56 research outputs found
Dataset associated with "Three flavors of radiative feedbacks and their implications for estimating Equilibrium Climate Sensitivity"
No full textThese are numerical data for all plots shown in the paper:
1) The LongRunMIP output of global and annual mean “tas” and “netTOA” for the models CCSM3 (abrupt2x and aburpt4x), CESM (abrupt2x and abrupt4x), CNRMCM61 (abrupt2x and abrupt4x), ECHAM5MPIOM (abrupt4x), GISSE2R (abrupt4x), HadCM3L (abrupt2x and abrupt4x), HadGEM2 (abrupt4x), IPSLCM5A (abrupt4x), MPIESM11 (abrupt4x), MPIESM12 (abrupt2x and abrupt4x)
2) ECSvalues.txt contain the ECS estimates as shown in Fig. 2 in the paper. ECSvalues_Bayesianfit.txt contain the ECS estimate with uncertainty ranges of the energy balance model as presented in Proistosescu et al. 2017.
3) Model output of global and annual mean “tas” and “netTOA” for the model CESM 1.0.4, as shown in Fig. 1. "cesmtempfit*.nc” are the splines fitted to the “tas” output for converting the differential feedback parameter from temperature to time, as detailed in Rugenstein et al. 2016.The realization that atmospheric radiative feedbacks depend on the underlying patterns of surface warming and global temperature, and thus, change over time has led to an ignition of feedback definitions and methods to estimate equilibrium climate sensitivity. We contrast three flavors of radiative feedbacks -- equilibrium, effective, and differential feedback -- and discuss their physical interpretations and applications. We show that their values at any given time can differ more than 1Wm-2K-1 and their implied equilibrium or effective climate sensitivity can differ several degrees. With ten (quasi) equilibrated climate models, we show that 400 years might be enough to estimate the true equilibrium climate sensitivity with a 5% error and a simple regression method utilizing the differential feedback parameter. We argue that a community-wide agreement on the interpretation of the different feedback definitions would advance the quest to narrow the estimate of climate sensitivity
Dataset associated with "El Niño–Southern Oscillation (ENSO) predictability in equilibrated warmer climates"
No full textThe Niño 3.4 index calculated from the LongRunMIP outputs of global and annual TAS in seven models (CCSM3, CESM104, CNRMCM61, GISSE2R, HadCM3L, IPSLCM5A, and MPIESM12) with two forcing levels (control and abrupt4x). The LongRunMIP outputs are gained from an archive described in Rugenstein et al. 2019. All simulations used here are millennial-length long. Predictability.txt and characteristics.txt contain the changes of ENSO characteristics (frequency and events' duration) and ENSO predictability (6-month averaged accuracy). The explained variance of ENSO predictability by ENSO characteristics in the observations, control simulations, and changes between control and abrupt4x simulations.Institute of Oceanography, The Center for Earth System Research and Sustainability, Universität Hamburg, Hamburg, Germany; Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA.Responses of El Niño-Southern Oscillation (ENSO) to global warming remain uncertain, which challenges ENSO forecasts in a warming climate. We investigate changes in ENSO characteristics and predictability in idealized simulations with quadrupled CO2 forcing from seven general circulation models. Comparing the warmer climate to control simulations, ENSO variability weakens, with the neutral state lasts longer, while active ENSO states last shorter and skew to favor the La Niña state. Six-month persistence-assessed ENSO predictability slightly reduces in five models and increases in two models under the warming condition. While the overall changes in ENSO predictability are insignificant, we find significant relationships between changes in predictability and intensity, duration and skewness of the three individual ENSO states. The maximal contribution to changes in the predictability of El Niño, La Niña and neutral states stems from changes in skewness and events' duration. Our findings show that a robust and significant decrease in ENSO characteristics does not imply a similar change in ENSO predictability in a warmer climate. This could be due to model deficiencies in ENSO dynamics and limitations in persistence model when predicting ENSO
Implacement and fluctuations of the Antarctic Ice Sheet across the Eocene-Oligocene transition
No full textBuchbesprechung: Geschichte der Gewerkschaftsbewegung bis '49: Überzeugende Darstellung - weniger geglückte Analyse
No full textKenntnisse über die Geschichte und die jüngste Entwicklung der indonesischen Gewerkschaftsbewegung sind in der europäischen und besonders in der deutschen wissenschaftlichen Literatur nur äußerst selten zu finden. Dieser Mangel wird nun, zumindest was die Geschichte der Gewerkschaften bis zur Unabhängigkeit Indonesiens (1945/49) angeht, durch eine Arbeit behoben, die 1986 der Uni Heidelberg als Dissertation vorgelegt wurde: Eva-Maria Schaarschmidt -Kohl; Die politische Geschichte der indonesischen Gewerkschaftsbewegung bis zur Unabhängigkeit; Köln: Pahl-Rugenstein, 1987 (=Pahl-Rugenstein Hochschulschriften, Gesellschafts- und Naturwissenschaften, 229); IV+143 S
Stable isotope evidence for rapid uplift of the central Apennines since the late Pliocene
No full textThe central Apennines, an accretionary wedge overlying an area of slab detachment, are characterized by prominent topography, active normal faulting, and high uplift rates. However, previous studies have failed to resolve the surface uplift history, complicating efforts to link the topographic evolution with underlying geodynamic processes. We aim to better quantify orographic changes by using stable oxygen isotope paleoaltimetry. Modern surface water δ18O are 5‰ lower at high elevation than at sea level, reflecting orographic rainout over the Apennines. We present 262 new lacustrine and paleosol carbonate δ18O measurements collected from ten extensional intermontane basins—spanning both high and low elevations—and combine these with 1,166 published δ18O data, permitting us to constrain changes in δ18O both spatially and temporally. Since the Pliocene, δ18O in present-day high-elevation basins has continuously decreased, even as δ18O in lowland basins has remained constant over time. We attribute this continuous 5‰ shift to increased orographic rainout as the central Apennines were uplifted. We estimate an increase in mean elevation of approximately 1–2 km since the late Pliocene, and these estimates match the suggested timing and expected amplitude of slab break-off related uplift. This supports the hypothesis that the opening of the Adriatic slab window and associated mantle flow contributed significantly to building topography in the central Apennines. © 2020 Elsevier B.V
Data for: Connecting hemispheric asymmetries of planetary albedo and surface temperature
No full text<p>Satellite measurements show that the Northern and Southern hemispheres reflect equal amounts of short-wave radiation ("albedo symmetry"), but no theory exists on if, how, and why the symmetry is established and maintained. Ambiguously, climate models are strongly biased in albedo symmetry but agree in the sign of the response to CO<sub>2</sub>. We find that mean-state biases in albedo symmetry and surface temperature asymmetry correlate negatively. Similarly, the response of albedo asymmetry to CO<sub>2</sub> forcing correlates negatively with the magnitude of the asymmetry in surface warming. This is true across many and within single climate model simulations: a too warm or stronger warming hemisphere is darker or darkens more than its counterpart. In the 21 years of observations we find the same tendency and hypothesize a) albedo symmetry is a function of the current climate state and b) we will observe an evolution towards albedo asymmetry in coming decades.</p><p>Funding provided by: Science Mission Directorate<br>Crossref Funder Registry ID: http://dx.doi.org/10.13039/100016465<br>Award Number: 80NSSC21K1042</p>
Connecting Hemispheric Asymmetries of Planetary Albedo and Surface Temperature
No full textAbstract Satellite measurements show that the Northern and Southern hemispheres reflect equal amounts of shortwave radiation (“albedo symmetry”), but no theory exists on if, how, and why the symmetry is established and maintained. Ambiguously, climate models are strongly biased in albedo symmetry but agree in the sign of the response to CO2. We find that mean‐state biases in albedo symmetry and hemispheric surface temperature asymmetry correlate negatively. Similarly, the response of albedo asymmetry to CO2 forcing correlates negatively with the magnitude of the asymmetry in surface warming. This is true across many and within single climate model simulations: a too warm or stronger warming hemisphere is darker or darkens more than its counterpart. In the 21 years of observations we find the same tendency and hypothesize (a) albedo symmetry is a function of the current climate state and (b) we will observe an evolution toward albedo asymmetry in coming decades
Surface temperature pattern scenarios suggest larger rates of warming than projected [DATA]
No full textData for global-mean temperature projections and global-mean radiative feedback projections. See PDF for file description
Coupled climate models systematically underestimate radiation response to surface warming
No full textAbstract A realistic representation of top‐of‐the‐atmosphere (TOA) radiation response to surface warming is key for trusting climate model projections. We show that coupled models with freely evolving ocean‐atmosphere interactions systematically underestimate the observed global TOA radiation trend during 2001–2022 in 552 simulations. Locally, even if a simulation spontaneously reproduces observed surface temperature trends, TOA radiation trends are more likely under‐ than overestimated. This response bias stems from the models' inability to reproduce the observed large‐scale surface warming pattern and from errors in the atmospheric physics affecting short‐ and longwave radiation. Models with a better representation of the TOA radiation response to local surface warming have a relatively low equilibrium climate sensitivity. Our bias metric is a novel process‐based approach which links a model's current response to climate change to its behavior in the future
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