Preliminary evaluations of FGOALS-g2 for decadal predictions   总被引：3，自引：0，他引：3  

王斌  刘咪咪  俞永强  李立娟  林鹏飞  董理  刘利  刘骥平  黄文誉  徐世明  申思  普业  薛巍  夏坤  王勇  孙文奇  胡宁  黄小猛  刘海龙  郑伟鹏  吴波  周天军  杨广文 《大气科学进展》2013,30(3):674-683

The Flexible Global Ocean-Atmosphere-Land System model, Grid-point Version 2 (FGOALS-g2) for decadal predictions, is evaluated preliminarily, based on sets of ensemble 10-year hindcasts that it has produced. The results show that the hindcasts were more accurate in decadal variability of SST and surface air temperature (SAT), particularly in that of Nin o3.4 SST and China regional SAT, than the second sample of the historical runs for 20th-century climate (the control) by the same model. Both the control and the hindcasts represented the global warming well using the same external forcings, but the control overestimated the warming. The hindcasts produced the warming closer to the observations. Performance of FGOALS-g2 in hindcasts benefits from more realistic initial conditions provided by the initialization run and a smaller model bias resulting from the use of a dynamic bias correction scheme newly developed in this study. The initialization consists of a 61-year nudging-based assimilation cycle, which follows on the control run on 01 January 1945 with the incorporation of observation data of upper-ocean temperature and salinity at each integration step in the ocean component model, the LASG IAP Climate System Ocean Model, Version 2 (LICOM2). The dynamic bias correction is implemented at each step of LICOM2 during the hindcasts to reduce the systematic biases existing in upper-ocean temperature and salinity by incorporating multi-year monthly mean increments produced in the assimilation cycle. The effectiveness of the assimilation cycle and the role of the correction scheme were assessed prior to the hindcasts.  相似文献   

Long-term behaviors of two versions of FGOALS2 in preindustrial control simulations with implications for 20th century simulations   总被引：2，自引：0，他引：2  

林鹏飞  刘海龙  俞永强  周天军 《大气科学进展》2013,30(3):577-592

Climate drift in preindustrial control (PICTL) simulations can lead to spurious climate trends and large uncertainties in historical and future climate simulations in coupled models. This study examined the long-term behaviors and stabilities of the PICTL simulations in the two versions of FGOALS2 (the Flexible Global Ocean-Atmosphere-Land System model Version 2), which have been submitted to the Coupled Model Inter-comparison Project Phase 5 (CMIP5). As verified by examining time series of thermal fields and their linear trends, the PICTL simulations showed stable long-term integration behaviors and no obvious climate drift [the magnitudes of linear trends of SST were both less than 0.04oC (100 yr)-1] over multiple centuries. The changed SSTs in a century (that corresponded to the linear trends) were less than the standard deviations of annual mean values, which implied the internal variability was not affected. These trend values were less than 10% of those of global averaged SST from observations and historical runs during the periods of slow and rapid warming. Such stable long-term integration behaviors reduced the uncertainty of the estimation of global warming rates in the historical and future climate projections in the two versions of FGOALS2. Compared with the trends in the Northern Hemisphere, larger trends existed in the SST and sea ice extents at the middle to high latitudes of the Southern Hemisphere (SH). To estimate the historical and future climate trends in the SH or at some specific regions in FGOALS2, corrections needed to be carried out. The similar long-term behaviors in the two versions of FGOALS2 may be attributed to proper physical processes in the ocean model.  相似文献   

两种热通量边界条件对热带太平洋海温模拟的影响     

王璐  周天军  刘海龙  邹立维 《海洋学报(英文版)》2011,30(4):9-18

利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室发展的气候海洋模式(LICOM),考察了两种热通量边界条件(牛顿冷却型边界条件和总体公式型边界条件)对热带太平洋海温平均态和年际变率模拟效果的影响。结果显示,在两种边界条件下,模式均能较好的再现海温的年平均空间分布特征和季节循环特征。对比分析发现,在牛顿冷却条件下,模拟结果与观测更加接近,这是因为该条件会通过调整净海表热通量使模拟海温向观测的气候态海温逼近。就年际变率而言,牛顿冷却条件下模式模拟的净海表热通量负反馈作用偏强,从而使ENSO模拟偏弱,进而使中东太平洋的异常经向温度平流模拟偏弱,造成海温异常的经向尺度偏窄。负反馈的强度与耦合系数的选取有关。而总体公式条件下模式能够合理地模拟出ENSO相关的热通量负反馈过程,从而能正确的模拟出ENSO振幅以及ENSO空间型。因此,当利用海洋模式对气候平均态海温进行模拟时,两种条件均可采用,但以牛顿冷却条件为佳;而当对海温的年际变率进行模拟时,应该采用总体公式型边界条件。  相似文献   

基于GIS的中原城市群交通网络优化   总被引：1，自引：1，他引：0  

刘静玉  刘海龙  周国众 《地理空间信息》2011,(6):24-26

交通网络是城市群发育的先决条件和重要手段。利用GIS技术在评价中原城市群交通网络可达性的基础上,认为在城市群建设中应注重交通网络整合,适度超前发展并完善交通网络体系,并提出城市群交通网络优化设计的具体方案。  相似文献   

道路网智能选取的案例类比推理法   总被引：1，自引：1，他引：0  

郭敏  钱海忠  黄智深  何海威  刘海龙 《测绘学报》2014,(7)

从人类学习和认知角度,借鉴人工智能领域基于案例推理学习的成果,提出一种基于案例类比推理的道路网智能选取新方法。该方法将制图专家对某区域道路网的交互选取结果作为参考标准,对其进行结构化描述并构建和转化为案例库;计算机采用一定的简化算法和泛化算法对该案例库进行分析和学习,获取检索效率更高和适应样本能力更强的案例模型库;计算机在对相似道路网自动选取时,根据获取的案例模型库,采用基于案例类比推理的方法,分析获取相应的解决方案,进而完成道路网智能选取。与已有研究成果相比,本方法以案例及其泛化模型来模拟专家思维,以计算机对案例模型的类比学习来进行相似道路网自动选取,增强了道路网选取中的智能性。最后对本方法的科学性和适用性进行验证,并对试验结果作分析和评价,同时指出了存在的问题和进一步的研究方向。  相似文献   

天水围：水泥森林的另一面     

庄立彬  刘海龙 《地图》2014,(3):44-51

天水围位处新界西北、深圳湾南岸,是香港第三代的新市镇。新市镇以天华路为界,分南北两期发展：20世纪90年代开始发展第一期“天水围南”,包括多个公共屋邮及私人屋苑嘉湖山庄等;第二期“天水围北”的开发则在1998年开始。  相似文献   

面状居民地匹配骨架线傅里叶变化方法     

黄智深  钱海忠  郭敏  刘海龙  王骁 《测绘学报》2013,(6):913-921,928

大比例尺城市居民地是变化最为活跃的要素之一,因其形态复杂多样,数据量密集,匹配过程复杂,成为空间数据匹配的重点。面状居民地匹配骨架线傅里叶变化方法首先把大比例尺面状居民地转化为能够反映其主要轮廓特征的骨架线;其次,把骨架线转化为更易于表达其形态特征的几何形态数据,并对其进行插值计算;第三,对几何形态数据采用傅里叶变换,获取匹配双方骨架线之间的相关系数;最后,通过相关系数来判断双方骨架线之间是否满足匹配条件,从而得到骨架线所对应居民地的匹配结果。通过等级化处理,把2维面状居民地转化为1维骨架线,有效降低了空间数据的复杂性,并可把许多线要素匹配的方法引入进来;把骨架线转化为几何形态数据,并采用傅里叶变换进行形态计算,线要素的几何形态相似性分析得到显著增强,提高了数据匹配的准确率。通过试验验证及对比分析,证明了本方法的有效性和科学性。  相似文献   

气候系统模式发展中的耦合器研制问题   总被引：18，自引：3，他引：15  

周天军  俞永强  宇如聪  刘海龙  李薇  张学洪 《大气科学》2004,28(6):993-1008

基于"耦合器"框架、采用模块化结构是当今气候系统模式发展的主要技术方向.作者概述了耦合器的基本功能,对目前世界上应用比较广泛的11个耦合器进行了综合评述,重点是美国通用气候模式耦合器和法国的OASIS耦合器,扼要概括了目前较具影响力的三个耦合器发展计划,在此基础上,对耦合器的主要发展态势进行了总结,并结合自身模式发展的需求进行了讨论.  相似文献   

Effect of chlorophyll-a spatial distribution on upper ocean temperature in the central and eastern equatorial Pacific   总被引：1，自引：0，他引：1  

林鹏飞  刘海龙  张学洪 《大气科学进展》2008,25(4):585-596

Effect of the spatial distributions of chlorophyll-a concentration on upper ocean temperature and currents in the equatorial Pacific is investigated through a set of numerical experiments by using an ocean general circulation model. This study indicates that enhanced meridional gradient of chlorophyll-a between the equator and off-equatorial regions can strengthen zonal circulation and lead to a decrease in equatorial sea surface temperature （SST）. However, the circulation changes by themselves are not effective enough to affect SST in the equatorial cold tongue （CT） region. The comparison between the experiments indicates that the CT SST are more sensitive to chlorophyll-a distribution away from the equator. The off-equatorial chlorophyll-a traps more solar radiation in the mixed layer, therefore, the temperature in the thermoeline decreases. The cold water can then be transported to the equator by the meridional circulation within the mixed layer. Furthermore, the relation among CT SST, the surface heat flux, and the equatorial upwelling are discussed. The study implies the simulation biases of temperature on the equator are not only related to the local ocean dynamics but also related to some deficiency in simulating off-equatorial processes.  相似文献   

耦合模式中潮汐对北大西洋模拟的影响研究     

于溢  刘海龙  林鹏飞  兰健 《气候与环境研究》2018,23(3):259-267

将8个主要平衡分潮加入到耦合模式中,对比研究潮汐对北大西洋模拟影响。由于潮汐的引入,模式模拟SST在北大西洋中纬度区域偏差显著减小,高纬度区域SST降温明显。SST模拟的改变使潮汐试验的海表净热通量模拟误差下降了约30%,但高纬度海冰显著增加。模式中引入潮汐对北大西洋上层环流,尤其是西边界流的路径模拟改进显著,这是SST及海表净热通量模拟改变的主要原因。同时,北大西洋上层和深层西边界流在潮汐的作用下,都表现出环流减弱的特点,这也使得大西洋经向翻转环流在26.5°N处上层2 km的输送减弱,与观测数据更为接近。较弱的大西洋经向翻转环流导致海洋热量在中低纬度聚集而无法输送到高纬度区域,这是造成潮汐试验模拟的海温在中低纬度偏高、高纬度偏低的原因,较弱的热输送也同时导致了潮汐试验中北半球海冰面积增加。  相似文献