西北太平洋热带气旋气候变化的若干研究进展

热带气旋气候变化研究不仅是当前国际热带气旋气候界的热点科学问题,而且也是具有现实意义的社会问题,各国气象学者和科学家们对此进行了广泛的研究。虽然热带气旋活动与气候变化之间的关系及其相应的内在物理机制至今还处在探究之中,但是近20多年来热带气旋气候学的研究还是取得了显著的进展。本文主要针对濒临中国的西北太平洋海域,回顾了热带气旋活动季节内、年际、年代际变化及其全球变暖背景下的变化趋势的气候学研究。此外,文中也对西北太平洋热带气旋气候学的研究进行了展望,并提出了该领域中一些亟待解决的科学问题。     

1：50000数据库的更新服务数据库系统设计与实现

1：50000数据库的更新工程数据库服务系统是以1：50000数据库更新成果为基础．建立了一个基于B／S结构的服务系统,满足更新数据快速发布、浏览、应急服务等需求。本文介绍了陔系统的设计思想、系统总体架构、数据库设计与建库、软件功能设计与实现,为其他地理信息数据系统建设提供借豁。     

Geographical patterns of tree-limits of Norway spruce and Scots pine in the southern Swedish Scandes

The tree-limit altitudes of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) from 180 sites (within an area of 95?km?×?165?km) in the southern Scandes were correlated with the geographical variables latitude, longitude and distance to the sea. The results were compared with a similar investigation of the tree-limit of mountain birch (Betula pubescens Ehrh. ssp. tortuosa (Ledeb.) Nyman) in the same area. The three tree-limit altitudes showed good negative correlation with latitude, poor correlation with longitude and good positive correlation with the distance to the sea, suggesting that on a regional scale the altitudes are controlled by macroclimate. At some sites, local topoclimatic features, some of which were partially aspect-dependent, may cause deviations in the regional pattern of tree-limit altitude that is set primarily by summer temperature. Tree-limit responses to potential future climate warming will probably differ substantially in magnitude from site to site in relation to local topography and associated ecological constraints.     

基于球面DQG的矢量与地形数据无缝集成

现有的全球大规模空间数据可视化系统主要侧重于影像和地形数据的综合表达,针对矢量与地形的集成可视化能力相对较弱。该文以球面退化四叉树格网(Degenerate Quad-tree Grids,DQG)为基础,通过DQG格网的三角化过程构建了地表DEM模型,并提出了从矢量线对象到地形格网表面的映射方法。采用GTOPO30数据集和国界矢量数据进行了相关实验,结果表明:该方法能实现矢量数据与多分辨率DEM的无缝集成,并能有效地避免矢量对象"悬浮"和"入地"等现象。     

三个全球气象灾害数据库对比及展望

针对气象相关灾害,对3个主要全球灾害数据库进行了概述,包括比利时鲁汶大学国家灾害流行病研究中心的紧急灾害数据库(EM-DAT)、德国慕尼黑再保险公司的自然灾害数据库(NatCat)和瑞士再保险公司的数据库(Sigma),比较了各灾害数据库在建设目的、收录标准及灾害种类划分上的差异.E M-D AT由于能够访问下载,在国...     

Cloud radiative forcing of subtropical low level clouds in global models

Simulations of subtropical marine low clouds and their radiative properties by nine coupled ocean-atmosphere climate models participating in the fourth assesment report (AR4) of the intergovernmental panel on climate change (IPCC) are analyzed. Satellite observations of cloudiness and radiative fluxes at the top of the atmosphere (TOA) are utilized for comparison. The analysis is confined to the marine subtropics in an attempt to isolate low cloudiness from tropical convective systems. All analyzed models have a negative bias in the low cloud fraction (model mean bias of −15%). On the other hand, the models show an excess of cloud radiative cooling in the region (model mean excess of 13 W m⁻²). The latter bias is shown to mainly originate from too much shortwave reflection by the models clouds rather than biases in the clear-sky fluxes. These results confirm earlier studies, thus no major progress in simulating the marine subtropical clouds is noted. As a consequence of the combination of these two biases, this study suggests that all investigated models are likely to overestimate the radiative response to changes in low level subtropical cloudiness.     

Making local futures tangible—Synthesizing, downscaling, and visualizing climate change scenarios for participatory capacity building

Local in its causes and global in its impacts, climate change still poses an unresolved challenge for scientists, politicians, entrepreneurs, and citizens. Climate change research is largely global in focus, aims at enhanced understanding, and is driven by experts, all of which seem to be insufficient to anchor climate change action in regional and local contexts. We present results from a participatory scenario study conducted in collaboration with the municipality of Delta in SW British Columbia, Canada. This study applies a participatory capacity building approach for climate change action at the local level where the sources of emissions and the mechanisms of adaptation reside and where climate change is meaningful to decision-makers and stakeholders alike. The multi-scale scenario approach consists of synthesizing global climate change scenarios, downscaling them to the regional and local level, and finally visualizing alternative climate scenarios out to 2100 in 3D views of familiar, local places. We critically discuss the scenarios produced and the strengths and weaknesses of the approach applied.     

全球变暖背景下江淮地区降水强度分布结构变化的特征分析

利用1961～2006年江淮地区80个站点的逐日降水资料,根据百分位数确定极端降水阈值的方法,比较了全球气候变暖背景下该区域降水强度的分布结构特征。结果表明,在全球气候典型暖异常的年份里,江淮地区极端降水日数占总降水日数的比重比冷年增加30%以上,极端降水总量的比重增加13%左右;而微量降水日数所占比重比冷年减少近60%,微量降水总量减少了80%,说明全球变暖后江淮地区降水强度分布结构呈现弱降水减少,强降水增多的显著两极分化特征,且该特征在江淮地区基本一致。冬、夏季对比表明,冬季的变化幅度比全年和夏季更大。可见全球变暖背景下未来江淮地区降水强度分布结构出现两极分化趋势可能性增加。     

Comparison of global storm activity rate calculated from Schumann resonance background components to electric field intensity E0Z

This work presents the results of a comparison between the global storm activity rate I_RS and electric field intensity E_0Z. The permanent analysis of the I_RS may become an important tool for testing Global Electric Circuit models. I_RS is determined by a new method that uses the background component of the first 7 Schumann resonances (SR). The rate calculations are based on ELF observations carried out in 2005 and 2006 in the observatory station “Hylaty” of the Jagiellonian University in the Eastern Carpathians (Kułak, A., Zięba, S., Micek, S., Nieckarz, Z., 2003. Solar variations in extremely low frequency propagation parameters: I. A two-dimensional telegraph equation (TDTE) model of ELF propagation and fundamental parameters of Schumann resonances, J. Geophys. Res., 108, 1270, doi:10.1029/2002JA009304). Diurnal runs of the I_RS rate were compared with diurnal runs of E_0Z amplitudes registered at the Earth's surface in the Geophysical Observatory of the Polish Academy of Sciences in Świder (Kubicki, M., 2005. Results of Atmospheric Electricity and Meteorological Observations, S. Kalinowski Geophysical Observatory at Świder 2004, Pub. Inst. Geophysics Polish Academy of Sciences, D-68 (383), Warszawa.). The days with the highest values of the correlation coefficient (R) between amplitudes of both observed parameters characterizing atmosphere electric activity are shown. The seasonal changes of R, I_RS and E_0Z are also presented.     

Modeling the electric structures of two thunderstorms and their contributions to the global circuit

This study examines the electricity in two thunderstorms, typical for their respective locales (the Great Plains and the New Mexico mountains), by modeling them as a set of steady-state horizontal layers of external currents. The model electric sources, corresponding to the charge separation processes in the thundercloud, are embedded in an exponential conducting atmosphere. The source parameters are determined by fitting the model electric field to measured profiles. The resulting currents to the ionosphere (i.e., the Wilson current) from the two storms are 0.53 A and 0.16 A, while the calculated electrical energies of the storms are 2.3 × 10¹⁰ J and 2.8 × 10⁹ J, respectively. The more vigorous storm is estimated to transfer 16 000 C in the global circuit during 8.5 h of its lifetime, while the weaker mountain storm transferred about 1200 C in its entire 2-h lifetime. Removal of the screening charge layer from above the updraft region in one modeled storm leads to only a small increase in the net Wilson current of less than 3%, while it provides a substantial local disturbance of the electric field. Overall, the model findings indicate that differences in the Wilson currents and electrical energies of the two storms result from differences in their internal dynamical and electrical structures as well as their geographical locations.