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The Influence of Wind Speed and Sea States on Whitecap Coverage

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Journal of Ocean University of China 2019年第2期18卷 282-292页

作者： JIA Nan zhao dongliang College of Oceanic and Atmospheric Sciences Ocean University of China Physical Oceanography Laboratory Ocean University of China

Callaghan and White(2009) put forward the automated whitecap extraction(AWE) technique to determine the whitecap coverage(W). An improved AWE was used to analyze images collected in the South China Sea during 2012 and 2013 and in western Pacific during 2015 to determine W. The influences of meteorological and oceanographic factors on whitecap coverage were investigated in this study. It is found that W increases with wind speed. Scale factor and exponent of parameterization for W(U10) vary greatly in different models. Overall, there is a larger scatter of W at low wind speed than at high wind speed. W decreases with the increasing of wave age. Compared with wind speed, the scatter of W is smaller with wave age, which means the impact of wave age on the whitecap coverage is more robust under various environmental conditions. There is no significant dependence on SST and whitecap coverage seems to weakly decrease with SST. W decreases with the atmospheric stability. Relationship between W and wind speed change when swells are dominant. Swell can suppress wave breaking and decrease W. The effect is independent of the deflection angle between wind wave and swell.

关键词： whitecap coverage AWE wave age SST thermal stability swell

On the Study of Wave Propagation and Distribution in the Global Ocean

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Journal of Ocean University of China 2019年第4期18卷 803-811页

作者： LIU Min zhao dongliang Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology Ocean University of China Qingdao 266100 China Ocean College Hebei Agricultural University Qinhuangdao 066000 China

Based on the simulation with SWAN wave model and data of ERA-Interim from 1979 to 2016, how the waves propagate globally and why swell pools distribute in the eastern ocean were investigated in this study. The simulation results show that waves from North Pacific and North Atlantic mainly propagate southeastward or southward and swells generated in Southern Ocean spread northeastward. The waves from high latitude regions spread along the east coast and encounter in the tropical Pacific and Atlantic to form swell fronts around equator and then turn eastward. As the weak wind field with numerous swell inflows, swell pools are gener- ally located on the eastern side of the ocean basin, where the swell index S are greater than 0.9 calculated using ERA-20C data for the period of 1981 2010. Another remarkable feature is that swell pools move southward and split into two parts in winter, while they move northward and merge together in summer.

关键词： wave propagation SWAN swell front swell pool wave energy density

Effects of substrate temperature and annealing treatment on the microstructure and magnetic characteristics of TbDyFe films

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Rare Metals 2007年第5期26卷 408-413页

作者： DU zhaofu WANG Lei zhao dongliang Functional Materials Research Institute Central Iron and Steel Research Institute Beijing 100081 China

A series of TbDyFe films were prepared by DC magnetron sputtering. The effects of substrate temperature and annealing temperature on the phase structure and the magnetic properties of the sample films were investigated. The an-nealing treatment has a significant influence on the microstructure and the magnetic properties of the sample. The results obtained by XRD indicate that the films deposited at a temperature lower than 525℃ are amorphous and have an easy magnetization direction perpendicular to the film plane. An RFe2 phase is formed in the sample annealed at 550℃ and the residual phases observed are Fe and rare earth oxide. The magnetic properties Hc and Mr/Ms of the film annealed at 550℃ obtain the maximum values,for which the formation of the RFe2 phase is mainly responsible. An annealing treatment leads to a rotation of the sample’s easy axis from being parallel to the film surface to becoming vertical.

关键词： TbDyFe thin film amorphous substrate temperature annealing temperature

A numerical study of Stokes drift and thermal effects on the oceanic mixed layer

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Acta Oceanologica Sinica 2020年第5期39卷 35-45页

作者： Xuewei Li dongliang zhao Zhongshui Zou Physical Oceanography Laboratory Ocean University of ChinaQingdao 266100China Ocean College Zhejiang UniversityZhoushan 316021China

This study explores the influence of Stokes drift and the thermal effects on the upper ocean bias which occurs in the summer with overestimated sea surface temperature(SST)and shallower mixed layer depth(MLD)using Mellor-Yamada turbulence closure *** upper ocean thermal structures through Princeton ocean model are examined by experiments in the cases of idealized forcing and real observational *** results suggest that Stokes drift can generally enhance turbulence kinetic energy and deepen MLD either in summer or in *** effect will improve the simulation results in summer,but it will lead to much deeper MLD in winter compared to observational *** is found that MLD can be correctly simulated by combining Stokes drift and the thermal effects of the cool skin layer and diurnal warm layer on the upper mixing *** the case of high shortwave radiation and weak wind speed,which usually occurs in summer,the heat absorbed from sun is blocked in the warm layer and prevented from being transferred *** a result,the thermal effects in summer nearly has no influence on dynamic effect of Stokes drift that leads to deepening ***,when the stratification is weak in winter,the thermal effects will counteract the dynamic effect of Stokes drift through enhancing the strength of stratification and suppress mixing ***,the dynamic and thermal effects should be considered simultaneously in order to correctly simulate upper ocean thermal structures in both summer and winter.

关键词： mixed layer cool skin layer diurnal warm layer Stokes drift

Reconstructing the upper ocean thermal profiles using one-dimensional numerical model

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Acta Oceanologica Sinica 2012年第2期31卷 9-15页

作者： LIN Zhenhua zhao dongliang SONG Jinbao Institute of Oceanology Chinese Academy of SciencesQingdao 266071China Key Laboratory of Chinese Academy of Sciences for Ocean Circulation and Waves(KLOCAW) Institute of OceanologyChinese Academy of SciencesQingdao 266071China College of Physical and Environment Oceanography Ocean University of ChinaQingdao 266100China

The observation data for 5 d at a station in the South China Sea is presented. After brief anMysis of the wind speed, air temperature from the ship-borne meteorological instruments and temperature and salinity profiles from the CTD （conductivity, temperature, depth recorder） data, the authors find that the CTD casts are too sparse for us to understand the diurnal evolution of the thermal structure in the upper ocean. A one-dimensional （1D） numericM code based on Mellor-Yamada turbulence closure model is used to reconstruct the upper ocean thermal structure, utilizing the atmospheric forcing data from ship-borne weather station. The simulation results show good agreement with the observational data; the significance of breaking waves is also briefly discussed. The evolution of turbulence kinetic energy （TKE） and the contribution from shear production and buoy- ancy production are discussed respectively. Finally, several possible factors which might influence the numerical results are briefly analyzed.

关键词： thermal profile one-dimensional numerical model upper ocean turbulence kinetic energy

The comparison of altimeter retrieval algorithms of the wind speed and the wave period

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Acta Oceanologica Sinica 2012年第3期31卷 1-9页

作者： zhao dongliang LI Shuiqing SONG Chaoyang Physical Oceanography Laboratory Ocean University of ChinaQingdao 266100China

With the launch of altimeter,much effort has been made to develop algorithms on the wind speed and the wave *** using a large data set of collocated altimeter and buoy measurements,the typical wind speed and wave period algorithms are *** on theoretical argument and the concept of wave age,a semi-empirical algorithm for the wave period is also proposed,which has the wave-period dimension,and explicitly demonstrates the relationships between the wave period and the other *** is found that Ku and C band data should be applied simultaneously in order to improve either wind speed or wave period *** dual-band algorithms proposed by Chen et al.(2002) for the wind speed and Quilfen et al.(2004) for the wave period perform best in terms of a root mean square error in the practical applications.

关键词： altimeter wind speed wave period wave age significant wave height

Derivation of a wave-state-dependent sea spray generation function and its application in estimating sea spray heat flux

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Science China Earth Sciences 2015年第10期58卷 1862-1871页

作者： LIU Bin GUAN ChangLong XIE LiAn zhao dongliang Physical Oceanography Laboratory Ocean University of China Department of Marine Earth and Atmospheric Sciences North Carolina State University

A sea spray generation function(SSGF)for bubble-derived droplets that takes into account the impact of wave state on whitecap coverage was presented in this *** combining the new SSGF with a previous wave-state-dependent SSGF for spume droplets,an SSGF applicable to both bubble-derived and spume droplets that includes the impacts of wave state was *** produced SSGF varies with surface wind as well as with wave *** sea surface wind increases,more sea spray droplets are produced,resulting in larger SSGFs and volume ***,under the same wind conditions,the SSGF is mediated by wave state,with larger SSGFs corresponding to older waves and larger windsea Reynolds *** impact of wave state on sea spray heat flux was then estimated by applying this SSGF while considering the thermodynamic feedback *** given atmospheric and oceanic conditions,the estimated sea spray heat flux increases with wind speed,wave age,and windsea Reynolds number.

关键词： wave state sea spray sea spray generation function air-sea heat flux

Particulate matter emission by an isolated rotating wheel

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Building Simulation 2021年第4期14卷 1163-1173页

作者： Jinwei Song Hua Qian dongliang zhao Weixue Jiang Xiaohong Zheng School of Energy and Environment Southeast UniversityNanjingChina Engineering Research Center of Building Equipment Energyand EnvironmentMinistry of EducationBeijingChina College of Electrical Energy and Power EngineeringYangzhou UniversityYangzhouChina Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology School of Energy and EnvironmentSoutheast UniversityNanjing210096China

Particulate matter emission from rotating wheels, which imparts a force to the contact surface and causes strong air currents, is one of the important pollutant sources on the road. This study investigates the particulate matter emission by measuring mass and size distributions of particulate matter near an isolated rotating wheel in a deliberately designed setup. Five rotating speeds from 0.7 m/s to 1.5 m/s are conducted to test its impact on the emission of particulate matter. Mass of particulate matter is measured at twenty-six sampling points around the rotating wheel under different experimental conditions. Experimental results show that the farther away from the wheel, the less of particulate matters deposited on the sampling points in general. Moreover, the emission factor increases from 0.12 g/vkt to 0.24 g/vkt when the rotating speed of the wheel increases from 0.7 m/s to 1.5 m/s. The number and proportion of PM2.5 and PM10 on different sampling points are also measured. The results show that the position of the highest number of PM2.5 and PM10 tends to move to a further and higher sampling point with the increasing of the speed. Moreover, the number proportions of PM2.5 and PM10 on the sampling points range from 19% to 97% and 61% to 100% at different speeds, respectively. This study is believed to be helpful to estimate particulate matter emission and make effective control strategies on targeted pollution.

关键词： particulate matter emission rotating wheel speed

Influence of Qinghai-Xizang Plateau snow cover on interannual variability of Western North Pacific tropical cyclone tracks

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Journal of Oceanology and Limnology 2023年第6期41卷 2060-2076页

作者： zhaohua WANG dongliang zhao Kejian WU Lian XIE Ocean University of China Qingdao 266100China Department of Marine Earth and Atmospheric SciencesNorth Carolina State UniversityBox 8208RaleighNC 27695USA

Track density function(TDF)was computed for all Western North Pacific tropical cyclones(WNP TCs)tracks from 1950 to 2018,and the TDFs were further investigated using principal component analysis(PCA)to analyze their inter-annual spatial and temporal ***,the relationships between each empirical orthogonal function(EOF)mode and the typhoon count,typhoon landfall count,track pattern,and the Qinghai-Xizang Plateau snow cover(QXPSC)were examined,and the possible physical mechanisms implied by the statistical relationship were *** results show the QXPSC significantly affected the surface-atmosphere heat exchange through snow cover(SC)level,then changed the East Asian summer monsoon regional circulation pattern,influenced the subtropical high-pressure system strength and location,and ultimately affected the WNP TCs track patterns and thus changed their landfall locations.

关键词： tropical cyclone Qinghai-Xizang Plateau snow cover track pattern landfall location