南京夏季城市热岛时空分布特征的观测分析   总被引：6，自引：2，他引：4       下载免费PDF全文

刘寿东  姜润  王成刚  王咏薇 《大气科学学报》2014,37(1):19-27

利用2010年南京夏季城市热岛三维观测试验资料,分析了南京夏季典型天气条件下城市热岛的时空分布特征。结果表明,南京夏季高温晴天日平均热岛强度达1℃以上,夜间热岛强度稳定且强于白天,热岛分布具有方向性特征并与城市土地利用现状对应较好。白天,城市大气混合层的发展速度和高度均大于郊区;夜间,由于城市大气层结的不稳定及下垫面的粗糙特性,致使城市低空始终存在着一个对流混合层,其高度至少有250 m。城市下垫面高热量储存和强湍流输送的共同作用形成边界层内热岛,热岛强度总体上随高度递减,影响高度在白天约900 m、夜间约300 m。  相似文献   

夏季雷州半岛强降水雨滴谱个例分析及降水与闪电相关性统计分析          下载免费PDF全文

张舒婷  牛生杰  林文  张羽  徐峰 《大气科学学报》2014,37(4):476-483

利用2007年8月在雷州半岛观测雷暴获得的雨滴谱和地闪资料,重点分析了8月6日遂溪、湛江一次雷暴云降水个例的雨滴谱特征,对闪电特征与降水的相关性进行了统计分析。结果表明,遂溪站的雨滴谱谱型多为双峰或多峰型,而湛江站的雨滴谱谱型多呈单峰型分布;平均雨滴谱符合Gamma分布;雨强I10mm/h时发生地闪的频率较高,且发生地闪频率随着距测站的距离减少而增加;随着雨强的增大发生正地闪的概率明显增加;降水过程中的闪电频率和距离校准后闪电电流强度的相关性表明,地闪发生的距离越近,频率越高对应雨滴谱谱宽越宽和降水强度越大。  相似文献   

南海大眼金枪鱼和黄鳍金枪鱼生物学特性及其分布   总被引：1，自引：0，他引：1  

冯波  李忠炉  侯刚 《海洋与湖沼》2014,45(4):886-894

利用2010年3月—2013年2月南海金枪鱼延绳钓探捕与渔业生产监测取得的生物学数据和生产数据,对南海的大眼金枪鱼(Thunnus obesus)和黄鳍金枪鱼(Thunnus albacres)的生物学特性和渔场分布进行了研究。结果表明:(1)南海大眼金枪鱼叉长范围50—169cm,平均为111.8cm,体重范围2.45—87kg,平均为33.2kg,叉长(FL)体重(W)关系:W=1.74×10–5FL3.01,性腺成熟度Ⅱ期居多,占总尾数的45.27%。绝对怀卵量109.46—456.95万粒,摄食强度以0—2级为主。大眼金枪鱼延绳钓渔场春夏季分布于南沙西北部和南沙中西部海域;秋冬季分布于西、中沙和南沙西北部海域。渔获水深90%集中在150—400m。(2)南海黄鳍金枪鱼叉长范围41—180cm,平均为107.9cm,体重范围1.2—77.5kg,平均为27.9kg,叉长体重关系:W=2.19×10–5FL2.94,性腺成熟度以Ⅱ—Ⅳ期居多,占总尾数的89.01%,绝对怀卵量15—154万粒,摄食强度以1—2级为主。黄鳍金枪鱼延绳钓渔场春夏季分布于南沙西北部和南沙中西部海域;秋冬季分布于西、中沙、南沙西北部、南沙中西部海域。渔获水深93.75%集中在50—350m。西沙西部和南沙西北部海域是灯光围网和灯光罩网捕捞金枪鱼的重要渔场。研究认为:(1)在南海可发展小型冷海水延绳钓船,在每年10月末—次年5月初在西沙东北海域开展浅水延绳钓作业;(2)在南海的岛礁附近设置PAYAO群,开展金枪鱼灯光罩网或围网捕捞。(3)目前取得的资料仍然有限,未来仍需进一步调查,以掌握南海金枪鱼种群动态,为渔业开发和养护提供建议。  相似文献   

南海温度锋的分布特征及季节变化     

朱凤芹  谢玲玲  成印河 《海洋与湖沼》2014,45(4):695-702

利用50a(1950—2007年)的SODA(Simple Ocean Data Assimilation)数据分析了南海上层温度锋分布特征以及季节变化规律。结果表明:受季风、太阳辐照以及诸多因素影响,温度锋季节变化明显,锋面结构复杂。冬季,温度锋基本沿陆架分布,存在于南海北部海区,从台湾海峡一直延伸到北部湾,发育比较显著;春季,主要出现在南海北部海区、北部湾、越南东部海岸,分布比较广泛;夏季温度锋出现概率增加,出现区域扩大,越南东部出现大面积温度锋;秋季南海中西部海域存在大面积的温度锋。  相似文献   

长江口及其邻近陆架区夏季网采浮游植物及其影响因素   总被引：3，自引：1，他引：2  

江志兵  曾江宁  李宏亮  周锋  陈全震  朱根海  张东声  严小军 《海洋学报》2014,36(6):112-123

2009年6、8月长江口及其邻近陆架区的网采样品中检出浮游植物9门395种(含223种硅藻与125种甲藻)。浮游植物丰度8月(3 077.15×104 cells/m3)显著高于6月(107.80×104 cells/m3)。随长江冲淡水势力增强,位于长江口的丰度高值区8月较6月更偏外侧。种类丰富度8月高于6月,但多样性和均匀度指数略低于6月。6月尖刺伪菱形藻和三角角藻占绝对优势,8月优势种主要有尖刺伪菱形藻、笔尖形根管藻和铁氏束毛藻。骨条藻虽非优势种,但在长江冲淡水区丰度较高。相似性分析和多维尺度分析表明,浮游植物群落组成时空差异显著。典范对应分析表明,温度和盐度是分别影响6、8月群落分布的首要因子。根据水动力和化学参数,该区浮游植物群落分布与环流变化和水团消长密切相关。  相似文献   

北部湾北部生态系统结构与功能研究Ⅱ.浮游动物数量分布及优势种   总被引：2，自引：0，他引：2  

郑白雯  曹文清  林元烧  郑连明  张文静  杨位迪  王宇杰 《海洋学报》2014,36(4):82-90

为了解北部湾北部海区浮游动物数量分布规律及优势种组成,2006—2007年对北部湾进行4个航次的综合性调查。根据浮游动物样品分析结果,研究了北部湾北部浮游动物的丰度、生物量和优势种组成,并利用Spearman等级相关法分析丰度与环境因子间的关系。研究结果表明,北部湾北部浮游动物丰度年均值(183.5±142.9)ind/m3,丰度的季节分布由高到低依次为秋季、夏季、冬季、春季;生物量年均值(139.5±116.8)mg/m3,由高到低依次为春季、秋季、冬季、夏季特征。平面分布上,春、秋两季丰度分布呈远岸高近岸低的趋势,而夏、冬两季则在近岸海域形成高丰度区。生物量的平面分布趋势与丰度的分布趋势基本一致。丰度变化与环境因子的相关性显著,水深、温度及叶绿素a浓度是影响丰度分布的主要因素。肥胖软箭虫Flaccisagitta enflata、亚强次真哲水蚤Subeucalanus subcrassus和间型莹虾Lucifer intermedius在北部湾北部的优势地位显著,优势种演替具有明显的季节性。  相似文献   

基于ROMS模型数值研究南海温跃层的季节变化   总被引：2，自引：0，他引：2  

FAN Wei  SONG Jinbao  LI Shuang 《海洋学报(英文版)》2014,33(7):56-64

On the basis of the regional ocean modeling system （ROMS）, the seasonal variations of the thermocline in the South China Sea （SCS） were numerically investigated. The simulated hydrodynamics are in accordance with previous studies： the circulation pattern in the SCS is cyclonic in winter and anticyclonic in summer, and such a change is mostly driven by the monsoon winds. The errors between the modeled temperature profiles and the observations obtained by cruises are quite small in the upper layers of the ocean, indicating that the ocean status is reasonably simulated. On the basis of the shapes of the vertical temperature profiles, five thermocline types （shallow thermocline, deep thermocline, hybrid thermocline, double thermocline, and multiple thermocline） are defined herein. In winter, when the northeasterly monsoon prevails, most shallow shelf seas in the northwest of the SCS are well mixed, and there is no obvious thermocline. The deep region generally has a deep thermocline, and the hybrid or double thermocline often occurs in the areas near the cold eddy in the south of the SCS. In summer, when the southwesterly monsoon prevails, the shelf sea area with a shallow thermocline greatly expands. The distribution of different thermocline types shows a relationship with ocean bathymetry： from shallow to deep waters, the thermocline types generally change from shallow or hybrid to deep thermocline, and the double or multiple thermocline usually occurs in the steep regions. The seasonal variations of the three major thermocline characteristics （the upper bound depth, thickness, and intensity） are also discussed. Since the SCS is also an area where tropical cyclones frequently occur, the response of thermocline to a typhoon process in a short time scale is also analyzed.  相似文献   

Spatial distribution pattern of seafloor hydrothermal vents to the southeastern Kueishan Tao offshore Taiwan Island   总被引：1，自引：0，他引：1  

HAN Chenhu  YE Ying  PAN Yiwen  QIN Huawei  WU Guanghai  CHEN Chen-Tung Arthur 《海洋学报(英文版)》2014,33(4):37-44

Investigations of the diffusion activities both within and outside the seafloor hydrothermal vents, as well as related mineral genesis, have been one of the key focuses of ocean biogeochemistry studies. Many hydrothermal vents are distributed close to the southern Okinawa Trough on the less-than-30-m deep shallow seafloor off Kueishan Tao, northeast of Taiwan Island. Investigations of temperature, pH and Eh at four depths of hydrothermal plume were carried out near Kueishan Tao at the white(24.83°N, 121.96°E) and yellow(24.83°N, 121.96°E) vents. An 87 h of temperature time series observation-undertaken near the white vent showed that tide is the main factor affecting the background environment. Based on the observed data, 3-dimensional sliced diffusion fields were obtained and analyzed. It was concluded that the plume diffused mainly from north to south due to ebb tide. The yellow vent's plume could effect as far as the white vent surface. From the temperature diffusion field, the vortices of the plume were observed. The Eh negative abnormality was a better indicator to search for hydrothermal plumes and locate hydrothermal vents than high temperature and low pH abnormalities.  相似文献   

The distribution of chlorophyll a and its influencing factors in different regions of the Bering Sea     

KANG Jianhu  CHEN Xingqun  ZHANG Ming 《海洋学报(英文版)》2014,33(6):112-119

The distribution of chlorophyll a(Chl a) and its relationships with physical and chemical parameters in different regions of the Bering Sea were discussed in July 2010. The results showed the seawater column Chl a concentrations were 13.41–553.89 mg/m2 and the average value was 118.15 mg/m2 in the study areas. The horizontal distribution of Chl a varied remarkably from basin to shelf in the Bering Sea. The regional order of Chl a concentrations from low to high was basin, slope, outer shelf, inner shelf, and middle shelf. The vertical distribution of Chl a was grouped mainly from single-peak type in basin, slope, outer shelf, and middle shelf, where the deep Chl a maxima(DCM) layer was observed at 25–50 m, 30–35 m, 36–44 m, and 37–47 m, respectively. The vertical distribution of Chl a mainly had three basic patterns: standard single-peak type, surface maximum type, and bottom maximum type in the inner shelf. The analysis also showed that the transportation of ocean currents may control the distribution of Chl a, and the effects were not simple in the basin of the Bering Sea. There was a positive correlation between Chl a and temperature, but no significant correlation between Chl a and nutrients. The Bering Sea slope was an area deeply influenced by slope current. Silicate was the factor that controlled the distribution of Chl a within parts of the water in the slope. Light intensity was an important environmental factor in controlling seawater column Chl a in the shelf, where Chl a was limited by nitrate rather than phosphate within the upper water. Meanwhile, there was a positive relationship between Chl a and salinity. Algal blooms broke out at Sta. B6 of the southwestern St. Lawrence Island and Stas F6 and F11 in the middle of the Bering Strait.  相似文献   

基于随机集合的非传统型有效波极值模型   总被引：1，自引：0，他引：1  

ZHANG Yi  LAM Jasmine Siu Lee 《海洋学报(英文版)》2014,33(7):125-130

The analysis and design of offshore structures necessitates the consideration of wave loads. Realistic modeling of wave loads is particularly important to ensure reliable performance of these structures. Among the available methods for the modeling of the extreme significant wave height on a statistical basis, the peak over threshold method has attracted most attention. This method employs Poisson process to character- ize time-varying properties in the parameters of an extreme value distribution. In this paper, the peak over threshold method is reviewed and extended to account for subjectivity in the modeling. The freedom in selecting the threshold and the time span to separate extremes from the original time series data is incorpo- rated as imprecision in the model. This leads to an extension from random variables to random sets in the probabilistic model for the extreme significant wave height. The extended model is also applied to different periods of the sampled data to evaluate the significance of the climatic conditions on the uncertainties of the parameters.  相似文献