基于高度计遥感数据的北太平洋中尺度涡提取

针对海洋中尺度涡现象,提出一种基于海平面高度异常数据(SLA)的中尺度涡泛克里金提取算法。该算法运用变差函数工具计算SLA变差场,定义为广义振幅场,再利用泛克里金插值消除数据虚警和噪声,借助广义振幅场与实际振幅的关系通过少数几条特征等值线实现涡旋及其属性的提取。选取北太平洋作为实验区,采用2012年4月的4期SLA进行了中尺度涡的定量提取、分析,共提取出841个中尺度涡(含3个多核涡),包含450个气旋涡和391个反气旋涡;与其他遥感提取方法的对比显示北太平洋中尺度涡的成功检测率接近90%,过度检测率小于20%。结果表明:(1)算法具有省时高效性,通过对SLA场的重构创建广义振幅场,避免了等值线筛选过程,相对于海面高度闭合等值线等其他遥感方法具有判据简单及提取速度快的特性;(2)可靠性好,能够通过推导得出的特征等值线确保稳定的提取准确度;算法建立在发展成熟的等值线提取方法之上,并且有变差函数与泛克里金法的理论支撑;(3)自适应性强,可以对任意海区进行实时的涡旋检测和提取,并且除振幅值统计资料及必要基础数据外无需依赖其他辅助性数据。     

Geochemical speciation and spatial distributions of phosphorus in surface sediments from the basin of the Marcus-Wake seamounts in the western Pacific Ocean

The concentrations of five forms of phosphorus(P) including exchangeable or loosely adsorbed P(Ex-P), Febound P(Fe-P), authigenic P(Auth-P), detrital P(Det-P), and organic P(Org-P) from the basin among the Marcus-Wake seamounts(19.4°–24°N, 156.5°–161.5°E) in the western Pacific Ocean were quantified using a sequential extraction method(SEDEX) to investigate the distribution and sources of different P species.Concentrations of total P(TP) varied from 14.0 μmol/g to 44.1 μmol/g, with an average of...     

三江源地区春夏季降水与太平洋海温的关系

从预测三江源地区春季、夏季降水趋势的需要出发,利用聚类分析法将三江源地区春、夏季降水场分为3个区域。通过对3个区春、夏季降水指数与前期太平洋海温相关普查,定义了与3个区春、夏季降水指数相关的海温分布型指数。冬季西太平洋海温偏低(偏高),赤道中、东部太平洋海温偏高(偏低)的海温分布型造成三江源1区、3区春季降水减少(增加);冬季赤道太平洋中部、加利福尼亚海域海温偏高(偏低)的海温分布型造成2区、3区夏季降水减少(增加)。对冬季太平洋海温分布型与后期春、夏季500 hPa北半球高度场的相关分析结果表明:当冬季西太平洋海温综合指数高(低)时,春季高度场印度高压、中西伯利亚槽及阿留申低槽加强(减弱),三江源地区春季降水偏少(偏多);而当冬季太平洋中部、加利福尼亚海域海温综合指数高(低)时,夏季高度场伊朗高压、中西伯利亚高脊加强(减弱)及西太平洋副高位置偏南(偏北),夏季降水偏少(偏多)。     

Marine debris collects within the North Pacific Subtropical Convergence Zone

Floating marine debris, particularly derelict fishing gear, is a hazard to fish, marine mammals, turtles, sea birds, coral reefs, and even human activities. To ameliorate the economic and environmental impact of marine debris, we need to efficiently locate and retrieve dangerous debris at sea. Guided by satellite-derived information, we made four flights north of Hawaii in March and April 2005. During these aerial surveys, we observed over 1800 individual pieces of debris, including 122 derelict fishing nets. The largest debris concentrations were found just north of the North Pacific Transition Zone Chlorophyll Front (TZCF) within the North Pacific Subtropical Convergence Zone (STCZ). Debris densities were significantly correlated with sea-surface temperature (SST), chlorophyll-a concentration (Chla), and the gradient of Chla. A Debris Estimated Likelihood Index (DELI) was developed to predict where high concentrations of debris would be most likely in the North Pacific during spring and early summer.     

Diagnosing SST Error Growth during ENSO Developing Phase in the BCC_CSM1.1(m) Prediction System

In this study, the predictability of the El Nino-South Oscillation(ENSO) in an operational prediction model from the perspective of initial errors is diagnosed using the seasonal hindcasts of the Beijing Climate Center System Model,BCC;SM1.1(m). Forecast skills during the different ENSO phases are analyzed and it is shown that the ENSO forecasts appear to be more challenging during the developing phase, compared to the decay phase. During ENSO development, the SST prediction errors are significantly negative and cover a large area in the central and eastern tropical Pacific, thus limiting the model skill in predicting the intensity of El Nino. The large-scale SST errors, at their early stage, are generated gradually in terms of negative anomalies in the subsurface ocean temperature over the central-western equatorial Pacific,featuring an error evolutionary process similar to that of El Nino decay and the transition to the La Nina growth phase.Meanwhile, for short lead-time ENSO predictions, the initial wind errors begin to play an increasing role, particularly in linking with the subsurface heat content errors in the central-western Pacific. By comparing the multiple samples of initial fields in the model, it is clearly found that poor SST predictions of the Nino-3.4 region are largely due to contributions of the initial errors in certain specific locations in the tropical Pacific. This demonstrates that those sensitive areas for initial fields in ENSO prediction are fairly consistent in both previous ideal experiments and our operational predictions,indicating the need for targeted observations to further improve operational forecasts of ENSO.     

与印度洋偶极子模态有关的西太平洋海温异常型及其对东亚冬季气候的影响

利用NOAA（National Oceanic and Atmospheric Administration）海温、GPCP（Global Precipitation Climatology Project）降水和ERA-20C（ECMWF's first atmospheric reanalysis of the 20th century）再分析大气环流资料,结合大气环流模式ECHAM5敏感性试验,研究了与秋季印度洋海温偶极子模态（IOD）相联系的冬季热带西太平洋海温异常型及其对东亚冬季气候的影响。发现在秋季发生IOD背景下,冬季西太平洋存在两类海温异常的变化型:一类是西太平洋区域一致偏暖/冷的模态,另一类是区域西冷东暖/西暖东冷的模态。尽管西太平洋海温一致偏暖和西冷东暖这两类海温变化型均有利于华南冬季少降水,但影响的范围有所不同。一致偏暖型引起的少降水范围较大,从华南扩展到长江中下游地区。西冷东暖型引起少降水范围主要限于华南,而在长江中下游到华北则降水偏多。相应地,在大气环流上,尽管两类海温异常型均有利于在西北太平洋菲律宾海附近出现气旋式环流异常,但气旋的强度和中心位置有差异。一致偏暖型引起的气旋偏强,中心位置偏西,其后部异常东北风控制的范围更大,导致少降水范围更大,而西冷东暖型引起的气旋偏弱,中心位置偏东,其后部异常东北风控制的范围小,导致少降水区域主要在华南沿海。本文结果对认识IOD调制随后冬季东亚降水异常的机理有重要意义。     

空间太阳望远镜数据总线解决方案

空间太阳望远镜的星上数据处理系统需要对高速、海量的科学数据流进行实时处理,选择合适的空间数据总线解决方案至关重要.SpaceWire是由欧空局提出的一种新型高速串行数据总线标准,已经应用并计划用于ESA和NASA等多个任务中.在空间太阳望远镜项目中,Spacewire将负责在五个载荷仪器和科学处理单元(SDPU)之间组建网络,完成高速数据传输的任务.通过对SpaceWire协议进行分析,设计了基于SpaceWire的双冗余总线的容错方案.建立了基于DSP+FPGA结构的通信测试平台,并分别给出软硬件设计及测试结果.     

ENSO amplitude change in observation and coupled models

Observations show that the tropical E1 Nifio-Southern Oscillation （ENSO） variability, after removing both the long term trend and decadal change of the background climate, has been enhanced by as much as 60% during the past 50 years. This shift in ENSO amplitude can be related to mean state changes in global climate. Past global warming has caused a weakening of the Walker circulation over the equatorial Indo-Pacific oceans, as well as a weakening of the trade winds and a reduction in the equatorial upwelling. These changes in tropical climatology play as stabilizing factors of the tropical coupling system. However, the shallower and strengthening thermocline in the equatorial Pacific increases the SST sensitivity to thermocline and wind stress variabilities and tend to destabilize the tropical coupling system. Observations suggest that the destabilizing factors, such as the strengthening thermocline, may have overwhelmed the stabilizing effects of the atmosphere, and played a deterministic role in the enhanced ENSO variability, at least during the past half century. This is different from the recent assessment of IPCC-AR4 coupled models.     

A Study of the Teleconnections in the Asian-Pacific Monsoon Region

The interactions among the Asian-Pacific monsoon subsystems have significant impacts on the climatic regimes in the monsoon region and even the whole world. Based on the domestic and foreign related research, an analysis is made of four different teleconnection modes found in the Asian-Pacific monsoon region, which reveal clearly the interactions among the Indian summer monsoon （ISM）, the East Asian summer monsoon （EASM）, and the western North Pacific summer monsoon （WNPSM）. The results show that： （1） In the period of the Asian monsoon onset, the date of ISM onset is two weeks earlier than the beginning of the Meiyu over the Yangtze River Basin, and a teleconnection mode is set up from the southwestern India via the Bay of Bengal （BOB） to the Yangtze River Basin and southern Japan, i.e., the ＂southern＂ teleconnection of the Asian summer monsoon. （2） In the Asian monsoon culmination period, the precipitation of the Yangtze River Basin is influenced significantly by the WNPSM through their teleconnection relationship, and is negatively related to the WNPSM rainfall, that is, when the WNPSM is weaker than normal, the precipitation of the Yangtze River Basin is more than normal. （3） In contrast to the rainfall over the Yangtze River Basin, the precipitation of northern China （from the 4th pentad of July to the 3rd pentad of August） is positively related to the WNPSM. When the WNPSM is stronger than normal, the position of the western Pacific subtropical high （WPSH） becomes farther northeast than normal, the anomalous northeastward water vapor transport along the southwestern flank of WPSH is converged over northern China, providing adequate moisture for more rainfalls than normal there. （4） The summer rainfall in northern China has also a positive correlation with the ISM. During the peak period of ISM, a teleconnection pattern is formed from Northwest India via the Tibetan Plateau to northern China, i.e., the ＂northern＂ teleconnection of the Asian summer monsoon. The     

中国东部—西太平洋副热带季风和降水的气候特征及成因分析

利用1981—2000年候平均NCEP/NCAR再分析资料和CMAP全球降水资料,分析了从中国东部大陆到西太平洋副热带地区季风和降水季节变化的特征及其与热带季风降水的关系,探讨了季风建立和加强的原因。夏季东亚—西太平洋盛行的西南风开始于江南和西太平洋副热带的春初,并向北扩展到中纬度,热带西南风范围向北扩展的迹象不明显。从冬到夏,中国西部和西太平洋副热带的表面加热季节变化可以使副热带对流层向西的温度梯度反转比热带早,使西南季风在副热带最早开始;从大气环流看,青藏高原东侧低压槽的加强和向东延伸,以及西太平洋副热带高压的加强和向西移动,都影响着副热带西南季风的开始和发展;初夏江南的南风向北扩展与副热带高压向北移动有关,随着高原东侧低压槽向南延伸,槽前的偏南风范围向南扩展。随着副热带季风建立和向北扩展,其最大风速中心前方的低层空气质量辐合和水汽辐合以及上升运动也加强和向北移动,导致降水加强和雨带向北移动。热带季风雨季开始晚,主要维持在热带而没有明显进入副热带,江淮梅雨不是由热带季风雨带直接向北移动而致,而是由春季江南雨带北移而致。在热带季风爆发前,副热带季风区水汽输送主要来自中南半岛北部和中国华南沿海,而在热带季风爆发后,水汽输送来自孟加拉湾和热带西太平洋。