2014 Vol. 36, No. 3
Display Method:
2014, 36(3): .
Abstract:
2014, 36(3): 1-8.
doi: 10.3969/J.ISSN.0253-4193.2014.03.001
Abstract:
Based on the ROMS model, the high resolution tidal model for principal tidal constituents M2, S2, K1 and O1 in the Indonesias Sea (15.52°S~7.13°N,110.39°~134.15°E) is established. The model results are compared with observations at 29 TOPEX/Poseidon (T/P) crossover points, showing satisfactory agreement. The root-mean-square (RMS) deviations in amplitude and phase-lag are respectively 3.4 cm and 5.9° for M2, 1.7 cm and 6.3° for S2, 1.1 cm and 5.8° for K1 and 1.2 cm and 4.4° for O1. The vector RMS deviations for M2, S2, K1 and O1 are 3.8 cm, 2.4 cm, 1.9 cm and 1.3 cm respectively. The relative deviation of numerical results is about 10%. Based on the numerical results, the tidal characteristics and tidal energy flux are analyzed. Except for the Java Sea, the Indonesian seas are mainly irregular semidiurnal tide areas. The diurnal tidal energy propagates mainly from the Pacific Ocean to the Indonesian seas, however the semidiurnal tidal energy propagates from the Indian Ocean to the Indonesian seas.
Based on the ROMS model, the high resolution tidal model for principal tidal constituents M2, S2, K1 and O1 in the Indonesias Sea (15.52°S~7.13°N,110.39°~134.15°E) is established. The model results are compared with observations at 29 TOPEX/Poseidon (T/P) crossover points, showing satisfactory agreement. The root-mean-square (RMS) deviations in amplitude and phase-lag are respectively 3.4 cm and 5.9° for M2, 1.7 cm and 6.3° for S2, 1.1 cm and 5.8° for K1 and 1.2 cm and 4.4° for O1. The vector RMS deviations for M2, S2, K1 and O1 are 3.8 cm, 2.4 cm, 1.9 cm and 1.3 cm respectively. The relative deviation of numerical results is about 10%. Based on the numerical results, the tidal characteristics and tidal energy flux are analyzed. Except for the Java Sea, the Indonesian seas are mainly irregular semidiurnal tide areas. The diurnal tidal energy propagates mainly from the Pacific Ocean to the Indonesian seas, however the semidiurnal tidal energy propagates from the Indian Ocean to the Indonesian seas.
2014, 36(3): 9-18.
doi: 10.3969/J.ISSN.0253-4193.2014.03.002
Abstract:
The expansion of the Changjiang diluted water (CDW) is a dominant hdrographic phenomenon in the East China Sea,which is mainly in the shape of plume. However,there are some low salinity water lenses (LSWL) in partial time of some years. The effects of wind,runoff,Taiwan Warm Current,tide and baroclinic instability on LSWL have been discussed in the previous studies. Tide induced residual current and tidal mixing may both make effect on CDW and LSWL,but there are lack of discussions on the former. In this paper,some numerical simulations are made to analyze the dynamic mechanism of LSWL in August 1983,and more discussions are put on the effects of tide induced residual current and tidal mixing. Tide induced Lagrange current drove part of CDW northward from the river mouth,then turned it eastward in the shape of tongue near 32°N,which was helpful for forming LSWL in the northeast out of the estuary. Tidal vertical mixing strengthened from neap tide to spring tide,the surface salinity at the shallow water increased faster than that at the deep water,which was also helpful for forming LSWL in the northeast out of the estuary.
The expansion of the Changjiang diluted water (CDW) is a dominant hdrographic phenomenon in the East China Sea,which is mainly in the shape of plume. However,there are some low salinity water lenses (LSWL) in partial time of some years. The effects of wind,runoff,Taiwan Warm Current,tide and baroclinic instability on LSWL have been discussed in the previous studies. Tide induced residual current and tidal mixing may both make effect on CDW and LSWL,but there are lack of discussions on the former. In this paper,some numerical simulations are made to analyze the dynamic mechanism of LSWL in August 1983,and more discussions are put on the effects of tide induced residual current and tidal mixing. Tide induced Lagrange current drove part of CDW northward from the river mouth,then turned it eastward in the shape of tongue near 32°N,which was helpful for forming LSWL in the northeast out of the estuary. Tidal vertical mixing strengthened from neap tide to spring tide,the surface salinity at the shallow water increased faster than that at the deep water,which was also helpful for forming LSWL in the northeast out of the estuary.
2014, 36(3): 19-29.
doi: 10.3969/J.ISSN.0253-4193.2014.03.003
Abstract:
To research the current character,seasonal variation and pattern in vertical profile,vertical current speed and direction were observed using ADP,in summer,winter,spring and autumn from 2006 to 2007,in a fixed site of east China Sea southern Zhejiang Province. The results show: (1) The biggest speed was 148.9 cm/s,with the direction 75°,occurred in spring ebb peak in spring during the four observation periods. The biggest average speed in vertical reached 106.2 cm/s,occurred in spring ebb peak in summer. (2) Significant difference presented in vertical speed profile. In the surface (above 28 m),the current was interfered evidently by sea conditions with the biggest and least average speed in autumn and in winter,respectively; between 20m and 28 m layers,the current was strongest in winter and least in spring season; while below 20 m layer,the current was strongest in summer. The average speed in vertical profile was strongest in summer and least in spring,with the speed of 46.5 cm/s and 33.7 cm/s,respectively. (3) The current direction varied from season to season. In summer the direction was north,while in autumn and winter was south on the whole. However,in spring the current was periodic alternating,and the north current was dominated. (4) In vertical profile the current direction was consistent in every layer,while in winter and autumn the current direction varied clearly from bottom to surface. (5) In vertical profile the average residual flow speed was 12.8~29.8 cm/s in the four seasons and the residual flow was strongest in summer and least in spring. The direction of residual flow in summer and spring was northeast in every layer,in winter the direction was southwest. However in autumn the flow direction was complicated relatively,11 m above the seabed was east to north-east-east and below 11m layer the direction was southwest. Conclusion: In the study area,the current was controlled by tide,monsoon and Taiwan warm current together. The monsoon influence to the current in summer and winter was stronger than in spring and autumn,meanwhile the influence became weaker from surface to bottom.
To research the current character,seasonal variation and pattern in vertical profile,vertical current speed and direction were observed using ADP,in summer,winter,spring and autumn from 2006 to 2007,in a fixed site of east China Sea southern Zhejiang Province. The results show: (1) The biggest speed was 148.9 cm/s,with the direction 75°,occurred in spring ebb peak in spring during the four observation periods. The biggest average speed in vertical reached 106.2 cm/s,occurred in spring ebb peak in summer. (2) Significant difference presented in vertical speed profile. In the surface (above 28 m),the current was interfered evidently by sea conditions with the biggest and least average speed in autumn and in winter,respectively; between 20m and 28 m layers,the current was strongest in winter and least in spring season; while below 20 m layer,the current was strongest in summer. The average speed in vertical profile was strongest in summer and least in spring,with the speed of 46.5 cm/s and 33.7 cm/s,respectively. (3) The current direction varied from season to season. In summer the direction was north,while in autumn and winter was south on the whole. However,in spring the current was periodic alternating,and the north current was dominated. (4) In vertical profile the current direction was consistent in every layer,while in winter and autumn the current direction varied clearly from bottom to surface. (5) In vertical profile the average residual flow speed was 12.8~29.8 cm/s in the four seasons and the residual flow was strongest in summer and least in spring. The direction of residual flow in summer and spring was northeast in every layer,in winter the direction was southwest. However in autumn the flow direction was complicated relatively,11 m above the seabed was east to north-east-east and below 11m layer the direction was southwest. Conclusion: In the study area,the current was controlled by tide,monsoon and Taiwan warm current together. The monsoon influence to the current in summer and winter was stronger than in spring and autumn,meanwhile the influence became weaker from surface to bottom.
2014, 36(3): 30-38.
doi: 10.3969/J.ISSN.0253-4193.2014.03.004
Abstract:
The negative storm surge features based on the last 10 a tidal data of 9 coastal tide gauges in Bohai Sea has analyzed in this paper, the results show that: average annual negative storm surge of 50 and 100 cm is more than 30 d and 6d respectively, and September to April next year is the most frequently.A tide-storm surge coupled model with high resolution has been simulated tide, the average RMS is 18.5 cm for the coastal tide gauge, and the tidal characteristic quantities of each point at deepwater channel has been calculated for tide prediction.The large negative storm surge for last 10 a has been simulated base on the coupled model and the calculated results agree well with the observations, indicates that the coupled model can provide a useful reference on the tide forecast for the deepwater channel in Bohai Sea.
The negative storm surge features based on the last 10 a tidal data of 9 coastal tide gauges in Bohai Sea has analyzed in this paper, the results show that: average annual negative storm surge of 50 and 100 cm is more than 30 d and 6d respectively, and September to April next year is the most frequently.A tide-storm surge coupled model with high resolution has been simulated tide, the average RMS is 18.5 cm for the coastal tide gauge, and the tidal characteristic quantities of each point at deepwater channel has been calculated for tide prediction.The large negative storm surge for last 10 a has been simulated base on the coupled model and the calculated results agree well with the observations, indicates that the coupled model can provide a useful reference on the tide forecast for the deepwater channel in Bohai Sea.
2014, 36(3): 39-47.
doi: 10.3969/J.ISSN.0253-4193.2014.03.005
Abstract:
The sea ice concentration data, atmospheric temperature data and surface sensible and latent heat net flux data from HadISST1, ERA_Interim and NCEP respectively are examined to investigate the seasonal and spatial distribution variation of the diminishing Arctic sea ice from 1979 to 2011. Moreover, the seasonal atmospheric temperature change responding to Arctic sea ice loss are discussed by analyzing surface albedo feedback, surface sensible and latent heat net flux.Results show that the strongest surface warming occurs in winter and fall and the largest sea ice reduction takes place in summer and fall. Note that the weakest surface warming occurs in summer. This is principally due to the sea ice melt in summer which absorbs latent heat and the warmer lower atmosphere than ocean surface. With the decreasing sea ice, more heat is transferred from the atmosphere to ocean leading to the ice-melt and upper level sea temperature warming. As a result, the near-surface warming is modest in summer. By contrast, sea ice refreezes in winter and fall and releases latent heat. Meanwhile, less ice cover causes more heat transferred from ocean to atmosphere which warms the low level air. This delayed warming effect plays an important role in the different seasonal air temperature change in Arctic. Besides, the regions of largest warming are co-located with those of greatest sea ice reductions. The southeast Arctic and northern Barents Sea are the key areas of the air-sea interaction in fall and winter, respectively.
The sea ice concentration data, atmospheric temperature data and surface sensible and latent heat net flux data from HadISST1, ERA_Interim and NCEP respectively are examined to investigate the seasonal and spatial distribution variation of the diminishing Arctic sea ice from 1979 to 2011. Moreover, the seasonal atmospheric temperature change responding to Arctic sea ice loss are discussed by analyzing surface albedo feedback, surface sensible and latent heat net flux.Results show that the strongest surface warming occurs in winter and fall and the largest sea ice reduction takes place in summer and fall. Note that the weakest surface warming occurs in summer. This is principally due to the sea ice melt in summer which absorbs latent heat and the warmer lower atmosphere than ocean surface. With the decreasing sea ice, more heat is transferred from the atmosphere to ocean leading to the ice-melt and upper level sea temperature warming. As a result, the near-surface warming is modest in summer. By contrast, sea ice refreezes in winter and fall and releases latent heat. Meanwhile, less ice cover causes more heat transferred from ocean to atmosphere which warms the low level air. This delayed warming effect plays an important role in the different seasonal air temperature change in Arctic. Besides, the regions of largest warming are co-located with those of greatest sea ice reductions. The southeast Arctic and northern Barents Sea are the key areas of the air-sea interaction in fall and winter, respectively.
2014, 36(3): 48-60.
doi: 10.3969/J.ISSN.0253-4193.2014.03.006
Abstract:
Contributions of natural and anthropogenic forcings to the twentieth-century Pacific sea surface temperature (SST) decadal variability are evaluated with a climate system model named FGOALS_gl developed by LASG/IAP. The observational data shows that there are three typical periods of the twentieth-century Pacific SST variability: a warming tendency in the early twentieth-century,the weak cooling during 1940s—1970s and the strong warming trend after the 1970s. The first leading mode of the twentieth-century Pacific SST variability features an oscillatorily warming in the whole Pacific basin,and the second one appears as Pacific Decadal Oscillation (PDO) with a significant inter-decadal transition in the late-1970s. The simulations support that the early stage warming is resulted from a combination of the anthropogenic forcing and the internal variability. And the pronounced late twentieth-century warming is dominated by the increase of greenhouse gases(GHGs) forcing. During the two warming periods of the twentieth-century,the natural forcing and internal variability dominate the changes in Kuroshio Extension (KE) region,and the anthropogenic forcing dominates the changes in other parts of Pacific. The first two leading modes of the twentieth-century Pacific SST variability can be reproduced by the all-forcing run. The PDO would become the dominant mode and the inter-decadal transition would take place in the mid-1960s if the anthropogenic forcing is not included. These results indicate that the anthropogenic forcing dominates the warming in the whole Pacific basin and leads to a 10 a delay of the inter-decadal transition. Therefore,the inter-decadal transition of PDO phase is caused by natural forcing,while the anthropogenic forcing can modulate the transition point.
Contributions of natural and anthropogenic forcings to the twentieth-century Pacific sea surface temperature (SST) decadal variability are evaluated with a climate system model named FGOALS_gl developed by LASG/IAP. The observational data shows that there are three typical periods of the twentieth-century Pacific SST variability: a warming tendency in the early twentieth-century,the weak cooling during 1940s—1970s and the strong warming trend after the 1970s. The first leading mode of the twentieth-century Pacific SST variability features an oscillatorily warming in the whole Pacific basin,and the second one appears as Pacific Decadal Oscillation (PDO) with a significant inter-decadal transition in the late-1970s. The simulations support that the early stage warming is resulted from a combination of the anthropogenic forcing and the internal variability. And the pronounced late twentieth-century warming is dominated by the increase of greenhouse gases(GHGs) forcing. During the two warming periods of the twentieth-century,the natural forcing and internal variability dominate the changes in Kuroshio Extension (KE) region,and the anthropogenic forcing dominates the changes in other parts of Pacific. The first two leading modes of the twentieth-century Pacific SST variability can be reproduced by the all-forcing run. The PDO would become the dominant mode and the inter-decadal transition would take place in the mid-1960s if the anthropogenic forcing is not included. These results indicate that the anthropogenic forcing dominates the warming in the whole Pacific basin and leads to a 10 a delay of the inter-decadal transition. Therefore,the inter-decadal transition of PDO phase is caused by natural forcing,while the anthropogenic forcing can modulate the transition point.
2014, 36(3): 61-72.
doi: 10.3969/J.ISSN.0253-4193.2014.03.007
Abstract:
The fidelity of atmospheric circulation over tropical regions, especially subtropical high, monsoon trough and vertical wind shear over the regions of tropical cyclone activity in the coupled general circulation models (CGCM) participating in the Forth Assessment Report (AR4) of Intergovernmental Panel on Climate Change (IPCC)is accessed by virtue of comparing simulated climate field with that of National Center Environmental Prediction(NCEP)/National Center Atmospheric Research(NCAR) during 1948—1999 from July to September. It is found that vast majority of 23 IPCC-AR4 models show a good performance in mean state in 500 hPa height field over the domain 0°—40°N, 0°E—180°—0°W and 850 hPa wind field over the region 20°S—40°N, 0°E—180°—0°W—180°—0°W, but in comparison to that of NCEP/NCAR, most of models show a low bias in 500 hPa height and a strong bias in 850 hPa wind flow.The subtropical high ridge over the western North Pacific of all models is in NE-SW orientation which is similar to that of NCEP/NCAR, but some of models' ridge locates to far away from the latter. Monsoon troughs of four models are absent from 850 hPa flow and six of monsoon troughs in models occur to the west of 140°E. According to the performance of simulation in spatial structure of atmospheric circulation over tropical area, subtropical high ridge, monsoon trough in the western North Pacific and vertical wind shear in active regions of tropical cyclone over western North Pacific in summer(from July to September), the first ten excellent models are successively mpi_echam5、cccma_t63、gfdl_cm2_1、cnrm_cm3、cccma_t47、ukmo_hadgem1、ingv_echam4、ncar_ccsm3_0、csiro_mk3_5、mri_cgcm2_3_2a and the last six models are successively inmcm3_0、iap_fgoals1_0_g、ipsl_cm4、miroc3_2_medres、giss_eh、giss_er.
The fidelity of atmospheric circulation over tropical regions, especially subtropical high, monsoon trough and vertical wind shear over the regions of tropical cyclone activity in the coupled general circulation models (CGCM) participating in the Forth Assessment Report (AR4) of Intergovernmental Panel on Climate Change (IPCC)is accessed by virtue of comparing simulated climate field with that of National Center Environmental Prediction(NCEP)/National Center Atmospheric Research(NCAR) during 1948—1999 from July to September. It is found that vast majority of 23 IPCC-AR4 models show a good performance in mean state in 500 hPa height field over the domain 0°—40°N, 0°E—180°—0°W and 850 hPa wind field over the region 20°S—40°N, 0°E—180°—0°W—180°—0°W, but in comparison to that of NCEP/NCAR, most of models show a low bias in 500 hPa height and a strong bias in 850 hPa wind flow.The subtropical high ridge over the western North Pacific of all models is in NE-SW orientation which is similar to that of NCEP/NCAR, but some of models' ridge locates to far away from the latter. Monsoon troughs of four models are absent from 850 hPa flow and six of monsoon troughs in models occur to the west of 140°E. According to the performance of simulation in spatial structure of atmospheric circulation over tropical area, subtropical high ridge, monsoon trough in the western North Pacific and vertical wind shear in active regions of tropical cyclone over western North Pacific in summer(from July to September), the first ten excellent models are successively mpi_echam5、cccma_t63、gfdl_cm2_1、cnrm_cm3、cccma_t47、ukmo_hadgem1、ingv_echam4、ncar_ccsm3_0、csiro_mk3_5、mri_cgcm2_3_2a and the last six models are successively inmcm3_0、iap_fgoals1_0_g、ipsl_cm4、miroc3_2_medres、giss_eh、giss_er.
2014, 36(3): 73-82.
doi: 10.3969/J.ISSN.0253-4193.2014.03.008
Abstract:
Four vertical mixing parameterization schemes,including M-Y2.0,M-Y2.5 based on wall layer proximity,M-Y2.5 based on surface wave breaking and KPP are applied to simulate the upper structure of temperature in the Yellow Sea in summer,using Princeton Ocean Model with generalized coordinate system(POMgcs) and MIT General Circulation Model(MITgcm). It shows that the depth of the upper mixed layer simulated by M-Y2.0 and M-Y2.5 based on wall layer proximity are both too shallow comparing with the observation. The two schemes mentioned above can hardly well simulate the summer structure of temperature in the Yellow Sea,while both the schemes of the M-Y2.5 based on surface wave breaking and KPP have favorable capability to reconstruct the summer upper mixing layer of temperature in the Yellow Sea. So we suggest that surface wave-induced mixing and flow shear modulate jointly the upper layer structure in the Yellow sea. The upper layer structure of temperature is able to be well simulated through utilizing the rational schemes of vertical mixing parameterization that can embody the effect of the physics processes mentioned above.
Four vertical mixing parameterization schemes,including M-Y2.0,M-Y2.5 based on wall layer proximity,M-Y2.5 based on surface wave breaking and KPP are applied to simulate the upper structure of temperature in the Yellow Sea in summer,using Princeton Ocean Model with generalized coordinate system(POMgcs) and MIT General Circulation Model(MITgcm). It shows that the depth of the upper mixed layer simulated by M-Y2.0 and M-Y2.5 based on wall layer proximity are both too shallow comparing with the observation. The two schemes mentioned above can hardly well simulate the summer structure of temperature in the Yellow Sea,while both the schemes of the M-Y2.5 based on surface wave breaking and KPP have favorable capability to reconstruct the summer upper mixing layer of temperature in the Yellow Sea. So we suggest that surface wave-induced mixing and flow shear modulate jointly the upper layer structure in the Yellow sea. The upper layer structure of temperature is able to be well simulated through utilizing the rational schemes of vertical mixing parameterization that can embody the effect of the physics processes mentioned above.
2014, 36(3): 83-93.
doi: 10.3969/J.ISSN.0253-4193.2014.03.009
Abstract:
The characteristics of temporal and spatial distribution of storm surge in Guangdong Province are studied by historical storm surge. The result indicate that most of storm surge occurred in July and September. The frequency and intensity of storm surge in Leizhou Island are higher than other places in Guangdong Province. The main storm surge disaster occurred from July to October,the districts effected seriously by storm surge are Yangjiang and Leizhou Island. In addition,a study on storm surge hazard research of Yangjiang has been carried out,the result show storm surge effected by a typhoon with central pressure of 970 hPa and 940 hPa is 185 cm and 310 cm respectively.
The characteristics of temporal and spatial distribution of storm surge in Guangdong Province are studied by historical storm surge. The result indicate that most of storm surge occurred in July and September. The frequency and intensity of storm surge in Leizhou Island are higher than other places in Guangdong Province. The main storm surge disaster occurred from July to October,the districts effected seriously by storm surge are Yangjiang and Leizhou Island. In addition,a study on storm surge hazard research of Yangjiang has been carried out,the result show storm surge effected by a typhoon with central pressure of 970 hPa and 940 hPa is 185 cm and 310 cm respectively.
2014, 36(3): 94-103.
doi: 10.3969/J.ISSN.0253-4193.2014.03.010
Abstract:
Spatio-temporal variations of the sea temperature anomaly in the South China Sea (SCS) were investigated based on the reanalysis dataset of China seas from 1986 to 2003. With focus on the evolution of the sea surface temperature anomaly(SSTA) before and after (during April to Jun) the onset of the SCS summer monsoon (SCSSM), its relation with the occasion of the SCSSM onsets was discussed. The results show that, there exists a significant evolution mode on seasonal scale, in which the positive SSTA develops firstly near the sea area west of Palawan in April, and extends rapidly westward and northward in May when the positive SSTA controls the most part of the SCS, and then the SSTA in the SCS achieves a negative-positive phase transition in June. The analysis indicates that, the interannual difference of the SSTA evolution mode was associated significantly with the earlier or later onset of the SCSSM. Synthesizing with the previous studies, it is considered that the anomalous thermal evolution (including trends,speed,magnitude) on intra-seasonal scale in the sea surface of the SCS could be one of important factors to impact earlier and later onset of the SCSSM. According to this, the author established a temperature difference index based on the SSTA evolution in the SCS, which reflects well to the earlier and later onset of the SCSSM. In addition, the evolution of the SSTA can be related closely with the variation of the SCS warm pool (SCSWP). It is found that the SST difference (April-May) anomaly of the SCSWP during the period before the onset of the SCSSM was striking of positive correlation with that of the Indian Ocean warm pool (IOWP), while evident negative relation with that of the Western Pacific warm pool (WPWP). Under the background of formation of the surface thermal pattern and contrast in Indio-Pacific warm pool regions, the anomalous intra-seasonal evolution of the SSTA in the SCS is expected to give rise to the interannual difference of the SCSSM onset (earlier or later) through the thermal effect on the large scale of meridional and zonal atmospheric current anomalies.
Spatio-temporal variations of the sea temperature anomaly in the South China Sea (SCS) were investigated based on the reanalysis dataset of China seas from 1986 to 2003. With focus on the evolution of the sea surface temperature anomaly(SSTA) before and after (during April to Jun) the onset of the SCS summer monsoon (SCSSM), its relation with the occasion of the SCSSM onsets was discussed. The results show that, there exists a significant evolution mode on seasonal scale, in which the positive SSTA develops firstly near the sea area west of Palawan in April, and extends rapidly westward and northward in May when the positive SSTA controls the most part of the SCS, and then the SSTA in the SCS achieves a negative-positive phase transition in June. The analysis indicates that, the interannual difference of the SSTA evolution mode was associated significantly with the earlier or later onset of the SCSSM. Synthesizing with the previous studies, it is considered that the anomalous thermal evolution (including trends,speed,magnitude) on intra-seasonal scale in the sea surface of the SCS could be one of important factors to impact earlier and later onset of the SCSSM. According to this, the author established a temperature difference index based on the SSTA evolution in the SCS, which reflects well to the earlier and later onset of the SCSSM. In addition, the evolution of the SSTA can be related closely with the variation of the SCS warm pool (SCSWP). It is found that the SST difference (April-May) anomaly of the SCSWP during the period before the onset of the SCSSM was striking of positive correlation with that of the Indian Ocean warm pool (IOWP), while evident negative relation with that of the Western Pacific warm pool (WPWP). Under the background of formation of the surface thermal pattern and contrast in Indio-Pacific warm pool regions, the anomalous intra-seasonal evolution of the SSTA in the SCS is expected to give rise to the interannual difference of the SCSSM onset (earlier or later) through the thermal effect on the large scale of meridional and zonal atmospheric current anomalies.
2014, 36(3): 104-112.
doi: 10.3969/J.ISSN.0253-4193.2014.03.011
Abstract:
By hiring CSD(climatological statistical diagnosis), the impacts of ENSO(El Nio-Southern Oscillation) Modoki on the middle and high latitude climate in the Southern Hemisphere and sea-ice anomalies of the South Pole are discussed. Active year and active months of ENSO Modoki are defined by combination of the former research and Modoki's seasonal variation. the CSD methods like correlation analysis, partial correlation analysis, composite analysis, lead-lag correlation analysis and so on are then imported to analyze meteorological elements field and ice data between January 1979 and December 2010. Through deep analysis and discussion, the teleconnection pattern and corresponding dynamic mechanism of ENSO Modoki are revealed. The result shows that there is an important relationship between ENSO Modoki and middle-high latitude climate and sea-ice anomalies in the Southern Hemisphere, the Ferrel Circulation is the most possible way of occurrence of teleconnection.
By hiring CSD(climatological statistical diagnosis), the impacts of ENSO(El Nio-Southern Oscillation) Modoki on the middle and high latitude climate in the Southern Hemisphere and sea-ice anomalies of the South Pole are discussed. Active year and active months of ENSO Modoki are defined by combination of the former research and Modoki's seasonal variation. the CSD methods like correlation analysis, partial correlation analysis, composite analysis, lead-lag correlation analysis and so on are then imported to analyze meteorological elements field and ice data between January 1979 and December 2010. Through deep analysis and discussion, the teleconnection pattern and corresponding dynamic mechanism of ENSO Modoki are revealed. The result shows that there is an important relationship between ENSO Modoki and middle-high latitude climate and sea-ice anomalies in the Southern Hemisphere, the Ferrel Circulation is the most possible way of occurrence of teleconnection.
2014, 36(3): 113-120.
doi: 10.3969/J.ISSN.0253-4193.2014.03.012
Abstract:
The trajectory numerical forecasting of oil spill is very important to the accident handling of oil spill. Many researchers did a lot of work on oil spill forecasting technology. However, the success of each model depends on the model structure and schemes, the accuracy of input data (such as wind, current, oil source information) and the interpretation of results. Input data, especially wind data and current data, are subjected to many error sources. Now, the accuration of oil spill numerical forecasting still can't reach the level we need. With the developing of observation technology and capability, it becomes a major question that how to use these real-time observation data to improve the accuration of oil spill numerical forecasting in order to meet the requirements of emergency forecast. The oil spill operational numerical forecasting system of the Bohai Sea was established on 2008 by National Marine Environmental Forecasting Center(NMEFC). In the paper, in order to resolve these real troubles in the oil spill operational numerical forecasting system of the Bohai Sea, the OI assimilation technology is applied in the oil spill emergency forecasting system of the Bohai Sea by using the observation data of wind field of five oil platforms from January 2010 to February 2011 in the Bohai Sea. The relevant scale factor, which is a very important factor in OI assimilation method, is determined by cross-correct method. Then the optimal value of parameter in OI assimilation technology is determined in the case of the five observation stations such this distribution. After that, the technology is applied in an ideal case and a real case, the results both approve that the applying of the OI assimilation technology improve the accuration of oil spill numerical forecasting results. This work provide a simple method to improve the accuration of oil spill numerical forecasting results, and it also meet the requirements of the oil spill emergency prediction in term of convenience and quickness.
The trajectory numerical forecasting of oil spill is very important to the accident handling of oil spill. Many researchers did a lot of work on oil spill forecasting technology. However, the success of each model depends on the model structure and schemes, the accuracy of input data (such as wind, current, oil source information) and the interpretation of results. Input data, especially wind data and current data, are subjected to many error sources. Now, the accuration of oil spill numerical forecasting still can't reach the level we need. With the developing of observation technology and capability, it becomes a major question that how to use these real-time observation data to improve the accuration of oil spill numerical forecasting in order to meet the requirements of emergency forecast. The oil spill operational numerical forecasting system of the Bohai Sea was established on 2008 by National Marine Environmental Forecasting Center(NMEFC). In the paper, in order to resolve these real troubles in the oil spill operational numerical forecasting system of the Bohai Sea, the OI assimilation technology is applied in the oil spill emergency forecasting system of the Bohai Sea by using the observation data of wind field of five oil platforms from January 2010 to February 2011 in the Bohai Sea. The relevant scale factor, which is a very important factor in OI assimilation method, is determined by cross-correct method. Then the optimal value of parameter in OI assimilation technology is determined in the case of the five observation stations such this distribution. After that, the technology is applied in an ideal case and a real case, the results both approve that the applying of the OI assimilation technology improve the accuration of oil spill numerical forecasting results. This work provide a simple method to improve the accuration of oil spill numerical forecasting results, and it also meet the requirements of the oil spill emergency prediction in term of convenience and quickness.
2014, 36(3): 121-126.
doi: 10.3969/J.ISSN.0253-4193.2014.03.013
Abstract:
The first oceanic dynamic environment satellite—HY-2A was launched in August 16, 2011. Significant Wave Height (SWH) is one of the important parameters which can be monitored by HY-2A satellite altimeter. The SWH operational inversion algorithm of HY-2A altimeter is detail introduced in the paper, and the algorithm obtained SWH by least-square method. The SWH of HY-2A altimeter computered by the operational processing is compared to the results of Jason-2 and NDBC buoys. The result showed that the standard deviation is -0.26 cm and RMS is 0.58 cm between HY-2A and Jason-2, and the standard deviation is -0.22 cm and RMS is 0.37 m between HY-2A and NDBC buoys. The results demonstrated that the SWH inversion algorithm used in the operational processing system of HY-2A altimeter is feasible.
The first oceanic dynamic environment satellite—HY-2A was launched in August 16, 2011. Significant Wave Height (SWH) is one of the important parameters which can be monitored by HY-2A satellite altimeter. The SWH operational inversion algorithm of HY-2A altimeter is detail introduced in the paper, and the algorithm obtained SWH by least-square method. The SWH of HY-2A altimeter computered by the operational processing is compared to the results of Jason-2 and NDBC buoys. The result showed that the standard deviation is -0.26 cm and RMS is 0.58 cm between HY-2A and Jason-2, and the standard deviation is -0.22 cm and RMS is 0.37 m between HY-2A and NDBC buoys. The results demonstrated that the SWH inversion algorithm used in the operational processing system of HY-2A altimeter is feasible.
2014, 36(3): 127-133.
doi: 10.3969/J.ISSN.0253-4193.2014.03.014
Abstract:
Shear wave in-situ testing is one of the techniques that are commonly useful and effective. The test results can be used for the analysis of soil dynamics. The testing conditions of marine stratum are bad, and in some cases for shear wave velocity prediction is particularly important. In order to study on precise prediction method of shear wave velocity of marine stratum, according to the Jiangsu offshore and intertidal shear wave velocity testing results, the shear wave velocity prediction methods are summarized and evaluated. The statistical relationships between shear wave velocity characteristics and physical-mechanical index of soil are analyzed. Based on the generalized regression neural network (GRNN) method, according to the statistical relationship, the nonlinear mapping relationship between physical-mechanical indexes of the soil and shear wave velocity tested is established. The prediction of shear wave velocity is analyzed and studied. It shows that the good prediction results can be obtained through the method.
Shear wave in-situ testing is one of the techniques that are commonly useful and effective. The test results can be used for the analysis of soil dynamics. The testing conditions of marine stratum are bad, and in some cases for shear wave velocity prediction is particularly important. In order to study on precise prediction method of shear wave velocity of marine stratum, according to the Jiangsu offshore and intertidal shear wave velocity testing results, the shear wave velocity prediction methods are summarized and evaluated. The statistical relationships between shear wave velocity characteristics and physical-mechanical index of soil are analyzed. Based on the generalized regression neural network (GRNN) method, according to the statistical relationship, the nonlinear mapping relationship between physical-mechanical indexes of the soil and shear wave velocity tested is established. The prediction of shear wave velocity is analyzed and studied. It shows that the good prediction results can be obtained through the method.
2014, 36(3): 134-142.
doi: 10.3969/J.ISSN.0253-4193.2014.03.015
Abstract:
In this paper,to better simulate the actual heterogeneity of the seabed sediment,the random medium theory is introduced into the two-phase medium theory. Firstly,through the high-order staggered-mesh finite different simulation of random two-phase media,simulated the propagation of the seismic wave of three different the sediments,which are shaly sand,mudstones,muddy conglomerate. Then,the wavelet transformation technology is used to obtain the envelopes of reflection,called as the feature vector,which will be used as the input term of neural network. Finally,support vector machine neural network based on particle swarm optimization was applied to classify these data. To further investigate the anti-noise ability of the proposed method,the 10%,30% and 50% of Gaussian white noise was added into the original data and the optimized support vector machines still achieved good classification prediction. Based on the repeatable,convenient of the computer simulation and the relevant high accuracy and the robustness of SVM,a total solution of a classification,which will be easier,deeper,further to sturdy the feature of reflection of sediments is proposed in the article.
In this paper,to better simulate the actual heterogeneity of the seabed sediment,the random medium theory is introduced into the two-phase medium theory. Firstly,through the high-order staggered-mesh finite different simulation of random two-phase media,simulated the propagation of the seismic wave of three different the sediments,which are shaly sand,mudstones,muddy conglomerate. Then,the wavelet transformation technology is used to obtain the envelopes of reflection,called as the feature vector,which will be used as the input term of neural network. Finally,support vector machine neural network based on particle swarm optimization was applied to classify these data. To further investigate the anti-noise ability of the proposed method,the 10%,30% and 50% of Gaussian white noise was added into the original data and the optimized support vector machines still achieved good classification prediction. Based on the repeatable,convenient of the computer simulation and the relevant high accuracy and the robustness of SVM,a total solution of a classification,which will be easier,deeper,further to sturdy the feature of reflection of sediments is proposed in the article.
Email alert
RSS