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1.
Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance 
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下载免费PDF全文 Plagioclases occur mainly as phenocrysts in volcanic rocks of King George Island, South Shetland Islands, West Antarctica. In basaltic andesites and andesites of Keller Peninsula and Ullman Spur (Admiralty Bay), they are high structure state labradorite andesines; and in high Al basalts and basaltic andesites of Barton and Weaver peninsulas (Maxwell Bay), they are high structure state bytownite anorthites.∑[WT9.BZ]REE, La/Yb ratios and δEu values of plagioclases from Admiralty Bay are higher than those from Maxwell Bay. All plagioclases have rather identical chondrite normalized transitional element distribution patterns, probably reflecting that crystal structure rather than composition of plagioclase controls their diversity. Compositions of plagioclases depend chiefly on those of their host rocks, compositional differences of plagioclases reveal that basaltic magmas in the Admiralty Bay area are more evolved than in the Maxwell Bay area. 相似文献
2.
黄河源区径流对气候变化的响应及未来趋势(英文) 总被引：4，自引：1，他引：3
This study examines the hydrological and meteorological data of the source region of the Yellow River from 1956 to 2010 and future climate scenarios from regional climate model (PRECIS) during 2010-2020. Through analyzing the flow variations and revealing the climate causes, it predicts the variation trend for future flows. It is found that the annual mean flow showed a decreasing trend in recent 50 years in the source region of the Yellow River with quasi-periods of 5a, 8a, 15a, 22a and 42a; the weakened South China Sea summer monsoon induced precipitation decrease, as well as evaporation increase and frozen soil degeneration in the scenario of global warming are the climate factors, which have caused flow decrease. Based on the regional climate model PRECIS prediction, the flows in the source region of the Yellow River are likely to decrease generally in the next 20 years. 相似文献
3.
CHIN-KWEI LEE 《地理学报(英文版)》1934,(2)
The classification of soils in China is essentially following Marbut's system~2.It is first grouped into Pedocals and Pedalfers depending upon their lime content in the soil profiles. Pedocals are predominant in North China where precipitation is not enough to leach out the lime in the soils. While Pedalfers arepredominant in South China where the rainfall is higher. Each of the mainsoil types is briefly described as follows: 相似文献
4.
CHIN-KWEI LEE 《地理学报》1934,(2)
The classification of soils in China is essentially following Marbut's system~2.It is first grouped into Pedocals and Pedalfers depending upon their lime content in the soil profiles. Pedocals are predominant in North China where precipitation is not enough to leach out the lime in the soils. While Pedalfers arepredominant in South China where the rainfall is higher. Each of the mainsoil types is briefly described as follows: 相似文献
5.
Forty-eight samples are chosen to discuss the distribution in space and time of the cooling fluctuation events during HoloCene in the tropical zone of China in this paper. The authors consider that the Neoglaciations II and III (or Cooling Event ①) have a widespread impact on the drop in temperature of 1-2 oC or less than 2 oC. The YD Event was dated at 11,300-10,200 a BP in the tropical mainland and its dating is 11,400-10,500 a BP in the sea area with a drop in temperature of 4-6 oC. The distribution of Event B and Neoglaciation I is taking a position of north, with a drop in temperature of 2.5-3.0 oC. The Cooling Event ② shows the temporality in time. The Cooling Event ③ shows the limitation of regional distribution with a drop in temperature of less than 1.5oC. The more recent the cooling event is, the smaller the drop amplitude in temperature will be. In the eastern part of tropical zone seven events are complete in all varieties but the cooling fluctuation is weaker in the western part. In Hainan Island and South China Sea the appearance of cooling fluctuations is synchronous with each other. 相似文献
6.
中国南部夏季季风降水水汽来源的稳定同位素证据 总被引：2，自引：0，他引：2
Summer monsoons （South Asian monsoon, South China Sea monsoon and Subtropical monsoon） are prominent features of summertime climate over southern China. Dif- ferent monsoons carry different inflow moisture into China and control the temporal and spatial distributions of precipitation. Analyses of meteorological data, particularly wind, tempera- ture and pressure anomalies are traditional methods of characterizing moisture sources and transport patterns. Here, we try to utilize the evidence from stable isotopes signatures to trace summer monsoons over southern China. Based on seven CHNIP （Chinese Network of Iso- topes in Precipitation） observatory stations located in southern China, monthly composite precipitation samples have been collected and analyzed for the composition of δ^18O during July, 2005. The results indicated that the spatial distributions of δ^18O in precipitation could properly portray the moisture sources together with their transport pathways. Moreover, the amount effect, altitude effect, temperature effect and the correlation between δ^18O vs. relative humidity were discussed. 相似文献
7.
Coastline configuration indexes of 34 typical arc-shaped coasts in South China are investigated by the method of principal component analysis, and meanwhile deposition and geomorphologic features of arc-shaped coast are also analyzed. The results show: (1) The configuration of arc-shaped coast in South China is of the characteristic of variability and complexity. (2) The wave power and the openings of the bay are the decisive factors to result in the changes of the configuration of the arc-shaped coast in South China, however, incidence direction of the wave has no effect on configuration development of the coast. (3) Commonly, geomorphologic modes of the arc-shaped coast system in South China consist of barriers, lagoons and tidal-inlets, and can be divided into four types:the openings of the bay leaning to the east, the openings of the bay leaning to the south, the openings of the bay leaning to the west and the openings of the bay leaning to the north. 相似文献
8.
Based on 22 sparse-distributed tide gauge records in the Northwest Pacific Ocean marginal sea, the process, characteristic and prediction of regional sea level change are discussed by the integration of the following methods. Firstly, the regularized EM algorithm (RegEM) and the Multi-taper Spectral Method (MTM) are adopted to interpret their multiscale fluctuation processes and their spatial-temporal variations. Secondly, the orderly cluster method is introduced to classify these tidal stations, and with the consideration of the space adjacent relation, we obtain five sub-regions (the coasts of Bohai Sea-northern Yellow Sea, Yellow Sea-East China Sea along Chinese coast, the East China Sea along Japanese coast, the southern East China Sea and the northwestern South China Sea). Furthermore, the Mean Generation Function (MGF) is explored to predict the medium- and long-term trends of each tide station. Finally, the Principal Component Analysis (PCA) is employed to obtain re-gional-scale sea level change trends, sea level rise rates of the above five sub-regions from 2001 to 2030 are 1.23-1.27 mm/a, 3.30-3.34 mm/a, 2.72-2.76 mm/a, 1.43-1.47 mm/a and 1.13-1.15 mm/a respectively, and the whole region sea level rise rate is between 2.01 mm/a and 2.11 mm/a. The aim of our work is to conduct an integrated research on regional sea level change. 相似文献
9.
中国南方冬季异常低温和降水事件 总被引：6，自引：1，他引：5
This paper analyzed the anomalous low-temperature events and the anomalous rain-abundant events in January since 1951 and winter since 1880 for southern China.The anomalous events are defined using ±1σ thresholds.Twelve cold Januaries are identified where temperature anomaly below-1σ,and ten wet Januaries are identified where precipitation anomaly above +1σ.Among these events there are three patterns of cold-wet Januaries,namely 1969,1993 and 2008.The NCEP/NCAR reanalysis data are used to check the atmospheric circulation changes in association with the anomalous temperature and precipitation events.The results show that the strong Siberian High(SBH),East Asian trough(EAT) and East Asian jet stream(EAJS) are favorable conditions for low-temperature in southern China.While the anomalous southerly flow at 850 hPa,the weak EAT at 500 hPa,the strong Middle East jet stream(MEJS) and the weaker EAJS are found to accompany a wetter southern China.The cold-wet winters in southern China,such as...更多 January of 2008,are mainly related to a stronger SBH,and the circulation in the middle to upper troposphere is precipitation-favorable.In wet winters,the water vapor below 500 hPa is mainly transported by the anomalous southwesterly flow and the anomalous southern flow over the Indo-China Peninsula and the South China Sea area.The correlation coefficients of MEJS,EAMW(East Asian meridional wind) and EU(Eurasian pattern) to southern China precipitation in January are +0.65,-0.59 and-0.48 respectively,and the correlations for high-pass filtered data are +0.63,-0.55 and-0.44 respectively,the significant level is all at 99%.MEJS,EAMW and EU together can explain 49.4% variance in January precipitation.Explained variance for January and winter temperature by SBH,EU,WP(west Pacific pattern) and AO(Arctic Oscillation) are 47.2% and 51.5%,respectively.There is more precipitation in southern China during El Nio winters,and less precipitation during La Nia winters.And there is no clear evidence that the occurrence of anomalous temperature events in winter over southern China is closely linked to ENSO events. 相似文献
10.
《地理学报》2009,30(4):471-488
This paper analyzed the anomalous low-temperature events and the anomalous rain-abundant events in January since 1951 and winter since 1880 for southern China.The anomalous events are defined using ±1σ thresholds.Twelve cold Januaries are identified where temperature anomaly below-1σ,and ten wet Januaries are identified where precipitation anomaly above +1σ.Among these events there are three patterns of cold-wet Januaries,namely 1969,1993 and 2008.The NCEP/NCAR reanalysis data are used to check the atmospheric circulation changes in association with the anomalous temperature and precipitation events.The results show that the strong Siberian High(SBH),East Asian trough(EAT) and East Asian jet stream(EAJS) are favorable conditions for low-temperature in southern China.While the anomalous southerly flow at 850 hPa,the weak EAT at 500 hPa,the strong Middle East jet stream(MEJS) and the weaker EAJS are found to accompany a wetter southern China.The cold-wet winters in southern China,such as...更多 January of 2008,are mainly related to a stronger SBH,and the circulation in the middle to upper troposphere is precipitation-favorable.In wet winters,the water vapor below 500 hPa is mainly transported by the anomalous southwesterly flow and the anomalous southern flow over the Indo-China Peninsula and the South China Sea area.The correlation coefficients of MEJS,EAMW(East Asian meridional wind) and EU(Eurasian pattern) to southern China precipitation in January are +0.65,-0.59 and-0.48 respectively,and the correlations for high-pass filtered data are +0.63,-0.55 and-0.44 respectively,the significant level is all at 99%.MEJS,EAMW and EU together can explain 49.4% variance in January precipitation.Explained variance for January and winter temperature by SBH,EU,WP(west Pacific pattern) and AO(Arctic Oscillation) are 47.2% and 51.5%,respectively.There is more precipitation in southern China during El Nio winters,and less precipitation during La Nia winters.And there is no clear evidence that the occurrence of anomalous temperature events in winter over southern China is closely linked to ENSO events. 相似文献
11.
The analysis results of oxygen isotopes, carbon isotopes, geochemistry and the growth belt of reef coral etc. for some profiles of coral reef show that the basic pattern of climatic fluctuation during the Quaternary period can be reflected by coral reef. The trend of climate change was from cooling to warming during the Early Pleistocene with at least four cycles, and from warming to cooling with at least seven cycles during the Middle Pleistocene. The late Pleistocene is a period of the Quaternary which shows the most frequent variation of climate but generally two main cycles of warming–cooling can be seen. During the Holocene the climate went through a process of warming-rise in temperature-drop in temperature. During the historical period there were four cycles of cooling-warming at 1700 a BP. During the last 200 years climate change is characterized by two stages; a positive deviation in the former 100 years, and a negative deviation in the latter 100 years with general warming trend. 相似文献
12.
中国热带珊瑚礁的第四纪气候记录 总被引：1，自引：0，他引：1
珊瑚礁剖面的氧碳同位素、地球化学、造礁珊瑚生长带等分析结果表明,珊瑚礁记录了第四纪气候波动的基本轮廓.早更新世总体趋暖,但至少有4个旋回.中更新世总体趋冷,但至少有7个旋回.晚更新世气候剧烈波动,但总体变化为两个前暖后冷的旋回.全新世为回暖-升温-降温的波动.历史时期约1 700 a来有4个前冷后暖的旋回.近200 a的气候波动表现为前百年正距平,后百年以负距平为主,但总体趋暖. 相似文献
13.
About 70 examples of Quaternary fauna in China's tropics are enumerated in this paper. Of which about 40% of the examples can be found even in cooling stages, showing the smaller amplitude of climatic fluctuation during Quaternary. According to the temporal and spatial distribution of tropical faunas, the following characters of climate variation can be evidenced: two main cycles in Early Pleistocene, three main cycles in Middle Pleistocene, two main cycles in Late Pleistocene and Holocene Megathermal. The drop in temperature during the Latest Glacial Period and Neoglaciation has not endangered the existence of tropical faunas. With influence of cooling fluctuation during historical period, some faunas have removed southwards progressively, but disappearance of these animals in China's tropics was mainly the result of artificial factors. 相似文献
14.
中国热带第四纪动物群与气候波动 总被引：1，自引：0，他引：1
About 70 examples of Quaternary fauna in China‘s tropics are enumerated in this paper. Of which about 40% of the examples can be found even in cooling stages, showing the smaller amplitude of climatic fluctuation during Quaternary. According to the temporal and spatial distribution of tropical faunas, the following characters of climate variation can be evidenced: two main cycles in Early Pleistocene, three main cycles in Middle Pleistocene, two main cycles in Late Pleistocene and Holocene Megathermal. The drop in temperature during the Latest Glacial Period and Neoglaciation has not endangered the existence of tropical faunas. With influence of cooling fluctuation during historical period, some faunas have removed southwards progressively, but disappearance of these animals in China‘s tropics was mainly the result of artificial factors. 相似文献
15.
利用华北平原中部衡水水文地质科研深孔的岩芯,对平原区古土壤钙结核层碳氧同位素组分的古气候环境意义及相关气候指标的定量转换进行探讨,发现碳氧同位素对古气候变化具有较好的响应关系:3.5MaB.P.以来华北平原古气候逐渐由湿润转向干旱,早更新世由多个干湿冷暖旋回组成,晚期气候由暖迅速转凉;中更新世气候略温和,由3个冷干-暖湿旋回组成;晚更新世气候变化趋势为湿润-干燥-湿润,总体上呈现增温趋势。进入全新世后,δ13C平均值(-5)较低,属于相对湿润期;δ18 O平均值(-9.5)较低,属于相对寒冷期。应用相关公式可以定量恢复古温度变化,但平原区古土壤层受后期地下水作用的影响较大,如何消除这一影响还需更多数据支持。 相似文献
16.
I. MARIANNE LAGERKLINT GUNHILD ROSQVIST OTTO HERMELIN KIRK MAASCH 《Geografiska Annaler: Series A, Physical Geography》2005,87(1):111-124
ABSTRACT. A new high-resolution, alkenone-de-rived record of sea-surface temperature (SST) change covering the last 26000 years was obtained from the east-equatorial Atlantic off the Congo River. Temperature fluctuations correspond to climate change recorded in other marine and terrestrial archives of the region. The maximum temperature difference between 26000 years BP ago and the Holocene climate optimum around 6000 years BP was 4.3°C, corroborating other SST estimates from the same area. The coldest conditions were followed by a warming that began at 24000 calendar years BP, a time when Northern Hemisphere ice sheets were still at their maximal position. This comparatively early warming is in agreement with previous findings from the east-equatorial South Atlantic. After a relatively stable period between 21500 and 14500 calendar years BP, a second warming began at 14500 calendar years BP which coincides with the onset of the African Humid Period. A cool period at 11500 calendar years BP halted this warming but the trend of increasing temperatures began again at 10000 calendar years BP, this time through large-scale oscillations. The warmest time, around 6000 calendar years BP, was followed by a modest cooling that coincides with the end of the African Humid Period and the onset of Neoglaciation on the African continent. Following this the record shows two distinct warming-cooling cycles during the late Holocene. 相似文献
17.
联合国政府间气候变化专门委员会（IPCC）报告近百年升温约0.74℃,并将气候变化归因于人为排放的温室气体,然而该报告中的多处结论引起了国际社会对IPCC报告的广泛质疑.人为排放的温室气体对全球升温贡献有多大？人为过程与自然过程对全球变暖分别贡献多少？IPCC评估报告中过去百年0.74℃的变化是否为变冷总趋势中的次级波动？针对这些问题,本研究梳理了近年来全球气候变化的相关研究成果.结果显示,第四纪以来的地球气候波动主要受控于太阳辐射变化周期,各个时间尺度上的气候变化既表现出明显的周期性,也同时存在次一级的波动.在全新世晚期气候变冷的背景下,气候变化千年—百年尺度上同样存在一系列周期性和次级波动,且波动范围在0.5～6℃之间变化.IPCC报告中百年气候变暖的合理解释是全球变冷趋势下的次级波动. 相似文献
18.
全球气候变化下南海诸岛保护优先区识别分析 总被引：3，自引：1，他引：2
全球变化下,珊瑚礁保护区是保护生物多样性、增强珊瑚礁对气候变暖抵抗力的有效方式,而维持珊瑚礁弹性是其核心内容。针对珊瑚礁最具有威胁性的热压力因子,基于南海1982—2009年卫星观测海表面温度（SST）数据和CMIP5加拿大地球系统模式CanESM2模型预估的2006—2100年南海SST数据构建热压力强度模型,从维持珊瑚礁弹性的角度识别IPCC RCP 4.5和RCP 8.5情景下南海诸岛保护优先区。结果表明：RCP 4.5和RCP 8.5情景下13%左右的南海诸岛珊瑚礁识别为保护优先区。根据热压力强度与珊瑚抵抗力及避难所关系,西沙群岛七连屿和晋卿岛近年观测与未来预估的热压力强度均比较低,在保障其服务功能的基础上建议实施完全保护;东沙群岛东沙环礁和中沙环礁排洪滩近年观测急性热压力强度较高但未来预估热压力强度较低,建议实施50%禁止利用保护;中沙群岛黄岩岛近年观测和未来预估的急性热压力强度均比较低,建议实施50%多用途保护。南沙群岛有14%左右的珊瑚礁识别为保护优先区,根据其热压力强度可实施30%~100%禁止利用保护或30%~50%多用途保护。RCP 4.5和RCP 8.5情景下的南海诸岛保护优先区及保护对策,可为维持珊瑚礁生态弹性及应对全球气候变化提供重要的参考价值。 相似文献
19.
中国热带第四纪动物群与气候波动 总被引：2，自引：0，他引：2
中国热带第四纪动物群的70多个实例约有40%出现在冷期,反映气候波动幅度较小.动物群的时空分布可以佐证早更新世气候波动的2个主旋回、中更新世的3个主旋回、晚更新世的2个主旋回和全新世大暖期.末次冰期和新冰期未曾危及热带动物群的生存.历史时期的冷波动使动物逐步南迁,但其绝迹主要是受人为因素影响. 相似文献
20.
利用长城和中山站的多种气象观测资料,揭示了南极气候在近15—30年全球气候变化关键时期的最新动态及其对南极涛动变化的响应。结果显示,近15年来,位于南极半岛地区的长城站增暖趋势减缓且有变冷迹象,并伴随气压下降和降水增多的趋势,表明全球增暖停滞期南极半岛经历了与过去几十年长期趋势有所不同的新变化,而位于南极大陆沿海的中山站气象要素变化趋势相对平缓,表明南极半岛和南极大陆气候变化特征存在显著的区域性差异。两站多个气象要素与南极涛动指数显著相关,两站温度与南极涛动相关关系相反等研究事实说明了两站气候与南极涛动及其对应的大气环流区域特征有着密切的联系。 相似文献