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1.
The ratio of dissolved cadmium (Cd) to phosphate (PO4) in the subtropical coastal area of Ishigaki Island, Okinawa, Japan, was investigated. Twenty vertical seawater samplings
were carried out once a month from May 2008 to January 2010. In order to examine how the Cd/PO4 ratio in seawater varies with the oceanographic conditions (i.e., the water temperature–salinity characteristics), the water
masses at the study sites were classified into two types: group 1 with a water temperature of >25°C and a salinity range of
34.0–34.4, and group 2 with a water temperature of <25°C and a salinity of >34.4. A different phytoplankton assemblage was
observed in each water mass defined. Different Cd/PO4 ratios were obtained for the two water mass types, due to the differences between the types in terms of the environmental
conditions such as the water temperature–salinity (T–S) characteristics and phytoplankton assemblages, as well as possible variations in the concentrations of dissolved iron, zinc,
manganese, and CO2 in seawater in each water mass. 相似文献
2.
The effective density and the strength of flocs formed in the laboratory from mud from the Tamar Estuary reached a maximum
value at a salinity of 10–15‰ within the concentration range studied (0.1–1.0 g liter−1). For a constant salinity and concentration, the density decreases with increasing floc size. The strength of the flocs increases
with the floc diameter. However, the strength of the individual particle bonds within the floc decreases with size. Large
flocs were relatively more brittle than smaller ones. The results suggest that larger flocs may be disrupted by the formation
of unequal fragments. 相似文献
3.
Global surface layer salinity change detected by Argo and its implication for hydrological cycle intensification 总被引:1,自引:0,他引:1
Shigeki Hosoda Toshio Suga Nobuyuki Shikama Keisuke Mizuno 《Journal of Oceanography》2009,65(4):579-586
We investigated changes in the global distribution of surface-layer salinity by comparing 2003–2007 Argo-float data with annual
mean climatological surface-layer salinity data for 1960–1989 from the World Ocean Database 2005. The two datasets showed
similar patterns, with low values in subpolar and tropical regions and higher values in the subtropics. The recent Argo data
indicate that the contrast between low and high salinity has intensified in all areas except the subpolar North Atlantic.
The intensified contrast of the surface layer salinity was maintaining for 2003–2007. Using a simple method, we attempted
to estimate evaporation and precipitation changes on the basis of surface-layer salinity changes. The results show a high
probability that the global hydrological cycle has increased in the past 30 years. 相似文献
4.
Tomoharu Senjyu Noriko Asano Masaji Matsuyama Takashi Ishimaru 《Journal of Oceanography》1998,54(1):29-44
Intermediate intrusion of low salinity water (LSW) into Sagami Bay was investigated on the basis of CTD data taken in Sagami
Bay and off the Boso Peninsula in 1993–1994. In October 1993, water of low temperature (<7.0°C), low salinity (<34.20 psu)
and high dissolved oxygen concentration (>3.5 ml I−1) intruded along the isopycnal surface of {ie29-1} at depths of 320–500 m from the Oshima East Channel to the center of the
bay. On the other hand, the LSW was absent in Sagami Bay in the period of September–November 1994, though it was always found
to the south off the Boso Peninsula. Salinity and dissolved oxygen distributions on relevant isopycnal surfaces and water
characteristics of LSW cores revealed that the LSW intruded from the south off the Boso Peninsula to Sagami Bay through the
Oshima East Channel. The LSW cores were distributed on the continental slope along 500–1000 m isobaths and its onshore-offshore
scales were two to three times the internal deformation radius. Initial phosphate concentrations in the LSW revealed its origin
in the northern seas. These facts suggest that the observed LSW is the submerged Oyashio Water and it flows southwestward
along the continental slope as a density current in the rotating fluid. The variation of the LSW near the center of Sagami
Bay is closely related to the Kuroshio flow path. The duration of LSW in Sagami Bay is 0.5 to 1.5 months. 相似文献
5.
Changyou Wang Xiulin Wang Bodong Wang Chuansong Zhang Xiaoyong Shi Chenjian Zhu 《Oceanology》2009,49(1):64-72
Dissolved concentrations of Cu, Pb, Zn, and Cd were measured in the Changjiang estuary and its adjacent waters. The results
indicate that the ranges of dissolved heavy metals in the studied waters are as follows: Cu = 1.0−6.9 μg/L, Pb = 0.10−0.39
μg/L, Zn = 3.2−9.1 μg/L, and Cd = 0.011−0.049 μg/L. The behavior of the dissolved Cu was essentially conservative, but a high
scatter was observed for the high salinity samples, and it is the same with Zn and Pb. The overall concentrations of dissolved
Cd increase with the salinity. There were no differences between the surface, middle, and bottom layer for Cu, Pb, Zn, and
Cd. Seasonal changes of their averages were not obvious on the whole. River discharges, sedimentary dynamics, and biological
processes might determine the profiles of heavy metals.
The text was submitted by the authors in English. 相似文献
6.
The concentrations of Cu, Ni and Cd were determined in Funka Bay during a spring phytoplankton bloom, consisting of diatoms.
Just after the bloom, both dissolved Cd and nutrients were removed in the euphotic zone. However, the removal ratio of Cd
to phosphate was very different from that in seawater. The removal of Cd took place at a Cd/phosphate ratio of 0.07×10−3, which was lower than in seawater before the bloom (0.25×10−3), leading to an increase in this ratio in seawater exceeding 0.7×10−3 at the end of the bloom. Elevated concentrations of Cd and phosphate were observed in the deeper layer after the bloom due
to the decomposition of detrital materials produced in the bloom. The ratio of Cd/phosphate in the regeneration step was 0.24×10−3 which was different from the removal ratio of 0.07×10−3. These observations suggest that the high Cd/phosphate ratio in the regeneration would reflect a relatively high regeneration
rate of Cd than that of phosphate. No significant decrease in Cu and Ni concentrations was observed during the development
of the bloom, suggesting that biological removal of these metals was not so significant during the spring bloom. The concentrations
of Cd, Cu and silicate in surface waters increased after the bloom with decreasing salinity due to the influence of a spring
thaw. 相似文献
7.
By using the archival hydrological data for 1955–1998, we analyze the trends of deep-water thermohaline characteristics of
the Black Sea and their interannual and decadal variability. It was discovered that the level of salinity increased at depths
greater than 1000 m in the west part of the sea from the mid-1950-s till the early 1980s and the opposite trend was observed
for the next 15–20 yr. The average rate of increase in the deep-water salinity between 1960 and 1980 and its decrease after
1980 was equal to 0.05‰ per 20 yr. These facts demonstrate that the water exchange through Bosporus was intensified for the
first 25 yr of the analyzed period and weakened for the next 20 yr. The interannual variability with a typical period of 6.5
yr and a quasi-20-yr periodicity are detected against the background of the parabolic trend.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 18–30, July–August, 2006. 相似文献
8.
O. R. Andrianova 《Physical Oceanography》1997,8(2):117-122
The paper considers the correlation between the variability of river discharges in the northwestern Black Sea and water salinity
(from 1962 to 1994). As the most complete series, we have chosen salinity data collected at the port of Odessa. The dominant
oscillations in the intra-annual variability of river discharges (Danube, Dniester, Dnieper, Yuzhny Bug) and salinity attain
about 2–3 months and one year, respectively. In the inter-annual variability of river discharges and water salinity, cyclicities
equal to about 4–6 months and 9–12 years, respectively, have been identified. Through analysing the inter-annual variations,
an inversely proportional dependence has been found between the overall river discharges and salinity (between discharges
in April and salinities in May, the correlation coefficient has amounted to −0.61). For each river, we have obtained the following
dependences: for Odessa-Dniester, −0.72; and for Odessa-Danube, −0.65.
Translated by Vladimir A. Puchkin. 相似文献
9.
A new type of pycnostad has been identified in the western subtropical-subarctic transition region of the North Pacific, based
on the intensive hydrographic survey carried out in July, 2002. The potential density, temperature and salinity of the pycnostad
were found to be 26.5–26.7 σ
θ
, 5°–7°C and 33.5–33.9 psu respectively. The pycnostad is denser, colder and fresher than those of the North Pacific Central
Mode Water and different from those of other known mode waters in the North Pacific. The thickness of the pycnostad is comparable
to that of other mode waters, spreading over an area of at least 650 × 500 km around 43°N and 160°E in the western transition
region. Hence, we refer to the pycnostad as Transition Region Mode Water (TRMW). Oxygen data, geostrophic current speed and
climatology of mixed layer depth in the winter suggest that the TRMW is formed regularly in the deep winter mixed layer near
the region where it was observed. Analysis of surface heat flux also supports the idea and suggests that there is significant
interannual variability in the property of the TRMW. The TRMW is consistently distributed between the Subarctic Boundary and
the Subarctic Front. It is also characterized by a wide T-S range with similar density, which is the characteristic of such
a transition region between subtropical and subarctic water masses, which forms a density-compensating temperature and salinity
front. The frontal nature also tends to cause isopycnal intrusions within the pycnostad of the TRMW. 相似文献
10.
On the basis of processing of the oceanographic data accumulated for the water area of the North Atlantic in 1950–1999 (∼500,000
stations), we study seasonal and interannual variations of the principal characteristics of pycnocline within the range of
σt = 25.5–27.5 conventional density units. It is shown that the interannual oscillations of these characteristics in the entire
analyzed layer can be regarded as a superposition of fluctuations with periods from 2–3 to 10–12 yr. The typical ranges of
these fluctuations for the depths of occurrence of isopycnic surfaces and the corresponding temperature and salinity are equal
to 20–25 m, 1–1.5°C, and 0.25‰, respectively. The intensification of atmospheric circulation at middle latitudes is accompanied
by the simultaneous deepening of the pycnocline and its heating in the central part of the North Subtropical Anticyclonic
Gyre. At the same time, the process of weakening of the atmospheric circulation leads to the rise of the pycnocline and its
cooling. The complete cycle of interaction of the North-Atlantic Oscillation with the anomalies of isopycnic characteristics
(with regard for the period of their advection) is equal to ∼6–8 yr.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 29–48, March–April, 2007. 相似文献
11.
Habitat suitability index of Chub mackerel (<Emphasis Type="Italic">Scomber japonicus</Emphasis>) from July to September in the East China Sea 总被引:1,自引:0,他引:1
The habitat quality of Chub mackerel (Scomber japonicus) in the East China Sea has been a subject of concern in the last 10 years due to large fluctuations in annual catches of
this stock. For example, the Chinese light-purse seine fishery recorded 84000 tons in 1999 compared to 17000 tons in 2006.
The fluctuations have been attributed to variability in habitat quality. The habitat suitability Index (HSI) has been widely
used to describe fish habitat quality and in fishing ground forecasting. In this paper we use catch data and satellite derived
environmental variables to determine habitat suitability indices for Chub mackerel during July to September in the East China
Sea. More than 90% of the total catch was found to come from the areas with sea surface temperature of 28.0°–29.4°C, sea surface
salinity of 33.6–34.2 psu, chlorophyll-a concentration of 0.15–0.50 mg/m3 and sea surface height anomaly of −0.1–1.1 m. Of the four conventional models of HSI, the Arithmetic Mean Model (AMM) was
found to be most suitable according to Akaike Information Criterion analysis. Based on the estimation of AMM in 2004, the
monthly HSIs in the waters of 123°–125°E and 27°30′–28°00′ N were more than 0.6 during July to September, which coincides
with the catch distribution in the same time period. This implies that AMM can yield a reliable prediction of the Chub mackerel’s
habitat in the East China Sea. 相似文献
12.
V. V. Knysh G. K. Korotaev S. G. Demyshev V. N. Belokopytov 《Physical Oceanography》2005,15(3):142-160
We compare the thermohaline and dynamic characteristics of the Black Sea reconstructed by using two versions of climatic temperature
and salinity fields:old (1903–1982)and new (1903–2003). The fields are reconstructed with the help of continuous assimilation
of the climatic temperature and salinity in the model. It is shown that the climatic thermohaline fields constructed with
regard for the data of observations for the last 20 yr are characterized by an insignificant elevation of the halocline (pycnocline)in
the winter-spring period and the elevation of the upper boundary of the cold intermediate layer in the spring-summer period.
The intensity of surface geostrophic currents is greater than the same quantity computed on the basis of the old climatic
data for the whole year. The horizontal currents in the sea computed according to the new climatic data are more intense.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 11–30, May–June, 2005. 相似文献
13.
The mechanism by which nutrient is supplied to a warm-core ring (WCR) was investigated in order to understand the greater
productivity of WCR than that of the Kuroshio, where the WCR originattes. A single WCR was observed in January and May, 1997.
The thermostad (a layer of isothermal and isohaline water) of the WCR had different properties from January to May, the differences:
Δwater temperature: −0.698°C, Δsalinity: −0.048, Δsigma θ: +0.072, Δnitrite+nitrate-N: +1.83 μM, Δphosphate: +0.011 μM and
Δsilicate: +3.2 μM. We examined three possible mechanisms for nutrient supply to WCR in winter, namely: 1) inflow of the Oyashio
surface water into WCR; 2) isopycnal mixing with Oyashio water; 3) entrainment of the water below the WCR into the WCR. The
results were as follows: 1) When the decrease of salinity was due to the inflow of the Oyashio surface water, the increase
of nutrients (nitrite+nitrate-N, phosphate-P and silicate-Si) was estimated to be only 17–27% of the observed increase. 2)
When the decrease of salinity was due to isopycnal mixing, the increase of nutrients was estimated to be 30–42% of the observed
increase. 3) When the decrease of salinity in the WCR in May was due to entrainment of the water below the WCR in winter by
convection, the mixing depth was calculated be 620 m according to the salt budget. The increase of nutrients in this case
was calculated to be 82–95% of the observed increase. The main mechanism of nutrient supply to WCR was concluded to be due
to the entrainment of the water below the WCR by winter mixing.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
Chiho Sukigara Toshio Suga Toshiro Saino Katsuya Toyama Daigo Yanagimoto Kimio Hanawa Nobuyuki Shikama 《Journal of Oceanography》2011,67(1):77-85
A profiling float equipped with a fluorimeter, a dissolved oxygen (DO) sensor, and temperature and salinity sensors was deployed
in the subtropical mode water (STMW) formation region of the North Pacific. It acquired quasi-Lagrangian, 5-day-interval time-series
records from March to July 2006. The time-series distribution of chlorophyll showed a sustained and sizable subsurface maximum
at 50–100 m, just above the upper boundary of the STMW, throughout early summer (May–July). The DO concentration in this lower
euphotic zone (50–100 m) was almost constant and supersaturated in the same period, becoming more supersaturated with time.
On the other hand, the DO concentration at 100–150 m near the upper boundary of the STMW decreased much more slowly compared
with the main layer of STMW below 150 m, even though oxygen consumption by organisms was expected to be larger in the former
depth range. The small temporal variations of DO in the lower euphotic zone and near the upper boundary of the STMW were reasonably
explained by downward oxygen transport because of large diapycnal diffusion near the top of the STMW. Assuming that the oxygen
consumption rate at 100–150 m was the same as that in the main layer of STMW and compensated by the downward oxygen flux,
the diapycnal diffusivity was estimated to be 1.7 × 10−4 m2 s−1. Nitrate transport into the euphotic zone by the same large diffusion was estimated to be 0.8 mmol N m−2 day−1. All of the transported nitrate could have been used for photosynthesis by the phytoplankton; net community production was
estimated to be 5.3 mmol C m−2 day−1. 相似文献
15.
The data of meteorological and oceanographic observations on the northwest shelf of the Black Sea for 1973–2000 are used to
compute the characteristics of the entire area in the presence of hypoxia of waters under the pycnocline in the summer–autumn
period and the area of surface waters with a level of salinity lower than 17.5‰ in May. The time of onset of the spring warming
of air (stable transition through a temperature of 5°) is determined. A statistically significant positive trend of the air
temperature (0.8° per 100 yr) is revealed in Odessa. The process of warming was observed mainly for the winter (1.5° per 100
yr) and spring (0.8° per 100 yr) periods and became especially intense since the beginning of the 1990s. On the basis of the
data of correlation analyses, we establish a statistically significant relationship between the large-scale atmospheric processes
[the index of North Atlantic Oscillation (NAO) and the wind conditions], the area of surface waters whose salinity is lower
than 17.5‰, and the total area with hypoxia in the summer–autumn periods. For positive mean values of the NAO index (in January–March),
we most often observe early spring with elevated repetition of the south and west winds with subsequent development of hypoxia
in large areas of the northwest shelf. We propose an empirical regression model for the prediction of the total area of summer–autumn
hypoxia of waters with predictors: the onset of the spring warming of air and the area of propagation of waters whose salinity
is lower than 17.5‰ in May. The maximum error of prediction of the area with hypoxia does not exceed 5.5 ⋅ 103 km2, i.e., less than 2% of the total area of the northwest shelf in the Black Sea (to the north of 45°N). 相似文献
16.
S. I. Prokopiev T. E. Ovchinnikova O. F. Vasiliev 《Izvestiya Atmospheric and Oceanic Physics》2010,46(2):256-260
To adequately describe the hydrophysical processes in water bodies with a high mineralization, it is necessary to take into
account the dependence that the thermodynamic characteristics of water have on the amount of salts contained in it. This work
investigates some widely known formulas for calculating a number of thermodynamic parameters of mineralized water. The density,
freezing temperature, specific heat of evaporation, and relative pressure of saturated vapor over the surface are considered.
The possibilities of using these formulas when modeling hydrophysical processes in water bodies with salinity in the range
of 0–250 pro mille are analyzed. It is shown that the formulas under consideration should be used when the salinity does not
exceed 100 pro mille. If the mineralization is higher, it is necessary to elaborate more suitable formulas on the basis of
an approximation of in situ data or data from handbooks. 相似文献
17.
Preliminary results of in-situ XCTD/CTD comparison test 总被引:4,自引:0,他引:4
The current status of XCTD manufactured by the Tsurumi Seiki Co. is described based on XCTD/CTD comparison tests conducted
in the Pacific and Indian Ocean in November 1996 and January 1997 respectively. The falling rates of used probes are generally
consistent and differences between individual probes stay within a small range of +/−5 m through the full depth range (0–1000
m), although the rate is slightly different from the depth-time equation provided by the manufacturer. Temperature and salinity
accuracy is estimated to be better than 0.05°C and 0.05 psu respectively. Comparison of vertical temperature/salinity sections
of XCTD/CTD constructed separately along a line on which XCTD stations locate midway of CTD stations. The hydrographic structures
obtained are generally consistent, and the difference of surface dynamic height (referred to 1000 db) is 0.03 dyn m in RMS. 相似文献
18.
In this study we test Talley's hypothesis that Oyashio winter mixed-layer water (26.5–26.6σ θ) increases its density to produce the North Pacific Intermediate Water (NPIW) salinity minimum (26.7– 26.8σθ) in the Mixed Water Region, assuming a combination of cabbeling and double diffusion. The possible density change of Oyashio
winter mixed-layer water is discussed using an instantaneous ratio of the change of temperature and salinity along any particular
intrusion (R
l
). We estimate the range of R
l
DD
required to convert Oyashio winter mixed-layer water to the NPIW salinity minimum due to double diffusion, and then assume
double-diffusive intrusions as this conversion mechanism. A double-diffusive intrusion model is used to estimate R
l
DD
in a situation where salt fingering dominates vertical mixing, as well as to determine whether Oyashio winter mixed-layer
water can become the NPIW salinity minimum. Possible density changes are estimated from the model R
l
DD
by assuming the amount of density change due to cabbeling. From these results, we conclude that Oyashio winter mixed-layer
water contributes to a freshening of the lighter layer of the NPIW salinity minimum (around 26.70σθ) in the MWR. 相似文献
19.
The seasonal abundance of the dominant dinoflagellate, Ceratium fusus, was investigated from January 2000 to December 2003 in a coastal region of Sagami Bay, Japan. The growth of this species
was also examined under laboratory conditions. In Sagami Bay, C. fusus increased significantly from April to September, and decreased from November to February, though it was found at all times
through out the observation period. C. fusus increased markedly in September 2001 and August 2003 after heavy rainfalls that produced pycnoclines. Rapid growth was observed
over a salinity range of 24 to 30, with the highest specific rate of 0.59 d−1 measured under the following conditions: salinity 27, temperature 24°C, photon irradiance 600 μmol m−2s−1. The growth rate of C. fusus increased with increasing irradiance from 58 to 216 μmol m−2s−1, plateauing between 216 and 796 μmol m−2s−1 under all temperature and salinity treatments (except at a temperature of 12°C). Both field and laboratory experiments indicated
that C. fusus has the ability to grow under wide ranges of water temperatures (14–28°C), salinities (20–34), and photon irradiance (50–800
μmol m−2s−1); it is also able to grow at low nutrient concentrations. This physiological flexibility ensures that populations persist
when bloom conditions come to an end. 相似文献
20.
To study the long-term variability of the thermohaline and dynamic characteristics of the Black Sea, we use three versions
of climatic fields, namely, the fields reconstructed in the model according to the old (1903–1982) and new (1903–2003) hydrological
climatic data arrays of temperature and salinity and according to the data of satellite altimetry. The analysis of the altimetry-based
climatic fields confirms the distinctions (established earlier according to the old and new data arrays) in the seasonal variability
of the integral characteristics of temperature and salinity and in the structures of hydrophysical fields in the sea. It is
shown that, in the winter-spring season, the thermohaline fields reconstructed according to the new and altimetry data arrays
are characterized by a small elevation of the halocline (pycnocline) and the upper boundary of the cold intermediate layer.
In all seasons, the altimetry-based surface geostrophic currents contain numerous mesoscale eddies with different signs of
rotation. Moreover, in all seasons, the Rim Current reconstructed according to the altimetry data is characterized by a narrower
jet almost along the entire its length. This jet is especially intense near the coasts of West Anatolia.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 3–17, July–August, 2006. 相似文献