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1.
利用海南省儋州市自动气象站近60年逐日雷暴观测资料和近13年雷电灾害资料,分析了儋州雷暴活动和雷电灾害的年际变化和月分布特征以及雷击造成的人员伤亡和财产损失特征。结果表明:儋州市近60年平均年雷暴日数为112天,儋州年雷暴日呈现出明显的下降趋势;儋州雷暴日主要集中在4至10月,盛发期为5至9月;儋州雷电灾害也主要发生在5至9月;儋州雷击人员伤亡绝大多数发生在农村,雷灾及其造成的财产损失最频繁发生在电子系统。 相似文献
2.
丁旻 《防灾技术高等专科学校学报》2013,(4):36-42
利用1961—2011年贵州省87个台站地面雷暴观测资料,对该省境内雷暴日数的时空分布、周期和突变特征进行了分析。结果表明:贵州省雷暴日数年际变化较大,下降趋势显著;雷暴日数的时空分布形态不对称,92.16%正偏,峰度76.47%为正值,48a贵州区域内空间分布在0.05置信水平上服从正态分布。雷暴日数分布地域特征明显,从贵州西南部向东北方向呈梯状递减趋势,安顺市、六盘水市和黔西南州3个地区为雷暴高发区。贵州省逐年雷暴日数存在不太明显的18a左右的长周期以及4—5a和8—9a显著的周期变化。贵州省年雷暴日数的下降是一突变现象,具体是从1995年开始的,突变前后平均雷暴日数相差9.32d。 相似文献
3.
1967-2012年长丰雷暴气候特征分析 总被引:1,自引:0,他引:1
刘江 《防灾科技学院学报》2016,(1):37-41
利用江淮之间北部地区的长丰站1967-2012年的逐日观测雷暴数据,通过线性倾向估计和Mann-Kendall检验法研究雷暴的气候特征.结果表明:长丰站年平均雷暴日数为27.3d,雷暴日数年代际线性变化呈下降趋势,气候倾向率为-2.74d/10a.逐月平均雷暴分布与月平均气温、降水量呈现同相单峰形,7月雷暴出现高峰值,9月雷暴锐减.Mann-Kendall法检验显示,雷暴日数有着显著的下降趋势,突变发生在1977年,并在1982年突破了显著性α =0.05的临界值. 相似文献
4.
利用1959—2011年马鞍山地区4个观测站53年的逐日人工雷暴观测资料,通过surfer软件绘图计算、经验正交分解(EOF)、建立时间序列以及气候趋势等方法,分析了马鞍山雷电时空变化特征。结果表明:马鞍山雷暴日数呈现东西部、南部偏多,中北部偏少的特点,时间分布上雷暴日数呈下降走势,其气候倾向率为-5.3/10a,季节性分布上主要集中在夏季,雷暴期有延长的趋势,日变化规律十分明显,午后13时至夜间为雷暴出现高峰期。 相似文献
5.
《防灾科技学院学报》2015,(3)
本文基于信息扩散的模糊数学理论模型,以贵州各区县1986—2010年的雷暴日观测数据为集值,分析各区县的雷暴活动强度分布情况,为防雷工程的合理化设计提供依据。分析结果表明:全省各区县雷暴活动强度以中、多雷暴区为主,其中少、中、多、强雷暴的发生概率分别为低于10.78%、低于61.82%、介于29.42%至99.85%之间、低于6.10%。雷暴活动强度区域分布大致随纬度变化,强雷暴、多雷暴、中雷暴、少雷暴频发区呈现由西南向北分布;其中西南部安龙、兴仁、盘县雷暴日高于90天的可能性高于其他区域,约为20a一遇;雷暴日不大于25天最可能发生在北部仁怀、赤水、务川等地,呈现10~20a一遇。 相似文献
6.
近50年贵州省雷暴气候特征分析 总被引:1,自引:0,他引:1
利用贵州79个观测站1962—20¨年雷暴观测资料,采用经验正交函数分解(EOF)、小波分析和Mann—kendall检验,研究了贵州雷暴的气候变化特征。结果表明:全省雷暴活动西南向东北沿线逐渐减弱,东南向西北部减弱;根据EOF分析,雷暴异常空间分布主要有以下三类:全区一致型、纬向型、经向型,即同增同减、北多(少)南少(多)、东增(减)西减(增),以全区一致型表现最为明显,其方差贡献为66.16%;此外,年际变化存在8~10年长周期、2~3年短周期振荡变化,且自1986年发生突变,总体呈现减弱的趋势,尤其以90年代以来最为显著,并推测未来几年全省雷暴活动将持续维持在偏少期。 相似文献
7.
为提升中国石化海南省石油分公司雷电应急响应及预防能力,减少因雷灾引起的伤亡事故,组建了覆盖海南省的新型蜂窝布局雷电预警网,对海南地区的雷电活动进行实时预警。使用地闪定位数据对蜂窝布局雷电预警系统的预警效率进行统计分析。结果表明:该系统的有效预警可达到85. 5%,错误预警率约为73%,初步认为错误预警率偏高主要是由于预警系统对云闪造成的电场变化探测灵敏,而用来作为对比分析的闪电定位资料对云闪的探测效率较低造成的。 相似文献
8.
利用1961~2006年陇东黄土高原气象观测站的雷暴资料,运用数理统计、函数分解、图表分析方法,分析了雷暴的时空分布特征.(结果表明:陇东雷暴次数的年际变化总体上呈波动状态,60年代为雷暴多发期,70年代波动明显,大致存在4.5年的振荡周期,80年代为增长期,以5年为周期振荡,90年代开始至今以4年为周期振荡并呈现减少趋势.根据41年NCEP/NCAR再分析格点资料,并考虑下垫面热力作用,用统计分析方法得到判别陇东黄土高原雷暴有无的预报函数,建立了雷暴短期短时预报的判别模型.检验表明:雷暴短期短时预报模型是可行的,2005~2006年试报,雷暴预报出现宰可达61.7%,在同一时效下模型的预报水平要高于预报员的主观预报. 相似文献
9.
福州区域雾霾天气时空分布特征分析 总被引:14,自引:1,他引:13
利用1968~2007年共40年的福州区域9个气象站的历史地面观测资料,分析雾霾天气的时间分布特征及其原因。结果表明:40年间,福州区域雾日最多的是永泰站,轻雾日最多的是福州站,霾日数最多的是福清站;福州区域40年来雾日数有减少趋势,而轻雾和霾日数有增多趋势,对比前后20年的雾霾日数分布,福清、福州、闽侯3个站的霾日数出现异常增多;雾日数和霾日数具有明显的季节性变化,雾主要出现在12月~翌年6月的冬春季节,霾主要出现在10月~翌年4月的秋冬春季节,轻雾日数的季节性变化不明显。 相似文献
10.
《防灾科技学院学报》2019,(4)
民国时期辽宁水旱灾害发生频繁,分析其时空分布对深入了解水旱灾害的概况及有效防灾减灾意义重大。通过对民国时期辽宁水旱灾害史料的统计分析,发现民国时期辽宁水旱灾害频发,几乎年年有灾,甚至许多年份两灾并发;水旱灾害的时间分布呈现不平衡性,主要集中于春夏两季,水灾多发于夏季,旱灾则多发于春季;旱灾的持续时间与水灾相比更具连续性,但水灾的波及地域较旱灾更具广泛性;水旱灾害的地区分布具有明显的区域性,水灾多发于辽中地区,旱灾则多发于辽西地区。 相似文献
11.
Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa
and mustard in hydroponic culture 总被引:6,自引:0,他引:6
Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth. 相似文献
12.
The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidizing of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅶ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ). 相似文献
13.
Chlorobenzenes in waterweeds from the Xijiang River (Guangdong section) of the Pearl River 总被引:3,自引:0,他引:3
The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County < Yunan County <Yun'an County < Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River. 相似文献
14.
Degradation of 2,4-dichlorophenol(2,4-DCP)was studied in a novel three-electrode photoelectrocatalytic(PEC)integrative oxidation process,and the factors influencing the degradation rate,such as applied current,flow speed of O_2,pH,adscititious voltage and initial 2,4-DCP concentration were investigated and optimized.H_2O_2 was produced nearby cathode and Fe~(2 )continuously generated from Fe anode in solution when current and O_2 were applied,so,main reactions,H_2O_2-assisted TiO_2 PEC oxidation and E-Fenton reaction,occurred during degradation of 2,4-DCP in this integrative system.The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process,while it was only 31% in E-Fenton process and 46% in H_2O_2-assisted TiO_2 PEC process.So,it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect.By the investigation of pH,it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9. 相似文献
15.
LIU Ting-feng SUN Cheng TA N HONG Jun YANG Shao-gui CHEN Chuan-xiang 《环境科学学报(英文版)》2007,19(10):1235-1238
The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers. 相似文献
16.
The effects of arsenic(As)were investigated on seed germination,root and shoot length and their biomass and some other factors to elucidate the toxicity of As.The results showed low concentrations of As(O-1 mg/kg)stimulated seed germination and the growth of root and shoot,however,these factors all decreased gradually at high concentrations of As(5-20 mg/kg).The contents Of O2-,MDA,soluble protein and peroxidase(POD)activity all increased with increasing As concentrations.Soluble sugar content,ascorbate peroxidase(APX),and superoxide dismutase(SOD)activities decreased at low concentrations of As,and increased at high concentrations of As.While acetylsalicylic acid(ASA)and chlorophyll contents,catalase(CAT)activity displayed increasing trend when the concentrations of As was lower than 1 mg/kg,and then decreasing trend.By polyacrylamide gel electrophoresis(PAGE).As induced the expression of POD isozymes of wheat seedlings.As induced the expression of CAT isozymes but inhibited the expression of SOD isozymes of wheat seedlings at concentrations lower than 1 mg/kg.However,As inhibited the expression of CAT isozymes but induced the expression of SOD isozymes at concentrations higher than 5 mg/kg.The results indicated As could exert harmfulness in the early development stage of wheat at inappropriate concentrations. 相似文献
17.
Polychlorinated biphenyls (PCBs) in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor 1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors (BCFs) of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgKow relationship. The relationship between lgBCFs and lgKow followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgKow, suggesting that a metabolism of the higher Kow PCB congeners occurred. These results support the author's conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners. 相似文献
18.
Andrew Warren 《环境科学学报(英文版)》2007,19(4):470-474
This article explores the assessment of sustainability in fields subject to wind erosion. In the first part, simple sustainability audits are examined, as of soil depth and nutrients. Direct measurement of these characteristics has many problems, largely because of huge variability in space and time at all scales. Modelling still has its problems, but it may be possible to overcome many of them soon. It is true that wind erosion preferentially removes soil nutrients, but there are imponderables even here. The nutrient balance in many of these soils includes considerable input from dust. In West Africa, it has been shown that the amounts of calcium and potassium that are added in dust are sufficient to fertilize dispersed crops. In mildly acidic sandy soils, such as those found on the widespread palaeo- aeolian deposits, much of the phosphorus is fixed and unavailable to plants by the time it is removed by wind erosion, so that erosion has no added downside. Most of the nutrients carried by dust have been shown to travel close to the ground (even when they are attached to dust-sized particles), and so are trapped in nearby fallow strips, and are thus not lost to the farming system. Second, the sustalnabillty of a whole semi-arid farming system is explored. Wind erosion in semi-arid areas (like China, the Sahel and Norflawestern Europe) generally takes place on aeolian deposits of the recent geological past. Most of these soils are deep enough to withstand centuries of wind erosion before they are totally lost to production, and some of these soils have greater fertility at greater depth (so that wind erosion may even improve the soil). Finally some remarks are made about environmental change in relation to sustainability. 相似文献
19.
CAI Peng HUANG Qiao-yun LU Yan-du CHEN Wen-li JIANG Dai-hu LIANG Wei 《环境科学学报(英文版)》2007,19(11):1326-1329
Polymerase chain reaction(PCR)was used to amplify a 600-base pair(bp)sequence of plasmid pGEX-2T DNA bound on soil colloidal particles from Brown soil(Alfisol)and Red soil(Ultisol),and three different minerals(goethite,kaolinite,montmorillonite). DNA bound on soil colloids,kaolinite,and montmorillonite was not amplified when the complexes were used directly but amplification occurred when the soil colloid or kaolinite-DNA complex was diluted,10- and 20-fold.The montmorillonite-DNA complex required at least 100-fold dilution before amplification could be detected.DNA bound on goethile was amplified irrespective of whether the complex was used directly,or diluted 10- and 20-fold.The amplification of mineral-bound plasmid DNA by PCR is,therefore,markedly influenced by the type and concentration of minerals used.This information is of fundamental importance to soil molecular microbial ecology with particular reference to monitoring the fate of genetically engineered microorganisms and their recombinant DNA in soil environments. 相似文献
20.
HUANG Ze-chun AN Zhi-zhuang CHEN Tong-bin LEI Mei XIAO Xi-yuan LIAO Xiao-yong 《环境科学学报(英文版)》2007,19(6):714-718
In order to understand the similarity or difference of inorganic As species uptake and transport related to phosphorus in As-hyperaccumulator, uptake and transport of arsenate (As(Ⅴ)) and arsenite (As(Ⅲ)) were studied using Pteris vittata L. under sand culture. Higher concentrations of phosphate were found to inhibit accumulation of arsenate and arsenite in the fronds of P. vittata. The reduction in As accumulation was greater in old fronds than in young fronds, and relatively weak in root and rhizome. Moderate increases, from 0.05 to 0.3 mmol/L, in phosphate reduced uptake of As(Ⅲ) more than As(Ⅴ), while the reverse was observed at high concentrations of phosphate (≥ 1.0 mmol/L). Phosphate apparently reduced As transport and the proportion of As accumulated in fronds of P. vittata when As was supplied as As(Ⅴ). It may in part be due to competition between phosphorus and As(Ⅴ) during transport. In contrast, phosphate had a much smaller effect on As transport when the As was supplied as As(Ⅲ). Therefore, the results from present experiments indicates that a higher concentration of phosphate suppressed As accumulation and transport in P. vittata, especially in the fronds, when exposure to As(Ⅴ); but the suppression of phosphate to As transport in the root or rhizome may be insignificant when P. vittata when exposure to As(Ⅲ) under sand culture conditions. The finding will help to understand the interaction of P and As during their uptake process in P. vittata. 相似文献