共查询到17条相似文献，搜索用时 125 毫秒
1.
A new two-way land-atmosphere interaction model （R42_AVIM） is fulfilled by coupling the spectral atmospheric model （SAMIL_R42L9） developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences （LASG/IAP/CAS） with the land surface model, Atmosphere-Vegetation-Interaction-Model （AVIM）. In this coupled model, physical and biological components of AVIM are both included. Climate base state and land surface physical fluxes simulated by R42_AVIM are analyzed and compared with the results of R42_SSIB [which is coupled by SAMIL_R42L9 and Simplified Simple Biosphere （SSIB） models]. The results show the performance of the new model is closer to the observations. It can basically guarantee that the land surface energy budget is balanced, and can simulate June-July-August （JJA） and December-January- February （DJF） land surface air temperature, sensible heat flux, latent heat flux, precipitation, sea level pressure and other variables reasonably well. Compared with R42_SSIB, there are obvious improvements in the JJA simulations of surface air temperature and surface fluxes. Thus, this land-atmosphere coupled model will offer a good experiment platform for land-atmosphere interaction research. 相似文献
2.
A fast version of LASG/IAP climate system model and its 1000-year control integration 总被引：2，自引：1，他引：1
A fast version of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geo- physical Fluid Dynamics(LASG)/Institute of Atmospheric Physics(IAP)climate system model is briefly documented.The fast coupled model employs a low resolution version of the atmospheric component Grid Atmospheric Model of IAP/LASG(GAMIL),with the other parts of the model,namely an oceanic component LASG/IAP Climate Ocean Model(LICOM),land component Common Land Model(CLM),and sea ice component from National Center for Atmospheric Research Community Climate System Model (NCAR CCSM2),as the same as in the standard version of LASG/IAP Flexible Global Ocean Atmosphere Land System model(FGOALS g).The parameterizations of physical and dynamical processes of the at- mospheric component in the fast version are identical to the standard version,although some parameter values are different.However,by virtue of reduced horizontal resolution and increased time-step of the most time-consuming atmospheric component,it runs faster by a factor of 3 and can serve as a useful tool for long- term and large-ensemble integrations.A 1000-year control simulation of the present-day climate has been completed without flux adjustments.The final 600 years of this simulation has virtually no trends in global mean sea surface temperatures and is recommended for internal variability studies.Several aspects of the control simulation’s mean climate and variability are evaluated against the observational or reanalysis data. The strengths and weaknesses of the control simulation are evaluated.The mean atmospheric circulation is well simulated,except in high latitudes.The Asian-Australian monsoonal meridional cell shows realistic features,however,an artificial rainfall center is located to the eastern periphery of the Tibetan Plateau persists throughout the year.The mean bias of SST resembles that of the standard version,appearing as a"double ITCZ"(Inter-Tropical Convergence Zone)associated with a westward extension of the equatorial eastern Pacific cold tongue.The sea ice extent is acceptable but has a higher concentration.The strength of Atlantic meridional overturning is 27.5 Sv.Evidence from the 600-year simulation suggests a modulation of internal variability on ENSO frequency,since both regular and irregular oscillations of ENSO are found during the different time periods of the long-term simulation. 相似文献
3.
Performance of a Reconfigured Atmospheric General Circulation Model at Low Resolution 总被引：3，自引：2，他引：3
Paleoclimate simulations usually require model runs over a very long time.The fast integration version of a state-of-the-art general circulation model (GCM),which shares the same physical and dynamical processes but with reduced horizontal resolution and increased time step,is usually developed.In this study,we configure a fast version of an atmospheric GCM (AGCM),the Grid Atmospheric Model of IAP/LASG (Institute of Atmospheric Physics/State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics),at low resolution (GAMIL-L,hereafter),and compare the simulation results with the NCEP/NCAR reanalysis and other data to examine its performance.GAMIL-L,which is derived from the original GAMIL,is a finite difference AGCM with 72×40 grids in longitude and latitude and 26 vertical levels.To validate the simulated climatology and variability,two runs were achieved.One was a 60-year control run with fixed climatological monthly sea surface temperature (SST) forcing,and the other was a 50-yr (1950-2000) integration with observational time-varying monthly SST forcing.Comparisons between these two cases and the reanalysis,including intra-seasonal and inter-annual variability are also presented.In addition,the differences between GAMIL-L and the original version of GAMIL are also investigated. The results show that GAMIL-L can capture most of the large-scale dynamical features of the atmosphere, especially in the tropics and mid latitudes,although a few deficiencies exist,such as the underestimated Hadley cell and thereby the weak strength of the Asia summer monsoon.However,the simulated mean states over high latitudes,especially over the polar regions,are not acceptable.Apart from dynamics,the thermodynamic features mainly depend upon the physical parameterization schemes.Since the physical package of GAMIL-L is exactly the same as the original high-resolution version of GAMIL,in which the NCAR Community Atmosphere Model (CAM2) physical package was used,there are only small differences between them in the precipitation and temperature fields.Because our goal is to develop a fast-running AGCM and employ it in the coupled climate system model of IAP/LASG for paleoclimate studies such as ENSO and Australia-Asia monsoon,particular attention has been paid to the model performances in the tropics.More model validations,such as those ran for the Southern Oscillation and South Asia monsoon, indicate that GAMIL-L is reasonably competent and valuable in this regard. 相似文献
4.
In Part I, the authors succeeded in coupling the spectral atmospheric model （SAMIL_R42L9） developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences （LASG/IAP/CAS） with the land surface model, Atmosphere-Vegetation-Interaction-Model （AVIM） and analyzed the climate basic state and land surface physical fluxes simulated by R42_AVIM. In this Part Ⅱ, we further evaluate the simulated results of the biological processes, including leaf area index （LAI）, biomass and net primary productivity （NPP） etc. Results indicate that R42_AVIM can simulate the global distribution of LAI and has good consistency with the monthly mean LAI provided by Max Planck Institute for Meteorology. The simulated biomass corresponds reasonably to the vegetation classifications. In addition, the simulated annual mean NPP has a consistent distribution with the data provided by IGBP and MODIS, and compares well with the work in literature. This land-atmosphere coupled model will offer a new experiment tool for the research on the two-way interaction between climate and biosphere, and the global terrestrial ecosystem carbon cycle. 相似文献
5.
The seasonal variations of the Asian monsoon were explored by applying the atmospheric general circulation model R42L9 that was developed recently at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP/CAS). The 20-yr (1979-1998) simulation was done using the prescribed 20-yr monthly SST and sea-ice data as required by Atmospheric Model Intercomparison Project (AMIP)Ⅱ in the model. The monthly precipitation and monsoon circulations were analyzed and compared with the observations to validate the model‘s performance in simulating the climatological mean and seasonal variations of the Asian monsoon. The results show that the model can capture the main features of the spatial distribution and the temporal evolution of precipitation in the Indian and East Asian monsoon areas. The model also reproduced the basic patterns of monsoon circulation. However, some biases exis tin this model. The simulation of the heating over the Tibetan Plateau in summer was too strong. The overestimated heating caused a stronger East Asian monsoon and a weaker Indian monsoon than the observations. In the circulation fields, the South Asia high was stronger and located over the Tibetan Plateau. The western Pacific subtropical high was extended westward, which is in accordance with the observational results when the heating over the Tibetan Plateau is stronger. Consequently, the simulated rainfall around this area and in northwest China was heavier than in observations, but in the Indian monsoon area and west Pacific the rainfall was somewhat deficient. 相似文献
6.
It is well known that significant interdecadal variation of the East Asian summer monsoon （EASM） occurred around the end of the 1970s. Whether these variations can be attributed to the evolution of global sea surface temperature （SST） and sea ice concentration distribution is investigated with an atmospheric general circulation model （AGCM）. The model is forced with observed monthly global SST and sea ice evolution through 1958-1999. A total of four integrations starting from different initial conditions are carried out. It is found that only one of these reproduces the observed interdecadal changes of the EASM after the 1970s, including weakened low-level meridional wind, decreased surface air temperature and increased sea level pressure in central China, as well as the southwestward shift of the western Pacific subtropical high ridge and the strengthened 200-hPa westerlies. This discrepancy among these simulated results suggests that the interdecadal variation of the EASM cannot be accounted for by historical global SST and sea ice evolution. Thus, the possibility that the interdecadal timescale change of monsoon is a natural variability of the coupled climate system evolution cannot be excluded. 相似文献
7.
Impacts of a GCM＇s Resolution on MJO Simulation 总被引：3，自引：0，他引：3
Long-term integrations are conducted using the Spectral Atmospheric Model （referred to as SAMIL）, which was developed in the Laboratory for Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG） in the Institute of Atmospheric Physics （IAP）, with different resolutions to inves-tigate sensitivity of the Madden-Julian Oscillation （MJO） simulations to the model＇s resolution （horizontal and vertical）. Three resolutions of the model, R15L9, R42L9 and R42L26, with identical physical processes, all produced the basic observed features of the MJO, including the spatiotemporal space-time spectra and eastward propagation. No fundamental differences among these simulations were found. This indicates that the model resolution is not a determining factor for simulating the MJO. Detailed differences among these modeling results suggest, however, that model resolution can substantially affect the simulated MJO in certain aspects. For instance, at a lower horizontal resolution, high frequency disturbances were weaker and the structures of the simulated MJO were better defined to a certain extent. A higher vertical resolution led to a more realistic spatiotemporal spectrum and spatial distribution of MJO precipitation. Meanwhile, increasing the model＇s resolution improved simulation of the climatology. However, increasing the resolution should be based on improving the cumulus parameterization scheme. 相似文献
8.
A new hybrid coupled model(HCM) is presented in this study, which consists of an intermediate tropical Pacific Ocean model and a global atmospheric general circulation model. The ocean component is the intermediate ocean model(IOM)of the intermediate coupled model(ICM) used at the Institute of Oceanology, Chinese Academy of Sciences(IOCAS). The atmospheric component is ECHAM5, the fifth version of the Max Planck Institute for Meteorology atmospheric general circulation model. The HCM integrates its atmospheric and oceanic components by using an anomaly coupling strategy. A100-year simulation has been made with the HCM and its simulation skills are evaluated, including the interannual variability of SST over the tropical Pacific and the ENSO-related responses of the global atmosphere. The model shows irregular occurrence of ENSO events with a spectral range between two and five years. The amplitude and lifetime of ENSO events and the annual phase-locking of SST anomalies are also reproduced realistically. Despite the slightly stronger variance of SST anomalies over the central Pacific than observed in the HCM, the patterns of atmospheric anomalies related to ENSO,such as sea level pressure, temperature and precipitation, are in broad agreement with observations. Therefore, this model can not only simulate the ENSO variability, but also reproduce the global atmospheric variability associated with ENSO, thereby providing a useful modeling tool for ENSO studies. Further model applications of ENSO modulations by ocean–atmosphere processes, and of ENSO-related climate prediction, are also discussed. 相似文献
9.
用 IAP／LASG GOALS模式模拟CO2增加引起的东亚地区气候变化 总被引：19，自引：0，他引：19
Two simulations, one for the control run and another for the perturbation run, with a global coupled ocean-atmosphere-land system model (IAP / LASG GOALS version 4) have been carried out to study the global warming, with much detailed emphasis on East Asia. Results indicate that there is no climate drift in the control run and at the time of CO2 doubling the global temperature increases about 1.65℃. The GOALS model is able to simulate the observed spatial distribution and annual cycles of temperature and precipitation for East Asia quite well. But, in general, the model underestimates temperature and overestimates rainfall amount for regional annual average. For the climate change in East Asia, the temperature and precipitation in East Asia increase 2. l℃ and 5% respectively, and the maximum warming occurs at middle-latitude continent and the maximum precipitation increase occurs around 25°N with reduced precipitation in the tropical western Pacific. 相似文献
10.
By using monthly NCEP/NCAR meridional gridpoint wind data at the levels of 1000, 850, 700,600, 500, 400, 300, 200, 150 and 100 hPa from 1948 to 2004, the intensity of global cross-equatorial flows is calculated. The spatial and temporal variation of global cross-equatorial flows at the 850-hPa level are shown and discussed. The results show that the strength of the 850-hPa global cross-equatorial flows represent obvious long-term variation and interdecadal change during the period. Evidence suggests that the cross-equatorial flow of the passages at 45 - 50 °E in June to August, 105 - 115 °E in May to September,130 - 140 °E in May to September and May to November and 20 - 25 °E in February to April intensified and that the cross-equatorial flow of the passages at 50 - 35 °W in June to August weaken in the past 57 years, with an increase of 0.25m/s/10a for summer Somali Jet and increase of 0.32 m/s/10a for crossequatorial flow at 130 - 140 °E in May to September The results of Singular Spectrum Analysis (SSA) for the time series indicate that for the cross-equatorial flow at 850 hPa, the interdecadal and long-term trend changes are 35% - 45%, and the interannual variation is no more than 30%, in variance contribution. The results also reveal that the interannual variation of intensity of the summer cross-equatorial flows in the Pacific is significantly correlated with Southern Oscillation. With weak Southern Oscillation, strong crossequatorial flows in Pacific will happen, though the summer Somali Jet is only a little positively correlated with North Atlantic Oscillation (NAD). 相似文献
11.
An atmosphere-vegetation interaction model (AVIM) has been coupled with a nine-layer General Circulation Model (GCM) of Institute of Atmospheic Physics / State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (IAP/LASG), which is rhomboidally truncated at zonal wave number 15, to simulate global climatic mean states. AVIM is a model having inter-feedback between land surface processes and eco-physiological processes on land. As the first step to couple land with atmosphere completely, the physiological processes are fixed and only the physical part (generally named the SVAT (soil-vegetation-atmosphere-transfer scheme) model) of AVIM is nested into IAP/LASG L9R15 GCM. The ocean part of GCM is prescribed and its monthly sea surface temperature (SST) is the climatic mean value. With respect to the low resolution of GCM, i.e., each grid cell having longitude 7.5° and latitude 4.5°, the vegetation is given a high resolution of 1.5° by 1.5° to nest and couple the fine grid cells of land with the coarse grid cells of atmosphere. The coupling model has been integrated for 15years and its last ten-year mean of outputs was chosen for analysis.Compared with observed data and NCEP reanalysis, the coupled model simulates the main characteristics of global atmospheric circulation and the fields of temperature and moisture. In particular, the simulated precipitation and surface air temperature have sound results. The work creates a solid base on coupling climate models with the biosphere. 相似文献
12.
将一个大气植被相互作用模式(AVIM)与大气所LASG的R15九层大气环流模式GOALS相耦合．用来模拟多年平均的全球气候状况。AVIM是一个陆地表面陆面和生理过程相互反馈的模型。作为陆气耦合的第一步,暂不考虑AVIM中的生理过程,而首光将其物理过程[相当于通常的SVAT(土壤—植被—大气—传输方案)模型]与大气所LASG的九层大气环流模式耦合起来．其中海洋模式部分不参与积分,海面温度是多年平均的气候伯。考虑到GCM的分辨率较低(7．5°×4．5°)而植被分布必须有较高的分辨率(1.5°×1.5°),采取广大气与地表面粗细网格的嵌套耦合。模式积分15年,取最后10年的平均值作分析。将模拟的气候要素场与观测值和NCEP再分析资料作了比较,气候模拟结果反映了全球环流与温湿场的主要特征,特别是降水和地面气温的模拟效果较好。这为今后气候模式与生物圈的耦合奠定广一个良好的基础。 相似文献
13.
SAMIL模式中Tiedtke 积云对流方案对热带降水模拟的影响 总被引：2，自引：1，他引：1
目前, 大多数全球耦合模式及大气环流模式在降水模拟中普遍存在不同程度的“热带偏差”问题, 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所发展的全球大气环流谱模式SAMIL-R42L26也存在这一现象, 主要表现在SPCZ (南太平洋辐合区) 降水过强且过分东伸、 赤道附近降水偏少等方面。本文通过修改SAMIL中的积云对流方案有效地削弱了这一偏差, 并进一步探讨其原因, 发现对流方案修改后, 改变了对流层低层至地面的温度分布状态, 进而影响了风速及散度场的模拟, 最终通过垂直速度的调整反作用于对流过程。比较修改前后对流过程云底质量通量, 发现修改后的方案主要通过削弱浅对流来提高热带降水的模拟性能。 相似文献
14.
Cloud is one of the uncertainty factors influencing the performance of a general circulation model (GCM)．Recently,the State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics(LASG／IAP)has developed a new version of a GCM(R42L9)．In this 相似文献
15.
大气环流模式和耦合模式模拟的降水-海温关系之比较 总被引：9，自引：6，他引：3
本文讨论了气候系统耦合模式FGOALS_s模拟的局地降水和海温的关系, 并通过与单独大气模式SAMIL的AMIP试验结果进行对比分析, 考察了海气耦合过程对局地降水和海温关系模拟的影响。结果表明, 耦合模式FGOALS_s和单独大气模式SAMIL在模拟局地降水和海温关系上各有优势。在赤道中东太平洋地区, 观测中局地降水和海温的关系是海洋强迫为主, FGOALS_s模拟的海洋对大气的强迫比观测偏弱, 因此, SAMIL相对于FGOALS_s更有优势。在西北太平洋东部地区, 观测中夏秋季节降水和海温的关系是大气强迫为主, 由于考虑了海气相互作用过程, FGOALS_s对降水和海温关系的模拟能力要优于单独的大气模式。此外, 由于大气模式SAMIL的云参数化方案导致的模拟偏差, 在赤道中东太平洋地区 (9～11月), 降水增加时入射的短波辐射通量也是增加的, 并且这种模拟的偏差在耦合后仍然保留了下来, 导致了与观测不符的云[CD*2]辐射反馈过程。因此, 改进大气模式的云参数化方案是未来工作重点之一。此外, 分析发现耦合模式模拟的潜热通量的变化过分依赖海气湿度差。 相似文献
16.
SAMIL大气环流模式海面湍流通量参数化方案研究 总被引：1，自引：1，他引：0
将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大气环流谱模式SAMIL_R42L26 2.08中的海气通量参数化方案——Louis方案, 与新发展的一种新型近海层湍流通量参数化方案——LGLC方案进行比较和分析。离线测试结果表明, LGLC方案计算的通量结果与观测数据具有更好的一致性, 且由于其区分热力粗糙度和动力粗糙度, 使得对热量通量的计算更加准确。在线测试则证明, 引入LGLC方案的SAMIL模式对洋面风应力、 感热通量、 潜热通量和降水率的模拟能力有了进一步的提高, 尤其对北半球夏季印度季风和南海季风区的降水改善明显。 相似文献
17.
耦合模式FGOALS_s模拟的东亚夏季风 总被引：9，自引：6，他引：3
本文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的海气耦合模式FGOALS_s对东亚夏季风的模拟能力, 并通过与观测海温强迫下单独大气模式SAMIL试验结果的比较, 分析了海气耦合过程对模式性能的影响。结果表明, FGOALS_s基本能够模拟出东亚夏季风系统的气候态分布及其演变过程, 但也存在明显偏差, 主要表现为模拟的温度场在对流层中上层一致性偏冷, 导致模式中环流系统强度偏弱; 而温度经向梯度模拟的不足, 直接影响到东亚副热带西风急流的模拟。通过与观测海温强迫下SAMIL模拟结果的对比发现, SAMIL模拟的温度场、 环流场以及风场较之耦合模式结果更接近观测, 但也存在与FGOALS_s类似的模式偏差。因此, 大气模式固有的偏差对耦合模式的模拟偏差有重要影响。分析发现, 对于西太平洋降水的模拟而言, 耦合模式结果更加合理, 表明海气相互作用过程对模式性能有重要影响。本文的结果表明, 大气模式自身的误差是导致耦合模式误差的主要原因。通过更新云－辐射模块改进大气模式模拟的温度场, 应是FGOALS_s后续发展的首要工作。 相似文献