基于实测与模拟的青海湖冰厚时空变化特征

湖冰厚度是湖泊在封冻期的重要物理参数,明晰其时空变化特征对于认识气候变暖背景下的湖冰响应规律具有重要的理论价值和现实意义.基于ERA5 Climate Reanalysis气温数据集、MODIS MOD09GQ数据产品和2019年湖冰钻孔测厚数据及雷达测厚数据,重建20002019年青海湖冰厚时间序列并分析其时空变化特...     

保安湖鳜鱼卵巢的周年变化

对保安湖性成熟雌性鳜鱼卵巢进行了组织和组织化学研究。鳜鱼卵母细胞发育分为５个时相。退化卵终年存在,区分为产产萎缩和产后退化吸收。鳜鱼的繁殖期在４月底至６月底。一个生殖周期中,卵巢两次达到成熟,为分批主卵类型。鳜鱼卵黄物质有三种形式,液泡含在量多糖物质。     

巢湖四条入湖河流硝态氮污染来源的氮稳定同位素解析

采用氮稳定同位素技术对巢湖四条主要污染输入河流(南淝河、十五里河、派河和双桥河)的氮污染状况和硝态氮来源进行研究.结果表明,巢湖四条入湖河流氮污染最严重的是十五里河,其次是南淝河和派河,双桥河的污染相对较轻.硝态氮的稳定同位素分析结果表明,巢湖四条入湖河流的硝态氮污染物在季节上受到不同因子的影响.十五里河和南淝河的硝态氮污染主要来源于城市生活污水和工业废水;派河的硝态氮污染在冬季主要来源于工业废水,春季来源于农业面源,而在夏季主要受到雨水的影响;双桥河的硝态氮污染冬、春季主要来源于农业面源,夏季主要受雨水的影响.此外本研究结果还表明巢湖四条主要入湖河流的氮污染源主要为铵态氮,因此今后要对铵态氮的来源进行同位素示踪.     

Revisiting the abandoned shorelines of Lake George,Australia: a refined optical dating framework

Abandoned shorelines are an important archive used to constrain past fluctuations in the hydrological balance of lakes around the globe. Within Australia, the shorelines preserved at Lake George, NSW, form one of the few shoreline archives in the south-east of the continent that record palaeoenvironmental conditions throughout the late Quaternary. Here, we examined and tested the lake-level record for Lake George constructed in the 1970s by dating a well-preserved shoreline sequence at Luckdale, on the lake's eastern shore, using single-grain optically stimulated luminescence (OSL) dating. Ten stratigraphic units were identified, and these suggest a late Quaternary highstand for Lake George in MIS 3, with fluctuations superimposed upon an overall drying trend throughout MIS 2 and into the present. At Luckdale, the highest four shoreline-associated units were deposited ~13 to 19 m above lake base and date to between 39 ± 2 and 29 ± 1 ka ago. Our study pushes back the timing of maximum lake depth at Lake George to at least MIS 3, rather than MIS 2. The overall drying trend is supported by similar reductions in both Riverine Plain fluvial activity and other associated lake-level records from within the Murray basin.     

苏州西山震裂锥:太湖冲击坑又一新证据

震裂锥已被公认为陨石冲击地球表面遗留的标志。研究及统计资料表明,震裂锥与陨石冲击形成的中、大型冲击坑 有关。太湖西山震裂锥呈圆锥形,锥体表面有自锥顶向下辐射的锥纹,锥纹具有分叉的特征,这些特征与震裂锥的国际公 认的定义和标准相符。此外,西山震裂锥还具有其特有的其他特征：碎裂岩化显著;气化-熔融现象发育;锥体表面具网 状构造及波纹状、蜂窝状等多种气印。岩相学研究显示,震裂锥及含锥岩石中冲击变质现象明显,微页理（PDFs）、微裂 隙（PFs） 以及靶岩熔融现象发育。以上这些冲击变质的标志,可证明西山震裂锥是冲击成因,而非地表水风化淋溶石灰岩 的喀斯特或风蚀成因的凤稜石。西山震裂锥的发现、太湖湖底冲击击变角砾岩“太湖石”的确定,为太湖冲击坑的研究增 添了新的诊断性证据;加上早期研究确定的、冲击回落至太湖湖底淤泥层中的冲击溅射物,这些众多证据为确定“太湖冲 击坑”或“太湖冲击事件”展示了美好前景。但是,要确定太湖冲击坑的具体位置、大小及构造模式等,尚需更多的深入 研究。     

Temporal-spatial variations of euphotic depth of typical lake regions in Lake Taihu and its ecological environmental significance

Euphotic depth can be defined as the portion of wa- ter column that supports the net primary productivity. Its lower end is the critical depth, namely, the depth measured when the daily net primary productivity is zero[1]. In the ecosystems of oceans, lakes and rivers, phytoplankton live in the euphotic depth and euphotic depth is usually taken as the lower boundary, when studying the primary productivity and biomass of phytoplankton; therefore the corresponding depth is sometimes called the t…     

巢湖形成演变与现代沉积作用

通过地质调查, 钻孔样品分析及历史资料对比, 得出:1.巢湖位于在中新生代形成的巢湖断陷盆地南部, 形成于更新世发育的河谷平原上, 由于全新世受气候及相应海平面变化和长江河道演变等三者共同影响而积水成湖。成湖历史大约2000年左右, 属河成型浅水湖。2.湖底沉积物平均中值粒径5-6ф, 并形成有三角洲沉积, 开阔湖沉积等五种沉积类型, 东、西、中三湖区的沉积物中分別为0.21, 0.37, 0.14cm/a, 全湖年淤积总量为93×l0⁴t/a。3.湖泊污染加重起始于70年代, 磷除来自外源外, 内负荷引起的释放量达220.56t/a, 这对巢湖富营养化亦有着重要的影响。     

基于反射光谱和模拟MERIS数据的太湖悬浮物遥感定量模型

利用地物光谱仪研究了太湖水体的反射光谱特征,通过对比分析,发现580nm反射率值和810nm的反射峰高是太湖悬浮物的敏感波段,并通过光谱微分的方法,发现840nm附近的一阶微分与悬浮物浓度相关性最好,基于上述结论,分别建立了太湖悬浮物的反射光谱和一阶微分遥感定量模型,并利用反射光谱数据,模拟MERIS数据的波段设置,结果表明MERIS第5、12、13波段可以很好的估测太湖的悬浮物浓度.     

江西鄱阳湖地区土壤酸化与人为源氮的关系

江西鄱阳湖地区是我国土壤酸化严重的地区之一,对比研究区多目标区域地球化学调查与第二次土壤普查资料发现,研究区土壤酸化趋势严重,强酸性土壤占研究区面积比例由58.22%上升到78.44%;赣江、抚河水系入湖区和饶河流域表层土壤酸化明显。研究区因施肥、大气干湿沉降和灌溉输入到农田的氮素分别为123.84 kg.hm-.2a-1、74.13 kg.hm-.2a-1、11.02 kg.hm-.2a-1。研究区因人为氮带入农田的H+为18.67 kmol.hm-.2a-1。化肥氮是引起土壤酸化的主控因素,氮沉降也是影响土壤酸化的主要因素之一。土壤pH与氮含量呈较差负相关,说明土壤中的有机氮对土壤酸化作用有限,增施有机肥和复合肥,适当减少氮肥,特别是铵态氮肥的比例,可以补充盐基物质的相对不足,达到缓解土壤酸化的作用。土壤pH与钙含量呈极显著正相关,适量增施含钙物质可以有效地防止表层土壤酸度降低。     

Socio-hydrological framework for investigating farmers’ activities affecting the shrinkage of Urmia Lake; hybrid data mining and agent-based modelling

ABSTRACT

Developing a general framework to capture the complexities associated with the non-linear and adaptive nature of farmers facing water resources scarcity is a challenging problem. This paper integrates agent-based modelling (ABM) and a data mining method to develop a hybrid socio-hydrological framework to provide future insights for policy-makers. The data associated with the farmers’ main characteristics were collected through field surveys and interviews. Afterwards, the association rule was employed to discover the main patterns representing the farmers’ agricultural decisions. The discovered patterns were then used as the behavioural rules in ABM to simulate the agricultural activities. The proposed framework has been was applied to explore the interactions between agricultural activities and the main river feeding the Urmia-Lake, Iran. The outcomes indicate that farmers’ acquisitive traits and belongings have significant impacts on their socio-hydrological interactions. The reported values of the efficiency criteria may support the satisfactory performance of the proposed framework.