雄安新区地表覆盖变化及其新区规划的生态响应预测

雄安新区是新近设立的国家级新区,如何在新区建设中坚持生态优先、绿色发展,是即将开展的新区规划必须考虑的问题。绿色生态规划离不开对规划区生态本底的清楚认识,离不开对规划结果的准确预判。因此基于2004、2015年的Landsat影像,采用遥感信息反演技术和RSEI遥感生态指数,评估了该区近11年来的地表不透水面、植被和水体三大覆盖类型的变化,并预测新区建设的生态效应及其对热环境的影响。结果表明,雄安新区近11年地表不透水面、植被和水体的面积虽互有增减,但变化强度都小于5%,总体开发强度不大,本底生态质量较好,稳中略升。定量分析表明,在该区的三大地表覆盖类型中,不透水面对区域生态和地表温度的影响最大。根据所获得的关系模型预测,新区的人口规划和面积方案将对区域生态质量和热环境产生影响,如果按新增不透水面面积占新区面积25%的比例来预测,它将使生态质量下降10%,地表温度上升1.1℃;但如果将不透水面比例控制在20%,则新区的生态质量反而上升3.6%,地表温度下降0.3℃。     

三峡库区不同阶段蓄水前后江面江岸冬季鸟类动态

2003~2013年的隆冬季节(2011年除外),对三峡库区长江主河道的重庆朝天门港-秭归茅坪港江段(全程约618.30 km)和12条一级支流(合计调查河道长度约619.49 km),以及2个湖泊(长寿湖65.5 km~2,大洪湖30 km~2;调查年份2000~2013年,2003和2011年除外),进行了水禽及傍水栖息鸟类的监测调查。观察统计到鸟类76种,隶属8目14科39属,其中国家Ⅰ级重点保护野生动物1种,Ⅱ级重点保护野生动物3种。鉴于不同类群鸟类对环境变化的反应差别较大,将观察到的与水域生境密切相关的鸟类分为游禽类(32种)、鸥类(6种)、涉禽类(23种)、傍水栖息鸟类(13种)和空中傍水栖息鸟类[2种,以崖沙燕(Riparia riparia)为主体]等5种类型,并对各类群鸟类在三峡水库不同工程阶段蓄水高程前后的数量分布状况进行对比分析。结果显示,长江主河道中的游禽类在蓄水139 m高程前后数量波动幅度不大,蓄水156 m高程后表现出增长趋势,并且趋向于尾水点集中分布,直至最终蓄水目标175 m高程后的第5个冬季(2013年1月)数量猛增到最高,与蓄水139 m水位线前后的2个冬季(2003年1月和2004年1月)数量相比,增幅分别达171.83%和179.91%;然而2个湖泊中的游禽数值却表现出下降趋势,蓄水175 m高程后5个冬季(2008~2013年)与2000年冬季数值相比,降幅达52.96%~83.29%;大多数支流河道中的游禽数量呈现波动幅度不大或是明显下降趋势,只有乌江和小江这2条支流河道中的游禽数量呈现出增长趋势,并且小江中的游禽数量一度表现出"爆发式"增长现象后又大幅回落(2012~2013年),可能与水质富营养化程度的变化相关。涉禽类在长江主河道中的分布格局类似于游禽类(偏向于上游),其数量分别在蓄水139 m高程和156 m高程后的第1个冬季出现峰值,蓄水前后的其他年份数量差别不大;多数支流河道中涉禽类分布数量不高,只有嘉陵江、乌江、小江、大宁河与梅溪河的涉禽数量较多且数值波动明显。傍水栖息型鸟类总体数量在蓄水前后出现急剧变动,数量下降明显,个别鸟种甚至消失不见。空中傍水栖息型鸟类蓄水之后在长江主河道数量锐减,在大多数支流河道中几乎绝迹。鸥类主要分布在长江主河道,其数量在不同阶段蓄水初期出现峰值,至最终蓄水目标175 m后的第5个冬季其数量趋于接近蓄水之前。     

氮添加对三峡库区马尾松-栓皮栎混交林土壤微生物生物量和酶活性的影响

选择三峡库区的马尾松-栓皮栎混交林,分析不同浓度氮添加(0、30、60、90 kg N·hm-2·a-1)对土壤微生物生物量、酶活性和养分含量的影响,为在大气氮沉降持续增加的背景下预测该地区森林土壤碳动态提供科学依据.结果 表明:各氮添加处理下土壤有机碳、全氮和微生物生物量碳、氮、磷均显著提高,土壤pH值下降,全磷含量...     

三峡库区三种林下地被物储水特性

通过对三峡库区3种森林类型(松栎混交林、栓皮栎纯林、马尾松纯林)林下地被物调查及其持水试验,分别得到3种森林类型林下地被物最大储水量、吸水速率等水文特征参数,结果表明,栓皮栎纯林林下苔藓层储水量最大,为其风干重的303．1％,松栎混交林林下的为283．8％,马尾松纯林林下的为242．3％．松栎混交林林下枯落物最大储水量为其风干重的282.2％,栓皮栎纯林林下的为262．5％,马尾松纯林林下的为239．3％。经分析拟合,得到林下苔藓层、林下枯落物吸水速率与浸泡时间之间关系式为S=kt^n,在同为中龄林条件下,3种森林类型林下苔藓层储水量均高于林下枯落物储水量,而林下地被物储水量随时间变化过程与森林类型无关。     

GIS在描述某城区大气二氧化硫分布中的应用初探

应用地理信息系统（GIS）技术对1996年重庆市主城区大气二氧化硫分布进行了描述和分析。采用GIS的空间分析方法泰森多边形分析和区域插值对大气环境监测数据进行分析处理,避免了以点代面的缺陷,使大气污染物分布描述更为合理。     

Area under the free-response ROC curve (FROC) and a related summary index

Summary .  Free-response assessment of diagnostic systems continues to gain acceptance in areas related to the detection, localization, and classification of one or more "abnormalities" within a subject. A free-response receiver operating characteristic (FROC) curve is a tool for characterizing the performance of a free-response system at all decision thresholds simultaneously. Although the importance of a single index summarizing the entire curve over all decision thresholds is well recognized in ROC analysis (e.g., area under the ROC curve), currently there is no widely accepted summary of a system being evaluated under the FROC paradigm. In this article, we propose a new index of the free-response performance at all decision thresholds simultaneously, and develop a nonparametric method for its analysis. Algebraically, the proposed summary index is the area under the empirical FROC curve penalized for the number of erroneous marks, rewarded for the fraction of detected abnormalities, and adjusted for the effect of the target size (or "acceptance radius"). Geometrically, the proposed index can be interpreted as a measure of average performance superiority over an artificial "guessing" free-response process and it represents an analogy to the area between the ROC curve and the "guessing" or diagonal line. We derive the ideal bootstrap estimator of the variance, which can be used for a resampling-free construction of asymptotic bootstrap confidence intervals and for sample size estimation using standard expressions. The proposed procedure is free from any parametric assumptions and does not require an assumption of independence of observations within a subject. We provide an example with a dataset sampled from a diagnostic imaging study and conduct simulations that demonstrate the appropriateness of the developed procedure for the considered sample sizes and ranges of parameters.     

沈阳市四种乔木树种BVOCs排放特征

采用热解析与气相色谱联用技术对沈阳市4种主要乔木树种--银中杨、垂柳、榆树和皂角的BVOCs排放特征进行了观测.实验发现,不同树种排放BVOCs的组成情况明显不同,银中杨和垂柳以释放异戊二烯为主,且二者的BVOCs排放速率明显高于其他树种;榆树和皂角以释放柠檬烯为主.4种乔木树种BVOCs的释放具有显著的日变化和季节变化规律,各树种的BVOCs排放速率日变化曲线多表现为单峰型,排放高峰一般出现在中午或下午,且夜间几乎均不排放异戊二烯.季节变化趋势主要表现为夏季最高,春、秋季较低.     

Uncertainties in the response of a forest landscape to global climatic change

Many studies have been conducted to quantify the possible ecosystem/landscape response to the anticipated global warming. However, there is a large amount of uncertainty in the future climate predictions used for these studies. Specifically, the climate predictions can be very different based on a variety of global climate models and alternative greenhouse emission scenarios. In this study, we coupled a forest landscape model, LANDIS-II, and a forest process model, PnET-II, to examine the uncertainty (that results from the uncertainty in the future climate predictions) in the forest-type composition prediction for a transitional forest landscape [the Boundary Water Canoe Area]. Using an improved global-sensitivity analysis technique [Fourier amplitude sensitivity test], we also quantified the amount of uncertainty in the forest-type composition prediction contributed by different climate variables including temperature, CO₂, precipitation and photosynthetic active radiation (PAR). The forest landscape response was simulated for the period 2000–2400 ad based on the differential responses of 13 tree species under an ensemble of 27 possible climate prediction profiles (monthly time series of climate variables). Our simulations indicate that the uncertainty in the forest-type composition becomes very high after 2200 ad , which is close to the time when the current forests are largely removed by windthrow disturbances and natural mortality. The most important source of uncertainty in the forest-type composition prediction is from the uncertainty in temperature predictions. The second most important source is PAR, the third is CO₂ and the least important is precipitation. Our results also show that if the optimum photosynthetic temperature rises due to CO₂ enrichment, the forest landscape response to climatic change measured by forest-type composition may be substantially reduced.     

内蒙古巴特敖包地区早泥盆世牙形刺

内蒙古达茂旗(达尔罕茂明安联合旗)巴特敖包地区以碳酸岩相古生代地层发育而引人注意。经多年研究,特别是李文国等(1985)的研究,使本区珊瑚、腕足类、层孔虫、鹦鹉螺等大化石的研究工作已有一定基础,并依据牙形刺首先确定了在阿鲁共剖面有泥盆纪地层的存在。但本区泥盆纪地层仍存在很多问题,必须通过对牙形刺的研究加以解决。在王成源研究员的精心安排和亲自指导下,作者等在巴特敖包地区的七个剖面进行了系统取样研究。经对158个样品(重667kg)的分析,在本区发现了大量的原定为志留纪的早泥盆世地层,包括西别河组命名剖面。分析结果同时证明,本区不存在志留系温洛克统的沉积。巴特敖包剖面断层发育,志留—泥盆纪地层交替出现,巴特敖包组应取消,原定的阿鲁共剖面层序颠倒。本区地层应厘订为志留系的西别河组(罗德洛统—普里道利统)和下泥盆统的阿鲁共组(Lochkovian阶),前者以包尔汉图剖面为标准剖面,后者应寻找更好的标准剖面。本文重点总结巴特敖包地区早泥盆世的牙形刺。本区共建立了4个牙形刺带,文中共描述了8牙形刺属,21种,其中包括4亚种、1新种(Belodellataeniocuspidatasp.nov.)和1未定种。     

子午岭林区白桦-辽东栎混交林光合生理生态特征研究

对黄土高原子午岭次生林区白桦林、辽东栎林和白桦-辽东栎混交林3种林分的土壤物理特性和叶片光合特性进行了研究。结果表明:(1)白桦-辽东栎混交林地的土壤水分明显改善,其土壤容重最小、土壤孔隙度最大,且均优于纯林,即混交林地有深层次的土壤水分可供利用,并改善了土壤的物理结构;(2)辽东栎林的光合速率和气孔导度最大,其次为白桦-辽东栎混交林,水分利用率(WUE)为混交林白桦>混交林辽东栎>辽东栎林>白桦林;(3)混交林中白桦、辽东栎的Fv/Fm和Fv/Fo值均较大,与纯林差异不显著;白桦林和辽东栎林的qP和NPQ值均大于混交林。