中国北方春季起沙活动时间序列及其与气候要素的关系

利用1961—2002年春季中国681个站沙尘天气的实测资料,将起沙机理相似的扬沙、沙尘暴通过并集运算进行复合,得到一个新的能体现完整起沙活动的时间序列。统计学检验表明,新序列较单一的沙尘暴序列具有诸多优点。进一步从681个站中筛选出代表性较好的中国北方175个站,探讨了春季起沙活动（DBS）时间序列与冷空气、大风、气温、降水等气候要素的关系。结果表明:①春季DBS与大风日数、冷空气次数的相关系数分别为0.946和0.406。②春季DBS与平均气温、最低气温、最高气温的相关系数分别为-0.494、-0.607和-0.269。③春季降水对DBS的影响主要取决于降水的强度和降水的时间分布,5 mm以上的降水才能有效地抑制DBS的发生。     

我国北方沿海地区地下水库分类及综合对比

我国北方沿海地区具备良好的建库条件,且开发潜力较大。在总结国内外有关地下水库科学管理和研究的基础上,对我国北方沿海地区地下水库进行了分类,并对不同类型地下水库的建设条件进行了综合对比。通过对水资源的时空优化配置和联合调度,实行地下水库科学管理,将有效改良土壤和水质,防治海水入侵,改善库区生态水文环境,实现沿海地区有限淡水资源的长期有效利用。     

1920年中国北方7省（市）大旱的灾情及其成因

分析了1920年中国北方7省（市）大旱的旱情及其形成的物理因素。结果表明：1920年中国北方的大旱灾以京津冀最为严重,范围大,且多灾并发,危害异常严重。从1918年夏季到1920年春季南方涛动指数为负位相,是此次大旱重要的热带环流年际变化背景;该年是近百年来西太平洋副热带高压最弱最偏东的一年,这是形成大旱的主要原因;强厄尔尼诺事件是大旱的重要原因;登陆台风偏少和台风位置偏东、偏南,是造成干旱的原因之一。     

我国北方气旋的天气气候分析

本文利用1949—1988年的资料,分析了我国北方气旋的若干气候特征,讨论了这些特征与大气环流演变和特殊地形作用的密切关系。可供业务预报和科研工作参考。     

Seasonal variation in soil microbial biomass carbon and nitrogen in an artificial sand-binding vegetation area in Shapotou, northern China

In this study, seasonal variation characteristics of surface soil microbial biomass carbon （MBC） and soil microbial biomass nitrogen （MBN） of an artificial vegetation area located in Shapotou for different time periods were studied using the chloroform fumigation method, and the results were compared with those of near-natural vegetation areas and mobile dunes. Results showed that the MBC and MBN levels in the 0-5 cm soil layer were higher in autumn than in summer and spring. As the prolongation of vegetation restoration raised the MBC and MBN levels in summer and autumn, no clear variation was found in spring. However, the MBC and MBN in 5-20 cm had no obvious seasonal variation. During summer and autumn, the variation trend of MBC and MBN in the vertical direction was shown to be 0-5 〉 5-10 〉 10-20 cm in the vegetation area, while for mobile dunes, the MBC and MBN levels increased as the depth increased. The natural vegetation area was shown to possess the highest MBC and MBN levels, and yet mobile dunes have the lowest MBC and MBN levels. MBC and MBN levels in artificial sand-binding vegetation increased with the prolongation of vegetation restoration, indicating that the succession of sand-binding vegetation will result in the ac- cumulation of soil carbon and nitrogen, as well as the restoration of soil fertility.     

冬季观测流星雨小提示

地点选择观测流星雨一般选择远离城市光污染、海拔高、地形开阔、周边遮挡少的地方。城市郊区的农家院是不错的选择,相对也安全一些。北方冬季需要考虑下雪后开车安全问题。保暖措施观测流星雨,最容易被忽视的是保暖问题,冬季更是如此。经常见到有天文同好衣服准备不足,刚开始半小时还没问题,但下半夜无法坚持观测,错过最精彩的场景。     

Fossils of Macaca mulatta from Tianyuan Cave,with Notes on Some Previously Unpublished Specimens of Macaca from Zhoukoudian Area

The recently discovered macaque fossils, including isolated teeth and mandible fragments, from Tianyuan Cave and the juvenile maxilla from Wanglaopu Cave near Zhoukoudian can be identified as Macaca mulatta; they represent the first recognized occurrence of fossil M. mulatta in the far north of China. Some previously unearthed but still unpublished Macaca specimens were also studied, including a cranium and the associated mandible from CKT Loc.13A, a maxilla and a mandible from Loc.1, a mandible from Loc.4, and a maxilla from Loc.20, as well as a mandible with complete toothrow from Zhoukoudian but without locality details, all of them can be referred to M. robusta. The study shows M. robusta is more closely related to M. mulatta than to M. anderssonL Zhoukoudian is the richest area of Macacina fossils in North China, totally 2 genera and 4 species were once recognized from 9 localities, namely, Procynocephalus wimani, M. cf. anderssoni, M. robusta and M. mulatta. The fossil records of Macacina in Zhoukoudian area were almost continuous through the Quaternary Period, and it＇s reasonable to assume that Zhoukoudian used to be an evolutionary center for macaques in North China. Therefore, the macaque population of M. mulatta once existed decades ago around Beijing probably originated from the Pleistocene ancestors in the local area, rather than being human-introduced as previously thought.     

论俄罗斯北方航道治理路径及前景评估

随着气候变暖及融冰加剧,近年来北极问题的影响逐步扩散,北方航道的预期经济性也引发关于大规模开发利用的讨论。在内外需求交织的背景下,俄罗斯以"有限开放"原则为基础采取"选择性妥协"治理路径,在航行规则和基础设施建设等问题上主动妥协,努力将北方航道作为应对外部挑战和国内发展需求的新增长点。北方航道有限的数据背后反映出航运需求和经济性预期的片面性,且缺乏对自然条件、航运安全、污染防控等多重不确定因素评估,在短期内尚不具备大规模商业通航和投资的条件。以季节性运输及试航积累冰区航行经验,以港口基建为路径配置资金技术输出,以航运企业为主体主动配合俄罗斯战略调整需求,或是我国参与北方航道事务的优选方案。     

南方强对流天气频发 北方旱情持续发展——2007年4月——

4月，全国平均气温为11．1℃，比常年同期偏高0．912。月内气温起伏变化较大，上旬，我国中东部地区气温较常年同期偏低或接近常年；中旬，全国大部分地区气温较常年同期偏高；下旬，南方和西北中东部地区气温偏低，北方大部分地区气温偏高或接近常年同期。全国平均月降水量为41．2mm，较常年同期略偏少。与常年同期相比，华北大部、黄淮、西北东部及南疆等地月降水量偏少，西北中北部及云南、西藏大部等地降水偏多。     

基于遥感技术的中国北方沙质荒漠化防治建议

根据中国北方地区人类活动对地表组成物质的扰动特征,将中国北方沙质荒漠化土地治理区划分为绿洲周缘农业型沙质荒漠化、农牧交错带农牧型沙质荒漠化、草原牧业型沙质荒漠化三种类型;利用1975年M SS卫星图像数据和2000年ETM卫星图像数据为信息源,在M APG IS软件支持下,采用人机交互方法对沙质荒漠化土地类型进行信息提取,编制研究区1975年和2000年沙质荒漠化土地类型分布图,在根据沙质荒漠化土地类型的变化幅度确定沙质荒漠化土地变化类型的基础上,通过1975年和2000年沙质荒漠化土地类型分布图的叠加分析,查明了中国北方近25年来沙质荒漠化土地的时空演化规律,结合中国北方不同沙质荒漠化土地治理区的自然条件和人类活动特征,提出了中国北方沙质荒漠化土地治理建议。