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1.
The qualitative and quantitative compositions of free-living marine nematodes were studied in Rifovaya Bay (Peter the Great Gulf, Sea of Japan). It was found that the density distribution of nematode populations in bottom sediments of Rifovaya Bay is nonuniform. In total, 72 nematode species were found, including Oncholaimium paraolium, Viscosia epapilosa, and Monoposthia latiannulata on all types of substrates. The dominant trophic group comprised “predators” (2B) and “scrapers” (2A). It was shown that the species composition of nematodes in Rifovaya Bay is very similar to the species composition of nematodes in the other areas of Peter the Great Gulf.  相似文献   

2.
Walleye pollock (Gadus chalcogrammus) is one of the popular fish species in Korea and known to frequently harbor anisakid nematodes. Despite many papers regarding walleye pollock having been published, there is no information on the prevalence and distribution of anisakid nematodes from walleye pollock in Korean waters. We investigated 716 walleye pollock caught from Goseong, the East Sea of the Korean Peninsula during May 2015–December 2016. In total, 1,085 nematodes were collected and subsequently identified by PCR-RFLP analysis of internal transcribed spacer region of ribosomal DNA. The prevalence and mean intensity of anisakid nematodes was 63.6% (68/107) and 4.4 larvae/fish (297/68) in samples of 2015, and 21.5% (131/609) and 6.0 larvae/fish (788/131) in samples of 2016. The most abundantly isolated anisakid nematode was Anisakis simplex (Rudolphi, 1809) (73.5%, 798/1,085), followed by Contracaecum osculatum (Rudolphi, 1802) (3.1%, 34/1,085), Hysterothylacium aduncum (Rudolphi, 1802) (2.9%, 31/1,085), Anisakis pegreffii (Campana-Rouget and Biocca, 1955) (1.4%, 15/1,085), and a hybrid genotype (0.4%, 4/ 1,085). The mitochondrial DNA cox2 gene sequences of randomly selected A. simplex showed the highest similarity (99.5%–98.8%) with those from chub mackerel (Scomber japonicus) in Japan or from chum salmon (Oncorhynchus keta) in Korea. The mtDNA cox2 gene sequences of C. osculatum showed the highest similarity (99.0%) with those from bearded seals in Japan. All of these results give us clues to the geographical distribution, migration route and prey items of walleye pollock caught off Korea. Further extensive analyses will be necessary to get more information on the biology of Korean walleye pollock.  相似文献   

3.
Macrofauna in the Clarion-Clipperton Fracture Zone remain poorly understood, due both to gross undersampling and to the fact that most species collected from the area are new to science. Evaluation of the diversity and species distribution of the benthic fauna in this area is critical to predicting and managing the impacts of manganese nodule mining. In this study, we investigated the distribution of macrofauna to understand the natural variability in the macrobenthic community and, by extension, to establish a baseline for environmental risk assessment. Samples were collected from the KR5 block of the Korea Contract Area, within the abyssal area of the Clarion-Clipperton Fracture Zone in the northeastern Pacific Ocean, by the RV Onnuri from 2012–2014. A total of 36 core samples were examined in the survey, from which we identified 183 macrobenthic species in 25 faunal groups with a mean density of 257 ind/m2. Not taking into account meio-faunal groups such as nematodes and harpacticoid copepods, the highest percentage of individuals was represented by Arthropoda. The dominant species (> 1% of total density) were the tanaids Typhlotanais sp.1, and Akanthophoreus spp. and Stenotanais sp., the isopod Macrostylis sp.1, and the polychaetes Cirratulidae spp. and Levinsenia uncinata. The abundances of the two dominant species, the tanaid Typhlotanais sp1. and isopod Macrostylis sp.1., were positively correlated with total organic carbon (TOC). There were no differences in macrofaunal density and community structure between preserved areas (PRA), the potential benthic impacted site (BIS), and other areas near the BIS. In general, higher diversity was associated with homogeneous environmental conditions, with high nodule coverage (> 50%) and TOC.  相似文献   

4.
海水石油类物质吸收系数遥感化提取算法研究   总被引：2，自引：0，他引：2  
Establishing the remote sensing algorithm of retrieving the absorption coefficient of seawater petroleum substances is an efficient way to improve the accuracy of retrieving a seawater petroleum concentration using a remote sensing technology. A remote sensing reflectance is a basic physical parameter in water color remote sensing. Apply it to directly retrieve the absorption coefficient of seawater petroleum substances is of potential advantage. The absorption coefficient of waters containing petroleum [ACWCP, a_o(λ)], consists of the absorption coefficient of pure water [ACPW, a_w(λ)], plankton [ACP, a_(ph)(λ)], colored scraps [ACCS, a_(d,g)(λ)], and petroleum substance [ACPS, a_(oil)(λ)]. Among those, ACCS consists of the absorption coefficient of nonalgal particle [ACNP, a_d(λ)] and colored dissolved organic matter [ACCDOM, a_g(λ)]. For waters containing petroleum, the retrieved ACCS using the existing method is a combination absorption coefficient of ACNP,ACCDOM and ACPA [CAC, a_(d,g,oil)(λ)]. Therefore, the principle question is how to extract ACPS from CAC.Through the analysis of the three proportion tests conducted between the year of 2013 and 2015 and the corresponding remote sensing data, an algorithm of retrieving the absorption coefficient of petroleum substances is proposed based on remote sensing reflectance. First of all, ACPS and CAC are retrieved from the reflectance using the quasi-analytical algorithm(QAA), with some parameter modified. Secondly, given the fact that the backscatter coefficient [BC, b_(bp)(555)] of total particles at 555 nm can be obtained completely from the reflectance, the relation between BC and ACNP in petroleum contaminated water can be established. As a result, ACNP can be calculated. Then, combining the remote sensing retrieving algorithm of a_g(440), the method of achieving the spectral slope of the absorption coefficient can be established, from which ACCDOM,can be calculated. Finally, ACPS can be computed as the residual. The accuracy of ACPS based on this algorithm is 86% compared with the in situ measurements.  相似文献   

5.
The species composition and seasonal dynamics of the population density and biomass of the prasinophycean algae of the genus Pyramimonas were investigated in the Russian waters of the East/Japan Sea. According to literature data and the results of our observations, eight species of the prasinophycean algae were identified, and some of them were new for the Russian waters of the East/Japan Sea as follows: P. aff. amylifera Ñonrad, P. aff. cordata McFadden, Hill et Wetherbee, and P. nansenii Braarud. An analysis of their seasonal dynamics showed that the most conspicuous winter peak of the population density of Pyramimonas species in the Amurskii Bay was clearly distinguishable in February. In winter and early spring, the prasinophycean algae made a considerable contribution of 28 to 60% into the total population density on the background of a relatively low biomass, 1.1–14.4% of the total phytoplankton biomass in the Amurskii Bay. In the Golden Horn Bay, the summer peak of the population density of Pyramimonas species was most intensive in June. In summer, during the period of mass development of the algae of the genus Pyramimonas in the Golden Horn Bay, the prasinophycean algae contributed up to 71% of the total population density and up to 84% of the total microalgal biomass. An increase was noted in the density and biomass of the Pyramimonas species in the polluted waters near the sewage water outlets in the Amurskii and Golden Horn bays.  相似文献   

6.
Mesozooplankton community structure and environmental factors were monitored monthly at a fixed station off Tongyeong, southeastern coast of Korea, from 2011 to 2014 to better understand the variability of the mesozooplankton community in relation to changes in the marine environment. Total mesozooplankton density varied from 747 to 8,945 inds. m-3 with peaks in summer. The surface water temperature (r = 0.338, p < 0.05) and chlorophyll-a (Chl-a) concentration (r = 0.505, p < 0.001) were parts of the factors that may have induced the mesozooplankton peaks in summer. Copepods accounted for 71% of total mesozooplankton. Total copepod density, particularly cyclopoid copepods, increased during the study period. Cumulative sum plots and anomalies of the cyclopoid copepod density revealed a change of the cyclopoid density from negative to positive in June 2013. A positive relationship between cyclopoid copepods and the Chl-a concentration (r = 0.327, p < 0.05) appeared to be one of the reasons for the increase in cyclopoids. Dominant mesozooplankton species such as Paracalanus parvus s.l., Oikopleura spp., Evadne tergestina, Cirripedia larvae, Corycaeus affinis, Calanus sinicus, and Oithona similis accounted for 60% of total mesozooplankton density. Based on cluster analysis of the mesozooplankton community by year, the seasonal distinction among groups was different in 2014 compared to other years. P. parvus s.l. and its copepodites contributed most in all groups in all four years. Our results suggest that the high Chl-a concentration since 2013 may have caused the changes in mesozooplankton community structure in the study area.  相似文献   

7.
The spatial distributions of δ13C, δ15N, and n-alkanes were investigated to determine the source and transportation of allochthonous organic matter from the mouth of the Seomjin River to the southern inner shelf break of Korea. Total organic carbon (%) ranged from 0.3% to 1.6% (average = 0.80%, n = 81), and the C/N ratio varied from 2.4 to 12.4 (average = 6.76, n = 81). The δ13C values ranged from ?25.86 to ?20.26‰ (average = ?21.47‰, n = 81), and δ15N values ranged from 4.37‰ to 8.57‰ (average = 6.72‰, n = 81). The contribution of the terrestrial fraction of organic matter to the total ranged from 4.4% to 97.7% (average = 24.4%, n = 81), suggesting higher amounts around the catchment area and lower amounts in the offshore area. The concentration of total n-alkanes (nC25 ? nC35) was higher at the boundary between the outer bay and inner shelf break (BOBIS). Average chain length and the carbon preference index both indicated that major leaf wax n-alkanes accounted for the observed distribution of terrestrial organic matter, and were dominant in the inner shelf break (around BOBIS) and outer shelf break. Based on the spatial distribution of the total n-alkanes and the sum of nC27, nC29, and nC31, the terrestrial organic matter distribution was considered to be controlled by local oceanographic conditions, especially at the center of the BOBIS. In addition to enabling the distribution and source of terrestrial organic matter to be identified, the n-alkanes indicated that minor anthropogenic allochthonous organic materials were superimposed on the total organic materials in the central part of Yeosu Bay and the catchment area. The n-alkane indices revealed weathered petroleum contamination, with contamination levels being relatively low at the present time.  相似文献   

8.
Phytoplankton and bacteria diversity were studied before, during and after red tide phenomena during spring season 2015 in the Eastern Harbour (E.H.) of Alexandria, Egypt. Fifty five species of phytoplankton were identified and represented different distinct classes “Bacillariophyceae; Dinophyceae, Chlorophyceae, Cyanophyceae and Eugelenophyceae”. Also, Diatom formed the most dominant group. The average number of the phytoplankton density varied from 4.8 × 104 to 1.1 × 106 cell l-1 during the study period and Skeletonema costatum was the agent causing the red tide. The existence percentages of bacteria ranged from 2.6 to 17.9% on all media tested. The bacterial isolates on the nutrient agar medium represented the highest existence with a total percentage of 43.6%, followed by MSA medium (25.7%), while the lowest percentage was for the AA medium at 7.8%. However, twelve isolates were selected as representative for bacterial community during study interval. Based on the morphological, biochemical, physiological and enzymatic characteristics, the bacterial strains were described. Depending on the 16S rDNA gene sequence, three common antagonists were aligned as: Vibrio toranzoniae strain Vb 10.8, Ruegeria pelagia strain NBRC 102038 and Psychrobacter adeliensis strain DSM 15333. The interaction between these bacteria and S. costatum was studied. The growth of S. costatum was significantly lower whenever each bacterium was present as compared to axenic culture. More specifically, 30% (v/v) of the all tested bacteria showed the strongest algicidal activities, as all S. costatum cells were killed after two days. 10% of R. pelagia and P. adeliensis also showed significant algicidal activities within six days.  相似文献   

9.
As a major aldehyde pollutant widely existing in industry and our daily life, acetaldehyde is more and more harmful to human health. As characteristic habitat niche, bacteria from deep sea environments are abundant and distinctive in heredity, physiology and ecological functions. Thus, the development of acetaldehyde-degrading bacteria from deep sea provides a new method to harness acetaldehyde pollutant. Firstly, in this study,acetaldehyde-degrading bacteria in the deep sea water of the West Pacific Ocean were enriched in situ and in the laboratory respectively, and then the diversity of uncultured bacteria was studied by using 16 S r RNA genes. Then acetaldehyde-degrading strains were isolated from two samples, including enrichment in situ and enrichment in laboratory samples of deep sea water from the West Pacific Ocean using acetaldehyde as the sole carbon source,and then the ability of acetaldehyde degradation was detected. Our results showed that the main uncultured bacteria of two samples with different enrichment approaches were similar, including Proteobacteria,Actinobacteria, Firmicutes, Cyanobacteria, but the structure of bacterial community were significant different.Four subgroups, α, γ, δ and ε, were found in Proteobacteria group. The γ-Proteobacteria was dominant(63.5%clones in laboratory enriched sample, 75% clones in situ enriched sample). The species belonged to γ-Proteobacteria and their proportion was nearly identical between the two enrichment samples, and Vibrio was the predominant genus(45% in laboratory enriched sample, 48.5% in situ enriched sample), followed by Halomonas(9% in situ enriched sample) and Streptococcus(6% in laboratory enriched sample). A total of 12 acetaldehyde-degrading strains were isolated from the two samples, which belonged to Vibrio, Halomonas,Pseudoalteromonas, Pseudomonas and Bacillus of γ-Proteobacteria. Strains ACH-L-5, ACH-L-8 and ACH-S-12,belonging to Vibrio and Halomonas, have strong ability of acetaldehyde degradation, which could tolerate 1.5 g/L acetaldehyde and degrade 350 mg/L acetaldehyde within 24 hours. Our results indicated that bacteria of γ-Proteobacteria may play an important role in carbon cycle of deep sea environments, especial the bacteria belonging to Vibrio and Halomonas and these strains was suggested for their potentials in government of aldehyde pollutants.  相似文献   

10.
The composition, structure, and distribution of flora and fauna on hydraulic facilities in the cooling system of the Vladivostok combined heat and power plant-2 were studied in summer and autumn of 2001. Cluster analysis was applied to differentiate Balanus rostratus, Mytilus trossulus, Jassa marmorata, Crassostrea gigas + Balanus rostratus, Modiolus modiolus + Pachycheles stevensii, Hydroides ezoensis, and Amphibalanus improvisus communities. The groups of fouling organisms found on the studied objects were shown to be assigned both to “physically controlled” and “biologically balanced” benthic communities. This study stresses the high similarity between the fouling communities of anthropogenic substrata and natural intertidal and subtidal benthic communities from adjacent areas of Peter the Great Bay.  相似文献   

11.
The species compositions of the genus Chironomus in the Curonian and Vistula lagoons are very similar, represented by Ch. plumosus and Ch. balatonicus. In the Curonian Lagoon, in addition to these two species, Ch. muratensis and the first-generation interspecific hybrid Ch. muratensis × Ch. plumosus are also found. In this lagoon, Ch. plumosus occurs most frequently (84%); Ch. balatonicus is considered a subdominant species (24%). In the Vistula Lagoon, on the contrary, the high frequency of occurrence is typical of Ch. balatonicus (89%); for Ch. plumosus, it reaches only 11%. The Ch. plumosus population occupies most of the Curonian Lagoon; Ch. balatonicus is present only in its northern part, from the village of Juodkrante to the city of Klaipeda. In the Vistula Lagoon, Ch. balatonicus is distributed over almost its entire area, while Ch. plumosus is found locally, only near the mouth of the Nogat River. The distribution of the sibling species in the lagoons is determined by the salinity gradient.  相似文献   

12.
The feeding of abundant herbivore plankton species has been investigated during different stages of coccolithophorid development in the northeastern Black Sea, namely, at the initial stage of development (March 2009) and at the massive bloom stage (June 2011 and May 2013). The role of coccolithophorids as a food source for Black Sea copepods Calanus euxinus, Acartia clausi, and Pseudocalanus elongatus; the heterotrophic dinoflagellate Noctiluca scintillans; and the larvacean Oikopleura dioica has been characterized for the first time. The contribution of coccolithophorids to copepod ration was low (0.2 to 13% of total carbon intake) during all study periods. The content of these organisms in the diet of N. scintillans ranged from 17 to 100%. The coccolithophorid bloom apparently had a stronger positive effect on the nutrition of fine filter feeders, such as N. scintillans and O. dioica, than on copepod nutrition. Daily coccolithophorid consumption by zooplankton ranged from 0.7 to 39.4% of the biomass in different study periods. The grazing of N. scintillans and O. dioica populations made the greatest contribution to coccolithophorid consumption (up to 26 and 23% of the coccolithophorid biomass, respectively).  相似文献   

13.
This study aims to evaluate the subacute toxic effects of oil under different treatments on marine organism by simulating natural contaminative processes. In this study, 120# (RMD15) fuel oil was selected as the pollutant and marine medaka (Oryzias melastigma) embryos as the experimental organism. The developmental toxicity of different volume concentrations (0.05%, 0.2%, 1% and 5%) of water-accommodated fractions, biologically-enhanced water-accommodated fractions, and chemically-enhanced water-accommodated fractions on the embryos in different exposure time (8, 15 and 22 d) were compared and the content of relevant polycyclic aromatic hydrocarbons (PAHs) was studied (in dispersion and in vivo). The subacute toxic effects were assessed in terms of antioxidant activities of enzymes (superoxide dismutase, catalase and glutathione S-transferase) and the blue sac disease (BSD) indexes.The results showed that the BSD indexes of the treatment groups were significantly higher than the respective control groups and showed positive correlations with both concentration and exposure time. The experiments with three antioxidant enzymes indicated that enzymatic activities of the embryos changed dramatically under the oxidation stress of petroleum hydrocarbons, especially after adding the dispersants. With the increase of petroleum hydrocarbon concentration and exposure time, the three enzymes showed different degrees of induction and inhibition effects.  相似文献   

14.
The distribution of chaetognaths was investigated at 10 stations in the southern part of Korean waters (line S), at six stations in the eastern part of Korean waters (line E) and at 8 stations in the western part of Korean waters (line W). Ten species were present at the stations at line S and Flaccisagitta enflata and Zonosagitta bedoti were dominant among these species. Mean densities at line S ranged from 7 inds.m-3 to 27 inds.m-3. Five chaetognath species were found at the stations at line E and Zonosagitta nagae and Parasagitta elegans were the most abundant. Mean densities ranged from 1 to 10 inds.m-3. Four chaetognath species were present at line W and Aidanosagitta crassa and chaetognath juveniles were dominant in this line. Mean densities ranged from 21 to 199 inds.m-3. The density of chaetognaths was highest at line W while the diversity of chaetognaths was highest at line S. Individuals of chaetognaths were divided into two groups, a group of line E and a mixed group of lines W and E. This study suggests that F. enflata is a warm water species; Z. nagae is a mixed water species; P. elegans is a cold water species; and A. crassa is a less saline water species. The mtCOI of F. enflata, which was a dominant species in the sampling area, was analyzed. F. enflata that are present in waters around Korean were genetically divided into two groups, which may be influenced by various oceanic factors.  相似文献   

15.
Despite its potential significance for industrial utilization, any activities associated with the mining of manganese (Mn) nodules might have substantial impacts on benthic ecosystems. Because microorganisms respond quickly to changing environmental conditions, a study of microbial communities provides a relevant proxy to assess possible changes in benthic ecosystems associated with mining activities. We investigated fine-scale microbial community composition and diversity inside and on the surface of Mn nodules and in nearby deep-sea sediments in the Korea Deep Ocean Study (KODOS) area located in the Clarion-Clipperton Fracture Zone (CCFZ) of the northeast equatorial Pacific. Although microbial cell density was lower within nodules (3.21 × 106 cells g-1) than in sediment (2.14 × 108 cells g-1), nodules provided a unique habitat for microorganisms. Manganese-oxidizing bacteria including Hyphomicrobium and Aurantimonas in Alphaproteobacteria and Marinobacter in Gammaproteobacteria were abundant in nodules, which implied that these bacteria play a significant role in nodule formation. In contrast, Idiomarina in Gammaproteobacteria and Erythrobacter and Sulfitobacter in Alphaproteobacteria were abundant in sediments. Meanwhile, Thaumarchaeota, a phylum that consists of ammonia-oxidizing chemolithoautotrophs, were the predominant archaeal group both in nodules and sediment. Overall, microbial communities in Mn nodules were unique compared to those observed in sediments. Furthermore, the phylogenetic composition of microorganisms in the KODOS area was distinguishable from that in the nodule provinces claimed by China and Germany in the CCFZ and nodule fields in the central South Pacific Gyre, respectively.  相似文献   

16.
Seven species of Pleuronectidae (Platichthys stellatus, Kareius bicoloratus, Pseudopleuronectes herzensteini, Microstomus achne, Glyptocephalus stelleri, Hippoglossoides dubius, and Limanda punctatissima) were identified based on eggs collected from the western margin of the East Sea (east coast of Korea), using DNA barcoding. The eggs of P. herzensteini and G. stelleri were relatively widely distributed along the east coast of Korea, whereas those of P. stellatus and K. bicoloratus were narrowly distributed; in particular, the eggs of P. stellatus were restricted to areas near bays. The eggs, which share common morphological characteristics (such as a homogeneous yolk and smooth membrane) were divided into three groups according to egg size: group A (more than 1.60 mm in egg diameter, including genera Hippoglossoides and Microstomus), group B (1.00–1.60 mm, including genera Kareius, Glyptocephalus, and Platichthys), and group C (less than 1.00 mm, including genera Limanda and Pseudopleuronectes). This paper provides an overview of the morphological characteristics of the eggs of the family Pleuronectidae collected from the east coast of Korea. Our approach to the analysis of eggs, based on DNA barcoding, morphological characteristics, and geographic distributions, provides a rapid and accurate basis for identifying spawning areas and spawning periods, thus facilitating the assessment and management of fisheries stocks and resources.  相似文献   

17.
A study on the reproductive cycle of the blood cockle Anadara granosa (Bivalvia: Arcidae) was conducted at three different areas in the northern region of the Strait of Malacca. A total of 1,920 samples of adult A. granosa (38–71 mm length) were collected from June 2009 until September 2010. Qualitative techniques (gonadal microscopic fresh smear test and histology analysis) as well as quantitative techniques (analysis of condition index and gonadal index) were used to predict monthly gonadal development stages of A. granosa. The gonadal index of A. granosa from Banda Aceh (Indonesia) (r = 0.469, P > 0.05) and Pulau Pinang (Malaysia) (r = 0.123, P > 0.05) did not show any correlation to their condition index, whereas the gonadal index of A. granosa from Lhokseumawe (Indonesia) (r = 0.609, P < 0.05) showed moderate positive correlation to the condition index. During the 16 month sampling period, four reproductive cycles were observed: each from three to six months. The process of releasing gametes is termed dribble spawning, and is the same in all populations. The principle component analysis (PCA) indicated that A. granosa reproduction was affected by interaction between internal physiological factors and indigenous environmental factors. In all sampling areas, phytoplankton density played a key role in the reproductive cycle in A. granosa. Information on the reproductive biology of this species is essential for species management and to improve the sustainability practices of the fisheries industry. These findings will provide basic information on the biology of the blood cockle A. granosa for stock management in the region.  相似文献   

18.
Macrobenthic fauna in an estuarine Gwangyang Bay, southern Korean coast, were investigated to uncover recent variations in their community structures. In the study area, macrobenthic faunal communities were mainly composed of polychaete worms which were the most abundant faunal group with the highest values in species number and density, while mollusks accounted for the highest proportion in total biomass. There was no clear seasonal difference in species richness during the two year period of the investigation, but the mean density and biomass increased every spring and summer due to the mass recruitment of Theora fragilis. The Shannon’s diversity index (H') was more than 2.0 during most sampling seasons and did not show any significant seasonal difference except for the data in August, 2011 when azoic conditions occurred. The community structures of macrobenthos in Gwangyang Bay did not show any remarkable change in the dominance of the two top dominant species, Scoletoma longifolia and Heteromastus filiformis, which abundantly occurred in all seasons, except for the abundance peaks associated with high occurrence of T. fragilis and Paraprionospio cordifolia, especially in spring and summer and in autumn, respectively. These fauna changes reflected the changes in the macrobenthic community health status in Gwangyang Bay, where stable conditions and a healthy status prevailed in winter, but a slightly disturbed status prevailed from spring to autumn.  相似文献   

19.
The estimated characteristics of the atmospheric boundary layer, obtained by the simulation of wind wave fields using three versions of the WAM numerical model are compared with the well-known empirical dependences of drag coefficient C d on wind speed U 10 and wave age A, as well as with the dependence of dimensionless roughness height z n on inverse wave age u*/с р. Calculations carried out for several years in the areas of the Pacific and Indian oceans, based on the ERA-interim and CFSR wind reanalyses have shown good agreement between the model and empirical dependences C d (U 10) and C d (A). The range of estimated variability for z n (u*/с р ) has been found to be significantly less than empirical. It has been also found that estimated values of wind speed U 10W (t) are overestimated from 5 to 10% in all versions of WAM models compared with the input wind reanalysis U 10R (t) at the moments of appearance maximum values of wind U 10R (t). The reasons for the established features of the WAM model and their dependence on the model version are discussed.  相似文献   

20.
Instead of approximation formula ln(E(t)/E(0)) = [(a ? bt)t/(c + T)] commonly used at present for representing dependence of pressure of saturated streams of liquid water E upon temperature we suggested new approximation formula of greater accuracy in the form ln(E(t)/E(0)) = [(A ? Bt + Ct 2)t/T], where t and T are temperature in °C and K respectively. For this formula with parameters A = 19.846, B = 8.97 × 10?3, C = 1.248 × 10?5 and E(0) = 6.1121 GPa with ITS-90 temperature scale and for temperature range from 0°C to 110°C relative difference of approximation applying six parameter formula by W. Wagner and A. Pruß 2002, developed for positive temperatures, is less than 0.005%, that is approximately 15 times less than accuracy obtained with the firs formula. Increase of temperature range results in relative difference increasing, but for even temperature range from 0°C to 220°C it does not higher than 0.1%. For negative temperatures relative difference between our formula and a formula of D. M. Murphy and T. Koop, 2005, is less than 0.1% for temperatures higher than ?25°C. This paper also presents values of coefficients for approximation of Goff and Grach formula recommended by IMO. The procedure of finding dew point T d for known water steam pressure e n based on our formula adds up to solving an algebraic equation of a third degree, which coefficients are presented in this paper. For simplifying this procedure this paper also includes approximation ratio applying a coefficient A noted above, in the form T d (e n ) = \(\frac{{AT_0 }}{{A - \varepsilon }}\) + 0.0866?2 + 0.0116?10/3, where ? = ln(e n /E(T 0)). Error of dew point recovery in this ratio is less than 0.005 K within the range from 0 to 50°C.  相似文献   

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