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基于PCA-BP特征工程的近海单点海温预报技术及应用
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作者 何恩业 李琼 +3 位作者 张聿柏 匡晓迪 王源 朱现晔 《海洋预报》 CSCD 北大核心 2023年第3期35-44,共10页
本文将主成分分析方法(Principal Components Analysis,PCA)和误差后传(Back Propagation,BP)神经网络相结合,建立了一种PCA-BP特征工程的近海单点海温智能预报模型,并对山东荣成近岸海域气象数值预报产品和在线海温监测仪连续观测数据... 本文将主成分分析方法(Principal Components Analysis,PCA)和误差后传(Back Propagation,BP)神经网络相结合,建立了一种PCA-BP特征工程的近海单点海温智能预报模型,并对山东荣成近岸海域气象数值预报产品和在线海温监测仪连续观测数据开展了释用技术研究和应用。2021年业务化运行结果显示:该预报模型具有占用内存小、运行速度快、预报误差低的优点,相比近岸基础单元数值预报和经验预报的24 h均方根误差降幅达1.0℃和0.8℃,均方根相对误差降幅达12%~14%,未来48 h和72 h的预报误差也降幅明显,预报计算时间小于10 s,并将预报时效进一步向前扩展了3 d,达到144 h。 展开更多
关键词 海温预报 主成分分析 神经网络 特征工程 释用技术
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基于主成分分析和LSTM神经网络的海温预报模型 被引量:3
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作者 李竞时 匡晓迪 +4 位作者 李琼 何恩业 张聿柏 袁承仪 张延琳 《海洋预报》 CSCD 北大核心 2023年第2期1-10,共10页
利用荣成、海阳两站的自建浮标海温观测数据以及区域大气模式WRF(Weather Research and Forecasting)的气象数值预报数据,基于主成分分析(Principal Component Analysis,PCA)法和长短时记忆(Long Short-Term Memory,LSTM)神经网络,提出... 利用荣成、海阳两站的自建浮标海温观测数据以及区域大气模式WRF(Weather Research and Forecasting)的气象数值预报数据,基于主成分分析(Principal Component Analysis,PCA)法和长短时记忆(Long Short-Term Memory,LSTM)神经网络,提出了适用于单站海表温度预报的PCALSTM海温预报模型。该模型可以提供24~120 h预报时效的海温预报,预测效果比数值模型和统计模型明显提高。 展开更多
关键词 主成分分析 长短时记忆神经网络 海温预报
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基于U-Net的海洋锋智能检测模型
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作者 任诗鹤 韩焱红 +4 位作者 李竞时 赵亚明 匡晓迪 吴湘玉 杨晓峰 《空间科学学报》 CAS CSCD 北大核心 2023年第6期1091-1099,共9页
海洋锋作为海洋中两种不同性质的水体之间的边界,对渔业和海洋环境保护等许多领域有重要影响,如何快速准确实现海洋锋的自动检测和识别对于海洋监测和预报具有重要的科学意义。将深度学习图像分割网络与提取锋面特征的方法相结合,利用基... 海洋锋作为海洋中两种不同性质的水体之间的边界,对渔业和海洋环境保护等许多领域有重要影响,如何快速准确实现海洋锋的自动检测和识别对于海洋监测和预报具有重要的科学意义。将深度学习图像分割网络与提取锋面特征的方法相结合,利用基于U-Net架构的实例分割模型,分别建立海洋锋区和锋面中心线的智能检测模型,同时在编解码过程中采用残差学习单元对模型特征提取网络进行改进。研究结果表明,锋面智能检测模型能够准确提取先前锋面检测算法所识别的锋区和锋面中心线特征,Dice系数分别达到了0.92和0.97,达到了很好的检测效果。同时,利用不同锋面阈值得到的样本数据对模型进行训练,比较结果表明,降低样本集阈值之后模型精度有了显著的提升。 展开更多
关键词 海洋锋 海表温度 深度学习 U-Net
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The error source analysis of oil spill transport modeling: a case study 被引量:6
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作者 LI Yan ZHU Jiang +1 位作者 WANG Hui kuang xiaodi 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第10期41-47,共7页
Numerical modeling is an important tool to study and predict the transport of oil spills. However, the accu- racy of numerical models is not always good enough to provide reliable information for oil spill transport. ... Numerical modeling is an important tool to study and predict the transport of oil spills. However, the accu- racy of numerical models is not always good enough to provide reliable information for oil spill transport. It is necessary to analyze and identify major error sources for the models. A case study was conducted to analyze error sources of a three-dimensional oil spill model that was used operationally for oil spill forecast- ing in the National Marine Environmental Forecasting Center (NMEFC), the State Oceanic Administration, China. On June 4, 2011, oil from sea bed spilled into seawater in Penglai 19-3 region, the largest offshore oil field of China, and polluted an area of thousands of square kilometers in the Bohai Sea. Satellite remote sensing images were collected to locate oil slicks. By performing a series of model sensitivity experiments with different wind and current forcings and comparing the model results with the satellite images, it was identified that the major errors of the long-term simulation for oil spill transport were from the wind fields, and the wind-induced surface currents. An inverse model was developed to estimate the temporal variabil- ity of emission intensity at the oil spill source, which revealed the importance of the accuracy in oil spill source emission time function. 展开更多
关键词 error source oil spill lagrangian random walk
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老年人失能及其测评工具的研究进展 被引量:9
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作者 杨黎 邝小迪 苏爱华 《护理研究》 北大核心 2019年第10期1722-1726,共5页
对失能的内涵、特征及老年人功能状况测评工具进行综述,为全面准确评估老年人的失能状况提供依据。
关键词 失能老人 功能状况 测评工具 日常生活能力
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Linkage Between Winter Temperatures in the Yellow Sea and Atmospheric Circulation Indices 被引量:1
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作者 YUAN Chengyi WEI Hao +1 位作者 LUO Xiaofan kuang xiaodi 《Journal of Ocean University of China》 SCIE CAS CSCD 2019年第2期261-270,共10页
This study investigated the linkage between winter temperature in the Yellow Sea(YS), China, and atmospheric indices and established this linkage through statistical models. The water temperature was obtained through ... This study investigated the linkage between winter temperature in the Yellow Sea(YS), China, and atmospheric indices and established this linkage through statistical models. The water temperature was obtained through hindcast simulation using a global–regional nested ocean model for the period of 1958–2007. The interannual variations of the simulated temperature were validated using satellite and in-situ observations. In the YS, the winter sea surface temperature(SST) had obvious interannual variations, with the maximum SST exceeding 2℃, and a significant shift from the cold to warm phase during 1988–1989. Based on the mechanism study, statistical models for the variations of water temperature in the YS were established using suitable atmospheric indices as predictors. For the northern YS(NYS) and the coastal region of the southern YS(SYS), statistical models of SST were established using linear regression based on the December–January–February mean Arctic oscillation index(AOI), representing the dominant large-scale atmospheric variability in boreal winter. For the YS warm current(YSWC) region, statistical models were established using both the AOI and the first principal component of the local wind stress curl(PC1-Curl), derived from the empirical orthogonal functions analysis. The PC1-Curl represents the influence of the local wind stress curl on the west-to-east shifts of the YSWC pathway. The applications proved that the models presented in this study have the ability to estimate winter temperatures in the YS within the recent years. 展开更多
关键词 water temperature statistical model INTERANNUAL VARIATIONS atmospheric VARIABILITY empirical ORTHOGONAL function analysis
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