The mean wavelength of ocean waves is an important environmental parameter in ocean engineering. Owing to the difficulty in its measurement, it is usually estimated from the mean wave period according to the theoretic...The mean wavelength of ocean waves is an important environmental parameter in ocean engineering. Owing to the difficulty in its measurement, it is usually estimated from the mean wave period according to the theoretical relationship between the two wave parameters. However, the relationships that have been proposed are not very satisfactory. In this paper, some suggestions are made for improvement of the data analysis method by which the mean wavelength is estimated from surface elevation records. Laboratory experiments are conducted in a wind-wave flume, and a new relationship between the mean wavelength and mean wave period is obtained by the application of the improved data analysis method. The new relationship deviates from that of Xu et al. （1999） while it is very close to the one proposed by Kinsman （1965）, although the last one is theoretically deficient.展开更多
Wind and wave data are essential in climatological and engineering design applications.In this study,data from 15 buoys located throughout the South China Sea(SCS)were used to evaluate the ERA5 wind and wave data.Appl...Wind and wave data are essential in climatological and engineering design applications.In this study,data from 15 buoys located throughout the South China Sea(SCS)were used to evaluate the ERA5 wind and wave data.Applicability assessment are beneficial for gaining insight into the reliability of the ERA5 data in the SCS.The bias range between the ERA5 and observed wind-speed data was-0.78-0.99 m/s.The result indicates that,while the ERA5 wind-speed data underestimation was dominate,the overestimation of such data existed as well.Additionally,the ERA5 data underestimated annual maximum wind-speed by up to 38%,with a correlation coefficient>0.87.The bias between the ERA5 and observed significant wave height(SWH)data varied from-0.24 to 0.28 m.And the ERA5 data showed positive SWH bias,which implied a general underestimation at all locations,except those in the Beibu Gulf and centralwestern SCS,where overestimation was observed.Under extreme conditions,annual maximum SWH in the ERA5 data was underestimated by up to 30%.The correlation coefficients between the ERA5 and observed SWH data at all locations were greater than 0.92,except in the central-western SCS(0.84).The bias between the ERA5 and observed mean wave period(MWP)data varied from-0.74 to 0.57 s.The ERA5 data showed negative MWP biases implying a general overestimation at all locations,except for B1(the Beibu Gulf)and B7(the northeastern SCS),where underestimation was observed.The correlation coefficient between the ERA5 and observed MWP data in the Beibu Gulf was the smallest(0.56),and those of other locations fluctuated within a narrow range from 0.82 to 0.90.The intercomparison indicates that during the analyzed time-span,the ERA5 data generally underestimated wind-speed and SWH,but overestimated MWP.Under non-extreme conditions,the ERA5 wind-speed and SWH data can be used with confidence in most regions of the SCS,except in the central-western SCS.展开更多
The purpose is to study the accuracy of ocean wave parameters retrieved from C-band VV-polarization Sentinel-1Synthetic Aperture Radar（SAR） images, including both significant wave height（SWH） and mean wave period...The purpose is to study the accuracy of ocean wave parameters retrieved from C-band VV-polarization Sentinel-1Synthetic Aperture Radar（SAR） images, including both significant wave height（SWH） and mean wave period（MWP）, which are both calculated from a SAR-derived wave spectrum. The wind direction from in situ buoys is used and then the wind speed is retrieved by using a new C-band geophysical model function（GMF） model,denoted as C-SARMOD. Continuously, an algorithm parameterized first-guess spectra method（PFSM） is employed to retrieve the SWH and the MWP by using the SAR-derived wind speed. Forty-five VV-polarization Sentinel-1 SAR images are collected, which cover the in situ buoys around US coastal waters. A total of 52 subscenes are selected from those images. The retrieval results are compared with the measurements from in situ buoys. The comparison performs good for a wind retrieval, showing a 1.6 m/s standard deviation（STD） of the wind speed, while a 0.54 m STD of the SWH and a 2.14 s STD of the MWP are exhibited with an acceptable error.Additional 50 images taken in China＇s seas were also implemented by using the algorithm PFSM, showing a 0.67 m STD of the SWH and a 2.21 s STD of the MWP compared with European Centre for Medium-range Weather Forecasts（ECMWF） reanalysis grids wave data. The results indicate that the algorithm PFSM works for the wave retrieval from VV-polarization Sentinel-1 SAR image through SAR-derived wind speed by using the new GMF C-SARMOD.展开更多
目的探讨血栓通注射液联合鼠神经生长因子治疗非动脉炎性前部缺血性视神经病变(AION)的疗效观察。方法选取2013年6月—2015年6月沈阳市第四人民医院眼科收治的非动脉炎性AION患者88例,按治疗方案的差别将患者分为对照组和治疗组,每组各4...目的探讨血栓通注射液联合鼠神经生长因子治疗非动脉炎性前部缺血性视神经病变(AION)的疗效观察。方法选取2013年6月—2015年6月沈阳市第四人民医院眼科收治的非动脉炎性AION患者88例,按治疗方案的差别将患者分为对照组和治疗组,每组各44例。对照组肌肉注射注射用鼠神经生长因子,18μg/次加入到0.9%生理盐水或灭菌注射用水2 m L中溶解,1次/d。治疗组在对照组治疗基础上静脉滴注血栓通注射液,5 m L加入到0.9%生理盐水250 m L,1次/d。两组患者均连续治疗4周。观察两组的临床疗效,同时比较两组视野缺损(MD)、P100波潜伏期、视盘各象限视神经纤维层厚度(ATRNFL)、视力提高行数。结果治疗后,对照组和治疗组的总有效率分别为77.27%、93.18%,两组比较差异有统计学意义(P<0.05)。治疗后,两组患者MD、P100潜伏期较治疗前显著减小,同组治疗前后差异具有统计学意义(P<0.05);且治疗组的改善程度优于对照组,两组比较差异具有统计学意义(P<0.05)。治疗后,两组ATRNFL均较治疗前减小,但治疗后治疗组ATRNFL较对照组高,两组比较差异具有统计学意义(P<0.05);并且治疗后对照组ATRNFL较正常值低。治疗组的视力提高行数高于对照组,两组比较差异具有统计学意义(P<0.05)。结论血栓通注射液联合鼠神经生长因子治疗非动脉炎性AION具有较好的临床疗效,可明显改善视力,有效提高视野,具有一定的临床推广应用价值。展开更多
文摘The mean wavelength of ocean waves is an important environmental parameter in ocean engineering. Owing to the difficulty in its measurement, it is usually estimated from the mean wave period according to the theoretical relationship between the two wave parameters. However, the relationships that have been proposed are not very satisfactory. In this paper, some suggestions are made for improvement of the data analysis method by which the mean wavelength is estimated from surface elevation records. Laboratory experiments are conducted in a wind-wave flume, and a new relationship between the mean wavelength and mean wave period is obtained by the application of the improved data analysis method. The new relationship deviates from that of Xu et al. （1999） while it is very close to the one proposed by Kinsman （1965）, although the last one is theoretically deficient.
基金Supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2021SP102)the Key Laboratory of Marine Environmental Survey Technology and Application+2 种基金Ministry of Natural Resources(Nos.MESTA-2020-C003,MESTA-2020-C004)the Key Research and Development Project of Guangdong Province(No.2020B1111020003)the Science and Technology Research Project of Jiangxi Provincial Department of Education(No.GJJ200330)。
文摘Wind and wave data are essential in climatological and engineering design applications.In this study,data from 15 buoys located throughout the South China Sea(SCS)were used to evaluate the ERA5 wind and wave data.Applicability assessment are beneficial for gaining insight into the reliability of the ERA5 data in the SCS.The bias range between the ERA5 and observed wind-speed data was-0.78-0.99 m/s.The result indicates that,while the ERA5 wind-speed data underestimation was dominate,the overestimation of such data existed as well.Additionally,the ERA5 data underestimated annual maximum wind-speed by up to 38%,with a correlation coefficient>0.87.The bias between the ERA5 and observed significant wave height(SWH)data varied from-0.24 to 0.28 m.And the ERA5 data showed positive SWH bias,which implied a general underestimation at all locations,except those in the Beibu Gulf and centralwestern SCS,where overestimation was observed.Under extreme conditions,annual maximum SWH in the ERA5 data was underestimated by up to 30%.The correlation coefficients between the ERA5 and observed SWH data at all locations were greater than 0.92,except in the central-western SCS(0.84).The bias between the ERA5 and observed mean wave period(MWP)data varied from-0.74 to 0.57 s.The ERA5 data showed negative MWP biases implying a general overestimation at all locations,except for B1(the Beibu Gulf)and B7(the northeastern SCS),where underestimation was observed.The correlation coefficient between the ERA5 and observed MWP data in the Beibu Gulf was the smallest(0.56),and those of other locations fluctuated within a narrow range from 0.82 to 0.90.The intercomparison indicates that during the analyzed time-span,the ERA5 data generally underestimated wind-speed and SWH,but overestimated MWP.Under non-extreme conditions,the ERA5 wind-speed and SWH data can be used with confidence in most regions of the SCS,except in the central-western SCS.
基金The Public Welfare Technical Applied Research Project of Zhejiang Province of China under contract No.2015C31021the National Key Research and Development Program of China under contract No.2016YFC1401605the Scientific Foundation of Zhejiang Ocean University of China
文摘The purpose is to study the accuracy of ocean wave parameters retrieved from C-band VV-polarization Sentinel-1Synthetic Aperture Radar（SAR） images, including both significant wave height（SWH） and mean wave period（MWP）, which are both calculated from a SAR-derived wave spectrum. The wind direction from in situ buoys is used and then the wind speed is retrieved by using a new C-band geophysical model function（GMF） model,denoted as C-SARMOD. Continuously, an algorithm parameterized first-guess spectra method（PFSM） is employed to retrieve the SWH and the MWP by using the SAR-derived wind speed. Forty-five VV-polarization Sentinel-1 SAR images are collected, which cover the in situ buoys around US coastal waters. A total of 52 subscenes are selected from those images. The retrieval results are compared with the measurements from in situ buoys. The comparison performs good for a wind retrieval, showing a 1.6 m/s standard deviation（STD） of the wind speed, while a 0.54 m STD of the SWH and a 2.14 s STD of the MWP are exhibited with an acceptable error.Additional 50 images taken in China＇s seas were also implemented by using the algorithm PFSM, showing a 0.67 m STD of the SWH and a 2.21 s STD of the MWP compared with European Centre for Medium-range Weather Forecasts（ECMWF） reanalysis grids wave data. The results indicate that the algorithm PFSM works for the wave retrieval from VV-polarization Sentinel-1 SAR image through SAR-derived wind speed by using the new GMF C-SARMOD.
文摘目的探讨血栓通注射液联合鼠神经生长因子治疗非动脉炎性前部缺血性视神经病变(AION)的疗效观察。方法选取2013年6月—2015年6月沈阳市第四人民医院眼科收治的非动脉炎性AION患者88例,按治疗方案的差别将患者分为对照组和治疗组,每组各44例。对照组肌肉注射注射用鼠神经生长因子,18μg/次加入到0.9%生理盐水或灭菌注射用水2 m L中溶解,1次/d。治疗组在对照组治疗基础上静脉滴注血栓通注射液,5 m L加入到0.9%生理盐水250 m L,1次/d。两组患者均连续治疗4周。观察两组的临床疗效,同时比较两组视野缺损(MD)、P100波潜伏期、视盘各象限视神经纤维层厚度(ATRNFL)、视力提高行数。结果治疗后,对照组和治疗组的总有效率分别为77.27%、93.18%,两组比较差异有统计学意义(P<0.05)。治疗后,两组患者MD、P100潜伏期较治疗前显著减小,同组治疗前后差异具有统计学意义(P<0.05);且治疗组的改善程度优于对照组,两组比较差异具有统计学意义(P<0.05)。治疗后,两组ATRNFL均较治疗前减小,但治疗后治疗组ATRNFL较对照组高,两组比较差异具有统计学意义(P<0.05);并且治疗后对照组ATRNFL较正常值低。治疗组的视力提高行数高于对照组,两组比较差异具有统计学意义(P<0.05)。结论血栓通注射液联合鼠神经生长因子治疗非动脉炎性AION具有较好的临床疗效,可明显改善视力,有效提高视野,具有一定的临床推广应用价值。
