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1.
基于耦合器框架，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大气环流谱模式 （SAMIL）最近成功地实现了与海洋、海冰等气候分量模式的耦合，形成了“非通量调整”的海－陆－气－冰直接耦合的气候模式系统（FGOALS-s）。在耦合系统中，由于海温、海冰等的分布由预报模式驱动，大气与海洋、海冰之间引入了相互作用过程，这样大气环流的模拟特征与耦合前会有不同。为分析耦合系统的性能，作者对耦合前后的模拟结果进行了分析比较，重点是大气模拟特征的差异。结果表明，耦合前、后大气环流的基本特征相似，都能成功地模拟出主要的环流系统分布及季节变化，但是由于海温和海冰的模拟存在系统性的偏差，使得耦合后的大气环流受到明显影响。例如耦合后热带海温偏冷，南大洋、北太平洋和北大西洋等中纬度地区的海温偏高，导致海温等值线向高纬海域的伸展较弱，海温经向梯度减小。耦合后海冰在北极区域范围偏大，在南极周边地区则偏小。海温、海冰分布模拟的偏差影响到中、高纬低层大气的温度。热带海温偏低，使得赤道地区降水偏弱，凝结潜热减少，热带对流层中高层温度比耦合前要低，大气温度的经向梯度减小。经向温度梯度的改变，直接影响到对平均经圈环流及西风急流强度的模拟。尽管耦合系统中海温、海冰的模拟存在偏差，但在亚洲季风区，耦合后季风环流及降水等的分布都比耦合前单独大气模式的结果合理，表明通过海[CD*2]气相互作用可减少耦合前季风区的模拟误差，改善季风模拟效果。比较发现，海温、海冰模拟的偏差，除与海洋模式中经向热输送偏弱、海冰模式中海冰处理等有关外，也与大气模式中总云量模拟偏低有关。大气模式本身的误差，特别是云、辐射过程带来的误差，对耦合结果具有极为重要的影响。完全耦合后，这些误差通过与海洋、海冰的反馈作用而放大。因此，对于FGOALS-s而言，要提高耦合系统的整体性能，除改进各气候分量模式的模拟性能外，需要重点改进大气模式中的云、辐射过程。 相似文献
2.
10个CMIP5模式对亚澳季风环流及其变率的模拟 总被引：1，自引：0，他引：1
利用参加第五次耦合模式比较计划(Coupled Model Intercomparison Project Phase 5,简称CMIP5)的10个海气耦合模式的输出结果,比较了这些模式对6种季风指数年际变化的模拟能力,并从季风区大气环流场的气候态以及海表温度异常(SSTA)与季风的相关关系两个方面对季风指数的模拟差异原因进行了讨论。得到结论:CMIP5模式对于季风指数年际变化模拟的结果与观测资料差异较大,其中对南亚季风指数(Webster- Yang index)模拟最好,模式集合会显著改进对南亚季风指数的模拟效果;不同模式基本可以描述出各个季风区大气环流场的气候态分布特征;耦合模式对南亚季风指数模拟的关键可能在于对SSTA的年际变化以及SSTA与季风相关关系的准确模拟。 相似文献
3.
气候系统模式FGOALS-s1.1对热带降水年循环模态的模拟 总被引：5，自引：0，他引：5
文中评估了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)新一代耦合气候模式Fgoals_s1.1对热带降水年循环模态的模拟能力。通过与观测表层海温(SST)强迫的大气模式SAMIL试验结果比较,分析了海气耦合过程对年循环模态模拟效果的影响。结果表明Fgoals_s1.1能合理再现热带地区降水年循环模态的基本特征。Fgoals_s1.1模拟出了年平均降水场中的主要降水中心,但模拟的赤道和南太平洋降水偏多,而北太平洋降水则偏少。Fgoals_s1.1的季风模态降水呈现与观测一致的关于赤道反对称的特征,其模拟偏差大部分来自大气分量,尤其是在赤道外。Fgoals_s1.1的主要缺陷在于它对春秋非对称模态模拟能力低于单独大气模式,这主要是由于耦合模式模拟的SST距平的年循环位相与观测相反。SST纬向梯度的位相偏差使得太平洋沃克环流和印度洋的反沃克环流在春季强于秋季,最终导致模拟的春秋非对称模态的偏差。Fgoals_s1.1模拟的季风区范围接近观测,存在的问题在于模拟的西北太平洋季风区、东亚季风区都偏小。本文结果表明,大气模式偏差仅是Fgoals_s1.1在降水年循环模态模拟上的偏差的部分来源,改进模式模拟的SST,特别是赤道地区SST季节循环,是今后Fgoals_s1.1发展过程中急需解决的问题。 相似文献
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区域气候模式REMO对东亚季风季节变化的模拟研究 总被引：8，自引：2，他引：6
将欧洲区域气候模式REMO首次应用于东亚区域,利用该模式对1980年和1990年东亚季风季节变化进行了模拟研究,并将模拟结果与NCEP再分析资料进行比较,以检验该模式对东亚季风的模拟能力.研究表明,区域气候模式REMO能够较好地模拟出东亚地区高、低空的大气环流特征,模拟的高度场、流场和温度场与NCEP再分析资料场都比较一致.模拟结果显示了东亚季风的月变化和季节转换特征.模拟的降水场与GPCC降水资料的对比结果表明,REMO能较为成功地模拟出东亚地区降水的空间分布,并能较好地反映降水的季节变化及主要降水趋势,夏季降水模拟偏大,整个区域平均的降水量偏差约为18%左右. 相似文献
5.
青藏高原隆升影响夏季大气环流的敏感性试验 总被引：9，自引：1，他引：9
本文用球带范围的大气环流耦合模式，模拟了青藏高原隆升过程中大气环流的变化。模拟的结果表明，高原对大气的加热作用随着高原地形的升高而加强，而其中潜热加热的贡献占据第一位。高原隆升加剧了高原上空大气的上升运动，使高低空的高低压系统得到了加强，增强了南亚和东亚的季风强度，并且引起高原地区降水明显增加，地表面平均温度剧烈下降。尽管如此，青藏高原的隆升并没有从根本上改变大气环流形势，海陆分布才是形成当代大气环流及季风的根本因子。因此，要模拟地质历史时期气候状况，除了高原地形外，还须考虑更多的因子，尤其是海陆分布的变化。 相似文献
6.
区域海气耦合模式模拟的2003年东亚夏季风季节内振荡 总被引：1，自引：0，他引：1
评估了一个区域海气耦合模式(由区域环境系统集成模式RIEMS和普林斯顿海洋模式POM组成)对2003年东亚夏季风季节内振荡(ISO)的模拟性能。通过与观测海温驱动单独大气模式结果的比较,分析了海气耦合过程对东亚夏季大气ISO模拟性能的影响。结果表明:耦合模式能够模拟出2003年中国东部地区夏季降水的气候态分布,模拟的中国东部尤其是江淮地区大气ISO活动较单独大气模式更为显著。同时,耦合模式能够较好地再现大气ISO经向上北传的传播特征,模拟的江淮流域降水处于活跃和中断期时西北太平洋地区低频降水和环流异常在强度和空间分布上较单独大气模式都更为合理。相比于单独大气模式,耦合模式对大气ISO模拟的改善,一方面与其对气候态西北太平洋副热带高压和相关对流层底层风场模拟的改善有关,另一方面与其包含海气相互作用,因而对低频降水与海温和水汽辐合位相关系模拟的改善有关。 相似文献
7.
本文基于观测和再分析资料，采用水汽收支诊断和合成分析方法，对新一代气候系统模式FGOALS-g3模拟的全球季风进行了系统评估，给出其较之前版本FGOALS-g2的优缺点，并通过与其大气分量模式GAMIL结果的比较，讨论了海气耦合过程的影响。结果表明，FGOALS-g3能合理再现全球季风气候态的基本特征，包括年平均、年循环模态、季风降水强度和季风区范围等，但模式低估陆地季风区年平均降水，高估海洋平均降水，模拟的热带地区春秋非对称模态偏强。研究指出FGOALS-g3模拟的陆地季风区范围偏小，这与模式模拟的夏季水汽垂直平流（尤其是热力项）偏小有关。年际变率上，FGOALS-g3能再现El Ni?o年全球季风降水偏少的整体特征，其不足之处在于部分季风区的降水异常存在一定偏差，例如其模拟的El Ni?o年西非季风区降水偏多和西南印度洋的偶极子型降水异常，均与观测分布不一致，且模式中西北太平洋季风区降水较观测偏多。这是由于El Ni?o年，模式中西非高层无弱辐合中心，且海洋性大陆较观测偏暖，对流中心西移。相较于FGOALS-g2,FGOALS-g3对环流、季风降水的年际变率和季风–ENSO关系的模... 相似文献
8.
BCC_CSM模式对热带降水年循环模态的模拟 总被引：7，自引：2，他引：5
本文评估了国家气候中心发展的两个不同分辨率海—陆—气—冰多圈层耦合气候系统模式BCC_CSM1.1和BCC_CSM1.1 (m) 对热带降水两个年循环模态——揭示降水冬夏季节差异的季风模态和揭示过渡季节春季和秋季非对称特征的春秋非对称模态的模拟能力,讨论了模拟偏差产生的可能原因。分析结果表明,BCC_CSM1.1和BCC_CSM1.1 (m) 均能合理再现全球年平均降水的基本分布特征,也能较合理再现热带降水年循环模态的基本分布特征,尤其季风模态中降水与环流关于赤道反对称的特征;能够较合理再现春秋非对称模态与热带海洋表面温度(SST)年循环之间的关系。大气温度场、环流场以及热带SST的模拟偏差对降水季风模态有影响;热带SST年循环的偏差对降水春秋非对称模态的模拟偏差有贡献;模式分辨率对降水年循环模态的模拟也有一定影响。对比分析显示,大气模式和陆面模式水平分辨率提高之后模式在某些模拟性能上有所提高,这表现在:BCC_CSM1.1 (m) 模拟的1～12月降水气候态的空间变率更接近观测;热带海表温度年循环总体上更接近观测;模拟的热带降水年循环模态的部分特征更合理。但BCC_CSM1.1 (m) 的模拟结果相对观测仍存在较大偏差,有待进一步改进。 相似文献
9.
东亚夏季风的模拟研究──3个区域气候模式的对比 总被引：16，自引：0，他引：16
全球环流模式在东亚地区模拟可靠性评估研究表明存在不确定性，尤以降水更明显．该模式更难于模拟小范围（如一个省）和小时间尺度（如日）的气候变化．本研究用３个区域气候模式作１９９１年东亚夏季（５～８月）季风洪涝气候的模拟．其模拟结果与观测场作了严格的对比并进行了３个模式的相互对比．研究表明，３个区域气候模式成功地模拟了１９９１年夏季发生在我国江淮流域及日本南部的洪涝和几次特大暴雨过程以及相应的大气环流形势的分布． 相似文献
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11.
The numerical simulation experiment of climate at Last Glacial Maximum (LGM.21 ka BP)in China is made by using an atmospheric general circulation model (AGCM) coupled with landsurface processes (AGCM SSiB) and earth orbital parameters and boundary forcing conditions at21 ka.The modeled climate features are compared with reconstructed conditions at 21 ka frompaleo-lake data and pollen data.The results show that the simulated climate conditions at 21 ka inChina are fairly comparable with paleo-climatological data.The climate features at 21 ka in Chinafrom the experiment are characterized by a drier in the east and a wetter in the west and in theTibetan Plateau as well.According to the analysis of distribution of pressure and precipitation,aswell as the intensity of atmospheric circulation at 21 ka,monsoon circulation in eastern Asia wassignificantly weak comparing with the present.In the Tibetan Plateau,the intensity of summermonsoon circulation was strengthened,and winter monsoon was a little stronger than the present.The simulation with given forcing boundary conditions,especially the different vegetationcoverage,can reproduce the climate condition at the LGM in China,and therefore providesdynamical mechanisms on the climate changes at 21 ka. 相似文献
12.
The numerical simulation experiment of climate at Last Glacial Maximum (LGM.21 ka BP) in China is made by using an atmospheric general circulation model (AGCM) coupled with land surface processes (AGCM+SSiB) and earth orbital parameters and boundary forcing conditions at21 ka.The modeled climate features are compared with reconstructed conditions at 21 ka from paleo-lake data and pollen data.The results show that the simulated climate conditions at 21 ka in China are fairly comparable with paleo-climatological data.The climate features at 21 ka in China from the experiment are characterized by a drier in the east and a wetter in the west and in the Tibetan Plateau as well.According to the analysis of distribution of pressure and precipitation,as well as the intensity of atmospheric circulation at 21 ka,monsoon circulation in eastern Asia was significantly weak comparing with the present.In the Tibetan Plateau,the intensity of summer monsoon circulation was strengthened,and winter monsoon was a little stronger than the present.The simulation with given forcing boundary conditions,especially the different vegetation coverage,can reproduce the climate condition at the LGM in China,and therefore provides dynamical mechanisms on the climate changes at 21 ka. 相似文献
13.
The effect of bias on control simulation is a significant issue for climate change modeling studies. We investigated the effect of the sea surface temperature (SST) bias in present day (0 ka) Atmosphere–Ocean Coupled General Circulation Model (AOGCM) simulations on simulations of the mid-Holocene (6 ka, i.e., 6,000 years before present) Asian monsoon enhancement. Because changes in ocean heat transport have a negligible effect on the 6 ka Asian monsoon (Ohgaito and Abe-Ouchi in Clim Dyn 29(1):39–50, 2007), we used an Atmospheric General Circulation Model (AGCM) rather than an AOGCM. Simulations using the AGCM coupled to a mixed layer ocean model (MLM) were conducted for 0 and for 6 ka with different ocean heat transport estimated from the climatological SST of the 0 ka simulations from nine Paleoclimate Modeling Intercomparison Project (PMIP) phase 2 (PMIP2) AOGCMs (henceforth “MA” is used to refer to experiments using the AGCM coupled with the MLM). No correlation between MA and the corresponding PMIP2 was seen in the 0 ka precipitation and it was not very strong for the 6 ka precipitation enhancement. Thus, the influences from the different AGCMs play a substantial role on the 0 ka precipitation and the 6 ka precipitation enhancement. The sensitivity experiments indicated that it was the pattern of the 0 ka SST bias which played a dominant role in the 0 ka precipitation and the 6 ka precipitation enhancement, not the difference in the mean value of the SST bias. The distributions of the 6 ka precipitation enhancements for the nine PMIP2 AOGCMs and nine MA experiments were compared. These showed that the effects of SST bias on 6 ka precipitation enhancement among the AOGCMs were not negligible. The effects of biases among the AGCMs were not negligible either, but of comparable size. That is, improvements in both the SST bias and the AGCM contribute to simulate better 6 ka monsoon. 相似文献
14.
This study provides a detailed analysis of the mid-Holocene to present-day precipitation change in the Asian monsoon region. We compare for the first time results of high resolution climate model simulations with a standardised set of mid-Holocene moisture reconstructions. Changes in the simulated summer monsoon characteristics (onset, withdrawal, length and associated rainfall) and the mechanisms causing the Holocene precipitation changes are investigated. According to the model, most parts of the Indian subcontinent received more precipitation (up to 5 mm/day) at mid-Holocene than at present-day. This is related to a stronger Indian summer monsoon accompanied by an intensified vertically integrated moisture flux convergence. The East Asian monsoon region exhibits local inhomogeneities in the simulated annual precipitation signal. The sign of this signal depends on the balance of decreased pre-monsoon and increased monsoon precipitation at mid-Holocene compared to present-day. Hence, rainfall changes in the East Asian monsoon domain are not solely associated with modifications in the summer monsoon circulation but also depend on changes in the mid-latitudinal westerly wind system that dominates the circulation during the pre-monsoon season. The proxy-based climate reconstructions confirm the regional dissimilarities in the annual precipitation signal and agree well with the model results. Our results highlight the importance of including the pre-monsoon season in climate studies of the Asian monsoon system and point out the complex response of this system to the Holocene insolation forcing. The comparison with a coarse climate model simulation reveals that this complex response can only be resolved in high resolution simulations. 相似文献
15.
A possible role of solar radiation and ocean in the mid-Holocene East Asian monsoon climate 总被引：8，自引：5，他引：3
An atmospheric general circulation model (AGCM) and an oceanic general circulation model (OGCM) are asynchronously coupled to simulate the climate of the mid-Holocene period. The role of the solar radiation and ocean in the mid-Holocene East Asian monsoon climate is analyzed and some mechanisms are revealed. At the forcing of changed solar radiation induced by the changed orbital parameters and the changed SST simulated by the OGCM, compared with when there is orbital forcing alone, there is more precipitation and the monsoon is stronger in the summer of East Asia, and the winter temperature increases over China. These agree better with the reconstructed data. It is revealed that the change of solar radiation can displace northward the ITCZ and the East Asia subtropical jet, which bring more precipitation over the south of Tibet and North and Northeast China. By analyzing the summer meridional latent heat transport, it is found that the influence of solar radiation change is mainly to increase the convergence of atmosphere toward the land, and the influence of SST change is mainly to transport more moisture to the sea surface atmosphere. Their synergistic effect on East Asian precipitation is much stronger than the sum of their respective effects. 相似文献
16.
A Possible Impact of Cooling over the Tibetan Plateau on the Mid-Holocene East Asian Monsoon Climate 总被引：5，自引：3，他引：5
By using a 9-level global atmospheric general circulation model developed at the Institute of Atmospheric Physics (IAP9L-AGCM) under the Chinese Academy of Sciences, the authors investigated the response of the East Asian monsoon climate to changes both in orbital forcing and the snow and glaciers over the Tibetan Plateau at the mid-Holocene, about 6000 calendar years before the present (6 kyr BP). With the Earth’s orbital parameters appropriate for the mid-Holocene, the IAP9L-AGCM computed warmer and wetter conditions in boreal summer than for the present day. Under the precondition of continental snow and glacier cover existing over part of the Tibetan Plateau at the mid-Holocene, the authors examined the regional climate response to the Tibetan Plateau cooling. The simulations indicated that climate changes in South Asia and parts of central Asia as well as in East Asia are sensitive to the Tibetan Plateau cooling at the mid-Holocene, showing a significant decrease in precipitation in northern India, northern China and southern Mongolia and an increase in Southeast Asia during boreal summer. The latter seems to correspond to the weakening, southeastward shift of the Asian summer monsoon system resulting from reduced heat contrast between the Eurasian continent and the Pacific and Indian Oceans when a cooling over the Tibetan Plateau was imposed. The simulation results suggest that the snow and glacier environment over the Tibetan Plateau is an important factor for mid-Holocene climate change in the areas highly influenced by the Asian monsoon. 相似文献
17.
Simulation of paleoclimate over East Asia at 6 ka BP and 21 ka BP by a regional climate model 总被引：5，自引：0，他引：5
Using a regional climate model with detailed land surface processes (RegCM2), East Asian monsoon climates at 6 ka BP and 21 ka BP are simulated by prescribing vegetation and employing paleovegetation respectively in order to examine land surface effects on East Asian climate system and the potential mechanisms for climate change. The RegCM2 with a 120 × 120 km2 resolution has simulated the enlargement of the seasonal cycle of insolation, the temperature rising the whole year, and the reduction of perpetual snow in high latitudes at 6 ka BP. The simulation shows the East Asian summer monsoon strengthening, precipitation and P–E increasing, and the monsoon rain belt shifting westwards and northwards. Effect of paleovegetation included in the modeling reduced surface albedo and caused an increase in the winter temperature, which led to weakening of the winter continental cold anticyclone over China. The results make the seasonal characteristics of simulated temperature changes in better agreement with the geological records, and are an improvement over previous simulations of Paleoclimate Modeling Intercomparison Project (PMIP). The RegCM2 simulated the 21 ka BP climate with lowered temperature throughout the year, and with precipitation reduced in most areas of East Asia (but increased in both the Tibetan Plateau and Central Asia). Low temperature over East Asia led to the strengthening of the East Asian winter monsoon and the shrinking of the summer monsoon. The effect of paleovegetation included in the experiment has enlarged the glacial climate influence in East Asia, which is closer to geological data than the PMIP simulations directly driven by insolation, glaciation and low CO2 concentration. 相似文献
18.
The Seasonal Climate and Low Frequency Oscillation in the Simulated Mid-Holocene Megathermal Climate 总被引：7，自引：2，他引：5
Wang Huijun 《大气科学进展》2000,17(3):445-457
l.IntroductionThegoalofPMIP(PaleoclimateModellingIntercomparisonProject)istocomparethestate-ofthe-artclimatemodels'simulationsforthepastclimateonthebasisofthepaleoclimatedata.Oneofthemostinterestingperiodsisthemid-Holoceneduring8.5-3.OkaBPwiththemaximumin7.2-6.OkaBP(beforepresent)inChina(Shietal.,l992).Itwasre-vealedthatthetemPeraturewasl-4'Chigherandtheprecipitationwas4O%-loO%largercomparedtothepresentoverChina(Shietal.,l992;Anetal..l99l;Kongetal.,l99O,l99l).Therehavebeensomesimula… 相似文献
19.
Studies of climate change 6,000 years before present using atmospheric general circulation models (AGCMs) suggest the enhancement
and northward shift of the summer Asian and African monsoons in the Northern Hemisphere. Although enhancement of the African
monsoonal precipitation by ocean coupling is a common and robust feature, contradictions exist between analyses of the role
of the ocean in the strength of the Asian monsoon. We investigated the role of the ocean in the Asian monsoon and sought to
clarify which oceanic mechanisms played an important role using three ocean coupling schemes: MIROC, an atmosphere–ocean coupled
general circulation model [C]; an AGCM extracted from MIROC coupled with a mixed-layer ocean model [M]; and the same AGCM,
but with prescribed sea surface temperatures [A]. The effect of “ocean dynamics” is quantified through differences between
experiments [C] and [M]. The effect of “ocean thermodynamics” is quantified through differences between experiments [M] and
[A]. The precipitation change for the African and Asian monsoon area suggested that the ocean thermodynamics played an important
role. In particular, the enhancement of the Asian monsoonal precipitation was most vigorous in the AGCM simulations, but mitigated
in early summer in ocean coupled cases, which were not significantly different from each other. The ocean feedbacks were not
significant for the precipitation change in late summer. On the other hand, in Africa, ocean thermodynamics contributed to
the further enhancement of the precipitation from spring to autumn, and the ocean dynamics had a modest impact in enhancing
precipitation in late summer. 相似文献
20.
LIU Yu HE Jinhai LI Weiliang CHEN Longxun LI Wei ZHANG Bo 《Acta Meteorologica Sinica》2010,24(4):468-483
Using a regional climate model MM5 nested with an atmospheric global climate model CCM3, a series of simulations and sensitivity experiments have been performed to investigate responses of the mid-Holocene climate to different factors over China. Model simulations of the mid-Holocene climate change, especially the precipitation change, are in good agreement with the geologic records. Model results show that relative to the present day (PD) climate, the temperature over China increased in the mid-Holocene, and the increase in summer is more than that in winter. The summer monsoon strengthened over the eastern China north of 30°N, and the winter monsoon weakened over the whole eastern China; the precipitation increased over the west part of China, North China, and Northeast China, and decreased over the south part of China.The sensitive experiments indicate that changes in the global climate (large-scale circulation background),vegetation, earth orbital parameter, and CO2 concentration led to the mid-Holocene climate change relative
to the PD climate, and changes in precipitation, temperature and wind fields were mainly affected by change of the large-scale circulation background, especially with its effect on precipitation exceeding 50%. Changes in vegetation resulted in increasing of temperature in both winter and summer over China, especially over eastern China; furthermore, its effect on precipitation in North China accounts for 25% of the total change.Change in the orbital parameter produced the larger seasonal variation of solar radiation in the mid-Holocene than the PD, which resulted in declining of temperature in winter and increasing in summer; and also had
an important effect on precipitation with an effect equivalent to vegetation in Northeast China and North China. During the mid-Holocene, CO2 content was only 280×10-6, which reduced temperature in a very small magnitude. Therefore, factors affecting the mid-Holocene climate change over China from strong to weak are large-scale circulation pattern, vegetation, earth orbital parameter, and CO2 concentration. 相似文献