass trajectory analysis showed that dust events influenced Jeju mainly originated from the desert regions located in Mongolia and Inner Mongolia, China. There were 119 backward trajectories influenced both Qingdao and Jeju during 15 dust events from 2001 to 2007, accounting for 61.3% of the total trajectories of 194, indicating that Qingdao and Jeju were usually on the same pathway of dust transport downwind from source areas. 相似文献
52.
Emission characteristics of carbon dioxide in the semiarid Stipa grandis steppe in Inner Mongolia, China 总被引:3,自引:1,他引:2
DONG Yun-she QI Yu-chun LIU Ji-yuan Manfred Domroes LIU Li-xin GENG Yuan-bo LIU Xing-ren YANG Xiao-hong LI Ming-feng 《环境科学学报(英文版)》2006,18(3):488-494
Introduction The emission and absorption of greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) etc. by soil is one of the hot topics on global change research, more and more attention has been paid to the flux measurement… 相似文献
53.
颗粒态重金属通过河流与大气向海洋输送 总被引:8,自引:2,他引:8
本文综述了河流与大气向海洋输送颗态重金属的过程、特点及输送通量、参考文献83篇。 相似文献
54.
于2018年1—12月,采集太湖湖滨及湖面共计9个点位600多个干湿沉降样品,估算了N、P干、湿沉降率以及全太湖2018年N、P干、湿沉降通量。结果表明,2018年太湖TN和TP月湿沉降率均值分别为161. 2和7. 1 kg/(km~2·月),TN和TP月干沉降率均值分别为103. 6和4. 5 kg/(km~2·月)。TN和TP年干沉降率空间分布规律为:湖面之上开阔水域处的TN和TP年干沉降率大于其他湖滨点位,TN和TP总沉降通量为7 702和333 t/a。2018年相比于2002—2003年,TN和TP总沉降通量分别降低了22. 6%和53. 8%。 相似文献
55.
Elani UA 《Environmental monitoring and assessment》2007,124(1-3):235-241
The ultraviolet UV solar radiation flux is monitored over a fixed time interval to study the daily, monthly and annual variations
for a nearly one decade in Riyadh. Mathematical expressions will be presented based on a comparison between theoretical and
experimental values. It is believed that the present analysis of UV radiation suggest that the environmental effects led to
a better understanding of UV scattering, UV reflection, ozone and clouds layers in Riyadh and other selected areas in the
mid-east region. 相似文献
56.
Georgios K. Sylaios Vassilios A. Tsihrintzis 《Environmental Modeling and Assessment》2009,14(1):59-72
The nutrient dynamics of the Strymonikos and Ierissos Gulfs, two semienclosed coastal water bodies, are studied using a simple
steady-state budget model, according to the Land–Ocean Interaction in the Coastal Zone modeling guidelines. Strymon river
plume dynamics prevailed in the area of the Inner and Outer Srymonikos Gulfs, comprising two layers, while the Ierissos Gulf
was defined as a one-box system. Seasonal and mean annual model input data for river discharge, precipitation, evaporation,
and concentrations of salt, phosphorus, and nitrogen were obtained during four field campaigns. Results from the nitrogen
and phosphorus cycling revealed the importance of river discharge in the horizontal and vertical transport of these substances
within the system. Furthermore, it occurred that the major biogeochemical transformation of nitrogen and phosphorus takes
place in the immediate nearshore zone (Inner Strymonikos Gulf), while the outer system sustains its nutrient dependence on
oceanic exchanges. Therefore, under the summer low flow conditions, the river-influenced inner system acts as a net source
of nitrogen and phosphorus, while under increased Strymon River discharge, phosphorus is transferred to the biological material
(and the sediments), and the system moves to an autotrophic state. The outer system showed an opposite behavior being autotrophic
throughout the year and heterotrophic in February. The Ierissos Gulf, a system not directly influenced by significant river
discharge, experienced a seasonally independent behavior with net heterotrophic and denitrification processes prevailing.
Model scenarios demonstrated that phosphate concentration increases, even under low river flow conditions and stimulates primary
production in excess of respiration, resulting in nitrogen fixation prevalence in the Inner Strymonikos Gulf. 相似文献
57.
7Be是研究大气科学与地球化学的核元素之一,对研究短期过程的地表土壤颗粒迁移具有较大价值。为了解南京地区利用7Be进行土壤侵蚀示踪研究的合适时机,于2010年1月~2011年12月收集南京地区各月的7Be沉降样品,经实验室化学实验处理和γ谱仪测量,计算7Be沉降通量,并分析7Be大气沉降的季节性变化趋势。结果表明:南京地区平均7Be沉降量为1 62178 Bq/(m2·a),沉降通量为066~1449 Bq/(m2·d),平均沉降通量为444 Bq/(m2·d);7Be沉降通量的季节变化呈现双峰型趋势,冬末春初和夏季是两个高值区;7Be沉降的а值冬春季较大,夏季最低;降雨量大小与沉降量存在明显的正相关 相似文献
58.
Marek MV Janouš D Taufarová K Havránková K Pavelka M Kaplan V Marková I 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1035-1039
By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. 相似文献
59.
60.
小浪底水库影响下的黄河花园口站和小浪底站pCO2特征及扩散通量 总被引:3,自引:3,他引:0
于2011年11月至2012年10月在黄河小浪底站和花园口站进行连续采样分析,根据亨利定律计算出表层水体二氧化碳分压(p CO2),研究了在小浪底水库"水沙调控"的影响下黄河花园口站和小浪底站表层水体p CO2特征及水-气CO2通量.结果表明,在小浪底水库正常调度期间,小浪底站表层水体p CO2在82~195 Pa之间,花园口站表层水体p CO2在99~228 Pa之间,且花园口站表层水体p CO2均高于同期的小浪底站;在小浪底水库调水调沙期间,两个水文站均表现为水库泄水期间的表层水体p CO2明显低于水库排沙期间的表层水体p CO2.无论是在小浪底水库正常调度期间还是在调水调沙期间,两个水文站表层水体p CO2均与DIC含量呈现显著的正相关关系.8、9月Ep CO2/AOU的比值高于生物好氧呼吸作用控制水体p CO2的理论下限0.62,因此8、9月生物好氧呼吸作用对水体p CO2的贡献比较明显.从全年来看小浪底站和花园口站平均水-气CO2扩散通量分别为0.486μmol·(m2·s)-1和0.588μmol·(m2·s)-1;在水库正常调度期间花园口站水-气CO2扩散通量明显高于同期的小浪底站;在小浪底水库调水调沙期间两个水文站均表现为水库泄水期间的水-气CO2扩散通量明显低于水库排沙期间的水-气CO2扩散通量. 相似文献