Evolution of permafrost in China during the last 20 ka     

Jin  Huijun  Jin  Xiaoying  He  Ruixia  Luo  Dongliang  Chang  Xiaoli  Wang  Shaoling  Marchenko  Sergey S  Yang  Sizhong  Yi  Chaolu  Li  Shijie  Harris  Stuart A 《中国科学:地球科学(英文版)》2019,62(8):1207-1223

The formation and evolution of permafrost in China during the last 20 ka were reconstructed on the basis of large amount of paleo-permafrost remains and paleo-periglacial evidence, as well as paleo-glacial landforms, paleo-flora and paleofauna records. The results indicate that, during the local Last Glacial Maximum(LLGM) or local Last Permafrost Maximum(LLPMax), the extent of permafrost of China reached 5.3×106-5.4×106 km2, or thrice that of today, but permafrost shrank to only0.80×106-0.85×106 km2, or 50% that of present, during the local Holocene Megathermal Period(LHMP), or the local Last Permafrost Minimum(LLPMin). On the basis of the dating of periglacial remains and their distributive features, the extent of permafrost in China was delineated for the two periods of LLGM(LLPMax) and LHMP(LLPMin), and the evolution of permafrost in China was divided into seven periods as follows:(1) LLGM in Late Pleistocene(ca. 20000 to 13000-10800 a BP)with extensive evidence for the presence of intensive ice-wedge expansion for outlining its LLPMax extent;(2) A period of dramatically changing climate during the early Holocene(10800 to 8500-7000 a BP) when permafrost remained relatively stable but with a general trend of shrinking areal extent;(3) The LHMP in the Mid-Holocene(8500-7000 to 4000-3000 a BP)when permafrost degraded intensively and extensively, and shrank to the LLPMin;(4) Neoglaciation during the late Holocene(4000-3000 to 1000 a BP, when permafrost again expanded;(5) Medieval Warming Period(MWP) in the late Holocene(1000-500 a BP) when permafrost was in a relative decline;(6) Little Ice Age(LIA) in the late Holocene(500-100 a BP), when permafrost relatively expanded, and;(7) Recent warming(during the 20 th century), when permafrost continuously degraded and still is degrading. The paleo-climate, geography and paleopermafrost extents and other features were reconstructed for each of these seven periods.  相似文献   

黄河龙头水库来水量的年代际变化及年度预测方法          下载免费PDF全文

汤懋苍  张拥军  李栋梁 《气候变化研究进展》2005,1(3):129-132

根据1736-2004年近270 a来的代用资料和实测资料,对唐乃亥水文站逐年来水量划分为9个丰水年段,8个枯水年段。在同时段的太阳黑子周期长度（SCL）资料中,找到9个SCL的极长点,8个SCL的极短点,发现SCL的极长（短）点都出现在丰（枯）水年段之中或超前1～2 a。这为黄河源区丰、枯水段的预测找到了一个比较好的指标。最后,从"宇地磁耦合假说"出发,解释其关系密切的物理原因。  相似文献   

近50年中国冬季大地冷涡与春夏季干旱相关的统计   总被引：2，自引：1，他引：1  

汤懋苍  张拥军  李栋梁 《气象学报》2005,63(6):1006-1009

通过对冬季大地冷涡与春夏季干旱的相关分析,发现:除高原主体外,冬季的大地冷涡对应着春夏季为干旱少雨区;而且大地冷涡东面的地冷涡绝大多数也是春夏季的干旱少雨区。冬季大地冷涡在中国的出现频率为80%,可作为短期气候预测的重要因子。  相似文献   

Climate variability and predictability associated with the Indo-Pacific Oceanic Channel Dynamics in the CCSM4 Coupled System Model     

袁东亮  徐鹏  徐腾飞 《中国海洋湖沼学报》2017,35(1):23-38

An experiment using the Community Climate System Model (CCSM4), a participant of the Coupled Model Intercomparison Project phase-5 (CMIP5), is analyzed to assess the skills of this model in simulating and predicting the climate variabilities associated with the oceanic channel dynamics across the Indo-Pacific Oceans. The results of these analyses suggest that the model is able to reproduce the observed lag correlation between the oceanic anomalies in the southeastern tropical Indian Ocean and those in the cold tongue in the eastern equatorial Pacific Ocean at a time lag of 1 year. This success may be largely attributed to the successful simulation of the interannual variations of the Indonesian Throughflow, which carries the anomalies of the Indian Ocean Dipole (IOD) into the western equatorial Pacific Ocean to produce subsurface temperature anomalies, which in turn propagate to the eastern equatorial Pacific to generate ENSO. This connection is termed the “oceanic channel dynamics” and is shown to be consistent with the observational analyses. However, the model simulates a weaker connection between the IOD and the interannual variability of the Indonesian Throughflow transport than found in the observations. In addition, the model overestimates the westerly wind anomalies in the western-central equatorial Pacific in the year following the IOD, which forces unrealistic upwelling Rossby waves in the western equatorial Pacific and downwelling Kelvin waves in the east. This assessment suggests that the CCSM4 coupled climate system has underestimated the oceanic channel dynamics and overestimated the atmospheric bridge processes.  相似文献   

山东洞体应变观测质量分析     

李希亮  卢双苓  赵小贺  孟建国  李栋梁 《地震地磁观测与研究》2014,35(5):196-201

选取山东省3个洞体应变台2007-2011年观测数据,分析资料的完整性、内在质量及干扰因素.结果表明：①观测资料连续性和完整性较好;②仪器零漂满足设计指标要求;③M2波振幅因子相对误差和相对噪声水平达到Ⅰ类应变台标准;④仪器更新后观测质量提升;⑤洞体应变观测主要受仪器调修、气压、降雨和观测环境变化等因素影响.  相似文献   

基于CMIP5多模式集合资料的中国气温和降水预估及概率分析   总被引：4，自引：1，他引：3  

杨绚  李栋梁  汤绪 《中国沙漠》2014,34(3):795-804

选用国际耦合模式比较计划第五阶段（CMIP5）提供的30个全球大气-海洋耦合模式（AOGCMs）在典型浓度路径（RCPs）情景下气温和降水量的预估结果,采用扰动法,用站点观测资料作为气候背景场替代AOGCM模拟的气候平均,尝试校正气候预估结果的系统性偏差。通过集合方法,用概率的形式给出中国平均气温升高1 ℃,2 ℃和3 ℃以及降水量增加10%,20%和30%概率的空间分布,讨论了中国未来平均气温和降水量可能的变化。结果表明：经过扰动法处理后的气温和降水量预估集合保留了当前气候的局地信息。预估平均气温在中国均有上升,北方地区尤其是青藏高原地区变暖的程度大于南方地区,北方大部分地区平均气温升高的趋势为0.28 ℃/10a。在21世纪初,中国北方地区年平均气温升高1 ℃的可能性超过50%。到了21世纪末期,中国大部分地区平均气温升高2 ℃的可能性超过60%,新疆北部以及青藏高原南部地区气温升高3 ℃的可能性超过50%。预估中国降水量普遍增多,中国北方地区降水量增多的程度要明显大于江淮流域及其以南地区,尤其是西北地区降水量增多非常显著,降水量增多30%的可能性超过70%以上。  相似文献   

The comparison of altimeter retrieval algorithms of the wind speed and the wave period   总被引：3，自引：3，他引：0  

ZHAO Dongliang  LI Shuiqing  SONG Chaoyang 《海洋学报(英文版)》2012,31(3):1-9

With the launch of altimeter,much effort has been made to develop algorithms on the wind speed and the wave period.By using a large data set of collocated altimeter and buoy measurements,the typical wind speed and wave period algorithms are validated.Based on theoretical argument and the concept of wave age,a semi-empirical algorithm for the wave period is also proposed,which has the wave-period dimension,and explicitly demonstrates the relationships between the wave period and the other variables.It is found that Ku and C band data should be applied simultaneously in order to improve either wind speed or wave period algorithms.The dual-band algorithms proposed by Chen et al.(2002) for the wind speed and Quilfen et al.(2004) for the wave period perform best in terms of a root mean square error in the practical applications.  相似文献   

业务协同视角下基于GIS的“五规融合”平台   总被引：2，自引：1，他引：1  

陈真  王萌  张栋梁 《测绘通报》2017,(7):124-128

以建立统一空间规划体系为目标,近年来全国各地相继开展了多规融合探索。要从根本上解决多规融合问题,核心是要解决多规涉及部门间的业务协同。本文基于业务协同研究,结合珠海市实际,探索提出了“五规融合”数据共享、规划编制协同、项目策划生成等业务协同机制,并以GIS技术为基础,对“五规融合”平台建设的设计思路与功能实现进行了探讨。  相似文献   

湖南省慈利县农作物富硒程度调查评价与富硒农业发展建议     

翁进  李榕  孙元贵  黄栋良  何梓华  罗治勇 《国土资源导刊(湖南)》2017,14(1)

针对慈利县重点区域进行了农作物富硒程度专项调查,通过建立湖南省相关农作物富硒标准,发现采集的十种农作物中大部分达到富硒标准,其中油菜、水稻、玉米等硒平均含量最高,分别达到0.285mg/kg、0.136 mg/kg以及0.118 mg/kg。通过对比根系土硒含量,研究了十种作物硒富集规律,得出了各农作物硒富集系数,油菜硒富集能力最强,其次为大豆、大蒜。针对慈利县土壤、农作物含硒量特征提出了慈利县富硒农业发展的建议。  相似文献   

山东莱芜接触交代—热液铁矿矿体形态研究   总被引：1，自引：0，他引：1  

宗信德  贾东亮  刘超  尹承亮  刘纪涛  王建 《山东国土资源》2010,26(11)

在对莱芜接触交代铁矿地质特征研究中发现以往地质报告在矿体连接上存在混乱,使矿体形态失真。为便于今后矿体对比和成矿规律的认识,提出了矿体形态分类原则,并以三分法对矿体形态进行分类。指出矿体产状变化是矿体膨胀收缩、分支复合和尖灭再现的结果。根据矿体形态分类指出了找矿方向。不同的矿体形态反映不同的控矿构造,反映不同的矿体规模,反映不同的成矿岩体形态产状。单斜缓倾矿体的成矿岩体是岩床,控矿较小;陡倾矿体和背向斜矿体的成矿岩体是岩盖,控矿较大。  相似文献