Origin and three-dimensional fluorescence spectrum of the chromophoric dissolved organic matter in Yangtze estuary, East China

Dissolved organic matter （DOM） is an important chemical component in natural water. Chromophoric dissolved organic matter （CDOM）, a fraction of optical properties, plays art important role in the biogeochemical cycle of nutrients in aquatic environment. People realized that DOM cycle is crucial in the global carbon and nitrogen flux, and also is inherently related to nutrients and trace metal elements. Therefore, CDOM was concerned by scientists in global oceanography and limnology fields. Water samples were collected from three sections （North Channel, South Channel and Zhuyuan） of the Yangtze （Changjiang River） estuary in March 2006 Three-dimensional excitation emission matrix （3-DEEM） fluorescence spectra were analyzed for those filtrates through Whatman GF/F filters. Dissolved organic carbon （DOC） was also measured by TOC analyzer. The tidal variety was also taken into account. The 3-D EEM fluorescence scans suggested the fluorescence characteristics of humic acid （Ex=332-344 nm, Em=439-451 nm） and fulvic acid （Ex=250-254 nm, Em=472-478 nm） were obvious, and the fluorescence group of protein-like and tyrosine （Ex=230 nm, Em=283 nm） was also found. They are mainly composed of CDOM in the Yangtze estuary. Further data analysis, especially the fluorescence index （f 450/500）, showed that terrestrial signal was rather strong （1.41-1.65） in the surface water, however, some terrestrial CDOM signals of bottom water showed excursions （1.28-1.39）. On the other hand, anthropogenic sign was impressed in the waters of Zhuyuan, which is one of the main drain outlets of Shanghai Metropolis. DOC concentrations ranged from 2.2 mg/L to 3.4 mg/L in Zhuyuan and South Channel, and from 2.0 mg/L to 2.4 mg/L in North Channel. The tide effect played a role in the composition of the CDOM measured by 3-D fluorescence scan technology.     

Water chemical behavior at Yangtze （Changjiang） River estuary

Geochemical cycling has received wide attention due to the need to understand the pathways of pollutants through our present environment. In this regard the Yangtze River plays a significant role in putting those pollutants into the East China SeafWorld Oceans. The Yangtze River is of high sedimentation rate and water discharge. The watershed covers variable climate regions from temperate to subtropical and from semiarid to humid. Twenty three （23） sampling locations at the estuary have been selected for understanding the dynamic relationships. The elements （Cl^-, SO4^2-, Na^＋, K^＋, and Ca^2＋） show conservative behavior during mixing of fresh water with saline water whereas Mg^2＋, Mn^2＋ show a non-conservative pattern . The relationships between Na^＋/SO4^2- and Cl^-/SO4^2- molar ratios show a mixing of more than two water sources.     

长江中下游夏季高温灾害机理及预测

利用我国1961-2003年夏季（6—8月）高温资料，建立长江中下游地区主要城市强高温及高温过程较完整的时间序列，探讨了该地区主要城市高温气候特征。分析该地区南京、杭州、南昌等城市夏季高温灾害机理，东亚副热带高压是造成长江中下游地区城市夏季高温的主要影响系统。在此基础上用均生函数-最佳子回归集构造预测模型，预测夏季月高温出现日数，通过42a高温资料预报检验，有较好的预测效果，值得在业务中应用。     

冬季浙闽沿岸水分布的短期变动与风的关系初探

利用1999年7月至2003年5月期间的遥感数据,包括AVHRR海表层温度、QuikSCAT风场和风应力数据,在分析4年内月平均遥感温度场和风场特征与历年现场观测所获得的认识一致的基础上,选取2002年002-008天这一连续晴空的时段,尝试建立简单的沿岸冷水影响面积表征方法,初步探讨了冬季台湾海峡浙闽沿岸水分布的短期变动与风应力之间的关系。结果表明,风是决定冬季台湾海峡海表层温度逐日变动的关键因素,日平均SST与风应力的相关系数R2达到0·90。采用温度法(SST≤17℃)和温度空间距平法(≤-1℃)表征的浙闽沿岸水影响面积的变化趋势基本一致,而且影响面积的逐日变动与风应力显著相关,二者的相关系数R2分别达到0·90和0·91。     

用自然正交展开法分析长江中下游降水的季节变化

利用自然正交展开（EOF）方法探讨了气象要素场的季节变化特征。结果发现：应用自然正交展开方法分析某一气象要素场的季节变化或年际变化时，要针对不同问题，对原始资料场进行不同处理，使之与分析对象相匹配；只有这样，自然正交展开的特征向量才具有明确的物理意义。在该文中使用自然正交展开方法分析了长江中下游及全国降水的季节变化特征。     

冰后期长江三角洲沉积通量的初步研究

在265个长江三角洲钻孔地层资料中识别出了冰后期海侵旋回底界面和(或)最大海侵面, 分别记录了它们的埋深值. 由此绘制出了长江三角洲冰后期沉积物等厚图及冰后期最大海侵以来的沉积物等厚图, 计算了冰后期沉积旋回及其海侵和海退层序的沉积物数量, 并且分析了其分布特征. 结果表明, 长江三角洲在冰后期及其海侵和海退期间的沉积物数量分别为17742.2×10⁸ , 9791.9×10⁸和7950.3×10⁸ t. 其中, 下切河谷沉积量超过三角洲两翼, 海侵期沉积量大于海退期, 南翼沉积量大于北翼, 两翼前缘沉积量大于后缘. 综合考虑冰后期滞留于现今三角洲地区的沉积物数量与长江输沙量之间比值的变化以及输沙量本身可能的变化, 可以认为冰后期长江年均输沙量应当在2.36×108~4.86×10⁸ t之间, 总量约为35400×10⁸~70800×10⁸ t; 年均输向外海和相邻岸段的泥沙在1.18×10⁸~3.54×10⁸ t之间, 总量约为17700×10⁸~53100×10⁸ t.     

黄海及其沿岸历史地震初步研究

黄海及其边缘，经历史地震资料整理，地震参数估定与编目，截至1949年8月，共有M≥3级地震2187次，其中M≥43/4级地震259次，资料显示大致有三个相对集中活跃区，16世纪曾有过历史地震活动高潮。     

长江巨洪前期物理因子的配置

提出了长江巨洪前期物理因子配置的概念，在每一次巨洪发生之前，影响巨洪的主要物理因子之间一般都会表现出相似的特征，即出现一些固有的配置，这些配置正是长江发生巨洪的强信号，对长江巨洪的预测研究具有重要的指示作用。     

长江中下游岸线资源的特征及其开发利用

运用大比例尺水下地形图，在岸线资源总量勘查的基础上，评价了长江中下游干流岸线的水深条件、岸线稳定性条件和建港自然条件，分析了本区域岸线资源的基本特征，提出了长江岸线资源开发的基本原则和中下游干流岸线利用建议。