佛山南海区的教育信息化

聚集社会力量让教育信息化走得更快更远英特尔助力佛山南海区打造数字化教学新模式踏入佛山市南海区旗峰中学的大门,一片清澈的湖面映入眼帘,近旁的凤凰山倒映在平静清澈的湖水里。正值下午三四点间,教室里传来郎朗读书声,而在湖畔、草地、操场甚至校园中的凉亭里,却也时时飘过孩子们的声音,他们或是三五成群、或是独自阅读,手中除了纸质的教材,少不了的还有一台学习本终端,通过它孩子们可以随时随地进入智能课堂、电子图书馆和自习室。这是旗峰中学电子书包项目的重要组成部分,通过云平台的合理搭建、校园网络的高度覆盖、以及教学课件的全面配合,为     

Interannual variability of the chlorophyll-a and sea surface temperature of the Black Sea

A comparative analysis of the Black Sea surface temperature and chlorophyll-a concentration was based on the satellite data (PODAAC JPL AVHRR Pathfinder and SeaWiFS) for 1998–2005. The fields of dispersion and spatial gradient were analysed as well. On the interannual scale, no statistical relationship was found between the field of sea surface temperature and chlorophyll-a. The mesoscale variability (which masked the statistical assessments of interannual coupling) was well pronounced in the fields of both parameters. For the deep part of the sea, a sign of the wave-type origin of the variability of chlorophyll-a and sea surface temperature was evaluated.     

Seasonal evolution of the interannual variability of chlorophyll-a concentration and its forcing factors in the northwestern Pacific from 1998 to 2010

The northwestern Pacific Ocean is a complex region with significant biological spatial variations on a seasonal timescale. To investigate the joint variation patterns on both seasonal and interannual timescales, a season-reliant empirical orthogonal function (S-EOF) analysis was applied to seasonal mean chlorophyll-a concentration (chl-a) anomalies in the northwestern Pacific Ocean during the period 1998–2010. The first two dominant modes accounted for nearly 31% of the total interannual variance, with the second S-EOF mode (S-EOF2) lagging behind the first S-EOF mode (S-EOF1) by one year. S-EOF1 featured a strong variation pattern to the north of 30° N, with maximum chl-a in winter and minimum chl-a in summer. However, S-EOF2 indicated an opposite seasonally evolving pattern compared with S-EOF1, with chl-a increasing along the Kuroshio and extension current from boreal winter to autumn. Both these modes revealed significant relationships with climate-related indices. The two modes corresponded to the central Pacific (CP) La Niña developing episodes and the turnaround from eastern Pacific (EP) La Niña to CP El Niño, respectively. Both modes were associated with the cold phase of the Pacific Decadal Oscillation, which played an important role in prolonging the impact of the El Niño/Southern Oscillation on chl-a seasonal evolution from 1998 to 2010. In addition, we discuss the possible factors dominating chl-a seasonal variation, in terms of the subregions of the northwestern Pacific Ocean. In the subtropical northwestern Pacific Ocean (15° N – 30° N), the chl-a growth was primarily nutrient-limited, whereas in the mid-latitude northwestern Pacific Ocean (35° N – 50° N), the chl-a growth was mainly light-limited.     

Thermal fronts of the southern South China Sea from satellite and in situ data

The major goal of this study was to find match-ups between thermal fronts mapped from satellite sea surface temperature (SST) imagery and from in situ data in the southern South China Sea (SSCS), using 11 ship surveys conducted by the South China Sea Institute of Oceanology (SCSIO) between 1987 and 1999. Fronts were automatically detected by the Cayula–Cornillon multi-image edge detection algorithm (CCA) applied to satellite-derived maps of the Advanced Very High Resolution Radiometer (AVHRR) SST obtained from the Pathfinder project (8364 twice-daily global fields with 9 km resolution between 1985 and 1996). Twice-daily near-instant frontal maps were composited without any averaging or smoothing to produce individual monthly frontal maps covering the period from January 1985 through December 1996 (144 maps in total). Although the SSCS is a tropical sea with little SST difference between water masses, the CCA turned out to be an effective tool for front mapping in the SSCS. Out of the 11 ship surveys analysed in this study, four surveys produced satisfactory match-ups. The percentage of match-ups is considered reasonably high given that (1) ship surveys were not optimized to cross fronts, therefore most in situ sections missed fronts; (2) satellite measurements of SST with AVHRR are hampered by cloudiness, therefore satellite-derived frontal maps might miss some fronts masked by persistent cloudiness. Fronts are more distinct in winter, when cross-frontal SST gradients are enhanced. From oceanographic vertical sections and horizontal maps, fronts are much sharper in the subsurface layer (represented here by 50 m level). Nonetheless, the CCA successfully detected SST fronts with a cross-frontal step as small as 1°C.     

Observation of the Kuroshio intrusion region in the South China Sea from AVHRR data

The variability of sea surface temperature in the region of the Kuroshio intrusion into the South China Sea (SCS) through the Luzon Strait was studied using sea surface temperature (SST) derived from Advanced Very High Resolution Radiometer (AVHRR) from 1985 to 2002. The covariance empirical orthogonal function (CEOF) method was applied for analysing the temporal and spatial variability in the study area. The results show that the Kuroshio intrusion during El Niño periods is weaker than that in La Niña periods. The calculation of surface layer heat of the Kuroshio intrusion region also shows response to the El Niño-La Niña events. The variation is attributed to the changes in wind fields during those events.     

Eddy-feature phytoplankton bloom induced by a tropical cyclone in the South China Sea

This is the first report on an eddy-feature phytoplankton bloom induced by a tropical cyclone (the spiral structure of the bloom was coincident with that of a cold eddy) in the South China Sea (SCS). Applying satellite data, this report can furnish fresh evidence of the relationship between the bloom and the cold eddy. Tropical cyclone Linfa passed over the northern SCS from 16 to 21 June 2009. While it looped over for 2 days (from 17 to 19 June), a cold eddy, which lasted for 11 days in the looping area, was observed on 18 June. Subsequently, an eddy-feature phytoplankton bloom (central location: 18° N, 117.5° E) was detected on 22 June and it remained for 17 days. The character of both the cold eddy and the bloom was rotating counterclockwise, with two arms. High Ekman pumping velocity (>4.5?×?10^?4 m s^?1) was estimated during the passage of Linfa (from 17 to 19 June). The monthly climatology of the mixed layer depth was about 20 m in June, and the maximum Ekman layer depth was about 346 m after Linfa. The analysis indicated that Linfa may have induced the cold eddy, where it looped around. With upwelling and entrainment, the eddy potentially provided nutrients to the bloom in the surface water. The results suggested that the sea surface current changes that Linfa induced had caused the bloom in an eddy feature. Tropical cyclones appear frequently in the SCS, which may affect the activities of mesoscale eddies in this area.     

南海某气田脐带缆设计选择

结合南海某气田水下生产系统的实际情况,介绍脐带缆的功能、液压控制系统的选择、组成结构、管线材质、脐带缆内部管线的尺寸设计等。     

A new regional algorithm for estimating chlorophyll-a in the Alboran Sea (Mediterranean Sea) from MODIS-Aqua satellite imagery

The utility of three different algorithms for retrieving surface chlorophyll-a values from satellite images of MODIS-Aqua is tested in the northern Alboran Sea. The available global algorithm to calculate chlorophyll-a from reflectance of MODIS-Aqua (OC3M) overestimates the surface chlorophyll-a in the study area. Another regional algorithm specifically developed for the Mediterranean Sea (MedOC3) improves the estimates although the best outcome is obtained with OC5, which was developed for Atlantic coastal waters. The three tested algorithms perform worse at in situ chlorophyll-a concentrations higher than 1 mg m^?3 and exhibit uncertainty levels higher than 35% for this range of concentrations. A new algorithm (ALBOC3) is proposed which produces a good estimation of the in situ chlorophyll-a for the whole range of concentrations normally registered in the study area (0.1–3.5 mg m^?3). We hypothesize that the particular bio-optical features of the northern Alboran Sea phytoplankton explain the poor functioning of the published algorithms that have been tested in this work.     

Assessment of SeaWiFS,MODIS, and MERIS ocean colour products in the South China Sea

The Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Medium Resolution Imaging Spectrometer (MERIS) remote-sensing radiometric and chlorophyll-a (chl-a) concentration products for the South China Sea (SCS) from October 2003 to May 2010 were assessed using in situ data. A strict spatiotemporal match-up method was used to minimize the temporal variability effects of atmosphere and seawater around the measurement site. A comparison of the remote-sensing reflectance (R_rs(λ)) of the three sensors with in situ values from the open waters of the SCS showed that the mean absolute percentage difference varied from 13% to 55% in the 412–560 nm spectral range. Generally, the MERIS radiometric products exhibited higher typical uncertainties and bias than the SeaWiFS and MODIS products. The R_rs(443) to R_rs(555/551/560) band ratios of the satellite data were in good agreement with in situ observations for these sensors. The SeaWiFS, MODIS, and MERIS chl-a products overestimated in situ values by 74%, 42%, and 120%, respectively. MODIS retrieval accuracy was better than those of the other sensors, with MERIS performing the worst. When the match-up criteria were relaxed, the assessment results degraded systematically. Therefore, strict spatiotemporal match-up is recommended to minimize the possible influences of small-scale variation in geophysical properties around the measurement site. Coastal and open-sea areas in the SCS should be assessed separately because their biooptical properties are different and the results suggest different atmospheric correction problems.     

Sea surface motion over an anticyclonic eddy on the Oyashio Front

NOAA-6 AVHRR (11-μm band) satellite images for 20 and 21 May 1981 have been used with an interactive computer algorithm to calculate surface flow components from displacement of surface pattern features and elapsed time. The results give estimates of speed and direction for motion along the Oyashio Front and over an anticyclonic eddy between the First and Second Oyashio Intrusions. Speeds of 54 cm/s were detected along the Oyashio thermal ridge. On the periphery of the eddy, speeds in the order of 25 cm/s were present while, nearer the center, motion at 14 cm/s was indicated. A composite picture of flow vectors overlayed on the image for 20 May infers streamline flow characteristics for the surface motion and shows surface isolation of the eddy from the Tohoku area to the south.     

基于GIS的南海动力环境系统的设计与技术实现

利用组件式GIS对南海观测数据进行管理,建立一个可视化、人工交互的客户端平台系统,从而更好地分析和解释南海海洋信息。该系统利用ArcGIS Engine结合.NET平台进行二次开发,采用三层架构,实现了基本GIS图形操作、专题图制作、空间分析、动态跟踪等功能。经测试系统运行良好。     

"数字南海"空间数据仓库构建技术研究

"数字南海"系统是包含五十多种专题数据源,几十种数据格式的软件系统。本文研究从"数字南海"的实际情况出发,提出了"数字南海"空间数据仓库构建策略,对开发的管理系统进行了介绍,并指出了"数字南海"系统研究的下一步工作重点,为系统的实现确定目标,并为数字南海系统的使用以及南海问题的研究理清脉络。     

Internal wave study in the South China Sea using Synthetic Aperture Radar (SAR)

Internal wave distribution maps have been compiled from more than one hundred ERS-1/2, RADARSAT and Space Shuttle SAR images in the South China Sea (SCS) from 1993 to 2000. Based on these distribution maps, most of the internal waves in the north-east part of the SCS were propagating westward. The wave crest can be as long as 200?km with an amplitude of 100?m, due to strong current from the Kuroshio branching out into the SCS. In a recent SCS internal wave study, moorings were deployed in April 1999 and 2000. Simultaneous SAR coverage from ERS-2 and RADARSAT were also collected. The ERS-2 high-resolution SAR images collected from the Taiwan ground station were processed in near real-time to coordinate the field test. SAR data are then used to compare with mooring data. SAR data and Acoustic Doppler Current Profiler (ADCP) data show internal solitons induced by the semi-diurnal tides with a wave speed of 2.4?m?s^?1.     

Sea-level trend in the South China Sea observed from 20 years of along-track satellite altimetric data

The sea-level trend in the South China Sea (SCS) is investigated based on 20 years of along-track data from TOPEX and Jason–1/2 satellite altimetry. The average sea-level rise over all the regions in the study area is observed to have a rate of 5.1 ± 0.8 mm year^?1 for the period from 1993 to 2012. The steric sea level contributes 45% to the observed sea-level trend. These results are consistent with previous studies. In addition, the results demonstrate that the maximum sea-level rise rate of 8.4 mm year^–1 is occurring off the east coast of Vietnam and eastern part of SCS. During 2010–2011, the La Niña event was highly correlated with the dramatic sea-level rise in the SCS; La Niña events were also associated with the maximum rate of sea rise off the east coast of Vietnam, which occurred during 1993 and 2012. We also evaluated the trends in the geophysical (e.g. dynamical atmospheric correction (DAC)) and range corrections (e.g. wet tropospheric correction, dry tropospheric correction, and ionosphere correction), which can leak into the observed sea-level record and be interpreted as part of the sea-level trend. The mean DAC trend within the SCS is found to be 0.4 ± 0.1 mm year^–1 with >0.7 mm year^–1 exhibited in the northern portion of the SCS. This is validated by comparing the altimetric data with the DAC-corrected tide gauge data at Xisha. In the southern SCS, the trend in wet troposphere correction, which is based on radiometer measurements on board the satellite, should be considered for local sea-level trend estimation.     

Three-dimensional oligotrophic ecosystem models driven by physical forcing: the Mediterranean Sea case

An analysis of existing biochemical datasets, collected using different measurements methods, confirms peculiarities of the Mediterranean Sea, such as its oligotrophy, easterly decreasing gradients, and influence of hydrodynamics on the biochemical patterns. Thus assessment of this marine environment requires a model based on a three-dimensional characterization of the ecosystem dynamics. The model, which covers all the Mediterranean basin, conceptually takes into accounts the cycles of nitrogen and phosphorus through the detritus and food chains. It includes as major compartments dissolved inorganic nutrients, two pools of phytoplankton producers, one of zooplankton, and detritus. Dynamic of dissolved oxygen is also simulated. Simulations are presented and results from this conceptualization are reported.     

南海某气区开发工程SIL等级评估研究

结合南海某气区开发工程基本设计项目,介绍采用风险图表法实现安全完整性等级(SIL)评估中相应参数的选择.     

An assessment of chlorophyll-a algorithms available for SeaWiFS in coastal and open areas of the Bay of Bengal and Arabian Sea

Three ocean colour algorithms, OC4v6, Carder and OC5 were tested for retrieving Chlorophyll-a (Chla) in coastal areas of the Bay of Bengal and open ocean areas of the Arabian Sea. Firstly, the algorithms were run using ~ 80 in situ Remote Sensing Reflectance, (R_rs(λ)) data collected from coastal areas during eight cruises from January 2000 to March 2002 and the output was compared to in situ Chla. Secondly, the algorithms were run with ~ 20 SeaWiFS R_rs(λ) and the results were compared with coincident in situ Chla. In both cases, OC5 exhibited the lowest log₁₀-RMS, bias, had a slope close to 1 and this algorithm appears to be the most accurate for both coastal and open ocean areas. Thirdly the error in the algorithms was regressed against Total Suspended Material (TSM) and Coloured Dissolved Organic Material (CDOM) data to assess the co-variance with these parameters. The OC5 error did not co-vary with TSM and CDOM. OC4v6 tended to over-estimate Chla > 2 mg m⁻³ and the error in OC4v6 co-varied with TSM. OC4v6 was more accurate than the Carder algorithm, which over-estimated Chla at concentrations > 1 mg m⁻³ and under-estimated Chla at values < 0.5 mg m⁻³. The error in Carder Chla also co-varied with TSM. The algorithms were inter-compared using > 5500 SeaWiFS R_rs(λ) data from coastal to offshore transects in the Northern Bay of Bengal. There was good agreement between OC4v6 and OC5 in open ocean waters and in coastal areas up to 2 mg m⁻³. There was a strong divergence between Carder and OC5 in open ocean and coastal waters. OC4v6 and Carder tended to over-estimate Chla in coastal areas by a factor of 2 to 3 when TSM > 25 g m⁻³. We strongly recommend the use of OC5 for coastal and open ocean waters of the Bay of Bengal and Arabian Sea. A Chla time series was generated using OC5 from 2000 to 2003, which showed that concentrations at the mouths of the Ganges reach a maxima (~ 5 mg m⁻³) in October and November and were 0.08 mg m⁻³ further offshore increasing to 0.2 mg m⁻³ during December. Similarly in early spring from February to March, Chla was 0.08 to 0.2 mg m⁻³ on the east coast of the Bay.     

Comparison of MERIS,MODIS, SeaWiFS-derived particulate organic carbon,and in situ measurements in the South China Sea

Medium Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) particulate organic carbon (POC) concentration products for the South China Sea (SCS) were compared with in situ data collected from October 2007 to December 2013. Spectral remote-sensing reflectance (R_rs,λ) was also measured to help understand POC algorithm performance. A strict comparison of the satellite-derived POC and in situ measurements showed that MERIS, MODIS, and SeaWiFS underestimated in situ values by 29.1, 11.7, and 31.5%, respectively. Similar results were obtained with a relaxed matching criterion. Through analysis of the causes of product uncertainty, the results suggested that satellite retrieval of R_rs,λ and the global POC algorithm both have an impact on inversion accuracy. However, the formulation of the POC algorithm seems to be more critical. When a regional algorithm was developed to obtain satellite-derived POC, both the strict and relaxed comparison results showed significant improvement, but for coastal waters, both algorithms had larger errors. Other factors affecting the comparison are also discussed.     

Seasonal and spatial distribution of chlorophyll-a concentrations and water conditions in the Gulf of Tonkin, South China Sea

The Gulf of Tonkin is a semi-closed gulf northwest of the South China Sea, experiencing reversal seasonal monsoon. Previous studies of water conditions have been conducted in the western waters of the gulf, but very few studies of the Chlorophyll-a (Chl-a) distribution have been carried out for the entire gulf. The present study investigates seasonal and spatial distributions of Chl-a and water conditions in the Gulf of Tonkin by analyzing Sea-viewing Wide Field-of-View Scanner (SeaWiFS) derived Chlorophyll-a (Chl-a), in situ measurements, sea surface temperatures (SST), and other oceanographic data obtained in 1999 and 2000. The results show seasonality of Chl-a and SST variations in the Gulf of Tonkin, and reveal phytoplankton blooming events in the center part of the gulf during the northeast monsoon season. In summer, Chl-a concentrations were relatively low (<0.3 mg m⁻³) and distributed uniformly throughout most of the area, with a belt of higher Chl-a concentrations along the coast, particularly the coast of Qiongzhou Peninsula; in winter, Chl-a concentration increased (0.5 mg m⁻³) in the entire gulf, and phytoplankton blooms offshore-ward from the northeast coast to the center of the gulf, while Chl-a concentrations reached high levels (0.8-1 mg m⁻³) in the center of the blooms. One peak of Chl-a concentrations was observed during the northeast monsoon season in the year. SST were high (27-29 °C) and distributed uniformly in summer, but lower with a large gradient from northeast (17 °C) to southwest (25 °C) in winter, while strong northeast winds (8-10 m/s) were parallel to the east coast of the gulf. Comparison of Chl-a values shows that SeaWiFS derived Chl-a concentrations match well with in situ measurements in most parts of the gulf in May 1999, but SeaWiFS derived Chl-a are higher than in situ data in river mouth waters. The seasonal variation of Chl-a concentrations and SST distribution were associated with the seasonally reversing monsoon; the winter phytoplankton blooms were related to vertical mixing and upwelling nutrients drawn by the northeast wind.