基于浮标、NCEP2及OAFlux产品的新海表感热和潜热通量对比分析

New satellite-derived latent and sensible heat fluxes are performed by using Wind Sat wind speed, Wind Sat sea surface temperature, the European Centre for Medium-range Weather Forecasting(ECMWF) air humidity, and ECMWF air temperature from 2004 to 2014. The 55 moored buoys are used to validate them by using the 30 min and 25 km collocation window. Furthermore, the objectively analyzed air-sea heat fluxes(OAFlux) products and the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis 2(NCEP2) products are also used for global comparisons. The mean biases of sensible and latent heat fluxes between Wind Sat flux results and buoy flux data are –0.39 and –8.09 W/m~2, respectively. In addition, the rootmean-square(RMS) errors of the sensible and latent heat fluxes between them are 5.53 and 24.69 W/m~2,respectively. The RMS errors of sensible and latent heat fluxes are observed to gradually increase with an increasing buoy wind speed. The difference shows different characteristics with an increasing sea surface temperature, air humidity, and air temperature. The zonal average latent fluxes have some high regions which are mainly located in the trade wind zones where strong winds carry dry air in January, and the maximum value centers are found in the eastern waters of Japan and on the US east coast. Overall, the seasonal variability is pronounced in the Indian Ocean, the Pacific Ocean, and the Atlantic Ocean. The three sensible and latent heat fluxes have similar latitudinal dependencies; however, some differences are found in some local regions.     

Annual and Seasonal Variations of the Sea Surface Heat Fluxes in the East Asian Marginal Seas

Based on the twice-daily marine atmospheric variables which were derived mostly from the weather maps for 18 years period from 1978 to 1995, the surface heat flux over the East Asian marginal seas was calculated at 0.5°×0.5° grid points twice a day. The annual mean distribution of the net heat flux shows that the maximum heat loss occurs in the central part of the Yellow Sea, along the Kuroshio axis and along the west coast of the northern Japanese islands. The area off Vladivostok turned out to be a heat-losing region, however, on the average, the amount of heat loss is minimum over the study area and the estuary of the Yangtze River also appears as a region of the minimum heat loss. The seasonal variations of heat flux show that the period of heat gain is longest in the Yellow Sea, and the maximum heat gain occurs in June. The maximum heat loss occurs in January over the study area, except the Yellow Sea where the heat loss is maximum in December. The annual mean value of the net heat flux in the East/Japan Sea is −108 W/m² which is about twice the value of Hirose et al. (1996) or about 30% higher than Kato and Asai (1983). For the Yellow Sea, it is about −89 W/m² and it becomes −75 W/m² in the East China Sea. This increase in values of the net heat flux comes mostly from the turbulent fluxes which are strongly dependent on the wind speed, which fluctuates largely during the winter season. This revised version was published online in August 2006 with corrections to the Cover Date.     

Evaluation of marine surface winds observed by SeaWinds and AMSR on ADEOS-II

Marine surface winds observed by two microwave sensors, SeaWinds and Advanced Microwave Scanning Radiometer (AMSR), on the Advanced Earth Observing Satellite-II (ADEOS-II) are evaluated by comparison with off-shore moored buoy observations. The wind speed and direction observed by SeaWinds are in good agreement with buoy data with root-mean-squared (rms) differences of approximately 1 m s⁻¹ and 20°, respectively. No systematic biases depending on wind speed or cross-track wind vector cell location are discernible. The effects of oceanographic and atmospheric environments on the scatterometry are negligible. Though the wind speed observed by AMSR also showed agreement with buoy observations with rms difference of 1.27 m s⁻¹, the AMSR wind speed is systematically lower than the buoy data for wind speeds lower than 5 m s⁻¹. The AMSR wind seems to have a discontinuous trend relative to the buoy data at wind speeds of 5–6 m s⁻¹. Similar results have been obtained in an intercomparison of wind speeds globally observed by SeaWinds and AMSR on the same orbits. A global wind speed histogram of the AMSR wind shows skewed features in comparison with those of SeaWinds and European Centre for Medium-range Weather Forecasts (ECMWF) analyses.     

Evidence for the Trapping and Amplification of Near-Inertial Motions in a Large Anticyclonic Ring in the Oyashio

Three ARGOS drift buoys were deployed in the Oyashio Current off the Kuril Islands near 45°N in fall, 1990, during a joint Russia/Canada study of western boundary current dynamics in the Subarctic Pacific Ocean. We here report on one buoy deployed within an anticyclonic warm core ring (WCR86B) which shows evidence of large amplitude inertial motions of near-diurnal frequency. During its first week within the ring the buoy drifted with a mean azimuthal current speed of 0.40–0.45 m s⁻¹ and a radius of rotation of 15–20 km. However, superimposed on the mean rotation of the ring at this time were “loops” of near-diurnal period, radius 7–8 km and speeds exceeding 1 m s⁻¹. During successive rotations the buoy spiraled outward, its mean period of rotation increased and the amplitude of the near-diurnal motions decreased. The large motions are explained by inertial wave trapping and amplification within the extremely large and weakly stratified eddy, wherein the negative vorticity of the eddy reduces the local inertial frequency to near-diurnal frequency. We here suggest that either tidal or wind forcing may generate these high-amplitude “loop” motions. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Kuroshio East of Taiwan and in the East China Sea and the currents East of Ryukyu Islands during early summer of 1996

Using hydrographic data and moored current meter records and the ADCP observed current data during May–June 1996, a modified inverse method is applied to calculate the Kuroshio east of Taiwan and in the East China Sea and the currents east of Ryukyu Islands. There are three branches of the Kuroshio east of Taiwan. The Kuroshio in the East China Sea comes from the main (first) and second branches of the Kuroshio east of Taiwan. The easternmost (third) branch of the Kuroshio flows northeastward to the region east of Ryukyu Islands. The net northward volume transports of the Kuroshio through Section K₂ southeast of Taiwan and Section PN in the East China Sea are 44.4×10⁶ and 27.2×10⁶ m³s⁻¹, respectively. The western boundary current east of Ryukyu Islands comes from the easternmost branch of the Kuroshio east of Taiwan and an anticyclonic recirculating gyre more east, making volume transports of 10 to 15×10⁶ m³s⁻¹. At about 21°N, 127°E southeast of Taiwan, there is a cold eddy which causes branching of the Kuroshio there.     

2016年夏季北冰洋浮冰站近地层辐射和湍流通量观测

2016年8月7－14日中国第七次北极科学考察期间,在83°N附近设立的长期浮冰站开展了辐射和湍流通量观测研究。结果表明,观测期间反照率变化范围为0.64~0.92,平均反照率为0.78;基于现场观测数据评估了PW79、HIRHAM、ARCSYM和CCSM3 4种不同复杂度的反照率参数化方案在天气尺度的表现,最为复杂的CCSM3结果优于其他参数化方案,但不能体现降雪条件下的反照率快速增长。浮冰区冰雪面平均净辐射为18.10 W/m2,平均感热通量为1.73 W/m2,平均潜热通量为5.55 W/m2,海冰表面消融率为（0.30±0.22） cm/d,表明此时北冰洋浮冰正处于快速消融期。冰面的平均动量通量为0.098（kg·m/s）/（m2·s）,动量通量与风速有很好的对应关系,相关系数达0.80。     

Heart transport by currents and thermal balance of the south-eastern Indian Ocean active layer

The paper shows that, by virtue of the specific water circulation in the south-eastern Indian Ocean, thermal influx within the 0–200 m layer exceeds the efflux by 13.5×10¹⁵ MJ per year, which, being recalculated for the entire area, is equivalent to about 2200 MJ m⁻². Computations of the heat fluxes through the sea surface in that part of the ocean indicate that thermal efflux to the atmosphere is larger than the influx of solar heat by about 1500 (on average, for the entire area), rather than by 2200 MJ m⁻² per year. Hence, about 700 MJm⁻² penetrate through the lower boundary of the layer and warm up the deeper ocean layers. Translated by Vladimir A. Puchkin.     

Surface heat fluxes during hot events

We selected surface flux datasets to investigate the heat fluxes during “hot events”; (HEs), defined as short-term, large-scale phenomena involving very high sea surface temperature (SST). Validation of the heat fluxes against in-situ ones, which are estimated from in-situ observation in HE sampling conditions, shows the accuracies (bias ± RMS error) of net shortwave radiation, net long wave radiation, latent heat and sensible heat fluxes are 20 ± 45.0 W m⁻², −9 ± 12.3 W m⁻², −2.3 ± 31.5 W m⁻² and 1.5 ± 5.0 W m⁻², respectively. Statistical analyses of HEs show that, during these events, net solar radiation remains high and then decreases from 246 to 220 W m⁻², while latent heat is low and then increases from 100 W m⁻² to 124 W m⁻². Histogram peaks indicate net solar radiation of 270 W m⁻² and latent heat flux of 90 W m⁻² during HEs. Further, HEs are shown to evolve in three phases: formation, mature, and ending phases. Mean heat gain (HG) in the HE formation phase of 60 W m⁻² is larger than the reasonably estimated annual mean HG range of 0–25 W m⁻² in the Indo-Pacific Warm Pool. Such large daily HG in the HE formation phase can be expected to increase SSTs and produce large amplitudes of diurnal SST variations during HEs, which have been observed by both satellite and in-situ measurements in our previous studies.     

Outbreak of warm water from the Kuroshio South of Japan

During the concentrated observation (April–May 1988) conducted as a part of the Ocean Mixed Layer Experiment (OMLET) in the sea area south of Japan, a conspicuous outbreak of warm water occurred from the large-meander region of the Kuroshio toward the southwest in the direction of the former Ocean Weather Station “T”. A series of NOAA-AVHRR infrared images clearly showed the process of this event. A surface buoy-mooring system deployed in this experiment recorded the arrival of this outbreak of water, in terms of the rise of sea-surface temperature (SST) of 1.5°C and the flow of warm water of 1.5kt toward the northwest at “T”. We studied this phenomenon by combining time series of infrared SST images with the oceanographic data obtained by two research vessels. The warm water was about 100 m deep in the section at 137°E along the edge of the Off-Shikoku Warm Water. It was estimated that about twenty outbreaks of this kind in a year can compensate a large heat loss to the atmosphere above this ocean region.     

Seasonal variations of wind and waves over Taiwan waters

We here investigate the frequency and intensity of oscillations in oceanographic data within intraseasonal time scales using spectral analysis of surface wind and wave time-series data collected at off-island weather stations or moored buoys around Taiwan. Data from marine weather stations were used to trace atmospheric conditions, while we used buoy data to examine sea states. The spectra and wavelet scalogram of the wind fields revealed oscillations with a period of around 20–33 days, and the energy density of the wind field at the off-island stations was stronger than that at the data buoy stations. However, the wavelet scalogram of the wave height measured at the buoy stations was stronger than its associated wind field. This long-period oscillation is consistent with the wavelet scalogram of the wind field calculated from the off-island weather stations. About 20–33 day oscillations exist within intraseasonal variations, which are closely linked to the atmospheric environment and to wind and ocean wave fields. Oscillations with a period of 5–10 days are a pronounced feature over northeastern Taiwan waters during the winter season and can be interpreted as the wave pattern following synoptic weather systems.     

Accumulation and Export of Dissolved Organic Carbon in Surface Waters of Subtropical and Tropical Pacific Ocean

Dissolved organic carbon (DOC) concentrations in surface waters of the Pacific Ocean during October–November, 1995, were determined using a high-temperature combustion method. The DOC in the surface mixed-layer was approximately homogeneous with a concentration between 55 and 89 μmol C l⁻¹. This homogeneity indicates that there is a strong control of the vertical distribution of DOC by mixing processes. The DOC concentrations in the mixed-layer in the subtropical region were up to 27 μmol C l⁻¹ higher than in the tropical region. This difference reflects the subtropical accumulation and the tropical export of DOC. There is a significant positive correlation between DOC and chlorophyll a concentrations in the mixed-layer of the North Pacific subtropical region, suggesting that phytoplankton is the primary source of DOC accumulated in this region. Calculations using simple box models suggest that DOC export in the tropical region (0–50 m depth, 10°N-10°S, along 160°W) occurs primarily by poleward advection at a rate of 0.5–3 mmol C m⁻²day⁻¹. A comparison with estimates of the export rate of particulate organic carbon published in previous studies leads us to conclude that DOC export may contribute less to the carbon budget in the tropical region than has recently been supposed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Oxygen Utilization and Organic Carbon Remineralization in the Upper Water Column of the Pacific Ocean

As a part of the JGOFS synthesis and modeling project, researchers have been working to synthesize the WOCE/JGOFS/DOE/NOAA global CO₂ survey data to better understand carbon cycling processes in the oceans. Working with international investigators we have compiled a Pacific Ocean data set with over 35,000 unique samples analyzed for at least two carbon species, oxygen, nutrients, chlorofluorocarbon (CFC) tracers, and hydrographic parameters. We use these data here to estimate in-situ oxygen utilization rates (OUR) and organic carbon remineralization rates within the upper water column of the Pacific Ocean. OURs are derived from the observed apparent oxygen utilization (AOU) and the water age estimates based on CFCs in the upper water and natural radiocarbon in deep waters. The rates are generally highest just below the euphotic zone and decrease with depth to values that are much lower and nearly constant in water deeper than 1200 m. OURs ranged from about 0.02–10 μmol kg⁻¹yr⁻¹ in the upper water masses from about 100–1000 m, and averaged = 0.10 μmol kg⁻¹yr⁻¹ in deep waters below 1200 m. The OUR data can be used to directly estimate organic carbon remineralization rates using the C:O Redfield ratio given in Anderson and Sarmiento (1994). When these rates are integrated we obtain an estimate of 5.3 ± 1 Pg C yr⁻¹ for the remineralization of organic carbon in the upper water column of the Pacific Ocean. This revised version was published online in July 2006 with corrections to the Cover Date.     

Atmospheric input of trace elements to the western Pacific Ocean and the Kuroshio ocean area

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Formation, Distribution and Volume Transport of the North Pacific Intermediate Water Studied by Repeat Hydrographic Observations

In order to examine the formation, distribution and transport of North Pacific Intermediate Water (NPIW), repeated hydrographic observations along several lines in the western North Pacific were carried out in the period from 1996 to 2001. NPIW formation can be described as follows: (1) Oyashio water extends south of the Subarctic Boundary and meets Kuroshio water in intermediate layers; (2) active mixing between Oyashio and Kuroshio waters occurs in intermediate layers; (3) the mixing of Oyashio and Kuroshio waters and salinity minimum formation around the potential density of 26.8σ_θ proceed to the east. It is found that Kuroshio water flows eastward even in the region north of 40°N across the 165°E line, showing that Kuroshio water extends north of the Subarctic Boundary. Volume transports of Oyashio and Kuroshio components (relative to 2000 dbar) integrated in the potential density range of 26.6–27.4σθ along the Kuroshio Extension across 152°E–165°E are estimated to be 7–8 Sv (10⁶ m³s⁻¹) and 9–10 Sv, respectively, which is consistent with recent work. This revised version was published online in July 2006 with corrections to the Cover Date.     

Path and volume transport of the Kuroshio current in Sagami Bay and their relationship to cold water masses near Izu Peninsula

The path of the Kuroshio in Sagami Bay was surveyed through drifter tracking from Oshima-West Channel to Oshima-East Channel. A subsurface drifter with a drogue at 300 m depth flowed around Oshima from Oshima-West Channel to Oshima-East Channel. A difference in flow directions between the upper and lower layers was apparent in the northwest of Oshima. Flow directions there were shown to change from north in the surface layer to east in the bottom layer, and this was confirmed with moored currentmeters.A profile of northward current velocity was estimated from measurements in six layers with currentmeters deployed in the Oshima-West Channel. The profile shows a core of northward flow along the eastern bottom slope and a weak southward flow along the western bottom slope. Volume transport of the Kuroshio into Sagami Bay was estimated to be 1.8×10⁶m³sec^–1 from the profile.Long-term current measurement showed that southward flows were observed in Oshima-West Channel in July 1977, May 1978 and April 1979. Cold or warm water masses appearing south of the Izu Peninsula are suggested to have caused the changes.Displacement of the cold water mass in July 1977 is discussed on the basis of current measurements and offshore oceanographic conditions.     

西太平洋秋季130°E断面有色溶解有机物的分布特征及光降解行为研究

对2018年秋季西太平洋130°E断面上层水体有色溶解有机物(CDOM)的光学特性及光降解行为进行了研究。结果表明,西太平洋上层水体CDOM的吸收系数a(320)变化范围为0.025～0.64 m?1,平均值为(0.20±0.08) m?1;a(320)在表层相对较低,主要与表层CDOM的光漂白去除有关;在100～200 m水层较高,主要与次表层的生物活动有关。利用三维荧光光谱?平行因子分析技术,识别出两种荧光组分:类酪氨酸组分C1和海洋类腐殖质组分C2。C1主要源于棉兰老冷涡?上升流所带来的营养物质对浮游植物生产活动和微生物活动的促进作用;C2主要源于黑潮所带来的海洋类腐殖的输入。光化学降解实验发现,CDOM吸收值的损失主要发生在紫外波段;光照60 h后,类酪氨酸组分相较于海洋类腐殖质组分更易发生光降解;且光降解是西太平洋海域CDOM的重要去除途径。     

基于中国北极考察布放浮标观测和数值模拟的海冰和积雪厚度变化分析

Sea ice and the snow pack on top of it were investigated using Chinese National Arctic Research Expedition(CHINARE) buoy data.Two polar hydrometeorological drifters,known as Zeno? ice stations,were deployed during CHINARE 2003.A new type of high-resolution Snow and Ice Mass Balance Arrays,known as SIMBA buoys,were deployed during CHINARE 2014.Data from those buoys were applied to investigate the thickness of sea ice and snow in the CHINARE domain.A simple approach was applied to estimate the average snow thickness on the basis of Zeno~ temperature data.Snow and ice thicknesses were also derived from vertical temperature profile data based on the SIMBA buoys.A one-dimensional snow and ice thermodynamic model(HIGHTSI) was applied to calculate the snow and ice thickness along the buoy drift trajectories.The model forcing was based on forecasts and analyses of the European Centre for Medium-Range Weather Forecasts(ECMWF).The Zeno~ buoys drifted in a confined area during 2003–2004.The snow thickness modelled applying HIGHTSI was consistent with results based on Zeno~ buoy data.The SIMBA buoys drifted from 81.1°N,157.4°W to 73.5°N,134.9°W in 15 months during2014–2015.The total ice thickness increased from an initial August 2014 value of 1.97 m to a maximum value of2.45 m before the onset of snow melt in May 2015;the last observation was approximately 1 m in late November2015.The ice thickness based on HIGHTSI agreed with SIMBA measurements,in particular when the seasonal variation of oceanic heat flux was taken into account,but the modelled snow thickness differed from the observed one.Sea ice thickness derived from SIMBA data was reasonably good in cold conditions,but challenges remain in both snow and ice thickness in summer.     

国内外海洋资料浮标技术现状与发展

海洋资料浮标是长期连续进行海洋监测的主要手段之一。本文简单介绍了国内外海洋资料浮标技术的现状与发展及浮标在我国海洋监测中的应用情况,提出了我国资料浮标技术的研究与发展设想。     

Numerical study of baroclinic tides in Luzon Strait

The spatial and temporal variations of baroclinic tides in the Luzon Strait (LS) are investigated using a three-dimensional tide model driven by four principal constituents, O₁, K₁, M₂ and S₂, individually or together with seasonal mean summer or winter stratifications as the initial field. Barotropic tides propagate predominantly westward from the Pacific Ocean, impinge on two prominent north-south running submarine ridges in LS, and generate strong baroclinic tides propagating into both the South China Sea (SCS) and the Pacific Ocean. Strong baroclinic tides, ∼19 GW for diurnal tides and ∼11 GW for semidiurnal tides, are excited on both the east ridge (70%) and the west ridge (30%). The barotropic to baroclinic energy conversion rate reaches 30% for diurnal tides and ∼20% for semidiurnal tides. Diurnal (O₁ and K₁) and semidiurnal (M₂) baroclinic tides have a comparable depth-integrated energy flux 10–20 kW m⁻¹ emanating from the LS into the SCS and the Pacific basin. The spring-neap averaged, meridionally integrated baroclinic tidal energy flux is ∼7 GW into the SCS and ∼6 GW into the Pacific Ocean, representing one of the strongest baroclinic tidal energy flux regimes in the World Ocean. About 18 GW of baroclinic tidal energy, ∼50% of that generated in the LS, is lost locally, which is more than five times that estimated in the vicinity of the Hawaiian ridge. The strong westward-propagating semidiurnal baroclinic tidal energy flux is likely the energy source for the large-amplitude nonlinear internal waves found in the SCS. The baroclinic tidal energy generation, energy fluxes, and energy dissipation rates in the spring tide are about five times those in the neap tide; while there is no significant seasonal variation of energetics, but the propagation speed of baroclinic tide is about 10% faster in summer than in winter. Within the LS, the average turbulence kinetic energy dissipation rate is O(10⁻⁷) W kg^{− 1} and the turbulence diffusivity is O(10⁻³) m²s⁻¹, a factor of 100 greater than those in the typical open ocean. This strong turbulence mixing induced by the baroclinic tidal energy dissipation exists in the main path of the Kuroshio and is important in mixing the Pacific Ocean, Kuroshio, and the SCS waters.     

福岛核事故泄漏入海的137Cs长期输运的数值研究

The Fukushima nuclear accident in 2011 released large amounts of radionuclides, including ~(137)Cs, into the Pacific Ocean. A quasi-global ocean radioactive transport model with horizontal grid spacing of 0.5°×0.5° and 21 vertical layers was thereafter established to study the long-term transport of the Fukushima-derived ~(137)Cs in the ocean.The simulation shows that the plume of ~(137)Cs would be rapidly transported eastward alongside the Kuroshio Current and its extensions. Contaminated waters with concentrations lower than 2 Bq/m3 would reach the west coast of North America 4 or 5 years after the accident. The ~(137)Cs tends to be carried, despite its very low concentration, into the Indian and South Pacific Oceans by 2016 via various branches of ocean currents.Meanwhile, the ~(137)Cs concentrations in the western part of the North Pacific Ocean decrease rapidly with time. Up to now the highly contaminated waters have remained in the upper 400 m, showing no evidence of significant penetration to deeper layers.