1999 Vol. 18, No. 4

Display Method:
Articles
Volume and heat transports and material fluxes in the East China Sea during April 1994
Yuan Yaochu, Pan Ziqin, Wang Huiqun, Hu Dunxin, Guan Weibing, Xu Weiyi, Cui Maochang
1999, (4): 449-457.
Abstract:
A modified inverse method is used to compute the volume transport(VT),the heat transport (HT) and the horizontal material fluxes in the East China Sea with data of CTD,TCO2,DOC,POC,etc.obtained in April 1994.In April 1994 VT and HTthrough Section PN in the East China Sea are 30.6×106 m3/s and 2.42×1015 W respectively,and the horizontal fluxes of TCO2,DOC and POC through Section PN are 65×106,2.2×106 and 0.17×106 mol/s respectively.This means that the percentages of fluxes of TCO2,DOC and POC in total C flux are about 96.5%,3.3% and 0.2% respectively.VT and HT through Section S5(near the Tokara Strait) are 26.7×106m3/s and 2.14×1015W respectively,which are about 87% and 88% of VT and HT through Section PN respectively.The horizontal flux of TCO2 through Section S5is 61×106 rnol/s,which is about 93.8% of the flux of TCO2 through Section PN,i.e.,its percentage is close to that of VT and HT of Sections S5 and PN.The horizontal fluxes of DOC and POC through Section S5 are 2.5×106 and 0.08×106 mol/s respectively.The sum of the horizontal influx and outflux of TCO2 through the boundaries of Box-2 is about -2×106 mol/s (outflux),which is about 3% of the flux of TCO2 through Section PN.This value is the same order of magnitude of the vertical flux caused by the downwelling or the upwelling.This means that the horizontal flux of TCO2 must be considered,when the vertical flux of TCO2 is computed,and so are the other material vertical fluxes (DOC,etc.).Finally,the vertical velocity component is computed with a diagnostic model.
Variability of the Kuroshio in the East China Sea in 1995
Liu Yonggang, Yuan Yaochu
1999, (4): 459-475.
Abstract:
A modified inverse method is used to oanpute the Kurnshio in the East China Sea with the CTD and wind data collected by R/V Chofu Maru during four cruises of 1995.The computed results show that:(1) The volume trasport (herafter VT) of the Kuroshio through Section PN is 23.3×106,34.1×106,21.1×106 and 26.7×106 m3/s.respectively.during winter,spring,summer and autumn,ie.,its VT is largcst in spring but smallest in the summes of 1995.However,from the statistical average results [e.g.,Yuan et al.(1993) ],its VT is largest in summer but smallest in autumn.This means that the year 1995 is an ananalous year,which can also be shown from the T-S distributions.The heat transport(hereafter HT) through Section PN is 1.6×1015,2.5×1015,1.7×1015 and 2.1×1015 W,respectively,during winter,spring,summer and autumn.This shows also that the year 1995 is an anomalous year.VT through Section TK (at the Tokara Strait) is also largest in the spring of 1995.(2) There are two current cores at Section PN during winter,spring and summer,and three cores in autumn.(3) The Kuroshio velocitics at Section PN are stronger in spring and autumn than those in the winter and summer of 1995.(4) There are countercurrents under and east of the Kuroshio at Section PN.(5) The average rate of heat transfer in the oomputed area from the ocean to the atrrnsphere is 6.28×103,-0.83×103,-2.09×103 and 2.49×103 J /(cm2·d),respectively,during winter,spring,summer and autumn.
A baroclinic typhoon model with a moving multi-nested grid and variational adjustment initialization Ⅱ. Forecast experiments
Wu Huiding, Yang Xuelian, Bai Shan, Li Guoqing
1999, (4): 477-493.
Abstract:
A 3-dimensional baroclinic typhoon model with a moving multi-nested grid and its initialization are described first.Prediction results are improved by using a simple but effective data assimilation method in which the initial field is adjusted by the sixth hour's typhoon report and the weak-constraint variational principle.Finally some forecyst examples made by this typhoon model are given.
Steady motion and spiral patterns in typhoon
Liu Shikuo, Liang Fuming, Liu Shida, Xin Guojun
1999, (4): 495-504.
Abstract:
By using the equations describing typhoons in the atmosphere,the steady three-dimensional stream field and the corresponding pressure and temperature fields are obtained. The three-dimensional velocity fields construct a nonlinear autonanous system in the physical space.It is shown that the center of typhoon is a local minimum pressure with positive vertical vorticity and horizontal convergence in lower levels and a local marumum pressure with negative vertical vorticity and horizontal divergence in the upper levels. Because there exist two saddle-focus points in the autonornous system,there exist the spiral patterns,in which the winds blow spinally in and out of the center in the lower and upper levels in the Northern Hanisphere and cause the ascending rrotion near the center and descending motion and the edge,respectively.All these are in fair oonfoxmity with the observations.It impVes that the rotation of earth and the visooaity of air play an important role in the spiral structure of typtxbns.
Response of western equatorial Pacific to a westerly wind burst
Chai Fei, Xue Huijie
1999, (4): 505-514.
Abstract:
Atmospheric jets-winds with shear-can induse a vertical oceanic circulation with upwelling and downwelling even over the open ocean in regions where the Coriolis parameter can be regarded as a constant.Winds with no shears that blow parallel to the equator can also induce a vertical oceanic circulation with upwelling and downwelling within an equatorial radius of deforntation.This study concerns the oceanic response to a westerly wind burst,in the form of an atmospheric jet,similar to those that occur over the western equatorial Pacific.It is shown that the shear of the wind,if it is within an equatorial radius of deformation,can alter the vertical circulation substantially,especially if there are westerly and easterly winds near the equator.A commentary on measurements made during a westerly wind burst over the western equatorial Pacific has been given.
Development of acoustic suspended sediment monitor
Zhang Shuying, Li Yunwu, Guo Jijie
1999, (4): 515-521.
Abstract:
An acoustic suspended sediment monitor (ASSM) has been developed for the observation of suspatded sediment ooncanration profiler in water,rmnitoring pollutants in water and for the studies of ooestal sediment trensportatmn and deposition.The determination of the main technical parameters and the methodokogy of resdving the key technique and laboratory calibration are reviewed.The ASSM was applied to observe the suspended sediment in the Changjiang Estuary,whose typical suspended sediment concentration Profilers have been obtained.
Calculation of geoid undulations and gravity anomalies in the Northwest Pacific by using the Topex/Poseidon and Geosat altimeter data
Pan Jiayi, Wang Junqin, Wang Yanfeng, Zhang Xinmei, Yuan Yeli, Zheng Quan'an
1999, (4): 523-533.
Abstract:
The geoid undulations in the Northwest Pacific were calculated by using the Topex/Paseidon and Geoeat altirreter data.Firstly the bias between two types of the altimeter data was removed and the geoid undulations in the Northwest Pacific were acquired by a long wave bias diminishing model with a resolution of 30 km and precision of 14 cm.Then an algorithm of inversion of gravity artarrtalies was derived,and the gravity anomalies in the East China Seawere calculated by using the algorithm and the geoid undulationts.The rms of difference between the in situ measurements and the gravity anomalies from altimeter data was 3.8×10-5 m/s2.A method to calculate the gravity artornalies in a larger area was developed which combined gravity anomalies in four subregions overlapping each other into one data set in a larger region.The error analysys shows that the model and result of the inversion of gravity anomalies were reliable.
In-situ calibration of acoustic measurements of suspended sediment
Guo Jijie, Ren inifa, Li Yunwu
1999, (4): 535-542.
Abstract:
The key to the problem of probing the concentration of suspended sediment in water and its variation with eooustic equipment is how to calibrate the obtained data.Combining the acoustic backscatter intensity data with the real concentration of suspended sediment from water samples collected from the Changjiang Estuary,three in-situ calibration methods for ttansfomting measured sediment are induced.Results show that the discrepancies between calibrated values given by characteristic time calibration and real ones are less than the values given by single shot method,and the statistical error is 20% approximately.The calibration on characteristic times is practical and simpler than simultaneous calibration.
Characteristics of metals in atmosphere over the western Taiwan Strait Ⅱ. Sources and fluxes
Chen Liqi, Wang Zhihong, Yang Xulin, Yu Qun
1999, (4): 543-554.
Abstract:
Atmospheric metals over the western Taiwan Strait are studied and their sources are identified.Al and Fe are mainly from crustal soil.A little amount of Fe is from pollution.Pb and Cd are mainly from pollution sources.A little amount of Pb is from crustal soil and recycled sea spray.Na is mostly from seawater and a little amount of Na is from crustal soil or secondary aerosol particles.Cu is mainly from crustal soil,partly from pollutants,and a little amount from recycled sea spray.Comparing the total inputs of the atmospheric deposition of the metals to the Taiwan Strait waters with the inputs from the rivers shows that the input of Cu from the atmosphere is lower than that from the rivers,and the input of Pb is higher than that from the rivers;the input of Cd is a little higher than that from the nvers.
Isolation and identification of alginate-degrading bacteria and formation of alginase
Han Baeqin, Dai Jixun, Wang Hai
1999, (4): 555-561.
Abstract:
Five strains of alginate-degrading bacteria were isolated from the decaying parts of Laminaria japonica and Undaria pinnatifrda and identified as Alteromrnas esppjiana (Strain A101,A102,A103,A105)and Al-teromonas macleorlii(Strain A104).When incubated at 25℃ for 144 h in the liquid medium which contained 0.5% peptone,0.3%w-0.6% sodium alginate,0.1% yeast extract,3% NaCl,pH 7.5,the strain A102 produced the highest amount of aginase.
Ecological characteristics of phytoplankton community from eutrophic waters in the Maluan Bay
Yang Qingliang, Chen Qihuan, Lin Jinmei, Lin Gengrning, Chen Xingqun
1999, (4): 563-580.
Abstract:
The present study is based on the analysis ohthe data collected in 10 cruises during the periods of 2 surveys (from May 1992 to January 1993 and from August 1993 to May 1994).The resulu show that the number of phytoplanktat species in highly eutrophic waters of the Maluan Bay is low,only 6-35 species from each cruise and 66 species in total from the 2 surveys.The phytoplankton abundance is high.The mean cell densities of phytoplankton from the net samples were 21 386×104cells/m3 for the first survey and 110 136×104 cells/m3 for the second survey,that from the water samples was 1 150.7 cells/cm3.The mean concentration of chlorophyll a reached 6.67 mg/m3.Both the species diversity (H') and evenness (J) were low,only 0.78 and 0.28,respectively.The temporal and spatial fluctuation of the cell density of phytoplankton was quite significant,caused mainly by contribution of pennate diatom Nitzschia delicatissima that often abudantly occurred in a closed waters rich in organic matter and could be taken as an mologic indicator of highly eutrophic harbour.The existence of good correlation between the cell density of Nitzxhia delicatissima and some environmental variables (e.g.PO4-3-P and COD,etc.),and the heterotrophic tendancy of this species are discussed,too.
Study on fish community structure in the Zhujiang Estuary and its adjacent waters
Zhan Haigang
1999, (4): 581-589.
Abstract:
Based on data of demersal trawl samples from 1987 to 1988 in the Zhujiang Estuary and its adjacent watens,relationships between fish community and environmental factors are studied by using classification,MDS ordination and several community parameters.The results show that the distribution of fish species is zoned by salinity and divided into three types.The freshwater community which is restricted in the Lianhua Hill-Humen waterway is simple and stable,the coastal community which lives in the shallow waters is canplex,and the estuary community which is identified in the Lingdingyang area and affected by physical and eool by cal processes more greatly has obvious seasonal variations.
Detection of prawn white spot baculovirus by polymerase chain reaction
Wang Wei, He Jun, Yang Feng, Wu Guikai, Xu Xun
1999, (4): 591-598.
Abstract: