降水与氮沉降变化对草地关键氮过程的影响研究进展

研究降水格局变化和氮沉降增加对草地氮循环关键过程的影响,探索不同氮循环过程对未来全球气候变化的叠加效应和适应特征,为最终调节氮素转化过程,提高草地氮素利用效率并降低其生态环境负效应提供科学依据.本文综述了不同水分、氮素以及水氮耦合作用分别对植物氮库、土壤氮库的影响,同时分析了在这些条件变化下可能存在的微生物和酶活性变化的驱动机制.在此基础上探讨了水、氮变化对草地氮循环关键过程影响的不确定性以及目前研究中存在的主要问题.     

青海湖地区草地蝗虫发生的气候背景

气候条件对环青海湖地区草地蝗虫的发生程度有重要影响。上一年的下半年气温偏低和当年高温干旱 ,是蝗虫发生的有利气候条件 ;上一年的 8月份、当年 5月下旬到 7月上旬以及当年 8月份的气候条件与蝗虫发生程度密切相关。     

ENSO对我国江南及印度降水影响的比较

根据近百年我国江南和印度的降水资料,对比分析了其各季降水与ＥＮＳＯ的关系。统计表明,Ｅ１Ｎｉｎｏ发生时印度夏季和秋季降水的减少最显著,分别比多年平均减少４．５％和６．０％,Ｌａ Ｎｉｎａ时则分别增加６．６％和８．１％。对我国江南降水影响最显著的是冬季,在Ｅ１ Ｎｉｎｏ事件时降水比多年平均偏多１８．５％,Ｌａ Ｎｉｎａ时则偏低了１７．７％。降水的年代际变化可以影响ＥＮＳＯ与降水的关系。９０年代江南处     

近43年来小兴安岭及周边地区的气候变化特征

利用黑龙江省的逐日气象资料,对过去43年中的小兴安岭及周边地区的气候变化特征进行了分析,并与黑龙江全省的情况进行了比较.结果表明:该地区的气候变化特征与黑龙江全省基本一致,气候特征的季节性变化比较明显,同时小兴安岭地区的气候变化对周边地区产生了一定的影响.全省范围内气温均呈变暖趋势,小兴安岭最低气温的升高对其周边地区有一定的拉动作用全省以及小兴安岭及其周边地区年降水量出现较大波动的同时,降水越来越集中,且小兴安岭及其周边地区的水分条件要好于全省的平均水平.     

Public concerns and the public role in siting nuclear and chemical waste facilities

Nuclear and chemical waste facilities can be successfully sited, despitenimby responses, if siting programs account for the sources of public concern. Irrational fear is not the main source; instead, waste managers must deal with perceived inequities in the distribution of benefits and costs, and concern about facility safety. Benefit-cost inequities may be dealt with in part by keeping wastes where they are generated, through political restrictions, or by providing economic compensation and political incentives (for example, a local veto). Assuring people of facility safety includes allowing local control (monitoring, health assessment, regulation), and enhancing trust of facility managers through such means as rectifying past mistakes, individual-oriented education campaigns, and negotiation of compensation packages with local residents. These means should reduce —without eliminating—public opposition to local siting of nuclear and chemical waste facilities.     

PRECIPITATION DISTRIBUTION IN COASTAL BRITISH COLUMBIA1

ABSTRACT: The spatial distribution and the temporal and spatial variation of the annual, seasonal, and monthly precipitation in two mountainous watersheds in southwestern British Columbia, Canada, have been analyzed using a detailed database for 1971–1990 in the Capilano and Seymour watersheds. The analysis showed that the precipitation increases up to the mid-position of the watersheds, and then either levels off or decreases. Precipitation on mountain slopes and in the valley at the same distance from the beginning of the slope is similar, and the barrier height is identified as the dominant parameter which influences the precipitation distribution. The temporal variation of the precipitation is the smallest at the mid-position of the watersheds. This variability is the least in the fall and winter and largest in the summer. Correlation between the precipitation accumulations at various stations is large, ranging from 0.80 for the wet period of October-March to 0.65 for the dry period of April-September for distances less than 32 km. Comparison with other studies and the analyses of precipitation and runoff data from coastal British Columbia showed that the results of this study are perhaps general and thus transferable to similar areas in the coastal Pacific Northwest.     

PRECIPITATION AUGMENTATION-PROBLEMS AND PROGRESS1

ABSTRACT: Advances in the science of weather modification have provided an opportunity for significant progress in the area of precipitation management. Coordination of efforts and intensification of both laboratory and field research could lead to major advances within the decade. In view of the important decision-making role played by society, however, it is necessary that our scientific efforts be coordinated with a public relations program designed to inform and educate the public on the role and potential of artificial precipitation augmentation. In addition, careful consideration must be given to those social and legal issues related to weather modification. Environmental impact, land use, economic potential and damage liability are aU factors of importance in any comprehensive analysis. Rational solutions to questions in each of these areas is dependent upon the establishment of a sound scientific basis for operational weather modification, which should be the first priority.     

降水中离子浓度与pH值的确定性相关关系研究

关于降水中离子浓度与pH值关系问题的研究多是基于降水化学数据的统计分析。从酸碱平衡理论出发 ,在电中性方程的基础上 ,建立了降水中离子浓度与pH值的确定性相关关系式。结果表明 ,该式具有普适性 ,是反映多种离子综合作用的重要参数。用公式对 50组降水化学数据做了计算分析 ,结果表明 ,降水离子浓度与 pH值的关系研究应考虑足够多的离子种类 ,降水化学数据也应满足 :( 1 )离子平衡值等于或接近 1 .0 ;( 2 )ΔC的正负号与 pH值范围的关系协调一致。可作为降水化学数据是否准确、合理的判据     

离子色谱法对阴离子分析方法的探讨

通过选择放大倍数、确定样品稀释倍数、加标回收等不同条件,运用离子色谱法对降水、饮用水、地表水中的F-,CL-,NO-2,NO-3加4进行了大量的实验分析。方法具有良好的线性(相关系数在0.9991～0.9997)和重复性(相对标准偏差小于1.9%),NO-3,SO2-标平均回收率为98.6%。方法简便实用,用于实际样品分析,所得结果令人满意。     

重庆大气中TSP和自然干沉降的化学组成及其浓度贡献

本文分别对重庆大气颗粒物中TSP、自然干沉降的化学组成及其浓度水平进行了阐述.Ca元素在TSP中位居第一.而Fe元素在干沉降中位居第一.