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1.
Abstract

Strategies to mitigate anthropogenic climate change recognize that carbon sequestration in the terrestrial biosphere can reduce the build-up of carbon dioxide in the Earth's atmosphere. However, climate mitigation policies do not generally incorporate the effects of these changes in the land surface on the surface albedo, the fluxes of sensible and latent heat to the atmosphere, and the distribution of energy within the climate system. Changes in these components of the surface energy budget can affect the local, regional, and global climate. Given the goal of mitigating climate change, it is important to consider all of the effects of changes in terrestrial vegetation and to work toward a better understanding of the full climate system. Acknowledging the importance of land surface change as a component of climate change makes it more challenging to create a system of credits and debits wherein emission or sequestration of carbon in the biosphere is equated with emission of carbon from fossil fuels. Recognition of the complexity of human-caused changes in climate does not, however, weaken the importance of actions that would seek to minimize our disturbance of the Earth's environmental system and that would reduce societal and ecological vulnerability to environmental change and variability.

© 2003 Elsevier Science Ltd. All rights reserved.  相似文献   

2.
The ocean plays a major role in regulating Earth's climate system, and is highly vulnerable to climate change, but continues to receive little attention in the ongoing policymaking designed to mitigate and adapt to global climate change. There are numerous ways to consider the ocean more significantly when developing these policies, several of which offer the co-benefits of biodiversity protection and support of marine-dependent human communities. When developing forward-thinking climate change policy, it is important to understand the ways that the ocean contributes to global climate and to fully inventory the services that the ocean provides to humans. Without more inclusive consideration of the ocean in climate policy, at all levels of governance, policy makers risk weaker than necessary mitigation and adaptation strategies.  相似文献   

3.
利用毫米波云雷达、微波辐射计联合反演方法,对2015年11月11日安徽寿县的一次层状云过程的云参数进行了反演,将所得云参数加入到SBDART辐射传输模式中,进行辐射通量计算,并将计算的地面辐射通量与观测的地面辐射通量进行了对比分析。研究表明:1)利用毫米波雷达和微波辐射计数据联合反演的云参数比较可靠;2)利用SBDART模式并结合反演的云参数,可以准确实时地计算地面及其他高度层的长短波辐射通量;3)在反演的云参数中,光学厚度对地面各种辐射通量的影响是最大的,云层的光学厚度越大,到达地面的太阳短波辐射越小,地面反射短波辐射也越小。另外云底温度越高,云体向下发射的红外长波辐射越大。地面向上的长波辐射是地面温度的普朗克函数,随地面温度而变;4)云对地面的短波辐射强迫为负值,对地面有降温的作用。云对地面的长波辐射强迫是一个正值,对地面有一个增温的作用;5)云对地面的净辐射强迫随时间变化很大,它的正负与太阳高度角和云参数有关。  相似文献   

4.
Abstract

Since the World Climate Change Conference held in the autumn of 2003 in Moscow, Russian Federation, the fate of international climate policy architecture designed around the Kyoto Protocol hangs in the balance. After the withdrawal of the USA from the Kyoto Protocol, the condition of its ratification cannot be met without the Russian Federation. There has been a considerable uncertainty as to Russia's intentions regarding ratification of Kyoto. In this contribution, an attempt is made to identify the Russian motives and concerns, and explain their attitudes regarding the Kyoto Protocol. Pressures against and for ratification are discussed. Finally, a few comments are made about the future of the efforts to solve the global environmental problem of protecting the Earth's climate.  相似文献   

5.
通过温室气体排放和土地利用/覆盖变化,人类活动对气候变化产生显著影响。为了探究在不同温室气体浓度(Greenhouse gas concentration,GHG)背景下,相同的土地利用/覆盖变化(Land Use and Land Cover Change,LULCC)对于欧洲区域气候的影响差异,采用CESM(Community Earth System Model)耦合模式进行了模拟研究。研究发现,在1850年温室气体浓度背景下,土地利用/覆盖变化导致欧洲中东部地区降水显著增加,而在2000年温室气体浓度背景下,土地利用/覆盖变化导致欧洲中东部地区降水减少。温室气体增加后,LULCC导致该地区对流层低层大气环流由辐合变为辐散,气温以及大气水汽含量降低,这些变化能较大程度的改变LULCC对区域降水的净影响力。  相似文献   

6.
气候系统的非平稳行为和预测理论   总被引:22,自引:5,他引:17  
杨培才  周秀骥 《气象学报》2005,63(5):556-570
到目前为止,有关非平稳复杂系统及其在气候预测中的应用研究(它有着比混沌系统更为复杂的行为)是一个较少被人理解并有重大科学意义的前瞻性研究课题。在大气运动中,气候正是一个典型的非平稳系统,但是现有的气候预测理论,包括统计预测理论和非线性预测理论,几乎都无一例外地建立在平稳性假定的基础之上,这有悖于气候过程的基本性质,因此它有可能是导致气候预测水平低下的重要的理论原因。另外,近10年来,气候过程具有层次结构已经成为许多科学家的共识,但是如何发展和完善这一理论,使之成为一个完整的体系,人们似乎还没找到合适的途径。事实上,气候系统的多层次结构(它与通常的多尺度结构是两个完全不同的概念)正是产生非平稳行为的原因,而气候系统的非平稳特性正是层次结构的集中表现。在这样的思想指导下,文中系统地讨论了非平稳气候的一些基本问题和相应的预测理论,并为之搭起了一个初步的理论框架。  相似文献   

7.
利用国际古气候模拟对比计划第四阶段的多模式结果,分析了末次间冰期亚洲中部干旱区的干湿变化及机制。多模式集合平均结果表明,末次间冰期亚洲中部干旱区年降水减少0.7%,其中中亚地区的年降水减少2.8%,新疆地区年降水增加1.8%。水汽收支方程表明,末次间冰期中亚地区在雨季(冬春季)的降水变化主要与垂直动力项有关,新疆地区在雨季(夏季)的降水变化主要与垂直动力与热力项有关。此外,基于Penman-Montieth方法计算的亚洲中部干旱区的干旱指数在末次间冰期减小约10.2%,表明末次间冰期亚洲中部干旱区气候明显变干且存在旱区扩张的现象,这主要受到潜在蒸散变化的调控。潜在蒸散的增加进一步受到有效能量增加与地面风速增大的调控。本研究从模拟的角度揭示了末次间冰期亚洲中部干旱区干湿变化的可能特征及机制,在一定程度上有助于理解旱区气候在增暖情景下对轨道参数的响应特征。  相似文献   

8.
RegCM4对中国东部区域气候模拟的辐射收支分析   总被引:2,自引:0,他引:2       下载免费PDF全文
利用卫星和再分析数据,评估了区域气候模式Reg CM4对中国东部地区辐射收支的基本模拟能力,重点关注地表净短波(SNS)、地表净长波(SNL)、大气顶净短波(TNS)、大气顶净长波(TNL)4个辐射分量。结果表明:1)短波辐射的误差值在夏季较大,而长波辐射的误差值在冬季较大。但各辐射分量模拟误差的空间分布在冬、夏季都有较好的一致性。2)对于地表辐射通量,SNS表现为正偏差(向下净短波偏多),在各分量中误差最大,区域平均误差值近50 W/m2;SNL表现为负偏差(向上净长波偏多);对于大气顶辐射通量,TNS和TNL分别表现为"北负南正"的误差分布和整体正偏差。3)利用空间相关和散点线性回归方法对4个辐射分量的模拟误差进行归因分析,发现在云量、地表反照率、地表温度三个直接影响因子中,云量模拟误差的贡献最大,中国东部地区云量模拟显著偏少。  相似文献   

9.
10.
11.
Recent studies have estimated the magnitude of climate feedback based on the correlation between time variations in outgoing radiation flux and sea surface temperature (SST). This study investigates the influence of the natural non-feedback variation (noise) of the flux occurring independently of SST on the determination of climate feedback. The observed global monthly radiation flux is used from the Clouds and the Earth's Radiant Energy System (CERES) for the period 2000–2008. In the observations, the time lag correlation of radiation and SST shows a distorted curve with low statistical significance for shortwave radiation while a significant maximum at zero lag for longwave radiation over the tropics. This observational feature is explained by simulations with an idealized energy balance model where we see that the non-feedback variation plays the most significant role in distorting the curve in the lagged correlation graph, thus obscuring the exact value of climate feedback. We also demonstrate that the climate feedback from the tropical longwave radiation in the CERES data is not significantly affected by the noise. We further estimate the standard deviation of radiative forcings (mainly from the noise) relative to that of the non-radiative forcings, i.e., the noise level from the observations and atmosphere–ocean coupled climate model simulations in the framework of the simple model. The estimated noise levels in both CERES (>13 %) and climate models (11–28 %) are found to be far above the critical level (~5 %) that begins to misrepresent climate feedback.  相似文献   

12.
Part Ⅱ of this study detects the dominant decadal-centennial timescales in four SST indices up to the 2010/2011 winter and tries to relate them to the observed 11-yr and 88-yr solar activity with the sunspot number up to Solar Cycle 24.To explore plausible solar origins of the observed decadal-centennial timescales in the SSTs and climate variability in general,we design a simple one-dimensional dynamical system forced by an annual cycle modulated by a small-amplitude single-or multi-scale "solar activity." Results suggest that nonlinear harmonic and subharmonic resonance of the system to the forcing and period-doubling bifurcations are responsible for the dominant timescales in the system,including the 60-yr timescale that dominates the Atlantic Multidecadal Oscillation.The dominant timescales in the forced system depend on the system’s parameter setting.Scale enhancement among the dominant response timescales may result in dramatic amplifications over a few decades and extreme values of the time series on various timescales.Three possible energy sources for such amplifications and extremes are proposed.Dynamical model results suggest that solar activity may play an important yet not well recognized role in the observed decadal-centennial climate variability.The atmospheric dynamical amplifying mechanism shown in Part Ⅰ and the nonlinear resonant and bifurcation mechanisms shown in Part Ⅱ help us to understand the solar source of the multi-scale climate change in the 20th century and the fact that different solar influenced dominant timescales for recurrent climate extremes for a given region or a parameter setting.Part Ⅱ also indicates that solar influences on climate cannot be linearly compared with non-cyclic or sporadic thermal forcings because they cannot exert their influences on climate in the same way as the sun does.  相似文献   

13.
Global warming and accompanying climate change may be caused by an increase in atmospheric greenhouse gasses generated by anthropogenic activities. In order to supply such a mechanism of global warming with a quantitative underpinning, we need to understand the multifaceted roles of the Earth's energy balance and material cycles. In this study, we propose a new one-dimensional simple Earth system model. The model consists of carbon and energy balance submodels with a north–south zonal structure. The two submodels are coupled by interactive feedback processes such as CO2 fertilization of net primary production (NPP) and temperature dependencies of NPP, soil respiration, and ocean surface chemistry. The most important characteristics of the model are not only that the model requires a relatively short calculation time for carbon and energy simulation compared with a General Circulation Model (GCM) and an Earth system Model of Intermediate Complexity (EMIC), but also that the model can simulate average latitudinal variations. In order to analyze the response of the Earth system due to increasing greenhouse gasses, several simulations were conducted in one dimension from the years 1750 to 2000. Evaluating terrestrial and oceanic carbon uptake output of the model in the meridional direction through comparison with observations and satellite data, we analyzed the time variation patterns of air temperature in low- and middle-latitude belts. The model successfully reproduced the temporal variation in each latitude belt and the latitudinal distribution pattern of carbon uptake. Therefore, this model could more accurately demonstrate a difference in the latitudinal response of air temperature than existing models. As a result of the model evaluations, we concluded that this new one-dimensional simple Earth system model is a good tool for conducting global warming simulations. From future projections using various emission scenarios, we showed that the spatial distribution of terrestrial carbon uptake may vary greatly, not only among models used for climate change simulations, but also amongst emission scenarios.  相似文献   

14.
The effects of Earth's rotation on convection into stratified fluid under uniform surface cooling are investigated using a large-eddy simulation (LES) model. The initial mixed layer depth varies by a factor of 40 and temperature gradient below the mixed layer varies by three orders of magnitude. At the end of integration (typically 20–40 inertial periods), the so-called natural Rossby number for the rotating experiments varies from 0.06 to 2. The wide range of conditions used is designed to extract scaling laws of rotating convection and to shed light on the importance of Earth's rotation on convection. It is found that the effects of rotation can be characterized by a series of hyperbolic tangent functions of the natural Rossby number. The effects of rotation are most pronounced when Ro is order 0.1 or less. For Ro  1, the effects of rotation become small. Comparison of Lagrangian statistics of numerical floats reveals that horizontal mixing is suppressed in the presence of rotation. This result is consistent with the finding that integral length scale and turbulent intensity decrease when rotation is included, in contrast to the conclusion of an early study that argued for increased horizontal mixing in the presence of rotation.  相似文献   

15.
气侯层次和分数维   总被引:3,自引:0,他引:3       下载免费PDF全文
本文应用非线性理论分析了多层次的气候系统,指出分数维是气候系统结构的特征,是气候系统中尺度变换后的不变量。分数维可用于平滑气候资料,滤掉尺度较小的振动,形成较高的气候层次。平滑前后的气候层次结构已不相同。低层次气候变化的规律很不确定,在高层次上看就比较确定了。高、低层次之间存在非线性的相互作用。以上是气候研究中的一些基本问题,本文用我国的气候资料对此作了初步的探讨。  相似文献   

16.
城市气象研究进展   总被引:5,自引:0,他引:5  
中国数十年来在城市气象研究这一新兴学科领域开展了大量研究并获得了多方面的丰硕成果。文中从城市气象观测网与观测试验、城市气象多尺度模式、城市气象与大气环境相互影响、城市化对天气气候的影响等4个方面论述了城市气象的主要研究进展:中国各大城市已建立或正在完善具有多平台、多变量、多尺度、多重链接、多功能等特点的城市气象综合观测网;北京、南京、上海等地开展了大型城市气象观测科学试验,被世界气象组织列入研究示范项目;成功开展了风洞实验、缩尺度外场实验研究;建立了多尺度城市气象和空气质量预报数值模式,并应用于业务;在城市热岛效应、城市对降水影响、城市气象与城市规划、城市化对区域气候及空气质量的影响、城市气象与大气环境相互作用等研究领域取得长足进展。最后指出,未来需要重点从新观测技术及观测资料同化应用、城市系统模式研究、城市化对天气气候的影响机理、城市化对大气环境和人体健康的影响、城市水文气象气候与环境综合服务等方面开展科学研究与应用,为中国城市化、生态文明建设、防灾减灾和应对气候变化等国家需求提供科技支撑。   相似文献   

17.
Mountain observatories around the world are unique sites for monitoring and investigating variations, trends, forcings and feedbacks in the climate system, which are of utmost interest for understanding global climate change. From the small number of these research platforms, Sonnblick Observatory (Austrian Alps) stands out because of its long time series dating back to 1886 at an elevation of 3,100?m a.s.l. The paper describes the contribution of mountain observatories to climatology by the example of Sonnblick Observatory. The observatory's scientific evolution is summarised, starting from the original idea of upper air atmospheric measurements to its recent role as an atmospheric background station and interdisciplinary research site.  相似文献   

18.
由于地球磁场的影响,电磁编队可以在近地轨道稳定飞行,通过改变电磁卫星磁极的电流大小来保持一定的编队队形.虽然地球磁场通常被看作偶极场,并随地球旋转,但地球磁场与电磁力场之间的相互作用被认为是一种内力.当电磁卫星编队突然遇到障碍物需要积极避障时,电磁力作为内力不能改变编队方向,因此,必须对电磁卫星编队施加外力,以实现碰撞规避控制.本文研究了电推进技术在电磁卫星编队碰撞规避中的应用.在此过程中,电推进提供编队转向所需的外部推力,而电磁力作为辅助推力共同作用实现碰撞规避.电推进采用多模态霍尔推力器,基于模糊推断的LQR重构控制方法进行碰撞规避过程的控制,并通过数字仿真验证了控制方法的有效性.  相似文献   

19.
Variability in local weather patterns has long been suggested as a major barrier impeding laypeople from recognizing long-term climate trends. However, as humans are able to detect and interpret rapid signal fluctuations, it seems psychologically plausible to assume that they are able to integrate short-term variations of weather variables into their mental representations of climate change. Using a combined analysis of social media and weather station data, here we investigated the impact of the short-term volatility of local temperature on climate change-related tweets from 2014 to 2017. We found a nonlinear hockey stick relationship between weekly temperature volatility and climate change-related tweets, a volatility rise of 1 °C corresponds to an 82% increase in climate change tweets when volatility is above 3.5 °C. This volatility effect was observed from 2016 onwards, suggesting a recent change in people’s mental representations of climate change. This study provides empirical evidence illustrating that in the public mind, climate change may not be represented as a mere temperature increase any more, but as a disruption of the climate system in general.  相似文献   

20.
明确气候变化背景下大兴安岭林区气候干湿状况特征,揭示其对森林火灾的影响,可为该区域森林火灾管理和森林资源保护提供科学依据。基于大兴安岭林区1974—2016年标准化降水指数(SPI),采用统计分析和对比分析方法,系统研究不同干湿情景对森林火灾发生次数及过火面积的影响,并讨论不同等级干旱对其影响的异同性。结果表明:1974—2016年,年、季尺度上大兴安岭林区气候均呈湿润化趋势。森林火灾发生次数多(少)和过火面积大(小)与气候的干湿状况(等级)基本一致,但森林火灾的发生次数与气候干湿状况相关更为密切。年尺度上,SPI与火灾次数呈负相关,与过火面积的自然对数则呈较弱的负相关;季尺度上,各季节SPI与对应的林火次数和过火面积自然对数均呈显著的负相关,但与过火面积的相关程度差异较大,以春季相关最为显著,秋季次之,夏季则相对较弱;不同季节SPI与年林火次数和过火面积自然对数呈负相关,前一年冬季SPI对当年火灾次数的贡献最大。可见,气候干湿状况对森林火灾的影响存在明显的滞后效应。SPI不仅能较好地反映区域气候的干湿状况,亦能较好地指示森林火灾发生的可能性及发生火灾的过火面积的相对变化情况,可为森林火灾预测和管理提供科学依据。  相似文献   

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