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1.
An eddy-permitting oceanic general circulation model and its preliminary evaluation 总被引：56，自引：11，他引：45
1. Introduction The current oceanic general circulation models(GCMs) used in climate studies, especially those serv-ing as component models in coupled GCMs, havean average resolution around 2? (IPCC, 2001). Theoceanic GCMs with relatively coarse resolutions canreproduce the major observed features of the large-scale circulations, but there are some insurmount-able di?culties. It was documented by Gates (1992)that the main defects of the coarse resolution oceanicGCMs include the repres… 相似文献
2.
任意正交曲线坐标系下的海洋模式动力框架的发展与评估 总被引：1，自引：1，他引：0
本文发展了一个可以适用于任意水平正交曲线坐标系的海洋模式动力框架,并将其应用于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系统海洋模式LICOM2.0（LASG/IAP Climate system Ocean Model,version2.0）。在经纬网格坐标系下,新的动力框架与LICOM2.0原有的动力框架模拟结果完全一致。基于新的动力框架,海洋模式可采用能够准确描述北冰洋地形的三极网格,克服了LICOM2.0经纬网格版本必须将北极点处理为孤岛的缺陷,从而显著改进了模式对于北冰洋环流和北大西洋经圈翻转流函数（AMOC）的模拟能力。此外,引进三极网格还可以避免模式网格距随纬度增加而急剧减小带来的计算不稳定,在LICOM2.0的三极网格版本中,模式不需要采用任何空间滤波方案仍然能够保证计算的稳定性,从而与LICOM2.0的经纬网格版本相比,极大地提高了模式的并行效率,这一点在当水平分辨率提高到0.1度时表现得尤为明显,海洋模式的并行加速比可以从经纬网格版本的5.8左右提高到三极网格版本的15.0左右。 相似文献
3.
The effects of changing horizontal resolution are studied using ensembles of seasonal simulations made by a relatively recent
version of the ECMWF model. The model is integrated at T63, TL159 and TL319 spectral resolutions. The last corresponds approximately to a 0.56° latitude-longitude grid and may be considered, by
climate modelling standards, as very high resolution. Though, on average, no dramatically large differences in ensemble mean
quantities are found between the three resolutions, some monotonic (systematic) differences with increasing resolution are
evident. Whilst the better representation of orography with increasing resolution accounts for many differences between the
resolutions considered, not all variations can be associated with changes in local orographic features. The existence of systematic
changes with resolution indicates that the development of numerical models, especially physical parametrizations, should be
carried out simultaneously at various resolutions. The study indicates that the highest model resolution does not always give
the best results in terms of verification. In addition, reanalysis parameters that are mainly driven by model physics may
not be optimal for the verification in such resolution studies.
Received: 11 August 2000 / Accepted: 13 February 2001 相似文献
4.
Fundamental Framework and Experiments of the Third Generation of IAP/LASG World Ocean General Circulation Model 总被引：51，自引：0，他引：51
1.IntroductionThefirstbaroclinicoceanicgeneralcirculationmodel(OGCM)developedattheStateKeyLaboratoryofNumericalModelingforAtmosphericSciencesandGeophysicalFluidDynamics(LASG),InstituteofAtmosphericPhysics(IAP)isafour--layermodelwithitshorizontalresol... 相似文献
5.
使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（LASG/IAP）开发的第三代气候海洋模式（LASG/IAP Climate system Ocean Model version 3, LICOM3.0）低分辨率版本在海洋模式比较计划（Ocean Model Intercomparison Project, OMIP）试验中的模拟数据,描述了南极绕极流（Antarctic Circumpolar Current, ACC）和南大洋经向翻转环流（Meridional Overturning Circulation, MOC）在1958～2009年的平均状态及其变化,并与已有的模式模拟结果和观测结果对比以评估LICOM模式的模拟效果。通过对比已有模式模拟数据发现,LICOM3.0模式模拟的ACC和南大洋MOC在两组OMIP试验中平均状态相仿、结果在合理范围内,但OMIP1试验中海表强迫的变化趋势较OMIP2试验中的变化更大,得到的环流输送在OMIP1试验中增长趋势也更大。 相似文献
6.
The Baseline Evaluation of LASG/IAP Climate System Ocean Model (LICOM) Version 2 总被引：6，自引：0，他引：6 
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下载免费PDF全文 The baseline performance of the latest version (version 2) of an intermediate resolution, stand-alone climate oceanic general circulation model, called LASG/IAP (State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics) Climate system Ocean Model (LICOM), has been evaluated against the observation by using the main metrics from Griffies et al. in 2009. In general, the errors of LICOM2 in the water properties and in the circulation are comparable with the models of Coordinated Ocean-ice Reference Experiments (COREs). Some common biases are still evident in the present version, such as the cold bias in the eastern Pacific cold tongue, the warm biases off the east coast of the basins, the weak poleward heat transport in the Atlantic, and the relatively large biases in the Arctic Ocean. A unique systematic bias occurs in LICOM2 over the Southern Ocean, compared with CORE models. It seems that this bias may be related to the sea ice process around the Antarctic continent. 相似文献
7.
Fundamental framework and experiments of the third generation of IAP / LASG world ocean general circulation model 总被引：36，自引：8，他引：28
A new generation of the IAP / LASG world ocean general circulation model is designed and presented based on the previous 20-layer model, with enhanced spatial resolutions and improved parameterizations. The model uses a triangular-truncated spectral horizontal grid system with its zonal wave number of 63 (T63) to match its atmospheric counterpart of a T63 spectral atmosphere general circulation model in a planned coupled ocean-atmosphere system. There are 30 layers in vertical direction, of which 20 layers are located above 1000 m for better depicting the permanent thermocline. As previous ocean models developed in IAP / LASG, a free surface (rather than “rigid-lid” approximation) is included in this model. Compared with the 20-layer model, some more detailed physical parameterizations are considered, including the along / cross isopycnal mixing scheme adapted from the Gent-MacWilliams scheme. The model is spun up from a motionless state. Initial conditions for temperature and salinity are taken from the three-dimensional distributions of Levitus’ annual mean observation. A preliminary analysis of the first 1000-year integration of a control experiment shows some encouraging improvements compared with the twenty-layer model, particularly in the simulations of permanent thermocline, thermohaline circu?lation, meridional heat transport, etc. resulted mainly from using the isopycnal mixing scheme. However, the use of isopycnal mixing scheme does not significantly improve the simulated equatorial thermocline. A series of numerical experiments show that the most important contribution to the improvement of equatori?al thermocline and the associated equatorial under current comes from reducing horizontal viscosity in the equatorial regions. It is found that reducing the horizontal viscosity in the equatorial Atlantic Ocean may slightly weaken the overturning rate of North Atlantic Deep Water. 相似文献
8.
本文以自嵌套方式，将一个有限区域暴雨数值模式编制成单向和双向的套网格模式，同时又将这两个套网格模式分别与Ｔ４２Ｌ９模式进行了单向嵌套。形成了单向，双向两个双重套网格模式。运用这两个模式对１９９１年７月江淮流域的一次特大暴雨过程进行了数值试验。 相似文献
9.
Pengfei LIN Zhipeng YU Hailong LIU Yongqiang YU Yiwen LI Jirong JIANG Wei XUE Kangjun CHEN Qian YANG Bowen ZHAO Jilin WEI Mengrong DING Zhikuo SUN Yaqi WANG Yao MENG Weipeng ZHENG Jinfeng MA 《大气科学进展》2020,37(3):239-249
The datasets of two Ocean Model Intercomparison Project(OMIP)simulation experiments from the LASG/IAP Climate Ocean Model,version 3(LICOM3),forced by two different sets of atmospheric surface data,are described in this paper.The experiment forced by CORE-II(Co-ordinated Ocean–Ice Reference Experiments,Phase II)data(1948–2009)is called OMIP1,and that forced by JRA55-do(surface dataset for driving ocean–sea-ice models based on Japanese 55-year atmospheric reanalysis)data(1958–2018)is called OMIP2.First,the improvement of LICOM from CMIP5 to CMIP6 and the configurations of the two experiments are described.Second,the basic performances of the two experiments are validated using the climatological-mean and interannual time scales from observation.We find that the mean states,interannual variabilities,and long-term linear trends can be reproduced well by the two experiments.The differences between the two datasets are also discussed.Finally,the usage of these data is described.These datasets are helpful toward understanding the origin system bias of the fully coupled model. 相似文献
10.
本文用CORE-IAF（Coordinated Ocean-ice Reference Experiments–Interannual Forcing）外强迫场分别强迫LICOM3（LASG/IAP Climate System Ocean Model Version 3）和POP2（Parallel Ocean Program version 2）两个海洋模式，并分析了这两个模式中太平洋北赤道逆流（NECC）的模拟结果。我们发现LICOM3和POP2模拟的NECC强度均弱于实测，这和Sun et al.（2019）的研究结果一致，也进一步证明了海洋模式中NECC偏弱是CORE-IAF外强迫场造成的，海表风应力及对应的风应力旋度是海洋模式准确模拟NECC的最主要因子。同时，我们也分析了NECC的模拟在动力机制上的差别，这里的动力强迫项包括风应力项、平流项和余项。我们发现模式的外强迫场虽然相同，但是两个模式中各动力强迫项（风应力项、平流项和余项）对NECC模拟的影响并不完全相同。 相似文献
11.
不同分辨率CCSM4对东亚和中国气候模拟能力分析 总被引：9，自引：4，他引：5
本文利用通用气候系统模式CCSM4在三种水平分辨率下的工业化革命前期气候模拟试验,结合观测和再分析资料,比较了各分辨率下模式对中国温度和降水、东亚海平面气压和850 hPa风场的模拟能力,综合评价了模式分辨率对东亚和中国气候模拟的影响.结果表明,三种分辨率对中国温度均具有很好的模拟能力,除春季外,低分辨率(T31,约3.75°×3.75°)对全年温度的模拟能力均要稍好于中(f19,约1.9°×2.5°)、高(f09,约0.9°×1.25°)分辨率;各分辨率对中国降水的模拟能力远不如温度,除冬季外全年都出现的中部地区虚假降水并未因为模式分辨率提高而得到本质改善;对于东亚海平面气压场,低分辨率在冬季模拟能力相对最好,中等分辨率在夏季相对较好,而高分辨率的模拟能力均表现最差;低分辨率对850 hPa东亚冬季风和夏季风的模拟能力均要好于中、高分辨率,而两种较高分辨率的模拟能力则比较接近.总的来说,低分辨率CCSM4在东亚和中国气候模拟中表现出了较大优势,加之其计算代价小,适合进行需要较长时间积分的气候模拟研究. 相似文献
12.
大气边界层湍流运动是地球大气运动最重要的能量输送过程之一。当数值模式分辨率接近活跃含能湍涡长度尺度时，湍流运动被部分解析，被称为“灰色区域”，传统的边界层方案不适合此时模式湍流问题的描述。为了提高模式边界层方案在包括“灰色区域”的不同网格尺度上的描述能力，适应不同分辨率模式的需要，在雷诺平均湍流理论基础上，修正Mellor-Yamada-Nakanishi-Niino (MYNN)方案湍流长度尺度参数和非局地湍流的参数表达，改进湿度和温度在“灰色区域”的湍流输送参数化及对网格尺度的自适应能力。利用改进的MYNN尺度自适应方案，分别采用3 km和1 km、1.5 km和0.5 km分辨率单向嵌套网格WRF中尺度模式，对2014年2月26日的一次黄海海雾过程进行模拟试验，检验不同分辨率下改进后的MYNN大气边界层参数化方案的合理性和对海雾的模拟效果。尺度自适应MYNN大气边界层参数化方案在千米级网格尺度上获得稳定、合理的湍流垂直输送计算结果。参照雾区卫星云图，不同分辨率模式低层云水混合比模拟结果具有稳定表现，模拟的雾区分布和温度、湿度等物理量结构都较好地再现了再分析“观测事实”，初步表明该参数化方案有较高的网格尺度自适应能力。 相似文献
13.
一个灵活的海洋——大气耦合环流模式 总被引：33，自引：13，他引：20
Based on the National Center for Atmospheric Research (NCAR) Climate System Model version 1(CSM-1), a Flexible coupled General Circulation Model version 0 (FGCM-0) is developed in this study through replacing CSM-1＇s oceanic component model with IAP L30T63 global oceanic general circulation model and some necessary modifications of the other component models. After the coupled model FGCM--0 is spun up for dozens of years, it has been run for 60 years without flux correction. The model does not only show the reasonable long-term mean climatology, but also reproduce a lot of features of the interannual variability of climate, e.g. the ENSO-like events in the tropical Pacific Ocean and the dipole mode pattern in the tropical Indian Ocean. Comparing FGCM-0 with the NCAR CSM-1, some common features are found, e.g. the overestimation of sea ice in the North Pacific and the simulated double ITCZ etc.The further analyses suggest that they may be attributed to errors in the atmospheric model. 相似文献
14.
Impact of horizontal resolution on the simulation of the Asian summer monsoon and tropical cyclones in the JMA global model 总被引：1，自引：0，他引：1
To investigate the impact of increasing horizontal resolution on a simulated model climate, we conducted an experiment using the Japan Meteorological Agency (JMA) operational global atmosphere model (JMA-GSM0103). The models with four different horizontal resolutions ranging from T42 to T213 have been integrated over three years with prescribed climate sea surface temperature in the experiment. The distributions of 3-year averaged seasonal mean fields are basically similar among the models with different resolution, although there are some monotonic and systematic differences with increasing resolution. However, the climatology of synoptic scale phenomena is well represented in higher resolution models. The position and amount of precipitation in Baiu front (or Mei-yu) at higher resolution models agree well with observations. The start time of northward propagation of heavy precipitation over the Bay of Bengal, which is associated with Indian monsoon development, is also well simulated in higher resolution models. The number of tropical cyclones increases monotonically with resolutions. The simulated tropical cyclones become more realistic with increasing resolution. 相似文献
15.
将时间滑动相关方法 STC(sliding temporal correlation)用于研究混沌系统和海洋环流模式的可信计算时间RCT(reliable computation time),Lorenz混沌系统的数值试验表明用STC求得的可预报时间和可信计算时间,与使用传统误差限方法所得结果一致,证明了其有效性。对海洋环流模式LICOM和NEMO的研究发现:1.当海洋模式以非耦合的方式运行时,试验的结果表明其海表温度SST的可信计算时间较长,平均达到6个月以上,这主要是由于海洋模式的运行过程中,采用恢复性边界条件使模拟结果不会太过偏离观测值。对于强迫场从1月开始的试验,LICOM模式的SST可信计算时间在赤道东太平洋和西北太平洋地区存在RCT低值区,其数值不超过2个月。而NEMO模式在赤道太平洋地区全是RCT高值区,NEMO模式的RCT低值区域出现在赤道外的太平洋和大西洋中纬度地区,强迫场从7月开始的试验,RCT纬向平均分布与1月有相反的形式。2.海洋模式以耦合方式运行时,由于去掉了恢复边界条件作用,海洋模式预报的SST可信计算时间明显减小,年平均RCT为1个月左右。按季节平均得到的RCT变化不大,在30~40天之间,RCT的大值区春季位于南半球,而秋季位于北半球,可达2个月以上。耦合模式中所模拟的500 h Pa高度场的RCT与单独运行的大气模式所得结果相差不大,仍在2周以内。3.无论是按季节平均还是按海区平均所得到的RCT分布,都在30~60天左右,只有极少数区域在特定季节可以达到80天以上,这说明在海气耦合模式中,由于计算不确定造成的可预报上限一般不超过2~3个月,这比使用资料分析得到可预报期限短很多,因此根据木桶原理,RCT可能是制约海气耦合模式SST预报能力的一个重要因素。 相似文献
16.
复杂地形区域风场模拟的准确率一直是风能研究领域的难点和重点。WRF模式是目前风能评估领域应用最广泛的天气数值模式之一,但该模式在复杂地形区域存在对平原、山谷风速高估且对山顶风速低估的系统性误差,并有研究建立次网格地形方案以订正误差。而次网格地形方案在不同水平分辨率下常出现错误的修正结果,该文基于高精度地形高程数据分析了方案失效的主要原因,发现其方程组中判断山体形态特征的阈值-20在过低和过高水平分辨率下均失去参考性。针对这一原因,将方案中影响关键参数Ct的地形高度算子与模式水平分辨率进行拟合,形成地形高度算子与水平分辨率相依赖的线性关系,获得不同分辨率下更适合的山体形态阈值。通过与自动气象站10 m风速对比分析了修正前后WRF对低层风速的模拟效果,结果显示:修正后的次网格地形方案能够分别在较低和较高分辨率下,部分矫正原方案错误的订正结果,使低层风速模拟更接近实况。修正后的次网格地形方案可为复杂地形区域开展高分辨率风场模拟提供参考。 相似文献
17.
基于半拉格朗日 (semi-Lagrangian) 方案的数值天气预报模式, 求解半拉格朗日轨迹上游点变量, 通常采用传统直线逐点拉格朗日多项式插值, 由已知模式格点 (欧拉网格点) 的数值插值获得。对于三维空间上游点的插值, N阶精度需要O(N3) 运算量。N增大, 运算量将大幅增加, 特别耗费计算机机时, 而采用Cascade插值法 (降阶插值法) 则只需要O(N) 运算量。它的显著特点是:用曲线代替直线, 通过一系列中间过渡网格点, 在曲线上用一维拉格朗日插值, 使得相邻拉格朗日格点或中间过渡点的插值不再是孤立的, 而且可以重复使用某些中间结果, 达到减少运算量的目的。将这种方法合理应用于GRAPES模式, 并根据模式的特点, 对Cascade插值过程中独立变量的距离分段计算, 从而有利于实现并行计算。计算结果表明Cascade插值法与传统直线逐点插值法相比, 计算效率平均提高约30%, 同时不降低精度。 相似文献
18.
边界层参数化方案在“灰色区域”尺度下的适用性评估 总被引：2，自引：0，他引：2
随着数值预报模式分辨率的提高,当模式网格距与含能湍涡的长度尺度相当时,模式动力过程可解析一部分湍流运动,而剩余的湍流运动仍需参数化,此时便产生了湍流参数化的“灰色区域”问题。对传统的PBL（Planetary Boundary Layer）方案在“灰色区域”下的适用性评估,是改进PBL方案以使其能够适应分辨率变化的前提和基础。本研究基于干对流边界层的大涡模拟试验,比较了WRF（Weather Research and Forecast Model）模式中四种常用的边界层参数化方案[YSU（Yonsei University）、MYJ（Mellor-Yamada-Janjic）、MYNN2.5（Mellor-Yamada-Nakanishi-Niino Level 2.5）、MYNN3）]在“灰色区域”尺度下的表现。研究表明,混合层内总热通量对所使用的参数化方案和水平分辨率均不敏感。不同参数化方案中次网格与网格通量的比例表现出对水平网格距不同的依赖性。局地PBL方案（MYJ、MYNN2.5）在混合层内的平均位温随网格距减小而增大,次网格通量随网格距减小而减小,较参考湍流场对次网格通量有所低估。YSU方案的非局地项几乎不随水平格距改变而变化,对次网格通量的表征并未表现出较强的分辨率依赖性,且过强的非局地次网格输送使混合层内温度层结呈弱稳定,抑制了可分辨湍流输送,不易于激发次级环流。MYNN3方案的非局地次网格通量（负梯度输送项）随网格距减小而减小,使其对次网格通量的表征具有较好的分辨率依赖性。PBL方案在“灰色区域”尺度下的适用性与具体分辨率有关。以分辨率500 m为例,四种PBL方案中不存在一种最佳方案,能对边界层的热力结构和湍流统计特征均有准确的描述。 相似文献
19.
Comprehensive global energetics analysis is carried out for the NCAR CCM2 with different horizontal resolutions of R15, T42,
T63, and T106 to assess the effect of various model truncations on the global energetics characteristics in climate models.
Both the energy levels and energy transformations are examined over the zonal wave number domain during a northern winter
and summer. In addition to the simulated atmosphere, the ECMWF global analysis during 1986 to 1990 is analyzed for comparison
using the same diagnostic scheme. Previous studies have revealed that zonal kinetic energy is supplied by synoptic disturbances
in terms of the zonal-wave interactions of kinetic energy. According to our result, however, such an energy flow from eddies
to zonal motions is valid only for zonal wave numbers up to about 30. We find that the zonal-wave interactions of kinetic
energy change sign beyond wave number 30 where the energy is transformed from zonal to eddies for both the ECMWF and CCM2-T106.
The large-scale zonal motions are diffusive against the short waves beyond wave number 30, which may well be parameterized
by various forms of the diffusion schemes. We suggest from this result that the atmospheric disturbances with wave numbers
lower than 30 are necessary to represent accurately the two-way interactions between zonal and eddy motions, because these
waves can actively influence the behavior of the zonal motions. Based on this finding, we suggest that the model resolution
of R15 is inadequate for climate studies from the energetics point of view, and that resolution of T42 is the minimum requirement
to represent the general circulation adequately. Some other discrepancies are discussed in detail for the coarse resolution
climate models.
Received: 15 July 1996/Accepted: 3 January 1997 相似文献
20.
尺度适应(scale-aware)的物理过程是现代数值预报发展的一种趋势,本文针对GRAPES_Meso(Global/Regional Assimilation and Prediction Enhanced System)模式没有考虑物理过程尺度适应的现状,首先在KFeta(Kain-Fritsch Eta)积云对流参数化方案中引进了尺度适应过程,对该方案的对流时间尺度、格点垂直速度以及夹卷率进行了基于尺度适应参数化的改进。为研究尺度适应KFeta方案与原KFeta方案对不同分辨率模式模拟结果的影响,选取了一次华南飑线过程进行数值模拟和影响分析。结果表明:在3 km、5 km、10 km、20 km水平分辨率的GRAPES_Meso模式中,尺度适应KFeta方案相比原方案,对降水强度及落区分布的模拟有一定的正效果,随着模式水平分辨率提高,次网格降水减少、格点降水增多、对流层中低层夹卷略有增强,对原来存在的对流层高层及低层偏冷的偏差有一定的改进,对流活跃区域的上升气流强度、云中水凝物含量更符合真实的天气系统演变。综合来看,改进后的方案更适用于高分辨率数值预报模式,该研究结果可以为尺度适应对流参数化方案的应用及数值模式强降水预报性能的优化提供有益的参考。 相似文献