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1.
Numerical Simulation of Global Temperature Change during the 20th Century with the IAP／LASG GOALS Model 总被引：1，自引：0，他引：1
The IAP/LASG GOALS coupled model is used to simulate the climate change during the 20th century using historical greenhouse gases concentrations, the mass mixing ratio of sulfate aerosols simulated by a CTM model, and reconstruction of solar variability spanning the period 1900 to 1997. Four simulations, including a control simulation and three forcing simulations, are conducted. Comparison with the observational record for the period indicates that the three forcing experiments simulate reasonable temporal and spatial distributions of the temperature change. The global warming during the 20th century is caused mainly by increasing greenhouse gas concentration especially since the late 1980s; sulfate aerosols offset a portion of the global warming and the reduction of global temperature is up to about 0.11℃ over the century; additionally, the effect of solar variability is not negligible in the simulation of climate change over the 20th century. 相似文献
2.
太阳是地球流体(大气和海洋等)运动的最终能量源,地球环境,尤其是气候的变化不能不与太阳活动有关.目前,普遍将全球增暖归结为温室气体含量增加所导致的温室效应的加剧,这无疑是有一定依据和有道理的.但从科学上来讲,人类活动所引起温室气体增加的影响,并非是唯一原因.基于已有的一些研究结果,从太阳活动的观点所进行的初步分析表明,太阳活动也可能是引起近世纪全球增暖的另一个重要原因.太阳活动的影响主要包括太阳辐射的直接影响和引发地磁场变化的间接影响两个方面,地球磁场的变化将可通过动力过程和热力过程而影响大气环流和气候的变化. 相似文献
3.
G. C. Hegerl K. Hasselmann U. Cubasch J. F. B. Mitchell E. Roeckner R. Voss J. Waszkewitz 《Climate Dynamics》1997,13(9):613-634
A multi-fingerprint analysis is applied to the detection and attribution of anthropogenic climate change. While a single
fingerprint is optimal for the detection of climate change, further tests of the statistical consistency of the detected climate
change signal with model predictions for different candidate forcing mechanisms require the simultaneous application of several
fingerprints. Model-predicted climate change signals are derived from three anthropogenic global warming simulations for the
period 1880 to 2049 and two simulations forced by estimated changes in solar radiation from 1700 to 1992. In the first global
warming simulation, the forcing is by greenhouse gas only, while in the remaining two simulations the direct influence of
sulfate aerosols is also included. From the climate change signals of the greenhouse gas only and the average of the two greenhouse
gas-plus-aerosol simulations, two optimized fingerprint patterns are derived by weighting the model-predicted climate change
patterns towards low-noise directions. The optimized fingerprint patterns are then applied as a filter to the observed near-surface
temperature trend patterns, yielding several detection variables. The space-time structure of natural climate variability
needed to determine the optimal fingerprint pattern and the resultant signal-to-noise ratio of the detection variable is estimated
from several multi-century control simulations with different CGCMs and from instrumental data over the last 136 y. Applying
the combined greenhouse gas-plus-aerosol fingerprint in the same way as the greenhouse gas only fingerprint in a previous
work, the recent 30-y trends (1966–1995) of annual mean near surface temperature are again found to represent a significant
climate change at the 97.5% confidence level. However, using both the greenhouse gas and the combined forcing fingerprints
in a two-pattern analysis, a substantially better agreement between observations and the climate model prediction is found
for the combined forcing simulation. Anticipating that the influence of the aerosol forcing is strongest for longer term temperature
trends in summer, application of the detection and attribution test to the latest observed 50-y trend pattern of summer temperature
yielded statistical consistency with the greenhouse gas-plus-aerosol simulation with respect to both the pattern and amplitude
of the signal. In contrast, the observations are inconsistent with the greenhouse-gas only climate change signal at a 95%
confidence level for all estimates of climate variability. The observed trend 1943–1992 is furthermore inconsistent with a
hypothesized solar radiation change alone at an estimated 90% confidence level. Thus, in contrast to the single pattern analysis,
the two pattern analysis is able to discriminate between different forcing hypotheses in the observed climate change signal.
The results are subject to uncertainties associated with the forcing history, which is poorly known for the solar and aerosol
forcing, the possible omission of other important forcings, and inevitable model errors in the computation of the response
to the forcing. Further uncertainties in the estimated significance levels arise from the use of model internal variability
simulations and relatively short instrumental observations (after subtraction of an estimated greenhouse gas signal) to estimate
the natural climate variability. The resulting confidence limits accordingly vary for different estimates using different
variability data. Despite these uncertainties, however, we consider our results sufficiently robust to have some confidence
in our finding that the observed climate change is consistent with a combined greenhouse gas and aerosol forcing, but inconsistent
with greenhouse gas or solar forcing alone.
Received: 28 April 1996 / Accepted: 27 January 1997 相似文献
4.
气候变化的归因与预估模拟研究 总被引：14，自引：2，他引：12
本文总结了近五年来中国科学院大气物理研究所在气候变暖的归因模拟与预估研究上的主要进展。研究表明,利用海温、太阳辐射和温室气体等实际强迫因子驱动大气环流模式,能够较为合理地模拟全球平均地表气温在20世纪的演变,但是难以模拟出包括北大西洋涛动／北极涛动和南极涛动在内的高纬度环流的长期变化趋势。利用温室气体和硫酸盐气溶胶等“历史资料”驱动气候系统模式,能够较好地模拟出20世纪后期的全球增暖,但如果要再现20世纪前期(1940年代)的变暖,还需同时考虑太阳辐射等自然外强迫因子。20世纪中国气温演变的耦合模式模拟技巧,较之全球平均情况要低;中国气候在1920年代的变暖机理目前尚不清楚。对于近50年中国东部地区“南冷北暖”、“南涝北旱”的气候变化,基于大气环流模式特别是区域气候模式的数值试验表明,夏季硫酸盐气溶胶的负辐射效应超过了温室气体的增暖效应,从而对变冷产生贡献。但现有的数值模拟证据,不足以说明气溶胶增加对“南涝北旱”型降水异常有贡献。20世纪中期以来,青藏高原主体存在明显增温趋势,温室气体浓度的增加对这种增暖有显著贡献。多模式集合预估的未来气候变化表明,21世纪全球平均温度将继续增暖,增温幅度因不同排放情景而异;中国大陆年均表面气温的增暖与全球同步,但增幅在东北、西部和华中地区较大,冬季升温幅度高于夏季、日最低温度升幅要强于日最高温度;全球增暖有可能对我国中东部植被的地理分布产生影响。伴随温室气体增加所导致的夏季平均温度升高,极端温度事件增多;在更暖的气候背景下,中国大部分地区总降水将增多,极端降水强度加大且更频繁发生,极端降水占总降水的比例也将增大。全球增暖有可能令大洋热盐环流减弱,但是减弱的幅度因模式而异。全球增暖可能不是导致北太平洋副热带－热带经圈环流自20世纪70年代以来变弱的原因。文章同时指出了模式预估结果中存在的不确定性。 相似文献
5.
The East Asian summer monsoon (EASM) circulation and summer rainfall over East China have experienced large decadal changes
during the latter half of the 20th century. To investigate the potential causes behind these changes, a series of simulations
using the national center for atmospheric research (NCAR) community atmospheric model version 3 (CAM3) and the geophysical
fluid dynamics laboratory (GFDL) atmospheric model version 2.1 (AM2.1) are analyzed. These simulations are forced separately
with different historical forcing, namely tropical sea surface temperature (SSTs), global SSTs, greenhouse gases plus aerosols,
and a combination of global SSTs and greenhouse gases plus aerosols. This study focuses on the relative roles of these individual
forcings in causing the observed monsoon and rainfall changes over East Asia during 1950–2000. The simulations from both models
show that the SST forcing, primarily from the Tropics, is able to induce most of the observed weakening of the EASM circulation,
while the greenhouse gas plus (direct) aerosol forcing increases the land-sea thermal contrast and thus enhances the EASM
circulation. The results suggest that the recent warming in the Tropics, especially the warming associated with the tropical
interdecadal variability centered over the central and eastern Pacific, is a primary cause for the weakening of the EASM since
the late 1970s. However, a realistic simulation of the relatively small-scale rainfall change pattern over East China remains
a challenge for the global models. 相似文献
6.
Hyung-Gyu Lim Sang-Wook Yeh Ji-Won Kim Rokjin Park Chang-Keun Song 《Meteorology and Atmospheric Physics》2014,126(1-2):71-79
Due to the dramatic increase in the global mean surface temperature (GMST) during the twentieth century, the climate science community has endeavored to determine which mechanisms are responsible for global warming. By analyzing a millennium simulation (the period of 1000–1990 ad) of a global climate model and global climate proxy network dataset, we estimate the contribution of solar and greenhouse gas forcings on the increase in GMST during the present warm period (1891–1990 ad). Linear regression analysis reveals that both solar and greenhouse gas forcing considerably explain the increase in global mean temperature during the present warm period, respectively, in the global climate model. Using the global climate proxy network dataset, on the other hand, statistical approach suggests that the contribution of greenhouse gas forcing is slightly larger than that of solar forcing to the increase in global mean temperature during the present warm period. Overall, our result indicates that the solar forcing as well as the anthropogenic greenhouse gas forcing plays an important role to increase the global mean temperature during the present warm period. 相似文献
7.
The mechanism responsible for Indian Ocean Sea surface temperature (SST) basin-wide warming trend during 1958–2004 is studied based on both observational data analysis and numerical experiments with a climate system model FGOALS-gl. To quantitatively estimate the relative contributions of external forcing (anthropogenic and natural forcing) and internal variability, three sets of numerical experiments are conducted, viz. an all forcing run forced by both anthropogenic forcing (greenhouse gases and sulfate aerosols) and natural forcing (solar constant and volcanic aerosols), a natural forcing run driven by only natural forcing, and a pre-industrial control run. The model results are compared to the observations. The results show that the observed warming trend during 1958–2004 (0.5 K (47-year)?1) is largely attributed to the external forcing (more than 90 % of the total trend), while the residual is attributed to the internal variability. Model results indicate that the anthropogenic forcing accounts for approximately 98.8 % contribution of the external forcing trend. Heat budget analysis shows that the surface latent heat flux due to atmosphere and surface longwave radiation, which are mainly associated with anthropogenic forcing, are in favor of the basin-wide warming trend. The basin-wide warming is not spatially uniform, but with an equatorial IOD-like pattern in climate model. The atmospheric processes, oceanic processes and climatological latent heat flux together form an equatorial IOD-like warming pattern, and the oceanic process is the most important in forming the zonal dipole pattern. Both the anthropogenic forcing and natural forcing result in easterly wind anomalies over the equator, which reduce the wind speed, thereby lead to less evaporation and warmer SST in the equatorial western basin. Based on Bjerknes feedback, the easterly wind anomalies uplift the thermocline, which is unfavorable to SST warming in the eastern basin, and contribute to SST warming via deeper thermocline in the western basin. The easterly anomalies also drive westward anomalous equatorial currents, against the eastward climatology currents, which is in favor of the SST warming in the western basin via anomalous warm advection. Therefore, both the atmospheric and oceanic processes are in favor of the IOD-like warming pattern formation over the equator. 相似文献
8.
全球变暖趋缓研究进展 总被引：16，自引：5，他引：11
近十几年来,全球年平均表面温度上升趋势显示出停滞状态,即全球变暖趋缓,这引起了国际社会的广泛关注,同时也引发了对全球变暖的质疑,各国气候学家正努力就全球变暖趋缓的事实、原因及其可能影响展开研究。本文综述了目前国内外对全球变暖趋缓的研究结果。多数科学家认可近十几年来全球变暖停滞的事实,并认为太阳活动处于低位相、大气气溶胶（自然和人为）增加以及海洋吸收热量是变暖停滞的可能影响因子,其中海洋（尤其是700米以下的深海）对热量的储存可能是变暖停滞的关键。国际耦合模式比较计划第5阶段中的模式并未精确地描述各种有利降温影响因子的近期位相演变,因而其模拟的近期增暖趋势较观测偏强。由此推断,变暖停滞主要是自然因素造成的,并且预测变暖趋缓将在近几年或几十年内结束（依赖于太平洋年代际振荡的位相转变）,未来气温将仍主要受到温室气体增加的影响而表现出明显的上升趋势。因此,目前的全球变暖趋缓不大可能改变到本世纪末全球大幅度变暖带来的风险。本综述展望未来的研究热点包括:精确估算全球气温和海洋热含量的变率及其不确定性,海洋年代际信号（太平洋以及大西洋的年代际振荡）的转型机制,存储在深海的热量将在何时返回海洋表面及其对区域气候的潜在影响。 相似文献
9.
In this study, the contributions from changes in man-made greenhouse gases (GHG), anthropogenic aerosols (AA), and land use (LU), as well as natural solar and volcanic (NAT) forcing changes, to observed changes in surface air temperature (T) and precipitation (P) over global land, especially over arid-semiarid areas, during 1946–2005 are quantified using observations and climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Results show that the anthropogenic (ANT) forcings dominate the ubiquitous surface warming seen in observations and lead to slight increases in precipitation over most land areas, while the NAT forcing leads to small cooling over land. GHG increases are the primary factor responsible for the anthropogenic climate change, while the AA forcing offsets a large part of the GHG-induced warming and P changes. The LU forcing generally contributes little to the T and P changes from 1946 to 2005 over most land areas. Unlike the consistent temperature changes among most model simulations, precipitation changes display a large spread among the models and are incomparable with the observations in spatial distributions and magnitude, mainly due to its large internal variability that varies among individual model runs. Using an optimal fingerprinting method, we find that the observed warming over land during 1946–2005 can be largely attributed to the ANT forcings, and the combination of the ANT and NAT forcings can explain about 85~95% of the observed warming trend over global land as well as over most arid-semiarid regions such as Northern China. However, the anthropogenic influences on precipitation over the past 60 years are generally undetectable over most land areas, including most arid-semiarid regions. This indicates that internal variability is still larger than the forced change for land precipitation. 相似文献
10.
Numerical experiments have been carried out with a two-dimensional sector averaged global climate model in order to assess the potential impact of solar variability on the Earth's surface temperature from 1700 to 1992. This was done by investigating the model response to the variations in solar radiation caused by the changes in the Earth's orbital elements, as well as by the changes intrinsic to the Sun. In the absence of a full physical theory able to explain the origin of the observed total solar irradiance variations, three different total solar irradiance reconstructions have been used. A total solar irradiance change due to the photospheric effects incorporated in the Willson and Hudson (1988) parameterization, and the newly reconstructed solar total irradiance variations from the solar models of Hoyt and Schatten (1993) and Lean et al. (1995). Our results indicate that while the influence of the orbital forcing on the annual and global mean surface temperature is negligible at the century time scale, the monthly mean response to this forcing can be quite different from one month to another. The modelled global warming due to the three investigated total solar irradiance reconstructions is insufficient to reproduce the observed 20th century warming. Nevertheless, our simulated surface temperature response to the changes in the Sun's radiant energy output suggests that the Gleissberg cycle (88 years) solar forcing should not be neglected in explaining the century-scale climate variations. Finally, spectral analysis seems to point out that the 10- to 12-year oscillations found in the recorded Northern Hemisphere temperature variations from 1700 to 1992 could be unrelated to the solar forcing. Such a result could indicate that the eleven-year period which is frequently found in climate data might be related to oscillations in the atmosphere or oceans, internal to the climate system. 相似文献
11.
Decreasing Trend in Global Land Monsoon Precipitation over the Past 50 Years Simulated by a Coupled Climate Model 总被引：1，自引：0，他引：1
The authors examine the effects of external forcing agents such as greenhouse gases (GHGs) and aerosols, as well as solar variability and ozone, on global land monsoon precipitation by using a coupled climate model HadGEM1, which was developed by the Met Office Hadley Centre for Climate Research. The results indicate that HadGEM1 performs well in simulating the observed decreasing trend of global land monsoon precipitation over the past 50 years. This trend mainly occurred in the Northern Hemisphere and is ... 相似文献
12.
G. C. Hegerl P. A. Stott M. R. Allen J. F. B. Mitchell S. F. B. Tett U. Cubasch 《Climate Dynamics》2000,16(10-11):737-754
Fingerprint techniques for the detection of anthropogenic climate change aim to distinguish the climate response to anthropogenic forcing from responses to other external influences and from internal climate variability. All these responses and the characteristics of internal variability are typically estimated from climate model data. We evaluate the sensitivity of detection and attribution results to the use of response and variability estimates from two different coupled ocean atmosphere general circulation models (HadCM2, developed at the Hadley Centre, and ECHAM3/LSG from the MPI für Meteorologie and Deutsches Klimarechenzentrum). The models differ in their response to greenhouse gas and direct sulfate aerosol forcing and also in the structure of their internal variability. This leads to differences in the estimated amplitude and the significance level of anthropogenic signals in observed 50-year summer (June, July, August) surface temperature trends. While the detection of anthropogenic influence on climate is robust to intermodel differences, our ability to discriminate between the greenhouse gas and the sulfate aerosol signals is not. An analysis of the recent warming, and the warming that occurred in the first half of the twentieth century, suggests that simulations forced with combined changes in natural (solar and volcanic) and anthropogenic (greenhouse gas and sulfate aerosol) forcings agree best with the observations. 相似文献
13.
工业革命以来人类活动带来的温室气体日益增加,导致全球气温持续升高。然而,1998年以来全球变暖出现了停滞(hiatus)现象。本文回顾了近年来有关全球变暖停滞的研究进展,着重讨论变暖停滞的物理机制。目前有关变暖停滞的机制有两种观点:一种观点认为全球变暖停滞是由于外强迫造成的,另一种则认为是自然变率产生的。外强迫的观点主要归结为太阳活动强迫、火山喷发气溶胶强迫、人类活动产生的气溶胶强迫以及平流层水汽强迫四种作用。自然变率的观点则认为人类活动产生的多余热量进入到深海,尤其是海表700 m以下,且认为主要是由于海洋的作用。持这种观点的又分两种意见,一种认为是太平洋年代际振荡的影响,尤其是赤道东太平洋海表温度变冷;另一种则认为是大西洋经向翻转流的影响。目前主流观点认为,自然变率是产生全球变暖停滞的主要机制,人类活动产生的多余热量进入到深海,不过多余热量进入哪些海域尚存争议。 相似文献
14.
Climate sensitivity to cloud optical properties 总被引：1，自引：0，他引：1
A radiative–convective model was developed to investigate the sensitivity of climate to cloud optical properties and the related feedback processes. This model demonstrates that the Earth's surface temperature increases with cloud optical depth when the clouds are very thin but decreases with cloud optical depth when the cloud shortwave (solar) radiative forcing is larger than the cloud longwave (terrestrial) radiative forcing. When clouds are included in the model, the magnitude of the greenhouse effect due to a doubling of the CO2 concentration varies with the cloudoptical depth: the thicker the clouds, the weaker the greenhouse warming. In addition, a small variation in the cloud droplet size has a larger impact on the equilibrium state temperature in the lower atmosphere than the warming caused by a doubling of the CO2 concentration: a 2% increase in the average cloud droplet size per degree increase in temperature doubles the warming caused by the doubling of the CO2 concentration. These findings suggest that physically reliable correlations between the cloud droplet size and macrophysical meteorological variables such as temperature, wind and water vapor fields are needed on a global climate scale to assess the climate impact of increases in greenhouse gases. 相似文献
15.
When greenhouse gases are increased in coupled GCM experiments there is both a direct effect and an indirect effect due to changes in the surface conditions. In this study we carry out experiments with a perpetual winter atmosphere only model in order to investigate the influence of changes to the surface conditions (sea surface temperatures, sea-ice and snow amount) on the Northern Hemisphere winter mid-latitude mean sea level pressure response. The surface conditions for the perpetual winter model experiments are prescribed from time averages of the HadCM2 control and greenhouse gas experiments. Forcing the perpetual winter model with the HadCM2 greenhouse gas surface conditions produces a negative mean sea level pressure (MSLP) response across both Northern Hemisphere ocean basins, as was found in the coupled model HadCM2 experiment. Additional PW model experiments show that the sea surface temperature forcing from the HadCM2 greenhouse gas experiment dominates the snow and soil moisture content forcings. The sea-ice forcing from the HadCM2 greenhouse gas experiment reduces MSLP at high latitudes. In the north Pacific region MSLP decreases when the global mean warming is applied to the sea surface temperature forcing field at all open sea points. In the north Atlantic region the increased tropics to mid-latitude meridional sea surface temperature gradient is required for MSLP to decrease. These experiments show that the MSLP response in the Northern Hemisphere mid-latitude storm track regions is sensitive to the non-local sea surface temperature anomaly pattern. 相似文献
16.
Fangxing Tian Buwen Dong Jon Robson Rowan Sutton Laura Wilcox 《Climate Dynamics》2020,54(9):3959-3975
In the period 1960–2010, the land surface air temperature (SAT) warmed more rapidly over some regions relative to the global mean. Using a set of time-slice experiments, we highlight how different physical processes shape the regional pattern of SAT warming. The results indicate an essential role of anthropogenic forcing in regional SAT changes from the 1970s to 2000s, and show that both surface–atmosphere interactions and large-scale atmospheric circulation changes can shape regional responses to forcing. Single forcing experiments show that an increase in greenhouse gases can lead to regional changes in land surface warming in winter (DJF) due to snow-albedo feedbacks, and in summer (JJA) due to soil-moisture and cloud feedbacks. Changes in anthropogenic aerosol and precursor (AA) emissions induce large spatial variations in SAT, characterized by warming over western Europe, Eurasia, and Alaska. In western Europe, SAT warming is stronger in JJA than in DJF due to substantial increases in clear sky shortwave radiation over Europe, associated with decreases in local AA emissions since the 1980s. In Alaska, the amplified SAT warming in DJF is due to increased downward longwave radiation, which is related to increased water vapor and cloud cover. In this case, although the model was able to capture the regional pattern of SAT change, and the associated local processes, it did not simulate all processes and anomalies correctly. For the Alaskan warming, the model is seen to achieve the correct regional response in the context of a wider North Pacific anomaly that is not consistent with observations. This demonstrates the importance of model evaluation that goes beyond the target variable in detection and attribution studies. 相似文献
17.
Progress in the attribution of climate warming in China for the 20th century is summarized. Three sets of climate model experiments including both coupled and uncoupled runs have been used in the attribution analyses. Comparison of climate model results with the observations proves that in the 20th century, especially in the recent half century, climate warming in China is closely related to the increasing of the anthropogenic emissions of greenhouse gases, while sulfate aerosol should also have contributions. When both external forcing and natural forcing agents are prescribed, coupled climate models have better results in producing the observed variation of temperature in China. The role of oceanic forcing is also emphasized in the attribution analyses. The observed climate warming of China in the 1920s could not be reproduced in any set of climate model simulations. 相似文献
18.
This paper demonstrates that there is a robust statistical relationship between the records of the global mean surface air temperature and the atmospheric concentration of carbon dioxide over the period 1870–1991. As such, the enhanced greenhouse effect is a plausible explanation for the observed global warming. Long term natural variability is another prime candidate for explaining the temperature rise of the last century. Analysis of natural variability from paleo-reconstructions, however, shows that human activity is so much more likely an explanation that the earlier conclusion is not refuted. But, even if one believes in large natural climatic variability, the odds are invariably in favour of the enhanced greenhouse effect. The above conclusions hold for a range of statistical models, including one that is capable of describing the stabilization of the global mean temperature from the 1940s to the 1970s onwards. This model is also shown to be otherwise statistically adequate. The estimated climate sensitivity is about 3.8 °C with a standard deviation of 0.9 °C, but depends slightly on which model is preferred and how much natural variability is allowed. These estimates neglect, however, the fact that carbon dioxide is but one of a number of greenhouse gases and that sulphate aerosols may well have dampened warming. Acknowledging the fact that carbon dioxide is used as a proxy for all human induced changes in radiative forcing brings a lot of additional uncertainty. Prior knowledge on both climate sensitivity and radiative forcing is needed to say anything about the respective sizes. A fully Bayesian approach is used to combine expert knowledge with information from the observations. Prior knowledge on the climate sensitivity plays a dominant role. The data largely exclude climate sensitivity to be small, but cannot exclude climate sensitivity to be large, because of the possibility of strong negative sulphate forcing. The posterior of climate sensitivity has a strong positive skewness. Moreover, its mode (again 3.8 °C; standard deviation 2.4 °C) is higher than the best guess of the IPCC. 相似文献
19.
Review of simulations of climate variability and change with the GFDL R30 coupled climate model 总被引：5，自引：0，他引：5
T. Delworth R. Stouffer K. Dixon M. Spelman T. Knutson A. Broccoli P. Kushner R. Wetherald 《Climate Dynamics》2002,19(7):555-574
A review is presented of the development and simulation characteristics of the most recent version of a global coupled model for climate variability and change studies at the Geophysical Fluid Dynamics Laboratory, as well as a review of the climate change experiments performed with the model. The atmospheric portion of the coupled model uses a spectral technique with rhomboidal 30 truncation, which corresponds to a transform grid with a resolution of approximately 3.75° longitude by 2.25° latitude. The ocean component has a resolution of approximately 1.875° longitude by 2.25° latitude. Relatively simple formulations of river routing, sea ice, and land surface processes are included. Two primary versions of the coupled model are described, differing in their initialization techniques and in the specification of sub-grid scale oceanic mixing of heat and salt. For each model a stable control integration of near millennial scale duration has been conducted, and the characteristics of both the time-mean and variability are described and compared to observations. A review is presented of a suite of climate change experiments conducted with these models using both idealized and realistic estimates of time-varying radiative forcing. Some experiments include estimates of forcing from past changes in volcanic aerosols and solar irradiance. The experiments performed are described, and some of the central findings are highlighted. In particular, the observed increase in global mean surface temperature is largely contained within the spread of simulated global mean temperatures from an ensemble of experiments using observationally-derived estimates of the changes in radiative forcing from increasing greenhouse gases and sulfate aerosols. 相似文献
20.
Attribution of twentieth century temperature change to natural and anthropogenic causes 总被引：6，自引：0，他引：6
P. A. Stott S. F. B. Tett G. S. Jones M. R. Allen W. J. Ingram J. F. B. Mitchell 《Climate Dynamics》2001,17(1):1-21
We analyse possible causes of twentieth century near-surface temperature change. We use an “optimal detection” methodology
to compare seasonal and annual data from the coupled atmosphere-ocean general circulation model HadCM2 with observations averaged
over a range of spatial and temporal scales. The results indicate that the increases in temperature observed in the latter
half of the century have been caused by warming from anthropogenic increases in greenhouse gases offset by cooling from tropospheric
sulfate aerosols rather than natural variability, either internal or externally forced. We also find that greenhouse gases
are likely to have contributed significantly to the warming in the first half of the century. In addition, natural effects
may have contributed to this warming. Assuming one particular reconstruction of total solar irradiance to be correct implies,
when we take the seasonal cycle into account, that solar effects have contributed significantly to the warming observed in
the early part of the century, regardless of any relative error in the amplitudes of the anthropogenic forcings prescribed
in the model. However, this is not the case with an alternative reconstruction of total solar irradiance, based more on the
amplitude than the length of the solar cycle. We also find evidence for volcanic influences on twentieth century near-surface
temperatures. The signature of the eruption of Mount Pinatubo is detected using annual-mean data. We also find evidence for
a volcanic influence on warming in the first half of the century associated with a reduction in mid-century volcanism.
Received: 24 January 2000 / Accepted: 20 April 2000 相似文献