新疆主要城市不同生态功能区夏季空气负离子特征   总被引：2，自引：0，他引：2  

张毓涛  李吉玫 《干旱区地理》2012,35(6):864-874

在不同天气状况下,对新疆8个主要城市5种生态功能区（林地、水体、景区、商业区和生活区）空气负离子浓度监测。结果表明：（1）不同生态功能区间空气负离子浓度差异显著（F=51.960,P= 0.000<0.001）,顺序为林地(431个/cm³)>景区(398个/cm³)=水体(398 个/cm³)>生活区(313个/cm³)>商业区(270 个/cm³);（2）各功能区空气负离子浓度日变化均表现为清晨和傍晚高于午间。单因素方差分析表明林地、水体和景区午间空气负离子浓度与清晨和傍晚的差异不显著,生活区和商业区差异显著;（3）景区和林地[WTBX]CI[WTBZ]值（0.50和0.49）处于中等清洁范围,属C级;水体和生活区[WTBX]CI[WTBZ]值（0.45和0.29）处于容许范围,属D级;商业区CI值（0.24）在临界值以下,属E级;（4）从林地、水体、景区、生活区到商业区,D级和E级天气所占比例不断增加,B级和C级天气不断减少,说明空气质量逐步下降;（5）不同天气状况下各功能区空气负离子均表现为雨天>晴天>阴天>沙尘（浮尘）。  相似文献   

Testing the reliability of pollen-based diversity estimates   总被引：2，自引：2，他引：0  

Matthew Charles Peros  Konrad Gajewski 《Journal of Paleolimnology》2008,40(1):357-368

Rarefaction analysis is a common tool for estimating pollen richness. Using modern and fossil pollen data from the Canadian Arctic and Greenland, we examine the effects of pollen concentration (grains/cc) and evenness (the distribution of species abundances) on palynological richness. Our results show that pollen richness and concentration have a strong negative correlation at low pollen concentrations. There is a positive correlation between pollen evenness and richness, although the strength of this relationship is difficult to determine. Rarefaction analysis on samples of low concentration or high evenness is likely to lead to pollen richness being less underestimated than on samples of high concentration or low evenness. These findings corroborate theoretical research on these issues.  相似文献   

Difference in diet and age structure of blue and white Arctic foxes (Vulpes lagopus) in the Disko Bay area, West Greenland     

Sussie Pagh  & Páll Hersteinsson 《Polar research》2008,27(1):44-51

  相似文献   

半横向通风方式隧道内污染物分布的数值仿真   总被引：1，自引：0，他引：1  

任锐  谢永利  楼慧元 《地震学刊》2011,(1):96-101

某城市公路隧道采用半横向通风方式进行火灾排烟,其排风孔位于隧道侧壁顶部。针对该城市公路隧道,运用CFD数值仿真方法建立1：1的三维数值仿真模型,模拟不同工况下,开启不同形状排风孔时,隧道内的风速、风压以及污染物浓度的分布情况。研究表明,排风孔所在位置的隧道横断面上,形成一个左侧区域负压较高、压强变化梯度大而右侧区域负压较小的＂排风横断面＂;随着排风孔开口高度的增加,排风横断面上负压分布向右侧扩大,右侧区域风速增加,有利于右侧区域内污染物的稀释,而左侧区域竖直方向风速减小,左下角区域风流方向紊乱,左侧区域污染物不能得到有效稀释,浓度较高。  相似文献   

风云三号气象卫星红外分光计探测大气CO2浓度的通道敏感性分析     

戴铁  石广玉  漆成莉  徐娜  张兴赢  杨溯 《气候与环境研究》2011,16(5):577-585

依据红外分光计（InfraRed Atmospheric Sounder,IRAS）光谱通道特征,发展了基于IRAS的大气辐射传输计算模式。以大气分子吸收光谱数据集（HIgh resolution TRANsmission,HITRAN） 2004为初始谱线输入资料,利用该模式模拟计算IRAS在CO2 吸收带的10个通道辐射率测值对CO2浓度变化的响应,并对比了其与大气温度和水汽、O3等气体浓度误差对辐射率测值的影响,探讨了利用风云三号气象卫星探测大气CO2浓度的可行性。结果表明,IRAS的通道4最适于用来监测大气CO2浓度的变化,当CO2体积混合比浓度变化在10×10-6时,对应的辐射率变化同仪器等效噪声辐射率相当,所以IRAS在理想状态下,最高可分辨的大气CO2浓度变化约为10×10-6。  相似文献   

东濮凹陷西部斜坡带油田水特征及其油气地质意义   总被引：1，自引：0，他引：1  

满红梅  叶加仁  李令喜  徐俊杰  王继立 《地质科技情报》2009,28(3)

基于实际测试资料,统计分析了东濮凹陷西部斜坡带沙河街组油田水的水型、矿化度、盐类离子组分和化学系数的纵、横向变化特征,并探讨了油田水特征对油气聚集与保存的指示作用。研究表明,研究区油田水以CaCl2型为主;矿化度随埋深增大而增大,Ⅱ台阶发育高矿化度区;常规离子组成中阳离子为Na^＋ ＋K^＋、Ca^2＋、Mg^2＋;阴离子为C1^-、SO4^2-、HCO3^-,并以Na^＋＋K^＋和Cl^-占绝对优势,在深层高矿化度区存在阳离子交替吸附现象;由浅至深、自Ⅲ台阶到Ⅰ台阶,钠氯系数、脱硫系数、碳酸盐平衡系数和钠钙系数呈减小趋势,而变质系数和钙镁系数则逐渐增大;油田水分布特征指示着研究区深层的油气保存条件优于浅层,从西部斜坡带顶部到洼陷中心油气保存条件越来越好,Ⅱ台阶是重要的油气聚集区带与勘探对象。  相似文献   

Nitrogen fixation in polluted intertidal sediments of Waimea Inlet,Nelson     

B. Ben Bohlool 《新西兰海洋与淡水研究杂志》2013,47(3):271-275

Abstract

Nitrogen fixing potential was measured in summer 1975 by acetylene reduction in situ at 5 stations on the intertidal flats of the Waimea Inlet, Nelson, New Zealand, which receive nutrients from several sources. Highest values (644 μmol?m^?2.d^?1) were obtained on sediments near an apple cannery effluent discharge and were linear through at least two tidal cycles. The cannery waste had the highest carbon to nitrogen ratio (10.3 : 1.0) of all the effluents examined and exhibited the highest rate of acetylene reduction (14.0 μmol?_‐l^?1.d^?1). Sizeable populations of the nitrogen fixing bacteria Klebsiella pneumoniae were isolated from the cannery effluent (2 × 10⁴ per millilitre) and also from the mud adjacent to the discharge pipe (5 × 10⁵ per millilitrc). The stimulatory effect of the cannery effluent on nitrogen fixation in the sediment was shown to be restricted to close to the discharge point. Sediments in areas affected by slaughterhouse and sewage effluents exhibited the second and third highest rates of acetylene reduction, (130 &; 28 μmol?m^?2.d^?1 respectively). In both places, the activities were not restricted to the immediate vicinity of the effluent channels. Nitrogen fixation was lowest in sediments fronting a catchment of grazed pasture. Fixation was low also in sediments affected by effluents from the hydraulic debarker of a woodchip mill.  相似文献   

Diets of alpine galaxias (Galaxias paucispondylus Stokell) and longjawed galaxias (G. prognathus Stokell) in a South Island,New Zealand,high‐country stream     

M. L. Bonnett  P. M. Sagar  C. R. Docherty 《新西兰海洋与淡水研究杂志》2013,47(4):453-458

Thedietsofthealpinegalaxias(Galaxias paucispondylus Stokell, 1938) and the longjawed galaxias (G. prognathus Stokell, 1940) were studied in Deep Creek, a high‐country stream in the central South Island of New Zealand. Both species are small, slender fish with entirely freshwater life cycles. Their diets were very similar and consisted of aquatic invertebrates, dominated by the larvae of Deleatidium spp. (Ephemeroptera), Hydrobiosis spp. (Trichoptera), and Chironomidae (Diptera). Although diets partly reflected what was available in the stream, both fish selected soft‐bodied prey in preference to cased or harder shelled prey. Both species are probably nocturnal feeders.  相似文献   

Planktonic stages of the teleost family carapidae in eastern New Zealand waters     

D. A. Robertson 《新西兰海洋与淡水研究杂志》2013,47(3):403-409

The occurrence of planktonic carapid eggs in Otago waters, of young stages of Echiodon rendahli off Castlepoint, and the possible presence of unrecorded members of the family Carapidae in New Zealand waters is discussed. Young E. rendahli possess a long spine which originates dorsally to a distinctive suspended gut.  相似文献   

Growth,diet, movement,and abundance of adult banded kokopu (Galaxias fasciatus) in five Coromandel,New Zealand streams     

David W. West  Ian G. Jowett  Jody Richardson 《新西兰海洋与淡水研究杂志》2013,47(4):915-929

Banded kokopu populations were surveyed seasonally over 1 year in five Coromandel streams to determine the influence of food supply on diet, growth, abundance, and movement. Streams with high benthic invertebrate abundance and drift of aquatic origin had high fish abundance. However, terrestrial drift was the dominant food for adult banded kokopu over all seasons and streams, on average comprising 75% of their diet by number and 89% by weight. Annual growth rates of tagged individuals ranged from 3 mm to 16.5 mm, with smaller fish growing faster than large fish. Low growth rates of large fish were consistent with the recapture of a fish that had only grown from 195 mm to 215 mm in 7 years. Our observations confirmed the strong association between banded kokopu, pool habitat, and cover, and also indicated that high fish abundance restricted growth rates and movement and increased interaction.  相似文献