研究者詳細 - 野沢　徹

論文 - 野沢　徹

分割表示 67 件中 21 - 40 件目／全件表示 >>

An emission pathway for stabilization at 6 Wm(-2) radiative forcing 査読

Toshihiko Masui, Kenichi Matsumoto, Yasuaki Hijioka, Tsuguki Kinoshita, Toru Nozawa, Sawako Ishiwatari, Etsushi Kato, P. R. Shukla, Yoshiki Yamagata, Mikiko Kainuma

CLIMATIC CHANGE 109 ( 1-2 ) 59 - 76 2011年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Representative Concentration Pathway 6.0 (RCP6) is a pathway that describes trends in long-term, global emissions of greenhouse gases (GHGs), short-lived species, and land-use/land-cover change leading to a stabilisation of radiative forcing at 6.0 Watts per square meter (Wm(-2)) in the year 2100 without exceeding that value in prior years. Simulated with the Asia-Pacific Integrated Model (AIM), GHG emissions of RCP6 peak around 2060 and then decline through the rest of the century. The energy intensity improvement rates changes from 0.9% per year to 1.5% per year around 2060. Emissions are assumed to be reduced cost-effectively in any period through a global market for emissions permits. The exchange of CO2 between the atmosphere and terrestrial ecosystem through photosynthesis and respiration are estimated with the ecosystem model. The regional emissions, except CO2 and N2O, are downscaled to facilitate transfer to climate models.

DOI： 10.1007/s10584-011-0150-5

Estimation of future surface temperature changes constrained using the future‐present correlated modes in inter‐model variability of CMIP3 multimodel simulations 査読

Manabu Abe, Hideo Shiogama, Toru Nozawa, Seita Emori

Journal of Geophysical Research 116 ( D18 ) D18104 2011年9月

Impact of carbonaceous aerosols on precipitation in tropical Africa during the austral summer in the twentieth century 査読

Hiroaki Kawase, Toshihiko Takemura, Toru Nozawa

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 116 2011年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER GEOPHYSICAL UNION

We investigate the impacts of anthropogenic aerosols on a precipitation trend observed over tropical Africa during the austral summer in the twentieth century using an atmosphere-ocean general circulation model (medium-resolution version of the Model for Interdisciplinary Research on Climate (MIROC)). We conducted several numerical experiments forced with various combinations of natural and anthropogenic forcings. These experiments indicate that increased carbonaceous aerosols, especially black carbon (BC) aerosols, have played a vital role in the drying trend over tropical Africa, although increased sulfate aerosols contributed to the drying trend at the northern edge of the Intertropical Convergence Zone over tropical Africa. An analysis using an approximated moisture budget equation indicates that the increased carbonaceous aerosols cause the drying trend through an evaporation reduction and a descending anomaly over tropical Africa. The increases in BC and organic carbon aerosols enhance the absorption and scattering of solar radiation, respectively, resulting in reductions of the incident solar radiation, temperature, and evaporation at the surface. On the other hand, the absorption of solar radiation that is due to BC aerosols causes surrounding atmospheric heating in the lower troposphere, leading to an ascending anomaly over the tropical Atlantic Ocean. The ascending anomaly modulates the zonal atmospheric circulation in the Atlantic Ocean, tropical Africa, and the Indian Ocean, which drives a descending anomaly over tropical Africa. Similar atmospheric heating is observed over tropical Africa by atmospheric soundings during the austral summer in the late twentieth century, which supports our results.

DOI： 10.1029/2011JD015933

Estimation of future surface temperature changes constrained using the future-present correlated modes in inter-model variability of CMIP3 multimodel simulations 査読

Manabu Abe, Hideo Shiogama, Toru Nozawa, Seita Emori

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 116 2011年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER GEOPHYSICAL UNION

This study utilized a new method for future surface temperature changes constrained by model performance in the late 20th century (20C) climate. We applied the singular value decomposition method to investigate covariance between future and present climates in a multimodel ensemble. We established a transfer function between the expansion coefficients of the present and future climate modes. By projecting the observations onto the present modes and using the transfer function, we obtained the best estimates of the future projection. In this study, we extracted the first two significant leading modes. The first mode showed inter-model variation in spatial patterns of temperature change, with Arctic amplification in the future, and the second mode showed variability in temperature change occurring in the southern marginal regions of sea ice in the Arctic for the 20C simulation. Our evaluation suggests that the future warming of the ensemble mean projection underestimated, particularly in the Arctic region. The estimated temperature change depends mainly on the 20C state of the sea ice and surface temperature in the northern North Atlantic Ocean, which are strongly expressed in the first mode of the 20C climate simulation. The leave-one-out cross-validation indicated that our estimation can improve multimodel mean estimates of temperature change in the higher-latitudes of the Northern Hemisphere.

DOI： 10.1029/2010JD015111

Future projections of surface UV‐B in a changing climate 査読

Watanabe Shingo, Sudo K, Nagashima T, Takemura T, Kawase H, Nozawa T

Journal of Geophysical Research: Atmospheres 116 ( D16118 ) 2011年8月

Future changes in tropospheric ozone under Representative Concentration Pathways (RCPs) 査読

Hiroaki Kawase, Tatsuya Nagashima, Kengo Sudo, Toru Nozawa

GEOPHYSICAL RESEARCH LETTERS 38 2011年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER GEOPHYSICAL UNION

We consider future changes in tropospheric ozone based on the Representative Concentration Pathways (RCPs), which are new emission and concentration scenarios for the 5th coupled model intercomparison project. In contrast to the SRES scenarios, all the RCP scenarios assume an emission reduction of NOx by the late 21st Century that has the potential to achieve tropospheric ozone reduction. However, increasing radiative forcing (RF) due to greenhouse gases and changes in CH4 concentration also contribute to differences in the tropospheric ozone distribution among RCP scenarios. In the RCP4.5 and RCP6.0, assuming the stabilization of RF, the increase in tropospheric ozone due to enhanced residual circulation is cancelled out by the ozone reduction due to ozone precursor reductions. In contrast, in the RCP8.5, assuming increasing RF even after 2100, further enhanced residual circulation and significant increase in CH4 cause a dramatic increase in tropospheric ozone. Citation: Kawase, H., T. Nagashima, K. Sudo, and T. Nozawa (2011), Future changes in tropospheric ozone under Representative Concentration Pathways (RCPs), Geophys. Res. Lett., 38, L05801, doi:10.1029/2010GL046402.

DOI： 10.1029/2010GL046402

Observational constraints indicate risk of drying in the Amazon basin 査読

Hideo Shiogama, Seita Emori, Naota Hanasaki, Manabu Abe, Yuji Masutomi, Kiyoshi Takahashi, Toru Nozawa

NATURE COMMUNICATIONS 2 253 2011年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Climate warming due to human activities will be accompanied by hydrological cycle changes. Economies, societies and ecosystems in South America are vulnerable to such water resource changes. Hence, water resource impact assessments for South America, and corresponding adaptation and mitigation policies, have attracted increased attention. However, substantial uncertainties remain in the current water resource assessments that are based on multiple coupled Atmosphere Ocean General Circulation models. This uncertainty varies from significant wetting to catastrophic drying. By applying a statistical method, we characterized the uncertainty and identified global-scale metrics for measuring the reliability of water resource assessments in South America. Here, we show that, although the ensemble mean assessment suggested wetting across most of South America, the observational constraints indicate a higher probability of drying in the Amazon basin. Thus, over-reliance on the consensus of models can lead to inappropriate decision making.

DOI： 10.1038/ncomms1252

Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000 査読

Pardeep Pall, Tolu Aina, Daithi A. Stone, Peter A. Stott, Toru Nozawa, Arno G. J. Hilberts, Dag Lohmann, Myles R. Allen

NATURE 470 ( 7334 ) 382 - 385 2011年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Interest in attributing the risk of damaging weather-related events to anthropogenic climate change is increasing(1). Yet climate models used to study the attribution problem typically do not resolve the weather systems associated with damaging events(2) such as the UK floods of October and November 2000. Occurring during the wettest autumn in England and Wales since records began in 1766(3,4), these floods damaged nearly 10,000 properties across that region, disrupted services severely, and caused insured losses estimated at 1.3 pound billion (refs 5, 6). Although the flooding was deemed a 'wakeup call' to the impacts of climate change at the time(7), such claims are typically supported only by general thermodynamic arguments that suggest increased extreme precipitation under global warming, but fail(8,9) to account fully for the complex hydrometeorology(4,10) associated with flooding. Here we present a multi-step, physically based 'probabilistic event attribution' framework showing that it is very likely that global anthropogenic greenhouse gas emissions substantially increased the risk of flood occurrence in England and Wales in autumn 2000. Using publicly volunteered distributed computing(11,12), we generate several thousand seasonal-forecast-resolution climate model simulations of autumn 2000 weather, both under realistic conditions, and under conditions as they might have been had these greenhouse gas emissions and the resulting large-scale warming never occurred. Results are fed into a precipitation-runoff model that is used to simulate severe daily river runoff events in England and Wales (proxy indicators of flood events). The precise magnitude of the anthropogenic contribution remains uncertain, but in nine out of ten cases our model results indicate that twentieth-century anthropogenic greenhouse gas emissions increased the risk of floods occurring in England and Wales in autumn 2000 by more than 20%, and in two out of three cases by more than 90%.

DOI： 10.1038/nature09762

Impact of the Assimilation of Sea Ice Concentration Data on an Atmosphere-Ocean-Sea Ice Coupled Simulation of the Arctic Ocean Climate 査読

Takahiro Toyoda, Toshiyuki Awaji, Nozomi Sugiura, Shuhei Masuda, Hiromichi Igarashi, Yuji Sasaki, Yoshihisa Hiyoshi, Yoichi Ishikawa, Takashi Mochizuki, Takashi T. Sakamoto, Hiroaki Tatebe, Yoshiki Komuro, Tatsuo Suzuki, Teruyuki Nishimura, Masato Mori, Yoshimitsu Chikamoto, Sayaka Yasunaka, Yukiko Imada, Miki Arai, Masahiro Watanabe, Hideo Shiogama, Toru Nozawa, Akira Hasegawa, Masayoshi Ishii, Masahide Kimoto

SOLA 7 37 - 40 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：METEOROLOGICAL SOC JAPAN

We have investigated the effects of assimilating sea ice concentration (SIC) data on a simulation of Arctic Ocean climate using an atmosphere-ocean-sea ice coupled model. Our results show that the normal overestimation of summertime SIC in the East Siberian Sea and the Beaufort Sea in simulations without sea-ice data input can be greatly reduced by assimilating sea-ice data and that this improvement is also evident in a following hindcast experiment for 3-4 years after the initialization of the assimilation. In the hindcast experiment, enhanced heat storage in both sea ice and in the ocean surface layer plays a central role in improving the accuracy of the sea ice distribution, particularly in summer. Our detailed investigation suggests that the ice-albedo feedback and the feedback associated with the atmospheric pressure pattern generated by the improved estimation of SIC work more effectively to retain the heat signal after initialization for a coupled atmosphere-ocean-sea ice system prediction. In addition, comparison with field observations confirms that the model fails to produce a realistic feedback loop, which is (presumably) due to inadequacies in both the ice-cloud feedback model and the feedback via the Beaufort Gyre circulation. Further development of coupled models is thus required to better define Arctic Ocean climate processes and to improve the accuracy of their predictions.

DOI： 10.2151/sola.2011-010

MIROC-ESM 2010: Model description and basic results of CMIP5-20c3m experiments 査読

S. Watanabe, T. Hajima, K. Sudo, T. Nagashima, T. Takemura, H. Okajima, T. Nozawa, H. Kawase, M. Abe, T. Yokohata, T. Ise, H. Sato, E. Kato, K. Takata, S. Emori, M. Kawamiya

Geoscientific Model Development 4 ( 4 ) 845 - 872 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Copernicus GmbH

An earth system model (MIROC-ESM 2010) is fully described in terms of each model component and their interactions. Results for the CMIP5 (Coupled Model Intercomparison Project phase 5) historical simulation are presented to demonstrate the model's performance from several perspectives: atmosphere, ocean, sea-ice, land-surface, ocean and terrestrial biogeochemistry, and atmospheric chemistry and aerosols. An atmospheric chemistry coupled version of MIROC-ESM (MIROC-ESM-CHEM 2010) reasonably reproduces transient variations in surface air temperatures for the period 1850-2005, as well as the present-day climatology for the zonal-mean zonal winds and temperatures from the surface to the mesosphere. The historical evolution and global distribution of column ozone and the amount of tropospheric aerosols are reasonably simulated in the model based on the Representative Concentration Pathways' (RCP) historical emissions of these precursors. The simulated distributions of the terrestrial and marine biogeochemistry parameters agree with recent observations, which is encouraging to use the model for future global change projections. © 2011 Author(s).

DOI： 10.5194/gmd-4-845-2011

Impact of carbonaceous aerosols on precipitation in tropical Africa during the austral summer in the 20th Century 査読

Kawase, H, T. Takemura, T. Nozawa

Journal of Geophysical Research 116 ( D18 ) D18116 2011年

Improved Climate Simulation by MIROC5. Mean States, Variability, and Climate Sensitivity 査読

Masahiro Watanabe, Tatsuo Suzuki, Ryouta O'ishi, Yoshiki Komuro, Shingo Watanabe, Seita Emori, Toshihiko Takemura, Minoru Chikira, Tomoo Ogura, Miho Sekiguchi, Kumiko Takata, Dai Yamazaki, Tokuta Yokohata, Toru Nozawa, Hiroyasu Hasumi, Hiroaki Tatebe, Masahide Kimoto

JOURNAL OF CLIMATE 23 ( 23 ) 6312 - 6335 2010年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER METEOROLOGICAL SOC

A new version of the atmosphere ocean general circulation model cooperatively produced by the Japanese research community known as the Model for Interdisciplinary Research on Climate (MIROC) has recently been developed A century long control experiment was performed using the new version (MIROC5) with the standard resolution of the T85 atmosphere and 1 degrees ocean models The climatological mean state and variability are then compared with observations and those in a previous version (MIROC3 2) with two different resolutions (medres hires) coarser and finer than the resolution of MIROC5A few aspects of the mean fields in MIROC5 are similar to or slightly worse than MIROC3 2 but otherwise the climatological features are considerably better In particular improvements are found in precipitation zonal mean atmospheric fields equatorial ocean subsurface fields and the simulation of El Nino-Southern Oscillation The difference between MIROC5 and the previous model is larger than that between the two MIROC3 2 versions indicating a greater effect of updating parameterization schemes on the model climate than increasing the model resolution The mean cloud property obtained from the sophisticated prognostic schemes in MIROC5 shows good agreement with satellite measurements MIROC5 reveals an equilibrium climate sensitivity of 2 6 K which is lower than that in MIROC3 2 by 1 K This is probably due to the negative feedback of low clouds to the increasing concentration of CO2 which is opposite to that in MIROC3 2

DOI： 10.1175/2010JCLI3679.1

Physical mechanism of long-term drying trend over tropical North Africa (vol 37, L21706, 2010) 査読

Hiroaki Kawase, Manabu Abe, Yukiko Yamada, Toshihiko Takemura, Tokuta Yokohata, Toru Nozawa

GEOPHYSICAL RESEARCH LETTERS 37 2010年11月

Probabilistic estimates of recent changes in temperature: a multi-scale attribution analysis 査読

Nikolaos Christidis, Peter A. Stott, Francis W. Zwiers, Hideo Shiogama, Toru Nozawa

CLIMATE DYNAMICS 34 ( 7-8 ) 1139 - 1156 2010年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

The role of anthropogenic forcings in temperature changes during recent decades is investigated over a range of spatial scales. Changes in the annual mean surface temperature and also in the warmest night of the year, which has implications for human health, are considered. Distributions of regional trends with and without the effect of human activity are produced, using constraints from a global optimal detection analysis. Anthropogenic forcings are estimated to have more than doubled the likelihood of mean warming in all regions considered except central North America, where results are more model dependent. The likelihood of warming of the warmest night has also increased, but the estimated change is more uncertain. Inferences on sub-continental scales are indicative rather than definitive because of the absence of locally important forcings and processes in model simulations, as well as model biases. As model inconsistencies may impact regional analyses, a multi-model approach is essential.

DOI： 10.1007/s00382-009-0615-7

Emission Scenario Dependency of Precipitation on Global Warming in the MIROC3.2 Model 査読

Hideo Shiogama, Seita Emori, Kiyoshi Takahashi, Tatsuya Nagashima, Tomoo Ogura, Toru Nozawa, Toshihiko Takemura

JOURNAL OF CLIMATE 23 ( 9 ) 2404 - 2417 2010年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER METEOROLOGICAL SOC

The precipitation sensitivity per 1 K of global warming in twenty-first-century climate projections is smaller in an emission scenario with larger greenhouse gas concentrations and aerosol emissions, according to the Model for Interdisciplinary Research on Climate 3.2 (MIROC3.2) coupled atmosphere-ocean general circulation model. The authors examined the reasons for the precipitation sensitivity to emission scenarios by performing separated individual forcing runs under high and low emission scenarios. It was found that the dependency on emission scenario is mainly caused by differences in black and organic carbon aerosol forcing (the sum of which is cooling forcing) between the emission scenarios and that the precipitation is more sensitive to carbon aerosols than well-mixed greenhouse gases. They also investigated the reason for the larger precipitation sensitivity (larger magnitude of precipitation decrease per 1 K cooling of temperature) in the carbon aerosol runs. Surface dimming due to the direct and indirect effects of carbon aerosols effectively decreases evaporation and precipitation, which enhances the precipitation sensitivity in the carbon aerosol runs. In terms of the atmospheric moisture cycle, although changes of vertical circulation offset the effects of changes in the atmospheric moisture in both the carbon aerosol and greenhouse gas runs, the amplitude of vertical circulation change per 1 K temperature change is less in the carbon aerosol runs. Furthermore, the second indirect effect of organic carbon aerosol counteracts the influence of the vertical circulation change. These factors lead to suppression of changes in the moisture's atmospheric residence time and increase of the precipitation sensitivity in the carbon aerosol runs.

DOI： 10.1175/2009JCLI3428.1

Physical mechanism of long-term drying trend over tropical North Africa 査読

Hiroaki Kawase, Manabu Abe, Yukiko Yamada, Toshihiko Takemura, Tokuta Yokohata, Toru Nozawa

GEOPHYSICAL RESEARCH LETTERS 37 2010年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER GEOPHYSICAL UNION

Based on an approximated moisture budget equation, we investigate the physical mechanisms of a drying trend observed over tropical North Africa in the boreal summer during the 20th Century by analyzing datasets of several climate-model experiments forced with various combinations of natural and anthropogenic forcings. Increased anthropogenic aerosols thermodynamically induce a drying trend due to a tropospheric cooling and dynamically induce an additional drying trend due to an atmospheric local circulation change stirred up by the strong gradient of a sea surface temperature anomaly over the tropical Atlantic Ocean. Increased greenhouse gases, on the other hand, induce a drying trend through the large-scale dynamic effect, which is canceled out by the thermodynamically induced moistening trend due to tropospheric warming. Therefore, the drying trend observed over tropical North Africa during the 20th Century is strongly affected by the increased anthropogenic aerosols through both the dynamic and thermodynamic effects. Citation: Kawase, H., M. Abe, Y. Yamada, T. Takemura, T. Yokohata, and T. Nozawa (2010), Physical mechanism of long term drying trend over tropical North Africa, Geophys. Res. Lett., 37, L09706, doi: 10.1029/2010GL043038.

DOI： 10.1029/2010GL043038

Emission scenario dependencies in climate change assessments of the hydrological cycle 査読

Hideo Shiogama, Naota Hanasaki, Yuji Masutomi, Tatsuya Nagashima, Tomoo Ogura, Kiyoshi Takahashi, Yasuaki Hijioka, Toshihiko Takemura, Toru Nozawa, Seita Emori

CLIMATIC CHANGE 99 ( 1-2 ) 321 - 329 2010年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Anthropogenic global warming will lead to changes in the global hydrological cycle. The uncertainty in precipitation sensitivity per 1 K of global warming across coupled atmosphere-ocean general circulation models (AOGCMs) has been actively examined. On the other hand, the uncertainty in precipitation sensitivity in different emission scenarios of greenhouse gases (GHGs) and aerosols has received little attention. Here we show a robust emission-scenario dependency (ESD); smaller global precipitation sensitivities occur in higher GHG and aerosol emission scenarios. Although previous studies have applied this ESD to the multi-AOGCM mean, our surprising finding is that current AOGCMs all have the common ESD in the same direction. Different aerosol emissions lead to this ESD. The implications of the ESD of precipitation sensitivity extend far beyond climate analyses. As we show, the ESD potentially propagates into considerable biases in impact assessments of the hydrological cycle via a widely used technique, so-called pattern scaling. Since pattern scaling is essential to conducting parallel analyses across climate, impact, adaptation and mitigation scenarios in the next report from the Intergovernmental Panel on Climate Change, more attention should be paid to the ESD of precipitation sensitivity.

DOI： 10.1007/s10584-009-9765-1

Pacific decadal oscillation hindcasts relevant to near-term climate prediction 査読

Takashi Mochizuki, Masayoshi Ishii, Masahide Kimoto, Yoshimitsu Chikamoto, Masahiro Watanabe, Toru Nozawa, Takashi T. Sakamoto, Hideo Shiogama, Toshiyuki Awaji, Nozomi Sugiura, Takahiro Toyoda, Sayaka Yasunaka, Hiroaki Tatebe, Masato Mori

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 107 ( 5 ) 1833 - 1837 2010年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATL ACAD SCIENCES

Decadal-scale climate variations over the Pacific Ocean and its surroundings are strongly related to the so-called Pacific decadal oscillation (PDO) which is coherent with wintertime climate over North America and Asian monsoon, and have important impacts on marine ecosystems and fisheries. In a near-term climate prediction covering the period up to 2030, we require knowledge of the future state of internal variations in the climate system such as the PDO as well as the global warming signal. We perform sets of ensemble hindcast and forecast experiments using a coupled atmosphere-ocean climate model to examine the predictability of internal variations on decadal timescales, in addition to the response to external forcing due to changes in concentrations of greenhouse gases and aerosols, volcanic activity, and solar cycle variations. Our results highlight that an initialization of the upper-ocean state using historical observations is effective for successful hindcasts of the PDO and has a great impact on future predictions. Ensemble hindcasts for the 20th century demonstrate a predictive skill in the upper-ocean temperature over almost a decade, particularly around the Kuroshio-Oyashio extension (KOE) and subtropical oceanic frontal regions where the PDO signals are observed strongest. A negative tendency of the predicted PDO phase in the coming decade will enhance the rising trend in surface air-temperature (SAT) over east Asia and over the KOE region, and suppress it along the west coasts of North and South America and over the equatorial Pacific. This suppression will contribute to a slowing down of the global-mean SAT rise.

DOI： 10.1073/pnas.0906531107

Possible Influence of Volcanic Activity on the Decadal Potential Predictability of the Natural Variability in Near-Term Climate Predictions 査読

Hideo Shiogama, Seita Emori, Takashi Mochizuki, Sayaka Yasunaka, Tokuta Yokohata, Masayoshi Ishii, Toru Nozawa, Masahide Kimoto

ADVANCES IN METEOROLOGY 2010 2010年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：HINDAWI LTD

Initialization based on data assimilations using historical observations possibly improves near-term climate predictions. Significant volcanic activity in the future is unpredictable and not assumed in future climate predictions. To examine the possible influence of unpredictable future volcanic activity on the decadal potential predictability of the natural variability, we performed a 2006-2035 climate prediction experiment with the assumption that the 1991 Mt. Pinatubo eruption would take place again in 2010. The Pinatubo forcing induced not only significant cooling responses but also considerable noises in the natural variability. The errors due to the Pinatubo forcing grew faster than that arising from imperfect knowledge of the observed state, leading to a rapid reduction of the decadal potential predictability of the natural variability.

DOI： 10.1155/2010/657318

Correlation between Inter-Model Similarities in Spatial Pattern for Present and Projected Future Mean Climate 査読

Manabu Abe, Hideo Shiogama, Julia C. Hargreaves, James D. Annan, Toru Nozawa, Seita Emori

SOLA 5 133 - 136 2009年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：METEOROLOGICAL SOC JAPAN

When an averaging method is used for model future projection with weights determined according to the model performance in the present climate, generally, the stationarity of the model performance between present and future is implicitly assumed. Here we investigate this assumption using multi-model data. We consider the correlation between inter-model similarities in the spatial pattern for the present-day climate and future climate change for surface air temperature, precipitation and sea level pressure on global and zonal domains in the seasonal time scale. We further extend previous work by devising a bootstrap method to estimate the statistical significance of all correlations, which have previously not been estimated. Most of the correlation coefficients for precipitation were significant, but moderate or low in the absolute value. Many of those for the other variables were not significant. Also, we discuss the magnitude of the inter-model similarity used in this work.

DOI： 10.2151/sola.2009-034

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