小波气候突变的检测--应用范围及应注意的问题

气候突变及其检测是气候变化研究的一个重要方面。气候突变的表现多种多样,目前也有许多检测气候突变的方法,但这些方法能否准确地检测出气候突变现象,他们的适用范围如何,是一个值得注意的问题。研究表明,尽管小波分析方法在检测序列突变方面具有严格的数学意义,但因为其检测到的是序列的均值突变,因此,在应用于气候突变的检测方面应该特别注意,数学上的严格并不等同于气候意义上的严格。因为某些情况下有些突变点并没有一定的气候意义。     

逆方法最优解确定九州近海流速、流量

日本以南海域的调查研究,过去已有不少报道[1~3].众所周知,东海黑潮、西太平洋水和九州沿岸水在九州附近海域交汇,近年来,这里一直是中日黑潮合作调查研究[4]的重点海区之一这些工作显示,日本以南海域的基本特征表现为黑潮路径的大弯曲及其伴生的大冷水团和黑潮两侧中尸度涡的消长过程等等,同时表明确定该海区的流速、流量是探讨以上特征的主要内容之一以往多数作者是采用动力计算方法来确定黑潮相对流速、流量.大家知道,动力计算在不同的参考零面下所得的结果是不同的,这在黑潮强流区表现得尤为明显[5].     

Measurement of stress effects (scope for growth) and contaminant levels in mussels (Mytilus edulis) collected from the Irish Sea

The objective of this research was to quantify the impact of pollution along the coastlines of the Irish Sea. Pollution assessment was based on the combined measurement of scope for growth (SFG), and chemical contaminants in the tissues of mussels (Mytilus edulis) collected from 38 coastal sites around the Irish Sea during June-July in 1996 and 1997. On the UK mainland coast, the SFG showed a general trend with a significant decline in water quality in the Liverpool and Morecambe Bay region. High water quality was recorded along the west coast of Wales, as well as southwest England and northwest Scotland (clean reference sites outside the Irish Sea). Along the coast of Ireland there was a similar trend with reduced SFG within the Irish Sea region. SFG was generally low north of Duncannon and then improved north of Belfast. The poor water quality on both sides of the Irish Sea is consistent with the prevailing hydrodynamics and the spatial distribution of contaminants associated with urban/ industrial development. The decline in SFG of mussels on both sides of the Irish Sea was associated with a general increase in contaminant levels in the mussels. Certain contaminants, including PAHs, TBT, sigmaDDT, Dieldrin, gamma-HCH, PCBs, and a few of the metals (Cd, Se, Ag, Pb), showed elevated concentrations. Many of these contaminants were particularly elevated in the coastal margins of Liverpool Bay, Morecambe Bay and Dublin Bay. A quantitative toxicological interpretation (QTI) of the combined tissue residue chemistry and SFG measurements indicated that at the majority of coastal sites, c. 50 to > 80% of the observed decline in SFG was due to PAHs as a result of fossil fuel combustion and oil spills. TBT levels were highest at major ports and harbours, but these concentrations only made a minor contribution to the overall reduction in SFG. At no sites were individual metals accumulated to concentrations that could cause a significant effect on SFG. The study identified many sites where the observed reduction in SFG was far greater than predicted from the limited number of chemical contaminants analysed, thus indicating the presence of additional 'unknown toxicants'. Sewage (containing domestic, agricultural and industrial components) appears to be an important contributor to reduced SFG and linear alkylbenzenes (LABs) and As may provide suitable 'sewage markers'. There was a highly significant positive correlation between SFG and As (P < 0.001). This relationship may be due to reduced As uptake by algal food material and mussels at sites with elevated P04 concentrations (e.g. at sites with sewage inputs). Phosphate is a known competitive inhibitor of As accumulation, at least in algae. The results highlight that further research is required on 'sewage markers' in mussels. The SFG approach therefore provides a rapid, cost-effective and quantitative measure of pollution impact, as well as a means of identifying the causes through a QTI of tissue contaminants levels. It also serves to identify the presence of unidentified toxicants and areas that require further study.     

滨海海岸侵蚀严重治理海堤刻不容缓

滨海县位于黄河南泛夺淮冲积而成的海滨平原。境内海堤全长54.9公里,海岸线为粉砂土质。黄河北归后,由于大量泥沙来源断绝,在风浪潮流的袭击下,滨海县海岸线严重蚀退,近百年来蚀退17公里,年平均蚀退达150米;同时,滩面每年还以10～15厘米的速度蚀降,近二十年来,滩面高程从海拔1.6米涮降到海拔-1.5米。废黄河口两侧23个村庄已经沦为茫茫大海。解放后,先后挖土2500万方,修筑海堤54.9公里,并先后投资1870万元,兴建五座挡潮闸,10.5公里的海堤干砌块石护坡工     

柔性立管的非线性动力分析

以集中质量法建立了一种能考虑管内流体流动情况下的非线性动力分析方法。将计算结果与前人的工作成果作了比较,并讨论了内流、内压,动态及非线性的影响,得出了一些工程中有用的结论。     

可见光遥感的水面辐射传输模型研究

本文主要讨论水面反射、折射等效应对辐射传输的影响。在考虑水表内反射和水体后向散射的基础上,推导出平静水面下的漫反射率公式。也讨论了起伏水面(由风力作用引起)所产生的太阳和天空光闪烁对可见光水体遥感的影响。     

长期暴露于高压氮氧环境下人体二氧化碳通气反应的变化

本工作研究了36.5米和50米氮氧饱和暴露对人体二氧化碳通气反应的影响。用重复呼吸法测定了两组共13名健康男性受试者的二氧化碳通气反应。氮氧饱和条件下的氧分压维持在0.30绝对压左右,而测定通气反应时的吸入气中的氧分压是0.98绝对压,二氧化碳分压是0.07绝对压,其余为氮气。此外,还测定了受试者的终末潮气二氧化碳分压。实验结果表明:1.二氧化碳通气反应随压力升高而下降。2.二氧化碳通气反应曲线的截距在不同深度均未见有明显的变化。3.在高压条件下,静息状态的终末潮气二氧化碳分压比常压对照值有明显的增加。高压下的二氧化碳通气反应的下降和终末潮气二氧化碳分压的升高,在减压返回海平面后均能恢复到常压水平。高压下的这些变化,可能是呼吸中枢对二氧化碳敏感性的改变所致,也可能是由于呼吸阻力增加引起的呼吸功增加所致,或是两个因素叠加的结果。     

1985年空间海洋学的状况和展望

1984年海洋学工程的主要措施是在空间建立海洋观察站。新的海军遥控海洋测向系统卫星(NROSS)和欧洲空间站的地球资源卫星(ERS—Ⅰ)已得到政府的批准,列入了预算项目,开展了利用卫星调查内容的计划和操作运行的计划。NROSS 的传感器有用于风的 NASA(国家航空和航天局)的传播计量器;用于水面温度,冰的性质和海冰边端的微波无线     

江苏射阳县海滩高产芦苇生产基地建设可行性分析

江苏省射阳县海滩,北起扁担港,南至中路港。射阳河口以北为侵蚀海岸,以南为淤长海岸,滩面广阔,东西宽达10—12公里。全县在平均高潮位线以上海滩面积达42.5万亩,有运粮河、射阳河、黄沙港、新洋港、中路港等河流东流人海;在河流入口处,地势低洼平坦,淡水资源丰富,在港口两岸分     

海洋上层温度结构特征的参数模式

本文根据等(1963,1965)提出的海洋上层温度结构特征的无因次普遍函数,利用1957—1964年暖半年渤、黄、东海159个站次连续站的资料和作者(1983)提出的海面热量平衡的简易计算公式计算海面的热量收支,建立了海洋上均匀层厚度、温跃层强度和跃层下界深度的半经验半理论模式。该模式反映了形成海洋上层温度结构特征的主要因子及其作用,同时避开了一般理论模式中的起算点和目前难以获得的物理海洋学参数,而可以直接利用表面水温、气温和风速进行海洋上层温度特征的计算。