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1.
An analysis of spectra of wave disturbances with zonal wave numbers 1 ≤ k ≤ 10 is carried out using winter (November to March) ERA-Interim reanalysis geopotential data in the troposphere and stratosphere for 1979–2016. Contributions of eastward-traveling (E), westward-traveling (W), and stationary (S) waves are estimated. The intensification of wave activity is observed in the tropical troposphere and stratosphere and in the upper stratosphere of the entire Northern Hemisphere. The intensification of wave activity in the tropics and subtropics is noted for waves of all types (E, W, and S), while in the middle and higher latitudes it is related mainly to stationary and eastward waves. Near the subtropical tropopause, the energy of stationary waves has increased in recent decades. In addition, in the tropical and subtropical troposphere and in the subtropical lower stratosphere, the energy of the eastward-traveling waves in El Niño years may be one and a half times or twice the energy in La Niña years. The spectrally weighted zonal wave numbers for waves of all types (E, W, and S) are the largest in the upper subtropical troposphere. The spectrally weighted zonal wave number for W and S waves is correlated with the Atlantic Multidecadal Oscillation index and varies by 15% in 1979–2016 (on an interdecadal time scale). The spectrally weighted wave period is larger in the stratosphere than in the troposphere. It is maximal in the middle extratropical stratosphere. The spectrally weighted wave periods correlate with the activity of sudden stratospheric warmings. The sign of this correlation depends on the latitude, atmospheric layer, and zonal wave number.  相似文献   

2.
We study the space-and-time variability of the concentrations of 27 microelements (Sc, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Mo, Ag, Cd, Sn, Se, Sb, Ba, La, Ce, Sm, Eu, Tb, Hf, Hg, Pb, Au, Th, and U) and Sr in the sea, river, and waste waters of the South Coast of Crimea in 2002–2007. Parallel with the data about elements studied earlier, we present, for the first time, the data of investigations of the contents of rareearth elements (Lu, Nd and Yb) whose concentrations in the major part of the analyzed samples of seawater were lower than the limit of their quantitative determination. We present the ranges of the concentrations of elements and perform their comparison with the data of the previous period of monitoring.  相似文献   

3.
- Abundance of total bacteria, heterotrophic bacteria, coliform and oil degradable bacteria and their relations with salinity and suspended matter in the frontal waters in the Hangzhou Bay are described. The results obtained show that the highest abundances of total bacteria , heterotrophic bacteria are encountered around the front and near the northern shore of the Hangzhou Bay, where a positive correlation ( r =0. 70) between the total bacteria abundance and the total suspended matter (TSM) is persent. Moreover,the abundance of oil degradable bacteria being an indicator of oil pollution, is also high in that region.  相似文献   

4.
In this paper, numerical modelling of the fluctuation of the thermocline in the Bohai Sea has been made using a two-dimensional nonlinear model in stratified ocean and the model for the depth of the thermocline under the effects of wind stirring. The computed results depict the variations of the fluctuation of the thermocline driven by different kinds of wind fields. The fluctuation of the thermocline in the Bohai Sea varies somewhat with different directions, paths and locations of typhoon (cyclone). Under the effects of strong wind, the thermoclines both sink due to mixing and fluctuate. Furthermore, the fluctuation of the thermocline speeds up mixing. At last, the thermoclines disappear after 12-15 h when the strong wind increases from Force 6 to Force 9.  相似文献   

5.
This paper reports species composition, horizontal distribution and seasonal variation of total individual and dominant species of the Siphonophora and their relationship to the environmental factors. Materials from the water layers within 0~200 m were collected during the periods of September, 1983, April and May, July and August, and December, 1984 in the study region (12°-19°30′N, 111°-118°E, Fig. 1).  相似文献   

6.
The Pelotas Basin is the classical example of a volcanic passive margin displaying large wedges of seaward-dipping reflectors (SDR). The SDR fill entirely its rifts throughout the basin, characterizing the abundant syn-rift magmatism (133–113 Ma). The Paraná–Etendeka Large Igneous Province (LIP), adjacent to west, constituted the pre-rift magmatism (134–132 Ma). The interpretation of ultra-deep seismic lines showed a very different geology from the adjacent Santos, Campos and Espírito Santo Basins, which constitute examples of magma-poor passive margins. Besides displaying rifts totally filled by volcanic rocks, diverse continental crustal domains were defined in the Pelotas Basin, such as an outer domain, probably constituted by highly stretched and permeated continental igneous crust, and a highly reflective lower crust probably reflecting underplating.The analysis of rifting in this portion of the South Atlantic is based on seismic interpretation and on the distribution of regional linear magnetic anomalies. The lateral accretion of SDR to the east towards the future site of the breakup and the temporal relationship between their rift and sag geometries allows the reconstitution of the evolution of rifting in the basin. Breakup propagated from south to north in three stages (130–127.5; 127.5–125; 125–113 Ma) physically separated by oceanic fracture zones (FZ). The width of the stretched, thinned and heavily intruded continental crust also showed a three-stage increase in the same direction and at the same FZ. Consequently, the Continental-Oceanic Boundary (COB) shows three marked shifts, from west to east, from south to north, resulting into rift to margin segmentation. Rifting also propagated from west to east, in the direction of the final breakup, in each of the three segments defined. The importance of the Paraná–Etendeka LIP upon the overall history of rupturing and breakup of Western Gondwanaland seems to have been restricted in time and in space only to the Pelotas Basin.  相似文献   

7.
Abstract-A survey was carried out in the central and north part of the Huanghai Sea (34.5°~37.0°N, 120.5°~124.0°E) during June 12~27, 2000. It was found that the abundance of marineflagellate ranged from 45 to 1278 cell/ml, 479 cell/ml in average. Flagellate was more abundant in thecentral part than in the north part of Huanghai Sea, and the abundance decreased with the increasingdistance from the coast, showing a similar distribution pattern with isotherm. Vertically, high densityof flagellate was always presented in the bottom of thermocline, and formed a dense accumulation in thecentral area of the Huanghai Sea Cold Water Mass. The effects of physical and biological factors on thedistribution of marine flagellate in early summer were discussed. Water temperature (especially the ex-istence of thermocline) rather than salinity showed significant effect on the distribution pattern of marineflagellate in the Huanghai Sea in early summer. When comparing the abundance of marine flagellatewith that o  相似文献   

8.
To determine recent interannual variations in the planktonic ecosystem of the slope water south of Japan, an area between 1000 m isobath on the continental slope and assumable Kuroshio front, in reference to preceding reports on the Kuroshio, we examined interannual variations of physical factors, sea surface chlorophyll concentration (SSChl), size-fractioned copepod biomass and the abundance of Calanus sinicus, one of the dominant copepods in the region, in February from 1990 to 2002. In the slope water, SSChl concentration had generally shown a higher value than in the Kuroshio and increase of the SSChl in both areas started in February but lasted longer in the slope water. The regional distribution of copepod biomass and C. sinicus abundance was similar to that of phytoplankton in that they were distributed more densely in the slope water than in the Kuroshio, reflecting assumed higher nutrient supply. The interannual variation in sea surface temperature in the slope water was explained by the rise of air temperature in 1998, a strong El Niño year, and subsequent change in the Kuroshio path (1999–2001). The interannual variation of the planktonic community, i.e. sea surface chlorophyll concentration and copepod biomass, was attributed to the effects of those physical events through the direct effect of local temperature and/or variation in surface irradiance, except for a prominent increase of copepods in the slope water in 2000. The effect of interannual change in the vertical mixing, suggested in previous studies, was not apparent in February, when the primary production is not limited by nutrient concentration which would be more important in regulating biological production in later months.  相似文献   

9.
An analysis of the structural and functional characteristics of zooplankton community and their coupling with the synoptic situation was carried out for the spring period in the northern Sea of Okhotsk. The years of 2000 and 2001 may be referred to as “cold” type due to the significant extent of the ice-covered area. Based on the ice cover extent, the years of 2004 and 2005 may be referred to as “warm” years due to the decreased extent of the ice-covered area. The “cold” and “warm” years did not significantly differ from each other in terms of the total zooplankton biomass. In the northeast Sea of Okhotsk, the zooplankton abundance increased during the “cold” years, while, in its northwestern part, the zooplankton abundance increased during the “warm” years. The different types of years significantly differ in the species structure of the macrozooplankton community. The abundance of copepods was higher in the “warm” years, whereas the chaetognath abundance increased in the “cold” ones. These features of the dynamics and distribution of zooplankton in the northern part of the Sea of Okhotsk also affected its productivity. The higher production of the elements of the zooplankton community that was revealed in the “warm” years was caused by the increase in the seasonal P/B ratio of both nonpredatory and predatory species. In the “warm” years, the production of nonpredatory zooplankton was higher in the northwest, while, in the “cold” years, it was higher in the northeast of the area.  相似文献   

10.
In this study, the inverse method is used to compute the Kuroshio in the East China Sea and southeast of Kyushu and the currents east of the Ryukyu Islands, on the basis of hydrographic data obtained during September-October, 1987 by R/V Chofu Maru. The results show that: (1)A part of the Taiwan Warm Current has a tendency to converge to the shelf break; (2) the Kuroshio flows across the section C3 (PN) with a reduced current width, and the velocity of the Kuroshio at the section C3 increases and its maximum current speed is about 158 cm/s, and its volume transport here is about 26×106m3/s; (3) the Kuroshio has two current cores at the sections C3 (PN) and B2 (at the Tokara Strait); (4) the currents east of the Ryukyu Islands are found to flow northward over the Ryukyu Trench during September-October, 1987. The velocities of the currents are not strong throughout the depths. At the section C2 east of the Ryukyu Islands, the maximum current speed is at the 699 m levei and its magnitude is 25 cm/s, and i  相似文献   

11.
INTRODUCTIONInordertostudythemarinesedimentationoftheChukchiSeaandBeringSeaandgathertheinformationofpaleoceanographyandpaleoenvironment,theFirstChineseNationalArcticResearchExpeditionTeamcollectedbenthonicmolluscansamplesintheChukchiSea ,BeaufortSeaandBeringSeafromJuly 1sttoSeptember 9th ,1 999byicebreakerXuelong .ItwasnotonlythefirstsamplingthatChinesescientistscollectedmolluscaremainsinabove mentionedar eas,butalsooneofinvestigationsinasinglecruisewithhighersamplingrateandalotofb…  相似文献   

12.
The behavior of the vertical aerosol structure (profiles of the ratio of the coefficients of the backward total and molecular scattering) in the height interval 30–80 km is analyzed from the results of lidar observations in Kamchatka over the period from October 2007 through December 2009. The obtained data revealed a regular two-layer aerosol structure in this height range with the maxima of the ratio of the scattering coefficients in the upper stratosphere at heights 35–50 km and in the mesosphere at heights of 60–75 km, as well as a relation between seasonal variations in the aerosol stratification and the circumpolar vortex affecting dynamic processes in the atmosphere of midlatitudes. The procedure of including the aftereffect of the Hamamatsu-M8259-01 PEM, which influences the error in the calculation of the ratio of scattering coefficients, is described.  相似文献   

13.
Concerning the ecological studies of the Hydromedusae and Ctenophores in Taiwan Strait, we have only two papers available on these studies in the southwest of Taiwan Strait. Throughout the western Taiwan Strait, for the first time the paper reports species composition, seasonal change, hori zontal distribution, ecological characteristics of the Hydromedusae and Ctenophores and their relationship to the environmental factors.  相似文献   

14.
Some numerical experiments have been developed to explain dynamically the mechanism of the formation of the wintertime circulation in the Northern Huanghai Sea and the Bohai Sea. From the results of the numerical experiments with Coriolis parameter having positive and negative values respectively, it is found that the current pattern characterized by flowing into the Bohai Sea in the northern part of the Bohai Straits and flowing out of the Bohai Sea in the southern part of the Bohai Straits is controlled basically by the bottom topography with "the deepness on the northern side and shallowness on the southern side'in the Bohai Straits, and is not related to Coriolis parameter having positive and negative values. It also shows that the Huanghai Warm Current regarded as the inllow condition passing through the in-ports at the water boundary of the numerical experiments only influences the region near the water boundary and the eastern region of the Northern Huanghai Sea. In addition, the mechanism of the  相似文献   

15.
A digital database on the seismostratigraphy of the oceanic crust of the northeastern part of the Indian Ocean is compiled. In the first layer of the crust, the interval seismic wave velocities are 3.02 ± 0.16 km/s; in the second layer, they equal to 5.31 ± 0.27 km/s; and, in the third layer, the values are 6.46 ± 0.30 km/s. The bottom of the third seismic layer is represented by mantle rocks with an average velocity of 8.10 ± 0.16 km/s. Schemes of the distribution of the thicknesses of the second and third layers of the oceanic crust, of the total thickness of the crust, of the surface of the basement, and of the Mohorovicic discontinuity for the area considered are presented. The schemes compiled allow one to update and complement the ideas about the configuration of the major tectonic structures of the area.  相似文献   

16.
1Introduction Besidestheprecipitationandriverdischarges,the watersinthePacificOceanandtheAtlanticOceanare thesourcesoftheArcticOceanwater.TheAtlantic waterenterstheArcticOceanviatheFramStraitand theBarentsSea.Foritsdenserfeatureduetohigh salinity,mostofitsinkstothenorthofSvaldbardand circulatesinallthedeepbasinsintheArcticOcean, formingthedeepandbottomwatersoftheArcticO- cean(Aagaardetal.,1985;Rudelsetal.,1999).The BeringStraitistheonlychannelforthePacificwater toflowintotheArcticOce…  相似文献   

17.
On the basis of the experimental data accumulated in 1998–2005, we analyzed the space and time variations of the carbonate system of waters and the content of organic carbon in bottom sediments of the Sevastopol Bay. The intensity of gas exchange through the water-atmosphere interface was quantitatively estimated. It was shown that the partial pressure of carbon dioxide pCO2 in waters of the bay became much higher for the period of observations. The maximum changes were observed in summer. They were especially pronounced for the bottom layer of waters. For the entire period of observations, the invasion of carbon dioxide CO2 was predominant in the major part of the bay, and the content of organic carbon in the bottom sediments increased. The ability of waters in the bay to absorb CO2 is explained by the synthesis of organic substances, which becomes possible due to the presence of the equivalent load of nutrients. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 57–67, March–April, 2008.  相似文献   

18.
Role of mangrove in mercury cycling and removal in the Jiulong Estuary   总被引:4,自引:0,他引:4  
Baseline of mercury in mangrove swamp The mercury content in sediments in the Jiulong Estuary was determined in 1984 and 1985(Table 1). The highest content of mercury in sediments (300×10~(-9)) was found in Ditou, contrast-ing strongly with the low content of 36×10~(-9) in Port Dongzhai in the Hainan Island. Tab1e 1 showsthat the average content of mercury in sediments in the Jiulong Estuary is 140×10~(-9) and the averageof four areas is 72×10~(-9). This value means that these areas have not been heavily contaminated by  相似文献   

19.
In December–January of 2010 the spatial distribution of the phytoplankton production characteristics was studied along transects in the vicinity of the Greenwich meridian (I) and in the Drake Passage (II). On transect I, the surface chlorophyll a concentration and primary production varied from 0.11 up to 3.57 mg/m3 and from 4.38 up to 37.47 mgC/m3 per day, respectively. The chlorophyll a in the photosynthetic layer and the integrated primary production varied from 10.7 up to 66.1 mg/m2 and from 83 to 646 mgC/m2 per day, respectively. On transect II in the surface layer, the chlorophyll a concentration changed within the range of 0.09–1.02 mg/m3 and the primary production ranged from 2.08 to 9.49 mgC/m3. The integrated values ranged from 6.32 to 38.29 mg/m2 and from 41 to 221 mgC/m2 per day, respectively. The moderate means of themaximum quantum yield (F v/F m) on transects I and II (0.41 and 0.35, respectively) testify to the low activity of the phytoplankton’s photosynthetic apparatus. The studied water areas in the Southern Ocean differed both in the phytoplankton biomass expressed in the chlorophyll a concentration values and in the conditions of the primary production formation.  相似文献   

20.
INTRODUcrIO\The Arctic plays a tyP1cal role 1n regulating the global climate. AlthOugh it is 1ocated inthe high latitude with extremely low temperature similar to that of the isolated continent of theAntarctic, it is surrounded by land where Eskimo lives. The stirrounded land of North Pole be-longs to the tetritory of me countries of EuroPe, Asia and North AInerica. Thus ecologicaland natural enviroament in the AIctic and sub--arctic area has much closer interactions withrnankind cor…  相似文献   

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