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全球变化条件下的平流层大气长期变化趋势 总被引：5，自引：0，他引：5
两个因素将对21世纪平流层气候变化产生重要作用。一个是温室气体增加,另一个是平流层臭氧的可能恢复。温室气体增加的辐射效应一方面造成地面和对流层变暖,另一方面却导致平流层变冷,而臭氧层恢复的辐射效应则导致平流层变暖。在温室气体增加和臭氧恢复这两种相反因素作用下的平流层温度如何变化是所关心的主要问题。为了预估平流层温度在21世纪的变化,使用了辐射—对流模式进行了敏感性实验,另外,也对他人进行的化学—气候耦合模式（CCM）模拟结果进行了分析。这些模拟结果表明,在21世纪平流层中上层（60～1 hPa）将变冷,而下层（150～60 hPa）变暖。这说明在平流层中上层温室气体的冷却效应将起主导作用,而臭氧恢复的加热效应在平流层下层相对更为重要。CCM的模拟结果表明,臭氧恢复最显著的区域在平流层上层（3 hPa附近）,与最大降温区一致,说明温室气体增加将有利于平流层上层臭氧恢复。CCM的模拟结果还表明,平流层两极地区在冬半年存在变暖的现象。根据已有的研究结果,极区变暖与平流层行星波活动增强有关,动力、热力和化学之间的正反馈作用也有可能对极区变暖有重要的贡献。 相似文献
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西天山山区气候变化与灌区绿洲气候效应 总被引：10，自引：2，他引：8
对近40a西天山山区气候变化的特点及其变化趋势进行了分析,并以阿克苏源流区、阿克苏灌区以及叶尔羌河灌区的14个气象站的观测资料(1961—2000年)为基础,重点研究了灌区的气候变化及绿洲气候效应.20世纪90年代以来,各区域的气温增高,降水增多,其中在源流地区降水增加幅度最大,而沙尘暴、浮尘和大风日数都有明显的下降.最后,讨论了气候变化与绿洲发展的关系. 相似文献
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全球气候研究计划 (WCRP)中的气候与冰冻圈项目 (CliC): 冰冻圈与气候的优先研究领域 总被引：1，自引：1，他引：0
RogerG.Barry 《冰川冻土》2002,24(5):523-525
The cryosphere is an integral part of the global climate system, however, many aspects of the cryosphere have not been fully covered within WCRP. Issues relating to potential changes in the climate cryosphere system become more and more important in order to describes research and coordination initiatives required to integrate fully studies of impact and response of the cryosphere to climate change. The article also indicates the recent progress of CliC, and its future plan. 相似文献
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Stephanie Hänsel 《Environmental Earth Sciences》2013,69(4):1491-1494
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陆相沉积形成于地圈与水圈、大气圈和生物圈的交界面上,比海相地层更有效地记录了地球表层环境的信息。通过对沉积岩中沉积物的粘土矿物、气候指数、氧同位素测温等研究,获得关于气候干湿冷暖的信息。基于对这些常用方法的研究,提取出一些陆地上的特殊沉积,如：陆相红层、沙漠沉积体系、蒸发岩、煤及油页岩等所包含的丰富气候信息。沙漠代表干旱炎热气候;陆相红层的出现反映高温氧化环境,其在干旱和潮湿的热带气候下都能形成;芒硝代表干冷的气候环境;石膏则代表干热,水体盐度高,蒸发作用强的气候条件;煤层/油页岩一般形成于温暖潮湿的气候环境。对特殊沉积的研究可以用来重建古气候和恢复大陆古环境。 相似文献
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Tyson P. D. 《GeoJournal》1981,2(2):3-10
Short-term changes in the general circulation of the atmosphere, which may lead to prolonged periods of drought, are catalysts for producing accelerated desertification. In southern Africa the northeastward thrust of desertification from the western and central arid and semi-arid areas (the Karoo) has long been recognised, but up til 1970 research failed to demonstrate a clear-cut relationship between the process of desertification and long term rainfall data. The application of sophisticated analytical techniques to regional rainfall data showed, however, that spatial and temporal variations in the Southern African rainfall pattern have a striking degree of organization. The summer rainfall region of the northeastern part of the subcontinent experiences 16–20 year fluctuations, in contrast with 10–12 year fluctuations in the all-season rainfall region along the southern Cape coast. Concentrating on regionally averaged data for the summer rainfall region, the author used Fourier analysis to confirm the persistence of the quasi 20-year fluctuations since 1840. The wet spell of the late 1970s is expected to die out by 1982 and may be followed by a dry spell running from 1983 to 1992. Policy and management practices should be geared to prevent further desertification during this period. 相似文献
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The Sahel is prone to climate stressors such as droughts, winds and floods. This study employs a systematic review approach to track the frequency with which these stressors are reported in the scientific peer reviewed literature, examining publishing trends to identify which stressors are most reported, documenting the spatial distribution of these stressors from a country and regional perspective, and assessing the role played by climatic and non-climatic drivers in causing the stressors. A total of (n = 388) reports of stressors were documented in (n = 164) peer reviewed articles. From a country perspective, Southern Niger records the highest number of reports on all three stressors (15.97%), followed by Ethiopia (11.85%) and Senegal (10.56%). Regionally, West African Sahel recorded the highest number of reports on all stressors (49.97%) followed by East African Sahel (29.89%) and Central African Sahel (12.11%) respectively. Droughts are observed to be the most frequently reported stressor (n = 219), followed by floods (n = 123) and winds (n = 46). The decade 1975–1985 recorded the highest reports of stressors (n = 207), while the decade 1997–2007 recorded (n = 80) and the decade 1986–1996 recorded (n = 52). While climatic drivers are dominant (52%), there is however an increasing attribution of the drivers of the stressors to non-climatic drivers (47%). The main weakness of this study is that it uses peer reviewed papers dwelling on climate stressors as a proxy for climate stressors in the Sahel and a lot more studies could be hiding in non-peer reviewed studies, underscoring that this work provides a general and baseline overview of the climate stressors in the region. 相似文献
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Patrick J. Michaels 《Geoforum》1983,14(4):441-446
Objective statistical methods were used to determine the overall climatic sensitivity of wheat yields in Sonora, Mexico and the Southern United States Great Plains. The major differences between the two cultures can ultimately be ascribed to ‘genetic’ factors. The research was conducted to determine if the high-yielding variety (HYV) package is more sensitive to climatic fluctuation than the more traditional U.S. regime. Improved design Thompson-type models were developed for both areas, and were accepted as valid after tests on independent data. Both models had an rms error of 7% of the mid-1970s yields, when run on data withheld from the original specification. After validification, a series of sub-models were constructed that use successively less of the 1970s and 1960s data. Doing this corresponds to a removal of more and more HYV years from the Sonora model, while a similar period of increase (though non-HYV) is modeled in the U.S.A. The magnitudes of the regression coefficients of the most important climatic determinants of yield were then examined for significant changes. Yield sensitivities were found to increase approximately 300% in the Sonora model, while the results for the U. S. A. are more equivocal. The nature of the two agricultural packages suggest that the differences are ultimately ‘genetically’ related, and stem from changes in cultural practice related to the dwarfing gene. Because of physical limitations on the Sonora irrigation system, it is unlikely there will be an environmental remedy for this problem in the near future. The results suggest that it would be judicious to promote an increased wheat reserve policy, particularly as population climbs in countries adopting the HYV package. However, no formula for doing this while maintaining an adequate price structure is supplied here. 相似文献
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现代数值模拟技术是一种把数值模型与观测资料结合起来对地球系统状态进行理想化评估的方法。除了在数值天气预报和气候分析中发挥重要作用外，数据同化技术也被应用于气候研究的许多方面，如模式初始化、确认及最优化。主要通过几个与中国西部区域气候研究紧密相关的议题，讨论了数据同化在气候模拟中的应用。并且阐述了其将面对的挑战、潜在方法学、最新研究成果和未来发展。 相似文献
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1960-2005年南四湖流域气候变化趋势及其突变分析 总被引：2，自引：1，他引：1
利用1960-2005年南四湖流域22个气象台站逐月气温、降水量、 20 cm蒸发皿蒸发量资料, 分析了该流域近46 a来的气候变化趋势及其突变情况. 结果表明: 南四湖流域春季、冬季及年平均气温呈显著的上升趋势;四季及年降水量变化趋势不显著;四季及年蒸发皿蒸发量均呈显著的下降趋势, 且夏、春两季降幅大于秋、冬两季. 年平均气温在1985年发生了增温突变, 年降水量没有发生突变;年蒸发皿蒸发量在1969年和1985年发生年际突变. 利用单个环境因子的变化来解释蒸发皿蒸发量变化会产生偏颇. 相似文献
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There is much talk about current global warming, but that is not the main subject under discussion here. There is fairly general agreement on climate changes through geological time, and the cause or causes are becoming clearer. In this Feature, a simple backward look is given to climate events, particularly climatic cycles, in geological time, to help get in perspective some of the predictions for our near future. 相似文献