El Niño and Greenhouse Warming: Results from Ensemble Simulations with the NCAR CCSM

2005 ◽  
Vol 18 (22) ◽  
pp. 4669-4683 ◽  
Author(s):  
Hein Zelle ◽  
Geert Jan van Oldenborgh ◽  
Gerrit Burgers ◽  
Henk Dijkstra
Keyword(s):  
Response Pattern ◽  
Climate System ◽  
Intergovernmental Panel ◽  
Climate System Model ◽  
Ensemble Simulations ◽  
System A ◽  
Global Mean Surface Temperature ◽  
Wind Response ◽  
Business As Usual ◽  
Global Mean

Abstract The changes in model ENSO behavior due to an increase in greenhouse gases, according to the Intergovernmental Panel on Climate Change (IPCC) Business-As-Usual scenario, are investigated using a 62-member ensemble 140-yr simulation (1940–2080) with the National Center for Atmospheric Research Community Climate System Model (CCSM; version 1.4). Although the global mean surface temperature increases by about 1.2 K over the period 2000–80, there are no significant changes in the ENSO period, amplitude, and spatial patterns. To explain this behavior, an analysis of the simulation results is combined with results from intermediate complexity coupled ocean–atmosphere models. It is shown that this version of the CCSM is incapable of simulating a correct meridional extension of the equatorial wind stress response to equatorial SST anomalies. The wind response pattern is too narrow and its strength is insensitive to background SST. This leads to a more stable Pacific climate system, a shorter ENSO period, and a reduced sensitivity of ENSO to global warming.

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 On the Usage of Spectral and Broadband Satellite Instrument Measurements to Differentiate Climate Models with Different Cloud Feedback Strengths

2013 ◽  
Vol 26 (17) ◽  
pp. 6561-6574 ◽  
Author(s):  
Daniel R. Feldman ◽  
Daniel M. Coleman ◽  
William D. Collins
Keyword(s):  
Near Infrared ◽  
Climate Models ◽  
Longwave Radiation ◽  
Cloud Feedback ◽  
Climate System ◽  
Spectral Radiance ◽  
Intergovernmental Panel ◽  
Climate System Model ◽  
Cloud Feedbacks ◽  
The Difference

Abstract Top-of-atmosphere radiometric signals associated with different high- and low-cloud–radiative feedbacks have been examined through the use of an observing system simulation experiment (OSSE). The OSSE simulates variations in the spectrally resolved and spectrally integrated signals that are due to a range of plausible feedbacks of the climate system when forced with CO2 concentrations that increase at 1% yr−1. This initial version of the OSSE is based on the Community Climate System Model, version 3 (CCSM3), and exploits the fact that CCSM3 exhibits different cloud feedback strengths for different model horizontal resolutions. In addition to the conventional broadband shortwave albedos and outgoing longwave fluxes, a dataset of shortwave spectral reflectance and longwave spectral radiance has been created. These data have been analyzed to determine simulated satellite instrument signals of poorly constrained cloud feedbacks for three plausible realizations of Earth's climate system produced by CCSM3. These data have been analyzed to estimate the observational record length of albedo, outgoing longwave radiation, shortwave reflectance, or longwave radiance required to differentiate these dissimilar Earth system realizations. Shortwave spectral measurements in visible and near-infrared water vapor overtone lines are best suited to differentiate model results, and a 33% difference in shortwave–cloud feedbacks can be detected with 20 years of continuous measurements. Nevertheless, at most latitudes and with most wavelengths, the difference detection time is more than 30 years. This suggests that observing systems of sufficiently stable calibration would be useful in addressing the contribution of low clouds to the spread of climate sensitivities currently exhibited by the models that report to the Intergovernmental Panel on Climate Change (IPCC).

scholarly journals A future perspective of historical contributions to climate change

2021 ◽  
Vol 164 (1-2) ◽  
Author(s):  
Ragnhild B. Skeie ◽  
Glen P. Peters ◽  
Jan Fuglestvedt ◽  
Robbie Andrew
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Integrated Assessment ◽  
Climate System ◽  
Future Perspective ◽  
Integrated Assessment Models ◽  
Geographical Regions ◽  
Global Mean Surface Temperature ◽  
Global Mean ◽  
Future Emissions

AbstractCountries’ historical contributions to climate change have been on the agenda for more than two decades and will most likely continue to be an element in future international discussions and negotiations on climate. Previous studies have quantified the historical contributions to climate change across a range of choices and assumptions. In contrast, we quantify how historical contributions to changes in global mean surface temperature (GMST) may change in the future for a broad set of choices using the quantification of the shared socioeconomic pathways (SSPs). We calculate the contributions for five coarse geographical regions used in the SSPs. Historical emissions of long-lived gases remain important for future contributions to warming, due to their accumulation and the inertia of climate system, and historical emissions are even more important for strong mitigation scenarios. When only accounting for future emissions, from 2015 to 2100, there is surprisingly little variation in the regional contributions to GMST change between the different SSPs and different mitigation targets. The largest variability in the regional future contributions is found across the different integrated assessment models (IAMs). This suggests the characteristics of the IAMs are more important for calculated future historical contributions than variations across SSP or forcing target.

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 Estimating the Effect of Radiative Feedback Uncertainties on Climate Response to Changes in the Concentration of Stratospheric Aerosols

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 654
Author(s):  
Sergei Soldatenko
Keyword(s):  
Surface Temperature ◽  
Radiative Forcing ◽  
Deep Ocean ◽  
Climate System ◽  
Ocean Heat Uptake ◽  
Heat Uptake ◽  
Global Mean Surface Temperature ◽  
Radiative Feedbacks ◽  
Global Mean ◽  
System Inertia

Using the two-box energy balance model (EBM), we explore the climate system response to radiative forcing generated by variations in the concentrations of stratospheric aerosols and estimate the effect of uncertainties in radiative feedbacks on changes in global mean surface temperature anomaly used as an indicator of the response of the climate system to external radiative perturbations. Radiative forcing generated by stratospheric sulfate aerosols from the second-largest volcanic eruption in the 20th century, the Mount Pinatubo eruption in June 1991, was chosen for this research. The global mean surface temperature response to a specified change in radiative forcing is estimated as a convolution of the derived impulse response function corresponding to EBM with a function that describes the temporal change in radiative forcing. The influence of radiative feedback uncertainties on changes in the global mean surface temperature is estimated using several “versions” of the EBM. The parameters for different “versions” were identified by applying a specific procedure for calibrating the two-box EBM parameters using the results of climate change simulations conducted with coupled atmosphere–ocean general circulation models from the Coupled Model Intercomparison Project phase 5 (CMIP5). Changes in the global mean surface temperature caused by stratospheric aerosol forcing are found to be highly sensitive not only to radiative feedbacks but also to climate system inertia defined by the effective heat capacity of the atmosphere–land–ocean mixed layer system, as well as to deep-ocean heat uptake. The results obtained have direct implications for a better understanding of how uncertainties in climate feedbacks, climate system inertia and deep-ocean heat uptake affect climate change modelling.

scholarly journals Global warming projection using NCAR Climate System Model (CSM)

1998 ◽  
Vol 6 ◽  
pp. 187-192
Author(s):  
Hiromaru HIRAKUCHI ◽  
Kohki MARUYAMA ◽  
Jun'ichi TSUTSUI ◽  
Norikazu NAKASHIKI
Keyword(s):  
Global Warming ◽  
Climate System ◽  
System Model ◽  
Climate System Model ◽  
Global Warming Projection

Systematic exploration of scenario spaces

foresight ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 59-75 ◽  
Author(s):  
Henrik Carlsen ◽  
E. Anders Eriksson ◽  
Karl Henrik Dreborg ◽  
Bengt Johansson ◽  
Örjan Bodin
Keyword(s):  
Climate Change ◽  
Methodological Approach ◽  
Intergovernmental Panel ◽  
Climate Change Research ◽  
Content Type ◽  
Generating Sets ◽  
Ex Post ◽  
Systematic Exploration ◽  
Emissions Scenarios ◽  
Business As Usual

Purpose – Scenarios have become a vital methodological approach in business as well as in public policy. When scenarios are used to guide analysis and decision-making, the aim is typically robustness and in this context we argue that two main problems at scenario set level is conservatism, i.e. all scenarios are close to a perceived business-as-usual trajectory and lack of balance in the sense of arbitrarily mixing some conservative and some extreme scenarios. The purpose of this paper is to address these shortcomings by proposing a methodology for generating sets of scenarios which are in a mathematical sense maximally diverse. Design/methodology/approach – In this paper, we develop a systematic methodology, Scenario Diversity Analysis (SDA), which addresses the problems of broad span vs conservatism and imbalance. From a given set of variables with associated states, SDA generates scenario sets where the scenarios are in a quantifiable sense maximally different and therefore best span the whole set of feasible scenarios. Findings – The usefulness of the methodology is exemplified by applying it to sets of storylines of the emissions scenarios of the Intergovernmental Panel on Climate Change. This ex-post analysis shows that the storylines were not maximally diverse and given the challenges ahead with regard to emissions reduction and adaptation planning, we argue that it is important to strive for diversity when developing scenario sets for climate change research. Originality/value – The proposed methodology adds significant novel features to the field of systematic scenario generation, especially with regard to scenario diversity. The methodology also enables the combination of systematics with the distinct future logics of good intuitive logics scenarios.

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