1999年与2006年间夏季长江冲淡水变化动力因素的初步分析
A preliminary study on variations of the Changjiang Diluted Water between August 1999 and 2006
-
摘要: 根据径流量,1999年和2006年夏季的长江分别处于显著洪季和旱季.此期间的月平均风向也有显著区别.根据同期的海洋现场观测:相对1999年8月,2006年同期的长江口以东、以南毗邻水域表层盐度显著较高,而在长江口东北部海域则相对偏低;长江口附近海域的底层盐度有所偏高,但在浙江中南部沿海底层盐度则相对偏低.利用Regional Ocean Modelling Systems数值模式,对1999年和2006年实际的径流量、风场和黑潮及其分支变化等3个因素对长江冲淡水扩展的影响进行了一系列模拟试验和对比.对比试验表明:相对1999年8月,2006年夏季长江流量大幅度减小是长江口毗邻海域表层盐度升高的主要原因;风场是导致长江冲淡水相对偏北,并使长江口北部出现表层盐度负异常的主要因素;黑潮及其分支在东海北部入侵相对增强、在东海南部入侵相对减弱,使长江口南部表层盐度正异常海域扩大,并促使长江淡水向江口北部扩散增强、而向东部扩散减弱.长江口毗邻海域环流和水团的变化可能对夏季低氧区位置变化产生一定影响.Abstract: A large area hypoxia has been already reported respectively by two interdisciplinary surveys off the Chang jiang Estuary since summer of 1999 and 2006.The hypoxic zone shows distinct year-to-year variations.Observed oceanographic data are first analysized and reveals a big difference for the Chang jiang Diluted Water (CDW) between these two periods,either.These great changes are related to the tremendous reduction of the freshwater discharge and variations of wind fields between these two years.It is also found that the monthly mean intrusion of Kuroshio and its branches has increased in the north of East China Sea(ECS),but decreased in the south of ECS in August 2006 comparing with 1999 on the base of general circulation models.Then,the Regional Ocean Modelling Systems is applied to the ECS to evaluate the contributions and relative importance of impacts from the river discharge,wind forcing and open boundary data.Our simulations reproduce the phenomena that more fresh water extends northeastward in 2006 and forms a negative SSS anomaly to the northeast of the river mouth comparing with 1999,which is consistent with observations.The five group numerical tests suggest that the wind forcing dominates the CDW variations followed by the Kuroshio and its branches.
-
Key words:
- Changjiang /
- Changjiang Diluted Water /
- summer /
- variations /
- dynamics /
- hypoxic zone
-
李道季,张经,黄大吉,等.长江口外氧的亏损[J].中国科学(D辑),2002,32(8):686-694. WEI H,HE Y,LIA Q,et al.Summer hypoxia adjacent to the Changjiang Estuary[J].Journal of Marine Systems,2007,67(3/4):292-303. CHEN C C,GONG G C,SHIAH F K.Hypoxia in the East China Sea:one of the largest coastal low-oxygen areas in the world[J].Marine Environmental Research,2007,64(4):399-408. 张莹莹,张经,吴莹,等.长江口溶解氧的分布特征及影响因素研究[J].环境科学,2007,28(8):1649-1654. 邹建军,杨刚,刘季花,等.长江口邻近海域九月溶解氧的分布特征[J].海洋科学进展,2008,26(1);65-73. OFFICER C B,BIGGS R B,TAFT J L,et al.Chesapeake Bay anoxia:origin,development,and significance[J].Science,1984,223 (4631):22-27. KUO A,NEILSON B.Hypoxia and salinity in Virginia estuaries[J].Estuaries and Coasts,1987,10(4),277-283. STANLEY D W,NIXON S W.Stratification and bottom-water hypoxia in the Pamlico River estuary[J].Estuaries,1992,16(3):270-281. PARK K,KUO A Y,NEILSON B J.A numerical model study of hypoxia in the tidal Rappahannock River of Chesapeake Bay[J].Estuarine,Coastal and Shelf Science,1996,42(5):563-581. DIAZ R J.Overview of hypoxia around the world[J].Journal of Environmental Quality,2001,30(2):275——281. RABALAIS N N,TURNER R E,SCAVIA D.Beyond science into policy:Gulf of Mexico hypoxia and the Mississippi River[J].BioScience,2002,52(2):129-142. GRANTHAM B A,CHAN F,NIELSEN K J,et al.Upwelling-driven nearshore hypoxia signals ecosystem and oceanographic changes in the northeast Pacific[J].Nature,2004,429(6993):749-754. YIN K,LIN Z,KE Z.Temporal and spatial distribution of dissolved oxygen in the Pearl River Estuary and adjacent coastal waters[J].Continental Shelf Research,2004,24 (16):1935-1948. 蒲新明,吴玉霖,张永山.长江口区浮游植物营养限制因子的研究:Ⅱ.春季的营养限制情况[J].海洋学报,2001,23(3):57-65. 王保栋,战闰,藏家业.长江口及其邻近海域营养盐的分布特征和输送途径[J].海洋学报,2002,24(1):53-58. 宁修仁,史君贤,蔡昱明,等.长江口和杭州湾海域生物生产力锋面及其生态学效应[J].海洋学报,2004,26(6):96-106. 毛汉礼,甘子钧,蓝淑芳.长江冲淡水及其混合问题的初步探讨[J].海洋与湖沼,1963,5(3):183-206. 浦泳修.夏季长江冲淡水扩展机制的初析[J].东海海洋,1983,1:43-51. BEARDSLEY R C,LIMBURNER R,YU H S,et al.Discharge of the Changjiang (Yangtze River) into the East China Sea[J].Continental Shelf Research,1985,4:57-76. 顾玉荷.长江冲淡水转向原因的探讨[J].海洋与湖沼,1985,16(5):365-362. 王从敏,翁学传.夏季台湾暖流水对长江冲淡水扩展方向的影响——Fuzzy关系方程的一种应用[G]//海洋与湖沼论文集.北京:科学出版社,1986:13-19. 乐肯堂.长江冲淡水路径问题的初步研究:Ⅱ.风场对路径的作用[J].海洋与湖沼,1989,20(2):139-148. 朱建荣,李永平,沈焕庭.夏季风场对长江冲淡水扩展影响的数值模拟[J].海洋与湖沼,1997,28(1):72-79. 朱建荣,周健.夏季苏北沿岸流对长江冲淡水扩展影响的数值模拟[J].华东师范大学学报:自然科学版,1997(2):62-67. 朱建荣.黄海冷水团对长江冲淡水扩展的影响[J].海洋与湖沼,1998,29(4):389-394. 朱建荣,肖成猷,沈焕庭.夏季长江冲淡水扩展的数值模拟[J].海洋学报,1998,20(5):13-22. 朱首贤,朱建荣.M2分潮对夏季长江冲淡水扩展影响的数值研究[J].海洋与湖沼,1999,30(6):711-718. 廖启煜,郭炳火,刘赞沛.夏季长江冲淡水转向机制分析[J].黄渤海海洋,2001,19(3):19-25. 自学志,王凡.夏季长江冲淡水转向机制的数值试验[J].海洋与湖沼,2003,34(6):593-603. 赵保仁.长江冲淡水的转向机制问题[J].海洋学报,1991,13(5):600-610. HAIDVOGEL D B,ARANGO H G,HEDSTROM K,et al.Model evaluation experiments in the North Atlantic Basin:simulations in nonlinear terrain-following coordinates[J].Dynamics of Atmospheres and Oceans,2000,32:239-281. EZER T,ARANGO H G,SHCHEPETKIN A F.Developments in terrain-following ocean models:intercomparisons of numerical aspects[J].Ocean Modelling,2002,6(4):249-267. SHCHEPETKIN A F,MCWILLIAMS J C.A method for computing horizontal pressure-gradient force in an oceanic model with a non-aligned vertical coordinate[J].Journal of Geophysical Research,2003,108(C3):3090. SHCHEPETKIN A F,MCWlLLIAMS J C.The regional oceanic modeling system (ROMS):a split-explicit,free-surface,topography-following-coordinate oceanic model[J].Ocean Modelling,2005,9(4):347-404. SONG Y,HAIDVOGEL D.A semi-implicit ocean circulation model using a generalized topography-following coordinate system[J].Journal of Computational Physics,1994,115(1):228-244. LARGE W G,MCWILLIAMS J C,DONEY S C.Oceanic vertical mixing:a review and a model with a nonlocal boundary layer parameterization[J].Reviews of Geophysics,1994,32(4):363-403. DURSKI S M,GLENN S M,HAIDVOGEL D B.Vertical mixing schemes in the coastal ocean:comparison of the level 2.5 Mellor-Yamada scheme with an enhanced version of the Kprofile parameterization[J].Journal of Geophysical Research,2004,109(C01015):doi: 10.1029/2002JC001702. DASILVA A,YOUNG A C,LEVITUS S.Atlas of Surface Marine Data 1994,volume 1:Algorithms and Procedures[M]//Washington,D.C.:U.S.Department of Commerce,1994:NOAA Atlas NESDIS 6. 陈达熙.渤海、黄海、东海海洋图集——水文[M].北京:海洋出版社,1992:133-144. BLECK R.An oceanic general circulation model framed in hybrid isopycnic-Cartesian coordinates[J].Ocean Modelling,2002,37(4):55-88. FLATHER R A,HEAPS N S.Tidal computation for the Morecambe Bay[J].Geophysical Journal of the Royal Astronomical Society,1975,42(2):489-517. CHEN X Q,ZONG Y Q,ZHANG E F,et al.Human impacts on the Changjiang (Yangtze) River basin,China,with special reference to the impacts on the dry season water discharges into the sea[J].Geomorphology,2001,41:111-123. ZHANG H M,BATES J J,REYNOLDS R W.Assessment of composite global sampling:Sea surface wind speed[J].Geophysical Research Letters,2006,33:L17714. LARGE W G,POND S.Open ocean momentum flux measurements in moderate to strong winds[J].Journal of Physical Oceanography,1981,11(3):324-336.
点击查看大图
计量
- 文章访问数: 1204
- HTML全文浏览量: 4
- PDF下载量: 1127
- 被引次数: 0