scholarly journals Sensitivity to Glacial Forcing in the CCSM4

2013 ◽  
Vol 26 (6) ◽  
pp. 1901-1925 ◽  
Author(s):  
Esther C. Brady ◽  
Bette L. Otto-Bliesner ◽  
Jennifer E. Kay ◽  
Nan Rosenbloom
Keyword(s):  
Climate Change ◽  
Atmospheric Aerosols ◽  
Radiative Forcing ◽  
Coupled Model ◽  
Meridional Overturning Circulation ◽  
Deep Basin ◽  
Intergovernmental Panel ◽  
Climate System Model ◽  
Orbital Parameters ◽  
Intercomparison Project

Abstract Results are presented from the Community Climate System Model, version 4 (CCSM4), simulation of the Last Glacial Maximum (LGM) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) at the standard 1° resolution, the same resolution as the majority of the CCSM4 CMIP5 long-term simulations for the historical and future projection scenarios. The forcings and boundary conditions for this simulation follow the protocols of the Paleoclimate Modeling Intercomparison Project, version 3 (PMIP3). Two additional CCSM4 CO2 sensitivity simulations, in which the concentrations are abruptly changed at the start of the simulation to the low 185 ppm LGM concentrations (LGMCO2) and to a quadrupling of the preindustrial concentration (4×CO2), are also analyzed. For the full LGM simulation, the estimated equilibrium cooling of the global mean annual surface temperature is 5.5°C with an estimated radiative forcing of −6.2 W m−2. The radiative forcing includes the effects of the reduced LGM greenhouse gases, ice sheets, continental distribution with sea level lowered by approximately 120 m from the present, and orbital parameters, but not changes to atmospheric aerosols or vegetation biogeography. The LGM simulation has an equilibrium climate sensitivity (ECS) of 3.1(±0.3)°C, comparable to the CCSM4 4×CO2 result. The LGMCO2 simulation shows a greater ECS of 4.2°C. Other responses found at the LGM in CCSM4 include a global precipitation rate decrease at a rate of ~2% °C−1, similar to climate change simulations in the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4); a strengthening of the Atlantic meridional overturning circulation (AMOC) with a shoaling of North Atlantic Deep Water and a filling of the deep basin up to sill depth with Antarctic Bottom Water; and an enhanced seasonal cycle accompanied by reduced ENSO variability in the eastern Pacific Ocean’s SSTs.

scholarly journals Pan-spectral observing system simulation experiments of shortwave reflectance and long-wave radiance for climate model evaluation

2015 ◽  
Vol 8 (7) ◽  
pp. 1943-1954 ◽  
Author(s):  
D. R. Feldman ◽  
W. D. Collins ◽  
J. L. Paige
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Coupled Model ◽  
Climate System ◽  
Spectral Measurements ◽  
Intergovernmental Panel ◽  
Climate System Model ◽  
Detection And Attribution ◽  
Long Wave ◽  
Hadley Centre

Abstract. Top-of-atmosphere (TOA) spectrally resolved shortwave reflectances and long-wave radiances describe the response of the Earth's surface and atmosphere to feedback processes and human-induced forcings. In order to evaluate proposed long-duration spectral measurements, we have projected 21st Century changes from the Community Climate System Model (CCSM3.0) conducted for the Intergovernmental Panel on Climate Change (IPCC) A2 Emissions Scenario onto shortwave reflectance spectra from 300 to 2500 nm and long-wave radiance spectra from 2000 to 200 cm−1 at 8 nm and 1 cm−1 resolution, respectively. The radiative transfer calculations have been rigorously validated against published standards and produce complementary signals describing the climate system forcings and feedbacks. Additional demonstration experiments were performed with the Model for Interdisciplinary Research on Climate (MIROC5) and Hadley Centre Global Environment Model version 2 Earth System (HadGEM2-ES) models for the Representative Concentration Pathway 8.5 (RCP8.5) scenario. The calculations contain readily distinguishable signatures of low clouds, snow/ice, aerosols, temperature gradients, and water vapour distributions. The goal of this effort is to understand both how climate change alters reflected solar and emitted infrared spectra of the Earth and determine whether spectral measurements enhance our detection and attribution of climate change. This effort also presents a path forward to understand the characteristics of hyperspectral observational records needed to confront models and inline instrument simulation. Such simulation will enable a diverse set of comparisons between model results from coupled model intercomparisons and existing and proposed satellite instrument measurement systems.

scholarly journals Effects of Ocean Slow Response under Low Warming Targets

2020 ◽  
Vol 33 (2) ◽  
pp. 477-496 ◽  
Author(s):  
Shang-Min Long ◽  
Shang-Ping Xie ◽  
Yan Du ◽  
Qinyu Liu ◽  
Xiao-Tong Zheng ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Coupled Model ◽  
Deep Ocean ◽  
Ocean Warming ◽  
Meridional Overturning Circulation ◽  
Slow Response ◽  
Intercomparison Project ◽  
Meridional Overturning ◽  
Near Future

AbstractThe 2015 Paris Agreement proposed targets to limit global-mean surface temperature (GMST) rise well below 2°C relative to preindustrial level by 2100, requiring a cease in the radiative forcing (RF) increase in the near future. In response to changing RF, the deep ocean responds slowly (ocean slow response), in contrast to the fast ocean mixed layer adjustment. The role of the ocean slow response under low warming targets is investigated using representative concentration pathway (RCP) 2.6 simulations from phase 5 of the Coupled Model Intercomparison Project. In RCP2.6, the deep ocean continues to warm while RF decreases after reaching a peak. The deep ocean warming helps to shape the trajectories of GMST and fuels persistent thermosteric sea level rise. A diagnostic method is used to decompose further changes after the RF peak into a slow warming component under constant peak RF and a cooling component due to the decreasing RF. Specifically, the slow warming component amounts to 0.2°C (0.6°C) by 2100 (2300), raising the hurdle for achieving the low warming targets. When RF declines, the deep ocean warming takes place in all basins but is the most pronounced in the Southern Ocean and Atlantic Ocean where surface heat uptake is the largest. The climatology and change of meridional overturning circulation are both important for the deep ocean warming. To keep the GMST rise at a low level, substantial decrease in RF is required to offset the warming effect from the ocean slow response.

Nexo: água, Clima, Energia e Meio Ambiente - Uma Perspectiva sobre o Empreendimento de Itataia-CE

2020 ◽  
Vol 35 (3) ◽  
pp. 449-457
Author(s):  
Ilma Ribeiro de Lima ◽  
Cleiton da Silva Silveira ◽  
Francisco das Chagas Vasconcelos Júnior
Keyword(s):  
Climate Change ◽  
Coupled Model ◽  
Model Intercomparison ◽  
Intergovernmental Panel ◽  
Intercomparison Project

Resumo A viabilidade hídrica do Complexo Industrial de exploração e beneficiamento de urânio e fosfato em Santa Quitéria - Ceará foi analisada a partir da relação nexo água, energia e clima. Para tanto, foram usadas projeções de precipitação, evapotranspiração e vazão adotanto os modelos globais do Coupled Model Intercomparison Project Phase 5 (CMIP5, utilizados no quinto relatório do Intergovernmental Panel on Climate Change - IPCC-AR5). Dados da matriz energética do Ceará também foram considerados com o intuito de verificar o aumento da demanda energética do estado e a analisar o impacto da sua produção frente aos recursos hídircos. Os modelos divergem quanto ao futuro das precipitações, mas a maioria assinala um aumento da evapotranspiração nos três períodos projetados (2015 - 2044, 2045 - 2074 e 2075 a 2099) nos dois cenários escolhidos (RCP4.5 e RCP8.5) indicando um possível aumento da demanda hídrica para a região.

scholarly journals Contrasts between Urban and Rural Climate in CCSM4 CMIP5 Climate Change Scenarios

2012 ◽  
Vol 25 (5) ◽  
pp. 1390-1412 ◽  
Author(s):  
Keith Oleson
Keyword(s):  
Climate Change ◽  
Rural Areas ◽  
Urban Areas ◽  
Coupled Model ◽  
Climate Change Scenarios ◽  
Climate System Model ◽  
Intercomparison Project ◽  
Urban Heat ◽  
Urban And Rural Areas ◽  
Global Population

A new parameterization of urban areas in the Community Climate System Model version 4 (CCSM4) allows for simulation of temperature in cities where most of the global population lives. CCSM4 Coupled Model Intercomparison Project phase 5 (CMIP5) simulations [Representative Concentration Pathway (RCP) 2.6, 4.5, and 8.5] are analyzed to examine how urban and rural areas might respond differently to changes in climate. The urban heat island (UHI), defined as the urban minus rural air temperature, is used as a metric. The average UHI at the end of the twenty-first century is similar to present day in RCP2.6 and RCP4.5, but decreases in RCP8.5. Both the daytime and nocturnal UHIs decrease in RCP8.5, but the decrease in the daytime UHI is larger and more uniform across regions and seasons than in the nocturnal UHI. This is caused by changes in evaporation that warm the rural surface more than the urban. There is significant spatial and seasonal variability in the response of the nocturnal UHI caused mainly by changes in the rural surface. In Europe, the response to climate change of rural leaf–stem area in summer and clouds and rural soil moisture in winter explains the majority of this variability. Climate change increases the number of warm nights in urban areas substantially more than in rural areas. These results provide evidence that urban and rural areas respond differently to climate change. Thus, the unique aspects of the urban environment should be considered when making climate change projections, particularly since the global population is becoming increasingly urbanized.

scholarly journals Pan-spectral observing system simulation experiments of shortwave reflectance and longwave radiance for climate model evaluation

2014 ◽  
Vol 7 (3) ◽  
pp. 3647-3670
Author(s):  
D. R. Feldman ◽  
W. D. Collins
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Coupled Model ◽  
Measurement Model ◽  
Climate System ◽  
Spectral Measurements ◽  
Intergovernmental Panel ◽  
Climate System Model ◽  
Detection And Attribution ◽  
Spectrally Resolved

Abstract. Top-of-atmosphere spectrally-resolved shortwave reflectances and longwave radiances describe the evolution of the Earth's surface and atmosphere response to feedbacks in and human-induced forcings on the climate system. In order to evaluate proposed long-duration spectral measurements, we have projected 21st century changes described by the Community Climate System Model (CCSM3.0) conducted for the Intergovernmental Panel on Climate Change (IPCC) A2 Emissions Scenario onto shortwave reflectance spectra from 0.3 to 2.5 μm and longwave radiance spectra from 5 to 50 μm at 8 nm and 1 cm−1 resolution, respectively. The radiative transfer calculations have been rigorously validated against published standards and produce complementary signals describing the climate system forcings and feedbacks. Additional demonstration experiments were performed with the MIROC5 and HadGEM2-ES models for the Representative Concentration Pathway 8.5 (RCP8.5) scenario. The calculations contain readily distinguishable signatures of low clouds, snow/ice, aerosols, temperature gradients, and water vapour distributions. The goal of this effort is to understand both how climate change alters the spectrum of the Earth and determine whether spectral measurements enhance our detection and attribution of climate change. This effort also presents a path forward for hyperspectral measurement-model intercomparison by enabling a diverse set of comparisons between model results from coupled model intercomparisons and existing and proposed satellite instrument measurement systems.

scholarly journals The Effects of Younger Dryas Orbital Parameter and Atmospheric pCO<sub>2</sub> Changes on Radiative Forcing and African Monsoonal Circulation

2018 ◽  
Author(s):  
Taylor M. Hughlett ◽  
Arne M. E. Winguth ◽  
Nan Rosenbloom
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
North Atlantic Ocean ◽  
Sediment Cores ◽  
Younger Dryas ◽  
Meridional Overturning Circulation ◽  
Orbital Parameter ◽  
Orbital Parameters ◽  
Climate Change And Variability ◽  
Atmospheric Pco2

Abstract. Differences in the Atlantic meridional overturning circulation (AMOC) from the Younger Dryas (YD) to the Holocene can be explained by, but not limited to, factors relating to atmospheric greenhouse gas concentrations, discharge of freshwater into the surface ocean, and changes in Earth's orbital parameters. Utilizing the Community Earth System Model (CESM1.0.5) with moderate resolution, this study evaluates how Younger Dryas seasonal and annual radiative forcing affect the climate change and variability. The Younger Dryas to Holocene changes in radiative forcing are mostly attributed to change in orbital parameters and to lesser extent to the relatively small rise in atmosphere pCO2, which is supported by a comparison of model simulations with proxy reconstructions of sea surface temperature and oceanic δ18O. These factors led to increased precipitation and reduced transport of water masses in the North Atlantic Ocean. Atmospheric pCO2 and orbital parameter changes are not substantial enough to explain the transition to the Younger Dryas northern hemispheric cooling. Younger Dryas to Holocene changes in the Monsoonal circulation over the African continent appears to be more affected by changes in orbital parameters than in atmospheric pCO2 but underestimated compared to observed reconstructions from ice and sediment cores. Thus, additional mechanisms such as fresh water hosed-cooling and/or ice sheet-albedo effect need to be considered to explain the Younger Dryas to Holocene climate change and variability.

scholarly journals Avaliação de Modelos do CMIP5 que Melhor Expressam a Atuação dos Vórtices Ciclônicos em Altos Níveis (VCANS) no Nordeste Brasileiro (NEB) (Evaluation of the CMIP5 Models that Express the Best Performance of Vortice in High Levels (VCANS) in Northeast...)

2015 ◽  
Vol 7 (5) ◽  
pp. 891
Author(s):  
José Ueliton Pinheiro ◽  
Josemir Araújo Neves ◽  
Rosane Rodrigues Chaves ◽  
David Mendes ◽  
Naurinete Costa Barreto
Keyword(s):  
Climate Change ◽  
Mean Square Error ◽  
Coupled Model ◽  
Mean Square ◽  
Model Intercomparison ◽  
Intergovernmental Panel ◽  
Assessment Report ◽  
Atmospheric Research ◽  
Intercomparison Project ◽  
Environmental Prediction

A pesquisa estudou a saída de modelos de mudanças climáticas que melhor expressam a atuação dos Vórtices Ciclônicos em Altos Níveis (VCANs) no Nordeste Brasileiro (NEB). Os VCANs foram quantificados pela sua ocorrência diária durante 5 anos (1995-1999), no período de outubro a março. O objeto de estudo foram 13 modelos do CMIP5/IPCC/AR5 (Coupled Model Intercomparison Project Phase 5/Intergovernmental Panel on Climate Change/Fifth Assessment Report), comparados com os resultados do NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research), por meio de métodos estatísticos para escolha do modelo que melhor indica a presença dos VCANs no NEB. A primeira análise comparativa foi feita através das correlações de Pearson, Kendall e Spearman, Raiz quadrada do erro quadrático médio, Raiz quadrada do erro quadrático médio normalizada e os índices de Eficiência e desempenho, Nash-Sutcliffe (NSE), Kling-Gupta (KGE) e o Índice de Concordância de Willmott (d). Em seguida foram selecionados os modelos de melhor desempenho e com significância estatística para uma análise posterior de acertos e erros através dos índices: Índice de Proporção Correta (PC), Índice de Sucesso Crítico (ISC), Probabilidade de Detecção (POD), Taxa de alarme Falso (TAF) e Taxa de Tendência (VIÉS). Para os testes estatísticos aplicados na primeira avaliação realizada o modelo MIROC4h foi o que apresentou os melhores índices seguido pelo MIROC-ESM e inmCM4, respectivamente. Além destes, ainda apresentaram correlação estatística significante o MPI-ESM-LR,o MRI-CGCM3 e o CSIRO-MK3-6-0. A segunda análise também apresentou o MIROC4h com os melhores valores de PC, ISC e POD, excetuando-se o VIÉS que apresentou o segundo melhor resultado e o TAF com o pior resultado em relação aos outros 5 modelos. Dessa forma o MIROC4h apresentou-se como o mais indicado entre os modelos do CMIP5 para estudos de cenários presentes e futuros de VCANs no NEB.   A B S T R A C T The research studied the output of climate change models that best express the actions of Upper Tropospheric Cyclonic Vortices (UTCV) in high levels in the Northeast Brazil (NEB). The UTCV were quantified by a daily occurrence for 5 years (1995-1999) in the period from October to March. The object of the study were 13 models from CMIP5/IPCC/AR5 (Coupled Model Intercomparison Project Phase 5 / Intergovernmental Panel on Climate Change / Fifth Assessment Report ), compared with results from the NCEP / NCAR (National Centers for Environmental Prediction / National Center for Atmospheric Research) by means of statistical methods for choosing the model which best indicates the presence of UTCV in the NEB. The first comparative analysis was performed using the Pearson, Spearman and Kendall correlations, mean square error, normalized mean square error and efficiency and performance indices, Nash-Sutcliff (NSE), Kling-Gupta (KGE) and Index of Agreement of the Willmott (d). Then models with better performance and statistical significance for further analysis of successes and mistakes through the indices were selected: Index Proportion Correct (PC), Critical Success Index (CSI), Probability of Detection (POD), False Alarm Rate (FAR) and Trend Rate (BIAS). For the statistical analyzes used in the first test performed MIROC4h model showed the best rates followed by MIROC-ESM and inmCM4 respectively. In addition, further significant statistical correlation MPI-ESM-LR, MRI-CGCM3 and CSIRO-MK3-6-0. The second analysis also showed the MIROC4h with the best values ​​of PC, CSI and POD, except the BIAS that had the second best result and the FAR with the worst result in relation to the other five models considered in this phase. Thus the MIROC4h introduced himself as the most suitable model of the CMIP5 for studies of the present and future scenarios of UTCV in the NEB   

Empfehlungen für die Charakterisierung und Benennung ausgewählter IPCC Klimaszenarien

2021 ◽  
Author(s):  
Frank Kreienkamp ◽  
Barbara Früh ◽  
Sven Kotlarski ◽  
Carsten Linke ◽  
Marc Olefs ◽  
...  
Keyword(s):  
Climate Change ◽  
Coupled Model ◽  
Model Intercomparison ◽  
Intergovernmental Panel ◽  
Representative Concentration Pathways ◽  
Intercomparison Project

&lt;p&gt;Eine zentrale Aufgabe von Klimaforschung und Klimakommunikation ist die Beschreibung m&amp;#246;glicher Entwicklungspfade des k&amp;#252;nftigen Klimas sowie der antreibenden Kr&amp;#228;fte. Diese Entwicklungspfade werden Klimaszenarien genannt. Klimaszenarien wiederum basieren auf Szenarien m&amp;#246;glicher Entwicklung von Gesellschaft, Technologie und Ressourcennutzung, um daraus die resultierenden Emissionen von Treibhausgasen abzusch&amp;#228;tzen.&amp;#160;&lt;/p&gt; &lt;p&gt;In der Nutzerkommunikation werden die Klimaszenarien des Intergovernmental Panel on Climate Change (IPCC) in der Regel mit pr&amp;#228;gnanten Namen beschrieben. Im deutschsprachigen Raum wurden in den letzten Jahren jedoch verschiedene Namen f&amp;#252;r dieselben Klimaszenarien genutzt. Dies f&amp;#252;hrte oft zu Irritationen und Verwechslungen.&lt;/p&gt; &lt;p&gt;Um dem entgegenzuwirken hat nun eine Arbeitsgruppe der drei deutschsprachigen Wetterdienste, Bundes- und Landeseinrichtungen und aus der Klimaforschung erstmals eine Empfehlung f&amp;#252;r eine einheitliche Benennung, Beschreibung und farbliche Kennzeichnung einer Auswahl von Klimaszenarien des IPCC vorgelegt. Dieses betrifft die Szenarien der CMIP6&lt;sup&gt;1&lt;/sup&gt;-Generation die aus zwei sich gegenseitig erg&amp;#228;nzenden Komponenten bestehen: den Shared Socioeconomic Pathways (SSPs) und den Representative Concentration Pathways (RCPs). Im speziellen hier die Szenarien SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0 und SSP5-8.5. Dieses sind die Szenarien die zum einen von den Modellgruppen f&amp;#252;r Modellsimulationen genutzt wurden und oder in der politischen Diskussion regelm&amp;#228;&amp;#223;ig besprochen werden.&lt;/p&gt; &lt;p&gt;Dieser Beitrag stellt die Empfehlungen der Arbeitsgruppe f&amp;#252;r eine einheitliche Sprach- und Kommunikationsregelung &amp;#160;der f&amp;#252;nf derzeit am h&amp;#228;ufigsten genutzten Klimaszenarien im deutschsprachigen Raum vor.&lt;/p&gt; &lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; CMIP6: Coupled Model Intercomparison Project Phase 6&lt;/p&gt;

scholarly journals Incorrect Asian aerosols affecting the attribution and projection of regional climate change in CMIP6 models

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Zhili Wang ◽  
Lei Lin ◽  
Yangyang Xu ◽  
Huizheng Che ◽  
Xiaoye Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Impact Analysis ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern China ◽  
Coupled Model ◽  
Regional Climate Change ◽  
Anthropogenic Aerosol ◽  
Wide Range

AbstractAnthropogenic aerosol (AA) forcing has been shown as a critical driver of climate change over Asia since the mid-20th century. Here we show that almost all Coupled Model Intercomparison Project Phase 6 (CMIP6) models fail to capture the observed dipole pattern of aerosol optical depth (AOD) trends over Asia during 2006–2014, last decade of CMIP6 historical simulation, due to an opposite trend over eastern China compared with observations. The incorrect AOD trend over China is attributed to problematic AA emissions adopted by CMIP6. There are obvious differences in simulated regional aerosol radiative forcing and temperature responses over Asia when using two different emissions inventories (one adopted by CMIP6; the other from Peking university, a more trustworthy inventory) to driving a global aerosol-climate model separately. We further show that some widely adopted CMIP6 pathways (after 2015) also significantly underestimate the more recent decline in AA emissions over China. These flaws may bring about errors to the CMIP6-based regional climate attribution over Asia for the last two decades and projection for the next few decades, previously anticipated to inform a wide range of impact analysis.

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