北赤道流分叉点及南海北部环流的研究进展

介绍了北赤道流分叉点、南海北部环流的一些研究成果,并就黑潮对南海的影响所作的研究进行了回顾.北赤道流分叉点的位置对于北赤道流系水体疏运变化及在黑潮和MC之间水体、热量、盐度输运的分配中起着重要的作用.北赤道流分叉点位置约在14.6°N上,分叉点位置随深度增加而北移.分叉点有明显的季节变化和年际变化,在春、夏季向南移动,而在秋、冬季则向北移动.年际变化与ENSO现象相关紧密,在El Nio事件NEC分叉纬度处于最北端,在La Nio事件处于最南端.对于分叉点位置的定量化研究,仍然需要更多的观测结果进行研究.季风和黑潮是影响南海北部环流的两种主要因素.南海北部上层流场主要由广东沿岸流、黑潮入侵流套、东沙海流、南海暖流和吕宋海流组成.除海盆、次海盆尺度环流外,受季风、黑潮和地形等因素的影响,南海表现出多涡结构.通过近些年的卫星观测和数值模拟的结果,人们对南海中尺度涡的认识大大加深,但要想模拟出风应力形成涡的机制,还需要提高风场和模式的分辨率.由于观测资料的限制,对南海流场的垂直结构、以及春-秋季季风转相时期的流场结构等还研究得较少.吕宋海峡水交换是西太平洋对南海影响的主要途径.黑潮在吕宋海峡附近的形变一直是有争议的热点问题,目前对于黑潮入侵有3种观点:(1) 认为黑潮经过吕宋海峡形成流套结构,并分离出中尺度涡影响南海流场、水团结构;(2) 认为黑潮有一直接分支分离出来进入南海形成黑潮分支;(3) 认为吕宋海峡水交换不属于以上两种情况,西太平洋对南海的水团输送另有机制.北赤道流分叉点在对黑潮的水体、热量、盐度输运的分配中起着重要的作用,黑潮对南海北部环流的影响可能与NEC的分叉点位置有关,但目前对NEC的分叉点位置与南海北部环流相关性的研究甚少.最后提出了对未来加强该方面研究的一些展望.     

Identification of CO2 disposal locations in an ocean general circulation model of the North Pacific

A basinwide ocean general circulation model of the North Pacific is used to identify which location is more efficient for ocean CO2 sequestration in the North Pacific. Four injection depths at each one of fifteen locations are chosen. In terms of effectiveness index (EI) and escape factor (EF), it is clear that the effectiveness increases with increasing latitude at the end of the 50 a injection period. Sitebysite differences in the EI can be over 9% for the 1 000 m injection depth in the western North Pacific at the end of 50 a of continuous injection. The difference is much larger for the 500 m injection. The difference decreases with increasing injection depth. However, the sitebysite difference is small for the injection in the eastern North Pacific. The sequestration is more efficient for the injection in the east than in the west. For the 500 m injection depth, the difference in effectiveness between the west and the east is over 10% at the end of 50 a injection period. The largest concentration of sequestered CO2 increases with increasing injection depth. For the injection in both the western and central North Pacific, the largest exchange flux always appears to be at about 42°N, 150°E, whereas for the injection in the eastern area the large flux appears to be in the equatorial region (120°W).     

运用荧光显微技术分析北黄海夏季浮游病毒的分布

运用荧光显微技术(Epifluorescence Microscopy,EFM),对2006年夏季北黄海水域31个站点的病毒丰度进行了检测,对浮游病毒丰度在水平分布,垂直分布和昼夜变化上进行了探讨.北黄海水域浮游病毒直接检测量(Virus Direct Count,VDC)为(1.58×106～1.38×107)/mL,平均为5.86×106/mL.在水平分布上,表层、30 m和底层水在辽东半岛头部附近出现了病毒较高区域,近海水域的病毒丰度较中部水域高(P＜0.05).在垂直分布上,表层浮游病毒丰度高于30 m水层和底层(P＜0.05).在昼夜变化上,表层水体中浮游病毒量有明显的变化,10 m水层和30 m水层的病毒丰度昼夜变化较明显,底层病毒丰度昼夜趋势平缓.利用多元相关分析可知,北黄海夏季浮游病毒丰度与站位总水深(P＜0.01)和盐度(P＜0.05)成一定的负相关性,与温度无明显相关性(P＞0.05).     

冬季北黄海表层海水pCO_2分布及其影响因素探讨

根据2006年12月在北黄海走航连续观测所得pCO2 数据,结合水文、化学和生物等要素的同步观测资料,对该海域pCO2分布及其影响因素进行了探讨.结果表明:冬季北黄海表层海水pCO2测值在203～683 μatm之间,平均值为408 μatm.辽南沿岸流及其影响区域是大气CO2汇区;山东半岛以北沿岸,122°E以西受渤海环流输送,黄河悬浮颗粒物影响的高浑浊度区域是大气CO2的一个强源区(最高值达到683 μatm);而占据北黄海大部的黄海混合水以及北黄海整体上是大气CO2的弱源.冬季北黄海表层海水pCO2分布主要受控于海水温度、碳酸盐体系平衡和生物活动,即温度越高pCO2越高、DIC 越高pCO2越高、叶绿素含量越高pCO2越低.其中辽南沿岸流及其影响区域生物活动的影响最为显著.而山东半岛以北沿岸的高浑浊度区域水体性质具有特殊性,较高的 pCO2受控于高的DIC浓度以及陆岸的影响.     

Modeling Arctic Ocean heat transport and warming episodes in the 20th century caused by the intruding Atlantic Water

This study investigates the Arctic Ocean warming episodes in the 20th century using both a high-resolution coupled global climate model and historical observations. The model, with no flux adjustment, reproduces well the Atlantic Water core temperature （AWCT） in the Arctic Ocean and shows that four largest decadalscale warming episodes occurred in the 1930s, 70s, 80s, and 90s, in agreement with the hydrographic observational data. The difference is that there was no pre-warming prior to the 1930s episode, while there were two pre-warming episodes in the 1970s and 80s prior to the 1990s, leading the 1990s into the largest and prolonged warming in the 20th century. Over the last century, the simulated heat transport via Fram Strait and the Barents Sea was estimated to be, on average, 31.32 TW and 14.82 TW, respectively, while the Bering Strait also provides 15.94 TW heat into the west- ern Arctic Ocean. Heat transport into the Arctic Ocean by the Atlantic Water via Fram Strait and the Barents Sea correlates significantly with AWCT （ C = 0.75 ） at 0- lag. The modeled North Atlantic Oscillation （NAO） index has a significant correlation with the heat transport （ C = 0.37 ）. The observed AWCT has a significant correlation with both the modeled AWCT （ C =0.49） and the heat transport （ C =0.41 ）. However, the modeled NAO index does not significantly correlate with either the observed AWCT （ C = 0.03 ） or modeled AWCT （ C = 0.16 ） at a zero-lag, indicating that the Arctic climate system is far more complex than expected.     

Results of recent Pacific-Arctic ice-ocean modeling studies at the Naval Postgraduate School

Summary of results from a high - resolution pan - Arctic ice - ocean model are presented for the northern North Pacific, Bering, Chukchi, and Beaufort seas. The main focus is on the mean circulation, communication from the Gulf of Alaska across the Bering Sea into the western Arctic Ocean and on mesoscale eddy activity within several important ecosystems. Model results from 1979 -2004 are compared to observations whenever possible. The high spatial model resolution at 1/12o （or -9 - km） in the horizontal and 45 levels in the vertical direction allows for representation of eddies with diameters as small as 36 km. However, we believe that upcoming new model integrations at even higher resolution will allow us to resolve even smaller eddies. This is especially important at the highest latitudes where the Rossby radius of deformation is as small as 10 km or less.     

西藏羌北布若错晚白垩世中酸性侵入岩特征及地质意义

羌北布若错中酸性侵入体,以浅成—超浅成相的花岗斑岩、流纹质碎斑熔岩为主,另有少量花岗闪长斑岩、英安质碎斑熔岩。用K_2O—SiO_2亚碱性岩分类图解、球粒陨石标准化稀土元素配分型式、C/MA和A/FM摩尔比值图解等分析方法,该岩体岩石显示出富含K、Rb、Th及REE,具中等—强的Eu亏损及强过铝质的特点,反映了岩浆源主要来自于上地壳的部分熔融,具有S型花岗岩的特征。在碎斑熔岩中获得全岩K—Ar法同位素年龄为94.8Ma,反映该岩体侵入时代为晚白垩世。     

北黄海盆地北缘断裂带及其特征

根据最新调查获得的北黄海盆地海洋重力、海洋与航空磁力和多道地震资料,结合以往周边地区的资料,编制了北黄海空间重力异常图、布格重力异常图、磁力异常图。在重磁基础图件的基础上,通过解析延拓、任意方向导数计算、离散小波变换等处理,结合地震和地质资料,对北黄海北缘断裂带进行了综合分析。确定了北黄海北缘断裂带的存在,并对该断裂带的延伸长度、切割深度和性质进行了分析,指出北黄海北缘断裂带是辽东隆起与北黄海盆地的界线,断裂带两侧具有明显不同的地球物理场特征;而且断裂带具有多期活动的特点,对北黄海盆地的形成演化具有重要的控制作用。     

北黄海盆地地质构造特征及其在油气勘探中的意义

通过对近年来在北黄海盆地的油气勘探认识的总结,结合区域地质研究成果,从盆地的基底结构、地质结构和主要构造类型等方面对北黄海盆地的地质构造特征进行了分析。提出北黄海盆地是在前中生代结晶基底之上发展起来的,盆地经历了走滑拉分(J3-K1)、断陷(E2-E3)、拗陷(N—Q)3次主要的沉降作用过程,形成了下、中、上3个构造层,在盆地内发育了断裂、褶皱和潜山3种基本构造类型。盆地的这种构造特征为盆地内油气的生成运聚提供了物质基础和边界条件,特别是晚侏罗世—早白垩世由于走滑拉分形成的下构造层具有较好的生烃物质基础,同时还有良好的圈闭发育条件,后期的构造改造也有利于油气的生成聚集,应是北黄海盆地的主要勘探对象。     

北黄海潮流、余流垂直结构及其季节变化

基于对2006年夏季与2007年冬季在123.51°E,38.00°N的各1个月潮流和水位观测数据的分析,发现夏季余流呈现两层结构,上层流向为西北,下层流向东南,并且当大潮日期附近,在跃层附近深度存在若干流速较强的水层;冬季余流除了个别层以外基本上均为西北向流入北黄海,从中可以看到风场改变所引发的异常增减水和强流出现。对潮流椭圆的分析表明,半日潮族分潮流的最大流向自夏季至冬季存在着顺时针的旋转,旋转角大约为16(°)～18(°),并且夏季半日潮族随深度顺时针,全日潮族逆时针旋转,而冬季基本上上下一致。