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Variation of Indo-Pacific upper ocean heat content during 2001–2012 revealed by Argo

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Acta Oceanologica Sinica 2015年第5期34卷 29-38页

作者： WU Xiaofen LIU Zenghong LIAO Guanghong WU Lingjuan state Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration north china sea marine forecasting center of state oceanic administration

Understanding of the temporal variation of oceanic heat content （OHC） is of fundamental importance to the prediction of climate change and associated global meteorological phenomena. However, OHC characteristics in the Pacific and Indian oceans are not well understood. Based on in situ ocean temperature and salinity profiles mainly from the Argo program, we estimated the upper layer （0-750 m） OHC in the Indo-Pacific Ocean （40°S-40°N, 30°E-80°W）. Spatial and temporal variability of OHC and its likely physical mechanisms are also analyzed. Climatic distributions of upper-layer OHC in the Indian and Pacific oceans have a similar saddle pattern in the subtropics, and the highest OHC value was in the northern Arabian sea. However, OHC variabilities in the two oceans were different. OHC in the Pacific has an east-west see-saw pattern, which does not appear in the Indian Ocean. In the Indian Ocean, the largest change was around 10°S. The most interesting phenomenon is that, there was a long-term shift of OHC in the Indo-Pacific Ocean during 2001-2012. Such variation coincided with modulation of subsurface temperature/salinity. During 2001-2007, there was subsurface cooling （freshening） nearly the entire upper 400 m layer in the western Pacific and warming （salting） in the eastern Pacific. During 2008-2012, the thermocline deepened in the western Pacific but shoaled in the east. In the Indian Ocean, there was only cooling （upper 150 m only） and freshening （almost the entire upper 400 m） during 2001-2007. The thermocline deepened during 2008-2012 in the Indian Ocean. Such change appeared from the equator to off the equator and even to the subtropics （about 20°N/S） in the two oceans. This long-term change of subsurface temperature/salinity may have been caused by change of the wind field over the two oceans during 2001-2012, in turn modifying OHC.

关键词： ocean heat content temperature and salinity profiles wind forcing Argo Indo-Pacific Ocean

Potential effects of subduction rate in the key ocean on global warming hiatus

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Acta Oceanologica Sinica 2018年第3期37卷 63-68页

作者： CHEN Xingrong LIU Shan CAI Yi ZHANG Shouwen National marine Environmental forecasting center State Oceanic Administration Key Laboratory of Research on marine Hazards forecasting National Marine Environmental Forecasting CenterState Oceanic Administration

In this study, the possible effects of subduction rate on global warming hiatus were investigated using Simple Ocean Data Assimilation（SODA） data. This study first analyzed the characteristics of the temporal and spatial distribution of global subduction rate, which revealed that the north Atlantic meridional overturning circulation region and the Antarctic Circumpolar Current region are the two main sea areas with great subduction *** this basis, four key areas were selected to explore the relationship between the local subduction rate and the global mean sea surface temperature. In addition, the reason for the variations in subduction rate was preliminarily explored. The results show good correspondence of the subduction of the key areas in the north Atlantic meridional overturning the circulation region and the Antarctic Circumpolar Current region to the global warming hiatus, with the former leading by about 10 years. The subduction process may be a physical mechanism by which the north Atlantic overturning circulation and the Antarctic Circumpolar Current act on the stagnation of global warming. Advection effect plays an important role in the variations in subduction in the key regions. In the Antarctic Circumpolar Current region, the magnitude of sea surface wind stress is closely related to the local changes in subduction.

关键词： global warming hiatus sea surface temperature inter-decadal variation subduction rate

Assimilation of High Frequency Radar Data into a Shelf sea Circulation Model

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Journal of Ocean University of china 2014年第4期13卷 572-578页

作者： XU Jiangling HUANG Juan GAO Song CAO Yajing north china sea marine Forecast center of the state oceanic administration

High Frequency(HF) radar current data is assimilated into a shelf sea circulation model based on optimal interpolation(OI) method. The purpose of this work is to develop a real-time computationally highly efficient assimilation method to improve the forecast of shelf current. Since the true state of the ocean is not known, the specification of background error covariance is arduous. Usually, it is assumed or calculated from an ensemble of model states and is kept in constant. In our method, the spatial covariances of model forecast errors are derived from differences between the adjacent model forecast fields, which serve as the forecast tendencies. The assumption behind this is that forecast errors can resemble forecast tendencies, since variances are large when fields change quickly and small when fields change slowly. The implementation of HF radar data assimilation is found to yield good information for analyses. After assimilation, the root-mean-square error of model decreases significantly. Besides, three assimilation runs with variational observation density are implemented. The comparison of them indicates that the pattern described by observations is much more important than the amount of observations. It is more useful to expand the scope of observations than to increase the spatial interval. From our tests, the spatial interval of observation can be 5 times bigger than that of model grid.

关键词： data assimilation current radar shelf circulation model

The influence of ENSO on sea surface temperature variations in the china seas

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Acta Oceanologica Sinica 2013年第9期32卷 21-29页

作者： LIU Na WANG Hui LING Tiejun FENG Licheng Key Laboratory of Research on marine Hazards forecasting National Marine Environmental Forecasting CenterState Oceanic Administration National marine Environmental forecasting center State Oceanic Administration

Positive SST anomalies usually appear in remote ocean such as the china seas during an ENSO event. By analyzing the monthly data of HadISST from 1950 to 2007, it shows that the interannual component of SST anomalies peak approximately 10 months after SST anomalies peak in the eastern equatorial Pacific. As the ENSO event progresses, the positive SST anomalies spread throughout the china seas and eastward along the Kuroshio extension. Atmospheric reanalysis data demonstrate that changes in the net surface heat flux entering into the china seas are responsible for the SST variability. During E1 Nifio, the western north Pacific anticyclone is generated, with anomalous southwester lies prevailing along the East Asian coast. This anticyclone reduces the mean surface wind speed which decreases the surface heat flux and then increases the SST. The delays between the developing of this anticyclone and the south Indian Ocean anticyclone with approximately 3-6 months cause the 2-3 months lag of the surface heat flux between the china seas and the Indian Ocean. The northwestern Pacific anticyclone is the key process bridging the warming in the eastern equatorial Pacific and that in the china seas.

关键词： sea surface temperature china seas ENSO anticyclone

Assessing the benthic habitat quality in the Huanghe(Yellow River) Estuary and its adjacent areas using AMBI and M-AMBI

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Acta Oceanologica Sinica 2014年第9期33卷 117-124页

作者： LUO Xianxiang ZHANG Juan YANG Jianqiang SONG Wenpeng CUI Wenlin Key Laboratory of marine Environment and Ecology Ocean University of China north china sea Branch of state oceanic administration Laboratory of state oceanic administration for marine Spill Oil Identification and Damage Assessment Technology north china sea Monitoring center North China Sea Branch of State Oceanic Administration

The protection of the biological diversity and the maintenance of the regional ecological integrity for the Huanghe （Yellow River） Estuary and its adjacent areas are practically significant and valuable. However, frequent human activities and natural climate changes have caused vigorous disturbances on the ecosystem in these sea areas. An objective assessment on the benthic habitat quality （BHQ） of the Huanghe Estuary and its adjacent areas is conducted, using AZTI＇s marine Biotic Index （AMBI） and multivariate AMBI （M-AMBI） based on the data of macrobenthos in May and August 2011. The results show that both the indices do not correlate significantly, and their assessment results are greatly different. All of the samples assessed using the AMBI were ＂high＂ or ＂good＂, because the ecological group I （EGI） and the ecological group II （EGII） were dominant macrobenthic ecological groups in the research area. Owing to a low species＇ richness and a high individual abundance in some samples, the BHQ levels using the M-AMBI were worse than those of the AMBI. Significant correlations are observed between the M-AMBI, water depth, bottom water salinity and dissolved inorganic nitrogen, thus the M-AMBI could sensitively respond to environmental changes and distinguish influences from uninfluenced stations, but the AMBI could not. The consistent results between the AMBI and the M-AMBI mainly appeared in the uninfluenced （undisturbed or slightly disturbed） sta- tions. Therefore, the M-AMBI is more effective than the AMBI in assessing the benthic habitat quality in the Huanghe Estuary and its adjacent areas. Using the M-AMBI to assess the BHQ of the Huanghe Estuary and its adjacent areas, the results show that 3% of the stations are undisturbed and the BHQs are ＂high＂, and 61% of the stations are slightly disturbed and those of the BHQ are ＂good＂, and the rest are meanly disturbed and those of the BHQ are ＂moderate＂.

关键词： biotic indices AMBI M-AMBI benthic habitat quality Huanghe (Yellow River) Estuary

Temporal and spatial variability of the carbon cycle in the east of china's seas:a three-dimensional physical-biogeochemical modeling study

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Acta Oceanologica Sinica 2017年第3期36卷 60-71页

作者： JI Xuanliang LIU Guimei GAO Shan WANG Hui ZHANG Miaoyin National marine Environmental forecasting center State Oceanic AdministrationBeijing 100081China Key Laboratory of Research on marine Hazards forecasting National Marine Environmental Forecasting CenterState Oceanic AdministrationBeijing 100081China

In the east of china＇s seas, there is a wide range of the continental shelf. The nutrient cycle and the carbon cycle in the east of china＇s seas exhibit a strong variability on seasonal to decadal time scales. On the basis of a regional ocean modeling system（ROMS）, a three dimensional physical-biogeochemical model including the carbon cycle with the resolution（1/12）°×（1/12）° is established to investigate the physical variations, ecosystem responses and carbon cycle consequences in the east of china＇s seas. The ROMS-Nutrient Phytoplankton Zooplankton Detritus（NPZD） model is driven by daily air-sea fluxes（wind stress, long wave radiation, short wave radiation, sensible heat and latent heat, freshwater fluxes） that derived from the National centers for Environmental Prediction（NCEP） reanalysis2 from 1982 to 2005. The coupled model is capable of reproducing the observed seasonal variation characteristics over the same period in the East china sea. The integrated air-sea CO_2 flux over the entire east of china＇s seas reveals a strong seasonal cycle, functioning as a source of CO_2 to the atmosphere from June to October, while serving as a sink of CO_2 to the atmosphere in the other months. The 24 a mean value of airsea CO_2 flux over the entire east of china＇s seas is about 1.06 mol/（m^2·a）, which is equivalent to a regional total of3.22 Mt/a, indicating that in the east of china＇s seas there is a sink of CO_2 to the atmosphere. The partial pressure of carbon dioxide in sea water in the east of china＇s seas has an increasing rate of 1.15 μatm/a（1μtm/a=0.101 325Pa）, but p H in sea water has an opposite tendency, which decreases with a rate of 0.001 3 a^（–1） from 1982 to *** activity is a dominant factor that controls the pCO_2 air in the east of china＇s seas, and followed by a temperature. The inverse relationship between the interannual variability of air-sea CO_2 flux averaged from the domain area and Ni？o3 SST Index indicates that the carbon cycle in the ea

关键词： the east of china's seas physical-biogeochemical model partial pressure of carbon dioxide in sea water air-sea CO2 flux

Interaction of an anticyclonic eddy with sea ice in the western Arctic Ocean:an eddy-resolving model study

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Acta Oceanologica Sinica 2013年第3期32卷 54-62页

作者： LI Qun ZHANG Zhanhai WU Huiding Polar Research Institute of china State Oceanic Administration National marine Environmental forecasting center State Oceanic Administration

The dramatic decline of summer sea ice extent and thickness has been witnessed in the western Arctic Ocean in recent decades, which has motivated scientists to search for possible factors driving the sea ice variability. An eddy-resolving, ice-ocean coupled model covering the entire Arctic Ocean is implemented, with focus on the western Arctic Ocean. Special attention is paid to the summer Maskan coastal current （ACC）, which has a high temperature （up to 5℃ or more） in the upper layer due to the solar radiation over the open water at the lower latitude. Downstream of the ACC after Barrow Point, a surface-intensified anticyclonic eddy is frequently generated and propagate towards the Canada Basin during the summer season when sea ice has retreated away from the coast. Such an eddy has a warm core, and its source is high-temperature ACC water. A typical warm-core eddy is traced. It is trapped just below summer sea ice melt water and has a thickness about 60 m. Temperature in the eddy core reaches 2-3℃, and most water inside the eddy has a temperature over 1℃. With a definition of the eddy boundary, an eddy heat is calculated, which can melt 1 600 km2 of 1 m thick sea ice under extreme conditions.

关键词： eddy-resolving anticyclonic eddy sea ice western Arctic Ocean Alaskan coastal current

Comprehensive analysis of the origin of giant jellyfish near Qinhuangdao in summer

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Chinese Journal of Oceanology and Limnology 2017年第5期35卷 1061-1069页

作者：吴玲娟吴晓芬白涛 north china sea marine forecasting center of state oceanic administration Qingdao 266061 China state Key Laboratory of Satellite Ocean Environment Dynamics Hangzhou 310012 China

A massive bloom of the giant jellyfi sh Nemopilema nomurai occurred in waters off Qinhuangdao,a port city in Hebei Province,in July ***,jellyfi sh larvae were not found in this location during the previous winter and *** determine the possible origin of the giant jellyfi sh medusa in the Bohai sea,we developed a backward particle-tracking model and a series of numerical simulations were conducted by using the hydrodynamic,three-dimensional Regional Ocean Modeling System(ROMS)*** simulated results showed that passive particles,representing jellyfi sh medusae,released in surface waters at diff erent dates during the summer had consistent *** released at the sea surface on August1 and 15 could be traced back to the center of the Bohai sea and to waters between Feiyan Shoal and the new Huanghe(Yellow)River *** released on July 1 and 15 could also be traced back to the center of the Bohai sea and to waters between Feiyan Shoal and only to Zhuangxi tide ***,none of the particles released in the middle and bottom water layers could be traced back to those *** on the results of the numerical simulations,the distribution characteristics of seafl oor sediments,and observational data for giant jellyfi sh in the region,we suggest that waters between Feiyan Shoal and the new Huanghe River estuary are the likely origin of giant jellyfi sh observed near Qinhuangdao in summer.

关键词： backward particle-tracking Bohai sea Lagrangian method giant jellyfish numerical simulation

Three-Dimensional Wave-Induced Current Model Equations and Radiation Stresses

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china Ocean Engineering 2017年第4期31卷 418-427页

作者： XIA Hua-yong South china sea marine Forecast center State Oceanic administrationGuangzhou 510300China

After the approach by Mellor （2003, 2008）, the present paper reports on a repeated effort to derive the equations for three-dimensional wave-induced current. Via the vertical momentum equation and a proper coordinate transformation, the phase-averaged wave dynamic pressure is well treated, and a continuous and depth-dependent radiation stress tensor, rather than the controversial delta Dirac function at the surface shown in Mellor （2008）, is provided. Besides, a phase-averaged vertical momentum flux over a sloping bottom is introduced. All the inconsistencies in Mellor （2003, 2008）, pointed out by Ardhuin et al. （2008） and Bennis and Ardhuin （2011）, are overcome in the presently revised equations. In a test case with a sloping sea bed, as shown in Ardhuin et al. （2008）, the wave-driving forces derived in the present equations are in good balance, and no spurious vertical circulation occurs outside the surf zone, indicating that Airy’s wave theory and the approach of Mellor （2003, 2008） are applicable for the derivation of the wave-induced current model.

关键词： sea surface wave wave-induced current radiation stress vertical wave momentum flux