1999 Vol. 18, No. 2

Display Method:
Sensitivity study of coastal plumes
Wang Jia, Mo Ruxi, Gao Zhenhui, Yin Zhongbin, Chen Mingjian
1999, (2): 147-166.
A three-dimensional numerical model of the coastal plume in an ideal basin for the western Gulf of Maine of USA, based on the observations, was configured to examine the dynamical properties under the spring riverine, tidal, and wind forcing.The purpose of this paper is to reveal possible effects of different factors on the coastal plume.The control run with a sloping bottom mimicking the western Gulf of Maine reproduced a southward advection speed of 14 km/d, rnnsistent with the observed speed of 13.3 km/d.The plume evolutions due to the two typical wind forcing, upwelling favourable (wind from north) and downwelling favourable (wind from south), were simulated to explain the observations during the spring of 1993.A systematic sensitivity study was also conducted on the following themes:model parameters, dynamic processes, and topography effect.
Diurnal SST warming in the Bay of Biscay: satellite measurements and model prediction
Huang Weigen, I. S. Robinson, N. C. Wells
1999, (2): 167-176.
NOAA AVHRR data from the Bay of Biscay between 1988 and 1990 have been examined in order to extract information on the fluctuations of sea surface temperature (SST) at the diurnal time scale.The temporal and spatial distributions of diurnal warming in the area are obtained.The diurnal warming occurs during the summer months.Large diurnal warming in excess of 1℃ is found within 100 km along the west coast of France and within 30 km along the north coast of Spain.In the central Bay of Biscay the diurnal warming is typically about 0.5℃.The diurnal warming up to 6℃ is observed occasionally in the coastal areas where the wind speed is very low.
A one-dimensional oceanic mixed-layer model has been used to simulate the diurnal warming.The results demon-strate that the diurnal warming increases with the decrease of the wind speed and the increase of the net heat flux.The comparison shows that the model results are in good agreement with the satellite measurements.
Analysis of sea surface height variabilities in the Kuroshio Current region by using Geosat altimeter data
Pan Jiayi, Yuan Yeli, Zheng Quan'an
1999, (2): 177-189.
The Geosat altimeter ERM T2-GDRs data were used to analyze sea surface height (SSH) variabilities in the Northwest Pacific region of 10°-45°N, 120°-160°E covering all the Kuroshio Current.After processing the Geoset GDRs data, the 50 gridded SSH anomaly fields were acquired.The comparison between the SSH anomalies and tidal gauge sea levels showed that the altimeter data accorded with the tidal gauge data especially in the low frequency scale and in open sea.The mesoscale variability energy distribution obtained from the SSH anomalies was controlled by the position of the Kuroshio, bottom topography and the stationary meander of the Kuroshio.The relative transports of the Kutoshio Extension and the Kuroshio south of Japan, represented by the difference between the SSH anomalies on two sides of the current, had strong interennual and seasonal cycles, which was related to the Kuroshio large meander.When the Kuroshio meander occurred, the transport of the Kuroshio east of the Tokara Strait decreased, but that northeast of Taiwan Island increased.The variability of the transport east of the Philippines reflected the effects of the ENSO.The EOF analysis of the SSH anomaly fields showed that the first three EOFs accounted for 25.3%,17.1% and 13.7% of the total variance, and represented the meander mode, the ENSO mode and season mode respectively.
A baroclinic typhoon model with a moving multi-nested grid and variational adjustment initialisation Ⅰ. Numerical method
Wu Huiding, Yang Xuelian, Bai Shan, Li Guoqing
1999, (2): 191-201.
A baroclinic typhoon model with a moving multi-nested grid is applied in marine environmental forecasts.This paper describes the numerical methods of the model including governing equations, finite differencing, split scheme and time integration.
Response of global subtropical highs to the equatorial eastern Pacific SST anomaly
Gong Daoyi, Wang Shaowu
1999, (2): 203-214.
Based on the reanalysis data of global SOOhPa gcopotential height (NCEP NCAR CDAS-1) and tropical Pacific SSTs, the characteristics of global subtropical highs and their response to tropical eastern Pacific SST are investigated.Results show that global subtropical highs respond to SST consistently.Subtropical high intensity correlates to the 3 months leading SST maximally.The relationship between SST and SOOhPa height stands out in low latitudes.The time for 500hPa height reaching maximum correlation to SST is 2 months later in latitude of 10 degree and 9 months in latitude of 30 degree than equatorial wne.And the response of atmospheric circulation over extratropic performs as wave train, and the response is more significant in the condition of warmer SST.Persistence of SSTs and subtropica highs changes obviously from season to season.Minimum persistence of subtropical highs in September and October may relate to the low persistence of SSTs in August and September.
Satellite SAR observation of shallow bottom topography of the east Australia Sea
Zhou Changbao, G. Cresswell, P. Tildesley, C. S. Nilsson
1999, (2): 215-223.
A preliminary account of synthetic aperture radar (SAR) imaging mechanisms of oceanic bottom topographic features and a description of the principles of the information extracted from SAR images and the processing and the analysis technology of SAR images are made.Some results were obtained from researching shallow topography and its bathymetric features of the regions of offshore in the east Australia Sea by ERS-1 SAR images.The preliminary research indicates that these features covered with SAR have never been reported before and some results of them are yielded for the first time in Australia.This information is very valuable in a great number of applications to oceanic engineering, shipping navigation, marine fishery and environment, as well as oceanographic research and development.The paper comes to the conclusion that SAR remote sensing of oceanography and its applications are of great potential.
Sectional distribution of salinity and its indication of Kuroshio's intrusion in the southern Taiwan Strait and northeastern South China Sea late summer, 1994
Hu Jianyu, Liang Hongxing, Zhang Xuebin
1999, (2): 225-236.
Using the CTD data investigated at about 330 stations in the southern Taiwan Strait, the northeastern South China Sea and their adjacent seas in August and September of 1994, this paper anayses the sectional distributions of salinity in 10 selected sections end discusses the possibility of the Kuroshio's intrusion into the northeastern South China Sea and the southern Taiwan Strait.The results show that:as the main stream of Kuroshio passes by the northern Luzon Strait during the survey period, the "Kuroshio-influenced water" with some hydrological features of the Kuroshio may extend through the Luzon Strait to the sea areas near both the Dongsha Islands and the Taiwan Shoel of the southern Taiwan Strait.
Distributional features of temperature and salinity in the southern Taiwan Strait and its adjacent sea areas in late summer, 1994
Hu Jianyu, Liang Hongxing, Zhang Xuebin
1999, (2): 237-246.
Based on the CTD data obtained in the southern Taiwan Strait and its adjacent areas in August and September of 1994, the distributional features of the temperature and salinity in the studied area have been analyzed in detail.The results are as follows:(1) There are two low temperature and high salinity regions in the nearshore area between Dongshan and Shantou and in the southeastern Taiwan respectively, which may be caused by upwellings.(2) There exists a cold eddy in the northwestern sea area and a warm eddy with two high temperature cores in the eastern sea area of the Islands, which are related to the anti-cyclonic turning of the seawater near the Dongsha Islands.(3) A westward high temperature and high salinity water tongue extends through the northern Luzon Strait and reaches the sea areas near the Dongsha Islands and southern Taiwan Strait.
Behavior features of heavy metals in the Haikou Bay waters
Chen Chunhua, Wang Zhengfang, Lü Haiyan
1999, (2): 247-255.
Dissolved Cu, Pb, Zn and Cd in the I-Iaikou Bay waters were measured to be respectively in the range concentrations of 0.47-1.16μg/dm3, 0.94-2.36 μg/dm3, 1.28-4.83 μg/dm3 and 0.005-0.072 μg/dm3; with respectively average values of 0.78 μg/dm3, 1.36 μg/dm3, 3.14 g/dm3 and 0.03 μg/dm3.Dissolved Cu and Zn concentrations are relatively high at the stations near the Longkun Road Outfall for domestic sewage, the Xiuying Out-fall for industry waste water and the Haidian Island Estuary, but dissolved Pb and Cd concentrations are low in these stations.The values in other stations are comparatively homogenous.Vertical dissolved Cu, Pb and Zn concentrations at the bottom layer are higher than at the surface layer, but dissolved Cd concentration appears to be on the opposite.The measurement results of Cu, Pb, Zn and Cd in suspended particle show that particulate matters in the Haikou Bay seeweter play a role in purifying heavy metals.The study on strong complexed form and non-liable form of dissolved copper show that the ratio of strong complexed form and dissolved form is about 85%,and non-liable form is very low with a value lower than 5 nmol/dm3.Therefore, nipper in the I-Iaikou Bay seawater cannot cause influence on marine organisms.
Study on mineral structural stability of marine 1nm manganate
Qian Jiangchu
1999, (2): 257-266.
In order to study the phase transformation between 1nm manganate and 0.7nm mangenate, a series of Slnm Me2+ tnanganates were made after the synthetic lnm Na+ manganate substituted with different kinds of divalent rations.The X-ray diffraction analysis of wet Slnm Me2+ manganates after 24 h room temperature dry showed that their basal d-spacing had been changed, indicating that there was phase transformation between lnm and 0.7nm manganates.Those 1nm tnanganates with unstable structure rnllapsed into 0.7nm manganate by losing one interlayer OH-H2O, while those with stable structure still retained the 1nm d-spacing.This factor reminds us that the manganese nodule samples must be kept in wet condition to avoid the misleading results.The structural stability of lnm manganate is mainly controlled by the interlayer divalent rations.There is a possitive correlation between the amount of rations in the interlayer and the structural stability, while the capacity of different rations in stabilizing the structure of 1nm manganate is as follows:
Ni > Cu > Co > Zn > Ca > Mg > Na.
Study on topographic compensation model of the Okinawa Trough Ⅰ. Calculation of theoretical isostatic response function
Liu Baohua, Wu Jinlong, Xin Baisen, Peng Chao
1999, (2): 267-272.
Based on regional compensation and experimental isostasy, the calculating formula of theoretical isostatic response function is deduced when the loads on top correlate with loads from below.A variety of curves of theoretical isostatic response function were calculated with different effective elastic thickness of the plate and by using different proportions between loads on top and loads from below.And preliminary discussion is made on shapes of the curves.
Study on topographic compensation model of the Okinawa Trough Ⅱ. Geological interpretation of isostatic response function of the Okinawa Trough
Xin Baisen, Liu Baohua, Xia Zhifeng
1999, (2): 273-278.
Based on regional compensation model and experimental isostasy, the isostatic response function of the Okinawa Trough is calculated by using gravity and topographic data.The results are shown as follows:the effective elastic thickness of the plate and compensation depth in the southern Okinawa Trough is obviously greater than those in the middle Okinawa Trough.In reference with other geological and geophysical data, the differences between the two portions are explained to be caused mainly by their differences in temperature of the lithosphere and the compensation mechanism.
A two-layer simple baroclinic equation ocean model and its simulations of ocean currents in winter and summer
Yang Bo, Qian Yongfu
1999, (2): 279-291.