柴达木盆地东南部土壤风蚀研究

柴达木盆地东南部土壤风蚀风洞模拟实验结果表明,土壤风蚀强度随风力作用和下垫面因子不同而不同。净风对土壤风蚀作用较小,但在挟沙风作用下,风蚀强烈。地表类型不同风蚀强度变化很大,流动沙地是耕地(小麦留茬)的数百倍。土壤质地不同起沙风速不同,细沙和极细沙比例越高风蚀量越大。翻耕地与未翻耕地风蚀变化悬殊,翻耕地风蚀量是未翻耕地的10倍以上。自然植被和人为留茬均有抑制风蚀的作用。     

赛里木湖区风景名胜资源调查评价

本文对赛里木湖风景区开展了系统深入的野外考察研究，表明该区风景名胜资源别具异彩，不愧为“西来之异境”世外之灵壤”。     

广州市土地资源的保护和可持续利用研究

本文分析了广州市土地利用的结构及其变化趋势，指出土地利用上存在的主要问题和隐患 为采取有效措施，加强对耕地和环境的保护，以保证土地资源的可持续利用。     

广州市人口空间分布特征及演变趋势分析

本文分析了广州市人口空间分布现状特征，历史上发展特点和建国后至改革开放前人口发展情况，并对改革开放以来人口空间分布的变化作了动态分析，发现改革开放以前广州市中心区和郊区人口密度都在增加，但市中心区增加较快，而改革开放以来在广州市总人口较速增长的情况下，内部人口变动日趋明显，中心区人口密度在减少，外围区人口密度在增加，认为广州市的人口分布正从年龄阶段转向成熟阶段。     

中国西北部“4.5”沙尘暴过程中尺度低压的数值模拟

利用改进型ＰＳＵ／ＮＣＡＲ中尺度数值模式（ＭＭ４标准版），取模式水平格距４０ｋｍ，４６×６１网格，垂直方向ａ取１５层，即从地面到模式顶（１００ｈＰａ），σ＝０．０、０．１、０．２、０．３、０．４、０．５、０．６、０．７、０．７８、０．８４、０．８９、０．９３、０．９６、０．９８、０．９９、１．００，采用ＮＣＡＲ的３０＇×３０＇地形资料，以常规观测资料作为初始场，较好地模拟了此次沙尘暴过程的海平面气压的演变和分布，特别是张掖、柴达本盆地以及敦煌附近的三个中低压。同时，模拟了张掖中低压与蒙古冷高压之间的甘肃河西沙尘暴东大风。敏感性试验表明，沙尘暴中低压的形成发展主要是受于物理过程制约；沙尘暴中尺度系统的研究与暴雨中尺度系统的研究是有区别的，积云对流参数化并不是特别重要，在设计研究沙尘暴的数值模式中，应当合理地处理其他的热力、动力过程及大气外强迫源的作用。模式水平格距、地形真实程度对模拟中低压的位置、中心强度有重要贡献；下垫面变化中低压强度有一定影响。张掖热低压的形成发展主要是在有利的环境形势下，特殊地势起了重要作用，表现为直接动力强迫和间接热力强迫。     

长三角制造业转型升级的粘性机理及其实现路径——基于“微笑曲线”成因的视角

利用"微笑曲线"指导制造业的转型升级已经成了众多研究者的选择,且得出的结论基本都是制造业要转型升级就要向两端攀升,而对"微笑曲线"成因的研究则较为鲜见。用创新论、劳动论、市场论阐释了"微笑曲线"的成因,并以此作为突破影响长三角制造业转型升级粘性的基础理论,指出长三角制造业转型升级的路径为:遵循竞争优势理论,针对应该重点发展的制造业,根据劳动的复杂程度以及产品是否有标准接口对制造业进行分类,继续做好做优精细复杂的行业、转移出去粗放简单的行业,同时,还应该积极促进产业融合,发展新兴产业,在积累的基础上实现转型升级。     

Late Tertiary paleoclimatic interpretation from lacustrine rhythmites in the Gray Fossil Site,northeastern Tennessee,USA

The Gray Fossil Site (GFS) includes a small (<2 ha) paleosinkhole lake fill with an exceptionally well-preserved record of sedimentation and fossils from the latest Miocene to earliest Pliocene. The uppermost lacustrine stratigraphy is characterized by rhythmites that regularly alternate between coarse-grained and organic-rich (A) laminae and fine-grained, silty clay (B) laminae. Both the A and B components are almost exclusively comprised of exogenic sediment (including organic matter). Periodicities of 24 and 4.4 are recorded within a continuous 96 interpreted year sequence of rhythmite sediment. In a small lake with a poorly oxygenated bottom, the presence of laterally continuous laminated sediment that includes well-known periodicities in rhythmite thickness is interpreted as representing annually generated varves that correspond to seasonal variations in sedimentation. The distinctly larger fraction of medium sand-size quartz grains present within the A laminae, as well as the abrupt transitions between A and B components suggest that the rhythmites represent deposition during alternating high-energy and lower-energy seasons, which is consistent with a monsoonal precipitation pattern. The seasonal climate may relate to changes in the ocean circulation pattern prior to 4.6 Ma that resulted in an increased temperature and atmospheric pressure gradient between the east coast of North America and the Atlantic Ocean, but this climate phase seems to be only a temporary condition, as underlying and overlying sediment are both consistent with drier conditions. The periodicity at 24 interpreted years is consistent with the well-known Hale solar cycle. The 4.4 interpreted-year periodicity occurs within the ENSO frequency band, and if this documentation of ENSO-like interannual climate change is correct, then it suggests that ENSO operated at times during the warm Earth conditions characterizing the late Tertiary.     

Sedimentary pellets as an ice-cover proxy in a High Arctic ice-covered lake

Sediment aggregates (“sedimentary pellets”) within the sedimentary record of Lake A (83°00′ N, 75°30′ W), Ellesmere Island, Canada, are used to construct a 1000 year proxy record of ice-cover extent and dynamics on this perennially ice-covered, High Arctic lake. These pellets are interpreted to form during fall or early winter when littoral sediment adheres to ice forming around the lake’s periphery or during summer through the development of anchor ice. The sediment likely collects in ice interstices and is concentrated in the upper ice layers through summer surface ice melt and winter basal ice growth. The pellets remain frozen in the ice until a summer or series of summers with reduced ice cover allows for their deposition across the lake basin. Sedimentary pellet frequency within multiple sediment cores is used to develop a chronology of ice-cover fluctuations. This proxy ice-cover record is largely corroborated by a record of unusual sedimentation in Lake A involving iron-rich, dark-orange to red laminae overlying more diffuse laminae with a lighter hue. This sediment sequence is hypothesized to represent years with reduced ice cover through increased chemocline ventilation and iron deposition. During the past millennium, the most notable period of inferred reduced ice cover is ca. 1891 AD to present. Another period of ice cover mobility is suggested ca. 1582–1774 AD, while persistent ice cover is inferred during the 1800s and prior to 1582 AD. The proxy ice-cover record corresponds well with most regional melt-season proxy temperature and paleoecological records, especially during the 1800s and 1900s.

Epiphytic diatoms as flood indicators

The hydroecology of floodplain lakes is strongly regulated by flood events. The threat of climate warming and increasing human activities requires development of scientific methods to quantify changes in the frequency of short-lived flood events, because they remain difficult to identify using conventional paleolimnological and monitoring approaches. We developed an approach to detect floods in sediment records by comparing the abundance and composition of epiphytic diatom communities in flooded and non-flooded ponds of the Peace-Athabasca Delta (PAD), Canada, that grew on submerged macrophytes (Potamogeton zosteriformis, P. perfoliatus) and an artificial substrate (polypropylene sheets) during the open-water season of 2005. Analysis of similarity tests showed that epiphytic diatom community composition differs significantly between flooded and non-flooded ponds. After accounting for the “pond effect,” paired comparisons of the three substrates determined that variation in community composition between the artificial substrate and macrophytes was similar to that between the macrophyte taxa. Similarity percentage analysis identified diatom taxa that discriminate between flooded and non-flooded ponds. The relative abundance of ‘strong flood indicator taxa’ was used to construct an event-scale flood record spanning the past 180 years using analyses of sedimentary diatom assemblages from a closed-drainage pond (PAD 5). Results were verified by close agreement with an independent paleoflood record from a nearby flood-prone oxbow pond (PAD 54) and historical records. Comparison of epiphytic diatoms in flooded and non-flooded lakes in this study provides a promising approach to detect changes in flood frequency, and may have applications for reconstructing other pulse-type disturbances such as hurricanes and pollutant spills.