1999 Vol. 18, No. 1

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Articles
Variability of the Kuroshio in the East China Sea in 1992
Liu Yonggang, Yuan Yaochu
1999, (1): 1-15.
Abstract:
Based on the hydrogtaphic data of the four cruises in 1992, a modified inverse method is used to compute the velocity, volume and heat transports of the Kuroshio in the East China Sea. The computed results show that:(1) There are two current cores of the Kuroshio at Section PN in spring and autumn, but one core in winter and summer. The main mre always lies over the shelf break. The Kuroshio is strongest in spring, secondary in winter and summer and weakest in autumn. There are also rnuntercurrents under and east of the Kuroshio at Section PN. (2) There are two current cores of the Kurashio at Section TK in winter the southern part and the deep layer of the Tokara Strait three cores in spring and summer. Countercurrents exist in (3) The Tsushima Warm Current (TSWC) at Section A is strongest in autumn and weakest in winter, and is stronger than the Huanghai Warm Current which lies to the west of the TSWC. (4) The net northeastward volume transport (hereafter VT) through Section PN is largest in summer and smallest in autumn with an average of 28.0×106m3/s in the four cruises of 1992.The net eastward VT at Section TK is also largest in summer. The net northward VT at Section A is largest in autumn. (5) The average heat transport through Section PN during the (our cruises is 2.03×1015 W, and that through Section TK is 2.00×1015 W during the three cruises. (6) In the computation area, heat transfer is from the ocean to the atmosphere during winter, spring and autumn, but from the atmosphere to the ocean in summer. The average rate of heat transfer is largest in winter, but smallest in summer.
Variability of the Kuroshio in the East China Sea in 1993 and 1994
Liu Yonggang, Yuan Yaochu
1999, (1): 17-36.
Abstract:
Abstract-Based on the hydrographic data obtained by the R/V Chofu Maru of eight cruises of 1993-1994, a modified inverse method is used to compute the velocity, volume and heat transports of the Kuroshio in the East China Sea. The calculated results show that:(1) At Section PN, there are two current cores of the Kuroshio in autumn, one of two cores in other seasons. The main cores always lie over the shelf break. Countercurrents always exist east of and in the deep layer under the Kuroshio. (2) At Section TK, the velocity distribution is more complicated, and it may have one, two or three current cores of the Kuroshio. The current cores often appear in the middle and northern parts of the Tokara Strait. There are westward countercurrents in the southern end and deep layer of the strait, and the countercurrent in the southern end of the strait is the strongest in autumn. (3) At Section A, the Tsushima Warm Current (hereafter TSWC) mre lies in the shelf break area, and its Vmax varies between 26-46 cm/s. The Huanghai Warm Current (hereafter HWC) lies to the west of the TSWC, and it is weaker.
A preliminary study on the intermediate water masses in the tropical West Pacific
Wu Risheng, Li Li
1999, (1): 37-48.
Abstract:
Based on the CTD data of China's first WOCE cruise in winter of 1991, and those of the first and second Chinese TOGA cruises in the winters of 1985 and 1986, we apply the classical method of T-S diagram analysis to identify intermediate water masses in the tropical West Pacific and study their distribution feature. Results of these analyses show that there are mainly two kinds of intermediate water masses,namely, the South Pacific Intermediate Water (SPIW) and the North Pacific Intermediate Water (NPIW) in the tropical West Pacific. The NPIW extends north to south with its southern boundary generally at about 8°N. However, it is westwards intensified near the coast of Mindanao Island where it extends further south to about 5°N with more distinctive characteristics of low salinity and temperature. The SPIW extends from south to north with its northern boundary at about 12°N. In the tonal area between 0° and 4°N various intermediate waters interact. The analysis also shows the existence of interannual variations of NPIW in the tropical West Pacific.
Anomalous eastward displacement of the tropical western Pacific warm pool and warming of the tropical eastern Pacific
Long Baosen, Li Bocheng, Zou Emei
1999, (1): 49-58.
Abstract:
Based on the data from the Climate Diagnostics Bulletin, Oceanographic Monthly Summary, UH Sea Level Center and TOGA-COARE IOP, the response of warm pool in the tropical western Pacific and the tropical eastern Pacific SST to the anomalous wind field during 1992/1993 El Niño has been analyzed. The results show that the eastward transport of warm water of the tropical western Pacific due to the westerly wind burst leads not only to a drop of sea level but also to a raise of thermocline in the tropical western Pacific. Consequently the heat content in upper layer water decreases especially in the thermocline. Contrary to this, the positive anomalies of heat content and thermocline depth appear in the tropical eastern Pacific. The positive anomalies in the eastern Pacific lag the negative ones in the western Pacific by two months; The anomalous eastward shift of warm pool (28℃ isotherm) is a direct respouse of ocean current to westerly wind anomalies in low-level atmosphere; quantitative calculations show that the thermal advection caused by anomalous ocean current is the main force of anomalous eastward displacement of the warm pool (28℃ isotherm) and the one of main causes for anomalous warming of the tropical eastern Pacific.
A laboratory study of directional spectra with maximum likelihood method-Ⅰ Developing wind wave
Zhao Dongliang, Masuda Akira, Wen Shengchang, Guan Changlong
1999, (1): 59-74.
Abstract:
measurements by a circular array consisting of 18 wave gauges in a large wave tank, directional spectra of wind-generated waves in deep water are systematically determined by using maximum likelihood method The investigations reveal that the angular spreading of the wave energy is consistent with cos2s(θ/2) proposed by Longuet-Higgins et al.(1963, Ocean Wave Spectra, 111-136), if the bimodal distributions of wave energy are not taken into account. Bimodality occurring on higher frequency than peak frequency is too rare to affect our whole resalts. Surprisingly, a much broader directional spreading than that of the field, which is interpreted by the strongly nonlinear energy transfer because of the very young waves in laboratory, is found. The parameter s depends on frequency in the same way as observed by Mitsuyasu et al.(1975, Journal of Physical Oceanography, 5, 750-760) and Hasselmann et al.(1980, Journal of Physical Oceanography, 10, 1264-1280) in the field, and the relationship between the four nondimensional parameters sm, fo, b1 and b2, determining the directional width, and ū10 (corresponding to the inverse of wave age) are given respectively. The observed distributions are found to agree well with the suggestion of Donelan et al.(1985, Philosophical Transaction of Royal Society of London, A315, 509-562) when applied to field waves.
A laboratory study of directional spectra with maximum likelihood mehod-Ⅱ Decaying swell
Zhao Dongliang, Masuda Akira, Wen Shengchang, Guan Changlong
1999, (1): 75-85.
Abstract:
From measurements by a circular array consisting of 18 wave gauges in a large wave tank, directional spectra of swell in deep water are systematically investigated with maximum likelihood method. It is shown that the disectional spreading of swell, qualitatively similar to that of developing wind wave which is narrowest in the region of peak frequency and broadens with increasing or decreasing frequency, can be effectively described by cos2s(θ/2) introduced by Longuet-Higgins et al.(1963, Ocean Wave Spectra.111-136).It is intriguing that bimodal distribution found in our experiments appears at the forward face instead of the rear face of a Ireyuency vpectrum in the cases of nonlinearity being very weak. Parameterized by nonlinearity, formulations which can be applied to swell as well as wind wave are proposed. It is concluded that nonlinear interaction plays a central role in controlling the development of directional angular spreading even for the swell.
Remote sensing composite information's trend surface analysis of Nansha Islands coral islets and reefs'top
Liu Baoyin, Wang Yanfeng
1999, (1): 87-96.
Abstract:
Based on the remote,ensing information feature of Nansha coral inlet, and reef, that controlled by the Nansha Islands local area's geological structure and growth law, by means of mathematical model and PC, the Nansha Islands coral islets and reefs' top geological data' spatial distribution and local change trend are simulated by using the trend surface system on the remote sensing composite information, and an scientific interpretation and local comparison of Nansha coral islands and islets' spatial distribution feature are made.
Adhesion of foulings on surface energy of silicone rubber coatings
Tian Jun, Xue Qunji
1999, (1): 97-102.
Abstract:
All antifouling paints in use today are effective because toxic ingredients based on heavy metals are included in their formulation, the environmental effects of organotins in seawater have been a topic of much interest and concern in recent years. This study has found that the material of rich silicone rubber on mating surface based on the low dispetsive component of surface energy makes barnacle settling on them unable to attach petntanently and is removed by moving water. The material permits only small amounts of fouling to attach, such as algae, Ciona intestinalis, because the high polar interaction of coating surface may absorb water to form water film in sea, and cause very low adhesion of the fouling species.
Analysis of grey model between seawater environmental essential factors and phytoplankon dynamics in the Dapeng Bay, the South China Sea
Huang Weijian, Qi Yuzao, Han Boping, Chen Shurong
1999, (1): 103-108.
Abstract:
The relation between the dynamics of phytoplankton and essential environmental factors of seawater has been studied. According to the comparison between environmental factors of seawater, and on the basis of mathematical space theory and the four principles of normalization, even symmetry, globality and proximity, smoothing discrete function, the grey derivative and the grey differential equation have been defined, the grey models and relation to the factors (the seawater physical and chemical factors) were estimated. The calculation results indicate that zooplankton. Mn, Fe and dissolved oxygen are the most important factors.
In situ enzyme immunoassays with tissue smears to study horizontal transmission of BMNV in penaeid shrimp and in beach animals
Song Siyang, Luo Wenxin, Chen Jin'an, Shen Mingshan, Su Wenjin
1999, (1): 109-116.
Abstract:
An enzyme immunoassay technique is developed for detecting the baculoviral midgut gland necrosis virus (BMNV) in penaeid shrimp and beach animals. An antiserum was obtained from rabbits immunized with a BMNV purified from Penaeus japnnicus.γ-globulin was isolated and labelled with horseradish peroxidase (HRP).This reagent was used to detect the virus in penaeid shrimp experimentally infected with the BMNV preparalion, in cultured penaeid shrimp and in several beach animals. The technique is specific, simple and sensitive and can be developed into a practical method for the detection of penaeid shrimp viruses. Among 128 tissue samples from 11 beach animals, 77 samples gave positive reactions with the enzyme-labelled immunoglobulin against BMNV from P. japonicas. These animals could possibly constitute a horizontal transmission pathway for cultured penaeid shrimp vcruses.
Study on the feeding habit and trophic level of main economic invertebrates in the Huanghai Sea
Cheng Jisheng, Zhu Jinsheng, Jiang Weimin
1999, (1): 117-126.
Abstract:
The stomach contents of 14 main invertebrates in the Huanghai Sea are analyzed. The results indicate that:(1) the examined predator species were all omnivore with wide food range, showing no obvious selection for spacific food items, (2) on the basis of their ecological habitat, the predators could be classified into 5 different types, i. e.,benthoelagic and planktopelagic animals, nektopelagic and planktopelagic animals, benthopelagic animals, nektopelagic and benthopelagic animals, and nektopelagic animals and (3) the trophic level of the 11 predator species, including Crangon affinis, Palaemon gravieri, Penaeus orientalis, Trachypenaeus curvirostris, Metapenaeopsis dalei, Portunus trituberculatus, Charybdis bimaculata, Oratosquilla oratorio, Sepia andreana, Loligo beka and L.japonica ranged from 2.30 to 2.72, belonging to low carnivore (trophic level:2.0-2.8), whereas that of the other 3 predator species, including Sepia esculenta, Sepiella maindroni and Todarodes pacificus were in the range of 2.86-2.97, belonging to mid-carnivore (trophic level:2.9-3.4).
Geochemistry of some major chemical composition in marine sediments of the Haitan Island
Yang Huihui, Chen Lan
1999, (1): 127-135.
Abstract:
Laws of Chl. a maximum distribution and variation in the northern East China Sea
Lu Saiying
1999, (1): 137-146.
Abstract: