内蒙古东部地区小叶杨物候变化与气象条件的关系

利用数理统计方法对近20-30 a内蒙古东部主要牧业试验站的气候变化及小叶杨的物候变化进行探讨,研究小叶杨的物候变化与气象条件的关系。结果显示：近20-30 a来大于等于0℃的初日提早,终日推后,积温显著增加。上半年的物候现象(花芽开放期、展叶始期、展叶盛期和开花始期)提前;下半年物候现象(叶全变色期、落叶末期)及开花盛期均推迟。小叶杨自然物候现象存在着明显的地域性差异。小叶杨上半年的物候期与气温呈显著负相关,而下半年的物候期与气温呈显著正相关;物候期变化对温度的响应较强,其关系有可能是非线性的。日照和降水对物候期变化的影响,由于其地理位置和生育时段的不同而呈现各不相同的关系。小叶杨物候期的变化对降水和日照的响应不明显。     

青藏高原腹地湖泊沉积纪录的“仙女木期”古气候颤动事件

通过对青藏高原腹地钻孔岩心剖面的最新研究,用层序地层学与年代地层学和气候地层学相结合的方法,分辨出可可西里地区苟弄措湖泊沉积记录(孔深7.25 m)约30 ka BP以来的古气候变化,并在孔深3.32～1.98 m处识别出“仙女本期”的3个气候颤动事件,即:①老仙女术事件(孔深3.32～2.62 m);②中仙女本事件(孔深2.62～2.43 m);③新仙女本事件(孔深2.43～1.98 m)。这3个气候颤动事件都是以冷干时段开始、以冷湿时段结束的,并有越向后期其冷干的时段越长的变化趋势,而其后的冷湿时段却具有等时的变化趋势。岩心沉积物的有机碳、有机氮和磁化率以及化学元素含量的变化,都与仙女本期气候变化具有十分吻合的变化态势。仙女术期气候在湖泊沉积物中的响应,在青藏高原环境演化中还是首次发现,为研究第四纪末次冰期冰消期以来的气候变化提供了新的信息。     

ANALYSES OF A MICROPHYSICAL RESPONSE TO THE SEEDING IN TWO CASES OF ARTIFICIAL FOG DISSIPATION

Two field experiments were performed in order to dissipate the fog at Wuqing District of Tianjin in November and December of 2009.Hygroscopic particles were seeded to dissipate fog droplets on 6-7November,2009.Liquid nitrogen(LN)was seeded into the natural supercooled fog in the experiments of 30November–1 December,2009.Significant response was found after seeding.Significant changes were observed in the microstructure of fog in the field experiments.The of fog droplet changed dramatically;it increased first and then decreased after seeding.Remarkable variation also was found in the Liquid Water Content(LWC)and in the size of fog droplet.The Droplet Size Distribution(DSD)of fog broadened during the seeding experiments.The DSD became narrow after the seeding ended.After seeding,the droplets were found to be at different stages of growth,resulting in a transform of DSD between unimodal distribution and bimodal distribution.The DSD was unimodal before seeding and then bimodal during the seeding experiment.Finally,the DSD became unimodally distributed once again.     

Deep incision in an Aptian carbonate succession indicates major sea‐level fall in the Cretaceous

Long‐term relative sea‐level cycles (0·5 to 6 Myr) have yet to be fully understood for the Cretaceous. During the Aptian, in the northern Maestrat Basin (Eastern Iberian Peninsula), fault‐controlled subsidence created depositional space, but eustasy governed changes in depositional trends. Relative sea‐level history was reconstructed by sequence stratigraphic analysis. Two forced regressive stages of relative sea‐level were recognized within three depositional sequences. The first stage is late Early Aptian age (intra Dufrenoyia furcata Zone) and is characterized by foreshore to upper shoreface sedimentary wedges, which occur detached from a highstand carbonate platform, and were deposited above basin marls. The amplitude of relative sea‐level drop was in the order of tens of metres, with a duration of <1 Myr. The second stage of relative sea‐level fall occurred within the Late Aptian and is recorded by an incised valley that, when restored to its pre‐contractional attitude, was >2 km wide and cut ≥115 m down into the underlying Aptian succession. With the subsequent transgression, the incision was backfilled with peritidal to shallow subtidal deposits. The changes in depositional trends, lithofacies evolution and geometric relation of the stratigraphic units characterized are similar to those observed in coeval rocks within the Maestrat Basin, as well as in other correlative basins elsewhere. The pace and magnitude of the two relative sea‐level drops identified fall within the glacio‐eustatic domain. In the Maestrat Basin, terrestrial palynological studies provide evidence that the late Early and Late Aptian climate was cooler than the earliest part of the Early Aptian and the Albian Stage, which were characterized by warmer environmental conditions. The outcrops documented here are significant because they preserve the results of Aptian long‐term sea‐level trends that are often only recognizable on larger scales (i.e. seismic), such as for the Arabian Plate.     

“浣熊”强度变化的环境背景和卫星观测分析

利用实况观测定位和强度资料、NCEP的1°×1°全球最终分析资料、NOAA周平均1°×1°海温再分析资料和FY卫星水汽图像,分析台风浣熊(0801)的环境背景条件和内核结构演变与强度变化的关系.结果表明:(1)环境风垂直切变增大至10m·s~(-1)左右与南海北部海表温度逐步减小导致最大可能强度不断降低是"浣熊"快速发展过程中断并减弱的重要外部条件;(2)卫星水汽图像显示内核结构存在眼壁破裂和复原现象,该现象精确地反映其强度变化.眼壁破裂(复原)过程导致"浣熊"减弱(增强).     

1961-2010年新疆极端降水过程时空特征

采用新疆50个气象测站1961-2010年逐日降水资料,选用14个极端降水指数探讨新疆极端降水事件的发生与变化。结果表明：无论平均降水过程还是极端降水过程,均能反映新疆明显的湿润化趋势。伴随降水量的增加,降水强度及降水频率均增大,除CDD变化表现为下降趋势外,其他指数变化均呈上升趋势。分析各极端降水指数序列变化,20世纪60-70年代年际变化幅度小,稳定性好;80-90年代年际差异大,稳定性差;新疆东部各极端降水指数上升与下降趋势小幅交替出现,而北疆、南疆及全疆极端指数序列则呈明显且单一的上升趋势。各极端降水指数最大概率变异年为1986年、2009年;降水变异后,新疆弱降水过程变化不明显,但强降水过程变幅增大,易导致洪旱灾害等极端气象水文事件的发生。     

复合荒漠化及其时空变化研究——以新疆艾比湖地区为例

以新疆艾比湖地区为研究区,通过对现有荒漠化监测指标体系的归纳分析,界定了复合荒漠化概念.利用遥感影像数据提取研究区各类荒漠化的现状与动态变化信息.研究结果表明:单一主导因子荒漠化类型面积占荒漠化土地总面积的82.29%,复合荒漠化面积占17.71%.2002～2005年,艾比湖湖面面积缩小了322.507 3 km2,相应的总体土地荒漠化面积增加了7.18%,复合荒漠化面积增加了133%.土地荒漠化的过程同时也发生了变化,风蚀、复合荒漠化增加而土地盐渍化减少,荒漠化程度加重,复合荒漠化类型增加并向其他土地类型扩展.     

广东省“人口—经济—土地—社会—生态”城市化协调度时空变化及其聚类模式

多维城市化协调度评价是衡量区域城市化质量的重要方面,探究城市化时空聚类模式则是分析区域城市化特征的有效方法。针对目前城市化协调度评价缺乏多维度时空综合分析的现状,本文以广东省为例,提出一种基于时空权重矩阵的复杂时空系统协调度评价模型,运用此模型分析2006-2014年城市化协调度的时空变化特征,并借助时空扫描方法分析其聚类模式。研究结论为：①近10年来城市化水平呈现3种时序特征,人口城市化水平表现出随时间均衡发展的“集中”特征,而经济与土地表现出低频次的“集中与分散”交替,社会、生态及综合水平表现出高频次的“集中与分散”交替;稳定型城市主要位于珠三角核心区。②各维度及综合系统协调度时空聚类区既有空间分异性又有重叠性,人口协调度时空聚类于粤西地区,经济与土地维度协调度时空聚类高度重合于珠三角与粤北地区,社会与生态维度协调度时空聚类交叉于珠三角与粤东地区,而综合系统协调度居中。此外,时空聚类区的人口、经济与社会维度的协调度稳定性要优于土地与生态维度。本文结论有助于揭示区域城市化的时空特征。     

Exploring LiDAR data for mapping the micro-topography and tidal hydro-dynamics of mangrove systems: An example from southeast Queensland,Australia

The aim was to explore the use of Light Detection and Ranging (LiDAR) data to map the micro-topography of an intertidal wetland in southeast Queensland Australia. The driver for this was the need to identify and map the habitats of the immature stages of an aedine disease vector mosquito (Aedes vigilax (Skuse)). We derived a high resolution digital elevation model (DEM) data set at a vertical resolution of 0.05 m from LiDAR data. The relative accuracy of the DEM across the site was tested by comparing water depth predictions derived from the DEM against in-situ water depth readings from pressure sensors over a 10-day tidal cycle, which included high spring tides. We found that the field observations of micro-topographic units important for mosquito management matched those delineated from the DEM. The micro-topography included a low berm or central ridge that was more or less continuous across the site, a shallow back basin and fringing mangroves. The fringing mangroves had unimpeded connection to the tidal source, however the central ridge blocked tidal water from the back basin for all but the highest tides. Eggshell survey indicated that the back basin was the area suitable for immature mosquitoes. We conclude that LiDAR data has application for understanding and mapping the structure of mangrove wetlands. We have also demonstrated (in a small area) that LiDAR is useful for modelling the effect of sea level changes on the coastal fringe. LiDAR may be the only method to inform research on changes to land use and ecosystems caused by sea level change.