Dynamic Performance Investigation of A Spar-Type Floating Wind Turbine Under Different Sea Conditions

Both numerical calculation and model test are important techniques to study and forecast the dynamic responses of the floating offshore wind turbine (FOWT). However, both the methods have their own limitations at present. In this study, the dynamic responses of a 5 MW OC3 spar-type floating wind turbine designed for a water depth of 200 m are numerically investigated and validated by a 1:50 scaled model test. Moreover, the discrepancies between the numerical calculations and model tests are obtained and discussed. According to the discussions, it is found that the surge and pitch are coupled with the mooring tensions, but the heave is independent of them. Surge and pitch are mainly induced by wave under wind wave conditions. Wind and current will induce the low-frequency average responses, while wave will induce the fluctuation ranges of the responses. In addition, wave will induce the wavefrequency responses but wind and current will restrain the ranges of the responses.     

白令海大型底栖动物群落结构及其空间分布格局

Due to its unique geological location, the Bering Sea is an ideal place to investigate the water exchange and ecosystem connectivity of the Pacific Ocean–Arctic Ocean and subarctic–Arctic region. Based on a number of summer surveys(July to September, 2010, 2012 and 2014), macrobenthic communities and their spatial-temporal patterns are exhibited for the majority of the Bering Sea(53°59′–64°36′N). The results show that the macrobenthic communities were dominated by northern cold-water species and immigrant eurythermic species, and the communities assumed a dispersed and patchy distribution pattern. Polychaetes(Scoloplos armiger), crustaceans(Ceradocus capensis) and sea urchins(Echinarachnius parma) were the main dominant groups in the shallow shelves; the sea star(Ctenodiscus crispatus) and the brittle star(Ophiura sarsii) were the main dominant groups in the continental slope; whereas small polychaetes(Prionospio malmgreni) dominated the basin area. Sediment type, water depth, and currents were the major factors affecting the structure and spatial distribution of the macrobenthic communities. Compared with other seas, the shallow areas of the Bering Sea showed an extremely high-standing biomass. In particular, the northern shelf area(north of St. Lawrence Islands and west of 170°W),which is primarily controlled by Anadyr Water, is an undersea oasis. In contrast, a deficiency in the downward transport of particulate organic carbon has resulted in a desert-like seabed in the basin area. By comparing our results to previous studies, we found that macrobenthic communities of the Bering Sea have undergone significant structural changes in recent decades, resulting in a decrease in abundance and an increase in biomass.In addition, populations of amphipods and bivalves in the northern shelves have decreased significantly and have been gradually replaced by other species. These changes might be associated with advanced seasonal ice melting,changes in organic carbon input, and global warming, indicating that large-scale ecosystem changes have been occurring in the Bering Sea.     

南海北部底层沉积物捕获器中海雪和生物粪粒组成及来源探究

Sediment traps are an important tool for studying the source, composition and sedimentation processes of sinking particulate matter in the ocean. An in situ observational mooring(TJ-A-1) is located in the northern South China Sea(20.05°N, 117.42°E) at a water depth of 2 100 m and equipped with two sediment traps deployed at 500 m and 1 950 m. Samples were collected at 18-day intervals, and 20 samples were obtained at both depths from May 2014 to May 2015. Large amounts of fecal matter and marine snow were collected in the lower trap. The fluxes of marine snow and fecal pellets exhibited a fluctuating decrease between May 2014 and early August 2014 and then stabilized at a relatively low level. Scanning electron microscopy observations revealed that the main components of the marine snow and fecal pellets were diatoms, coccolithophores, radiolarians, and other debris, all of which are planktons mostly produced in photic zone. Used in conjunction with the particle collection range estimates from the lower trap and data on ocean surface chlorophyll, these marine snow and fecal pellets were related to the lateral transport of deep water and not vertical migrations from overlying water column. Moreover, the source area might be southwest of Taiwan.     

荒漠绿洲湿地土壤水热盐动态过程及其影响机制

以甘肃临泽荒漠绿洲湿地为研究对象，通过对土壤温度、含水量、电导率及蒸散量的野外观测，在植物生长期和冻融期分别深入分析水热盐耦合运移过程及其影响因素，探讨水热梯度对盐分运移及其分布格局的控制作用。结果表明：土壤温度整体呈现出春夏季逐渐升高、秋冬季降低趋势。在冻结期，土壤表现为脱盐状态，表层电导率由2.8 mS·cm^-1降到1.2 mS·cm^-1；而在消融期为积盐状态，表层电导率由1.2 mS·cm^-1升到3.7 mS·cm^-1。在生长期，土壤含水量和电导率波动较为剧烈，表层含水量27%~43%，表层电导率3~5.5 mS·cm^-1，土壤脱盐、积盐反复出现。全年蒸散量总体呈单峰变化趋势，年蒸散量507 mm；土壤电导率与蒸散量呈正比关系，与地下水位呈负相关关系；蒸散发作用是土壤表层积盐的主要驱动力，而地下水波动影响着湿地脱盐、洗盐过程。因此，荒漠绿洲湿地土壤盐分累积过程是水分运移和热量传输过程发生变化的结果。     

移动测量系统宽幅影像的几何拼接与量测

研究了移动测量系统宽幅影像的拼接与量测算法。通过建立三幅影像柱面全景投影的几何关系,能够直接拼接完成宽幅影像。利用宽幅影像和原始影像间反投影变换关系以及三幅原始影像的同、异步立体像对,可建立宽幅影像与物方空间坐标间一一对应关系,从而实现宽幅影像目标的量测算法。宽幅影像的投影拼接和量测实验表明,利用柱面全景投影拼接得到宽幅影像的方法可应用于移动测量平台宽幅影像序列的拼接;在原始影像具备同步立体像对的条件下,宽幅影像量测的绝对精度可达1 m以内,相对精度可达0.2 m以内,满足城市环境实景目标量测的精度需求。     

祁连山北缘深部弧形褶皱—逆冲带及其油气勘探前景

祁连山北缘-河西走廊西段位于青藏高原东北缘,是新生代陆内构造活动最强烈地区。基于野外构造观测、横跨山前及前陆盆地区的三维地震构造分析与解释,结合地震地质属性提取分析,识别出祁连山北缘-酒泉盆地西段窟窿山-柳沟庄带隐伏的弧形褶皱-逆冲带,该弧形构造是造山带基底逆冲构造楔体垂向差异抬升与向前陆方向差异运动的产物;该弧形结构控制本区下白垩统地层裂缝发育、分布与破裂强度,并与本区先期断裂、裂缝带产生构造叠加效应,形成弧形构造“中央强裂缝发育带”,是形成构造裂缝型油气藏的有利区域。     

基于FY3A/MERSI资料分析广东省气溶胶光学厚度分布

利用国产极轨气象卫星FY3A的MERSI AOD产品分析2010—2013年广东省气溶胶光学厚度的分布规律。结果表明:MERSI AOD产品与地面太阳光度计实测数据的相关系数为0.72,其平均绝对值误差为0.12,均方根误差为0.15,数据精度可满足研究需要;从AOD的空间分布看,珠三角西翼东翼山区五市,其中佛山市、东莞市、中山市为广东省AOD均值最高的地区,梅州市、河源市为广东省AOD均值最低的地区;从AOD的时间分布看,2010—2013年间,AOD呈现先升高后降低的趋势,2011年为拐点,与此同时,AOD还表现出明显的季节变化特征,春季为AOD高值期,夏季、秋季次之,冬季最低。     

气候变化情景下黄淮海区域热量资源及夏玉米温度适宜度

利用黄淮海区域90个站点1971—2000年逐日气象资料以及国家气候中心发布的未来气候变化情景(A1B)下区域气候模式(Reg CM3)模拟的黄淮海区域1951—2070年0.25°×0.25°格点气象资料,结合夏玉米主要生育期对温度的需求,构建了黄淮海区域的温度适宜度和变异系数模型,并对1951—2070年黄淮海区域热量资源、夏玉米主要生育期的温度适宜度及其变异系数的时空变化特征进行分析。结果表明:1)黄淮海区域≥10℃积温和80%保证率下日平均温度≥10℃的初日均呈现由北向南依次增加的趋势,且随时间推移,分别呈增加和提前趋势。2)黄淮海区域夏玉米播种—出苗期的温度适宜度随时间整体呈逐渐上升的变化趋势、其变异系数随时间呈降—升—降的变化趋势;出苗—抽雄期的温度适宜度随时间呈先降后升的变化趋势、其变异系数呈降—升—降—升的变化趋势;抽雄—成熟期的温度适宜度空间上呈现2010年前北低南高、未来情景下中部低四周高的分布趋势,时间上呈2010年前稳定、未来情景下先降后升的变化趋势,其变异系数呈相反变化趋势;3)黄淮海区域夏玉米温度适宜度及其变异系数从播种—出苗期—出苗—抽雄期—抽雄—成熟期均呈反相位的变化关系。