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Characteristics of climate change in the “significant impact zone” affected by aerosols over eastern China in warm seasons

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Science China earth sciences 2008年第5期51卷 730-739页

作者： SHI XiaoHui1, XU XiangDe1, XIE LiAn2 1 state Key Laboratory of Severe Weather, Chinese Academy of Meteorological sciences, Beijing 100081, China 2 department of marine, earth and atmospheric sciences, north carolina state university, raleigh nc2.695-82.8, usa state Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China department of marine Earth and Atmospheric Sciences North Carolina State University Raleigh NC 27695-8208 USA

Through analysis of the distribution pattern and changing characteristics of atmospheric aerosols over the East Asia region during warm seasons in recent 20 a and beyond as well as their possible interac- tive relationship with a variety of meteorological elements, it is found that the high-value zone of aerosol optical depth derived from the Total Ozone Mapping Spectrometer (TOMS), its significant negative correlation zones in terms of sunshine duration (SD) and surface air temperature (SAT) and its significant positive correlation zones with low-level cloud amount (LCC) are co-located in the South China region during warm periods. Based on this finding, the region is referred to as a "significant impact zone" (SI zone) affected by aerosols. Then, a comparative analysis is made on variation differ- ences of observed SAT, SD and LCC, etc. in different regions. It is also found that the LCC is increased and the SD is decreased within the "SI zone" over eastern China during the warm season. These characteristics are more evident than those beyond the zone, while the warming trend within the zone is evidently weaker than that outside it. Studies show that since recent 20 a, under the influence of aerosols, the LCC tend to increase substantially with a clear decrease of SD and an unnoticeable warming trend within the "SI zone". Comparing with the climate change beyond the zone, the difference is significant. Therefore, the effects of atmospheric aerosols on climate is possibly one of the contri- butions to the difference of climate change existed between the southern and northern parts of the Eastern China during a warm season.

关键词： warm season significant impact zone of aerosols climate change

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Effects of wind waves of the Pacific westerly on the eastern Pacific wave transport

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Acta Oceanologica Sinica 2009年第1期28卷 83-88页

作者： DENG Zeng＇ an WU Kejian ZHAO Dongliang YU Ting Physical Oceanography Laboratory Ocean University of China Qingdao Shandong 266100 China marine earth ＆ atmospheric sciences North Carolina State University Raleigh NC 27695 USA

There exists a tongue-shaped swell-dominance pool known as Swell Pool（SP） in the Eastern Pacific *** monthly-mean wave transports（WT） for each month of 2000 is computed using the wave products of ECMWF reanalysis *** comparing the 2000 monthly-mean WT and monthly-mean wind field from QUICKSCAT,large differences are found between the wave transport direction and the wind direction over the Eastern *** may serve as an evidence for the existence of the SP in this *** work done in this study indicates that the sources of swell in the Tropical Eastern Pacific（TEP） are in the westerly regions of the Southern and northern Pacific.

关键词： swell pool wave transport Eastern Pacific Westerly

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Paleoenvironmental records from the northern South China Sea since the Last Glacial Maximum

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Acta Oceanologica Sinica 2010年第3期29卷 46-62页

作者： GE Qian CHU Fengyou XUE Zuo LIU J Paul DU Yuansheng FANG Yinxia Faculty of earth sciences China University of Geosciences Wuhan 430074 China Key Laboratory of Submarine Geosciences State Ocean Administration Hangzhou 310012 China department of marine Earth and Atmospheric Sciences North Carolina State University Raleigh NC 27695 USA

Core ZHS-176 contains the paleoenvironmental records from the northern South China Sea （NSCS） since the Last Glacial Maximum （LGM）. A coupled approach based on clay mineral assemblages, planktonic foraminiferal oxygen and carbon isotopes, and calcium carbonate content is used to trace the sources of the fine-grained sediment and to investigate the paleoenviornmental evolution in this area. Clay mineral assemblages are dominated by illite （average about 39%） and chlorite （about 27%）, which comes mainly from Taiwan and the East China Sea. Kaolinite, which accounts for about 13%, comes mainly from the Zhujiang （Pearl） River, and Luzon Island is the main source for smectite （about 21%）. The planktonic foraminiferal oxygen isotopic oscillations during the last glacial period are coeval with climate variations recorded in the Greenland ice core and Western Pacific sediment. These variations include the LGM, Heinrich event 1, Bφlling-Allerφd （B/A）, and Younger Dryas. For the Holocene, three periods of strong precipitation （S1-S3） and three periods of weak precipitation （W1-W3） are identified. The oxygen isotopic record exhibits corre-lation with climate records from distant regions, including the high-latitude northern Hemisphere, providing evidence for global tele-connection among regional climate. A brief, negative planktonic foraminiferal carbon isotopic excursion during B/A reflects increased methane released from marine gas hydrate due to the rapid warming of the water. By comparing calcium carbonate content curves of the core ZHS-176 with these of other five boreholes lying above the lysocline, a remarkable low calcium carbonate event is found during the early Holocene in NSCS.

关键词： clay mineral oxygen and carbon isotopes calcium carbonate content South China Sea paleoenvironmental evolution

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Effects of salinity on methane gas hydrate system

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Science China earth sciences 2007年第11期50卷 1733-1745页

作者： YANG DingHui1 & XU WenYue2 1 department of Mathematical sciences, Tsinghua university, Beijing 100084, China 2 School of earth & atmospheric sciences, Georgia Institute of Technology, Atlanta, GA 30332, usa 1. department of Mathematical sciences Tsinghua University Beijing 100084 China 2. School of earth & atmospheric sciences Georgia Institute of Technology Atlanta GA 30332 USA

Using an approximately analytical formation, we extend the steady state model of the pure methane hydrate system to include the salinity based on the dynamic model of the methane hydrate system. The top and bottom boundaries of the methane hydrate stability zone (MHSZ) and the actual methane hy-drate zone (MHZ), and the top of free gas occurrence are determined by using numerical methods and the new steady state model developed in this paper. Numerical results show that the MHZ thickness becomes thinner with increasing the salinity, and the stability is lowered and the base of the MHSZ is shifted toward the seafloor in the presence of salts. As a result, the thickness of actual hydrate occur-rence becomes thinner compared with that of the pure water case. On the other hand, since lower solubility reduces the amount of gas needed to form methane hydrate, the existence of salts in sea-water can actually promote methane gas hydrate formation in the hydrate stability zone. Numerical modeling also demonstrates that for the salt-water case the presence of methane within the field of methane hydrate stability is not sufficient to ensure the occurrence of gas hydrate, which can only form when the methane concentration dissolved in solution with salts exceeds the local methane solubility in salt water and if the methane flux exceeds a critical value corresponding to the rate of diffusive methane transport. In order to maintain gas hydrate or to form methane gas hydrate in marine sedi-ments, a persistent supplied methane probably from biogenic or thermogenic processes, is required to overcome losses due to diffusion and advection.

关键词： methane gas hydrate,solubility,stability of hydrate,salinity,phase equilibrium

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Heat treatment of novel low-carbon multi-alloyed anti-wear marine steel

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Progress in Natural Science:Materials International 2011年第3期21卷 254-261页

作者： Jing-hua JIANG~(1,2),Qiu-yue WANG~1,Ai-bin MA~(1,2),Jun SHI~1,Liu-yan ZHANG~1, Hui-dong YANG~(2,3),Fu-min LU~2,Qi ZHOU~2 1.National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Hohai university,Nanjing 210098,China 2.College of Mechanics and Materials,Hohai university,Nanjing 210098,China 3.department of Mechanical and Aerospace Engineering,north carolina state university, raleigh,north carolina 2.695-7919,usa [a] National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Hohai University Nanjing 210098 China [b] College of Mechanics and Materials Hohai University Nanjing 210098 China [c] department of Mechanical and Aerospace Engineering North Carolina State University Raleigh North Carolina 27695-7919 USA

A low-carbon anti-wear steel,multi-alloyed with Si-Cr-Mn-Al-Ni-Mo-（Nb,RE）,was designed for vane pumps of ships. The novel cast steel after various heat treatments was characterized by microstructure observations and mechanical properties measurement in order to achieve an optimal process correlated with good abrasive resistance for a long marine *** scanning calorimetry and hardness analyses deduced a complete austenitizing temperature of 1 000℃,based on the alloying element homogenization and defective structure elimination without grain *** optimal austempering process（austenitized at 1 000℃,quick cooled for holding at 350℃for 1.5 h and then air-cooled to room temperature） produced a uniform mixture structure of fine carbide-free aciculate bainites and few lath martensites,resulting in the tensile strength increase of 34%and impact toughness increase of 50%compared with that of the as-cast *** abrasive wheel tests show that the austempered steel has good wear resistance with a mass-loss rate of 170 mg/（km·cm2） under applied load of 70 N in acidic *** new grade steel （containing anti-corrosion elements of Cr and rare earth） can find wide application in marine engineering,with further enhanced comprehensive properties via melting process improvement.

关键词： abrasive resistance carbide-free bainite marine steel mechanical performance heat treatment

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Spatial character of the gaseous and particulate state compound correlation of urban atmospheric pollution in winter and summer

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Science China earth sciences 2005年第S2期48卷 64-79页

作者： XU Xiangde, SHI Xiaohui, XIE Lian, DING Guoan, MIAO Qiuju, MA Jianzhong & ZHENG Xiangdong state Key Laboratory of Severe Weather, Chinese Academy of Meteorological sciences, Beijing 100081, China Nanjing university of Information Science and Technology, Nanjing 210044, China department of marine, earth and atmospheric sciences, north carolina state university, raleigh, nc2.695-82.8, usa National Climate Center, China Meteorological Administration, Beijing 100081, China state Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China state Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China Nanjing university of Information Science and Technology Nanjing 210044 China department of marine Earth and Atmospheric Sciences North Carolina State University Raleigh NC27695-8208 USA National Climate Center China Meteorological Administration Beijing 100081 China

The spatial/temporal variation information of atmospheric dynamic-chemical processes at observation site points of the "canopy" boundary of Beijing urban building ensemble and over urban area "surface", as well as the seasonal correlation structure of the gaseous and par-ticulate states of urban atmospheric pollution (UAP) and its seasonal conversion feature at observation points are investigated, using the comprehensive observation data of the Beijing City Air Pollution Observation Experiment (BECAPEX) in winter and summer 2003 with a "point-surface" combined research approach. By using "one dimension spatial empirical orthogonal function (EOF)" principal component analysis (PCA) mode, the seasonal change of gaseous and particulate states of atmospheric aerosols and the association feature of pollutant species under the background of the complicated structure of urban boundary layer (UBL) are analyzed. The comprehensive analyses of the principal components of particle concentrations, gaseous pollutant species, and meteorological conditions reveal the seasonal changes of the complex constituent and structure features of the gaseous and particulate states of UAP to further trace the impact feature of urban aerosol pollution surface sources and the seasonal difference of the component structure of UAP. Research results suggest that in the temporal evolution of the gaseous and particulate states of winter/summer UAP, NOx, CO, and SO2 showed an "in-phase" evolution feature, however, O3 showed an "inverse-phase" relation with other species, all possessing distinctive dependent feature. On the whole, summer concentrations of gaseous pollutants CO, SO2, and NOx were obviously lower than winter ones, especially, the reduction in CO concentration was most distinctive, and ones in SO2 and NOx were next. However, the summer O3 concentration was more than twice winter one. Winter/summer differences in PM10 and PM2.5 particle concentrations were relatively not obvious, which ind

关键词： aerosol correlation structure principal component analysis.

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PROPAGATION OF LONG-LIVED ANTICYCLONIC ROSSBY EDDIES OVER AN ISOLATED TOPOGRAPHY AND THEIR MERGING

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Journal of Hydrodynamics 2001年第3期13卷 34-45页

作者： Luo, De-Hai Lu, Yan Ocean Univ. of Qingdao Qingdao 266003 China

In a barotropic model the propagation of long-lived anticyclonic Gaussian eddies larger than the radius of deformation over a Gaussian-shaped topography and the merging of the two anticyclonic eddies are investigated by solving the generalized Flierl-Yamagata equation. It is shown that whether or not the basic flow is present, the isolated topography seems to encourage the amplification of an anticyclonic eddy and its southwest movement around the hill In the absence of both the westward flow and the topography, two anticyclonic eddies of identical sizes and amplitudes can merge. However, either the including of the topography or the westward basic flow can make them not merge. In the presence of both, the eddies can merge, but this merging depends on whether the parameter condition is appropriate or not. Therefore, it can be concluded that the topographic forcing might be a possible mechanism for the merging of two anticyclonic eddies.

关键词： Amplification Equations of motion Merging Surface topography Two dimensional

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Impact of Global Change on Biological Processes in the Soil: Implications for Agroecosystem Management

Impact of Global Change on Biological Processes in the Soil:...

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’2003中国作物学会学术年会

作者： Wei-Jian ZHANG 1,2 and Shui-Jin HU 2 ( 1 department of Agronomy, Nanjing Agricultural university, Nanjing 210095, China 2 College of Agriculture and Life sciences, north carolina state university, raleigh, nc 27607, usa)

The earth is undergoing rapid environmental changes due to human activities. Three components of the ongoing global change, elevated atmospheric CO 2, N deposition and global warming, may significant

关键词： global change elevated CO 2 nitrogen deposition global warming decomposition N mineralization food web interactions

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Three-dimensional structure of a low salinity tongue in the southern Taiwan Strait observed in the summer of 2005

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Acta Oceanologica Sinica 2009年第4期28卷 1-7页

作者： HONG Huasheng ZHENG Quanan HU Jianyu CHEN Zhaozhang LI Chunyan JIANG Yuwu WAN Zhenwen state Key Laboratory of marine Environmental Science College of Oceanography and Environmental Science Xiamen University Xiamen 361005 China department of atmospheric and Oceanic Science University of Maryland College Park MD 20742 USA department of Oceanography and Coastal sciences Coastal Sciences School of the Coast and Environment Louisiana State University Baton Rouge LA 70803 USA

Cruise observations with CTD （conductivity-temperature-depth） profiler were carried out in the southern Taiwan Strait in the summer of 2005. Using the cruise data, two-dimensional maps of salinity and temperature distributions at depths of 5, 10, 15, 20, and 30 m were generated. The maps show a low salinity tongue sandwiched by low temperature and high salinity waters on the shallow water side and high temperature and high salinity waters on the deep water side. The further analysis indicates that the low salinity water has a nature of river-diluted water. A possible source of the diluted water is the Zhujiang （Pearl） Estuary. Meanwhile, the summer monsoon is judged as a possible driving force for this northeastward jet-like current. The coastal upwelling and the South China Sea Warm Current confine the low salinity water to flow along the central line of the strait. Previous investigations and a numerical model are used to verify that the upstream of the low salinity current is the Zhujiang Estuary. Thus, the low salinity tongue is produced by four major elements： Zhujinag Estuary diluted water, monsoon wind driving, coastal upwelling and South China Sea Warm Current modifications.

关键词： Taiwan Strait low salinity tongue river diluted water cruise measurement

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Dynamical analysis of mesoscale eddy-induced ocean internal waves using linear theories

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Acta Oceanologica Sinica 2008年第3期27卷 60-69页

作者： XU Qing ZHENG Quanan LIN Hui LIU Yuguang SONG Y Tony YUAN Yeli Institute of Space and earth Information Science The Chinese University of Hong Kong Hong Kong China department of atmospheric and Oceanic Science University of Maryland College Park Maryland USA Physical Oceanography Laboratory Ocean University of China Qingdao 266100 China Jet Propulsion Laboratory California Institute of Technology Pasadena California USA Key Laboratory for marine Science and Numerical Modeling of state Oceanic Administration First Institute of Oceanography State Oceanic Administration Qingdao 266061 China

This study aims to explore generation mechanisms of the ocean internal wave using the dynamical analysis methods based on linear theories. Historical cruise measurements and recent synthetic aperture radar （SAR） observations of mesoscale eddies with diameter of several tens of kilometers to hundreds of kilometers show that the internal wave packets with wavelength of hundreds of meters to kilometer exist inside the mesoscale eddies. This coexistence phenomenon and inherent links between the two different scale processes are revealed in the solutions of governing equations and boundary conditions for the internal wave disturbance with a horizontally slowly variable amplitude in a cylindrical coordinate system. The theoretical solutions indicate that the instability of eddy current field provides the dynamical mechanism to internal wave generation. The derived dispersion relation indicates that the internal wave propagation is modified by the eddy current field structure. The energy equation of the internal waves clearly shows the internal wave energy increment comes from the eddy. The theoretical models are used to explain the observation of the mesoscale eddy-induced internal waves off the Norwegian coast. The two-dimensional waveform solution of the anticyclonic eddy-induced internal wave packet appears as ring-shaped curves, which contains the typical features of eddy stream lines. The comparison of theoretical solutions to the structure of the internal wave packets on SAR image shows a good agreement on the major features.

关键词： ocean internal waves mesoscale eddy current field instability SAR image

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