2014 Vol. 33, No. 1
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2014, 33(1): .
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2014, 33(1): .
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Acta Oceanologica Sinica (AOS) is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.
Acta Oceanologica Sinica (AOS) is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.
2014, 33(1): 1-10.
doi: 10.1007/s13131-014-0419-4
Abstract:
Dissolved organic carbon (DOC) and particulate organic carbon (POC) are basic variables for the ocean carbon cycle. Knowledge of the distribution and inventory of these variables is important for a better estimation and understanding of the global carbon cycle. Owing to its considerable advantages in spatial and temporal coverage, remote sensing data provide estimates of DOC and POC inventories,which are able to give a synthetic view for the distribution and transportation of carbon pools. To estimate organic carbon inventories using remote sensing involves integration of the surface concentration and vertical profile models, and the development of these models is critical to the accuracy of estimates. Hence, the distribution and control factors of DOC and POC in the ocean first are briefly summarized, and then studies of DOC and POC inventories and flux estimations are reviewed, most of which are based on field data and few of which consider the vertical distributions of POC or DOC. There is some research on the estimation of POC inventory by remote sensing,mainly in the open ocean, in which three kinds of vertical profilemodels have been proposed: the uniform, exponential decay, and Gauss models. However, research on remote-sensing estimation of the DOC inventory remains lacking. A synthetic reviewof approaches used to estimate the organic carbon inventories is offered and the future development of methods is discussed for such estimates using remote sensing data in coastal waters.
Dissolved organic carbon (DOC) and particulate organic carbon (POC) are basic variables for the ocean carbon cycle. Knowledge of the distribution and inventory of these variables is important for a better estimation and understanding of the global carbon cycle. Owing to its considerable advantages in spatial and temporal coverage, remote sensing data provide estimates of DOC and POC inventories,which are able to give a synthetic view for the distribution and transportation of carbon pools. To estimate organic carbon inventories using remote sensing involves integration of the surface concentration and vertical profile models, and the development of these models is critical to the accuracy of estimates. Hence, the distribution and control factors of DOC and POC in the ocean first are briefly summarized, and then studies of DOC and POC inventories and flux estimations are reviewed, most of which are based on field data and few of which consider the vertical distributions of POC or DOC. There is some research on the estimation of POC inventory by remote sensing,mainly in the open ocean, in which three kinds of vertical profilemodels have been proposed: the uniform, exponential decay, and Gauss models. However, research on remote-sensing estimation of the DOC inventory remains lacking. A synthetic reviewof approaches used to estimate the organic carbon inventories is offered and the future development of methods is discussed for such estimates using remote sensing data in coastal waters.
2014, 33(1): 11-23.
doi: 10.1007/s13131-014-0429-2
Abstract:
A global prognostic model based on MOM4p1, which is a primitive equation non Boussinesq numerical model, has been integrated with 1 400 years from the state of rest based on the realistic topography to study the long-term pattern of combined wind-driven and thermodynamically-driven general circulation. The model is driven by monthly climatological mean forces and includes 192×189 horizontal grids and 31 pressure-based vertical levels. The main objective is to investigate themass and heat transports at interbasin passages and their compensations and roles in the global ocean circulation under equilibriumstate of long-termspin up. The kinetic energy analysis divides the spin up process into three stages: the quasi-stable state ofwind driven current, the growing phase of thermodynamical circulation and the equilibriumstate of thermohaline circulation. It is essential to spin up over a thousand years in order to reach the thermohaline equilibrium state from a state of rest. The Arctic Through flow from the Bering Strait to the Greenland Sea and the Indonesian Through flow (ITF) are captured and examined with their compensations and existing data. Analysis reveals that the slope structures of sea surface height are the dynamical driving mechanism of the Pacific-Arctic-Atlantic through flow and ITF. The analysis denotes, in spite of O (1.4×106 m3/s) of the southward volume transport in the northern Atlantic, that there is stillO (1 PW) of heat transported northward since the northward currents in the upper layer carrymuch higher temperature water than the southward flowing northern Atlantic deep water (NADW).Meridional volume and heat transports are focused on the contributions to NAD Wrenewals and Atlantic meridional overturning circulation (AMOC). Quantitative descriptions of the interbasin exchanges are explained bymeridional compensations and supported by previous observations and numericalmodeling results. Analysis indicates that the volume and heat exchanges on the interbasin passages proposed in this article manifest their hub roles in the Great Ocean Conveyor System.
A global prognostic model based on MOM4p1, which is a primitive equation non Boussinesq numerical model, has been integrated with 1 400 years from the state of rest based on the realistic topography to study the long-term pattern of combined wind-driven and thermodynamically-driven general circulation. The model is driven by monthly climatological mean forces and includes 192×189 horizontal grids and 31 pressure-based vertical levels. The main objective is to investigate themass and heat transports at interbasin passages and their compensations and roles in the global ocean circulation under equilibriumstate of long-termspin up. The kinetic energy analysis divides the spin up process into three stages: the quasi-stable state ofwind driven current, the growing phase of thermodynamical circulation and the equilibriumstate of thermohaline circulation. It is essential to spin up over a thousand years in order to reach the thermohaline equilibrium state from a state of rest. The Arctic Through flow from the Bering Strait to the Greenland Sea and the Indonesian Through flow (ITF) are captured and examined with their compensations and existing data. Analysis reveals that the slope structures of sea surface height are the dynamical driving mechanism of the Pacific-Arctic-Atlantic through flow and ITF. The analysis denotes, in spite of O (1.4×106 m3/s) of the southward volume transport in the northern Atlantic, that there is stillO (1 PW) of heat transported northward since the northward currents in the upper layer carrymuch higher temperature water than the southward flowing northern Atlantic deep water (NADW).Meridional volume and heat transports are focused on the contributions to NAD Wrenewals and Atlantic meridional overturning circulation (AMOC). Quantitative descriptions of the interbasin exchanges are explained bymeridional compensations and supported by previous observations and numericalmodeling results. Analysis indicates that the volume and heat exchanges on the interbasin passages proposed in this article manifest their hub roles in the Great Ocean Conveyor System.
2014, 33(1): 24-34.
doi: 10.1007/s13131-014-0424-7
Abstract:
A two-dimensional numerical model, which is configured on the basis of Princeton ocean model (POM), is used to study the effect of Stokes production (SP) of the turbulent kinetic energy on a density profile and Ekman transport in an idealized shelf region in summer. The energy input from SP is parameterized and included into the Mellor-Yamada turbulence closure sub model. Results reveal that the intensity of wind-driven upwelling fronts near the sea surface isweakened by the SP-associated turbulent kinetic energy input. The vertical eddy viscosity coefficient in the surface boundary layer is enhanced greatly owing to the impact of SP,which decreases the alongshore velocity and changes the distributionof upwelling. In addition, the SP-induced mixing easily suppresses the strong stratification and significantly increases the depth of the uppermixed layer (ML) under strong winds.
A two-dimensional numerical model, which is configured on the basis of Princeton ocean model (POM), is used to study the effect of Stokes production (SP) of the turbulent kinetic energy on a density profile and Ekman transport in an idealized shelf region in summer. The energy input from SP is parameterized and included into the Mellor-Yamada turbulence closure sub model. Results reveal that the intensity of wind-driven upwelling fronts near the sea surface isweakened by the SP-associated turbulent kinetic energy input. The vertical eddy viscosity coefficient in the surface boundary layer is enhanced greatly owing to the impact of SP,which decreases the alongshore velocity and changes the distributionof upwelling. In addition, the SP-induced mixing easily suppresses the strong stratification and significantly increases the depth of the uppermixed layer (ML) under strong winds.
2014, 33(1): 35-41.
doi: 10.1007/s13131-014-0430-9
Abstract:
A storm surge is an abnormal sharp rise or fall in the seawater level produced by the strong wind and low pressure field of an approaching storm system. A storm tide is a water level rise or fall caused by the combined effect of the stormsurge and an astronomical tide. The stormsurge depends onmany factors, such as the tracks of typhoon movement, the intensity of typhoon, the topography of sea area, the amplitude of tidal wave, the period during which the storm surge couples with the tidal wave. When coupling with different parts of a tidal wave, the storm surges caused by a typhoon vary widely. The variation of the storm surges is studied. An once-in-a-century storm surge was caused by Typhoon 7203 at Huludao Port in the north of the Liaodong Bay from July 26th to 27th, 1972. The maximum storm surge is about 1.90 m. The wind field and pressure field used in numerical simulations in the research were derived from the historical data of the Typhoon 7203 from July 23rd to 28th, 1972. DHI Mike 21 is used as the software tools. The whole Bohai Sea is defined as the computational domain. The numerical simulation models are forced with sea levels at water boundaries, that is the tide along the Bohai Straits from July 18th to 29th (2012). The tide wave and the stormtides caused by the wind field and pressure field mentioned above are calculated in the numerical simulations. The coupling processes of storm surges and tidal waves are simulated in the following way. The first simulation start date and time are 00:00 July 18th, 2012; the second simulation start date and time are 03:00 July 18th, 2012. There is a three-hour lag between the start date and time of the simulation and that of the former one, the last simulation start date and time are 00:00 July 25th, 2012. All the simulations have a same duration of 5 days, which is same as the time length of typhoon data. With the first day and the second day simulation output, which is affected by the initial field, being ignored, only the 3rd to 5th day simulation results are used to study the rules of the storm surges in the north of the Liaodong Bay. In total, 57 cases are calculated and analyzed, including the coupling effects between the storm surge and a tidal wave during different tidal durations and on different tidal levels. Based on the results of the 57 numerical examples, the following conclusions are obtained: For the same location, the maximum storm surges are determined by the primary vibration (the storm tide keeps rising quickly) duration and tidal duration. If the primary vibration duration is a part of the flood tidal duration, the maximum storm surge is lower (1.01, 1.05 and 1.37mat the Huludao Port, the Daling Estuary and the Liaohe Estuary respectively). If the primary vibration duration is a part of the ebb tidal duration, the maximum storm surge is higher (1.92, 2.05 and 2.80 m at the Huludao Port, the Daling Estuary and the Liaohe Estuary respectively). In the mean time, the sea level restrains the growth of storm surges. The hour of the highest storm tide has a margin of error of plus orminus 80min, comparing the high water hour of the astronomical tide, in the north of the Liaodong Bay.
A storm surge is an abnormal sharp rise or fall in the seawater level produced by the strong wind and low pressure field of an approaching storm system. A storm tide is a water level rise or fall caused by the combined effect of the stormsurge and an astronomical tide. The stormsurge depends onmany factors, such as the tracks of typhoon movement, the intensity of typhoon, the topography of sea area, the amplitude of tidal wave, the period during which the storm surge couples with the tidal wave. When coupling with different parts of a tidal wave, the storm surges caused by a typhoon vary widely. The variation of the storm surges is studied. An once-in-a-century storm surge was caused by Typhoon 7203 at Huludao Port in the north of the Liaodong Bay from July 26th to 27th, 1972. The maximum storm surge is about 1.90 m. The wind field and pressure field used in numerical simulations in the research were derived from the historical data of the Typhoon 7203 from July 23rd to 28th, 1972. DHI Mike 21 is used as the software tools. The whole Bohai Sea is defined as the computational domain. The numerical simulation models are forced with sea levels at water boundaries, that is the tide along the Bohai Straits from July 18th to 29th (2012). The tide wave and the stormtides caused by the wind field and pressure field mentioned above are calculated in the numerical simulations. The coupling processes of storm surges and tidal waves are simulated in the following way. The first simulation start date and time are 00:00 July 18th, 2012; the second simulation start date and time are 03:00 July 18th, 2012. There is a three-hour lag between the start date and time of the simulation and that of the former one, the last simulation start date and time are 00:00 July 25th, 2012. All the simulations have a same duration of 5 days, which is same as the time length of typhoon data. With the first day and the second day simulation output, which is affected by the initial field, being ignored, only the 3rd to 5th day simulation results are used to study the rules of the storm surges in the north of the Liaodong Bay. In total, 57 cases are calculated and analyzed, including the coupling effects between the storm surge and a tidal wave during different tidal durations and on different tidal levels. Based on the results of the 57 numerical examples, the following conclusions are obtained: For the same location, the maximum storm surges are determined by the primary vibration (the storm tide keeps rising quickly) duration and tidal duration. If the primary vibration duration is a part of the flood tidal duration, the maximum storm surge is lower (1.01, 1.05 and 1.37mat the Huludao Port, the Daling Estuary and the Liaohe Estuary respectively). If the primary vibration duration is a part of the ebb tidal duration, the maximum storm surge is higher (1.92, 2.05 and 2.80 m at the Huludao Port, the Daling Estuary and the Liaohe Estuary respectively). In the mean time, the sea level restrains the growth of storm surges. The hour of the highest storm tide has a margin of error of plus orminus 80min, comparing the high water hour of the astronomical tide, in the north of the Liaodong Bay.
2014, 33(1): 42-47.
doi: 10.1007/s13131-014-0421-x
Abstract:
The Argo data are used to calculate eddy (turbulence) heat transport (EHT) in the global ocean and analyze its horizontal distribution and vertical structure. We calculate the EHT by averaging all the v',T' profiles within each 2°× 2° bin. The velocity and temperature anomalies are obtained by removing their climatological values from the Argo "instantaneous" values respectively. Through the Student's t-test and an error evaluation, we obtained a total of 87% Argo bins with significant depth-integrated EHTs (D-EHTs). The results reveal a positive-and-negative alternating D-EHT pattern along the western boundary currents (WBC) and Antarctic Circumpolar Current (ACC). The zonally-integrated D-EHT (ZI-EHT) of the global ocean reaches 0.12 PW in the northern WBC band and -0.38 PW in the ACC band respectively. The strong ZI-EHT across the ACC in the global ocean is mainly caused by the southern Indian Ocean. The ZI-EHT in the above two bands accounts for a large portion of the total oceanic heat transport, which may play an important role in regulating the climate. The analysis of vertical structures of the EHT along the 35°N and 45°S section reveals that the oscillating EHT pattern can reach deep in the northern WBC regions and the Agulhas Return Current (ARC) region. It also shows that the strong EHT could reach 600 m in the WBC regions and 1 000min the ARC region, with themaximum mainly located between 100 and 400 mdepth. The results would provide useful information for improving the parameterization scheme inmodels.
The Argo data are used to calculate eddy (turbulence) heat transport (EHT) in the global ocean and analyze its horizontal distribution and vertical structure. We calculate the EHT by averaging all the v',T' profiles within each 2°× 2° bin. The velocity and temperature anomalies are obtained by removing their climatological values from the Argo "instantaneous" values respectively. Through the Student's t-test and an error evaluation, we obtained a total of 87% Argo bins with significant depth-integrated EHTs (D-EHTs). The results reveal a positive-and-negative alternating D-EHT pattern along the western boundary currents (WBC) and Antarctic Circumpolar Current (ACC). The zonally-integrated D-EHT (ZI-EHT) of the global ocean reaches 0.12 PW in the northern WBC band and -0.38 PW in the ACC band respectively. The strong ZI-EHT across the ACC in the global ocean is mainly caused by the southern Indian Ocean. The ZI-EHT in the above two bands accounts for a large portion of the total oceanic heat transport, which may play an important role in regulating the climate. The analysis of vertical structures of the EHT along the 35°N and 45°S section reveals that the oscillating EHT pattern can reach deep in the northern WBC regions and the Agulhas Return Current (ARC) region. It also shows that the strong EHT could reach 600 m in the WBC regions and 1 000min the ARC region, with themaximum mainly located between 100 and 400 mdepth. The results would provide useful information for improving the parameterization scheme inmodels.
2014, 33(1): 48-55.
doi: 10.1007/s13131-014-0427-4
Abstract:
For the application of soil moisture and ocean salinity (SMOS) remotely sensed sea surface salinity (SSS) products, SMOS SSS global maps and error characteristics have been investigated based on quality control information. The results show that the errors of SMOS SSS products are distributed zonally, i.e., relatively small in the tropical oceans, butmuch greater in the southern oceans in the Southern Hemisphere (negative bias) and along the southern, northern and some other oceanic margins (positive or negative bias). The physical elements responsible for these errors include wind, temperature, and coastal terrain and so on. Errors in the southern oceans are due to the bias in an SSS retrieval algorithm caused by the coexisting high wind speed and low temperature; errors along the oceanic margins are due to the bias in a brightness temperature (TB) reconstruction caused by the high contrast between L-band emissivities fromice or land and from ocean; in addition, some other systematic errors are due to the bias in TB observation caused by a radio frequency interference and a radiometer receivers drift, etc. The findings will contribute to the scientific correction and appropriate application of the SMOS SSS products.
For the application of soil moisture and ocean salinity (SMOS) remotely sensed sea surface salinity (SSS) products, SMOS SSS global maps and error characteristics have been investigated based on quality control information. The results show that the errors of SMOS SSS products are distributed zonally, i.e., relatively small in the tropical oceans, butmuch greater in the southern oceans in the Southern Hemisphere (negative bias) and along the southern, northern and some other oceanic margins (positive or negative bias). The physical elements responsible for these errors include wind, temperature, and coastal terrain and so on. Errors in the southern oceans are due to the bias in an SSS retrieval algorithm caused by the coexisting high wind speed and low temperature; errors along the oceanic margins are due to the bias in a brightness temperature (TB) reconstruction caused by the high contrast between L-band emissivities fromice or land and from ocean; in addition, some other systematic errors are due to the bias in TB observation caused by a radio frequency interference and a radiometer receivers drift, etc. The findings will contribute to the scientific correction and appropriate application of the SMOS SSS products.
2014, 33(1): 56-63.
doi: 10.1007/s13131-014-0428-3
Abstract:
Considering the discontinuous characteristics of sea ice on various scales, amodified discrete elementmodel (DEM) for sea ice dynamics is developed based on the granular material rheology. In this modified DEM, a soft sea ice particle element is introduced as a self-adjustive particle size function. Each ice particle can be treated as an assembly of ice floes, with its concentration and thickness changing to variable sizes under the conservation of mass. In this model, the contact forces among ice particles are calculated using a viscous-elastic-plasticmodel, while themaximum shear forces are described with the Mohr-Coulomb friction law. With this modified DEM, the ice flow dynamics is simulated under the drags of wind and current in a channel of various widths. The thick nesses, concentrations and velocities of ice particles are obtained, and then reasonable dynamic process is analyzed. The sea ice dynamic process is also simulated in a vortex wind field. Taking the influence of thermodynamics into account, this modified DEM will be improved in the future work.
Considering the discontinuous characteristics of sea ice on various scales, amodified discrete elementmodel (DEM) for sea ice dynamics is developed based on the granular material rheology. In this modified DEM, a soft sea ice particle element is introduced as a self-adjustive particle size function. Each ice particle can be treated as an assembly of ice floes, with its concentration and thickness changing to variable sizes under the conservation of mass. In this model, the contact forces among ice particles are calculated using a viscous-elastic-plasticmodel, while themaximum shear forces are described with the Mohr-Coulomb friction law. With this modified DEM, the ice flow dynamics is simulated under the drags of wind and current in a channel of various widths. The thick nesses, concentrations and velocities of ice particles are obtained, and then reasonable dynamic process is analyzed. The sea ice dynamic process is also simulated in a vortex wind field. Taking the influence of thermodynamics into account, this modified DEM will be improved in the future work.
2014, 33(1): 64-76.
doi: 10.1007/s13131-014-0425-6
Abstract:
The variation in the Indian Ocean is investigated using Hadley center sea surface temperature (SST) data during the period 1958-2010. All the first empirical orthogonal function (EOF) modes of the SST anomalies (SSTA) in different domains represent the basin-wide warming and are closely related to the Pacific El Niño- Southern Oscillation (ENSO) phenomenon. Further examination suggests that the impact of ENSO on the tropical Indian Ocean is stronger than that on the southern Indian Ocean. The second EOF modes in different domains show different features. It shows a clear east-west SSTA dipole pattern in the tropical Indian Ocean (Indian Ocean dipole, IOD), and a southwest-northeast SSTA dipole in the southern Indian Ocean (Indian Ocean subtropical dipole, IOSD). It is further revealed that the IOSD is also themain structure of the second EOF mode on the whole basin-scale, in which the IOD pattern does not appear. A correlation analysis indicates that an IOSD event observed during the austral summer is highly correlated to the IOD event peaking about 9 months later. One of the possible physical mechanisms underlying this highly significant statistical relationship is proposed. The IOSD and the IOD can occur in sequence with the help of the Mascarene high. The SSTA in the southwestern Indian Ocean persists for several seasons after themature phase of the IOSD event, likely due to the positive wind-evaporation-SST feed back mechanism. The Mascarene high will be weakened or intensified by this SSTA, which can affect the atmosphere in the tropical region by teleconnection. The pressure gradient between the Mascarene high and themonsoon trough in the tropical Indian Ocean increases (decreases). Hence, an anticyclone (cyclone) circulation appears over the Arabian Sea-India continent. The easterly or westerly anomalies appear in the equatorial Indian Ocean, inducing the onset stage of the IOD. This study shows that the SSTA associated with the IOSD can lead to the onset of IOD with the aid of atmosphere circulation and also explains why some IOD events in the tropical tend to be followed by IOSD in the southern Indian Ocean.
The variation in the Indian Ocean is investigated using Hadley center sea surface temperature (SST) data during the period 1958-2010. All the first empirical orthogonal function (EOF) modes of the SST anomalies (SSTA) in different domains represent the basin-wide warming and are closely related to the Pacific El Niño- Southern Oscillation (ENSO) phenomenon. Further examination suggests that the impact of ENSO on the tropical Indian Ocean is stronger than that on the southern Indian Ocean. The second EOF modes in different domains show different features. It shows a clear east-west SSTA dipole pattern in the tropical Indian Ocean (Indian Ocean dipole, IOD), and a southwest-northeast SSTA dipole in the southern Indian Ocean (Indian Ocean subtropical dipole, IOSD). It is further revealed that the IOSD is also themain structure of the second EOF mode on the whole basin-scale, in which the IOD pattern does not appear. A correlation analysis indicates that an IOSD event observed during the austral summer is highly correlated to the IOD event peaking about 9 months later. One of the possible physical mechanisms underlying this highly significant statistical relationship is proposed. The IOSD and the IOD can occur in sequence with the help of the Mascarene high. The SSTA in the southwestern Indian Ocean persists for several seasons after themature phase of the IOSD event, likely due to the positive wind-evaporation-SST feed back mechanism. The Mascarene high will be weakened or intensified by this SSTA, which can affect the atmosphere in the tropical region by teleconnection. The pressure gradient between the Mascarene high and themonsoon trough in the tropical Indian Ocean increases (decreases). Hence, an anticyclone (cyclone) circulation appears over the Arabian Sea-India continent. The easterly or westerly anomalies appear in the equatorial Indian Ocean, inducing the onset stage of the IOD. This study shows that the SSTA associated with the IOSD can lead to the onset of IOD with the aid of atmosphere circulation and also explains why some IOD events in the tropical tend to be followed by IOSD in the southern Indian Ocean.
2014, 33(1): 77-82.
doi: 10.1007/s13131-014-0420-y
Abstract:
The asymmetry of sea surface temperature anomaly (SSTA) amplitudes between the positive and negative phases of the Indian Ocean dipole (IOD) are studied. The dynamic effects on it are analyzed using a hybrid coordinate ocean model (HYCOM). It suggests that the IOD is still asymmetric even when forced by a symmetric wind stress, and the asymmetry of the SSTA in the eastern pole is strong while that in the western pole is almost insignificant during the mature phase (September-November (SON)). Thus, the IOD asymmetry is primarily caused by the asymmetry in the IODE. A heat budget analysis is also conducted for the mixedlayer temperature in the eastern Indian Ocean (IODE), which indicates that a nonlinear ocean advection cools both the positive and negative IOD events. Therefore, the nonlinear ocean advection is responsible for the asymmetry of the IOD.
The asymmetry of sea surface temperature anomaly (SSTA) amplitudes between the positive and negative phases of the Indian Ocean dipole (IOD) are studied. The dynamic effects on it are analyzed using a hybrid coordinate ocean model (HYCOM). It suggests that the IOD is still asymmetric even when forced by a symmetric wind stress, and the asymmetry of the SSTA in the eastern pole is strong while that in the western pole is almost insignificant during the mature phase (September-November (SON)). Thus, the IOD asymmetry is primarily caused by the asymmetry in the IODE. A heat budget analysis is also conducted for the mixedlayer temperature in the eastern Indian Ocean (IODE), which indicates that a nonlinear ocean advection cools both the positive and negative IOD events. Therefore, the nonlinear ocean advection is responsible for the asymmetry of the IOD.
2014, 33(1): 83-91.
doi: 10.1007/s13131-014-0426-5
Abstract:
Using NCEP short range ensemble forecast (SREF) system, demonstrated two fundamental on-going evolutions in numerical weather prediction (NWP) are through ensemble methodology. One evolution is the shift fromtraditional single-value deterministic forecast to flow-dependent (not statistical) probabilistic forecast to address forecast uncertainty. Another is froma one-way observation-prediction system shifting to an interactive two-way observation-prediction system to increase predictability of a weather system. In the first part, how ensemble spread from NCEP SREF predicting ensemble-mean forecast error was evaluated over a period of about a month. The result shows that the current capability of predicting forecast error by the 21- member NCEP SREF has reached to a similar or even higher level than that of current state-of-the-art NWP models in predicting precipitation, e.g., the spatial correlation between ensemble spread and absolute forecast error has reached 0.5 or higher at 87 h (3.5 d) lead time on average for some meteorological variables. This demonstrates that the current operational ensemble system has already had preliminary capability of predicting the forecast errorwith usable skill,which is a remarkable achievement as of today. Given the good spread-skill relation, the probability derived from the ensemble was also statistically reliable, which is the most important feature a useful probabilistic forecast should have. The second part of this research tested an ensemble-based interactive targeting (E-BIT) method. Unlike other math ematically-calculated objective approaches, thismethod is subjective or human interactive based on information froman ensemble of forecasts. A numerical simulation study was performed to eight real atmospheric cases with a 10-member, bred vector-based mesoscale ensemble using the NCEP regional spectralmodel (RSM, a sub-component of NCEP SREF) to prove the concept of this E-BIT method. The method seems to workmost effective for basic atmospheric state variables, moderately effective for convective instabilities and least effective for precipitations. Precipitation is a complex result of many factors and, therefore, a more challenging field to be improved by targeted observation.
Using NCEP short range ensemble forecast (SREF) system, demonstrated two fundamental on-going evolutions in numerical weather prediction (NWP) are through ensemble methodology. One evolution is the shift fromtraditional single-value deterministic forecast to flow-dependent (not statistical) probabilistic forecast to address forecast uncertainty. Another is froma one-way observation-prediction system shifting to an interactive two-way observation-prediction system to increase predictability of a weather system. In the first part, how ensemble spread from NCEP SREF predicting ensemble-mean forecast error was evaluated over a period of about a month. The result shows that the current capability of predicting forecast error by the 21- member NCEP SREF has reached to a similar or even higher level than that of current state-of-the-art NWP models in predicting precipitation, e.g., the spatial correlation between ensemble spread and absolute forecast error has reached 0.5 or higher at 87 h (3.5 d) lead time on average for some meteorological variables. This demonstrates that the current operational ensemble system has already had preliminary capability of predicting the forecast errorwith usable skill,which is a remarkable achievement as of today. Given the good spread-skill relation, the probability derived from the ensemble was also statistically reliable, which is the most important feature a useful probabilistic forecast should have. The second part of this research tested an ensemble-based interactive targeting (E-BIT) method. Unlike other math ematically-calculated objective approaches, thismethod is subjective or human interactive based on information froman ensemble of forecasts. A numerical simulation study was performed to eight real atmospheric cases with a 10-member, bred vector-based mesoscale ensemble using the NCEP regional spectralmodel (RSM, a sub-component of NCEP SREF) to prove the concept of this E-BIT method. The method seems to workmost effective for basic atmospheric state variables, moderately effective for convective instabilities and least effective for precipitations. Precipitation is a complex result of many factors and, therefore, a more challenging field to be improved by targeted observation.
2014, 33(1): 92-101.
doi: 10.1007/s13131-014-0418-5
Abstract:
Against the background of the currentworld facing an energy crisis, and human beings puzzled by the problems of environment and resources, developing clean energy sources becomes the inevitable choice to deal with a climate change and an energy shortage. A global ocean wave energy resource was reanalyzed by using ERA-40 wave reanalysis data 1957-2002 from European Centre for Medium-Range Weather Forecasts (ECMWF). An effective significant wave height is defined in the development of wave energy resources (short as effective SWH), and the total potential of wave energy is exploratively calculated. Synthetically considering a wave energy density, a wave energy level probability, the frequency of the effective SWH, the stability and long-termtrend of wave energy density, a swell index and a wave energy storage, global ocean wave energy resources were reanalyzed and regionalized, providing reference to the development of wave energy resources such as wave power plant location, seawater desalination, heating, pumping.
Against the background of the currentworld facing an energy crisis, and human beings puzzled by the problems of environment and resources, developing clean energy sources becomes the inevitable choice to deal with a climate change and an energy shortage. A global ocean wave energy resource was reanalyzed by using ERA-40 wave reanalysis data 1957-2002 from European Centre for Medium-Range Weather Forecasts (ECMWF). An effective significant wave height is defined in the development of wave energy resources (short as effective SWH), and the total potential of wave energy is exploratively calculated. Synthetically considering a wave energy density, a wave energy level probability, the frequency of the effective SWH, the stability and long-termtrend of wave energy density, a swell index and a wave energy storage, global ocean wave energy resources were reanalyzed and regionalized, providing reference to the development of wave energy resources such as wave power plant location, seawater desalination, heating, pumping.
2014, 33(1): 102-108.
doi: 10.1007/s13131-014-0423-8
Abstract:
The relationships among an ocean wave spectrum, a fully polarimetric coherence matrix, and radar parameters are deduced with an electromagnetic wave theory. Furthermore, the relationship between the polarimetric entropy and ocean wave spectrumis established based on the definition of entropy and a twoscale scattering model of the ocean surface. It is the first time that the polarimetric entropy of the ocean surface is presented in theory. Meanwhile, the relationships among the fully polarimetric entropy and the parameters related to radar and ocean are discussed. The study is the basis of further monitoring targets on the ocean surface and deriving oceanic information with the entropy from the ocean surface. The contrast enhancement between human-made targets and the ocean surface with the entropy is presented with quad-pol airborne synthetic aperture radar (AIRSAR) data.
The relationships among an ocean wave spectrum, a fully polarimetric coherence matrix, and radar parameters are deduced with an electromagnetic wave theory. Furthermore, the relationship between the polarimetric entropy and ocean wave spectrumis established based on the definition of entropy and a twoscale scattering model of the ocean surface. It is the first time that the polarimetric entropy of the ocean surface is presented in theory. Meanwhile, the relationships among the fully polarimetric entropy and the parameters related to radar and ocean are discussed. The study is the basis of further monitoring targets on the ocean surface and deriving oceanic information with the entropy from the ocean surface. The contrast enhancement between human-made targets and the ocean surface with the entropy is presented with quad-pol airborne synthetic aperture radar (AIRSAR) data.
2014, 33(1): 109-113.
doi: 10.1007/s13131-014-0402-0
Abstract:
HY-2 satellite is the first satellite for dynamic environmental parameters measurement of China, which was launched on 16th August 2011. A scanning microwave radiometer (RM) is carried for sea surface temperature (SST), sea surface wind speed, columnar water vapor and columnar cloud liquid water detection. In this paper, the initial SST product of RM was validated with in-situ data of National Data of Buoy Center (NDBC)mooring and Argo buoy. The validation results indicate the accuracy of RMSST is better than 1.7℃. The comparison of RM SST and WindSat SST shows the former is warmer than the latter at high sea surface wind speed and the difference between these SSTs is depend on the sea surface wind speed. Then, the relationship between the errors of RM SST and sea surface wind speed was analyzed using NDBC mooring measurements. Based on the results of assessment and errors analysis, the suggestions of taking account of the affection of sea surface wind speed and using sea surface wind speed and direction derived from the microwave scatteromter aboard on HY-2 for SST product calibration were given for retrieval algorithm improvement.
HY-2 satellite is the first satellite for dynamic environmental parameters measurement of China, which was launched on 16th August 2011. A scanning microwave radiometer (RM) is carried for sea surface temperature (SST), sea surface wind speed, columnar water vapor and columnar cloud liquid water detection. In this paper, the initial SST product of RM was validated with in-situ data of National Data of Buoy Center (NDBC)mooring and Argo buoy. The validation results indicate the accuracy of RMSST is better than 1.7℃. The comparison of RM SST and WindSat SST shows the former is warmer than the latter at high sea surface wind speed and the difference between these SSTs is depend on the sea surface wind speed. Then, the relationship between the errors of RM SST and sea surface wind speed was analyzed using NDBC mooring measurements. Based on the results of assessment and errors analysis, the suggestions of taking account of the affection of sea surface wind speed and using sea surface wind speed and direction derived from the microwave scatteromter aboard on HY-2 for SST product calibration were given for retrieval algorithm improvement.
2014, 33(1): 114-119.
doi: 10.1007/s13131-014-0403-z
Abstract:
A scanning microwave radiometer (RM) was launched on August 16, 2011, on board HY-2 satellite. The six-month long global sea surface wind speeds observed by the HY-2 scanning microwave radiometer are preliminarily validated using in-situ measurements and WindSat observations, respectively, from January to June 2012. The wind speed root-mean-square (RMS) difference of the comparisons with in-situ data is 1.89 m/s for the measurements of NDBC and 1.72 m/s for the recent four-month data measured by PY30-1 oil platform, respectively. On a global scale, the wind speeds of HY-2 RMare compared with the sea surface wind speeds derived from WindSat, the RMS difference of 1.85 m/s for HY-2 RM collocated observations data set is calculated in the same period as above. With analyzing the global map of a mean difference between HY-2 RM and WindSat, it appears that the bias of the sea surface wind speed is obviously higher in the inshore regions. In the open sea, there is a relatively higher positive bias in the mid-latitude regions due to the overestimation of wind speed observations, while the wind speeds are underestimated in the Southern Ocean by HY-2 RMrelative to WindSat observations.
A scanning microwave radiometer (RM) was launched on August 16, 2011, on board HY-2 satellite. The six-month long global sea surface wind speeds observed by the HY-2 scanning microwave radiometer are preliminarily validated using in-situ measurements and WindSat observations, respectively, from January to June 2012. The wind speed root-mean-square (RMS) difference of the comparisons with in-situ data is 1.89 m/s for the measurements of NDBC and 1.72 m/s for the recent four-month data measured by PY30-1 oil platform, respectively. On a global scale, the wind speeds of HY-2 RMare compared with the sea surface wind speeds derived from WindSat, the RMS difference of 1.85 m/s for HY-2 RM collocated observations data set is calculated in the same period as above. With analyzing the global map of a mean difference between HY-2 RM and WindSat, it appears that the bias of the sea surface wind speed is obviously higher in the inshore regions. In the open sea, there is a relatively higher positive bias in the mid-latitude regions due to the overestimation of wind speed observations, while the wind speeds are underestimated in the Southern Ocean by HY-2 RMrelative to WindSat observations.
2014, 33(1): 120-126.
doi: 10.1007/s13131-014-0375-z
Abstract:
High resolution optical satellite imageries containing the sun glitter, similar to synthetic aperture radar (SAR) imageries, are useful in identifying and mapping of bottom topography in shallow waters. The errors in the previous studies are corrected, and a method for mapping submarine bottom topography is developed using the sun glitter satellite imagery. The method is established on the basis of empirical description of a sand wave using an equation with two unknowns named r and k. In order to determine r and k, a "trial and error" approach is introduced and testified by a case study on the Taiwan Banks using an ASTER imagery. The results show that the inversed water depths match wellwith the sounding water depths. The agreement between the inversed results and the in situmeasurements is about 78% by comparing 371 points. Moreover, this method has the advantage in keeping the original appearance of a sand wave, especially in positions around the sand wave crest. The fine agreement indicates that the imaging model is flexible and the approach developed is feasible.
High resolution optical satellite imageries containing the sun glitter, similar to synthetic aperture radar (SAR) imageries, are useful in identifying and mapping of bottom topography in shallow waters. The errors in the previous studies are corrected, and a method for mapping submarine bottom topography is developed using the sun glitter satellite imagery. The method is established on the basis of empirical description of a sand wave using an equation with two unknowns named r and k. In order to determine r and k, a "trial and error" approach is introduced and testified by a case study on the Taiwan Banks using an ASTER imagery. The results show that the inversed water depths match wellwith the sounding water depths. The agreement between the inversed results and the in situmeasurements is about 78% by comparing 371 points. Moreover, this method has the advantage in keeping the original appearance of a sand wave, especially in positions around the sand wave crest. The fine agreement indicates that the imaging model is flexible and the approach developed is feasible.
2014, 33(1): 127-134.
doi: 10.1007/s13131-014-0422-9
Abstract:
Temperature and relative humidity profiles derived from two China-made global positioning system (GPS) radiosondes (GPS-TK and CF-06-A) during the east tropical Indian Ocean (ETIO) experiment were compared with Vaisala RS92-SGP to assess the performances of China-made radiosondes over the tropical ocean. The results show that there have relative large biases in temperature observations between the GPSTK and the RS92-SGP in the low troposphere, with a warmbias of greater than 2 K in the day and a cooling bias of 0.6 K at night. The temperature differences of the CF-06-A were small in the troposphere both in daytime and nighttime, and became large peak-to-peak fluctuations in the stratosphere. The intercomparison of the relative humidity showed that the CF-06-A had large random errors due to the limitation of sensors and the lack of correction scheme, and the GPS-TK had large systematic biases in the low troposphere which might be related to the temperature impact. GPS height measurements are clearly suitable for China-made radiosonde systems operation. At night, the CF-06-A and the GPS-TK could provide virtual potential temperature and atmospheric boundary layer height measurements of suitable quality for both weather and climate research. As a result of the intercomparison experiment, major errors in the Chinamade radiosonde systems were well indentified and subsequently rectified to ensure improving accuracy for historical and future radiosondes.
Temperature and relative humidity profiles derived from two China-made global positioning system (GPS) radiosondes (GPS-TK and CF-06-A) during the east tropical Indian Ocean (ETIO) experiment were compared with Vaisala RS92-SGP to assess the performances of China-made radiosondes over the tropical ocean. The results show that there have relative large biases in temperature observations between the GPSTK and the RS92-SGP in the low troposphere, with a warmbias of greater than 2 K in the day and a cooling bias of 0.6 K at night. The temperature differences of the CF-06-A were small in the troposphere both in daytime and nighttime, and became large peak-to-peak fluctuations in the stratosphere. The intercomparison of the relative humidity showed that the CF-06-A had large random errors due to the limitation of sensors and the lack of correction scheme, and the GPS-TK had large systematic biases in the low troposphere which might be related to the temperature impact. GPS height measurements are clearly suitable for China-made radiosonde systems operation. At night, the CF-06-A and the GPS-TK could provide virtual potential temperature and atmospheric boundary layer height measurements of suitable quality for both weather and climate research. As a result of the intercomparison experiment, major errors in the Chinamade radiosonde systems were well indentified and subsequently rectified to ensure improving accuracy for historical and future radiosondes.
2014, 33(1): 135-140.
doi: 10.1007/s13131-014-0432-7
Abstract:
Research of interaction mechanism between Chlorella vulgaris and two bacterial strains (Z-QD08 and Z-QS01) were conducted under laboratory conditions. Growth rates of bacteria and C. vulgaris were tested under co-culture conditions to evaluate the effects of concentrations of C. vulgaris and bacteria on their interactions. To test whether the availability of inorganic nutrients, vitamins and trace metals affects the interactions between C. vulgaris and bacteria, experiments were performed with or without the culture medium filtrate of C. vulgaris or bacteria. The results showed that the growth of C. vulgaris was promoted at low concentrations of bacteria (5×106 cells/ml), and expressed a positive correlation with the bacteria density, whereas opposite trend was observed for treatments with high bacteria density (10×106 cells/ml and 20×106 cells/ml). The growth rate of bacteria decreased with the increasing concentrations of C. vulgaris. The growth of bacteria Z-QD08 was inhibited by C. vulgaris through interference competition, while the mechanism for interaction between bacteria Z-QS01 and C. vulgaris was resource competition. The influence of cell density on the interaction between microalgae and bacteria was also discussed. These experiments confirmsome elements of published theory on interactions between heterotrophic bacteria and microalgae and suggest that heterotrophic bacteria play an important role in the development of blooms in natural waters.
Research of interaction mechanism between Chlorella vulgaris and two bacterial strains (Z-QD08 and Z-QS01) were conducted under laboratory conditions. Growth rates of bacteria and C. vulgaris were tested under co-culture conditions to evaluate the effects of concentrations of C. vulgaris and bacteria on their interactions. To test whether the availability of inorganic nutrients, vitamins and trace metals affects the interactions between C. vulgaris and bacteria, experiments were performed with or without the culture medium filtrate of C. vulgaris or bacteria. The results showed that the growth of C. vulgaris was promoted at low concentrations of bacteria (5×106 cells/ml), and expressed a positive correlation with the bacteria density, whereas opposite trend was observed for treatments with high bacteria density (10×106 cells/ml and 20×106 cells/ml). The growth rate of bacteria decreased with the increasing concentrations of C. vulgaris. The growth of bacteria Z-QD08 was inhibited by C. vulgaris through interference competition, while the mechanism for interaction between bacteria Z-QS01 and C. vulgaris was resource competition. The influence of cell density on the interaction between microalgae and bacteria was also discussed. These experiments confirmsome elements of published theory on interactions between heterotrophic bacteria and microalgae and suggest that heterotrophic bacteria play an important role in the development of blooms in natural waters.
