杭州湾枯季水沙若干特征分析

根据2014年1月及2017年2月杭州湾大、小潮水沙资料,计算了流速、含沙量、单宽潮量、单宽输沙量,进而分析了潮周期断面净潮量、净输沙量和区域冲淤分布。研究发现杭州湾涨、落潮平均流速比值整体较20世纪八九十年代增大,绝大部分区域大于1.0,涨潮流相对增强,澉浦南岸和金山北岸尤为显著。含沙量平面上分布澉浦、杭州湾南岸两个高值区(大潮大于3 kg/m³,小潮大于1.3 kg/m³)以及北岸湾口至乍浦之间的低值区(大潮小于2 kg/m³,小潮小于0.9 kg/m³),随潮汛变化显著,最大含沙量浓度通常滞后于急流时刻。各测站涨、落潮量和输沙量呈现“大涨大落”和“大进大出”的特征,造成杭州湾短时间尺度内的“大冲大淤”。大潮两涨两落金山与乍浦、乍浦与澉浦之间区域净输沙量可达几千万吨,净冲淤则在几百万吨。     

乳糖诱导重组别藻蓝蛋白(rAPC)在大肠杆菌(Escherichia coli)中的表达

采用廉价的乳糖替代IPTG诱导重组别藻蓝蛋白(rAPC)在大肠杆菌(Escherichiacoli)JM109中表达,对诱导产物表达的培养基、培养条件、诱导剂的浓度和诱导时机进行了优化,将优化条件用于5L自控发酵罐进行高密度培养。结果表明,对rAPC表达的条件进行优化后,乳糖诱导rAPC的表达率可达26.8%,与IPTG的诱导结果接近;在高密度培养中,OD600最大达21.8。研究结果可为乳糖替代IPTG大规模生产rAPC奠定基础。     

Accuracy Assessment of the TOPEX/Poseidon Ionosphere Measurements

We conducted an assessment of the TOPEX dual-frequency nadir ionosphere observations in the TOPEX/Poseidon (T/P) GDR by comparing TOPEX with the Center for Orbit Determination in Europe (CODE) Global Ionosphere Map (GIM), the climatological model IRI2001, and the DORIS (onboard T/P) relative ionosphere delays. We investigated the TOPEX (TOPEX Side A and TOPEX Side B altimeters, TSA and TSB, respectively) ionosphere observations for the time period 1995–2001, covering periods of low, intermediate, and high solar activity. Here, we use absolute path delays (at Ku-band frequency of the TOPEX altimeter and with positive signs) rather than Total Electron Content (TEC). We found significant biases between GIM and TOPEX (GIM–TOPEX) nadir ionosphere path delays: ?8.1 ± 0.4 {mm} formal uncertainties and equivalent to 3.7 TECu) and ?9.0 ± 0.7 {mm} (4.1 TECu) for TSA and TSB, respectively, indicating that the TOPEX path delay is longer (or with higher TECu) than GIM. The estimated relative biases vary with latitude and with daytime or nighttime passes. The estimated biases in the path delays (DORIS–TOPEX) are: ?10.9 ± 0.4 {mm} (5.0 TECu) and ?14.8 ± 0.6 {mm} (6.7 TECu), for TSA and TSB, respectively. There is a distinct jump of the DORIS path delays (?3.9 ± 0.7 {mm}, TSA delays longer than TSB delays) at the TSB altimeter switch in February 1999, presumably due to inconsistent DORIS processing. The origin of the bias between GIM (GPS, L-band) and TOPEX (radar altimeter, Ku-band) is currently unknown and warrants further investigation. Finally, the estimated drift rates between GIM and TSA, DORIS and TSA ionosphere path delays for the 6-year study span are ?0.4 mm/yr and ?0.8 mm/yr, respectively, providing a possible error bound for the TOPEX/Poseidon sea level observations during periods of low and intermediate solar activity.     

Pteropods in Southern Ocean ecosystems

To date, little research has been carried out on pelagic gastropod molluscs (pteropods) in Southern Ocean ecosystems. However, recent predictions are that, due to acidification resulting from a business as usual approach to CO₂ emissions (IS92a), Southern Ocean surface waters may begin to become uninhabitable for aragonite shelled thecosome pteropods by 2050. To gain insight into the potential impact that this would have on Southern Ocean ecosystems, we have here synthesized available data on pteropod distributions and densities, assessed current knowledge of pteropod ecology, and highlighted knowledge gaps and directions for future research on this zooplankton group.Six species of pteropod are typical of the Southern Ocean south of the Sub-Tropical Convergence, including the four Thecosomes Limacina helicina antarctica, Limacina retroversa australis, Clio pyramidata, and Clio piatkowskii, and two Gymnosomes Clione limacina antarctica and Spongiobranchaea australis. Limacina retroversa australis dominated pteropod densities north of the Polar Front (PF), averaging 60 ind m⁻³ (max = 800 ind m⁻³) and 11% of total zooplankton at the Prince Edward Islands. South of the PF L. helicina antarctica predominated, averaging 165 ind m⁻³ (max = 2681 ind m⁻³) and up to >35% of total zooplankton at South Georgia, and up to 1397 ind m⁻³ and 63% of total zooplankton in the Ross Sea. Combined pteropods contributed <5% to total zooplankton in the Lazarev Sea, but 15% (max = 93%) to macrozooplankton in the East Antarctic. In addition to regional density distributions we have synthesized data on vertical distributions, seasonal cycles, and inter-annual density variation.Trophically, gymnosome are specialist predators on thecosomes, while thecosomes are considered predominantly herbivorous, capturing food with a mucous web. The ingestion rates of L. retroversa australis are in the upper range for sub-Antarctic mesozooplankton (31.2-4196.9 ng pig ind⁻¹ d⁻¹), while those of L. helicina antarctica and C. pyramidata are in the upper range for all Southern Ocean zooplankton, in the latter species reaching 27,757 ng pig ind⁻¹ d⁻¹ and >40% of community grazing impact. Further research is required to quantify diet selectivity, the effect of phytoplankton composition on growth and reproductive success, and the role of carnivory in thecosomes.Life histories are a significant knowledge gap for Southern Ocean pteropods, a single study having been completed for L. retroversa australis, making population studies a priority for this group. Pteropods appear to be important in biogeochemical cycling, thecosome shells contributing >50% to carbonate flux in the deep ocean south of the PF. Pteropods may also contribute significantly to organic carbon flux through the production of fast sinking faecal pellets and mucous flocs, and rapid sinking of dead animals ballasted by their aragonite shells. Quantification of these contributions requires data on mucous web production rates, egestion rates, assimilation efficiencies, metabolic rates, and faecal pellet morphology for application to sediment trap studies.Based on the available data, pteropods are regionally significant components of the Southern Ocean pelagic ecosystem. However, there is an urgent need for focused research on this group in order to quantify how a decline in pteropod densities may impact on Southern Ocean ecosystems.     

海洋沉积物孔隙水中阴阳离子含量的离子色谱法分析方法

分别采用Metrosep A Supp4-250型阴离子柱和Metrosep C 2-150型阳离子柱,以1.8 mmol/L Na2CO3 1.7 mmol/L NaHCO3和4 mmol/L酒石酸 0.75 mmol/L吡啶二羧酸为阴阳离子淋洗液,用离子色谱仪来测定海洋沉积物孔隙水中阴离子Cl-、Br-和SO42-浓度和阳离子Na 、NH4 、K 、Ca2 、Mg2 的浓度。特别是针对高Cl-和高Na 背景下Br-和NH4 的测定做了专门分析,得到了较理想的结果,建立了一套离子色谱法测定海洋沉积物孔隙水中常见的阴阳离子含量的实验方法。     

Spatial and temporal variations of sedimented organic matter in Xiaohai Lagoon, Hainan Island

The characteristics of grain-size,total organic carbon(TOC) and total nitrogen(TN) contents,TOC/TN ratios,stable carbon isotope(δ13C) and 210 Pb dating were measured in six sediment cores from the Xiaohai Lagoon.The results show distinct spatial and temporal variations in sedimentation patterns.The sediments are dominated by clayey silt,sandy silt and by silty sand in the southern,middle lagoon and the northern lagoon,respectively.TOC and TN contents decline from south to north.Sedimentation rates,determined by 210 Pb dating,tend to decrease from south to middle.However,the determination of sedimentation rate in the north is difficult.These spatial variations are related to the variations in sediment sources and hydrodynamic conditions in the Xiaohai Lagoon.The variations of organic matter signatures can be divided into two stages in the cores from the southern and middle lagoon.Before 1988,the organic matter signatures are relatively stable.The contribution of terrestrial organic carbon sources varies between 60% and 85%.After 1988,the organic matter signatures demonstrate significant variations.TOC and TN contents increase rapidly,TOC/TN ratios decrease,δ13C values shift to higher and the contribution of terrestrial organic carbon sources decreases to 40%-50%.The contributions of phytoplankton organic matter have increased in the sediment since 1988.Increasing aquaculture activities have had a significant impact on organic matter signatures since 1988.The sedimentation rates have increased rapidly in the southern and middle lagoon since 1988 due to the anthropogenic activities which include aquaculture,mining and deforestation.These activities have caused eutrophication and increased siltation in the southern and middle lagoon.     

南海 18°N 断面 上的体积和热盐输运

以2005—2008年4年中南海北部开放航次所获得的水文观测资料为基础,结合卫星高度计遥感资料,采用动力计算方法计算南海18°N断面的经向地转流,并与声学多普勒流速剖面仪(Acoustic Doppler Current Profilers,ADCP)走航观测资料进行对比,进而计算出通过南海18°N断面1000m以浅的各站位以及断面上总的经向地转体积、热、盐输运量。结果表明,2005—2008年南海北部开放航次期间18°N断面上的经向地转流呈相间带状分布,各站位经向地转流流速垂向分布和ADCP观测的大体一致。从卫星高度计获得的海面高度场可知,经向地转流流向的空间变化与海洋中尺度涡旋的活动密切相关。2005—2007年航次期间南海18°N断面上1000m以浅总的经向地转体积、热、盐输运均为南向输运,其3年的平均输运量分别为11.8Sv(1Sv=106m3.s 1)、0.38PW、418.8Gg.s 1;其年际间差别较大,经向地转体积、热、盐输运量均为2005年最大,2006年次之,2007年最小。2008年110°—117°E之间1000m以浅总的海水地转体积、热、盐输运量分别为7.3Sv、0.22PW、259.4Gg.s 1。     

Comparison Study on Wind Input and Whitecapping Dissipation Expressions in Numerical Simulation of Typhoon Generated Waves

In order to investigate the effect of wind input and whitecapping dissipation on the simulation of typhoon-waves, three experiments are conducted with the latest version of SWAN （Simulating WAves Nearshore） model. The three experiments adopt the Komen, Janssens, and Westhuysen expressions for wind input and whitecapping dissipation, respectively. Besides the above-mentioned source tems, other parameterization schemes in these experiments are the same. It shows that the experiment with the Westhuysen expression result in the least simulation errors while that with the Janssens expression has the most. The results from the experiments with Komen and Westhuysen expressions show that the differenees in significant wave height （SWH） have a good correlation with the differences in dissipation energy caused by whiteeapping. This indicates that the whitecapping dissipation source term plays an important role in the resultant differences of the simulated SWH between the two experiments.     

海洋磁力仪性能指标分析与测试

海洋磁力仪性能测试和评价是海洋磁力测量前期技术准备的重要内容,也是当前海洋磁力测量规范要求的薄弱环节。研究了海洋磁力仪的性能指标的具体含义,提出了切合实际的海洋磁力仪性能指标测试内容、流程、方法和要求,采用G-882G SX海洋磁力梯度仪实测数据,计算了海洋磁力仪动态噪声、内符合精度和外符合精度等关键指标,为海洋磁力仪性能测试工作提供了技术指导,也为海洋磁力仪国产化中面临的性能指标论证和设计提供了依据。