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1.
1928～1929年夏季,中国北方(34°～45°N,106°～122°E)和华南(20°～30°N,106°～122°E)地区遭受了严重的干旱,此次旱灾是中国近代十大灾荒之一。由于早期观测资料缺乏,数值模拟成为研究此次旱灾形成机制的重要手段。本研究诊断分析了挪威地球系统模式(NorESM1-F)过去千年试验中1928年和1929年的模拟。结果表明：模拟的1928年与1929年夏季中国东部季风区旱涝空间分布与历史记录重建非常相似;即1928年夏季,降雨集中在长江与黄河之间,而1929年夏季,降雨集中在长江中下游;其他地区降雨偏少。重建和观测资料证实NorESM1-F能够较好地模拟中高纬海表面温度异常;同时,模拟结果显示,这两年夏季北大西洋高纬地区以及北美西海岸的海表面温度偏高是造成这两年干旱的控制因素之一。它激发出影响东亚夏季降水的遥相关波列。1928年夏季,明显的正位相欧亚遥相关,导致东亚大槽加深、西太平洋副热带高压南撤、东亚夏季风减弱,并最终导致1928年夏季降水异常减少;而1929年夏季,中纬度的丝绸之路遥相关波列(SRP)使200 hPa南亚高压加强东伸、中国东部沿海地区出现正... 相似文献
2.
北京斋堂黄土中主要温室气体组分特征 总被引：4，自引：3，他引：1
根据极地冰芯等资料已经重建了过去大气温室气体（主要是CO2,CH4）浓度的变化。由于人类活动的影响,温室气体的含量自工业革命以来有了明显的上升,其影响表现为全球变暖。如果维持现在的CO2产放水平,根据气候模式预测到下个世纪末全球温度将增加l-3.5℃,可能极大地改变人类生存的环境。但是预测结果还存在着很大的不确定性,其中一个重要因素是对温室气体的源和汇的理解还不完善,有相当数量的CO2声向不明（即未知汇）.目前倾向认为,在北半球的中纬度地带可能存在着一个巨大的陆地生态系统汇（植被和土壤）.中国黄土分布在北半球中纬度,实际上是在干旱一半干旱气候条件下形成的一套巨厚的成土作用较弱的黄土一古土壤序列。 相似文献
3.
华北晚侏罗世—早白垩世风成砂主要分布于鲁西蒙阴盆地上侏罗统三台组、辽西金—羊盆地上侏罗统—下白垩统土城子组、冀西北尚义盆地上侏罗统—下白垩统土城子组/后城组（原阎家窑组）、鄂尔多斯盆地下白垩统志丹群和甘肃下白垩统河口群。各地风成砂岩均具高角度大型—巨型板状、楔状交错层理及平行层理,分选较好—好,磨圆次棱角状—次圆状等沉积特征。对华北晚侏罗世—早白垩世风成砂赋存层位以及风成砂岩形成时代进行了对比,将风成砂主要划分为3个时期,即基末利期—贝利阿斯期、凡兰吟期—欧特里夫期和欧特里夫期—阿普特期,且从鲁西到甘肃风成砂岩形成时代逐渐变新。通过上述5个地区风成砂的古风向研究发现,当时西北风盛行,古地磁研究显示风成砂岩发育于N25°—N45°之间区域。根据当前全球风带分布特征,认为华北晚侏罗世—早白垩世处于西风带上,为行星风系所控制。通过对比南半球同期风成砂岩古风向研究,提出全球南北半球中纬度地区均处于西风带上。结合风成砂及相应层位沉积特征、沉积环境的研究,初步推测晚侏罗世—早白垩世,华北N30°以北地区为干旱寒冷气候,而N30°以南地区则干旱炎热,华北北部整体处于海拔较高的山地环境,山间盆地发育,火山活动频发。燕辽生物群与热河生物群的演替过程与风成砂沉积相耦合,体现了古地理、古环境对生物群发展的制约作用。 相似文献
4.
气候增暖背景下,东亚干旱半干旱区降水发生了显著变化,水汽输送变化对该区域降水异常具有重要作用。回顾和梳理了近年来关于东亚干旱半干旱区的水汽来源的研究,重点关注外部水汽输送来源、季节差异以及局地蒸散发变化,讨论并展望了未来研究方向。现有研究表明,来自孟加拉湾—印度洋、南海、西太平洋和欧亚大陆陆地蒸散发的水汽分别通过南亚季风、南海季风、副热带季风和中纬度西风带传输至东亚干旱半干旱区,夏季以来自南海和西太平洋的水汽占主导,冬季基本取决于西风所携带的水汽含量。1979年以来,东亚干旱半干旱区年降水再循环率均呈现增加趋势,季节尺度夏季的再循环率高于冬季。未来主导东亚干旱半干旱区水汽输送特别是夏季水汽输送进而影响降水的源地以及路径需要进一步验证,量化外部输入水汽和内部蒸散发水汽相对贡献的研究或将成为未来研究热点,全球变暖背景下降水水汽来源变化仍需进行更为深入的研究探讨。 相似文献
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6.
在总结下黄岩区块各项开发地质条件的基础上,通过合理储量法、经济极限井距法、模拟法等对研究区的井网井距进行优化,最终认为开发井网方向沿N60°E和N30°W,按300m×250m进行布置最优,有利于取得较好的经济效益,提高资源的利用率。 相似文献
7.
鄂尔多斯地区倒数第二次冰期冰楔假型的发现以及中国倒数第二次冰期多年冻土边界重建 总被引：3，自引：2，他引：1
首次发现鄂尔多斯地区发育有倒数第二次冰期冰楔假型,并根据此发现结合以往资料恢复了中国倒数第二次冰期多年冻土的边界,即105° E以东,118° E太行山一线以西地区的冻土南界在36°33' N附近,太行山以东地区位于40°20' N附近;而105° E以西的青藏高原地区多年冻土则分布在36°～29° N,现代海拔为2 000～3 100 m的地区.边界附近倒数第二次冰期时的年均气温比现今要低10～15 ℃. 相似文献
8.
水资源约束下的阿克苏河流域适宜绿洲规模分析 总被引：2，自引：0，他引：2
阿克苏绿洲是中纬度干旱区典型的绿洲灌溉系统,制定绿洲适宜发展规模、明确适宜耕地面积,可为实现绿洲的生态稳定与可持续管理提供科学依据。以中国西北干旱区的阿克苏河流域为研究对象,基于作物需水量和绿洲适宜面积模型的水热平衡法,借助典型绿洲结构模型,计算了阿克苏绿洲的适宜耕地面积。结果表明：2010-2015年阿克苏灌区的作物需水量高达740.3 mm,较20世纪60年代的539.6 mm增加了37.2%;考虑到山区来水和下泄塔里木河干流的水量要求,阿克苏绿洲的可用水量为42.6×108 m3;阿克苏河流域绿洲已处于不稳定状态,耕地面积超过了水资源承载能力。计算得出绿洲适宜规模为12 430 km2,与现有水平相当。基于作物需水量和绿洲适宜面积模型的水热平衡算法计算的阿克苏绿洲的适宜耕地面积分别为4 674 km2和4 211 km2,需要在当前耕地水平上退耕18%至26%。 相似文献
9.
全球气候变化影响了气象水文要素的时空分布特性,气象水文干旱事件的转化关系及风险传播特征亟待研究。基于站点、栅格观测资料和CMIP5（Coupled Model Inter-comparison Project Phase5）的19个气候模式输出数据,采用新安江等4个水文模型模拟了中国135个流域历史（1961—2005年）和未来时期（2011—2055年,2056—2100年）的水文过程,计算了SPI（Standard Precipitation Index）和SRI（Standard Runoff Index）干旱指标,通过游程理论识别了气象干旱与水文干旱事件,利用Copula函数与最大可能权函数度量二维干旱风险特征,定量评估了气象干旱至水文干旱的潜在风险传播特性。结果表明:①气象-水文干旱对气候变化响应强烈,华北和东北地区的干旱联合重现期增大,干旱潜在风险减小,华中和华南地区的干旱联合重现期减少60%~80%,干旱潜在风险增加;②气象干旱与水文干旱风险在历史和未来时段均存在显著的正相关关系,相关系数超过0.99;③各流域水文干旱风险变化对气象干旱风险变化的敏感程度不会随气候变暖发生较大变化,但未来北方地区水文干旱同气象干旱同时发生的概率将会小幅度增加。 相似文献
10.
中国钾盐资源匮乏,目前陆相钾盐资源已基本探明,但海相找钾还没有取得重大进展,然而,要想建立适合中国小陆块海相成钾理论框架,实现海相找钾突破,一个重要基础性工作是确定特定时段中国小陆块典型海相盆地的古地理纬度。而古地磁学是确定陆块的纬向运动,开展古地理重建的最有效手段。文章针对中国4类成钾潜力较高的典型海相盆地所属陆块——华北、华南、羌塘、兰坪-思茅陆块,通过收集、评价和筛选以往古地磁研究成果,总结了这些陆块在主要成盐成钾阶段的古纬度变迁历史,确定华北陆块(绥德)在中、晚奥陶世的古纬度为9.2°S~14.2°S,华南陆块(成都)在三叠纪的古纬度为10.6°N~23.1°N,羌塘陆块(雁石坪)在中、晚侏罗世的古纬度为14.6°N~27.5°N,兰坪-思茅盆地(江城)在白垩纪至古新世的古纬度为20.9°N~27.6°N。同时,为了更好地探讨兰坪-思茅盆地的成钾潜力,对与其相邻的已发现巨型钾盐矿床的印度支那块体开展了相应时段的古纬度研究,确定该陆块(万象)在白垩纪的古纬度约为21.1°N~21.3°N。最后,综合古纬度和其他地质证据,从大地构造背景上探讨了4个陆块的成盐、成钾条件。 相似文献
11.
Surface air temperature is one of the main factors that can be used to denote climate change. Its variation in the westerly
and monsoon-influenced part of China (i.e., North-West and East China) were analyzed by using monthly data during 1961–2006
from 139 and 375 meteorological stations over these two regions, respectively. The method of trend coefficient and variability
was utilized to study the consistency and discrepancy of temperature change over North-West and East China. The results suggest
that whether for the annual or the seasonal mean variations of temperature, there were consistent striking warming trends
based on the background of global warming over North-West and East China. The most obvious warming trends all appeared in
winter over the two regions. Except for the period in spring, the annual and seasonal mean warming trends in North-West China
are more obvious than those in East China. The annual mean temperature warming rates are 0.34°C per decade and 0.22°C per
decade over North-West and East China, respectively. The average seasonal increasing rates in spring, summer, autumn, and
winter are 0.22°C per decade, 0.24°C per decade, 0.35°C per decade, and 0.55°C per decade in North-West China, respectively.
At the same time, they are 0.25°C per decade, 0.11°C per decade, 0.22°C per decade, and 0.39°C per decade in East China, respectively.
The temperature discrepancies of two adjacent decades are positive over the westerlies and monsoonal region, and they are
bigger in the westerlies region than those in the monsoonal region. The most significant warming rate is from the North-East
Xinjiang Uygur Autonomous Region of China to West Qinghai Province of China in all seasons and annually over the westerlies
region. The North and North-East China are the main prominent warming areas over the monsoonal region. The warming rate increases
with latitude in the monsoonal region, but this is not the case in the westerlies region. 相似文献
12.
三大自然区过渡地带近50年来气候类型变化及其对气候变化的响应 总被引：2，自引：0，他引：2
The transition area of three natural zones (Eastern Monsoon Region, Arid Region of Northwest China, Qinghai Tibet Plateau Region) is influenced by the Asian monsoon and middle latitude westerly circulation because of its special geographical position. And it is more sensitive to global climate change. The Koppen climate classification, which is widely used in the world, and the accumulated temperature-dryness classification, which is usually used in China, were used to study the climate zones and changes in the region of longitude 97.5°~108°E, latitude 33°~41.5°N, from 1961 to 2010. The changing areas of each climate zone were compared to the East Asian Summer Monsoon index, the South Asian Summer Monsoon index, the Summer Westerly index, the East Asian Winter Monsoon index, the Plateau Summer Monsoon index, the North Atlantic Oscillation index, the Southern Oscillation index, NINO3.4 index, to explore the response of the transition area of three natural zones to each climate system. According to the results, this region will become wetter when the Summer Westerly or the East Asian Winter Monsoon is relatively strong. When the East Asian Summer Monsoon or the South Asian Summer Monsoon becomes strong, the climate in low altitude region of the study area will easily become drier, and the climate in high altitude region of the study area is easily to become wetter. When the Plateau Summer Monsoon is relatively strong, the climate in the study area will easily become drier. When the North Atlantic Oscillation is relatively strong, the study area will easily become wetter. And when the El Niño is relatively strong, or the Southern Oscillation is relatively weak, the study area will easily become drier. In general, the moisture status of this region is mainly controlled by the middle latitude westerly circulation. The enhancement of the Asian summer monsoon could increase the precipitation in the southeast part of this regional, but, according to the degrees of dryness and the types of climate change in this paper, warming effects could offset precipitation increasing and make the area drier. The transition area of three natural zones is influenced by multiple interactions of climate systems from East Asia. A single climatic index, such as air temperature or precipitation, can not completely represent the regional features of climate change. As a result, areas of climate zones can be used as an important index in the regional climate change assessment. 相似文献
13.
河西内陆河流域出山径流对气候转型的响应 总被引：39，自引：14，他引：25
对甘肃河西内陆河流域出山径流变化过程与趋势的研究表明,从20世纪80年代中后期开始,受西风环流降水的影响,祁连山区中、西部的黑河、疏勒河流域的气候环境发出了由增温变干转为变湿的讯号,具体表现为随着山区气温升高,降水量增加,出山径流相应增大.采用区域气候模式预测和水文统计模式的计算,亦同样证实出山径流有显著的增加趋势.但受季风影响的祁连山东部的石羊河流域则尚未出现这种转变,从20世纪50年代起,出山径流量持续下降,表明其气候环境仍向增温变干的方向发展. 相似文献
14.
ANDREI A. VELICHKO OLGA K. BORISOVA ELLA M. ZELIKSON 《Boreas: An International Journal of Quaternary Research》2008,37(1):1-19
Main climatic indexes (mean January, July and annual temperatures; duration of the frost‐free period; seasonal and annual precipitation; and annual potential evaporation) are estimated for the Last Interglacial Eemian–Mikulino–Kazantsevo–Oxygen Isotopic Substage 5e) climatic optimum in northern Eurasia. Reconstructions are based on the palaeofloristic data from 29 sites. The distribution of temperature deviations from present‐day values in northern Eurasia, as well as in the northern hemisphere as a whole, indicates certain areas where temperatures during the Last Interglacial climatic optimum were lower than at present. The greatest positive deviations occurred in the high latitudes and gradually decreased towards mid‐latitudes. At about 45°N the mean January temperature was close to that of the present day. For the mean July temperature, the zone with minor deviations is situated further to the north, at 55°N. South of 50°N, an area with small negative temperature deviations from the present‐day values is reconstructed. A similar decrease in temperature deviations from high to low latitudes was the general tendency in various warm epochs, including the Holocene and the Eocene optima. In the arid and semi‐arid regions of northern Eurasia, a considerable increase in precipitation took place, while air temperatures were close to those of the present or even slightly lower. Another peculiarity of the climate in the Last Interglacial climatic optimum relates to the meridional temperature gradient, one of the factors strongly influencing the intensity of the Westerlies in the mid‐latitudes of the northern hemisphere. Our reconstructions for northern Eurasia tend to contradict this rule. The paradox can be explained by a compensation mechanism: a substantial increase in winter temperature in Siberia indicates that the Siberian atmospheric High was weaker and smaller at the Last Interglacial climatic optimum than at present. The reduced role of the Siberian High was compensated by more frequent invasions of the Atlantic air masses from the west, even though the meridional temperature gradient was smaller than at present. 相似文献
15.
Jan Ho&#x;ek Jind&#x;ich Prach Marek K&#x;íek Petr &#x;ída Piotr Moska Petr Pokorný 《Boreas: An International Journal of Quaternary Research》2019,48(4):988-1005
Pronounced climatic warming associated with the Late Weichselian Pleniglacial‐to‐Lateglacial transition caused considerable environmental changes throughout the former periglacial zones (in Europe ~53°–46°N). During permafrost degradation and subsequent ground subsidence (i.e. thermokarst processes), the landscape changed rapidly. In this study we investigated a flat mid‐altitude area in south Bohemia, Czech Republic, lying close to the southern limit of the Weichselian permafrost. We discovered palaeo‐lake basins with sedimentary infillings up to 11 m in depth. According to radiocarbon and palynostratigraphical dating, these basins were formed at the onset of the Late Pleniglacial‐to‐Lateglacial transition, whereas the smaller depressions were formed later. We suggest that the basins resulted from thermal and fluvio‐thermal erosion of the former permafrost and represent remnants of discontinuous gullies and possibly collapsed frost mounds (pingo/lithalsa scars). The formation of this a fossil thermokarst landscape was climatically driven and multiple phased, with the major phase during the climatic warming and wetting at the onset of GI‐1e (Bølling) and the minor phase during GI‐1c (Allerød). This study enhances knowledge of the palaeogeography of the former European periglacial zone by showing that Late Pleistocene thermokarst activity could have had a significant impact on the evolution of the landscape of at least some regions of central Europe along the southern limit of the continuous permafrost zone. The research also points to a similar history for the physical transformation of the landscape of the former European periglacial zone and current thermokarst landscapes and could be a valuable source of information with respect to the future transformation of the Arctic under conditions of ongoing global warming. 相似文献
16.
中国北方有大面积的土地被沙漠和黄土覆盖,是现代沉积和侵蚀比较活跃的地区。强烈的地表过程不仅影响着区域的生产生活活动,还通过粉尘传输影响北半球甚至于更大范围的气候和环境。长期以来,由于综合研究不够,对沙漠-黄土体系的沉积和侵蚀规律以及未来趋向的认识有限。结合对沙漠沙地-黄土沉积的高密度光释光年代测试结果,基于地统计法和遥感分析的黄土堆积量估算以及现代降尘、地表侵蚀的观察研究,认为沙漠沙地-黄土堆积区的沉积和侵蚀过程受气候变化控制,这里既是堆积区,又是侵蚀区,处于动态变化过程中;黄土比沙地沉积保存着更完整的过去气候变化信息。黄土高原水蚀和风蚀在地质历史时期就存在,人类活动加强了侵蚀过程,但可能还没有实质性地改变这一趋向。通过对地质记录和古气候模拟结果的分析,在未来全球变暖的背景下,沙地地区可能由于有效湿度减少变干而使风尘活动加强,黄土高原地区的粉尘沉积速率也将随之加快。 相似文献
17.
台湾-吕宋岛双火山弧的构造意义 总被引：3，自引：0，他引：3
扼要评介了国内外关于台湾-吕宋岛双火山弧在南海沿马尼拉海沟俯冲的动力学过程和俯冲板块深部形态等方面研究的成果;认为目前的动力学模式还不够完善,没有能够对台湾-吕宋岛双火山弧中存在的第四纪火山间断做出合理的解释,为此引入“板片窗”概念,对已经提出的动力学模式进行了修改;并统计1964~2006年发生于菲律宾地区的地震震中位置,认为存在于菲律宾群岛17°~19°N之间的深源地震稀疏带和存在于14°~15°N之间的喇叭状地震稀疏带是地震作用对于南海板片窗构造存在的反映;结合研究区域已有应力场研究资料,认为俯冲的南海亚板块中板片窗两侧俯冲倾角的差异,应该是造成俯冲带内应力分布出现分带现象的原因之一。 相似文献
18.
Analysis of extreme low-temperature events during the warm season in Northeast China 总被引：2，自引：0，他引：2
The trends of global warming are increasingly significant, especially in the middle and high latitude regions of the northern
hemisphere, where the impact of climate change on extreme events is becoming more noticeable. Northeast China is located in
a high latitude region and is sensitive to climate change. Extreme minimum temperatures causing cold damage during the warm
season is a major type of agro-meteorological disaster in Northeast China, which causes serious reductions in crop yield.
In this paper, we analyzed the temporal and spatial trends in the frequency of extreme minimum temperatures during the warm
season (from May to September) during 1956–2005 in Northeast China. Abrupt climatic changes were identified using the Mann–Kendall
test. The results show that the frequency of extreme minimum temperature days during the warm season in Northeast China decreases
significantly from 1956 to 2005 with a background of climate warming. The highest number of extreme minimum temperature days
occurred in the 1970s and 1980s, and there was an abrupt climatic change in 1993. The spatial analysis identified that the
north and southeast of the region experienced a larger decrease in the number of extreme low temperature days than the west
and south of the region. Rice, sorghum, corn, and soybeans are most vulnerable to cold damage. In severe low temperature years,
the average crop yield was reduced by 15.2% in Northeast China. 相似文献
19.
Zhu Hong Yang Guanxiu Sheng AxingChina University of Geosciences Beijing 《《地质学报》英文版》1996,70(4):356-365
In western Henan, Late Palaeozoic coal measures are completely developed and well exposed. A great deal of research work on biostratigraphy was done by predecessors. After systematic palaeomagnetic studies, we have confirmed the existence of the Permian Kiaman reversed polarity epoch in the study region. Its palaeolatitude varied from 11.2° N(P,) to 15.6°N(P2). This provides important evidence for the view that this region was situated in a low latitude climatic zone in this period and gradually moved northwards from the tropic rain forest climate area to the tropic arid-humid seasonal climate area during this stage. 相似文献
20.
Bjrn E. Berglund Svante Bjrck Geoffrey Lemdahl Helene Bergsten Kjell Nordberg Else Kolstrup 《第四纪科学杂志》1994,9(2):127-132
A synthesis is presented of the envronmental and climatic variations that are inferred to have occurred in southern Sweden (up to latitude 59°N) and Denmark during the Weichselian Late-glacial (14-9 ka BP). The chronology and characteristics of the main phases of deglaciation, sea-level change, periglacial activity, soil development, vegetation cover and climate change are summarised. A curve representing the main changes in temperature, including quantitative estimates based upon beetle data and using the ‘mutual climatic range’ method, is presented. 相似文献