一个全球耦合模式的ENSO后报试验          下载免费PDF全文

YAN Li  YU Yong-Qiang  WANG Bin  LI Li-Juan  WANG Pan-Xing 《大气和海洋科学快报》2009,2(1):7-13

A group of seasonal hindcast experiments are conducted using a coupled model known as the Flexible Global Ocean-Atmosphere-Land System Modelgamil1.11 (FGOALS-g1.11) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG).Two steps are included in our ElNi o-Southern Oscillation (ENSO) hindcast experiments.The first step is to integrate the coupled GCM with the Sea Surface Temperature (SST) strongly nudged towards the observation from 1971 to 2006.The second step is to remove the SST nudging term.The authors carried out a one-year hindcast by adopting the initial values from SST nudging experiments from the first step on January 1st,April 1st,July 1st,and October 1st from 1982 to 2005.In the SST nudging experiment,the model can reproduce the observed equatorial thermocline anomalies and zonal wind stress anomalies in the Pacific,which demonstrates that the SST nudging approach can provide realistic atmospheric and oceanic initial conditions for seasonal prediction experiments.The model also demonstrates a high Anomaly Correlation Coefficient (ACC) score for SST in most of the tropical Pacific,Atlantic Ocean,and some Indian Ocean regions with a 3-month lead.Compared with the persistence ACC score,this model shows much higher ACC scores for the Ni o-3.4 index for a 9-month lead.  相似文献   

Coupled Model Simulations of Climate Changes in the 20th Century and Beyond   总被引：10，自引：1，他引：9  

YU Yongqiang  ZHI Hai  WANG Bin  WAN Hui  LI Chao  LIU Hailong  LI Wei  ZHENG Weipeng  ZHOU Tianjun 《大气科学进展》2008,25(4):641-654

Several scenario experiments of the IPCC 4th Assessment Report （AR4） are performed by version g1.0 of a Flexible coupled Ocean-Atmosphere-Land System Model （FGOALS） developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences （IAP/CAS）, including the ＂Climate of the 20th century experiment＂, ＂CO2 1% increase per year to doubling experiment＂ and two separate IPCC greenhouse gases emission scenarios AIB and B1 experiments. To distinguish between the different impacts of natural variations and human activities on the climate change, three-member ensemble runs are performed for each scenario experiment. The coupled model simulations show： （1） from 1900 to 2000, the global mean temper- ature increases about 0.5℃ and the major increase occurs during the later half of the 20th century, which is in consistent with the observations that highlights the coupled model＇s ability to reproduce the climate changes since the industrial revolution; （2） the global mean surface air temperature increases about 1.6℃ in the CO2 doubling experiment and 1.5℃ and 2.4℃ in the A1B and B1 scenarios, respectively. The global warming is indicated by not only the changes of the surface temperature and precipitation but also the temperature increase in the deep ocean. The thermal expansion of the sea water would induce the rise of the global mean sea level. Both the control run and the 20th century climate change run are carried out again with version g1.1 of FGOALS, in which the cold biases in the high latitudes were removed. They are then compared with those from version g1.0 of FGOALS in order to distinguish the effect of the model biases on the simulation of global warming.  相似文献   

Peak discharge increase in hyperconcentrated floods     

《Advances in water resources》2014

The peak of river floods usually decreases in the downstream direction unless it is compensated by freshwater inflow from tributaries. In the Yellow River (China) the opposite is regularly observed, where the peak discharge of river floods increases in the downstream direction (at a rate far exceeding the contribution from tributaries). This flood peak discharge increase is probably related to rapid morphological changes, to a modified bed friction, or to a combination of both. Yet the relative role of these processes is still poorly understood. This paper aims to analyze the relative contribution of bed erosion and friction change to the peak discharge increase, based on available data and a recently developed numerical model. Using this high-resolution, fully coupled morphodynamic model of non-capacity sediment transport, two hyperconcentrated floods characterized by downstream peak discharge increase are numerically reproduced and analyzed in detail. The results reveal that although erosion effects may contribute to the downstream discharge increase (especially in case of extreme erosion), for most cases the increase must be mainly due to a reduction in bed friction during peak discharge conditions. Additionally, based on the concept of channel storage reduction, the effects of decreasing bed friction and (very strong) bed erosion can be integrated in explaining the peak discharge increase.  相似文献   

Coupled ESR and U-series dating of early Pleistocene Gigantopithecus faunas at Mohui and Sanhe Caves,Guangxi, southern China     

《Quaternary Geochronology》2015

Several caves of the Guangxi Zhuang Autonomous Region, southern China, have delivered Gigantopithecus blacki remains, an extinct Pleistocene giant ape, in association with abundant mammalian faunas. To determine their geological ages, fossil teeth from Mohui and Sanhe Caves were dated using the coupled ESR/U-series method. The teeth from Mohui Cave gave age estimates of 1.69 ± 0.22 Ma and 1.29 ± 0.11 Ma. The Sanhe Cave samples had age estimates ranging from 910 ± 200 ka to 600 ± 150 ka with error weighted mean ages of 890 ± 130 ka and 720 ± 90 ka for the layers 5 and 4, respectively. Our results and previous paleomagnestism data place the Gigantopithecus fauna at Mohui Cave between Olduvai and Jaramillo subchrons and suggest that it was coeval with Chuifeng, Longgupo and Liucheng assemblages. The Sanhe fauna is younger, of late early Pleistocene age, and can be dated to the period between Jaramillo subchron and B/M boundary.  相似文献   

IPCC AR4多模式对中国地区未来40 a雪水当量的预估   总被引：3，自引：2，他引：1  

王芝兰  王澄海 《冰川冻土》2012,34(6):1273-1283

通过评估参加CMIP3计划的22 个GCM在20 世纪气候情景(20C3M)下中国地区雪水当量模拟能力的检验, 挑选出模拟能力较好的模式, 通过多模式集合方法, 对SEARS的模拟结果进行集合, 预估未来40 a雪水当量在中国地区的时空变化特征.结果表明: 在A1B情景下和B1情景下, 中国地区未来40 a雪水当量年际变化均呈减少趋势; 在A1B和B1情景下, 青藏高原地区、 华北平原地区、 长江中游地区及东北北部地区的雪水当量均呈减少趋势, 其中在昆仑山西段帕米尔高原地区减少最为显著, 其次为喜马拉雅山区和巴颜喀拉山东段地区.在中国北部的内蒙古高原地区、 云贵高原等部分地区的雪水当量则有所增加.总体上, A1B情景下比B1情景下雪水当量的减少更为明显. 2021-2050年雪水当量在青藏高原减少显著; 对于季节变化来说, 在秋冬季积雪的累积期, 雪水当量可能增加, 尤其在10-12月, 而在积雪消融的春夏季(2-6月)有所减少.  相似文献   

A sensitivity analysis of Hortonian flow   总被引：6，自引：0，他引：6  

J.-O. Delfs  C.-H. Park  O. Kolditz   《Advances in water resources》2009,32(9):1386-1395

We present a sensitivity analysis for infiltration excess (Hortonian) overland flow based on a classic laboratory experiment by Smith and Woolhiser [Smith RE, Woolhiser DA. Overland flow on an infiltrating surface. Water Resour Res 1971;7(4):899–913]. The model components of the compartment approach are comprised of a diffusive wave approximation to the Saint–Venant equations for overland flow, a Richards model for flow in the variably saturated zone, and an interface coupling concept that combines the two components. In the coupling scheme a hydraulic interface is introduced to allow the definition of an exchange flux between the surface and the unsaturated zone. The effects of friction processes, soil capillarity, hydraulic interface, and vertical soil discretization on both infiltration and runoff prediction are investigated in detail. The corresponding sensitivity analysis is conducted using a small-perturbation method. As a result the importance of the hydraulic processes and related parameters are evaluated for the coupled hydrosystem.  相似文献   

流体涡旋中螺旋波不稳定发展的理论研究   总被引：3，自引：0，他引：3       下载免费PDF全文

陶建军  李朝奎 《地球物理学报》2008,51(3):650-656

文章利用柱坐标下的流体涡度方程,通过求初始时刻的解析解,研究了螺旋波的不稳定发展问题.结论是：涡旋中螺旋波动之间可以通过基本流耦合相互作用,出现共振不稳定增长.其增长率大小与初始扰动的波数相关,数值计算结果也表明：波动在发展过程中,螺旋带状结构将越来越明显,螺旋角越来越小.  相似文献   

World continental modeling for water resources using system dynamics     

Toshiharu Kojiri  Tomoharu Hori  Junpei Nakatsuka  Teng-Sheng Chong 《Physics and Chemistry of the Earth》2008,33(5):304-311

This research assesses the severity of future water scarcity and its impact on the growth of human civilization through system dynamics modeling of the world at regional level. Six sectors of activities are modeled in each continent to represent the human society. Continental interactions such as migration and trade are also modeled to express the synergy of activities among the various continents. Results of the model simulations from 1960 to 2100 show that water scarcity, unlike other limitations such as nonrenewable resources and persistent pollution, gives severe, detrimental problems within short delays after its occurrence.  相似文献   

钾长石在碱性条件下的蚀变机制及其蚀变产物托贝莫来石的纳米结构研究     

翟媛媛  曾庆栋  HELLMANN Rolan  刘善科  刘建明  南景博 《岩石学报》2020,36(9):2834-2844

钾长石在碱性流体蚀变过程中会形成层状铝硅酸盐等矿物,前人对其反应机制和反应产物进行了研究,但缺乏微观尺度尤其是纳米尺度的探讨。因此,作者对钾长石在极端碱性条件下(190℃,24h,初始p H=12.4)的蚀变机制及其蚀变产物层状硅酸盐托贝莫来石的显微结构开展了纳米尺度的研究。X射线粉末衍射、扫描电子显微镜、能量色散光谱等观测结果显示,钾长石在碱性条件下水热蚀变所得到的产物主要为托贝莫来石、水钙铝榴石和方解石。高分辨率的透射电镜结果表明,在钾长石与次生矿物相的界面形成了纳米级的多孔非晶质层,且在空间上表现出结构的不连续性。界面溶解-再沉淀(CIDR)机制很好地解释了钾长石与次生矿物相界面的空间不连续性和非晶质层的形成。对蚀变产物中纤维状的托贝莫来石晶体进行显微结构表征,结果表明托贝莫来石的孔隙直径为0～160nm,平均孔径约为40nm;其构成的纳米孔隙和通道有利于增加周围流体中离子和气体的溶解度,并可能会影响局部化学平衡。这为层状铝硅酸盐作为自然界以及工业吸附材料和催化剂的更广泛应用提供了重要依据。  相似文献   

元素活动态提取条件和分析方法的应用研究   总被引：1，自引：0，他引：1  

徐进力  邢夏  张鹏鹏  胡梦颖  白金峰  张勤  王学求 《地质学报》2020,94(3):982-990

元素活动态分析作为深穿透地球化学的新方法,得到了广泛的应用。实验对水提取态、黏土吸附态、有机结合态和铁锰氧化物结合态四种元素活动态的提取条件进行了系统研究,分别考察了提取时间、液固比、离心转速、提取液放置时间对提取效果的影响,确定了元素活动态的最佳提取条件:提取时间为24h,液固比为10:1,离心转速4000rpm;提取液采用新型的高分辨率等离子体质谱法(HR-ICP-MS)测定,该仪器具有强大的动态线性范围(10-12~1012)和高灵敏度,使可同时测定的元素拓展至50余种,可以大大提高工作效率。对HR-ICPMS的主要工作条件:辅助气流量、样品气流量和采样深度等利用响应面法进行了优化。本法将传统的过滤法改为离心法,避免了滤纸或穿滤引入的误差;将新型的高分辨率等离子体质谱法(HR-ICP-MS)应用到提取液的测定,提升了多元素同时分析能力,大大提高工作效率,同时也降低了该方法的检出限,改善了测定结果的精密度。依据实验结果,建立了HR-ICP-MS对四种元素活动态的分析方法,分别得到了四种活动态中各元素的方法检出限和方法精密度,水提取态、黏土吸附态、有机结合态和铁锰氧化物结合态中各元素的精密度范围依次为3.4%~38.1%、3.78%~35.7%、2.41%~35.9%、2.26%~32.5%;通过顺序提取,将四个相态中提取到的元素量和残渣中残留进行加和,得到50个元素的加和结果,验证了该方法的准确度(RE)为-29%^-1.3%,满足当前元素活动态的分析测试需求。  相似文献