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1.
Based on the long-term surveys in 1995?C2010, the influence of the variability of the winter conditions on the interannual dynamics of the content of dissolved oxygen was studied concerning the deep waters (the 40 m isobath line) of the eastern part of the Gulf of Finland. The content of oxygen varied within a wide range with a low-pronounced trend to a decrease during the considered period. All the processes affecting the aeration of deep waters, i.e., the advection of oxygen-depleted saline waters from the Baltic Sea and the intensity of the autumnal and winter mixing, correlated with the North Atlantic oscillation index, which determined the close positive correlation between this parameter and the oxygen content (r = +0.87). The hypoxic effects in the gulf were registered in the years of negative anomalies of the North Atlantic oscillation. The conclusion is reached that the deterioration of the oxygen conditions at the inner part of the Gulf of Finland during the late 20th-early 21st century is mainly caused by the large-scale variations in the atmospheric processes. 相似文献
2.
Wang Dehan 《海洋学报(英文版)》1988,7(1):57-67
The vertical distribution and seasonal variation of air temperature, humidity, static stability and Richardson number over Xisha Island are investigated based on 7-year records by means of time-altitude cross section, and harmonic and regression analyses. Mean data on height above sea level, air temperature, specific humidity, relative humidity and air density at standard-pressure surfaces are given respectively in terms of the annual average and the typhoon seasonal average of the South China Sea respectively. 相似文献
3.
1NTRODUcrIONThe bohai As is a seasonally ice-covered sea and is located in the lowest latitudes (37' -4l'N), where sea ice occurs. The bohai ffea is nearly enclosed by land in the south, the northand the west, and only connects to the Huanghai ffea through the bohai Strait in the east.The width of the strait is abeut l06 km. The boai ffea is very shallow basin with the meandepth of l8 m and the maximum depth of 78 m. The topography of the sea bottom and thecoastal regions has an importan… 相似文献
4.
E. M. Volodin N. A. Diansky A. V. Gusev 《Izvestiya Atmospheric and Oceanic Physics》2013,49(4):347-366
This paper presents results from a simulation of climate changes in the 19th–21st centuries with the Institute of Numerical Mathematics Climate Model Version 4 (INMCM4) in the framework of the Coupled Model Intercomparison Project, phase 5 (CMIP5). Like the previous INMCM3 version, this model has a low sensitivity of 4.0 K to a quadrupling of CO2 concentration. Global warming in the model by the end of the 21st century is 1.9 K for the RCP4.5 scenario and 3.4 K for RCP8.5. The spatial distribution of temperature and precipitation changes driven by the enhanced greenhouse effect is similar to that derived from the INMCM3 model data. In the INMCM4 model, however, the heat flux to the ocean and sea-level rise caused by thermal expansion are roughly 1.5 times as large as those in the INMCM3 model under the same scenario. A decrease in sea-ice extent and a change in heat fluxes and meridional circulation in the ocean under global warming, as well as some aspects of natural climate variability in the model, are considered. 相似文献
5.
Wen Yang Wenjia Hu Bin Chen Hongjian Tan Shangke Su Like Ding Peng Dong Weiwei Yu Jianguo Du 《海洋学报(英文版)》2023,(4):59-71
Climate change has affected and will continue to affect the spatial distribution patterns of marine organisms. To understand the impact of climate change on the distribution patterns and species richness of the Sciaenidae in China’s coastal waters, the maximum entropy model was used to combine six environmental factors and predict the potential distribution of 12 major species of Sciaenidae by 2050s under Representative Concentration Pathways(RCPs) 2.6 and 8.5. The results showed that the averag... 相似文献
6.
The wave climate at the Maui site off the west coast of the North Island and off the east coast of Great Barrier Island to the east of the North Island are examined. This is done by means of average wave spectra derived from a 2‐year database, acquired from Waverider buoy measurements made over 1980 and 1981. The average spectra provide information about the individual sea states which characterise the wave climate, and show that on average the sea state on the east coast is less energetic than it is on the west coast. Further, it is seen that this difference results largely from a dominant and persistent long‐period south‐westerly swell of 12.4 s period which is present at the Maui location but absent from the Great Barrier Island seas. 相似文献
7.
The statistical analysis of the secular hydrometeorological data sets revealed a particular El Niño impact on the climatic system of the Indian Ocean domain. The spatial distribution of the sequent anomalies showed prominent local effects depending on the climatic season as well. The El Niño signal turned out to be better visible within the considered fields during the transitional phases of the Indian monsoon, when its activity is rather weak, unstable, or even almost absent. The hints of certain phase shifts found to appear in the monsoon cycle coincided timely with the El Niño event. First of all, this concerns the hamper effect, which being applied to the wind stress field in the spring season leads to the later onset of the wet southwest monsoon, which is accompanied by a precipitation shortage over huge inhabited territories. During the northeast monsoon, the equatorial-tropic part of the domain is affected by El Niño in such a way that the eastern near surface air transport arises and after this the Winter Monsoon Equatorial Current notably increases its speed. Quantitative estimations showed that the El Niño signal’s relative energy in the Indian Ocean area is nearly an order of magnitude lower when compared to the total monsoon energy. This implies that the total impact of El Niño upon the Indian Ocean domain’s climate system could not lead to a fundamental change of its regime, as, for example, a reversal of the monsoon circulation. 相似文献
8.
《Ocean Modelling》2008,20(2):157-169
The dynamical link between mean state biases and dominant timescales of interannual variability is examined using the output from two state-of-the-art coupled model simulations, results from an ocean-only simulation forced with observed surface fields, and various observational data sets. The focus of this study is the relative role of the mean upper ocean density structure vs. anomalous wind forcing in controlling the spectral characteristics of tropical Pacific interannual variability. It is shown that an extensive South Pacific Convergence Zone (SPCZ) creates a potential vorticity (PV) barrier in the Southern Hemisphere similar to the one associated with the Intertropical Convergence Zone (ITCZ) in the Northern Hemisphere in both climate models. The PV barrier in the Southern Hemisphere strongly constrains the mean equatorward flow in the ocean model pycnocline, creating a “choke point” for the mean flow around 10°S. It is then examined whether the PV barrier can also limit the anomalous flow associated with mass recharge/discharge to/from the equatorial thermocline at interannual timescales. If the anomalous flow were impeded by the mean PV structure the meridional extent of the area involved in the mass recharge/discharge process would be narrower, leading to a shorter adjustment (and ENSO) timescale. Comparison of the two climate models, both of which have similarly erroneous PV structures in the southern tropical Pacific, but different interannual timescales, shows that the meridional extent of the anomalous meridional transport is primarily controlled by the latitudinal location of the wind stress curl anomalies, while the mean state bias in the Southern Hemisphere does not seem to have any significant influence. 相似文献
9.
James R. Garrison Jr. Alberto M. Mestas-Nu?ez Joshua R. Williams Luz M. Lumb 《Geo-Marine Letters》2012,32(3):241-250
A study of the evolution of North Padre Island (southern Texas Gulf Coast) dunes was carried out using LIDAR topographic data, dune vibracores through the center of the dunes, and grab samples of shoreface sand at four locations along a cross-shore profile. Grain-size analyses of the vibracores show vertical variations in shoreface sand deposition over decimeter depth intervals. A dune ridge growth model is introduced that describes the dune vertical accretion rate as a function of island progradation and freshwater lens expansion. This model allows indirect dating of the dune core samples based on a known island progradation rate (1?m/year), and height and spacing of the dunes calculated from the topographic data. A sand provenance model is also proposed that links the sand deposition in the dunes with sand sourced from various depths along the shoreface profile, depending on storm activity. We present evidence linking the changes in storm-sand deposition in the dune cores with yearly climatic fluctuations in the Gulf of Mexico associated with landfalling tropical storm activity in the period from 1942?C1965. This record of storm-induced sand variability is negatively correlated with El Ni?o-Southern Oscillation (Pacific) sea surface temperature variability, and positively correlated with North Atlantic decadal sea surface temperature variability. 相似文献
10.
A change in ecosystem types, such as through natural-vegetation-agriculture conversion, alters the surface albedo and triggers attendant shortwave radiative forcing (RF). This paper describes numerical experiments performed using the climate model (CM) of the Institute of Atmospheric Physics (IAP), Russian Academy of Sciences, for the 16th–21st centuries; this model simulated the response to a change in the contents of greenhouse gases (tropospheric and stratospheric), sulfate aerosols, solar constant, as well as the response to change in surface albedo of land due to natural-vegetation-agriculture conversion. These forcing estimates relied on actual data until the late 20th century. In the 21st century, the agricultural area was specified according to scenarios of the Land Use Harmonization project and other anthropogenic impacts were specified using SRES scenarios. The change in the surface vegetation during conversion from natural vegetation to agriculture triggers a cooling RF in most regions except for those of natural semiarid vegetation. The global and annual average RF derived from the IAP RAS CM in late 20th century is ?0.11 W m?2. Including the land-use driven RF in IAP RAS CM appreciably reconciled the model calculations to observations in this historical period. For instance, in addition to the net climate warming, IAP RAS CM predicted an annually average cooling and reduction in precipitation in the subtropics of Eurasia and North America and in Amazonia and central Africa, as well as a local maximum in annually average and summertime warming in East China. The land-use driven RF alters the sign in the dependence that the amplitude of the annual cycle of the near-surface atmospheric temperature has on the annually averaged temperature. One reason for the decrease in precipitation as a result of a change in albedo due to land use may be the suppression of the convective activity in the atmosphere in the warm period (throughout the year in the tropics) and the corresponding decrease in convective precipitation. In the 21st century, the effect that the land-use driven RF has on the climate response for scenarios of anthropogenic impact is generally small. 相似文献
11.
Farn Parungo Clarence Nagamoto Cecilia M. I. R. Girz Jeff Torgerson Zhou Mingyu 《海洋学报(英文版)》1995,14(2):201-207
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12.
Jochem I. Jongma Emmanuelle Driesschaert Thierry Fichefet Hugues Goosse Hans Renssen 《Ocean Modelling》2009,26(1-2):104-113
Melting icebergs are a mobile source of fresh water as well as a sink of latent heat. In most global climate models, the spatio-temporal redistribution of fresh water and latent heat fluxes related to icebergs is parameterized by an instantaneous more or less arbitrary flux distribution over some parts of the oceans. It is uncertain if such a parameterization provides a realistic representation of the role of icebergs in the coupled climate system. However, icebergs could have a significant climate role, in particular during past abrupt climate change events which have been associated with armada’s of icebergs. We therefore present the interactive coupling of a global climate model to a dynamic thermodynamic iceberg model, leading to a more plausible spatio-temporal redistribution of fresh water and heat fluxes. We show first that our model is able to reproduce a reasonable iceberg distribution in both hemispheres when compared to recent data. Second, in a series of sensitivity experiments we explore cooling and freshening effects of dynamical icebergs on the upper Southern Ocean and we compare these dynamic iceberg results to the effects of an equivalent parameterized iceberg flux.In our model without interactive icebergs, the parameterized fluxes are distributed homogeneously South of 55°S, whereas dynamic icebergs are found to be concentrated closer to shore except for a plume of icebergs floating North–East from the tip of the Antarctic Peninsula. Compared to homogeneous fluxes, the dynamic icebergs lead to a 10% greater net production of Antarctic bottom water (AABW). This increased bottom water production involves open ocean convection, which is enhanced by a less efficient stratification of the ocean when comparing to a homogeneous flux distribution.Icebergs facilitate the formation of sea-ice. In the sensitivity experiments, both the fresh water and the cooling flux lead to a significant increase in sea-ice area of 12% and 6%, respectively, directly affecting the highly coupled and interactive air/sea/ice system. The consequences are most pronounced along the sea-ice edge, where this sea-ice facilitation has the greatest potential to affect ocean stratification, for example by heat insulation and wind shielding, which further amplifies the cooling and freshening of the surface waters. 相似文献
13.
I. I. Mokhov 《Izvestiya Atmospheric and Oceanic Physics》2013,49(1):1-15
The results of Russian climate studies conducted in 2007–2010, which are based on the review prepared for the National Report on Meteorology and Atmospheric Sciences submitted to the 25th General Assembly of the International Union of Geodesy and Geophysics (Melbourne, June 28–July 7, 2011), are presented. The features of climate anomalies in Russian regions are discussed within the scope of general tendencies of global and regional climate changes on the basis of data obtained from observations, reanalysis, and model simulations in comparison with paleoreconstructions. 相似文献
14.
《Ocean Modelling》2007,16(3-4):236-249
Observational studies of the Pacific basin since the 1950s have demonstrated that a decrease (increase) in tropical Pacific sea surface temperatures (SSTs) is significantly correlated with a spin-up (slow-down) of the Pacific Subtropical Cells (STCs). STCs are shallow wind-driven overturning circulations that provide a pathway by which extratropical atmospheric variability can impact the equatorial Pacific thermocline and, through upwelling in the eastern equatorial Pacific, tropical Pacific SSTs. Recent studies have shown that this observed relationship between SSTs and STCs is absent in coupled climate model simulations of the late 19th–20th centuries. In this paper we investigate what causes this relationship to breakdown and to what extent this limits the models’ ability to simulate observed climate change in the equatorial Pacific since the late 19th century. To provide insight into these questions we first show that the NCAR Community Climate System Model’s simulation of observed climate change since the 1970s has a robust signal in the equatorial Pacific that bears a close resemblance to observations. Strikingly, absent is a robust signal in the equatorial thermocline. Our results suggest that the coupled model may be reproducing the observed local ocean response to changes in forcing but inadequately reproducing the remote STC-forcing of the tropical Pacific due to the underestimate of extratropical winds that force these ocean circulations. These conclusions are found to be valid in five different coupled climate model simulations of the late 19th–20th centuries (CCSM3, GISS EH, GFDL CM2.1, CSIRO-Mk3, and HadCM3). 相似文献
15.
It is generally accepted that a climate shift occurred about 1977 that affected the dynamics of North Pacific marine ecosystems. Agreement on the possibility of further climate shifts in 1989 and the late 1990s is yet to be achieved. However, there have been changes in the dynamics of key commercial fishes that indicate changes in their environment occurred in the early 1990s, and possibly around 1998. One method of measuring climate change is to observe the dynamics of species that could be affected.Several studies have described decadal-scale changes in North Pacific climate–ocean conditions. Generally, these studies focus on a single index. Using principal components analysis, we use a composite index based on three aspects of climate ocean conditions: the Aleutian Low Pressure Index, the Pacific Atmospheric Circulation Index and the Pacific Interdecadal Oscillation Index. We link this composite index (Atmospheric Forcing Index) to decadal-scale changes in British Columbia salmon and other fish populations. Around 1989 there was a change from intense Aleutian Lows (above average south-westerly and westerly circulation patterns and warming of coastal sea surface temperatures) to average Aleutian Lows (less frequent south-westerly and westerly circulation and slightly cooler coastal sea surface temperatures in winter). These climate–ocean changes were associated with changes in the abundance and ocean survival of salmon (Oncorhynchus spp.), distribution and spawning behaviour of hake (Merluccius productus) and sardines (Sardinops sagax) and in recruitment patterns of several groundfish species. 相似文献
16.
In this paper, a comparison among the seven large meanders of the Kuroshio is made in order to probe into their similarity and differences. The major results are described as follows.1. Although the three phases for the seven large meanders such as their formations, maturity, as well as decline are very similar to one another, each meander has its own trivial difference in detail.2.The paths of the first six large meanders in the mature phase may be classified into ten types: U1, V1, U2, V2, U1', V1', U2', V2',φ and W.3.The seven large meanders may be grouped into two patterns, i. e. , pattern Ⅰ and pattern Ⅱ. Pattern Ⅰ includes the first and the fourth large meanders, and pattern Ⅱ includes the rest of the above meanders.4. Four standards for identifying the large meanders of the Kuroshio are put forward. 相似文献
17.
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
18.
《Ocean Modelling》2003,5(2):157-170
Model results from a regional model (BRIOS) of the Southern Ocean that includes ice shelf cavities and the interaction between ocean and ice shelves are used to derive a simple parameterization for ice shelf melting and the corresponding fresh water flux in large-scale ocean climate models. The parameterization assumes that the heat loss and fresh water gain due to the ice shelves are proportional to the difference in freezing temperature at the ice shelf edge base and the oceanic temperature on the shelf/slope area of the adjacent ocean as well as an effective area of interaction. This area is proportional to the along-shelf width of ice shelf and an effective cross-shelf distance, which turns out to be rather uniform (5–15 km) for a variety of different ice shelves. The proposed parameterization is easy to implement and valid for a wide range of circumstances. An application of the proposed scheme in a global ice ocean model (CLIO) supports our hypothesis that it can be used successfully and improves both the ocean and sea ice component of the model. This parameterization should also be used in models of the climate system that include a coupling between an ice sheet and an oceanic component. 相似文献
19.
On the basis of the wind-energy method, we estimate the distributions of the parameters of a longshore flux of sediments formed
near the west coast of the Bakal’skaya Spit (in the northwest part of the Crimea) under the conditions of heavy storms whose
action caused a significant erosion of the west coast of the spit and retreat of the coastline in January and November 2007.
The calculations are carried out by using the actual directions and velocities of the winds recorded in the investigated region.
We analyze the trends of changes in the formation of the coastal zone caused by the nonuniform distribution of the intensity
of longshore transportation of sediments. In analyzing the causes of formation of gullies in the barrier of the Bakal’skoe
Lake and in the narrow distal part of the body of the spit, we make an attempt of interpretation of the quantities characterizing
the force of the frontal action of waves. The obtained numerical results are confirmed by the data of field observations. 相似文献
20.
From 1979 to 1989, the current Qingshuigou course of the Huanghe River formed a sub - delta which resembles a beak extending into the Laizhou Bay. It covers 618 km2 in area. To meet the needs of developing and constructing the Huanghe River Delta and under the presupposition of keeping the current course for 15-20 a, we forecast mainly by using the OM (1, 1) model that the front border of the sub-delta will be close to 119°30'E and its area will become 923 km2by the end of the year 2000. The Huanghe River will make land 760 km2 in area. 相似文献