全部 标题 作者
关键词 摘要

OALib Journal期刊
ISSN: 2333-9721
费用:99美元

查看量下载量

相关文章

更多...
科学通报  2012 

潮滩动力过程影响下扩散边界层和沉积物-水界面扩散通量的变化

, PP. 656-665

Keywords: 扩散边界层,扩散通量,动力过程,溶解氧,微尺度剖面仪,潮滩

Full-Text   Cite this paper   Add to My Lib

Abstract:

扩散边界层(DBL)控制了沉积物和上覆水间物质的交换,在潮流底边界层(BBL)的动力过程影响下,海洋DBL的厚度变化很大,溶解物质的扩散通量也有很大变化.因此探究影响DBL厚度和扩散通量变化的动力机制是准确估算扩散通量的关键前提,对近海水体营养盐补充和环境二次污染等问题的准确估计有重要意义.利用微尺度剖面仪和高频流速仪等对BBL的动力结构和DBL进行了联合观测.运用线性分布、剖面拐点和浓度方差法较准确地判识了DBL厚度.分别从水体和沉积物一侧计算了扩散通量,两者相差不超过6%.使用PROFILE模式对溶解氧剖面进行了精确模拟,获得了分层的单位体积耗氧速率.结果显示DBL厚度(0.10~0.35mm)和扩散通量(15.4~53.6mmolm-2d-1)在一个潮周期内均变化了3.5倍.通过进一步分析动力强迫对DBL厚度和扩散通量的影响,发现在平均流速控制DBL厚度占优的潮滩系统中,DBL厚度δDBL和平均流速大小U成反比,通过拟合得到了两者的关系式δDBL=1686.1DU-1+0.1(其中D为分子扩散系数).扩散通量的变化分阶段受到了沉积物上覆海水和湍流混合强度变化的影响.在主要受湍流混合影响的阶段,扩散通量和湍动能耗散率、摩擦速度和湍动能的变化都有一定的正相关关系.

References

[1]  6 Higashino M, O'Connor B L, Hondzo M, et al. Oxygen transfer from flowing water to microbes in an organic sediment bed. Hydrobiologia,2008, 614: 219-231??
[2]  7 Berg P, Glud R N, Hume A, et al. Eddy correlation measurements of oxygen uptake in deep ocean sediments. Limnol Oceanogr-Meth, 2009, 7:576-584??
[3]  14 Steinberger N, Hondzo M. Diffusional mass transfer at sediment-water interface. J Environ Eng, 1999, 125: 192-200??
[4]  15 Reimers C E, Fischer K M, Merewether R, et al. Oxygen microprofiles measured in situ in deep ocean sediments. Nature, 1986, 320: 741-744??
[5]  18 Lorke A, Müller B, Maerki M, et al. Breathing sediments: The control of diffusive transport across the sediment-water interface by periodic boundary-layer turbulence. Limnol Oceanogr, 2003, 48: 2077-2085??
[6]  19 Liu Z, Wei H. Estimation to the turbulent kinetic energy dissipation rate and bottom shear stress in the tidal bottom boundary layer of the Yellow Sea. Prog Nat Sci, 2007, 17: 289-297??
[7]  20 R?y H, Huettel M, J?rgensen B B. Transmission of oxygen concentration fluctuations through the diffusive boundary layer overlying aquatic sediments. Limnol Oceanogr, 2004, 49: 686-692??
[8]  21 Berg P, Risgaard-Petersen N, Rysgaard S. Interpretation of measured concentration profiles in sediment pore water. Limnol Oceanogr, 1998,43: 1500-1510??
[9]  27 Hearn C J, Robson J. Modelling a bottom diurnal boundary layer and its control of massive alga blooms in an estuary. Appl Math Mod, 2000,24: 843-859??
[10]  28 Lozovatsky I D, Liu Z, Wei H, et al. Tides and mixing in the northwestern East China Sea Part I: Rotating and reversing flows. Cont Shelf Res,2008, 28: 318-337??
[11]  3 汪亚平, 高抒, 贾建军. 海底边界层水流结构及底移质搬运研究进展. 海洋地质与第四纪地质, 2000, 3: 101-106
[12]  4 Higashino M, Stefan H G, Gantzer C J. Periodic diffusional mass transfer near sediment/water interface: Theory. J Environ Eng, 2003, 129:447-455??
[13]  5 Higashino M, Gantzer C J, Stefan H G. Unsteady diffusional mass transfer at the sediment/water interface: Theory and significance for SOD measurement. Water Res, 2004, 38: 1-12??
[14]  8 Bryant L D, Lorrai C, McGinnis D F, et al. Variable sediment oxygen uptake in response to dynamic forcing. Limnol Oceanogr, 2010, 55:950-964??
[15]  9 张兆顺, 崔桂香, 许春晓. 湍流理论与模拟. 北京: 清华大学出版社, 2005. 98-102
[16]  10 J?rgensen B B, Des Marais D J. The diffusive boundary layer of sediments: Oxygen microgradients over a microbial mat. Limnol Oceanogr,1990, 35: 1343-1355??
[17]  11 R?y H, Hüttel M, J?rgensen B B. The role of small-scale sediment topography for oxygen fluxes across the diffusive boundary layer. Limnol Oceanogr, 2002, 47: 837-847??
[18]  12 Sweerts J-P R A, Louis V S T, Cappenberg T E. Oxygen concentration profiles and exchange in sediment cores with circulated overlying water. Freshwater Biol, 1989, 21: 401-409??
[19]  13 Hondzo M. Dissolved oxygen transfer at the sediment-water interface in a turbulent flow. Water Resour Res, 1998, 34: 3525-3533??
[20]  16 Archer D, Emerson S, Smith C R. Direct measurement of the diffusive sublayer at the deep sea floor using oxygen microelectrodes. Nature,1989, 340: 623-626??
[21]  17 Glud R N, Stahl H, Berg P, et al. In situ microscale variation in distribution and consumption of O2: A case study from a deep ocean margin sediment (Sagami Bay, Japan). Limnol Oceanogr, 2009, 54: 1-12??
[22]  22 Ramsing N, Gundersen J. Seawater and gases—Tabulated physical parameters of interest to people working with microsensors in marine systems. Version 2.0. Unisense Internal Report. 1994
[23]  23 Liu H, Wu C, Xu W, et al. Contrasts between estuarine and river systems in near-bed turbulent flows in the Zhujiang (Pearl River) Estuary, China. Estuar Coast Shelf S, 2009, 83: 591-601??
[24]  24 Wu J, Liu H, Ren J, et al. Cyclonic spirals in tidally accelerating bottom boundary layers in the Zhujiang (Pearl River) Estuary. J Phys Oceanogr, 2011, 41: 1209-1226??
[25]  25 汪亚平, 高抒, 贾建军. 浪流联合作用下潮滩沉积动力过程的高分辨率数据采集与分析. 科学通报, 2006, 51: 339-348
[26]  26 Lorenzen J, Larsen L H, Kjar T, et al. Biosensor determination of the microscale distribution of nitrate, nitrate assimilation, nitrification and denitrification in a diatom-inhabited freshwater sediment. Appl Environ Microbiol, 1998, 64: 3264-3269
[27]  1 J?rgensen B B, Revsbech N P. Diffusive boundary layers and the oxygen uptake of sediments and detritus. Limnol Oceanogr, 1985, 30:111-122??
[28]  2 Gundersen J K, J?rgensen B B. Microstructure of diffusive boundary layers and the oxygen uptake of the sea floor. Nature, 1990, 345:604-607??

Full-Text

comments powered by Disqus

Contact Us

service@oalib.com

QQ:3279437679

WhatsApp +8615387084133