人工神经网络在潮汐数值预报中的应用

潮汐数值预报经过了几十年的发展,但是其预报精度并不能让人十分满意,本文试图将传统的潮汐数值预报模式与近年来发展迅速的人工神经网络相结合并改进潮汐数值预报的精度。文章建立了一个神经网络系统,采用潮汐数值模式的输出结果作为网络输入,潮位观测资料作为输出,用建立的神经网络进行训练,结果表明人工神经网络可以明显地改进潮汐数值预报的精度。     

辽东湾觉华岛附近海域海底地形地貌及沉积物分布特征分析

为对辽东湾觉华岛附近海域海底工程地质环境进行系统评估,利用高分辨海底声学探测设备获取调查海区的精密水深地形及浅地层剖面数据,利用筛析法、激光粒度仪实验法确定表层沉积物类型及粒度参数特征,综合分析了研究区海底地形地貌及沉积物分布特征.研究发现,目标海域测量水深介于4～22 m之间,平均水深15 m左右,海底地形平坦,整体...     

Influence of reclamation works on the marine environment in a semi-enclosed bay

1Introduction GamakBay,anegg shapedseasurfaceareaofap proximately112km2,isasemi enclosedshallowwaterareawithameandepthof9mandhasbotheastandsouthchannelstoreceiveseawaterfromoutside(seeFig.1).Similarscalesoftidalwavesalmostsimultane ouslyenterorexitthrough…     

豫西荥巩——新密煤田太原组、山西组的沉积环境和聚煤规律

荥巩和新密煤田是豫西北部的两个相邻煤田。主要含煤地层为晚古生代晚石炭世太原组和早二叠世山西组,总厚100—150m;下石盒子组及晚二叠世的上石盒子组在本区仅偶含薄煤层。太原组位于含煤岩系最底部,为碳酸盐岩和碎屑岩交替沉积,灰岩形成于清澈、温暖、浅水的陆表海潮下环境,碎屑岩则为潮道和潮间带为主的潮道、潮坪沉积。太原组含有6—7层薄煤层,形成于咸水或半咸水的泥炭沼泽中。山西组几乎全由碎屑岩组成,下部发育本区的主要可采煤层二1煤。二1煤以下层位为潮坪和横向与之共生的潮道、潮沟及河口潮汐砂脊沉积,二1煤以上为河流作用为主的三角洲沉积,三角洲由北向南进积到半咸水的海湾中。二1煤形成于海退时期,它们堆积在滨海平原的淡水泥炭沼泽中,其厚度变化及发育程度主要受成煤前沉积环境控制,但在本区西部构造较复杂处,煤层厚度受后期构造影响较大。沉积环境对煤层原生厚度的影响主要表现在潮坪和废弃的潮道、潮沟、河口潮汐砂背沉积物之上,煤层发育好,而在二1煤之下有活动的潮道及河口潮汐砂脊发育时,煤层较薄或不发育。     

杭州湾南岸庵东潮坪现代沉积特征

在进行庵东潮坪水文要素定点测量的基础上,对地貌特征,沉积粒度,沉积构造及重向剖面作了全面分析与研究。结果表明,滩地位于杭州湾进、退潮流的交会点,控制其发育的主动力为潮汐作用,具明显的不规则半日潮特性,涨潮流强度远大于落潮流,造就了宽达十余公里的潮滩地貌。滩地水动力深受湾内水流影响,高潮期服从其总体潮流流向,导致潮坪上发育众多与杭州湾深槽系统相连的潮沟,破坏了沉积物正常分布规律,高潮坪存在一定向平行岸线的大型潮沟,受强劲水流影响,沉积粒度粗化,并因快冲快淤而产生变形构造;中潮坪接受退潮期潮沟漫岸物质,粒度相对较小,分选性变差,沉积构造以直脊流水波痕及板状交错层理为主;低潮坪潮流作用大、沉积粒度粗,分选性最佳,发育小型流水波痕,内部构造以槽状交错层理,“青鱼刺”层理及再作用构造为特征。潮坪近岸处潮沟迁移层序及浪成波痕层理的发现反映水动力异常强大,威胁人工海塘的安全,建议停止进一步围垦滩涂,采取促淤方法,抑制潮沟的发育,以维持滩地稳定。     

胶州湾东北部营养盐的季节和多年变化

根据1991-2004年的调查资料,探讨了胶州湾东北部水域营养盐及其摩尔比的月、旬的变化和多年变化以及与年、Chla的关系.月和旬的变化表明春、夏季,各种营养盐浓度以锯齿状的形式呈缓慢上升趋势,与外源性营养盐增加密切相关,只有SiO₃-Si在8月份出现明显峰值,SiO₃-Si/DIN和SiO₃-Si/PO₄-P比也有相似的变化;秋季以后营养盐浓度急剧增加,特别是SiO₃-Si和DIN,导致了冬季赤潮的爆发.在赤潮高峰时,营养盐大量消耗,特别是SiO₃-Si几乎耗尽(0.49μmol/L),SiO₃-Si/DIN和SiO₃-Si/PO₄-P比迅速下降(分别为0.01和1.04),SiO₃-Si成为浮游植物生长的限制因子,控制了赤潮的进一发展,并初步讨论了赤潮发生的化学海洋学机制.营养盐的季节变化与Chla含量呈明显的消长关系.营养盐及其结构的多年变化表明,1999年以后比1991-1998年DIN和SiO₃-Si的平均浓度分别增加了1.0和2.2倍,DIN/PO₄-P比和SiO₃-Si/PO₄-P比分别增加了0.4和0.9倍,PO₄-P、SiO₃-Si/DIN比略有增加,营养盐之间的摩尔比都偏离了Redfield比,这与青岛市社会经济发展密切相关.     

Coastline and landscape changes in bay areas caused by human activities: A comparative analysis of Xiangshan Bay,China and Tampa Bay,USA

Using multitemporal Landsat TM/OLI images at a 10-year interval, in this study, we (1) extracted information of spatial location, length, and sinuosity of coastline and landscape configuration, diversity and fragmentation in the bay areas of Xiangshan Bay (XB), China and Tampa Bay (TB), USA from 1985 to 2015; (2) constructed indices of artificial coastlines and human disturbance on bay area landscapes; and (3) explored and discussed the impacts of human activities on changes of coastlines and landscape types in the two bay areas. Our analysis results demonstrate the following five points. (1) During the past 30 years, the lengths of natural coastline in XB and TB shrank, while the lengths of their artificial coastline increased first and then maintained stable. Since there were different influences of human activities on coastlines and landscape types between the two bay areas, XB experienced dramatic changes in parts of coastline geomorphologies and continuous decrease of coastline sinuosity, while, in TB, there was a little change in coastline geomorphologies and its coastline sinuosity was almost unchanged. (2) The intensity of human activities in XB was continuously enhanced from 1985 to 1995, and then the degree of enhancement had slowed down after 1995. However, in the time period, the impacted extent of human activities gradually increased and finally covered almost entire coastlines in XB. In TB area, although the intensity of human activities was enhanced, the degree of enhancement slowed down from 1985 to 2015 and the impacted areas of human activates were concentrated in several coastal city areas. (3) The average area of landscape patches strongly disturbed by human activities in both XB and TB generally showed a trend of decreasing from 1985 to 2005. However, during the period of 2005 to 2015, the average patch area of landscapes disturbed by different degrees of human activities in XB changed differently, while in TB it almost did not change. (4) From 1985 to 2005, the indices of landscape diversity in various areas of human disturbance in XB gradually increased, while in TB, changes in indices of the landscape diversity varied. From 2005 to 2015, the changes in the intensity of human disturbance in both bay areas were from weak to strong, whereas the indices of landscape diversity in XB and TB increased first and then decreased. (5) The landscape fragmentation index in different human disturbance areas in both XB and TB gradually increased from 1985 to 2005, while from 2005 to 2015, in both bay areas, the landscape fragmentation index presented a decreasing trend.     

人类活动对港湾岸线及景观变迁影响的比较研究————以中国象山港与美国坦帕湾为例

利用多时期遥感数据,以10年为时间步长,提取1985-2015年4个时期中国象山港和美国坦帕湾的岸线空间位置,长度和曲折度以及港湾地区景观构型,多样性和破碎度等信息,构建海岸人工化和港湾景观人工干扰指标,探讨人类活动对港湾岸线,景观演变的影响.结果表明:① 近30年来,象山港和坦帕湾自然岸线长度不断缩减,人工岸线长度呈先增后稳定的态势.由于两地人类活动方式的差异,象山港局部岸段形态发生剧烈变化,岸线曲折度不断变小;而坦帕湾岸线形态变化较小,岸线曲折度几乎保持不变.② 1985-1995年,象山港海岸人工化不断加强,1995年以后有所减弱,但人类活动的影响范围逐渐变大,几乎遍及整个港湾海岸.1985-2015年,坦帕湾海岸人工化强度虽有加强,但增幅缓慢,海岸人类活动也主要集中于各沿海城市区域.③ 1985-2005年,象山港和坦帕湾各人工化强度等级样区景观平均斑块面积总体呈减少趋势,但2005-2015年,象山港各强度样区景观平均斑块面积变化趋势不一,坦帕湾各强度样区变幅则较为平稳.④ 1985-2005年,象山港各强度样区景观多样性指数逐渐增大,而坦帕湾变化不一;2005-2015年,两港湾人工化强度由弱至强,景观多样性指数先增后减.⑤ 1985-2005年,象山港和坦帕湾不同人工化强度样区,景观破碎度指数逐渐增大;2005-2015年,两港湾景观破碎度指数呈减小趋势.