Lake-expanding events in the Tibetan Plateau since 40 kaBP     

Jia  Yulian  Shi  Yafeng  Wang  Sumin  Jiang  Xuezhong  Li  Shijie  Wang  Aijun  Li  Xusheng 《中国科学:地球科学(英文版)》2001,44(1):301-315

Since 40 kaBP, the current endorheism on the Tibetan Plateau had experienced at least four lake-explanding events, at 40-28 kaBP, 19-15 kaBP, 13-11 kaBP, 9.0-5.0 kaBP, respectively. The 40-28 kaBP and 9.0-5.0 kaBP lake-expanding events, corresponding to the global warming periods, were mainly determined by the abundant summer monsoon rainfall brought by strong Indian monsoon, aroused by enhanced solar radiation at earth orbital precessional cycle. The 40-28 kaBP lake-expanding event, also called the great lake period or the pan-lake period, for several great lake groups had come into being by the interconnection of the presently isolated and closed lake catchments. The total lake area over the Tibetan Plateau was estimated at least up to 150000 km², 3.8 times of the present, and the lake supply coefficients were about 3–10. The 9.0-5.0 kaBP lake-expanding, with a total lake area of 68000 km², less than the above mentioned reflected the Indian monsoon rainfall less than that of 40-28 kaBP. The expanded lakes at 19-15 kaBP and 13-11 kaBP, distributed in these basins with more or less existing glacial, indicated plenty of glacial meltwater discharged to balance evaporation on expansive lake surface. At the same time, the enhanced precipitation by the westerlies at 19-15 kaBP and by Indian monsoon at 13-11 kaBP plays an important role in maintaining the high lake level. Heinrich events greatly affected the evolution of climate system over the Tibetan Plateau, and thus gave a clear boundary of the high lake level change in the late Quaternary.

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Relation between δ18O in atmospheric precipitation and temperature and precipitation     

Xinping Zhang  Yafeng Shi  Tandong Yao 《中国地理科学(英文版)》1995,5(4):289-299

The paper analyzes the relation between δ¹⁸O and temperature and precipitation in different regions of the world on the basis of the data from the global observational network set by the International Atomic Energy Agency (I-AEA) and the World Meteorological Organization (WMO). The results show that there is the marked positive correlation between δ¹⁸O and temperature in the mid-high latitude continent regions, and the marked negative correlation between δ¹⁸O and precipitation in the mid-low-latitude ocean and coast stations.  相似文献   

Climate variation since the Last Interglaciation recorded in the Guliya ice core   总被引：21，自引：2，他引：21  

Tandong Yao  L. G. Thompson  Yafeng Shi  Dahe Qin  Keqin Jiao  Zhihong Yang  Lide Tian  E. M. Thompson 《中国科学D辑(英文版)》1997,40(6):662-668

The climatic and environmental variations since the Last Interglaciation are reconstructed based on the study of the upper 268 m of the 309-m-long Guliya ice core. Five stages can be distinguished since the Last Interglaciation from the δ¹⁸O record in the Guliya ice core: Stage 1 (Deglaciation), Stage2 (the Last Glacial Maximum), Stage 3 (interstadial), Stage 4 (interstadial in the early glacial maximum) and Stage 5 (the Last Interglaciation). Stage 5 can be divided further into 5 substages; a, b, c, d, e. The δ¹⁸O record in the Guliya ice core indicates clearly the close correlation between the temperature variation on the Tibetan Plateau and the solar activities. The study indicates that the solar activity is a main forcing to the climatic variation on the Tibetan Plateau. Through a comparison of the ice core record in Guliya with that in the Greenland and the Antarctic, it can be found that the variation of large temperature variation events in different parts of the world is generally the same, but the variation amplitude of temperature is different. Project supported by thc Climbing Program of the State Eighth Five-Year Plan and the National Natural Science Foundation of China.  相似文献   

冰川及其径流对气候变化响应过程的模拟模型——以乌鲁木齐河源1号冰川为例   总被引：2，自引：0，他引：2  

叶佰生  陈克恭  施雅风 《地理科学》1997,(1)

用冰川动力模型对乌鲁木齐河源１号冰川东支进行模拟计算结果表明：１号冰川东支在维持目前的气候变化水平下还将继续退缩到约１６００ｍ长度；若气温升高１℃，１号冰川将退缩为约只有３００ｍ长的悬冰川。随着冰川退缩，冰川冷却作用减弱，冰川区的升温将高于非冰川区。１号冰川目前的冰川径流是处在一个高值期（相对于它的稳定状态），若气候继续变暖，冰川径流还将继续增大，达到一峰值后将迅速减小。  相似文献   

甘孜黄土与青藏高原冰冻圈演化   总被引：8，自引：1，他引：8  

方小敏  陈富斌 《冰川冻土》1996,18(3):193-200

逐样系统交变退磁磁性测量表明，８６ｍ的甘孜黄土剖面形成于约８１．８４×１０＾４ａ ＢＰ前。剖面中黄土石英砂类型分析揭示出至少约８１．８４×１０＾４ａ ＢＰ以前，高原已进入冰冻圈，并且很快于约７６×１０＾４ ａＢＰ前冰川规模达到最大，并持续至约５３×１０＾４ｑａ ＢＰ前，倒数第二次冰川规模次之，然后冰川规模明显减少。  相似文献   

数字海图水深注记的自动选取     

黄亚锋  艾廷华  张航峰 《测绘科学》2016,41(6):28-33

水深注记作为表示海底地形地貌特征的主要制图要素,它的正确选取对于保证航海安全、反映海底地貌起伏具有重要意义。针对传统的水深注记方法,该文提出一种顾及多重约束条件的水深注记选取方法。在总结水深注记综合约束条件基础上,以Vononoi图为支撑几何构造,对水深注记综合涉及的地形特征、空间分布特征、邻近特征3个方面的综合约束进行了形式化定义;借鉴人工选取的思想,在水深综合约束条件重要性排序的基础上,通过反映地形、空间分布、邻近关系等主体特征的重要水深的依次选取,以及背景水深的抽稀实现水深注记选取;最后以实测数据进行实验,验证该方法的有效性。  相似文献   

Evidence for a warm-humid climate in arid northwestern China during 40–30 ka BP     

Bao Yang  Yafeng Shi  Achim Braeuning  Jianxun Wang 《Quaternary Science Reviews》2004,23(23-24):2537-2548

Former shorelines and sedimentary records from several lake basins in northwestern China (Xinjiang, Qinghai) give evidence for warm and humid climatic conditions during 40–30 ka BP. Further indications of this favorable climate period are derived from palaeosols from the Ili loess and from cemented calcareous layers on the terraces of the Keriya River at the southern margin of the Tarim Basin and in the Badain Jaran Desert in Inner Mongolia. At that time, annual mean temperature in the Qaidam Basin was 2 °C higher and in the western part of Inner Mongolia even 2–3 °C higher than today. Precipitation in most parts of northwestern China was between 60–300 mm greater than today. These changes were probably a consequence of an increase in ocean surface temperature and evaporation resulting from a higher radiation input at middle and low latitudes caused by changes in the Earth's precessional cycle. As a result of these orbital changes, it is suggested that the intensified westerly circulation was responsible for increased moisture over northwestern China.  相似文献   

Decadal climatic variations recorded in Guliya ice core and comparison with the historical documentary data from East China during the last 2000 years     

Yafeng Shi  Tandong Yao  Bao Yang 《中国科学D辑(英文版)》1999,42(1):91-100

The high-resolution records of δ¹⁸O and snow accumulation variations from the Guliya ice core provide valuable data for research on climatic variations at a decadal resolution during the past 2000 years in China. Based on the ice core data, five spells have been divided: the warm and wet period before 270 AD, the cold and dry period between 280 and 970 AD, the moderate and dry period between 970 and 1510 AD, the well-defined” Little Ice Age “with drastic cold-warm fluctuations between 1510 and 1930 AD and the warming period since 1930 AD. According to the combination of temperature and precipitation, cold events (55 times) surpass warm ones (26 times), and dry events (55 times) slupass wet ones (45 times). Cold-wet events (14 times) are less than cold-dry ones (16 times), while warm-wet events (10 times) are more than warm-dry ones (4 times). If the difference of2%c in δ¹⁸O (corresponding to 3K in temperature) between two or three adjacent decades is taken as the criterion of it, the abrupt change has taken place 33 times or so since the 3rd century. Among them are four large ones, occurring in 250–280, 550–580, 1220–1260, and 1520–1560 AD respectively. Comparison of the ice core data with the latest comprehensive research results on historical documents of East China shows that the great climatic events appeared simultaneously or at the same age in the ice core record and in the documentary data, suggesting that consistences and similarities in climatic variation among different areas are far away from each other in the lower to mid-latitudes. However, there is a great difference between them during the Medieval Warm Period, which is conspicuous in the historical documents but not in the ice core. In addition, the first cold event of the Little Ice Age on East China was 60 years earlier than that of the Guliya Ice Cap, when the degree of cwling in West China is more intensive than that of East China. But the third cold event in East China lagged behind that in West China during the late 19th century. The 1820s cold event in both West and East China may be caused by the magnificent Tambora volcanic eruption in 1815  相似文献   

我国煤矿坑道钻探装备技术进展与展望          下载免费PDF全文

姚宁平  姚亚峰  方鹏  田宏亮  郝世俊  梁春苗  张幼振 《探矿工程》2021,48(1):81-87

煤矿坑道钻探装备技术在发展过程中受到诸多不利条件的限制,导致新技术发展滞后,随着我国煤矿大力推进智能化建设,给煤矿坑道钻探装备技术带来了革命性的发展机遇。通过分析了国外坑道钻探装备的技术特点和发展状况,以及国内坑道钻探装备技术的三个阶段发展,包括初级阶段的分体式钻机与稳定组合钻具轨迹控制方法,蓬勃发展阶段的履带式钻机、定向钻进装备技术及松软煤层钻进技术,新发展阶段的自动化和智能化装备技术,提出了今后我国煤矿智能化发展阶段钻探装备技术需要解决的关键问题,为推进钻探装备技术的智能化水平提高提供支撑。  相似文献   

利用SBAS-InSAR技术监测菏泽市地面沉降     

张亚凤  刘国林  牛冲  陈洋  周一鸣 《大地测量与地球动力学》2022,42(11):1184-1190

采用SBAS-InSAR技术对菏泽市65景Sentinel-1A SAR数据进行处理,获取菏泽市2017-05-20~2021-05-23的沉降结果,并结合地下煤矿工作面的开采对各成像时期的地面沉降情况进行精细化分析,最后利用实际水准数据对SBAS-InSAR监测结果进行精度验证。结果表明,研究时段内,菏泽市地面沉降不断加速,郓城地区沉降较为严重,最大年平均沉降速率达-311 mm/a,最大累积沉降量达-1 269 mm。SBAS-InSAR监测到的沉降位置和沉降变化趋势与水准测量结果相符,但在沉降严重区域,SBAS-InSAR监测到的沉降量与实际水准测量结果有一定差异。  相似文献