Spatial interpolation is a common tool used in the study of fishery ecology, especially for the construction of ecosystem models. To develop an appropriate interpolation method of determining fishery resources density...Spatial interpolation is a common tool used in the study of fishery ecology, especially for the construction of ecosystem models. To develop an appropriate interpolation method of determining fishery resources density in the Yellow Sea, we tested four frequently used methods, including inverse distance weighted interpolation(IDW), global polynomial interpolation(GPI), local polynomial interpolation(LPI) and ordinary kriging(OK).A cross-validation diagnostic was used to analyze the efficacy of interpolation, and a visual examination was conducted to evaluate the spatial performance of the different methods. The results showed that the original data were not normally distributed. A log transformation was then used to make the data fit a normal distribution. During four survey periods, an exponential model was shown to be the best semivariogram model in August and October 2014, while data from January and May 2015 exhibited the pure nugget effect.Using a paired-samples t test, no significant differences(P>0.05) between predicted and observed data were found in all four of the interpolation methods during the four survey periods. Results of the cross-validation diagnostic demonstrated that OK performed the best in August 2014, while IDW performed better during the other three survey periods. The GPI and LPI methods had relatively poor interpolation results compared to IDW and OK. With respect to the spatial distribution, OK was balanced and was not as disconnected as IDW nor as overly smooth as GPI and LPI, although OK still produced a few 'bull's-eye' patterns in some areas.However, the degree of autocorrelation sometimes limits the application of OK. Thus, OK is highly recommended if data are spatially autocorrelated. With respect to feasibility and accuracy, we recommend IDW to be used as a routine interpolation method. IDW is more accurate than GPI and LPI and has a combination of desirable properties, such as easy accessibility and rapid processing.展开更多
The idea of modified water masses is introduced and a cluster analysis is used for determining the boundary of modified water masses and its variety in the shallow water area of the Huanghai Sea (Yellow Sea) and the E...The idea of modified water masses is introduced and a cluster analysis is used for determining the boundary of modified water masses and its variety in the shallow water area of the Huanghai Sea (Yellow Sea) and the East China Sea. According to the specified standards to make the cluster, we have determined the number and boundary of the water masses and the mixed zones.The results obtained by the cluster method show that there are eight modified water masses in this area. According to the relative index of temperature and salinity,the modified water masses are divided into nine different characteristic parts. The water, masses may also be divided into three salinity types. On the TS-Diagram, the points concerning temperature and safinity of different modified mater masses are distributed around a curve, from which the characteristics of gradual modification may be embodied. The variation ranges of different modified water masses are all large, explaining the intensive modification of water masses in展开更多
传统的基于有限元的建模和计算方法在中高频条件下得出的结果不精确,因此,整流罩在中高频条件下结构振动、声辐射以及声振耦合等问题,可以用统计能量分析(SEA)方法和有限元-统计能量分析(FE-SEA)法进行分析。通过ESI VA ONE软件建立整...传统的基于有限元的建模和计算方法在中高频条件下得出的结果不精确,因此,整流罩在中高频条件下结构振动、声辐射以及声振耦合等问题,可以用统计能量分析(SEA)方法和有限元-统计能量分析(FE-SEA)法进行分析。通过ESI VA ONE软件建立整流罩的结构FE模型以及划分内部声腔子系统,分析不同子系统在声振条件下内部声压级的大小。仿真结果表明在声振耦合条件下,整流罩的声腔子系统在不同的部位声压级大小不同,以及声压级大小随频率变化。展开更多
In order to suppress complex mixing noise in low-illumination images for wide-area search of nighttime sea surface,a model based on total variation(TV)and split Bregman is proposed in this paper.A fidelity term based ...In order to suppress complex mixing noise in low-illumination images for wide-area search of nighttime sea surface,a model based on total variation(TV)and split Bregman is proposed in this paper.A fidelity term based on L1 norm and a fidelity term based on L2 norm are designed considering the difference between various noise types,and the regularization mixed first-order TV and second-order TV are designed to balance the influence of details information such as texture and edge for sea surface image.The final detection result is obtained by using the high-frequency component solved from L1 norm and the low-frequency component solved from L2 norm through wavelet transform.The experimental results show that the proposed denoising model has perfect denoising performance for artificially degraded and low-illumination images,and the result of image quality assessment index for the denoising image is superior to that of the contrastive models.展开更多
Precise measurements of the CO2 gas transfer across the air-sea interface provide a better under- standing of the global carbon cycle. The air-sea CO2 fluxes are obtained by the eddy covariance method and the bulk met...Precise measurements of the CO2 gas transfer across the air-sea interface provide a better under- standing of the global carbon cycle. The air-sea CO2 fluxes are obtained by the eddy covariance method and the bulk method from a buoy observation in the northern Huanghai sea. The effects of buoy motion on flux calculated by the eddy covariance method are demonstrated. The research shows that a motion correction can improve the correlation coefficient between the C02 fluxes esti- mated from two different levels. Without the CO2-H20 cross-correlation correction which is termed as PKT correction, the air-sea CO2 fluxes estimated by eddy covariance method using the motion corrected data are nearly an order of magnitude larger than those estimated by the bulk method. After the CO2-H20 cross-correlation correction, some eddy covariance CO2 fluxes indeed become closer to the bulk CO2 flux, whereas some are overcorrected which are in response to small water vapor flux.展开更多
In this paper, on the basis of the heat conduction equation without consideration of the advection and turbulence effects, one-dimensional model for describing surface sea temperature ( T1), bottom sea temperature ( T...In this paper, on the basis of the heat conduction equation without consideration of the advection and turbulence effects, one-dimensional model for describing surface sea temperature ( T1), bottom sea temperature ( Tt ) and the thickness of the upper homogeneous layer ( h ) is developed in terms of the dimensionless temperature θT and depth η and self-simulation function θT - f(η) of vertical temperature profile by means of historical temperature data.The results of trial prediction with our one-dimensional model on T, Th, h , the thickness and gradient of thermocline are satisfactory to some extent.展开更多
基金The National Basic Research Program of China under contract No.2015CB453303the National Natural Science Foundation of China under contract No.U1405234+1 种基金the Aoshan Science&Technology Innovation Program under contract No.2015ASKJ02-05the Special Fund of the Taishan Scholar Project
文摘Spatial interpolation is a common tool used in the study of fishery ecology, especially for the construction of ecosystem models. To develop an appropriate interpolation method of determining fishery resources density in the Yellow Sea, we tested four frequently used methods, including inverse distance weighted interpolation(IDW), global polynomial interpolation(GPI), local polynomial interpolation(LPI) and ordinary kriging(OK).A cross-validation diagnostic was used to analyze the efficacy of interpolation, and a visual examination was conducted to evaluate the spatial performance of the different methods. The results showed that the original data were not normally distributed. A log transformation was then used to make the data fit a normal distribution. During four survey periods, an exponential model was shown to be the best semivariogram model in August and October 2014, while data from January and May 2015 exhibited the pure nugget effect.Using a paired-samples t test, no significant differences(P>0.05) between predicted and observed data were found in all four of the interpolation methods during the four survey periods. Results of the cross-validation diagnostic demonstrated that OK performed the best in August 2014, while IDW performed better during the other three survey periods. The GPI and LPI methods had relatively poor interpolation results compared to IDW and OK. With respect to the spatial distribution, OK was balanced and was not as disconnected as IDW nor as overly smooth as GPI and LPI, although OK still produced a few 'bull's-eye' patterns in some areas.However, the degree of autocorrelation sometimes limits the application of OK. Thus, OK is highly recommended if data are spatially autocorrelated. With respect to feasibility and accuracy, we recommend IDW to be used as a routine interpolation method. IDW is more accurate than GPI and LPI and has a combination of desirable properties, such as easy accessibility and rapid processing.
文摘The idea of modified water masses is introduced and a cluster analysis is used for determining the boundary of modified water masses and its variety in the shallow water area of the Huanghai Sea (Yellow Sea) and the East China Sea. According to the specified standards to make the cluster, we have determined the number and boundary of the water masses and the mixed zones.The results obtained by the cluster method show that there are eight modified water masses in this area. According to the relative index of temperature and salinity,the modified water masses are divided into nine different characteristic parts. The water, masses may also be divided into three salinity types. On the TS-Diagram, the points concerning temperature and safinity of different modified mater masses are distributed around a curve, from which the characteristics of gradual modification may be embodied. The variation ranges of different modified water masses are all large, explaining the intensive modification of water masses in
文摘传统的基于有限元的建模和计算方法在中高频条件下得出的结果不精确,因此,整流罩在中高频条件下结构振动、声辐射以及声振耦合等问题,可以用统计能量分析(SEA)方法和有限元-统计能量分析(FE-SEA)法进行分析。通过ESI VA ONE软件建立整流罩的结构FE模型以及划分内部声腔子系统,分析不同子系统在声振条件下内部声压级的大小。仿真结果表明在声振耦合条件下,整流罩的声腔子系统在不同的部位声压级大小不同,以及声压级大小随频率变化。
基金supported by the Major Projects of the Ministry of Science and Technology(No.2016YFB0501202)the Natural Science Foundation of Jilin Province,China(No.20170101164JC)
文摘In order to suppress complex mixing noise in low-illumination images for wide-area search of nighttime sea surface,a model based on total variation(TV)and split Bregman is proposed in this paper.A fidelity term based on L1 norm and a fidelity term based on L2 norm are designed considering the difference between various noise types,and the regularization mixed first-order TV and second-order TV are designed to balance the influence of details information such as texture and edge for sea surface image.The final detection result is obtained by using the high-frequency component solved from L1 norm and the low-frequency component solved from L2 norm through wavelet transform.The experimental results show that the proposed denoising model has perfect denoising performance for artificially degraded and low-illumination images,and the result of image quality assessment index for the denoising image is superior to that of the contrastive models.
基金The National Basic Research Program of China under contract No. 2011CB403501the Public Science and Technology Research Funds Projects of Ocean of the State oceanic Administration of China under contract No. 200905012-9+1 种基金the Fund for Creative Research Groups by the National Natural Science Foundation of China under contract No. 41121064the Open Research Foundation for the key Laboratory of Ocean Circulation and Waves.Institute of Oceanology,Chinese Academy of Sciences of China under contract No.KLOCAW1207
文摘Precise measurements of the CO2 gas transfer across the air-sea interface provide a better under- standing of the global carbon cycle. The air-sea CO2 fluxes are obtained by the eddy covariance method and the bulk method from a buoy observation in the northern Huanghai sea. The effects of buoy motion on flux calculated by the eddy covariance method are demonstrated. The research shows that a motion correction can improve the correlation coefficient between the C02 fluxes esti- mated from two different levels. Without the CO2-H20 cross-correlation correction which is termed as PKT correction, the air-sea CO2 fluxes estimated by eddy covariance method using the motion corrected data are nearly an order of magnitude larger than those estimated by the bulk method. After the CO2-H20 cross-correlation correction, some eddy covariance CO2 fluxes indeed become closer to the bulk CO2 flux, whereas some are overcorrected which are in response to small water vapor flux.
文摘In this paper, on the basis of the heat conduction equation without consideration of the advection and turbulence effects, one-dimensional model for describing surface sea temperature ( T1), bottom sea temperature ( Tt ) and the thickness of the upper homogeneous layer ( h ) is developed in terms of the dimensionless temperature θT and depth η and self-simulation function θT - f(η) of vertical temperature profile by means of historical temperature data.The results of trial prediction with our one-dimensional model on T, Th, h , the thickness and gradient of thermocline are satisfactory to some extent.
