海气耦合环流模式的研制及其敏感性

文章介绍了近年来海气耦合模式的进展以及这些模式在气候敏感性试验中的应用。     

中国地区云光学厚度和云滴有效半径变化趋势

利用ISCCP最新的D2云气候资料集和MODIS云的资料,给出中国地区云的光学厚度和云滴有效半径的分布特征;分别对季节平均和年平均时间序列进行线性趋势分析,并进行了显著性检验。结果表明：夏季云的光学厚度和有效半径的变化趋势最显著。结合云量变化情况,可发现云滴有效半径的变化对云光学厚度的影响可能在夏季最大,也就是说,气溶胶的间接气候效应可能在夏季最强;云量、云光学厚度和云滴有效半径的变化也表明长江以南地区和青藏高原地区可能是气溶胶间接气候效应比较显著的地区。中国地区冰云光学厚度与有效直径的相关具有很强的区域特征,说明冰云的微物理机制比水云更复杂。     

海气耦合非线性随机模式求解探讨

本文首先对一个假定随机强迫为高斯白噪声的四次方非线性海气耦合随机模式进行了ε一阶近似的摄动处理，将非线性随机模式化为显含随机项的线性系统和隐含随机项的非线性系统，通过对输出响应的分析表明:该模式结构和随机项的特性使得随机强迫输出的响应只能通过模式的线性区；非线性项仅对气候系统的方差及其对应的频谱有一定量的偏差作用，而对一般输出特性没有贡献。在这基础上，求出了模式输出谱，并给出了计算。     

海气耦合环流模式及耦合技术的研究

介绍了近年来国内外海气耦合环流模式的研究、发展趋势,对不同模式的耦合技术及其人预报试验进行了综合分析,从ＥＮＳＯ预测与耦合环流模式的组成分类、模式的气候漂移及其处理技术（耦合方案）的特点,模式的季节、年际、年代际预报能力等方面评述了当前海气耦合环流模式的研究进展和影响耦合模式预报能力的有关问题,指出目前发展海气耦合模式的观难点所在,并就我国现状提出了进行针对性研究的具体想法。     

简单海气耦合模式大气运动方程的非线性对ENSO循环模拟的影响

研究简单海气耦合模式大气运动方程非线性对ENSO循环的影响,即讨论大气运动方程的纬向非线性、经向非线性、纬向和经向非线性对ENSO循环的影响。同时,讨论了ENSO循环对大气运动方程非线性的敏感性问题。数值实验证明,大气运动方程的非线性对ENSO循环的影响明显,并且ENSO循环对大气运动方程的非线性非常敏感。因此,研究简单海气耦合模式中大气运动方程的非线性对ENSO循环的影响,对进一步理解ENSO循环的物理机制,具有一定的理论意义和实用价值。     

一类非线性海气耦合波的研究

建立了一类非线性海气耦合波的模式,并用该模式作了解析研究,讨论了该类海气耦合波的存在条件,发现当海气耦合较强时分别存在以海洋为主导方面及以大气为主导方面的两支海气耦合波,而耦合较弱时则仅有前者存在。还求得了该模式中该类海气耦合波的椭圆余弦波解及孤立波解,并对以海洋为主导的海气耦合波的性质作了讨论,认为海气相互作用耦合也是产生大气季节内振荡的机制之一。     

全球海气耦合模式系统(NIM/COAMS)Ⅰ.一种新的再分析同步耦合方案

利用NCAR CCM2十八层全球大气环流谱模式和IAP／LASG OGCM二十层全球大洋环流模式，设计了一个通量场再分析同步耦合方案FRAC（Flux Re—Analysis Coupling scheme），建立了全球海气耦合模式系统（NIM／COAMS）。利用EOF理论消除分量模式通量在海气非线性相互作用过程中产生的高频振荡，保留模式通量场的主要成分．使模式误差不致被迅速放大。模拟结果表明，积分前10a全球平均海表温度仅上升0．1℃，全球平均表面温度仅上升0．3℃，以后基本保持不变，模式没有出现明显的气候漂移，50a积分显示，模式对气候态的模拟与观测基本一致，部分结果优于未耦合模式。     

GISS海气耦合模式的基本气候态评估

该文简单介绍了GISS海气耦合模式, 并且利用该模式进行数值模拟, 以此来判断其模拟能力, 尤其是对亚洲地区的模拟。结果表明:该模式模拟的亚洲地区大气和海洋的气候状况比较接近实况, 具有一定的气候模拟能力。同时, 由于其较粗的分辨率, 对计算机要求不高, 容易利用目前国内中小型计算机进行长期运转, 是一个简易的数值模拟工具。文章也讨论了该模式模拟的不足之处, 如亚洲地区模拟的地面气温偏低, 海温略偏高, 青藏高原南部夏季降水过大, 中国华北夏季降水偏少等。     

海气耦合气侯模式的依时解

运用量子力学方法,精确地求出了海气耦合随机－动力模式的依时解．对依时解的分析表明：当气候系统处于基态时,系统的行为呈布朗运动形式,由此从理论上证明了Ｈａｓｓｅｌｍａｎｎ关于随机气候模式建立的立足点．当系统处于第一激发态时,系统运动呈随时间衰减的形式;在一定条件下则为周期振荡,主周期长度为２．３年．最后将结果用来讨论二氧化碳浓度倍增时的气候影响．     

Sensitivity of the Grid-point Atmospheric Model of IAP LASG （GAMILI.I.0） Climate Simulations to Cloud Droplet Effective Radius and Liquid Water Path

This paper documents a study to examine the sensitivity to cloud droplet effective radius and liquid water path and the alleviation the energy imbalance at the top of the atmosphere and at the surface in the latest version of the Grid-point Atmospheric Model of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP） （GAMIL1.1.0）. Considerable negative biases in all flux components, and thus an energy imbalance, are found in GAMIL1.1.0. In order to alleviate the energy imbalance, two modifications, namely an increase in cloud droplet effective radius and a decrease in cloud liquid water path, have been made to the cloud properties used in GAMIL. With the increased cloud droplet effective radius, the single scattering albedo of clouds is reduced, and thus the reflection of solar radiation into space by clouds is reduced and the net solar radiation flux at the top of the atmosphere is increased. With the reduced cloud optical depth, the net surface shortwave radiation flux is increased, causing a net warming over the land surface. This results in an increase in both sensible and latent heat fluxes over the land regions, which is largely balanced by the increased terrestrial radiation fluxes. Consequently, the energy balance at the top of atmosphere and at the surface is achieved with energy flux components consistent with available satellite observations.     

海气耦合模式FGOALS_gl模拟的水汽和云辐射反馈过程

本文分析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)发展的快速耦合模式FGOALS_gl对低纬太平洋区域水汽温室效应(Ga)和云辐射强迫特征的模拟能力,讨论了模拟偏差的成因.结果表明,FGOALS_gl能合理再现Ga、云辐射强迫的气候态空间分布特征,但也存在明显的偏差.模式低估了冷...     

Climate Change Projections for the 21st Century by the NCC/IAP T63 Model with SRES Scenarios

1. IntroductionFor the latest 15 years, the climate change hasbeen paid more attention by the policy-makers, scien-tists, and the public. The global warming of 0.4-0.8°Cfor the 20th century has been measured by the instru-mental observations. The atmospheric concentrationof CO2 increased from 280 ppm for the period 1000-1750 to 368 ppm in the year 2000 with an increase of27%-35%. In the light of new evidence and taking intoaccount the remaining uncertainties, most of the ob-served warming o…     

Simulation of ~(14)C in IAP/LASG L30T63 Ocean Model

1. Introduction14C is a radioactive isotope of carbon, whose halftime is about 5730 yr. Under natural circumstance,14C comes into being in the stratosphere because of thenitrogen explosion of cosmic radial. 14C is mixed inthe atmosphere, absorbed by oceans, and then trans-ported into deep ocean. 14C radioactively reduces asits age increases. The reduction process of 14C canuncover the evolvement process of sea water's age andrenewal time.14 C content is usually described with one in athousan…     

The Importance of the Shape Parameter in a Bulk Parameterization Scheme to the Evolution of the Cloud Droplet Spectrum during Condensation

The shape parameter of the Gamma size distribution plays a key role in the evolution of the cloud droplet spectrum in the bulk parameterization schemes. However, due to the inaccurate specification of the shape parameter in the commonly used bulk double-moment schemes, the cloud droplet spectra cannot reasonably be described during the condensation process. Therefore, a newly-developed triple-parameter condensation scheme with the shape parameter diagnosed through the number concentration, cloud...     

LASG/IAP和BCC大气环流模式模拟的云辐射强迫之比较

通过与ISCCP (International Satellite Cloud Climatology Project)逐月辐射资料的比较,本文从气候态和对ENSO响应的角度,评估了国内的三个大气环流模式BCC AGCM、IAP GAMIL和IAP SAMIL对云辐射强迫的模拟能力,讨论了影响模拟结果不确定性的因素.分...     

Impact of the Time Scale of Model Sensitivity Response on Coupled Model Parameter Estimation

That a model has sensitivity responses to parameter uncertainties is a key concept in implementing model parameter estimation using filtering theory and methodology.Depending on the nature of associated physics and characteristic variability of the fluid in a coupled system,the response time scales of a model to parameters can be different,from hourly to decadal.Unlike state estimation,where the update frequency is usually linked with observational frequency,the update frequency for parameter estimation must be associated with the time scale of the model sensitivity response to the parameter being estimated.Here,with a simple coupled model,the impact of model sensitivity response time scales on coupled model parameter estimation is studied.The model includes characteristic synoptic to decadal scales by coupling a long-term varying deep ocean with a slow-varying upper ocean forced by a chaotic atmosphere.Results show that,using the update frequency determined by the model sensitivity response time scale,both the reliability and quality of parameter estimation can be improved significantly,and thus the estimated parameters make the model more consistent with the observation.These simple model results provide a guideline for when real observations are used to optimize the parameters in a coupled general circulation model for improving climate analysis and prediction initialization.     

云凝结核浓度对WRF模式模拟飑线降水的影响：不同云微物理参数化方案的对比研究

采用WRF模式模拟一次影响中国广东省的飑线过程, 分别选取Morrison、 Thompson07、 Thompson09和WDM6云微物理方案实施了四组试验, 每组试验包括不同云凝结核（CCN）浓度的三次模拟, 称为 “低浓度”、 “中浓度” 和 “高浓度”, 将模拟区域划分为深对流、 浅对流和层云区域, 对比分析四组试验中CCN浓度变化对模拟的总降水量、 不同区域降水率和不同区域面积的影响, 进一步分析了云微物理过程、 动力环流强度等受CCN浓度变化的影响。发现: （1） 由于不同云微物理过程与CCN浓度有着直接或间接的联系、 不同云微物理过程之间存在复杂的关联、 云微物理过程与动力环流之间发生非线性耦合, 采用不同的云微物理方案导致模拟的CCN—降雨影响既有相似、 也有差异; （2）模拟的CCN—降水影响在采用Thompson09和Thompson07方案时更显著, 采用WDM6方案时最小; （3）四组模拟试验均出现CCN浓度增加延迟降水产生、 初期降水减弱的情况, 在模拟后期降水量也随着CCN浓度增加而减小, 而飑线成熟阶段CCN—降水影响更加复杂。     

Water Vapor and Cloud Radiative Forcings over the Pacific Ocean Simulated by the LASG/IAP AGCM: Sensitivity to Convection Schemes

Characteristics of the total clear-sky greenhouse effect (GA) and cloud radiative forcings (CRFs), along with the radiative-related water vapor and cloud properties simulated by the Spectral Atmospheric Model developed by LASGIAP (SAMIL) are evaluated. Impacts of the convection scheme on the simulation of CRFs are discussed by using two AMIP (Atmospheric Model Inter-comparison Project) type simulations employing different convection schemes: the new Zhang-McFarlane (NZH) and Tiedtke (TDK) convection schemes. It shows that both the climatological GA and its response to El Nio warming are simulated well, both in terms of spatial pattern and magnitude. The impact of the convection scheme on GA is not significant. The climatological longwave CRF (LWCRF) and its response to El Nio warming are simulated well, but with a prominently weaker magnitude. The simulation of the climatology (response) of LWCRF in the NZH (TDK) run is slightly more realistic than in the TDK (NZH) simulation, indicating significant impacts of the convection scheme. The shortwave CRF (SWCRF) shows large biases in both spatial pattern and magnitude, and the results from the TDK run are better than those from the NZH run. A spuriously excessive negative climatological SWCRF over the southeastern Pacific and an insufficient response of SWCRF to El Nio warming over the tropical Pacific are seen in the NZH run. These two biases are alleviated in the TDK run, since it produces vigorous convection, which is related to the low threshold for convection to take place. Also, impacts of the convection scheme on the cloud profile are discussed.