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1.
为揭示造成火山强迫气候响应模拟不确定性的原因,第六次国际耦合模式比较计划(CMIP6)设立了火山强迫的气候响应模拟比较计划(VolMIP)。该计划由基于历史火山爆发的理想火山扰动试验组成,包括三组主要的试验:第一组关注短期(季节至年际)大气动力响应;第二组关注海气耦合系统的长期(年际至年代际)响应;第三组关注气候系统对火山群的响应。VolMIP旨在通过给定相同的辐射强迫并进行多成员集合模拟,揭示模式对外强迫响应的不确定性,通过设定不同的背景气候态,阐明内部变率和外强迫对气候响应的相对贡献。  相似文献   

2.
通过2种大气环流模式(GCM)的数值模拟,研究了大气对于赤道东太平洋海温(SST)异常外强迫的“记忆”问题。结果表明,大气对外强迫的“记忆”比传统意义的“记忆”要长得多,这是因为外强迫通过影响大气内部动力过程而激发产生了低频振荡(即大气低频遥响应),使得外强迫的影响可持续相当长的时间,大气对外强迫的“记忆”也就变得相当长。  相似文献   

3.
<正>世界气候研究计划(WCRP)提供的耦合模式对比计划第五阶段(CMIP5)的地球系统模式(ESM)较之以前增加了较为复杂的碳循环,即在原有的全球大气耦合海洋环流模式(AOGCMs)中,把大气与陆地和海洋碳循环过程加入,这样较真实地再现碳循环和物理气候系统之间的相互作用~([1])。为了表征它们之间的相互作用以及考虑碳循环响应于未来的气候变化和CO_2的变化,经常考虑碳—浓度参数化和碳—气候反馈参数化,这是两个强的和相反的反馈。碳—浓度参数化是度量陆地和海洋碳库对大  相似文献   

4.
利用全球海洋—大气快速耦合模式(Fast Ocean-Atmosphere Model,FOAM),采用模式中的初值方法,研究了湾流区海温再现过程及其对北半球大气环流和气候的影响。FOAM模式很好地模拟了北大西洋湾流区的海温"再现"过程,模式中海面热通量异常与SST异常表现出不同步的响应特征。海面热通量异常在初冬季节达到最大值,而SST异常滞后,在冬季晚期达到最大值,从而在初冬和晚冬对北半球大气环流造成不同的影响。初冬季节北半球大气环流主要受海洋热通量异常的强迫,在北大西洋和北太平洋上空呈现相当正压的异常低压槽响应,北极地区为异常高压脊,类似北极涛动的负位相,可能造成欧洲南部和北非大陆气温偏高,亚洲大陆气温偏低。而晚冬季节北半球大气环流主要受SST异常的驱动,在北大西洋和北太平洋上空表现为相当正压的异常高压脊响应,北极地区为异常低压槽,类似北极涛动的正位相,可能造成欧洲南部和北非大陆气温偏低,亚洲大陆气温偏高,中国东部降水异常偏多30%左右。北太平洋大气环流的异常由北大西洋湾流区海洋热通量和SST异常强迫下游大气环流所激发,进一步通过Rossby驻波的能量频散东传至北太平洋而造成的。  相似文献   

5.
文中对IPCC第六次评估报告(AR6)第一工作组(WGI)报告的第七章关于地球能量收支、气候反馈和气候敏感度中的重要内容进行了凝练,并简要总结该方面的最新研究成果和结论。评估显示,自工业革命以来,人类活动造成的有效辐射强迫(ERF)为2.72 [1.96~3.48] W/m2,其中,均匀混合温室气体的贡献为3.32 [3.03~3.61] W/m2,气溶胶的贡献为-1.1 [-1.7~-0.4] W/m2。净的气候反馈参数为-1.16 [-1.81~-0.51] W/(m2∙℃),云仍然是气候反馈整体不确定性的最大来源。平衡态气候敏感度(ECS)和瞬态气候响应(TCR)可用于评估全球平均地表气温对强迫的响应,是衡量全球气候响应的有效手段。ECS和TCR的最佳估计分别为3.0 [2.0~5.0]℃和1.8 [1.2~2.4]℃。  相似文献   

6.
气候系统及模式中反馈机制研究 Ⅰ.研究和方法   总被引:1,自引:1,他引:0       下载免费PDF全文
气候系统中存在着各种各样的气候反馈机制,而气候模式对这些反馈机制描述的差异,正是造成不同模式对同一直接辐射强迫(如二氧化碳加倍)的响应不同的主要原因。因此,只有正确描述气候系统中的各种反馈作用,气候模式才可能用来对未来的气候变化进行预测。为此,本文首先介绍了气候系统及模式反馈机制分析研究时所常用的一些概念,如气候敏感性参数、云辐射强迫等,随后概述了气候模式反馈机制比较分析时常用的各种方法,并指出了这些方法各自的优缺点。而详细的有关气候系统及模式中反馈作用及其机制的分析则在文章的第II部分给出。  相似文献   

7.
气候系统中存在着各种各样的气候反馈机制,而气候模式对这些反馈机制描述的差异,正是造成不同模式对同一直接辐射强迫(如二氧化碳加倍)的响应不同的主要原因。因此,只有正确描述气候系统中的各种反馈作用,气候模式才可能用来对未来的气候变化进行预测。为此,本文首先介绍了气候系统及模式反馈机制分析研究时所常用的一些概念,如气候敏感性参数、云辐射强迫等,随后概述了气候模式反馈机制比较分析时常用的各种方法,并指出了这些方法各自的优缺点。而详细的有关气候系统及模式中反馈作用及其机制的分析则在文章的第II部分给出。  相似文献   

8.
南海年际尺度海气相互作用的初探   总被引:13,自引:0,他引:13  
本文分析了南海海洋大气系统短期气候变化中存在年际振荡的若干观测事实,提出了局地尺度南海海洋与低层大气相互作用的一种可能机制。针对南海表层水温距平和低层风场异常的相关,设计了一个类似与McCreary和Ander-son(1984)模型的简化海气耦合模式。大气部分为随下垫面海温变化而变化的异常风应力阶梯函数与季节性风场的联合;海洋部分为非线性β-平面的约化重力模式。考虑南海海洋大气相互作用中存在的海温与低层大气风场变化之间反馈过程,耦合模式在气候积分中表现出一类约3a的周期性年际振荡。说明这个区域SST、低层大气风场年际振荡是南海海盆尺度的海气相互作用的反映,改进了关于南海SST年际振荡是海洋对大气应力甚低频强迫响应的认识  相似文献   

9.
气候模式     
气候模式建立在物理、化学、生物学等基础上,用数学方程式表现地球气候系统各个圈层相互作用和反馈的主要过程以及与外强迫的关联,广泛应用在气候与气候变化研究中,因此气候模式是气候变暖研究的核心技术。气候变暖的预估几乎完全依赖模式的模拟。历届IPCC第一工作组的评估报告,均  相似文献   

10.
硫酸盐气溶胶直接辐射效应在线与离线模拟方法的比较   总被引:3,自引:0,他引:3  
利用区域气候模式RegCM 2与大气化学模式连接的模拟系统 ,比较了硫酸盐气溶胶辐射强迫的在线、离线模拟方法的硫酸盐柱含量、大气顶直接辐射强迫及地表温度响应。发现 :在线与离线模拟方法得到的硫酸盐柱含量、有无反馈大气顶直接辐射强迫和地表温度响应在许多地区有很大差异 ,这种差异在较小区域平均的尺度上更显著 ,在全区域平均尺度上也较为明显 ,是不能被忽略的 ;结果显示从硫酸盐含量到辐射强迫和地表温度响应逐渐加大的差异 ,说明硫酸盐气溶胶的辐射强迫与模拟方法有关 ,显示出较大的不确定性。  相似文献   

11.
全球气候变化对中国森林生态系统的影响   总被引:15,自引:0,他引:15  
王叶  延晓冬 《大气科学》2006,30(5):1009-1018
人类活动所引起的温室效应及由此造成的全球气候变化和对全球生态环境的影响正引起人们越来越多的重视.作为全球陆地生态系统一个重要组分,中国的森林生态系统对未来全球气候变化的响应更是人们关注的重点.作者系统地总结了全球气候变化对中国森林生态系统分布、生态系统生产力、森林树种以及森林土壤的影响,指出了现阶段该领域研究中存在的一些问题,并对今后需要加强的一些核心问题与研究重点作了展望.  相似文献   

12.
Using the method of radiative ‘kernels’ an analysis is made of water vapour, lapse rate and ‘Planck’ (uniform vertical temperature) long wave feedbacks in models participating in the World Climate Research Program (WCRP) Coupled Model Intercomparison Project phase 3 (CMIP3). Feedbacks are calculated at climate change timescales from the A1B scenario, and at three ‘variability’ timescales from the corresponding preindustrial experiments: seasonal, interannual and decadal. Surface temperature responses show different meridional patterns for the different timescales, which are then manifest in the structures of the individual feedbacks. Despite these differences, mean water vapour feedback strength in models is positive for all models and timescales, and of comparable global magnitude across all timescales except for seasonal, where it is much weaker. Taking into consideration the strong positive lapse rate feedback at seasonal timescales, combined water vapour/lapse rate feedback is indeed similar across all timescales. To a good approximation, global water vapour feedback is found to be well represented by the temperature response along with an assumption of unchanged relative humidity under both variability and climate change. A comparison is also made of model feedbacks with reanalysis derived feedbacks for seasonal and interannual timescales. No strong relationships between individual modelled feedbacks at different timescales are evident: i.e., strong feedbacks in models at variability timescales do not in general predict strong climate change feedback, with the possible exception of seasonal timescales. There are caveats on this (and other) findings however, from uncertainties associated with the kernel technique and from, at times, very large uncertainties in estimating variability related feedbacks from temperature regressions.  相似文献   

13.
An overview of radiative climate feedbacks and ocean heat uptake efficiency diagnosed from idealized transient climate change experiments of 14 CMIP5 models is presented. Feedbacks explain about two times more variance in transient climate response across the models than ocean heat uptake efficiency. Cloud feedbacks can clearly be identified as the main source of inter-model spread. Models with strong longwave feedbacks in the tropics feature substantial increases in cloud ice around the tropopause suggestive of changes in cloud-top heights. The lifting of the tropical tropopause goes together with a general weakening of the tropical circulation. Distinctive inter-model differences in cloud shortwave feedbacks occur in the subtropics including the equatorward flanks of the storm-tracks. Related cloud fraction changes are not confined to low clouds but comprise middle level clouds as well. A reduction in relative humidity through the lower and mid troposphere can be identified as being the main associated large-scale feature. Experiments with prescribed sea surface temperatures are analyzed in order to investigate whether the diagnosed feedbacks from the transient climate simulations contain a tropospheric adjustment component that is not conveyed through the surface temperature response. The strengths of the climate feedbacks computed from atmosphere-only experiments with prescribed increases in sea surface temperatures, but fixed CO2 concentrations, are close to the ones derived from the transient experiment. Only the cloud shortwave feedback exhibits discernible differences which, however, can not unequivocally be attributed to tropospheric adjustment to CO2. Although for some models a tropospheric adjustment component is present in the global mean shortwave cloud feedback, an analysis of spatial patterns does not lend support to the view that cloud feedbacks are dominated by their tropospheric adjustment part. Nevertheless, there is positive correlation between the strength of tropospheric adjustment processes and cloud feedbacks across different climate models.  相似文献   

14.
冰冻圈变化及其对中国气候的影响   总被引:10,自引:0,他引:10  
The cryosphere is a prominent factor in and an indicator of global climate change. It serves one of the most direct and sensitive feedbacks in the climate system, and plays an important role in the earth's climate system. Cryospheric research has attracted unprecedented attention in the context of global warming, and is now one of the most active areas in studies of global change, sustainable development, and the climate system. This paper addresses recent and potential future changes in the cryosphere both globally and within China under the background of global warming. Particular attention is paid to progress toward understanding the impacts of the Tibetan Plateau and Eurasian snow cover, Arctic and Antarctic sea ice, and permafrost and glaciers on Chinese climate. The future development of cryospheric research in China is also discussed.  相似文献   

15.
The sensitivity of the climate system to anthropogenic perturbations over the next century will be determined by a combination of feedbacks that amplify or damp the direct radiative effects of increasing concentrations of greenhouse gases. A number of important geophysical climate feedbacks, such as changes in water vapor, clouds, and sea ice albedo, are included in current climate models, but biogeochemical feedbacks such as changes in methane emissions, ocean CO2 uptake, and vegetation albedo are generally neglected. The relative importance of a wide range of feedbacks is assessed here by estimating the gain associated with each individual process. The gain from biogeochemical feedbacks is estimated to be 0.05–0.29 compared to 0.17–0.77 for geophysical climate feedbacks. The potentially most significant biogeochemical feedbacks are probably release of methane hydrates, changes in ocean chemistry, biology, and circulation, and changes in the albedo of the global vegetation. While each of these feedbacks is modest compared to the water vapor feedback, the biogeochemical feedbacks in combination have the potential to substantially increase the climate change associated with any given initial forcing.The views expressed are the author's: They do not express official views of the U.S. Government or the Environmental Protection Agency.  相似文献   

16.
The use of radiative kernels to diagnose climate feedbacks is a recent development that may be applied to existing climate change simulations. We apply the radiative kernel technique to transient simulations from a multi-thousand member perturbed physics ensemble of coupled atmosphere-ocean general circulation models, comparing distributions of model feedbacks with those taken from the CMIP-3 multi GCM ensemble. Although the range of clear sky longwave feedbacks in the perturbed physics ensemble is similar to that seen in the multi-GCM ensemble, the kernel technique underestimates the net clear-sky feedbacks (or the radiative forcing) in some perturbed models with significantly altered humidity distributions. In addition, the compensating relationship between global mean atmospheric lapse rate feedback and water vapor feedback is found to hold in the perturbed physics ensemble, but large differences in relative humidity distributions in the ensemble prevent the compensation from holding at a regional scale. Both ensembles show a similar range of response of global mean net cloud feedback, but the mean of the perturbed physics ensemble is shifted towards more positive values such that none of the perturbed models exhibit a net negative cloud feedback. The perturbed physics ensemble contains fewer models with strong negative shortwave cloud feedbacks and has stronger compensating positive longwave feedbacks. A principal component analysis used to identify dominant modes of feedback variation reveals that the perturbed physics ensemble produces very different modes of climate response to the multi-model ensemble, suggesting that one may not be used as an analog for the other in estimates of uncertainty in future response. Whereas in the multi-model ensemble, the first order variation in cloud feedbacks shows compensation between longwave and shortwave components, in the perturbed physics ensemble the shortwave feedbacks are uncompensated, possibly explaining the larger range of climate sensitivities observed in the perturbed simulations. Regression analysis suggests that the parameters governing cloud formation, convection strength and ice fall speed are the most significant in altering climate feedbacks. Perturbations of oceanic and sulfur cycle parameters have relatively little effect on the atmospheric feedbacks diagnosed by the kernel technique.  相似文献   

17.
黄土高原地区农业生产对气候变化的脆弱性分析   总被引:17,自引:0,他引:17  
根据IPCC定义和实地考察、文献、问卷调查等结果确定了评价黄土高原地区农业生产对气候变化的脆弱性判别指标体系及其权重分配结果,并对几个代表站点做了脆弱性现状评估,为进一步完成黄土高原地区农业生产对气候变化的脆弱性地区分布和对策研究提供了一定的基础和方法。  相似文献   

18.
CMIP5气候模式对中国未来气候变化的预估和应用   总被引:2,自引:0,他引:2  
气候模式是研究气候系统和气候变化的有力工具,其模拟结果是进行气候预测和气候变化风险评估的重要数据基础。随着全球气候变暖速度加快,地表生态环境、水文动态循环过程、社会经济发展等都受到其影响,进而影响到人类的生产和生活。利用气候模式对未来气候变化特征进行评估和预测,可为人类调整发展策略以适应气候变化提供科学依据。通过汇总CMIP5(Coupled Model Intercomparison Project Phase 5)模式在气候变化方面的相关研究,综述了CMIP5气候模式在农业生产、水文动态监控以及其他领域中的应用,最后指出了CMIP5气候模式在模拟预估未来气候变化上存在的不足,并展望了CMIP5气候模式在未来的应用。  相似文献   

19.
青藏高原增暖海拔依赖性研究进展   总被引:2,自引:0,他引:2  
青藏高原平均海拔4000m以上,由于复杂的地形及其特殊的地理位置,对全球气候变化影响重大,已成为研究的热点和关键区.古气候代用指标、常规气象台站以及卫星反演资料表明,青藏高原变暖显著,最低气温升温趋势高于最高气温,冬季增温幅度最大,且存在海拔依赖性,即升温幅度随海拔高度上升而增大.在此基础上,不同大气环流模式试验以及未来气候变化情景下高原气候变化模拟结果也表现出明显的海拔依赖性.而模式资料分析表明,海拔依赖性的存在可能与高海拔地区冰雪反馈和云量有关.但由于青藏高原5000m以上常规观测台站稀少,难以获得连续的气象观测资料,而当前气候系统模式分辨率仍较低,缺乏对复杂地形描述和模拟,这使得海拔依赖性的研究存在一定的争议.因此,当前海拔依赖性研究还存在两个问题:第一,如何获取更高海拔地区的观测和模式资料,运用尽可能多的观测资料来检验海拔依赖性存在与否的问题,如6000m以上站点和格点;第二,如果这种依赖性确实存在,如何从物理机制上解释高原气候变暖的海拔依赖性.  相似文献   

20.
There are a number of sources of uncertainty in regional climate change scenarios. When statistical downscaling is used to obtain regional climate change scenarios, the uncertainty may originate from the uncertainties in the global climate models used, the skill of the statistical model, and the forcing scenarios applied to the global climate model. The uncertainty associated with global climate models can be evaluated by examining the differences in the predictors and in the downscaled climate change scenarios based on a set of different global climate models. When standardized global climate model simulations such as the second phase of the Coupled Model Intercomparison Project (CMIP2) are used, the difference in the downscaled variables mainly reflects differences in the climate models and the natural variability in the simulated climates. It is proposed that the spread of the estimates can be taken as a measure of the uncertainty associated with global climate models. The proposed method is applied to the estimation of global-climate-model-related uncertainty in regional precipitation change scenarios in Sweden. Results from statistical downscaling based on 17 global climate models show that there is an overall increase in annual precipitation all over Sweden although a considerable spread of the changes in the precipitation exists. The general increase can be attributed to the increased large-scale precipitation and the enhanced westerly wind. The estimated uncertainty is nearly independent of region. However, there is a seasonal dependence. The estimates for winter show the highest level of confidence, while the estimates for summer show the least.  相似文献   

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