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91.
0前言中国是一个多地震国家,频繁而严重的地震灾害给人民生命和财产带来了巨大的损失,防震减灾任务任重而道远。回良玉副总理2004年在全国防震减灾工作会议讲话中指出:“防震减灾是全社会共同的责任,要广泛动员社会各方的力量,积极投入到这项事业中来,使防震减灾逐步成为全社会的自觉行动。”因此,总结近40年我国防震减灾工作和改革开放的实践经验,对社会公众进行各种防震减灾宣传教育,广泛动员全社会力量,建立健全防震减灾社会动员机制,增强全社会防震减灾意识,是提高我国综合防震减灾能力,有效地促进地震灾害综合防御各项措施落实的重要途… 相似文献
92.
Refining the pre-industrial atmospheric Pb isotope evolution curve in Europe using an 8000 year old peat core from NW Spain 总被引:1,自引:0,他引:1
M.E. Kylander D.J. Weiss A. Martínez Cortízas R. Garcia-Sanchez 《Earth and Planetary Science Letters》2005,240(2):467-485
Pb pollution has existed for several millennia and remains relevant today. By using peat cores as environmental archives it is possible to reconstruct this long history on a regional scale. This is a significant contribution to the findings from ice core records, the only other archive recording purely atmospheric additions. Without information that allows linking and comparison between sites regionally, within Europe and elsewhere, our ability to make coherent global models of the natural Pb cycle, and anthropogenic forcing of this cycle, is limited. In this respect, the characteristics of the Pb pre-pollution aerosol (PPA) are important to define globally. We characterize for the first time a PPA in Southern Europe with [Pb] = 0.78 ± 0.86 μg g− 1, net Pb accumulation rates of 0.032 ± 0.030 mg m− 2 y− 1 and a 206Pb / 207Pb signature of 1.25470 ± 0.02575. This PPA Pb isotope signature is more radiogenic than that found thus far in Western and Northern Europe. Spain is a historically important mining site. Using three-isotope plots and a pool of potential Pb isotope signatures, a detailed source appointment of both natural and anthropogenic Pb sources was made. We found evidence of Saharan aridification and its termination ∼4400 BP and/or agricultural signals and strong local control (from rock and soil) of the Pb PPA. Human impact is first recorded at 3210 BP but does not exceed 50% of deposited Pb until 3005 BP. Mines in SE Spain dominate early Pb pollution history at this site. During the rise of Roman rule, contributions come from mines in N, NW and SW Spain with no strong indication of other European mining activities. In Medieval and Industrial times local contributions to the peat bog are reduced. 相似文献
93.
With the acceleration of industrialization, coal- burning atmospheric pollution is getting more and more serious in many regions in China. However, there are only about ten odd years literature records about pollution in some large and mid-sized cities, where the atmosphere has perhaps been polluted for several decades, and therefore it is difficult to know the process and characteristic of pollution, and diffi-cult to evaluate its damage to environment. Lacustrine sediment, a natural record w… 相似文献
94.
A Possible Detection of the 26 December 2004 Great Sumatra-Andaman Islands Earthquake with Solution Products of the International GNSS Service 总被引:1,自引:0,他引:1
J. Kouba 《Studia Geophysica et Geodaetica》2005,49(4):463-483
The main goal of this work is to critically review the IGS solution products and Precise Point Positioning (PPP) in order
to demonstrate their potential to contribute to studies of large earthquakes such as the one that devastated Southeast Asia
on December 26th, 2004. In view of a possible detection of the Mw 9.0 Sumatra-Andaman Islands Earthquake of December 26, 2004,
position solutions, ranging from intervals of years to one second, of four International GNSS Service (IGS) stations within
3000 km of the epicenter were examined. The IGS combined, cumulative solution product (IGS04P51), consisting of epoch and
station velocity solutions and based on data spans of several years prior to the earthquake, was used as a reference. Four
IGS combined weekly position solutions (igs04P1301-4), two weeks before and after the earthquake, were utilized for the weekly
solution resolution. PPP static and kinematic solutions with IGS Final combined orbits and clocks were used for the mean daily
and instantaneous 5-min and 1-sec epoch solutions, respectively. The most significant changes, detected by both weekly and
daily solutions occurred in longitude. The nearest IGS station ntus, about 1000 km east of the epicenter, moved westward about
15 mm, while the more distant Indian station iisc (∼ 2300 km NW from the epicenter), shifted about 15 mm eastward. In spite
of position errors caused by interpolation of the 5-min IGS clocks, the 1-sec solutions, based on separate data sets, available
only for two stations (iisc, dgar), still showed seismic surface waves, in particular at the Indian station iisc. Precise
daily IGS combined polar motion and length-of-day products, after correcting for the atmospheric effects, also likely detected,
statistically significant, anomalistic excitations on December 26, 2004 that could be caused by this great earthquake. 相似文献
95.
Research relevance, 'knowledge transfer' and the geographies of CASE studentship collaboration 总被引:1,自引:0,他引:1
The Co-operative Awards in Science and Engineering (CASE) studentship programme of the UK Research Councils provide one example of wider efforts internationally to encourage so-called 'knowledge transfer' and thereby harness publicly supported university research more closely to the goals of national competitiveness, regional economic development and local regeneration. In this paper we describe the implications of how the various UK research councils have interpreted the objectives and beneficiaries of 'knowledge transfer', both for the relative opportunities available to human and physical geographers for collaboration through CASE and for the sorts of values that their research must serve. Then, we draw on unpublished data from the Economic and Social Research Council (ESRC) to explore the geographies of CASE studentship allocation and participation. The broad regional and institutional patterns of participation we describe have important implications for ongoing debates in the UK about research selectivity and the role of the university as an engine of local development, while the striking disciplinary patterns of CASE participation, and in particular the overwhelming success of geographers in this competitive programme, provide an opportunity to reassess claims about whether and for whom geographical research is relevant. 相似文献
96.
Zakaria Boujamlaoui Thierry Bariac Philippe Biron Laurent Canale Patricia Richard 《Comptes Rendus Geoscience》2005,337(6):589-598
We seek to identify the depth to which water is extracted by the roots in the soil. Indeed, in an isotopic steady-state condition of leaf water, transpiration introduces into the atmosphere a vapour whose isotopic signature is identical to that of root water. In the isotopic models of atmospheric general circulation, it is classically allowed that the signature of transpiration belongs to the meteoric water line. This supposes that the water taken by the roots has escaped with the evaporation of the soil and comes thus from the deep layers of the soil. At the time of experimentation carried out on maize plants (Nemours, Seine-et-Marne, France), this extraction depth was inferred from the comparison between the signature of the water measured on the level of the first internode of the stems of the plants and the isotopic profile of water in the soil. When the flow of transpiration reaches a maximum value, the plant uptakes water resulting from precipitations and which preserves its non-evaporating character after having quickly infiltrated in the deep layers of the soil. This relates to only 55% of the flux transpired by the canopy, the remainder presenting an evaporating character more or less marked according to ambient conditions. This experiment invalidates the classical hypothesis used in isotopic models of general atmospheric circulation in temperate regions. In fact, only half the amount of water vapour transpired by the canopy during the day presents a signature similar to that of the rainwater sampled in deep soil layers. To cite this article: Z. Boujamlaoui et al., C. R. Geoscience 337 (2005). 相似文献
97.
98.
2003年“雪龙号”北极科学考察期间,对沿途海洋大气进行采样,分析其中气相多环芳烃的空间分布。结果显示,气相中主要是2-4环的多环芳烃,其中菲为主要的化合物,平均占到总多环芳烃的55.1%。在整个航程的广泛区域尺度内,气相总多环芳烃浓度在1043.9-92993.1pg/m3。空间分布上,远东亚的海面>北太平洋海面>北极圈以内海面;总多环芳烃的浓度随纬度升高呈现显著降低的趋势。通过Clausius-Clapeyron方程对浓度和温度相互关系的分析表明,温度是控制气相多环芳烃长距离传输的主要因素。 相似文献
99.
Using stable isotopes to understand seasonal and interannual dynamics in moisture sources and atmospheric circulation in precipitation
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Yu Tang Xianfang Song Yinghua Zhang Dongmei Han Likun Ai Tianbao Zhao Yajun Wang 《水文研究》2017,31(26):4682-4692
Stable isotopes in precipitation are useful tracers to strengthen understanding of climate change and hydrological processes. In this study, the moisture sources of 190 precipitation events in Beijing were analysed using the Hybrid Single‐particle Lagrangian Integrated Trajectory model, based on which we studied the relation between variations in precipitation δ18O and dynamics in moisture sources and atmospheric circulation in seasonal and interannual timescales. Categorization of 7 groups of moisture sources was performed, among which oceanic moisture sources presented lower δ18O in precipitation than continental moisture sources. The results show that seasonal variations of precipitation δ18O were caused by changes of moisture sources. In summer, moisture from proximal oceans dominated vapour transport to Beijing due to increasing monsoon strength and resulted in a relatively small variation of precipitation δ18O. At the interannual timescale, the variations of δ18O in summer precipitation were related to dynamics in oceanic moistures, showing depleted values when the contribution of oceanic moistures, especially the proportion of long‐distance oceanic moisture, was high. Further analysis indicated that changes of oceanic moisture sources were controlled by the strength of summer monsoons. These findings address the complexity of moisture sources in midlatitude monsoon areas and suggest that isotopic signals in precipitation have the potential to deduce changes in moisture sources and atmospheric circulation and can therefore serve for palaeoclimate reconstruction. 相似文献
100.
The impact of boreal autumn SST anomalies over the South Pacific on boreal winter precipitation over East Asia 总被引:1,自引:0,他引:1
The possible mechanism behind the variability in the dipole pattern of boreal winter precipitation over East Asia is analyzed in this study. The results show that the SST anomalies(SSTAs) over the South Pacific Ocean(SPO) in boreal autumn are closely related to the variability in the dipole pattern of boreal winter precipitation over East Asia. The physical link between the boreal autumn SPO SSTAs and the boreal winter East Asian precipitation dipole pattern is shown to mainly be the seasonal persistence of the SPO SSTAs themselves. The seasonal persistence of the SPO SSTAs can memorize and transport the signal of the boreal autumn SSTAs to the following winter, and then stimulates a meridional teleconnection pattern from the SH to the NH, resulting in a meridional dipole pattern of atmospheric circulation over East Asia in boreal winter. As a major influencing factor, this dipole pattern of the atmospheric circulation can finally lead to the anomalous precipitation dipole pattern over East Asia in boreal winter. These observed physical processes are further confirmed in this study through numerical simulation. The evidence from this study, showing the impact of the SPO SSTAs in boreal autumn,not only deepens our understanding of the variability in East Asian boreal winter precipitation, but also provides a potentially useful predictor for precipitation in the region. 相似文献