scholarly journals A timescale analysis of the NH temperature response to volcanic and solar forcing in the past millenium

2005 ◽  
Vol 1 (2) ◽  
pp. 137-153 ◽  
Author(s):  
S. L. Weber
Keyword(s):  
Climate Model ◽  
Temperature Response ◽  
Volcanic Eruptions ◽  
Time Interval ◽  
Solar Forcing ◽  
Model Driven ◽  
Reconstructed Temperature ◽  
Volcanic Forcing ◽  
Temperature Records ◽  
Recent Claim

Abstract. The Northern Hemisphere temperature response to volcanic and solar forcing is studied using first a set of simulations with an intermediate-complexity climate model, driven by reconstructed forcings. Results are than compared with those obtained from the seven high-resolution reconstructed temperature records for the last millenium that are at present available. Focus of the analysis is on the timescale dependence of the response. Results between the model and the proxy-based reconstructions are remarkably consistent. The response to solar forcing is found to equilibrate at interdecadal timescales, reaching an equilibrium value for the regression of 0.2-0.3°C per W/m2. The time interval between volcanic eruptions is typically shorter than the dissipation timescale of the climate system, so that the response to volcanic forcing never equilibrates. As a result, the regression on the volcanic forcing is always lower than the equilibrium value and goes to zero for the longest temporal scales. The trends over the pre-anthropogenic period are found to be relatively large in all reconstructed temperature records compared to their interdecadal-centennial variability. This is at variance with a recent claim that reconstructed temperature records underestimate climatic variations at multi-centennial scales.

scholarly journals A timescale analysis of the Northern Hemisphere temperature response to volcanic and solar forcing

2005 ◽  
Vol 1 (1) ◽  
pp. 9-17 ◽  
Author(s):  
S. L. Weber
Keyword(s):  
Northern Hemisphere ◽  
Temperature Response ◽  
Volcanic Eruptions ◽  
Time Interval ◽  
Solar Forcing ◽  
Northern Hemisphere Temperature ◽  
Reconstructed Temperature ◽  
Volcanic Forcing ◽  
Hemisphere Temperature ◽  
Temperature Records

Abstract. The Northern Hemisphere temperature response to volcanic and solar forcing in the time interval 1000–1850 AD is studied using first a set of simulations with an intermediate-complexity climate model, driven by reconstructed forcings. Results are then compared with those obtained from the seven high-resolution reconstructed temperature records for the last millenium that are at present available. Focus of the analysis is on the timescale dependence of the response. Results between the model and the proxy-based reconstructions are remarkably consistent. The response to solar forcing is found to equilibrate at interdecadal timescales, reaching an equilibrium value for the regression of 0.2–0.3°C per W/m2. The time interval between volcanic eruptions is typically shorter than the dissipation timescale of the climate system, so that the response to volcanic forcing never equilibrates. As a result, the regression on the volcanic forcing is always lower than the equilibrium value and goes to zero for the longest temporal scales. The trends over the pre-anthropogenic period are found to be relatively large in all reconstructed temperature records, given the trends in the reconstructed forcing and the equilibrium value for the regression. This is at variance with a recent claim that reconstructed temperature records underestimate climatic variations at multi-centennial timescales.

scholarly journals The Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP): Experimental design and forcing input data

2016 ◽  
Author(s):  
Davide Zanchettin ◽  
Myriam Khodri ◽  
Claudia Timmreck ◽  
Matthew Toohey ◽  
Anja Schmidt ◽  
...  
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Initial Conditions ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Model Intercomparison ◽  
Climatic Response ◽  
Volcanic Forcing ◽  
Intercomparison Project

Abstract. The enhancement of the stratospheric aerosol layer by volcanic eruptions induces a complex set of responses causing global and regional climate effects on a broad range of timescales. Uncertainties exist regarding the climatic response to strong volcanic forcing identified in coupled climate simulations that contributed to the fifth phase of the Climate Model Intercomparison Project (CMIP5). In order to better understand the sources of these model diversities, the model intercomparison project on the climate response to volcanic forcing (VolMIP) has defined a coordinated set of idealized volcanic perturbation experiments to be carried out in alignment with the CMIP6 protocol. VolMIP provides a common stratospheric aerosol dataset for each experiment to eliminate differences in the applied volcanic forcing, and defines a set of initial conditions to determine how internal climate variability contributes to determining the response. VolMIP will assess to what extent volcanically-forced responses of the coupled ocean-atmosphere system are robustly simulated by state-of-the-art coupled climate models and identify the causes that limit robust simulated behavior, especially differences in the treatment of physical processes. This paper illustrates the design of the idealized volcanic perturbation experiments in the VolMIP protocol and describes the common aerosol forcing input datasets to be used.

Volcanic forcing of climate since 1850 in an interactive aerosol-chemistry-climate model

2021 ◽  
Author(s):  
Thomas Aubry ◽  
Anja Schmidt ◽  
Alix Harrow ◽  
Jeremy Walton ◽  
Jane Mulcahy ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Coupled Model ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Aerosol Model ◽  
Volcanic Forcing

<p>Reconstructions of volcanic aerosol forcing and its climatic impacts are undermined by uncertainties in both the models used to build these reconstructions as well as the proxy and observational records used to constrain those models. Reducing these uncertainties has been a priority and in particular, several modelling groups have developed interactive stratospheric aerosol models. Provided with an initial volcanic injection of sulfur dioxide, these models can interactively simulate the life cycle and optical properties of sulfate aerosols, and their effects on climate. In contrast, most climate models that took part in the Coupled Model Intercomparison Project Phase 5 and 6 (CMIP6) directly prescribe perturbations in atmospheric optical properties associated with an eruption. However, before the satellite era, the volcanic forcing dataset used for CMIP6 mostly relies on a relatively simple aerosol model and a volcanic sulfur inventory derived from ice-cores, both of which have substantial associated uncertainties.</p><p>In this study, we produced a new set of historical simulations using the UK Earth System Model UKESM1, with interactive stratospheric aerosol capability (referred to as interactive runs hereafter) instead of directly prescribing the CMIP6 volcanic forcing dataset as was done for CMIP6 (standard runs, hereafter). We used one of the most recent volcanic sulfur inventories as input for the interactive runs, in which aerosol properties are consistent with the model chemistry, microphysics and atmospheric components. We analyzed how the stratospheric aerosol optical depth, the radiative forcing and the climate response to volcanic eruptions differed between interactive and standard runs, and how these compare to observations and proxy records. In particular, we investigate in detail the differences in the response to the large-magnitude Krakatoa 1883 eruption between the two sets of runs. We also discuss differences for the 1979-2015 period where the forcing data in standard runs is directly constrained from satellite observations. Our results shed new light on uncertainties affecting the reconstruction of past volcanic forcing and highlight some of the benefits and disadvantages of using interactive stratospheric aerosol capabilities instead of a unique prescribed volcanic forcing dataset in CMIP’s historical runs.</p>

scholarly journals Volcanic forcing for climate modeling: a new microphysics-based data set covering years 1600–present

2014 ◽  
Vol 10 (1) ◽  
pp. 359-375 ◽  
Author(s):  
F. Arfeuille ◽  
D. Weisenstein ◽  
H. Mack ◽  
E. Rozanov ◽  
T. Peter ◽  
...  
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
Circulation Model ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Global Scale ◽  
Stratospheric Aerosol ◽  
Set Covering ◽  
Data Set ◽  
Volcanic Forcing

Abstract. As the understanding and representation of the impacts of volcanic eruptions on climate have improved in the last decades, uncertainties in the stratospheric aerosol forcing from large eruptions are now linked not only to visible optical depth estimates on a global scale but also to details on the size, latitude and altitude distributions of the stratospheric aerosols. Based on our understanding of these uncertainties, we propose a new model-based approach to generating a volcanic forcing for general circulation model (GCM) and chemistry–climate model (CCM) simulations. This new volcanic forcing, covering the 1600–present period, uses an aerosol microphysical model to provide a realistic, physically consistent treatment of the stratospheric sulfate aerosols. Twenty-six eruptions were modeled individually using the latest available ice cores aerosol mass estimates and historical data on the latitude and date of eruptions. The evolution of aerosol spatial and size distribution after the sulfur dioxide discharge are hence characterized for each volcanic eruption. Large variations are seen in hemispheric partitioning and size distributions in relation to location/date of eruptions and injected SO2 masses. Results for recent eruptions show reasonable agreement with observations. By providing these new estimates of spatial distributions of shortwave and long-wave radiative perturbations, this volcanic forcing may help to better constrain the climate model responses to volcanic eruptions in the 1600–present period. The final data set consists of 3-D values (with constant longitude) of spectrally resolved extinction coefficients, single scattering albedos and asymmetry factors calculated for different wavelength bands upon request. Surface area densities for heterogeneous chemistry are also provided.

Diagnosis of Radiosonde Vertical Temperature Trend Profiles: Comparing the Influence of Data Homogenization versus Model Forcings

2007 ◽  
Vol 20 (21) ◽  
pp. 5356-5364 ◽  
Author(s):  
John R. Lanzante
Keyword(s):  
Climate Model ◽  
Temperature Response ◽  
Volcanic Eruptions ◽  
Human Influence ◽  
Vertical Temperature ◽  
Upper Troposphere ◽  
Temperature Trends ◽  
Versus Model ◽  
Time Period ◽  
Climate Forcings

Abstract Measurements from radiosonde temperatures have been used in studies that seek to identify the human influence on climate. However, such measurements are known to be contaminated by artificial inhomogeneities introduced by changes in instruments and recording practices that have occurred over time. Some simple diagnostics are used to compare vertical profiles of temperature trends from the observed data with simulations from a GCM driven by several different sets of forcings. Unlike most earlier studies of this type, both raw (i.e., fully contaminated) as well as adjusted observations (i.e., treated to remove some of the contamination) are utilized. The comparisons demonstrate that the effect of observational data adjustment can be as important as the inclusion of some major climate forcings in the model simulations. The effects of major volcanic eruptions critically influence temperature trends, even over a time period nearly four decades in length. In addition, it is seen that the adjusted data show consistently better agreement than the unadjusted data, with simulations from a climate model for 1959–97. Particularly noteworthy is the fact that the adjustments supply missing warming in the tropical upper troposphere that has been attributed to model error in a number of earlier studies. Finally, an evaluation of the fidelity of the model’s temperature response to major volcanic eruptions is conducted. Although the major conclusions of this study are unaffected by shortcomings of the simulations, they highlight the fact that even using a fairly long period of record (∼40 yr), any such shortcomings can have an important impact on trends and trend comparisons.

scholarly journals The unidentified volcanic eruption of 1809: why it remains a climatic cold case

2021 ◽  
Author(s):  
Claudia Timmreck ◽  
Matthew Toohey ◽  
Davide Zanchettin ◽  
Stefan Brönnimann ◽  
Elin Lundstadt ◽  
...  
Keyword(s):  
Large Scale ◽  
Volcanic Eruptions ◽  
Climate Impact ◽  
Summer Temperature ◽  
Boreal Summer ◽  
Significant Drop ◽  
Model Simulations ◽  
Temperature Anomalies ◽  
Reconstructed Temperature ◽  
Volcanic Forcing

Abstract. The 1809 eruption is one of the most recent unidentified volcanic eruptions with a global climate impact. Even though the eruption ranks as the 3rd largest since 1500 with an eruption magnitude estimated to be two times that of the 1991 eruption of Pinatubo, not much is known of it from historic sources. Based on a compilation of instrumental and reconstructed temperature time series, we show here that tropical temperatures show a significant drop in response to the ~1809 eruption, similar to that produced by the Mt. Tambora eruption in 1815, while the response of Northern Hemisphere (NH) boreal summer temperature is spatially heterogeneous. We test the sensitivity of the climate response simulated by the MPI Earth system model to a range of volcanic forcing estimates constructed using estimated volcanic stratospheric sulfur injections (VSSI) and uncertainties from ice core records. Three of the forcing reconstructions represent a tropical eruption with approximately symmetric hemispheric aerosol spread but different forcing magnitudes, while a fourth reflects a hemispherically asymmetric scenario without volcanic forcing in the NH extratropics. Observed and reconstructed post-volcanic surface NH summer temperature anomalies lie within the range of all the scenario simulations. Therefore, assuming the model climate sensitivity is correct, the VSSI estimate is accurate within the uncertainty bounds. Comparison of observed and simulated tropical temperature anomalies suggests that the most likely VSSI for the 1809 eruption would be somewhere between 12–19 Tg of sulfur. Model results show that NH large-scale climate modes are sensitive to both volcanic forcing strength and its spatial structure. While spatial correlations between the N-TREND NH temperature reconstruction and the model simulations are weak in terms of the ensemble mean model results, individual model simulations show good correlation over North America and Europe, suggesting the spatial heterogeneity of the 1810 cooling could be due to internal climate variability.

scholarly journals Effects of Memory Biases on Variability of Temperature Reconstructions

2019 ◽  
Vol 32 (24) ◽  
pp. 8713-8731 ◽  
Author(s):  
Lucie J. Lücke ◽  
Gabriele C. Hegerl ◽  
Andrew P. Schurer ◽  
Rob Wilson
Keyword(s):  
Tree Ring ◽  
Climate Models ◽  
Climate Model ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Ice Age ◽  
Detection And Attribution ◽  
Reconstructed Temperature ◽  
Tree Ring Data ◽  
The Difference

Abstract Quantifying past climate variation and attributing its causes improves our understanding of the natural variability of the climate system. Tree-ring-based proxies have provided skillful and highly resolved reconstructions of temperature and hydroclimate of the last millennium. However, like all proxies, they are subject to uncertainties arising from varying data quality, coverage, and reconstruction methodology. Previous studies have suggested that biological-based memory processes could cause spectral biases in climate reconstructions. This study determines the effects of such biases on reconstructed temperature variability and the resultant implications for detection and attribution studies. We find that introducing persistent memory, reflecting the spectral properties of tree-ring data, can change the variability of pseudoproxy reconstructions compared to the surrogate climate and resolve certain model–proxy discrepancies. This is especially the case for proxies based on ring-width data. Such memory inflates the difference between the Medieval Climate Anomaly and the Little Ice Age and suppresses and extends the cooling in response to volcanic eruptions. When accounting for memory effects, climate model data can reproduce long-term cooling after volcanic eruptions, as seen in proxy reconstructions. Results of detection and attribution studies show that signals in reconstructions as well as residual unforced variability are consistent with those in climate models when the model fingerprints are adjusted to reflect autoregressive memory as found in tree rings.

scholarly journals The unidentified eruption of 1809: a climatic cold case

2021 ◽  
Vol 17 (4) ◽  
pp. 1455-1482
Author(s):  
Claudia Timmreck ◽  
Matthew Toohey ◽  
Davide Zanchettin ◽  
Stefan Brönnimann ◽  
Elin Lundstad ◽  
...  
Keyword(s):  
Large Scale ◽  
Volcanic Eruptions ◽  
Climate Impact ◽  
Summer Temperature ◽  
Boreal Summer ◽  
Significant Drop ◽  
Model Simulations ◽  
Temperature Anomalies ◽  
Reconstructed Temperature ◽  
Volcanic Forcing

Abstract. The “1809 eruption” is one of the most recent unidentified volcanic eruptions with a global climate impact. Even though the eruption ranks as the third largest since 1500 with a sulfur emission strength estimated to be 2 times that of the 1991 eruption of Pinatubo, not much is known of it from historic sources. Based on a compilation of instrumental and reconstructed temperature time series, we show here that tropical temperatures show a significant drop in response to the ∼ 1809 eruption that is similar to that produced by the Mt. Tambora eruption in 1815, while the response of Northern Hemisphere (NH) boreal summer temperature is spatially heterogeneous. We test the sensitivity of the climate response simulated by the MPI Earth system model to a range of volcanic forcing estimates constructed using estimated volcanic stratospheric sulfur injections (VSSIs) and uncertainties from ice-core records. Three of the forcing reconstructions represent a tropical eruption with an approximately symmetric hemispheric aerosol spread but different forcing magnitudes, while a fourth reflects a hemispherically asymmetric scenario without volcanic forcing in the NH extratropics. Observed and reconstructed post-volcanic surface NH summer temperature anomalies lie within the range of all the scenario simulations. Therefore, assuming the model climate sensitivity is correct, the VSSI estimate is accurate within the uncertainty bounds. Comparison of observed and simulated tropical temperature anomalies suggests that the most likely VSSI for the 1809 eruption would be somewhere between 12 and 19 Tg of sulfur. Model results show that NH large-scale climate modes are sensitive to both volcanic forcing strength and its spatial structure. While spatial correlations between the N-TREND NH temperature reconstruction and the model simulations are weak in terms of the ensemble-mean model results, individual model simulations show good correlation over North America and Europe, suggesting the spatial heterogeneity of the 1810 cooling could be due to internal climate variability.

The unidentified volcanic eruption of ~1809: why it remains a climatic cold case

2021 ◽  
Author(s):  
Claudia Timmreck ◽  
Matthew Toohey ◽  
Davide Zanchettin ◽  
Stefan Brönnimann ◽  
Elin Lundstadt ◽  
...  
Keyword(s):  
Large Scale ◽  
Volcanic Eruptions ◽  
Climate Impact ◽  
Summer Temperature ◽  
Boreal Summer ◽  
Significant Drop ◽  
Model Simulations ◽  
Temperature Anomalies ◽  
Reconstructed Temperature ◽  
Volcanic Forcing

<p>The  "1809 eruption” is one of the most recent unidentified volcanic eruptions with a global climate impact. Even though the eruption ranks as the 3rd largest since 1500 with an eruption magnitude estimated to be two times that of the 1991 eruption of Pinatubo, not much is known of it from historic sources. Based on a compilation of instrumental and reconstructed temperature time series, we show here that tropical temperatures show a significant drop in response to the ~1809 eruption, similar to that produced by the Mt. Tambora eruption in 1815, while the response of Northern Hemisphere (NH) boreal summer temperature is spatially heterogeneous.  Here, we present the sensitivity of the climate response simulated by the MPI Earth system model to a range of volcanic forcing estimates constructed using estimated volcanic stratospheric sulfur injections (VSSI) and uncertainties from ice core records. Three of the forcing reconstructions represent a tropical eruption with approximately symmetric hemispheric aerosol spread but different forcing magnitudes, while a fourth reflects a hemispherically asymmetric scenario without volcanic forcing in the NH extratropics. Observed and reconstructed post-volcanic surface NH summer temperature anomalies lie within the range of all the scenario simulations. Therefore, assuming the model climate sensitivity is correct, the VSSI estimate is accurate within the uncertainty bounds. Comparison of observed and simulated tropical temperature anomalies suggests that the most likely VSSI for the 1809 eruption would be somewhere between 12 -19 Tg of sulfur. Model results show that NH large-scale climate modes are sensitive to both volcanic forcing strength and its spatial structure.  While spatial correlations between the N-TREND NH temperature reconstruction and the model simulations are weak in terms of the ensemble mean model results, individual model simulations show good correlation over North America and Europe, suggesting the spatial heterogeneity of the 1810 cooling could be due to internal climate variability. </p>

scholarly journals Volcanic forcing for climate modeling: a new microphysics-based dataset covering years 1600–present

2013 ◽  
Vol 9 (1) ◽  
pp. 967-1012 ◽  
Author(s):  
F. Arfeuille ◽  
D. Weisenstein ◽  
H. Mack ◽  
E. Rozanov ◽  
T. Peter ◽  
...  
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
Climate Modeling ◽  
Circulation Model ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Global Scale ◽  
Stratospheric Aerosol ◽  
Sulfate Aerosols ◽  
Volcanic Forcing

Abstract. As the understanding and representation of the impacts of volcanic eruptions on climate have improved in the last decades, uncertainties in the stratospheric aerosol forcing from large eruptions are now not only linked to visible optical depth estimates on a global scale but also to details on the size, latitude and altitude distributions of the stratospheric aerosols. Based on our understanding of these uncertainties, we propose a new model-based approach to generating a volcanic forcing for General-Circulation-Model (GCM) and Chemistry-Climate-Model (CCM) simulations. This new volcanic forcing, covering the 1600–present period, uses an aerosol microphysical model to provide a realistic, physically consistent treatment of the stratospheric sulfate aerosols. Twenty-six eruptions were modeled individually using the latest available ice cores aerosol mass estimates and historical data on the latitude and date of eruptions. The evolution of aerosol spatial and size distribution after the sulfur dioxide discharge are hence characterized for each volcanic eruption. Large variations are seen in hemispheric partitioning and size distributions in relation to location/date of eruptions and injected SO2 masses. Results for recent eruptions are in good agreement with observations. By providing accurate amplitude and spatial distributions of shortwave and longwave radiative perturbations by volcanic sulfate aerosols, we argue that this volcanic forcing may help refine the climate model responses to the large volcanic eruptions since 1600. The final dataset consists of 3-D values (with constant longitude) of spectrally resolved extinction coefficients, single scattering albedos and asymmetry factors calculated for different wavelength bands upon request. Surface area densities for heterogeneous chemistry are also provided.

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