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?????鳣???????????????????????е???????????????Trimble R8 GNSS/RTK??TCA2003?????????????????????????????SPRINTER 200M?????????????????????????????????0.5 Hz????????????????????????????????FFT?????????????????????????????????????????ж????????????????TCA2003???????????????????????????????????SPRINTER 200M????????????????????仯?????????????г???GNSS/RTK????????????г???     

1951-2007年华北地区夏季气温变化特征

利用1951—2007年月平均气温资料和NCEP/NCAR1951年1月—2007年12月500 hPa高度场再分析资料,统计近57 a华北地区29个台站逐年夏季气温值,运用EOF、REOF、趋势分析、Morlet小波分析、M-K突变检验及相关分析等对华北夏季气温的时空分布及其成因进行分析。结果表明：近57 a华北地区29站平均气温的空间差异较大;一致性特征是华北地区夏季气温的最主要的空间模态,在此基础上,第2种空间模态还显示出了华北地区夏季气温的南北差异;华北地区夏季气温可分为环渤海型、南方型、东北型及西部型4个主要的空间分型;近57 a来华北地区夏季气温各分区的周期振荡不完全一致,但都存在着一个准18 a的周期;20世纪90年代前中期,华北地区除Ⅱ区外,其他三区都存在着一个突变点,在突变点之后,出现了5个气温大值年,即酷暑年。我国华北地区夏季酷暑成因：从500hPa环流场来看,在欧亚中高纬地区,存在显著的正负距平相间的波列,其中最大正距平中心位于蒙古地区,说明东亚中纬度地区西风带位势高度场异常偏高,有利于引导西太平洋副热带高压北上,造成华北夏季气温升高;从我国华北地区汛期降水距平场来看,汛期降水偏少,也会导致华北夏季的酷暑天气。     

1980—1989年全球1000 hPa高度距平3—5年尺度演变

80年代发生了两次较强的El Ni?o事件。本文利用 ECMWF的月平均资料，分析了1980—1989年期间1000 hPa高度距平3—5年尺度的全球演变特征。发现了南北半球主要正负距平的演变既有驻波特征，又有传播波特征。南半球正负距平的变化与南方涛动相联系，而北半球正负距平的变化与北方涛动相联系。二者既互相独立，又互相配合。它们在80年代两次ENSO过程的演变中都起着重要作用。特别是1982／1983和1986／1987年El Ni?o事件发生前，分别有明显负距平沿南、北太平洋副热带自西部移向东部，使南     

Double station and spectroscopic observations of the Quadrantid meteor shower and the implications for its parent body

Object 2003 EH₁ was recently identified as the parent body of the Quadrantid meteor shower. The origin of this body is still uncertain. We use data on 51 Quadrantid meteors obtained from double-station video observations as an insight on the parent body properties. A data analysis shows that the Quadrantids are similar to other meteor showers of cometary origin in some aspects, but in others to Geminid meteors. Quadrantid meteoroids have partially lost volatile component, but are not depleted to the same extent as Geminid meteoroids. In consideration of the orbital history of 2003 EH₁, these results lead us to the conclusion that the parent body is a dormant comet.     

THE CORE OF THE QUADRANTID METEOROID STREAM IS TWO HUNDRED YEARS OLD

The Quadrantids are one of the most active annual meteor showers and have a number of unusual features. One is a sharp brief maximum, 12–14 h in length. A second is the Quadrantids, relatively recent appearance in our skies, the first observation having likely been made in 1835. Until recently no likely parent with a similar orbit had been observed and previous investigators concluded that the stream was quite old, with the stream’s recent appearance and sharp peak attributed to a recent fortuitous convergence of meteoroid orbits. The recent discovery of the near-Earth asteroid 2003 EH1 on an orbit very similar to that of the Quadrantids has almost certainly uncovered the parent body of this stream. From the simulations of the orbit of this body and of meteoroids released at intervals from it in the past, we find that both the sharp peak and recent appearance of the Quadrantids can most easily be explained assuming meteoroids were ejected in substantial numbers near 1800 AD.     

Methods for measuring components of radiative-heat balance of the surface and depths of seasonal thawing in the area of Schirmacher Oasis (Antarctica)

This article is based on the results of seasonal field works during 2007–2008 in the area of the Schirmacher Oasis, as well as on the Aerodromnaya (Air Port), Palets (Finger), Nunataki, and Bazisnaya (Base) Mountains near the Novolazarevskaya Station (Antarctica). The methods used to perform research on the components of the radiative-heat balance of the surface, thermal conductivity, and depths of seasonal thawing are discussed.     

中国中部六省预期寿命时序加密估算研究

年龄组死亡率是利用年龄分组人口数据计算预期寿命的关键参数,而非采样年份的统计年鉴中年龄分组死亡率缺失导致无法计算预期寿命。针对该问题,本文将人口普查数据与统计年鉴数据融合,首次提出一种基于拉格朗日插值的中国省级预期寿命时间序列加强密集度（时序加密）的算法,以解决非采样（即未进行人口普查或1%人口抽样调查）年份省级预期寿命的估算问题。以中国中部六省为例,在所选取年份省级预期寿命估算实验中,绝对精度表明年龄分组人口比例线性插值计算的精度明显高于人口比例抛物线插值和直接插值算法的精度,故为推荐算法。本研究为高时间分辨率下省级预期寿命值的获取提供了一个新的可行思路,为分省较精确地进行预期寿命趋势分析奠定基础。     

El Nino衰减年西北太平洋热带气旋活动特征的差异性北大核心

El Nino衰减年西北太平洋热带气旋(Tropical cyclone,TC)活动表现出多样性,给TC活动的气候预测带来挑战。采用美国联合台风预警中心的热带气旋最佳路径数据和欧洲中期预报中心提供的ERA-5再分析资料,对1970—2018年的El Nino衰减年7—10月的西北太平洋TC生成频数进行合成分析,发现其与气候态没有显著的差异,但在单个年份,存在着较大的正、负异常。为此,将El Nino衰减年分为TC生成频数偏少(负异常)和偏多(正异常)两种情形,对比两种情形的TC活动和大尺度环境要素特征。结果表明,TC生成频数偏少的情形,TC生成频数的异常减少主要发生在西北太平洋东部海域,即(15°~25°N,140°~150°E)和(5°~25°N,150°~170°E),与垂直风切变增大、对流层中层相对湿度和低层绝对涡度减少有关;TC生成频数偏多的情形,TC生成频数的异常增加主要发生在南海和菲律宾群岛附近,即(15°~25°N,110°~120°E)和(5°~25°N,120°~130°E),对流层中层相对湿度增加的贡献最大,其次是上升运动增强和绝对涡度增大;对比两种情形发现,TC生成频数偏多的情形,广东和福建沿岸的东南风异常引导气流有利于菲律宾群岛附近生成的TC登陆中国大陆。     

江淮流域夏半年日照时数气候特征及趋势分析

基于江淮流域逐月日照时数观测资料,利用旋转正交函数(REOF)、线性趋势分析、Mann-Kendall突变检验以及Morlet小波分析等方法,对江淮流域夏半年(5—10月)日照时数进行了统计分析,结果表明:江淮流域夏半年日照时数普遍在1000～1200 h之间,呈现由南向北递增的空间分布特点,但受地形等因素影响又存在区域性差异。同时发现其标准差与平均日照时数呈现并不一致的分布规律。进一步将江淮流域日照时数分为4个区,分别为北部区Ⅰ、东北区Ⅱ、西南区Ⅲ和东南区Ⅳ,每个区都表现出显著的下降趋势,但在线性趋势、突变时段以及周期特征上,各个区域又存在显著的差异。