The spatial and temporal distribution of pipe formation,offshore Namibia

A group of nearly 400 pipe structures from the continental slope of northern Namibia are analysed for their spatial and temporal distribution. The pipes most likely formed as a result of highly focused fluid venting, and understanding the factors controlling their distribution in space and time is key to their genesis. We analysed their spatio-temporal distribution using an arbitrary chronostratigraphic timescale, from which it is concluded that the pipes did not form at the same time. Pipe formation is shown to be intermittent and persistent, with 2–29 pipes forming in each of the >20 arbitrary time intervals that are considered to span the Neogene period. The spatial distribution of these pipes is clustered to dispersed. Spatial statistics conducted on the distribution of pipe formation timings have shown that two statistically significant groups of pipes exist within the population, (1) in the North and West and (2) in the South, with the former occurring prior to the latter. Locally, pipe formation is sporadic with clusters and outliers occurring during the same time period. A conceptual model is proposed whereby pipe formation in specific locations is the result of localised breaching of the seals for isolated pressure cells which are locally independent yet broadly controlled. An inferred basinal fluid source is thought to determine the broader patterns of pipe formation, and the focus of this fluid source shifts from North to South with time. At a local scale, multiple local factors interact producing a sporadic pipe formation distribution through a prolonged period of highly focused fluid migration. Once formed, the pipes continued to focus fluids intermittently, leading in some cases to later pockmark formation.     

Study on spatial and temporal distribution of planktonic amphipoda in the East China Sea

Quantitative distribution of planktonic amphipoda in the East China Sea is analyzed and the relation with environmental factors and mackerel and scad fishing grounds is studied. The result shows that the characteristic of biomass is great seasonal and interannual variety during the passing three decades. The distribution of planktonic amphipoda basically reflects the movement, decay and intensification of the different water systems in the survey area.     

北部湾海域叶绿素a质量浓度时空分布研究

叶绿素a质量浓度是水体富营养化的重要指标,及时和有效地对水体叶绿素a质量浓度进行监测和评价,对环境保护十分必要。本文基于2011年至2016年的卫星遥感数据,分析了北部湾海表叶绿素a质量浓度的时空分布特征。研究结果表明:北部湾叶绿素a质量浓度有明显的月变化和季节性变化,北部湾叶绿素a月平均质量浓度在8月和1月分别达到峰值,北部湾冬季与夏季的叶绿素a季平均质量浓度高于春季和秋季,夏季北部湾海域表层的叶绿素a质量浓度开始迅速升高,秋季北部湾中南部叶绿素a质量浓度呈下降的趋势。在空间分布上,北部湾近岸海域叶绿素a质量浓度平均水平较高,叶绿素a质量浓度高值区集中在湾北部雷州半岛西部沿岸的浅水区海域,而低值区在湾中部以及湾南部的深水区海域。     

Study on spatial and temporal distribution of planktonic amphipoda in the East China Sea

Quantitative distribution of planktonic amphipoda in the East China Sea is analyzed and the relation with environmental factors and mackerel and scad fishing grounds is studied. The result shows that the characteristic of biomass is great seasonal and interannual variety during the passing three decades. The distribution of planktonic amphipoda basically reflects the movement, decay and intensification of the different water systems in the survey area.     

东海浮游端足类数量的时空分布特征

分析了东海端足类数量分布的时空变化,并就其与环境因素及鲐鯵渔场的关系进行了初步探讨,结果显示本区端足类数量季节变化和年际变化显著,其分布状况与黄海冷水、江浙沿岸流、台湾暖流以及黑潮在本区运动消长有关,与鲐鯵渔场分布有着密切关系.     

北太平洋低纬度西边界流(NMK)的时空特征

利用高分辨率的长时间序列海洋模式资料OFES(OGCM for the Earth Simulator),对北太平洋低纬度西边界流的时空分布特征及其与.ENSO循环的联系进行了初步分析.结果表明:北太平洋低纬度西边界流具有明显的季节和年际变化特征.在季节尺度上,整个NMK系统都表现为春强秋弱,而在年际尺度上,NEC和K...     

Spatial distribution and corresponding determining factors of metal concentrations in surface sediments of Beppu Bay, southwest Japan

This study determined the factors contributing to the spatial distribution of 14 metal concentrations in the surface sediments of Beppu Bay on the basis of comparisons of the organic geochemical properties and environmental parameters through principal component analysis (PCA) and redundancy analysis (RDA). The results of PCA and RDA showed that the concentrations of V, Cr, Co, and As were closely related to the distances between the sampling sites and the Oita River. This indicated that these metals originated from the river's drainage area. The Mn, Cu, Mo, and Cd concentrations were related to the water depth. These results indicated that the Mo, Cd, and Cu deposition processes were controlled by oxygen depletion, and that these elements accumulated in the deeper parts of the bay under anoxic conditions.     

湄洲湾海域甲藻孢囊的时空分布初步调查

为了解湄洲湾海域表层沉积物中甲藻孢囊的时空分布特征,于2018年5月(春)、8月(夏)、11月(秋)和2019年2月(冬)采集湄洲湾海域7个站位表层沉积物样品,进行甲藻孢囊分析,共鉴定出甲藻孢囊6大类42种和2种未知种。异养型甲藻孢囊种类数和丰度均高于自养型甲藻孢囊,其中又以原多甲藻类孢囊的种类和丰度最高。季节间差异不明显：种类数介于34～38种之间,丰度则在397.8～569.5 cysts/g之间变化,全年平均丰度448.0 cysts/g。工业区附近的站位种类数和丰度均低于养殖区附近的站位和对照点。优势种高达16种,原多甲藻类占绝对优势,但全部优势种优势度均不大。多样性指数、丰富度指数和均匀度指数均较高,全年的平均值分别为3.45、1.55和0.92。与历史资料对比,新发现19种孢囊,但丰度相差不大。另需注意的是,在湄洲湾海域共发现6种有毒甲藻孢囊,虽然全年丰度均不高,但仍有暴发有毒赤潮的危险,需引起重视。     

The temporal and spatial distribution of underwater quantum irradiation in a southern California kelp forest

The weekly integrals of underwater photon flux density were measured for a two and a half year period in a southern California kelp forest. Photon flux densities were lowest from January to April and peaked in summer. On average, about 2% of the surface irradiation reached the bottom (depth of 13·2 m in an area without a kelp canopy). Photon flux densities under a canopy of giant kelp were reduced by 70% compared to a nearby site cleared of kelp. A significant portion of temporal variability in underwater photon flux density was explained by vertical sediment flux. Surface irradiation did not contribute significantly to the variance in weekly values of underwater irradiation.     

浙江近岸海域赤潮事件时空分布特征研究

利用浙江省海洋灾害公报中2006-2017年的赤潮灾害数据,分析了浙江近海赤潮的年、月和季节尺度的变化规律,同时分析了浙江近海赤潮的空间分布规律.将自适应带宽核密度分析方法应用于赤潮灾害研究,分析了浙江近海不同海域受赤潮影响的程度.研究结果表明:浙江海域赤潮高发于春末和夏季,5月是发生峰值期;从年际情况看,近年来赤潮发...     

Satellite-derived measurements of spatial and temporal chlorophyll-a variability in Funka Bay, southwestern Hokkaido, Japan

Chlorophyll-a (chl-a) concentration has an important economic effect in coastal and marine environments on fisheries resources and marine aquaculture development. Monthly climatologies the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) derived chl-a from February 1998 to August 2004 around Funka Bay were used to investigate the spatial and temporal variability of chl-a concentrations. SeaWiFS-derived suspended sediment, MODIS derived sea surface temperature (SST), solar radiation and wind data were also analyzed. Results showed two distinct chlorophyll blooms in spring and autumn. Chl-a concentrations were relatively low (<0.3 mg m⁻³) in the bay during summer, with high concentrations occurring along the coast, particularly near Yakumo and Shiraoi. In spring, chl-a concentrations increased, and a large (>2 mg m⁻³) phytoplankton bloom occurred. The spatial and temporal patterns were further confirmed by empirical orthogonal function (EOF) analysis. About 83.94% of the variability could be explained by the first three modes. The first chl-a mode (77.93% of the total variance) explained the general seasonal cycle and quantified interannual variability in the bay. The spring condition was explained by the second mode (3.89% of the total variance), while the third mode (2.12% of the total variance) was associated with autumn condition. Local forcing such as the timing of intrusion of Oyashio water, wind condition and surface heating are the mechanisms that controlled the spatial and temporal variations of chlorophyll concentrations. Moreover, the variation of chlorophyll concentration along the coast seemed to be influenced by suspended sediment caused by resuspension or river discharge.     

南黄海金潮的遥感监测及时空分布特征研究

近年来海洋生态灾害频发,大量漂浮藻类聚集在海面和近岸海域,给沿岸城市的经济活动和生态健康带来了严重危害。本研究利用HY-1C、GF-1和HJ-1A/1B卫星遥感影像对南黄海海域2016–2020年4–6月份的马尾藻进行了信息提取和生长阶段的划分,并通过MODIS海温数据、光合有效辐射数据和海面风场数据来探究环境因子对马尾藻时空分布的影响。结果表明：（1）从时间上看马尾藻集中在每年的4–6月份暴发,2017年马尾藻的影响范围最大,其余年份较小;从空间上看马尾藻最早在长江入海口东北部远海被监测到,在35°～36°N附近海域消失;（2）从生长速率上看,马尾藻的生长阶段可以划分为“发展–暴发–消亡”3个阶段;（3）在不同的生长阶段,海水温度和光合有效辐射对马尾藻具有不同程度的影响,较高的海表温度和光合有效辐射导致2017年面积高于往年;在东南风的作用下,马尾藻呈从东南向西北漂移的趋势,这说明了马尾藻的时空特征受到多种环境因子的影响。     

台湾海峡及其邻近海域灾害性海浪的时空分布

据１９６６～１９９３年台湾海峡及其邻近海域灾害性海浪观测资料的统计分析得出,东海灾害性海浪平均每年出现１１．４６次,台湾海峡为７．２９次,台湾以东洋面及巴士海峡为１０．１１次;该区灾害性海浪出现次数有显著的年际和月际变化。这些结果可为台湾海峡区域海洋学的发展提供有意义的素材,也为防灾减灾,做好灾害性海浪短期预报和中、长期预测提供一条有效途径。     

浙江沿海台风风暴潮时空分布特征分析

本文通过对1950～2009年60年间270次台风风暴潮过程中最高潮位和最大增水数据进行统计和分析,得到了浙江沿海地区风暴潮增水和高潮位的时空分布特征。     

Summarising spatial and temporal information in CPR data

The Continuous Plankton Recorder survey provides pan-oceanic data on geographic distribution, species composition, seasonal cycles of abundance, and long-term change during the last 70 years. In this paper we compare and contrast some of the historic data-analytic protocols of the survey, focusing primarily on the various means by which spatio-temporal information in CPR data has been exposed. Relative strengths and limitations are assessed, followed by suggestions for future approaches to the visualisation and summarising of CPR data.     

Horizontal spatial and temporal distribution patterns of nearshore larval fish assemblages at a temperate rocky shore

There have been no previous studies of the composition of nearshore larval fish assemblages along the coast of Portugal. We aimed to describe the composition and horizontal distribution patterns of larval fish assemblages and their temporal dynamics near a rocky reef at depths shallower than 13 m (inshore) and at two miles (3.70 km) from shore (offshore), as well as along transects perpendicular to the shoreline, from the reef to 10 miles offshore (18.52 km). Samples were taken using 5 min sub-surface trawls at the rocky shore of the Arrábida Marine Park (W Portugal). A total of 1021 larvae were collected, belonging to 61 taxa inshore and to 29 taxa offshore. Along transects, 626 larvae of 52 taxa were collected. Most larvae belonged to coastal species associated with rocky reefs. Total larval abundance and diversity were higher from May to July, which is consistent with the spawning activity of adults. Diversity and total larval abundance decreased significantly with increasing distance from shore, both in the inshore/offshore comparison and in the transects, where this decrease was evident at a very small spatial scale (within the first mile from the reef). Species assemblages differed in the pattern of distribution, with most species clearly associated to the extreme nearshore. The distribution patterns obtained were independent of the spawning mode of species. Results are discussed in the light of the possible physical mechanisms that can potentially act at the Arrábida Marine Park to facilitate larvae retention and the role of larval behaviour.     

长江口水体表层悬浮泥沙时空分布对环境演变的响应

基于1974-2009年15个时相的陆地卫星影像,采用Gordon模型在长江口地区开展了悬浮泥沙浓度反演研究。对反演结果的时空分布规律分析表明:近40 a来长江口悬浮泥沙浓度最大下降幅度达40%;悬浮泥沙浓度演化规律与长江口来沙量变化规律具有较好的相关性;曲线拐点与2003年的长江截流、2006年三峡水库蓄水等重大工程事件吻合良好。在忽略波浪、地形等影响因素的情况下,在长时间跨度范围内,遥感技术反演的长江口悬浮泥沙浓度对长江流域环境变迁与人类水利工程活动响应敏感,较好的揭示了环境的变迁。     

0414号“云娜”台风浪时空分布特征的遥感研究

综合利用GFO、TOPEX/Poseidon、Jason-1和Envisat等4颗卫星高度计的有效波高数据以及QuickSCAT散射计的风场数据,分析了0414号"云娜"(RANANIM)台风浪的时空分布特征以及浪场和风场之间的相互关系.结果表明:(1) 台风浪融合结果图较好地显示了台风的移动路径,该路径与美国NASA提供的台风路径基本一致;(2) 随着时间的推移,"云娜"由热带风暴逐渐演变成强台风,它所生成的台风浪也越来越大,平均浪高由最初的5.5 m左右增至8.5 m左右,最大浪高从6.5 m增加到10.6 m;(3) 台风浪中心与台风中心的空间分布基本一致,台风浪相对于台风中心近似成对称(圆形)分布,其影响半径大概为400～500 km;(4) 结合由QuikSCAT散射计提供的风场数据可以发现,台风中心风速从20 m/s左右逐渐发展到30 m/s以上,海面对应的日平均浪高也由4～5 m发展到6.5～8.5 m,台风影响下出现的15 m/s以上风速的径向半径和分布范围与3 m以上浪高的径向半径和分布范围基本一致.     

山东气溶胶光学厚度时空分布及其与地面大气污染物质量浓度的相关性分析

基于卫星的气溶胶光学厚度(aerosol optical thickness,AOT)是研究大气污染程度及时空变化的重要参考,由于大气污染物排放特征、地理和气候背景不同,不同区域AOT的时空分布及其与地面大气污染物质量浓度的相关性存在一定的差异.选取了2017年7月-2020年7月山东89个国家环境空气质量监测站数据、...