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1.
Periodical surface currents with the periods of 46.5, 61, and 91 days detected from the satellite data in the Tatar Strait and Sakhalin Bay are presented as an effect of the Amur River runoff transformation in the estuary. The estuary transforms the flow as a flip-flop directing the Amur runoff by turns to the Sea of Japan or to the Sea of Okhotsk. The flip-flop period is six months. From May 23 to November 10, the Amur River flows into the Sea of Okhotsk and from November 10 to May 25, into the Sea of Japan.  相似文献   

2.
The seasonal variability of oceanographic conditions in the southern part of the Sea of Okhotsk is described based on long-term mean temperature T and salinity S from observations along a standard oceanographic section Cape Aniva-Cape Dokuchaev (May–November). It is shown that the Soya Current is relatively weak in spring, with low temperature and salinity gradients along the section. The Sea of Okhotsk low-salinity water mass is observed in the upper layer. It was formed as a result of melting of a large amount of ice brought here with the East Sakhalin Current from the northwestern part of the Sea of Okhotsk. A cold intermediate layer (CIL) at depths of 50–150 m extends along the entire section. The cold intermediate layer core with a temperature at the edge of the Sakhalin shelf of about ?1.3°C is retained during a period of maximum warming in August; however, in October–November the intensified flow of the East Sakhalin Current (up to 50 cm/s) results in a situation when relatively warm low-salinity waters, connected with the Amur River runoff, dissipate CIL. The results of 12 surveys conducted by the Sakhalin Research Institute for Fisheries and Oceanography in 1998–2004 show significant deviations of T and S [10] in different years from the calculated values. Generally, maximum anomalies (ΔT > 4°C and ΔS > 0.55‰) are observed in the surface layer. Their values and statistical significance decrease with depth. However, the situation is opposite in some cases. The maximum deviation from normal was observed in June 1999, when warm and salt waters were located much further seaward from the Kunashir shelf, which is most likely connected with the Soya Current meandering.  相似文献   

3.
Seasonal variations of hydrological conditions in the area adjoining the southeastern coast of Sakhalin Island are described based on the analysis of monthly mean temperature and salinity obtained over standard oceanic sections Makarov-Cape Georgii and Cape Svobodny-the sea and from nine oceanic surveys. The Poronai River runoff that promotes the formation of a warm surface layer with low salinity largely influences the water area of Terpeniya Bay in the northern part of the area studied. In spring, these waters primarily spread southward along the coast; in summer, they flow southeastward, forming a weak vortex structure at 144° E. In the fall, major changes occur below 20 m, where waters of the cold intermediate layer are replaced by warmer waters (4–6°C) of low salinity connected with the Amur River runoff. The destruction of the CIL core near the shelf edge at depths of about 100 m resulting from the fall intensification of the East Sakhalin Current is pronounced in the southern, abyssal part of the region. The coastal area is covered by waters with salinity below 32‰ connected with the Amur River runoff. The volume of low-salinity waters coming through the Cape Svobodny-the sea section into the southern part of the Sea of Okhotsk is estimated at 3000 km3 taking into account instrumental measurements of flow rates.  相似文献   

4.

Based on the numerical simulation of water circulation in the Sea of Okhotsk in 1986 to 2015, the impact of deep cyclones on the circulation off the northeastern coast of Sakhalin is studied. The circulation in the Sea of Okhotsk is simulated with the COSMO-Ru-INMOM-CICE model configuration, where the COSMO-Ru and INMOM resolve explicitly the mesoscale atmosphere and ocean dynamics and the CICE resolves the ice cover evolution. The extreme atmospheric events associated with the intensive cyclone activity over the Sea of Okhotsk during the cold season are classified. It is found that high velocity is typical of the cyclones coming to the sea from Sakhalin, and wind speed on the periphery is higher for the cyclones coming to the Sea of Okhotsk from the south and southwest. The analysis of water circulation response off the northeastern coast of Sakhalin demonstrates that the meridional current velocity on the shelf increased by several times from the sea surface to the bottom for all types of cyclones. On the edge of the shelf, southern currents intensified in the surface and bottom layers during the passage of cyclones and at the intermediate depths during the passage of fronts. On the continental slope, southern currents intensified in the surface, intermediate, and bottom layers depending on the type of extreme events.

  相似文献   

5.
Data of long-term observations at three standard oceanographic sections are analyzed. A complex pattern of seasonal variability of oceanographic conditions off the southwestern coast of Sakhalin Island is studied. It is shown that the cold West Sakhalin Current directed to the south is observed from May to October; the low-salinity cold flow of the Sea of Okhotsk water oriented to the north is recorded from November to March. The northern boundary of penetration of the Sea of Okhotsk water is identified.  相似文献   

6.
The first baroclinic Rossby radius of deformation (R 1) in the Sea of Okhotsk is estimated using the hydrological datasets from the World Ocean Atlas (WOA) 2001 and WOA 2013. It is established that the maximum values of R 1 are observed over the Kuril Basin (18–20 km), and its minimum values (1.5–2 km), over the northern shelf of the Sea of Okhotsk. In the central part of the sea R1 varies from 8 to 10 km. The seasonal variability of R1 for both datasets is characterized by the minima in winter and by the maxima in summer. It was found that on the eastern shelf of Sakhalin Island R 1 reaches the maximum both in November (～6 km) and in April (～4-5 km). According to the obtained estimates of R 1, the model grid resolution of 3 to 8 km should be used for the eddy-permitting numerical simulation of circulation in the Sea of Okhotsk, and the model grid resolution from 1.5 to 2 km, for the explicit simulation of mesoscale variability.  相似文献   

7.
Two opposite Far East monsoon summer seasons over the Amur River basin are investigated which caused the extreme drought and fires in 2008 and catastrophic flood in 2013. It is shown that in the low-water summer of 2008 due to blocking processes, polar-front cyclones were almost absent over the Amur, were short, had fuzzy frontal systems, and did not bring precipitation. The summer monsoon circulation was suppressed, and in the Amur region continental air masses dominated over marine tropical air. On the contrary, the summer of 2013 was characterized by unprecedented cyclonic activity and the sharp strengthening ofthe moisture-laden monsoon flow from the ocean. As a result, the intensification of summer monsoon precipitation and the Amur flood were observed. It was established that the Far East summer monsoon anomalies are associated with the large-scale transformation of atmospheric circulation over the Asia-Pacific region.  相似文献   

8.
Data of field observations are indicative of the periodic appearance of intrusions of cold water at depths of 250–400 m near the northeastern Sakhalin continental slope in summer. Monitoring of the oceanographic conditions in the area shows that the density contrast between shelf and offshore waters persists throughout the year. The static instability of the water column in the vicinity of shelf break and the continental slope is a permanent feature of the area during the year and is the main cause of ventilation of the Sea of Okhotsk water in summer. The energy of tides can be an additional drive for the penetration of shelf waters into the sea interior and modulate the ventilation process.  相似文献   

9.
An average long-term distribution of temperature and salinity is analyzed for different months (May–November) computed on the basis of materials accumulated at standard oceanological sections of the northern part of the Tatar Strait. The main attention is paid to the section Korsakov Cape-Cape Syurkum crossing the water area under study practically in the middle. In early spring, the cold waters with salinity of more than 33‰ are registered at the section Korsakov Cape-Cape Syurkum. The waters with smaller salinity are revealed only in late spring, in June. In the same period, the intensification of cold intermediate layer occurs, first of all, in the western part of the section. The waters in the surface layer near the Sakhalin coast are warmed more than at the continental shelf. During the summer, this difference gradually decreases and the surface layer temperature becomes even in September. On the contrary, the spatial salinity gradients increase. In the fall, under the influence of northern and northwestern winds being typical of this period, the upwelling is formed near the Sakhalin coast and the cold dense waters emerge in the narrow coastal strip. The direction of alongshore flow changes from northern to the southern one. At the section Korsakov Cape-Cape Syurkum in November, the influence of small-salinity waters associated with the Amur River runoff is significantly revealed.  相似文献   

10.
Considered are the synoptic mechanisms of the catastrophic flood formation on the Amur River in summer 2013; these enabled revealing the set of reasons responsible for the unprecedented rise of the water level. Demonstrated is the primary importance of the series of polar-front cyclones of the unprecedented duration and intensity being the main circulation link of the summer Far Eastern monsoon. It is revealed that the intensification of monsoon rains is associated with the active participation of the marine tropical air from the Pacific Ocean in frontal processes. The simultaneous deepening of the monsoon low over the land and the strengthening of the subtropical high over the ocean became a reason for the dramatic intensification of the moisture-laden monsoon flow.  相似文献   

11.
Tendencies in climate change in the Amur River basin are generally synchronous to the global ones. During the last century, the annual mean temperature of surface air increased by 1.3°C, minimum warming being observed in the east part of the basin (0.6°C) and maximum one in the west part (1.7–2.5°C). The largest impact on the annual mean temperature growth comes from winter and spring temperature increase (2–4°C/100 years). During the last 30 years, the warming rate in the basin was 2–3 times higher than during the whole period of 1891–2004. Simultaneously with warming in the Amur River basin, annual and warm-season precipitation totals increased by 8 and 6%, respectively, during the 115-year period. The highest increase in precipitation totals occurs in cold season (29% during 115 years). During the last 30 years, together with intense warming in the Amur River basin, the annual precipitation totals are found to decrease by an average of 2.1%/10 years.  相似文献   

12.
The field data show that the ventilation of waters in the Sea of Okhotsk occurs the year round as a cyclic process and consists of several phases. During the initial phase, the shelf waters enter the offshore subsurface layers. Later, they appear at intermediate depths and spread southward as cold intrusions mixing with surrounding waters on their way. During the last phase of the cycle, the shelf waters do not penetrate the deep-sea layers, and in the vertical structure of temperature field near the northeast coast of Sakhalin, a local phenomenon of “warm” dichothermal layer is observed.  相似文献   

13.
The influence of interannual variability of water transport by the East Kamchatka Current, the Oyashio, and the East Sakhalin Current on the dissolved oxygen concentration in the western subarctic Pacific and the Sea of Okhotsk is considered for studying climate change impact on sea water chemical parameters. It is shown that statistically significant relation is observed between the calculated with the Sverdrup equation interannual variations in water transport with the East Kamchatka Current, the Oyashio, and the East Sakhalin Current and changes in mean sea water level at coastal stations in winter. It is found that the main reason of interannual variability of the dissolved oxygen concentration at isopycnic surfaces in the intermediate water layer (100–800 m) of the Sea of Okhotsk and in the western subarctic Pacific is caused by variations in water transport by the East Kamchatka Current, the Oyashio, and the East Sakhalin Current.  相似文献   

14.
Regional peculiarities of the direction of climate-related changes in the maximum and minimum river runoff in Russia in the 20th century, frequency and duration of dangerous inundations with economic damage, floods, mudflows as well as lack of water, and low-water periods are under consideration. It is found that for the first years of the 21st century, compared to the last decade of the 20th century, frequency and duration of hazardous inundations during high waters and floods increased in the Upper Ob and Kama river basins, during high waters, in the rivers of the Far East Primorye and Sakhalin, in the Northern Caucasus, the danger induced by mudflows and rain floods increased. In the Lena and Yenisey river basins, the flood hazard was preserved in the case of ice clogging. At the same time, in the Western Siberian, Trans-Baikal, the Amur, and Kolyma basins the frequency of periods with extremely shallow water significantly increased.  相似文献   

15.
Abstract

The action of tides on density‐driven circulation, internal gravity waves, and mixing was investigated in the St. Lawrence Estuary between Rimouski and Québec City. Time‐varying fields of water level, currents and density were computed under typical summer conditions using a three‐dimensional hydrostatic coastal ocean model that incorporates a second order turbulence closure submodel. These results are compared with current meter records and other observations. The model and the observations reveal buoyancy effects produced by tidal forcing. The semi‐diurnal tide raises the isopycnals over the sills at the head of the Laurentian Trough and English Bank, producing internal tides radiating seaward. Relatively dense intermediate waters rise from below 75‐m depth to the near surface over the sills, setting up gravity currents on the inner slopes. Internal hydraulic controls develop over the outer sills; during flood, surface flow separation occurs at the entrances of the Saguenay Fjord and the upper estuary west of Ilet Rouge Bank. Early during ebb flow (restratification), the surface layer deepens to encompass the tops of the sills. As the ebb current intensifies, the model predicts the formation of seaward internal jumps over the outer sills, which were confirmed from acoustic reflection observations. As the internal Froude number increases further, flow separation migrates up to sill height. As a result of these transitions, internal bores emanate from the head region one to two hours before low water. We find that the mixing of oceanic and surface waters near the sills is driven by the vertical shear produced during ebb in the channel south of Ilet Rouge, the shear produced in the bottom gravity flood currents, and, to a lesser extent, the processes over the sills.  相似文献   

16.
Characteristics of the atmospheric general circulation during the catastrophic floods over the Changjiang- Huaihe River Valley(CHRV)are investigated.There are two precipitation patterns over China in the CHRV flood years:the CHRV flood-whole country-wet(P1)pattern and the CHRV flood-south(north)side-dry (P2)pattern.The circulation analysis results show that there are obvious differences between the NH 500- hPa geopotential height fields of P1 and P2 precipitation patterns.The establishment of East Asia-Atlantic (EAA)correlation chain(the South China Sea(SCS)high-the Meiyu trough-the Okhotsk Sea high over East Asia)is a critical condition for excessive summer precipitation over the CHRV,while the European blocking high plays an important role in determining the precipitation pattern over China in the CHRV flood years.Besides,the relation between the EAA correlation chain and the sea surface temperature anomaly (SSTA)in the North Pacific is also studied.  相似文献   

17.
Extreme flood on the Danube River in 2006   总被引：2，自引：0，他引：2  
Causes and features of an extreme flood on the Danube River in spring and summer 2006 are considered. The water levels at some gauge stations on the Middle Danube and at most gauge stations on the Lower Danube exceeded maxima observed during previous 100–130 years. The flood on the Lower Danube lasted from March to July and led to widespread inundations and damage. The flood was caused by melt of large amounts of snow accumulated in the river basin during winter, very warm spring, and abundant rains. In recent decades, the occurrence frequency of extreme hydrological events on the Danube River (large spring-summer floods and catastrophic rainfall freshets) has increased.  相似文献   

18.
两类江淮大水的大气环流特征   总被引：5，自引：1，他引：5  
于淑秋  林学椿 《气象学报》2006,64(5):605-613
文中研究了江淮流域特大洪涝的环流特征。江淮流域洪涝年全国降水有两类分布型:即江淮流域大水年中国降水偏多型和江淮流域大水其南北降水偏少型。研究了这两类降水分布型的环流特征,结果指出:北半球500 hPa位势高度场有着显著的差异。东亚大西洋相关链的建立(南海高压、梅雨槽和鄂霍茨克海高压)是江淮流域多雨的重要条件,而欧洲阻塞高压的建立在全国降水分布型中起着重要的作用。进而研究了东亚大西洋相关链与北太平洋海温的关系。  相似文献   

19.
The seasonal distribution of hypoxia in the bottom waters of the Eastern Bosporus (the Peter the Great Gulf, the Sea of Japan) is analyzed based on long-term observational data (2006-2013). It is revealed that in summer the monthly mean concentration of oxygen in the bottom waters considerably decreased as compared to average long-term data. The minimum values of oxygen concentration were registered during four months, from July to October. It is demonstrated that the small values of oxygen concentration are mainly caused by the inflow of hypoxic water from the Amur Bay.  相似文献   

20.
California's primary hydrologic system, the San Francisco Estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Previous work has shown that a projected warming would result in a reduction of snowpack storage leading to higher winter and lower spring-summer streamflows and increased spring-summer salinities in the estuary. The present work shows that these hydrologic changes exhibit a strong dependence on elevation, with the greatest loss of snowpack volume in the 1300–2700 m elevation range. Exploiting hydrologic and estuarine modeling capabilities to trace water as it moves through the system reveals that the shift of water in mid-elevations of the Sacramento river basin from snowmelt to rainfall runoff is the dominant cause of projected changes in estuarine inflows and salinity. Additionally, although spring-summer losses of estuarine inflows are balanced by winter gains, the losses have a stronger influence on salinity since longer spring-summer residence times allow the inflow changes to accumulate in the estuary. The changes in inflows sourced in the Sacramento River basin in approximately the 1300–2200 m elevation range thereby lead to a net increase in estuarine salinity under the projected warming. Such changes would impact ecosystems throughout the watershed and threaten to contaminate much of California's freshwater supply.  相似文献   

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