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Quality evaluation and calibration of the SWIM significant wave height product with buoy data

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Acta Oceanologica Sinica 2021年第10期40卷 187-196页

作者： Jing Ye Yong Wan Yongshou Dai college of Control Science and Engineering China University of PetroleumQingdao 266580China college of oceanography and space informatics China University of PetroleumQingdao 266580China

The significant wave height(SWH)is one of the main parameters that describe wave characteristics and is widely used in wave research *** parameters measured by radar are influenced by the offshore distance and sea *** and calibration are of great significance for radar data *** nadir beam of surface wave investigation and monitoring(SWIM)detects the global-ocean-surface *** determine the product quality of SWIM SWH,this paper carried out time-space matching between SWIM and buoy *** data qualities were evaluated under different offshore distances and sea *** improved calibration method was proposed based on sea state segmentation,which considered the distribution of the point collocation numbers in various sea *** results indicate that(1)the SWIM SWH accuracy at offshore distances greater than 50 km is higher than that at distances less than 50 km,with an root mean squared error(RMSE)of 0.2444 m,scatter index(SI)of 0.1156 and relative error(RE)of 9.97%at distances greater than 50 km and those of 0.4460 m,0.2230 and18.66%at distances less than 50 km.(2)SWIM SWH qualities are better in moderate and rough sea states with RMSEs of 0.2848 m and 0.3169 m but are worse in slight and very rough sea states.(3)The effect of the improved calibration method is superior to the traditional method in each sea state and overall data,and the RMSE of SWIM SWH is reduced from the raw 0.3135 m to 0.2859 m by the traditional method and 0.1982 m by the improved *** influence of spatiotemporal window selection on data quality evaluation was analyzed in this *** paper provides references for SWIM SWH product applications.

关键词： significant wave height SWIM buoy validation calibration

Wave Azimuth Cutoff Compensation Method and the Multisatellite Networking Mode of SAR

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Journal of Ocean University of China 2023年第3期22卷 683-696页

作者： WAN Yong CUI Kun QU Ruozhao DAI Yongshou LI Ligang QU Xiaojun ZHANG Xiaoyu college of oceanography and space informatics China University of PetroleumQingdao 266580China China college of Control Science and Engineering China University of PetroleumQingdao 266580China

Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea ***,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller *** increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked *** on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,*** results demonstrate the effectiveness of the azimuth cutoff compensation *** on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are *** highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are *** study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.

关键词： synthetic aperture radar(SAR) compensation effect cutoff wavelength multisatellite networking mode

维普期刊数据库博看期刊

Hyperspectral remote sensing identification of marine oil spills and emulsions using feature bands and double-branch dual-attention mechanism network

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Journal of Oceanology and Limnology 2024年第3期42卷 728-743页

作者： Ning ZHANG Junfang YANG Shanwei LIU Yi MA Jie ZHANG college of oceanography and space informatics China University of PetroleumQingdao 266580China First Institute of oceanography Ministry of Natural ResourcesQingdao 266061China Technology Innovation Center for Ocean Telemetry Ministry of Natural ResourcesQingdao 266061China

The accurate identification of marine oil spills and their emulsions is of great significance for emergency response to oil spill *** selection of characteristic bands with strong separability helps to realize the rapid calculation of data on aircraft or in orbit,which will improve the timeliness of oil spill emergency *** the same time,the combination of spectral and spatial features can improve the accuracy of oil spill *** ground-based experiments were designed to collect measured airborne hyperspectral data of crude oil and its emulsions,for which the multiscale superpixel level group clustering framework(MSGCF)was used to select spectral feature bands with strong *** addition,the double-branch dual-attention(DBDA)model was applied to identify crude oil and its *** with the recognition results based on original hyperspectral images,using the feature bands determined by MSGCF improved the recognition accuracy,and greatly shortened the running ***,the characteristic bands for quantifying the volume concentration of water-in-oil emulsions were determined,and a quantitative inversion model was constructed and applied to the AVIRIS image of the deepwater horizon oil spill event in *** study verified the effectiveness of feature bands in identifying oil spill pollution types and quantifying concentration,laying foundation for rapid identification and quantification of marine oil spills and their emulsions on aircraft or in orbit.

关键词： hyperspectral image spectral analysis dimensionality reduction multiscale superpixel level group clustering framework(MSGCF) double-branch dual-attention(DBDA)

Study of the ability of SWOT to detect sea surface height changes caused by internal solitary waves

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Acta Oceanologica Sinica 2024年第5期43卷 54-64页

作者： Hao Zhang Chenqing Fan Lina Sun Junmin Meng First Institute of oceanography Ministry of Natural ResourcesQingdao 266061China Technology Innovation Center for Ocean Telemetry Ministry of Natural ResourcesQingdao 266061China college of oceanography and space informatics China University of Petroleum(Huadong)Qingdao 266580China

Surface Water and Ocean Topography(SWOT)is a next-generation radar altimeter that offers high resolution,wide swath,imaging *** has provided free public data worldwide since December *** paper aims to preliminarily analyze the detection capabilities of the Ka-band radar interferometer(KaRIn)and Nadir altimeter(NALT),which are carried out by SWOT for internal solitary waves(ISWs),and to gather other remote sensing images to validate SWOT *** effectively detects ISW surface features and generates surface height variation maps reflecting the modulations induced by ***,its swath width does not completely cover the entire wave packet,and the resolution of L2/L3 level products(about 2 km)cannot be used to identify ISWs with smaller ***,significant wave height(SWH)images exhibit blocky structures that are not suitable for ISW studies;sea surface height anomaly(SSHA)images display systematic leftright *** optimize this imbalance using detrending methods;however,more precise treatment should commence with L1-level *** analysis based on L3-level SSHA data indicates that the average SSHA variation induced by ISWs ranges from 10 cm to 20 *** disturbed by ISWs record unusually elevated SWH and SSHA values,rendering the data unsuitable for analysis and necessitating targeted corrections in future retracking *** the normalized radar cross section,Ku-band and four-parameter maximum likelihood estimation retracking demonstrated greater sensitivity to minor changes in the sea surface,making them more suitable for ISW *** conclusion,SWOT demonstrates outstanding capabilities in ISW detection,significantly advancing research on the modulation of the sea surface by ISWs and remote sensing imaging mechanisms.

关键词： internal solitary waves Surface Water and Ocean Topography(SWOT) Ka-band radar interferometer(KaRIn) Nadir altimeter(NALT) sea surface height anomaly(SSHA) normalized radar cross section(NRCS)

A multi-module with a two-way feedback method for Ulva drift-diffusion

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Acta Oceanologica Sinica 2023年第12期42卷 118-134页

作者： Hui Sheng Jianmeng Li Qimao Wang Bin Zou Lijian Shi Mingming Xu Shanwei Liu Jianhua Wan Zhe Zeng Yanlong Chen college of oceanography space informatics China University of Petroleum HuadongQingdao 266580China National Satellite Ocean Application Service Beijing 100081China National Marine Environmental Monitoring Center Dalian 116023China

The outbreak of Ulva in the Yellow Sea has seriously affected marine ecology and economic ***,effective prediction of the distribution of Ulva is of great significance for disaster prevention and ***,the prediction method of Ulva is mainly based on numerical *** are two problems with these *** is that the initial distribution of Ulva is simulated using independent pixel-level ***,the influence of Ulva growth and diffusion on the drift is not ***,this paper proposes a multi-module with a two-way feedback method(MTF)to solve the above *** main contributions of our approach are summarized as ***,the initialization module,the generation and elimination module,and the drive module are composed in our ***,we proposed an initialization method using rectangle objects to simulate the Ulva distribution extracted from remote sensing ***,the drift and diffusion mechanism of the Ulva is considered to realize the two-way feedback between the generation and elimination module and the drive *** results of our experiments show that the MTF performs better than the traditional method in predicting the drift and diffusion of *** code is already publicly available at https://***/UPCGIT/A-multi-module-with-a-two-way-feedback-method-for-Ulva-drift-diffusion.

关键词： Ulva remote sensing drift diffusion feedback

Robust dual-channel correlation algorithm for complex weak target detection with wideband radar

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Journal of Systems Engineering and Electronics 2023年第5期34卷 1130-1146页

作者： DAI Yan LIU Dan LI Chuanming WEI Shaopeng HU Qingrong Beijing Institute of Radio Measurement Beijing 100854China college of oceanography and space informatics China University of Petroleum(East China)Qingdao 257099China Defense Technology Academy of China Aerospace Science and Industry Corporation Limited Beijing 100070China

In the scene of wideband radar,due to the spread of target scattering points,the attitude and angle of view of the target constantly change in the process of *** is difficult to predict,and the actual echo of multiple scattered points is not fully matched with the transmitted ***,it is challenging for the traditional matching filter method to achieve a complete matching effect in wideband echo *** addition,the energy dispersion of complex target echoes is still a problem in radar target detection under broadband ***,this paper proposes a wideband target detection method based on dualchannel correlation processing of range-extended *** method fully uses the spatial distribution characteristics of target scattering points of echo signal and the matching characteristics of the dual-channel point extension function *** radial accumulation of wideband target echo signal in the complex domain is realized through the adaptive correlation processing of a dual-channel echo *** accu-mulation effect of high matching degree is achieved to improve the detection probability and the performance of wideband ***,electromagnetic simulation experiments and measured data verify that the proposed method has the advan-tages of high signal to noise ratio(SNR)gain and high detection probability under low SNR conditions.

关键词： wideband radar target detection dual-channel cor-relation

An empirical method for joint inversion of wave and wind parameters based on SAR and wave spectrometer data

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Acta Oceanologica Sinica 2024年第5期43卷 133-144页

作者： Yong Wan Xiaona Zhang Shuyan Lang Ennan Ma Yongshou Dai college of oceanography and space informatics China University of PetroleumQingdao 266580China National Satellite Marine Application Center Beijing 100081China Key Laboratory of space Ocean Remote Sensing and Application Ministry of Natural ResourcesBeijing 100081China college of Control Science and Engineering China University of PetroleumQingdao 266580China

Synthetic aperture radar(SAR)and wave spectrometers,crucial in microwave remote sensing,play an essential role in monitoring sea surface wind and wave ***,they face inherent limitations in observing sea surface *** systems,for instance,are hindered by an azimuth cut-off phenomenon in sea surface wind field *** spectrometers,while unaffected by the azimuth cutoff phenomenon,struggle with low azimuth resolution,impacting the capture of detailed wave and wind field *** study utilizes SAR and surface wave investigation and monitoring(SWIM)data to initially extract key feature parameters,which are then prioritized using the extreme gradient boosting(XGBoost)*** research further addresses feature collinearity through a combined analysis of feature importance and correlation,leading to the development of an inversion model for wave and wind parameters based on XGBoost.A comparative analysis of this model with ERA5 reanalysis and buoy data for of significant wave height,mean wave period,wind direction,and wind speed reveals root mean square errors of 0.212 m,0.525 s,27.446°,and 1.092 m/s,compared to 0.314 m,0.888 s,27.698°,and 1.315 m/s from buoy data,*** results demonstrate the model’s effective retrieval of wave and wind ***,the model,incorporating altimeter and scatterometer data,is evaluated against SAR/SWIM single and dual payload inversion methods across different wind *** comparison highlights the model’s superior inversion accuracy over other methods.

关键词： synthetic aperture radar(SAR) wave spectrometer extreme gradient boosting(XGBoost) joint inversion method wave and wind parameters

A new decomposition model of sea level variability for the sea level anomaly time series prediction

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Journal of Oceanology and Limnology 2023年第5期41卷 1629-1642页

作者： Qinting SUN Jianhua WAN Shanwei LIU Jinghui JIANG Yasir MUHAMMAD college of oceanography and space informatics China University of Petroleum(East China)Qingdao 266580China Technology Innovation Center for Maritime Silk Road Marine Resources and Environment Networked Observation Ministry of Natural ResourcesQingdao 266580China

Rising sea level is of great significance to coastal societies;predicting sea level extent in coastal regions is *** carrying out predictions,the subsequences obtained using decomposition methods may exhibit a certain regularity and therefore can provide multidimensional information that can be used to improve prediction *** decomposition methods such as seasonal and trend decomposition using Loess(STL)focus mostly on the fluctuating trend of time series and ignore its impact on *** in the signal decomposition domain,such as variational mode decomposition(VMD),have no physical *** response to the above problems,a new decomposition method for sea level anomaly time series prediction(DMSLAP)is *** this method,the trend term in a time series can be isolated and the effects of abnormal sea level change behaviors can be *** decompose multiperiod characteristics using this method while maintaining the smoothness of the analyzed *** altimetry data from 1993 to 2020 are used in experiments conducted in the study *** results are then compared with predictions obtained using existing decomposition methods such as the STL and VMD methods and time varying filtering based on empirical mode decomposition(TVF-EMD).The performance of DMSLAP combined with a prediction method resulted in optimal sea level anomaly(SLA)predictions,with a minimum root mean square error(RMSE)of 1.40 cm and a maximum determination coefficient(R^(2))of 0.93 during *** DMSLAP method was more accurate when predicting 1-year data and 3-year *** TVF-EMD and DMSLAP methods had comparable accuracies,and the periodic term decomposed by the DMSLAP method was more in line with the actual law than that derived using the TVF-EMD ***,DMSLAP can decompose SLA time series better than existing methods and is an effective tool for obtaining short-term SLA prediction.

关键词： time series decomposition satellite altimetry China Sea and its vicinity sea level change

Algorithm based on local breeding of growing modes for convection-allowing ensemble forecasting

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Science China Earth Sciences 2018年第4期61卷 462-472页

作者： Chaohui CHEN Xiang LI Hongrang HE Jie XIANG Shenjia MA college of Meteorology and oceanography National University of Defense Technology

We propose a method based on the local breeding of growing modes(LBGM) considering strong local weather characteristics for convection-allowing ensemble forecasting. The impact radius was introduced in the breeding of growing modes to develop the LBGM method. In the local breeding process, the ratio between the root mean square error(RMSE) of local space forecast at each grid point and that of the initial full-field forecast is computed to rescale perturbations. Preliminary evaluations of the method based on a nature run were performed in terms of three aspects: perturbation structure, spread,and the RMSE of the forecast. The experimental results confirm that the local adaptability of perturbation schemes improves after rescaling by the LBGM method. For perturbation physical variables and some near-surface meteorological elements, the LBGM method could increase the spread and reduce the RMSE of forecast,improving the performance of the ensemble forecast *** addition, different from those existing methods of global orthogonalization approach, this new initial-condition perturbation method takes into full consideration the local characteristics of the convective-scale weather system, thus making convectionallowing ensemble forecast more accurate.

关键词： Convection-allowing ensemble forecasting Local breeding of growing modes Perturbation structure Spread Root mean square error of forecast