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1.
卫星遥感速报北太平洋渔场海温方法研究   总被引:6,自引:1,他引:6       下载免费PDF全文
渔场海温速报是开展渔情分析和确定中心渔场的基础,卫星遥感技术可以快速提供大面积海洋环境参数分布图,由于大洋渔场超出了陆基卫星地面站的接收范围,发展船载遥感系统是提供远洋渔场海洋环境条件的有效途径。本研究介绍基于船载的北太平洋渔场海温速报系统、海表温度遥感反演算法和渔场海温速报产品制作等内容。海温精度分析结果表明,卫星遥感海表温度与船测温度具有良好的一致性,周平均偏差小于0.01℃,RMS平均值为0.7967℃。系统已业务试运行2年,完成北太平洋渔场海温速报产品制作33期,取得了预期目标。  相似文献   

2.
叶绿素a是反映水生态环境污染状况的重要指标。定量反演叶绿素a浓度有助于及时监测水体营养状态变化,对富营养化水体治理具有重要意义。以巢湖及南淝河支流下游为研究区域,利用Sentinel-2卫星遥感数据源,构建其叶绿素a浓度反演模型,探究叶绿素a浓度的时空变化规律。结果显示,构建的深度神经网络(DNN)模型反演精度较高(R2=0.96,MRE=31.62%,RMSE=24.4 μg/L)。通过减少训练样本量对DNN模型精度的影响分析,发现训练样本较少时,模型仍具有较高的精度;根据其精度的敏感模型训练样本个数,将训练集按组等分,模型呈现较好的稳定性并具有一定的适用性。分析表明,研究区叶绿素a浓度在时间上呈现夏秋季上升、春冬季下降的规律,在空间上呈现湖区西高东低、局部近岸区分布较高的特点。  相似文献   

3.
北太平洋公海秋刀鱼渔场初步分析   总被引:4,自引:1,他引:4  
根据2004年7~11月“中远渔1号”调查船北太平洋公海秋刀鱼渔场探捕调查的生产情况,对秋刀鱼渔场进行分析。结果发现:①秋刀鱼渔场可根据渔场位置分为北部渔场和南部渔场,北部渔场范围为44°~45°N、156°~158°E,南部渔场范围为41°~42°N、150°~151°E,南部渔场的分布范围小于北部渔场。②秋刀鱼的生产以11月份生产最好,平均日产量达22.7t,其中最高日产量为60.42t;8月份的秋刀鱼生产最差,平均日产量为2.95t,与2003年的12.05t反差较大,主要是由于受到渔场环境因子变化的影响,鱼发位置偏至俄罗斯专属经济区内的缘故。③秋刀鱼舷提网作业平均日放网次数达7.6次,最高1天放网次数达到16次,而最高网次产量为11.05t。④秋刀鱼渔获组成以中小型鱼为主,占80%以上,除7月份渔获中特大型秋刀鱼占有较大比例外,其余月份很少有特大级秋刀鱼。⑤在相近的渔场位置,秋刀鱼个体随着生产月份的推迟,鱼体呈变小的趋势。  相似文献   

4.
北太平洋柔鱼渔场的环境特征   总被引:12,自引:1,他引:12  
采用棋盘式定点大面调查和中心渔场专项调查2种方式,于2001年5~8月对北太平洋柔鱼(Ommastrephesbartrami)渔场进行了渔业资源与渔场环境特征调查。调查范围为北太平洋152°00′E~171°00′W、39°00′N~43°00′N海域,渔场环境特征要素主要为各站点的温度、盐度、浮游植物、浮游动物和叶绿素a含量。调查海域的柔鱼资源密度采用渔场海域每个经纬度的单位捕捞力量渔获量表示。结果显示,北太平洋柔鱼中心渔场中部与西经渔场表温为18℃左右,100m水温为9℃左右;西部渔场表温为16~20℃,100m水温为7~8℃;在有温跃层海域的跃层面下易形成高产渔场。浮游动物生物量较高的海域与中心渔场的位置基本保持一致;浮游植物生物量较高的海域和叶绿素a含量高于0.1mg/m3的海域,以及它们东侧海域易形成高产渔场;盐度与中心渔场的关系不明显。  相似文献   

5.
6.
l序言剑尖枪乌贼(Omnastrephesbartrami)从副热带至副极地海域,分布范围极广。个体重超过5kg,属大型鱿种。1978年~1992年大规模流网在北太平洋公海上作业。1992年末.流网作业因无针对性而破坏了其它资源、受到国际性的批评,从而由联合国作出限期禁止流网作业的决定。为此,从1992年开始、日本水产厅正式进行鱿钓作业的渔场调查并研究替代流网作业的渔法。本文就枪乌贼鱿鱼渔业的历史及其生态介绍其渔场的形成。2枪乌贼渔业概况70年代,日本周边太平洋柔鱼产量剧减.1973年开始在三陆、道东沿海进行枪乌贼钓捕作业.1977年达到12万吨…  相似文献   

7.
为了解长江口的水质状况,现场测量叶绿素a浓度,结合高光谱遥感影像,运用波段比值模型、一阶微分模型和水体叶绿素a提取指数(Water Chlorophyll-a Index,WCI)对整个研究区域叶绿素a浓度进行反演推算,并进行空间分布评价;利用实测数据和遥感影像的关系建立反演模型,并结合相关系数、均方根误差和平均相对误差,分析和评价反演效果。结果显示,波段比值模型和叶绿素a浓度的相关性达到0.9099,均方根误差为1.7922,平均相对误差为9.09%;一阶微分模型的相关性为0.9483,均方根误差为2.2073,平均相对误差为15.31%;WCI模型的相关性高达0.9778,均方根误差为1.4405,平均相对误差为6.20%。利用WCI模型对整个研究区域的叶绿素a浓度进行模拟,可见研究区域的中间部分叶绿素a含量较低,从中间到两边逐渐增大,南部出现最大值,造成此差异的原因可能是因为北靠近居民生活区,南邻上海青草沙水库,并且附近存在植被。研究表明,WCI模型的反演效果优于波段比值模型和一阶微分模型,是一种计算简单、精度较高的方法,可以有效地提取水体叶绿素a的浓度,未来可广泛应用于水体环境质量监测。  相似文献   

8.
陈庆新  贾复 《水产科学》1999,18(3):44-45
根据作业于北太平洋的鱿鱼钓船的产量数据,经过分析后指出,对于在北太平洋作业的鱿鱼多谢为说,手钓具有举足轻重的地位,机钓与手是相辅助订成,缺一不可的,应该通过经济论证来最后确定最佳船长,合理搭配机钓和手钓,使鱿鱼钓船获得最佳的经济效益。  相似文献   

9.
由于具有明显的时间与空间分辫率优势,遥感方法成为近岸Ⅱ类水体叶绿素浓度(Chl-a)信息提取研究的重要技术之一。本文回顾了国内外叶绿素浓度遥感反演算法研究概况,分析其优缺点,并介绍了利用卫星光学遥感数据反演叶绿素浓度的算法研究成果。并提出加强地面水文光谱实验研究,建立多光谱叶绿素反演定量模式,以高分辫率和高光谱遥感融合数据为基础的叶绿素浓度定量遥感是今后的发展趋势。  相似文献   

10.
北太平洋柔鱼渔场浮游动物数量分布及与渔场的关系   总被引:12,自引:1,他引:12  
徐兆礼 《水产学报》2004,28(5):515-521
根据2001年6-7月在北太平洋152°E~171°W、39°~42°N水域生态环境和资源综合调查资料,分析结果表明调查水域浮游动物总生物量均值为92.12mg·m-3(0.81~1035.68 mg·m-3),其中中部(160°~180°E、39°~42°N)及西经水域(170°~178°W、40°~41°N)为113.51mg·m-3,西部水域(152°~157°E、41°~43°N)为22.89mg·m-3;桡足类丰度居首(42.11%),其次为海樽类(30.91%);伪细真哲水蚤(Eucalanus pseudattenuatus)、太平洋哲水蚤(Calanus pacifica)和软拟海樽(Dolioletta gegenbauri)为主要优势种.甲壳类的分布与柔鱼中心渔场存在较好的对应关系,中心渔场位于浮游动物总生物量高密集区(250~500mg·m-3)和甲壳类的最高丰度区(50~100 ind·m-3)内或边缘区;头足类幼体分布于磷虾类和端足类的高丰度区(10~25ind·m-3)内或边缘水域.  相似文献   

11.
卫星测高数据在渔情分析中的应用探索   总被引:15,自引:0,他引:15  
通过对卫星测高数据的分析,结合日本和美国在海面高度与渔场关系方面的研究,根据海洋学和渔业资源学的理论进行分析和探讨,为卫星测高数据在渔情分析中的应用提供了理论依据、研究思路和基本方法。卫星测高数据与常规海洋外界环境因子有非常密切的关系,经过严格的数据质量控制后,可以应用到渔场探测和渔业资源评估中。测高数据的具体可以采用直接与间接两种方式:直接方式,即作为统计相关的参数,等同于温度、盐度、水色等;间接方式,即作为数理模型的输入或者控制参数。此外,利用卫星测高数据对渔业资源进行中长期评估也具有很好的研究前景。  相似文献   

12.
Skipjack tuna habitat in the western North Pacific was studied from satellite remotely sensed environment and catch data, using generalized additive models and geographic information systems. Weekly resolved remotely sensed sea surface temperature, surface chlorophyll, sea surface height anomalies and eddy kinetic energy data were used for the year 2004. Fifteen generalized additive models were constructed with skipjack catch per unit effort as a response variable, and sea surface temperature, sea surface height anomalies and eddy kinetic energy as model covariates to assess the effect of environment on catch per unit effort (skipjack tuna abundance). Model selection was based on significance of model terms, reduction in Akaike’s Information Criterion, and increase in cumulative deviance explained. The model selected was used to predict skipjack tuna catch per unit effort using monthly resolved environmental data for assessing model performance and to visualize the basin scale distribution of skipjack tuna habitat. Predicted values were validated using a linear model. Based on the four‐parameter model, skipjack tuna habitat selection was significantly (P < 0.01) influenced by sea surface temperatures ranging from 20.5 to 26°C, relatively oligotrophic waters (surface chlorophyll 0.08–0.18, 0.22–0.27 and 0.3–0.37 mg m?3), zero to positive anomalies (surface height anomalies 0–50 cm), and low to moderate eddy kinetic energy (0–200 and 700–2500 cm2 s–2). Predicted catch per unit effort showed a trend consistent with the north–south migration of skipjack tuna. Validation of predicted catch per unit effort with that observed, pooled monthly, was significant (P < 0.01, r2 = 0.64). Sea surface temperature explained the highest deviance in generalized additive models and was therefore considered the best habitat predictor.  相似文献   

13.
Donax trunculus is a much‐appreciated commercial clam whose natural populations have been overexploited in southern–western Spain during the last decades. In order to control the decrease of natural beds, local governments establish annual closed seasons based on socioeconomic reasons, such as economic necessity or tourism interest. The objective of this study was to develop an efficient tool for predicting gonadal stages based on environmental condition data. This tool will allow for an improvement in fishery management since in this manner the closed season can be based on the reproductive cycle. The natural population's reproductive cycle was studied for more than 2 years. The obtained gonadal and condition indexes (GI and CI) values were statistically related to environmental conditions, specifically surface seawater temperature (SST) and chlorophyll‐a (Chlo‐a) levels with these data being provided from satellite remote sensing observations (SRS). The best statistical relationship was obtained between GI and the SST registered 60 days before bivalve sampling (SST‐60). The regression equation allows for an estimate of GI value based on the SST‐60 and, as each value is related with one gonadal stage (resting, maturation, ripe), for prediction of the reproductive cycle. Therefore, the closed season can be established when most of the population is in the ripe stage and can be adjusted taking into account the possible temperature variations across the years. For ease of use, GI values estimated with this tool have also been converted using different colours onto a map of wedge clam reproductive stages in its natural beds.  相似文献   

14.
海洋渔业遥感技术及其渔场渔情应用进展   总被引:5,自引:1,他引:5  
于杰  李永振 《南方水产》2007,3(1):62-68
遥感已成为渔情分析和预报的重要技术手段之一。文章回顾了国内外渔业遥感技术的发展,对国外遥感渔场渔情分析应用现状进行了简要的评述,并详细介绍了我国在海洋渔场环境分析和渔场预报服务方面的研究进展。对我国今后的渔业遥感应用研究提出了几点建议。  相似文献   

15.
Interannual, decadal and interdecadal variations in summer plankton biomass during 1954–1994 in the whole subarctic Pacific and Bering Sea were compared among regions as well as with climatic and oceanographic conditions. The zooplankton biomass and chlorophyll concentration during the mid 1960s to early 1970s in the central and western subarctic Pacific were a few times higher than those in the preceding and following decades. The values in the eastern Bering Sea and eastern subarctic Pacific also increased in the mid 1960s, but remained at an elevated level until the end of the 1980s. These decades of higher and mid plankton biomass levels during the mid 1960s to early 1970s and mid 1970s to late 1980s correspond to the period of positive and negative values of the Northern Hemisphere zonal index (NHZI), respectively. In the decadal scale, one can see a significant positive correlation between the summer plankton biomass and the wind speed during winters in the eastern Bering Sea. The effect of grazing by biennially fluctuating Asian pink salmon on zooplankton biomass and its effect on chlorophyll concentration in the central subarctic Pacific is also significant.  相似文献   

16.
南海中部海域夏季叶绿素a浓度垂向分布特征   总被引:1,自引:0,他引:1  
根据2014年7月~8月南海中部海域(12N~18N,110E~117E) 调查获得的水柱方向上连续的叶绿素a浓度(Chl-a)数据,分析了南海中部海域夏季Chl-a垂向分布特征。结果表明:1)南海中部海域Chl-a垂向分布呈现先增加后减小的趋势,在30~70 m水层出现Chl-a高浓度区;2)次表层Chl-a最大值(subsurface chlorophyll a concentration maximum,SCM)强度变化为0.94~4.69 mgm-3, 平均为1.90 mgm-3, 是遥感表层Chl-a平均值的18.10倍,SCM深度变化为4~75.36 m,SCM厚度变化为19.01~80.36 m;3)从断面分布来看,局部海域Chl-a垂向分布受到上升流的显著影响,断面A上沿岸上升 流区表现出明显的SCM强度大、深度浅和厚度大的特征, 而断面B上中沙群岛岛礁上升流区同样表现出SCM强度大、深度浅的特征,但是厚度相对较小。  相似文献   

17.
Integrating remote sensing in fisheries control   总被引:2,自引:0,他引:2  
Abstract  To complement existing fishery control measures, in particular the Vessel Monitoring System (VMS), a pilot operational system to find fishing vessels in satellite images was set up. Radar is the mainstay of the system, which furthermore includes fully automated image processing and communication protocols with the authorities. Different image types are used to match different fisheries – oceanic, shelf and coastal. Vessel detection rates were 75–100% depending on image type and vessel size. Output of the system, in the form of an overview of vessel positions in the area highlighting any discrepancies with otherwise reported positions, can be at the authorities within 30 min of the satellite image being taken – fast enough to task airborne inspection for follow up.  相似文献   

18.
卫星遥感在海洋监测中的应用   总被引:1,自引:0,他引:1  
卫星遥感具有覆盖面积大、快速、全天时和全天候的工作能力。通过对卫星遥感所获得的海洋水温、水深、气象因素等数据进行分析,可以用于指导渔业生产、海洋灾害预警、海洋生态污染及灾害的监测,有着广泛的应用前景。  相似文献   

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