2014年春季渤海浮游植物群落结构   总被引：2，自引：1，他引：1  

张雪  王俊  高燕  王宏  马武  刘克奉  陈卫 《海洋科学》2020,44(6):45-55

基于2014年春季在渤海进行的水文、化学和生物方面的综合大面调查，研究了渤海浮游植物群落的结构特征，并结合文献资料，分析影响浮游植物群落结构形成的原因。结果显示：2014年渤海春季共鉴定浮游植物3门29属50种，以硅藻为主，还有少数甲藻和金藻。其中，硅藻门中圆筛藻属的种类最多，共12种，其次为角毛藻属，共5种。浮游植物总细胞丰度介于1.08×10⁴~181.09×10⁴个/m³，平均为25.47×10⁴个/m³。硅藻与甲藻细胞丰度比值为12：1，硅藻在物种数量和细胞丰度上均占有绝对优势，为渤海浮游植物的主要类群。浮游植物优势种主要为密联角毛藻（Chaetoceros densus）、斯氏几内亚藻（Guinardia striata）、具槽帕拉藻（Paralia sulcata）和夜光藻（Noctiluca scintillans）。渤海春季浮游植物群落多样性水平较低，且分布不均。渤海中部和渤海海峡海域由于单一优势种过量繁殖导致群落稳定性较差。与历史同期资料对比，渤海海域浮游植物群落出现明显的物种演替现象，角毛藻的优势地位显著性下降，斯氏几内亚藻首次在渤海大面调查中被记录为优势种。本研究为今后渤海环境生态系统和渔业资源变动的研究提供重要基础资料和参考依据。  相似文献   

西北太平洋低纬度区域海水中溶解氨基酸的分布及组成研究   总被引：1，自引：1，他引：0  

张宁  陈岩  高先池  杨桂朋 《海洋科学》2020,44(5):60-70

本文对2018年秋季西北太平洋低纬度区域上层海洋(5~200 m)中溶解氨基酸(THAA)的分布和组成进行了研究。结果表明,该海域表层海水中THAA的浓度范围为0.40~0.97μmol/L,平均浓度为0.58±0.14μmol/L;5~200m垂直断面上THAA的平均浓度为0.59±0.16μmol/L,范围为0.30~1.05μmol/L。调查海域内THAA浓度明显低于中国近海,在5~200m内的垂直分布基本表现出随深度增加而增加的趋势。将表层和垂直水体中的THAA分别与DOC、Chla等环境因子进行相关性分析,结果显示均无显著相关性。西北太平洋低纬度区域海水中的优势氨基酸是天冬氨酸(Asp)、谷氨酸(Glu)、丝氨酸(Ser)、甘氨酸(Gly)、苏氨酸(Thr)和丙氨酸(Ala)。基于氨基酸的碳归一化产率(THAA-C%)、降解因子(DI)值,表明该海域表层海水中的有机质降解程度较高,且随深度的增加而降低。  相似文献   

盐度胁迫对黄条鰤消化生理和抗应激指标的影响     

史宝  柳学周  曹亚男  刘永山  徐永江  姜燕  王滨 《海洋科学》2020,44(6):64-72

为探讨盐度突变对黄条鰤（Seriola aureovittata）幼鱼消化酶活力和抗应激指标的影响，设计了采用自然海水养殖的对照组盐度29（S29）和实验组盐度分别为35（S35）、15（S15）、10（S10）和5（S5），对黄条鰤进行了120 h的急性胁迫实验，测定了各盐度条件下消化酶活力、超氧化物歧化酶（SOD）活力及甲状腺激素（T4）浓度的变化。结果显示：黄条鰤胃、肠、肝脏和幽门盲囊的脂肪酶活力，6 h时实验组与对照组差异不显著（P>0.05），12 h后呈现随时间的增长而活力降低的现象，且实验组显著低于对照组（P<0.05）；蛋白酶活力胁迫24 h后，实验组显著低于对照组（P<0.05）。胃和肝脏蛋白酶活力胁迫6~12 h，S35显著高于对照组（P<0.05）。胃和肠的淀粉酶活力胁迫后，实验组均显著低于对照组（P<0.05）；肝脏淀粉酶活力胁迫6~12 h，S35均高于对照组，24 h后显著低于对照组（P<0.05）。S5的SOD活力随着时间的增加而降低，且差异显著（P<0.05）；S15和S35在120 h时SOD活力降低并接近对照组。各盐度组血清中T4的浓度在6~96 h显著高于对照组（P<0.05），随后降低并在120 h时趋于稳定。综上所述，盐度胁迫对黄条鰤幼鱼消化酶活力、SOD活力和T4浓度影响较大，黄条鰤对盐度变化有较强的调节能力，相关生理指标变化可为黄条鰤养殖提供参考。  相似文献   

南海北部夏季定点实测波浪统计分析     

卢燕  王冠琳  王道龙  王新怡 《海岸工程》2020,39(3):213-223

  相似文献   

一种利用浮标站资料改进海浪模式有效波高预报的方法     

龚 《海洋预报》2020,37(1):50-54

基于浮标站海浪历史数据,利用回归分析方法建立了海浪数值模式有效波高预报产品的一元二次回归方程订正统计模型。通过2017年7月1日-2018年10月10日期间业务试运行结果发现:订正方程能有效改善有效波高数值预报产品的预报精度,且预报时效越短订正效果越显著。其中,第6~11 h预报时效内的订正前后平均绝对误差值减小0.17~0. 241 m,第6~18 h预报时效内订正前后均方根误差减小幅度为0.103~0. 28 m。这说明应用订正统计模型对海浪模式输出产品进行订正,也是改进海浪模式预报准确率的一种有效途径。  相似文献   

Prediction of 3D size and shape descriptors of irregular granular particles from projected 2D images     

Su  D.  Yan  W. M. 《Acta Geotechnica》2020,15(6):1533-1555

Acta Geotechnica - Macroscopic mechanical properties of granular materials are closely related to particle morphology. For practical reasons, the morphological features are commonly examined from...  相似文献   

不同DEM数据源的艾比湖流域仿真水系对比   总被引：1，自引：0，他引：1  

任岩  张飞  王娟  张月  李瑞 《测绘科学》2018,(3):35-44,57

针对干旱半干旱地区内陆河流域在仿真水系模拟方面研究较少和数据适用性的问题,该文提出利用SRTM3-DEM和ASTER-GDEM两种数据源对艾比湖流域进行仿真水系模拟和精度对比的研究。采用ArcGIS Hydrology模型分别对两种DEM进行水系模拟,通过多次设置参数和阈值,实现了不同水平分辨率和不同阈值河网水系的对比分析;然后利用Google Map河流数据和实测水系数据进行精度验证,同时采用"套河差"算法研究水系的差异。结果表明:SRTM3-DEM模拟的河网水系与实际水系更接近,吻合精度较高;DEM的坡度和水平分辨率对模拟水系的影响不大,但DEM的垂直精度对模拟水系的吻合精度起控制作用。本研究为艾比湖流域在水文方面的研究提供了一定的参照和依据。  相似文献   

Geometric-constrained multi-view image matching method based on semi-global optimization     

Wenhao Zhao  Li Yan 《地球空间信息科学学报》2018,21(2):115-126

Targeting at a reliable image matching of multiple remote sensing images for the generation of digital surface models, this paper presents a geometric-constrained multi-view image matching method, based on an energy minimization framework. By employing a geometrical constraint, the cost value of the energy function was calculated from multiple images, and the cost value was aggregated in an image space using a semi-global optimization approach. A homography transform parameter calculation method is proposed for fast calculation of projection pixel on each image when calculating cost values. It is based on the known interior orientation parameters, exterior orientation parameters, and a given elevation value. For an efficient and reliable processing of multiple remote sensing images, the proposed matching method was performed via a coarse-to-fine strategy through image pyramid. Three sets of airborne remote sensing images were used to evaluate the performance of the proposed method. Results reveal that the multi-view image matching can improve matching reliability. Moreover, the experimental results show that the proposed method performs better than traditional methods.  相似文献   

Image-aided platform orientation determination with a GNSS/low-cost IMU system using robust-adaptive Kalman filter     

Wenlin Yan  Luísa Bastos  José A. Gonçalves  Américo Magalhães  Tianhe Xu 《GPS Solutions》2018,22(1):12

The availability of miniaturized sensors with enhanced capabilities, new methods for image processing, and easy access to small and low-weight airborne platforms for data acquisition, including unmanned vehicles, opens new possibilities for geodetic navigation applications and developing new developments in sensor fusion. In this context, the development of efficient methods, based on low-cost sensors, to extract precise georeferenced information from digital cameras is of utmost interest. We present a method to improve the performance of the integration of GNSS/low-cost IMU by exploiting the orientation changes retrieved from digital images. In this work, a robust-adaptive Kalman filter is also introduced to further improve the performance of the method deployed. The adaptive factor and the robust factor accomplished are determined by innovation information and the threshold value of orientation changes between consecutive images. Results from airborne tests used to assess the performance of the method are presented. The results show that using a non-metric camera, the Euler angle estimation accuracy of the GNSS/low-cost IMU integration can be improved to be close to 0.5 degree and an additional improvement, which can reach 59%, can be achieved after using the robust-adaptive Kalman filter.  相似文献   

Seasonal and Diurnal Variations of Cloud Systems over the Eastern Tibetan Plateau and East China: A Cloud-resolving Model Study     

Jinghua CHEN  Xiaoqing WU  Chunsong LU  Yan YIN 《大气科学进展》2022,39(7):1034-1049

The seasonal and diurnal variations of cloud systems are profoundly affected by the large-scale and local environments. In this study, a one-year-long simulation was conducted using a two-dimensional cloud-resolving model over the Eastern Tibetan Plateau (ETP) and two subregions of Eastern China: Southern East China and Central East China. Deep convective clouds (DCCs) rarely occur in the cold season over ETP, whereas DCCs appear in Eastern China throughout the year, and the ETP DCCs are approximately 20%?30% shallower than those over Eastern China. Most strong rainfall events (precipitation intensity, PI> 2.5 mm h^?1) in Eastern China are related to warm-season DCCs with ice cloud processes. Because of the high elevation of the ETP, the warm-season freezing level is lower than in Eastern China, providing favorable conditions for ice cloud processes. DCCs are responsible for the diurnal variations of warm-season rainfall in all three regions. Warm-season DCCs over the ETP have the greatest total cloud water content and frequency in the afternoon, resulting in an afternoon rainfall peak. In addition, rainfall events in the ETP also exhibit a nocturnal peak in spring, summer, and autumn due to DCCs. Strong surface heat fluxes around noon can trigger or promote DCCs in spring, summer, and autumn over the ETP but produce only cumulus clouds in winter due to the cold and dry environment.  相似文献