A study of the possible extended influence of the ENSO phenomenon     

Cédric Gaucherel 《Comptes Rendus Geoscience》2004,336(3):175-185

El Niño/Southern Oscillation (ENSO) is well known to have a worldwide impact, in particular on streamflows. As an illustration, we found a good correlation (～0.47, 5-month time delay) between the ENSO activity and the discharge of the main rivers in French Guiana. However, this calculation was made between climatic and hydrological processes at ‘isolated precise moments’. Using a new method of time series analysis, we considered the ENSO and Atlantic Ocean/river discharge correlation integrated over time. This method shows, with more than 99% confidence level, new possible delayed and combined influences between the phenomena (respectively ～20 and 40 months for ENSO and Atlantic Ocean influences). To cite this article: C. Gaucherel, C. R. Geoscience 336 (2004).  相似文献   

罗布泊盐湖环状影像成因解释   总被引：14，自引：0，他引：14       下载免费PDF全文

谢连文  李锋  李兵海  全旭东 《沉积与特提斯地质》2004,24(4):76-80

根据遥感影像信息特征和盐湖气候变化模型，结合盐湖沉积特征和现代盐湖演化理论，通过对环状影像的成因进行解译和分析，将环状影像反映的1000年来盐湖气候变化的信息与北半球同期气候变化曲线对比，认为罗布泊盐湖是现代沉积形成的，是现代盐湖向干盐湖的演化历程中，由于气候冷暖交替变化而使盐湖沉积发生规律性变化的结果。  相似文献   

不同气候区月蒸散发能力计算模式适用性分析   总被引：9，自引：0，他引：9  

陈喜  姜丹 《水文》2004,24(5):1-4,40

根据实测气象资料和蒸散发量资料，对几种蒸散发量计算模式进行了对比分析，提出不同气候区计算模式的适用性。以彭曼一蒙蒂斯公式计算的蒸散发量作为参考值，得出Φ20蒸发皿换算成蒸散发能力的折算系数。分析成果对我国水文水资源计算和进行气候变化影响评价具有指导意义。  相似文献   

Controls on basalt terrace formation in the eastern Lesotho highlands     

Stefan Grab  Craig van Zyl  Nicholas Mulder 《Geomorphology》2005,67(3-4):473-485

The objective of this study is to ascertain the relative importance of lithological controls and geomorphological processes in the development of Drakensberg basalt terraces. Various hypotheses for terrace formation are considered, including geological controls, macroscale geomorphology, and climatic–geomorphological controls. The variations in strength and relative age differences for scarp surface exposures on two slopes of varying aspect are determined, so that a comparison can be made between various scarp outcrops and relative rates of weathering. Scarp outcrops were measured for their rock mass strength, rock surface roughness, and percentage lichen cover. The ethylene glycol test was performed on prepared rock samples to determine susceptibility to tensional breakup. A satellite image depicting the distribution of late-lying contemporary snow was used to assist in the construction of topo-climatic linkages with scarp terrace localities. Findings show that terraces are most common on southeast-facing aspects, and coincide with the major joint strike direction. Lithological factors are thus considered the primary control to such terrace development. It is suggested that a different set of geomorphological processes operates on various slope-altitudinal and slope-orientational positions at any given time.  相似文献   

Dryness-wetness change and regional differentiation of flood-drought disasters in Guangdong during 1480-1940AD     

ZHONG Wei  XUE Jibin  PENG Xiaoying  ZHAO Yinjuan 《地理学报》2005,15(3):286-292

Based on the historical records of the drought and flood disasters during 1480-1940AD, this paper reconstructs the sequences of wetness index (WI) and drought and flood disasters. We find a good identical relationship between the fluctuation of WI sequence and the δ18O record of the GISP2 ice core in Greenland, which shows an apparent monsoonal disposal pattern of moisture and temperature. By applying the Morlet Wavelet Transform Method to deal with the data, several apparent periodicities, such as 7-8a, 11-15a, 20-23a and ca 50a, are revealed, among which some can be attributed to the solar forcing. Based on results of Cluster Analysis of dry-wet changes, we resume the regional differentiation pattern of flood-drought disasters all over Guangdong during different climatic intervals in the LIA and, find the western and northern parts of Guangdong have undergone drastic changes in drought-flood regional differentiation, but the eastern part is relatively stable, and the area of the Pearl River Delta shows stable condition of more flood disasters.  相似文献   

沁水盆地石炭-二叠纪岩相古地理及聚煤作用研究   总被引：15，自引：0，他引：15  

邵龙义  杨书申  李卫军  肖正辉  陈江峰 《古地理学报》2005,7(4):535-548

晋东南沁水盆地是目前我国进行煤层气勘探开发的主要地区之一，煤层气储层主要是石炭系和二叠系的煤层，这些煤层气储层的厚度明显受沉积古地理控制。本文通过对露头及钻井剖面岩石学和沉积相研究,对该区主要含煤岩系-山西组和太原组进行了岩相古地理和煤储层聚集控制因素分析。太原组以石灰岩、铝土质泥岩、粉砂岩、粉砂质泥岩及砂岩为主，厚44.90～193.48 m，含多层可采煤层，总厚0～16.89 m，平均7.19 m，在太原组沉积期，研究区北部发育下三角洲平原相，煤层相对较厚，中部和南部为泻湖相，煤层相对较薄，东南角主要为滨外碳酸盐陆棚相，在晋城一带障壁砂坝相分布区，煤层亦较厚；山西组以砂岩、粉砂岩、泥岩为主，石灰岩仅在局部地区见到，该组厚18.60～213.25 m，含可采煤层1-2层，总厚0～10.0 m，平均4.20 m，在山西组沉积期，北部以下三角洲平原分流河道相为主，中部和南部以分流间湾相为主，东南部则以河口砂坝相为主，厚煤带都位于中部和南部三角洲分流间湾地区。总之，太原组富煤地带多与砂岩富集带相吻合，位于北部下三角洲平原和南部障壁砂坝地区，而山西组厚煤带大都位于南部三角洲分流间湾地区。  相似文献   

The Retreat of Tien Shan Glaciers (Kyrgyzstan) Since the Little Ice Age Estimated from Aerial Photographs, Lichenometric and Historical Data   总被引：2，自引：0，他引：2  

Olga Solomina  Roger Barry  Maria Bodnya 《Geografiska Annaler: Series A, Physical Geography》2004,86(2):205-215

The retreat of 293 glaciers in the Tien Shan Mountains (Kyrgyz Republic) from their maximum extent during the Little Ice Age (LIA) is estimated using aerial photographs from 1980 to 1985 and maps at a scale of 1:25000, constructed during period 1956–1990. Two indices of changes are used: the linear distance from the glacier terminus to its Little Ice Age moraine and the difference in absolute elevation of the terminus and the moraine. Historical information about the front positions of glaciers in the 1880s to the 1930s was used as an indirect control of remote sensing data. The age of moraines in key regions was estimated by lichenometry. On average, Tien Shan glaciers have retreated by 989 ± 540 m since the LIA maximum. Their front elevations (dh) rose by 151 ± 105 m. These changes are similar to changes observed in the Alps and western Norway, Pamir‐Alay and Koryak plateau, but greater than in east Siberia over the same interval. Differences between four regions in Tien Shan (northern, western, inner, central) are generally small, though in the northern Tien Shan the glacier retreat and frontal rise are more prominent (1065 ± 479 m and 215 ± 140 m, respectively).  相似文献   

祁连山区夏季总云量的气候变化与异常研究   总被引：3，自引：1，他引：3  

陈少勇董安祥  王丽萍孙秉强 《南京气象学院学报》2005,28(5):617-625

利用祁连山区周围34个测站的1961-2000年6—8月总云量资料，采用EOF、REOF、谱分析等方法，分析了40a来祁连山附近夏季总云量的空间异常特征和时间变化规律。结果表明：EOF的前3个主成分的累积方差占总方差的78％左右，可以较好地反映夏季总云量整体异常结构，即主体一致型、东南和西北变化相反型、东北和西南变化相反型。REOF的前3个主成分的累积方差占总方差的74％左右，前3个载荷向量场可以较好地代表夏季总云量的3个主要异常敏感区：祁连高原区、祁连东南区，河西走廊东部区，其相应的代表站是野牛沟、永登和民勤站。用代表站的资料分析3个异常区总云量的时间变化，其演变具有不同的趋势，但有相同的20a和10a周期。  相似文献   

Characteristics of an early Holocene climate and environment from lake sediments in Ebinur region, NW China   总被引：8，自引：0，他引：8  

WU Jinglu  SHEN Ji  WANG Sumin  JIN Zhangdong & YANG Xiangdong Nanjing Institute of Geography & Limnology  Chinese Academy of Sciences  Nanjing  China 《中国科学D辑(英文版)》2005,48(2):258-265

The characteristics of climatic environment in the early Holocene epoch were studied through analyzing environmental proxies from the sediments in the Ebinur Lake——a closed one in the arid region. The pollen assemblage and other geochemical indices showed that, the temperature was somewhat low in the period (8.0-11.5 cal kaBP) as a whole, but in the early period (11.5-10.6 cal kaBP) the temperature was higher, in company with more precipitation. In the conversion period from the early Holocene epoch to the middle Holocene epoch (8.9-8.0 cal kaBP) the climate fluctuated remarkably. Particularly the three layers of peat sediment revealed the strong instability of climate in the early Holocene epoch in the Ebinur region. All information on the development of peat and the experimental data of pollen and stable isotopes implied that, the climatic condition at 8.2, 8.6 and 10.5 cal kaBP was characterized by noticeable cold and humidness, and could be regarded as three cold and humid events in the early Holoc  相似文献   

我国西部地区过去2000年降水变化研究主要进展   总被引：2，自引：2，他引：2  

梁有叶  张德二 《气象科技》2004,32(3):137-142

概述最近10年来利用多种古气候代用记录研究我国西部地区距今2000年时段的降水(湿度)变化的主要进展。这些代用记录包括冰芯、树木年轮、湖泊沉积、黄土地层沉积和洞穴石笋等。综述利用这些代用资料建立的我国西部地区各地点的过去降水(湿度)气候序列，并对其所用方法、序列的分辨率等问题逐一说明。  相似文献