径潮共同作用对径流型河口盐水上溯的影响
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摘要
为进一步认识径流型河口枯季盐水上溯距离变化的影响因素及其作用机制,将实际河口简化并在不同径流量下分别用等潮差正弦潮和主要分潮驱动,进行盐水三维数值模拟试验。结果表明:随着径流和潮汐两大基本作用的相对强度不同,平衡态下盐水形态和位置自动调整并最终达到盐输运平衡,径流量小于3 000 m3/s且潮差小于2 m时,最大上溯距离随潮差的变化规律在不同径流量下存在明显差别;大小潮半月周期内盐水呈现非平衡态,非强混合时潮周期盐水上溯最大距离围绕平衡态随潮差呈顺时针绳套关系变化。径流导致的密度环流作用和潮汐的混合作用交织,两者相互影响并协同发展,两种作用相对强度的不同是导致径流型河口盐水上溯距离变化显著的主导因素。
In order to further understand the leading influential driving forces and their cooperative mechanism in saltwater intrusion of riverine estuaries in dry season,3-D numerical simulation experiments were conducted in this study with a simplified estuary which was forced by sinusoidal tides of constant tidal ranges and main tidal constituents respectively at different runoff flow. The results indicate that in tidal saline equilibrium,with variation of relative strength of the runoff and tide,the shape and the location of salt water intrusion are automatically adjusted and end with balanced salt transportation. When the runoff rates are less than 3 000 m3/s and tidal ranges less than 2 m,there are obvious differences in the variability of maximum intrusion lengths with tides under different runoff flow. For weak mixing estuary,during the period time of spring and neap,the saline water presents fortnight non-equilibrium and their data points of tidal maximum intrusion length with respect to tidal range change clockwise like a loop around that of the equilibrium state. The density circulation induced by runoff and the tidal mixing collaborate and develop with interaction. The contrast of their intensity dominates the significant distinction of saline intrusion length in riverine estuaries.
In order to further understand the leading influential driving forces and their cooperative mechanism in saltwater intrusion of riverine estuaries in dry season,3-D numerical simulation experiments were conducted in this study with a simplified estuary which was forced by sinusoidal tides of constant tidal ranges and main tidal constituents respectively at different runoff flow. The results indicate that in tidal saline equilibrium,with variation of relative strength of the runoff and tide,the shape and the location of salt water intrusion are automatically adjusted and end with balanced salt transportation. When the runoff rates are less than 3 000 m3/s and tidal ranges less than 2 m,there are obvious differences in the variability of maximum intrusion lengths with tides under different runoff flow. For weak mixing estuary,during the period time of spring and neap,the saline water presents fortnight non-equilibrium and their data points of tidal maximum intrusion length with respect to tidal range change clockwise like a loop around that of the equilibrium state. The density circulation induced by runoff and the tidal mixing collaborate and develop with interaction. The contrast of their intensity dominates the significant distinction of saline intrusion length in riverine estuaries.
引文
[1]KRANENBURG C.A time scale for long-term salt intrusion in well-mixed estuaries[J].Journal of Physical Oceanography,1986,16(7):1329-1331.
[2]MACCREADY P.Toward a unified theory of tidally-averaged estuarine salinity structure[J].Estuaries and Coasts,2004,27(4):561-570.
[3]MACCCREADY P,GEYER W R.Advances in estuarine physics[J].Ann Rev Mar Sci,2010,2(1):35-58.
[4]卢陈,袁丽蓉,高时友,等.潮汐强度与咸潮上溯距离试验[J].水科学进展,2013,24(2):251-257.(LU C,YUAN L R,GAO S Y,et al.Experimental study on the relationship between tide strength and salt intrusion length[J].Advances in Water Science,2013,24(2):251-257.(in Chinese))
[5]卢陈,刘晓平,陈荣力,等.径流-潮汐相互作用与咸潮上溯距离试验研究[J].水动力学研究与进展,2014,29(3):282-288.(LU C,LIU X P,CHEN R L,et al.Experimental study on the interaction of runoff-tide and salt water intrusion length[J].Chinese Journal of Hydrodynamics,2014,29(3):282-288.(in Chinese))
[6]LERCZAK J A,GEYER W R,RALSTON D K.The temporal response of the length of a Partially stratified estuary[J].Journal of Physical Oceanography,2009,39(1):1-25.
[7]BANAS N S,HICKEY B M,MACCREADY P,et al.Dynamics of Willapa Bay,Washington,a highly unsteady partially mixed estuary[J].Journal of Physical Oceanography,2004,34(11):2413-2427.
[8]JAY D A,SMITH J D.Circulation,density distribution and neap-spring transitions in the Columbia River Estuary[J].Progress in Oceanography,1990,25(1):81-112.
[9]BOWEN M M,GEYER W R.Salt transport and the time-dependent salt balance of a partially stratified estuary[J].Journal of Geophysical Research Atmospheres,2003,108(C5):249-260.
[10]高时友,陈子燊.珠江口磨刀门水道枯季咸潮上溯与盐度输运机理分析[J].海洋通报,2016,35(6):625-631.(GAO S Y,CHEN Z S.Analysis on salinity transport mechanism for the Modaomen waterway of Pearl River in the dry season[J].Marine Science Bulletin,2016,35(6):625-631.(in Chinese))
[11]NAKAYAMA K,OKADA T,NOMURA M.Mechanism responsible for fortnightly modulations in estuarine circulation in Tokyo Bay[J].Estuarine Coastal&Shelf Science,2005,64(2/3):459-466.
[12]GONG W,MAA P Y,HONG B,et al.Salt transport during a dry season in the Modaomen Estuary,Pearl River Delta,China[J].Ocean&Coastal Management,2014,100:139-150.
[13]LI M,ZHONG L.Flood-ebb and spring-neap variations of mixing,stratification and circulation in Chesapeake Bay[J].Continental Shelf Research,2009,29(1):4-14.
[14]陈文龙,邹华志,董延军.磨刀门水道咸潮上溯动力特性分析[J].水科学进展,2014,25(5):713-723.(CHEN W L,ZOU H Z,DONG Y J.Hydrodynamic of saltwater intrusion in the Modaomen waterway[J].Advances in Water Science,2014,25(5):713-723.(in Chinese))
[15]HETLAND R D,GEYER R W.An idealized study of long,partially mixed estuaries[J].Journal of Physical Oceanography,2004,34(12):2677-2691.
[16]郭振仁,袁丽蓉.河口咸潮活动及其环境影响:珠江口咸潮上溯问题与对策[M].北京:中国环境科学出版社,2012:61-72.(GUO Z R,YUAN L R.Salt tide activity and environmental impact in estuarine:the problems and countermeasures of salt tideinvasion in the Pearl River estuary[M].Beijing:China Environmental Science Press,2012:61-72.(in Chinese))
[17]苏波,何用,卢陈,等.磨刀门咸潮入侵与抑咸技术[M].北京:中国水利水电出版社,2013:45-48.(SU B,HE Y,LU C,et al.Salt tide invasion and saltwater tide control for the Modaomen waterway[M].Beijing:China Water&Power Press,2013:45-48.(in Chinese))
[18]DYER K R.Estuaries:a physical introduction[M].2nd Ed.Chichester:Wiley,1997.
[19]HUPPERT H E.Gravity currents:a personal perspective[J].Journal of Fluid Mechanics,2006,554:299-322.
[2]MACCREADY P.Toward a unified theory of tidally-averaged estuarine salinity structure[J].Estuaries and Coasts,2004,27(4):561-570.
[3]MACCCREADY P,GEYER W R.Advances in estuarine physics[J].Ann Rev Mar Sci,2010,2(1):35-58.
[4]卢陈,袁丽蓉,高时友,等.潮汐强度与咸潮上溯距离试验[J].水科学进展,2013,24(2):251-257.(LU C,YUAN L R,GAO S Y,et al.Experimental study on the relationship between tide strength and salt intrusion length[J].Advances in Water Science,2013,24(2):251-257.(in Chinese))
[5]卢陈,刘晓平,陈荣力,等.径流-潮汐相互作用与咸潮上溯距离试验研究[J].水动力学研究与进展,2014,29(3):282-288.(LU C,LIU X P,CHEN R L,et al.Experimental study on the interaction of runoff-tide and salt water intrusion length[J].Chinese Journal of Hydrodynamics,2014,29(3):282-288.(in Chinese))
[6]LERCZAK J A,GEYER W R,RALSTON D K.The temporal response of the length of a Partially stratified estuary[J].Journal of Physical Oceanography,2009,39(1):1-25.
[7]BANAS N S,HICKEY B M,MACCREADY P,et al.Dynamics of Willapa Bay,Washington,a highly unsteady partially mixed estuary[J].Journal of Physical Oceanography,2004,34(11):2413-2427.
[8]JAY D A,SMITH J D.Circulation,density distribution and neap-spring transitions in the Columbia River Estuary[J].Progress in Oceanography,1990,25(1):81-112.
[9]BOWEN M M,GEYER W R.Salt transport and the time-dependent salt balance of a partially stratified estuary[J].Journal of Geophysical Research Atmospheres,2003,108(C5):249-260.
[10]高时友,陈子燊.珠江口磨刀门水道枯季咸潮上溯与盐度输运机理分析[J].海洋通报,2016,35(6):625-631.(GAO S Y,CHEN Z S.Analysis on salinity transport mechanism for the Modaomen waterway of Pearl River in the dry season[J].Marine Science Bulletin,2016,35(6):625-631.(in Chinese))
[11]NAKAYAMA K,OKADA T,NOMURA M.Mechanism responsible for fortnightly modulations in estuarine circulation in Tokyo Bay[J].Estuarine Coastal&Shelf Science,2005,64(2/3):459-466.
[12]GONG W,MAA P Y,HONG B,et al.Salt transport during a dry season in the Modaomen Estuary,Pearl River Delta,China[J].Ocean&Coastal Management,2014,100:139-150.
[13]LI M,ZHONG L.Flood-ebb and spring-neap variations of mixing,stratification and circulation in Chesapeake Bay[J].Continental Shelf Research,2009,29(1):4-14.
[14]陈文龙,邹华志,董延军.磨刀门水道咸潮上溯动力特性分析[J].水科学进展,2014,25(5):713-723.(CHEN W L,ZOU H Z,DONG Y J.Hydrodynamic of saltwater intrusion in the Modaomen waterway[J].Advances in Water Science,2014,25(5):713-723.(in Chinese))
[15]HETLAND R D,GEYER R W.An idealized study of long,partially mixed estuaries[J].Journal of Physical Oceanography,2004,34(12):2677-2691.
[16]郭振仁,袁丽蓉.河口咸潮活动及其环境影响:珠江口咸潮上溯问题与对策[M].北京:中国环境科学出版社,2012:61-72.(GUO Z R,YUAN L R.Salt tide activity and environmental impact in estuarine:the problems and countermeasures of salt tideinvasion in the Pearl River estuary[M].Beijing:China Environmental Science Press,2012:61-72.(in Chinese))
[17]苏波,何用,卢陈,等.磨刀门咸潮入侵与抑咸技术[M].北京:中国水利水电出版社,2013:45-48.(SU B,HE Y,LU C,et al.Salt tide invasion and saltwater tide control for the Modaomen waterway[M].Beijing:China Water&Power Press,2013:45-48.(in Chinese))
[18]DYER K R.Estuaries:a physical introduction[M].2nd Ed.Chichester:Wiley,1997.
[19]HUPPERT H E.Gravity currents:a personal perspective[J].Journal of Fluid Mechanics,2006,554:299-322.