scholarly journals The potential impacts of a sulfur- and halogen-rich supereruption such as Los Chocoyos on the atmosphere and climate

2020 ◽  
Vol 20 (11) ◽  
pp. 6521-6539 ◽  
Author(s):  
Hans Brenna ◽  
Steffen Kutterolf ◽  
Michael J. Mills ◽  
Kirstin Krüger
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Net Primary Production ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Surface Cooling ◽  
Aerosol Chemistry ◽  
Surface Climate ◽  
Column Ozone

Abstract. The supereruption of Los Chocoyos (14.6∘ N, 91.2∘ W) in Guatemala ∼84 kyr ago was one of the largest volcanic events of the past 100 000 years. Recent petrologic data show that the eruption released very large amounts of climate-relevant sulfur and ozone-destroying chlorine and bromine gases (523±94 Mt sulfur, 1200±156 Mt chlorine, and 2±0.46 Mt bromine). Using the Earth system model (ESM) of the Community Earth System Model version 2 (CESM2) coupled with the Whole Atmosphere Community Climate Model version 6 (WACCM6), we simulated the impacts of the sulfur- and halogen-rich Los Chocoyos eruption on the preindustrial Earth system. Our simulations show that elevated sulfate burden and aerosol optical depth (AOD) persists for 5 years in the model, while the volcanic halogens stay elevated for nearly 15 years. As a consequence, the eruption leads to a collapse of the ozone layer with global mean column ozone values dropping to 50 DU (80 % decrease) and leading to a 550 % increase in surface UV over the first 5 years, with potential impacts on the biosphere. The volcanic eruption shows an asymmetric-hemispheric response with enhanced aerosol, ozone, UV, and climate signals over the Northern Hemisphere. Surface climate is impacted globally due to peak AOD of >6, which leads to a maximum surface cooling of >6 K, precipitation and terrestrial net primary production decrease of >25 %, and sea ice area increases of 40 % in the first 3 years. Locally, a wetting (>100 %) and strong increase in net primary production (NPP) (>700 %) over northern Africa is simulated in the first 5 years and related to a southward shift of the Intertropical Convergence Zone (ITCZ) to the southern tropics. The ocean responds with pronounced El Niño conditions in the first 3 years that shift to the southern tropics and are coherent with the ITCZ change. Recovery to pre-eruption ozone levels and climate takes 15 years and 30 years, respectively. The long-lasting surface cooling is sustained by an immediate increase in the Arctic sea ice area, followed by a decrease in poleward ocean heat transport at 60∘ N which lasts up to 20 years. In contrast, when simulating Los Chocoyos conventionally by including sulfur and neglecting halogens, we simulate a larger sulfate burden and AOD, more pronounced surface climate changes, and an increase in column ozone. By comparing our aerosol chemistry ESM results to other supereruption simulations with aerosol climate models, we find a higher surface climate impact per injected sulfur amount than previous studies for our different sets of model experiments, since the CESM2(WACCM6) creates smaller aerosols with a longer lifetime, partly due to the interactive aerosol chemistry. As the model uncertainties for the climate response to supereruptions are very large, observational evidence from paleo archives and a coordinated model intercomparison would help to improve our understanding of the climate and environment response.

scholarly journals The sulfur- and halogen-rich super eruption Los Chocoyos and its impacts on climate and environment

2019 ◽  
Author(s):  
Hans Brenna ◽  
Steffen Kutterolf ◽  
Michael J. Mills ◽  
Kirstin Krüger
Keyword(s):  
Sea Ice ◽  
Net Primary Production ◽  
The Arctic ◽  
Strong Increase ◽  
Earth System ◽  
Surface Cooling ◽  
Aerosol Chemistry ◽  
Inter Tropical Convergence Zone ◽  
Surface Climate ◽  
Column Ozone

Abstract. The super-eruption of Los Chocoyos, newly dated to 80.6 kyrs ago, in Guatemala was one of the largest volcanic events of the past 100 000 years. Recent petrologic data show that the eruption released very large amounts of climate-relevant sulfur and ozone destroying chlorine and bromine gases. Using the recently released Earth System Model CESM2(WACCM6) we simulate the impacts of the sulfur- and halogen-rich Los Chocoyos (~ 15° N) eruption on the pre-industrial Earth System for the eruption month January. Our model results show that enhanced modeled sulfate burden and aerosol optical depth (AOD) persists for five years, while the volcanic halogens stay elevated for nearly 15 years. As a consequence the eruption leads to a collapse of the ozone layer with global mean column ozone values dropping to 50 DU (80 % decrease) leading to a 550 % increase in surface UV over the first five years with potential impacts on the biosphere. The volcanic eruption shows an asymmetric hemispheric response with enhanced aerosol, ozone, UV, and climate signals over the Northern Hemisphere (NH). Surface climate is impacted globally due to peak AOD of > 6 leading to a maximum surface cooling of > 6 K, precipitation and terrestrial net primary production (NPP) decreases of > 25 %, and sea ice area increases of 40 % in the first three years. Locally, a wetting (> 100 %) and strong increase of NPP (> 700 %) over Northern Africa is simulated in the first five years related to a southwards shift of the Inter-Tropical Convergence Zone to the southern tropics. The ocean responds with El-Niño conditions in the first two years which are masked by the strong volcanic induced surface cooling. Recovery to pre-eruption ozone levels and climate takes 15 and 30 years respectively. The long lasting surface cooling is sustained by sea ice/ocean changes in the Arctic showing an immediate sea ice area increase followed by a decrease of poleward ocean heat transport at 60° N lasting up to 20 years. In contrast, when simulating Los Chocoyos conventionally, including sulfur and neglecting halogens, we simulate larger sulfate burden and AOD, more pronounced surface climate changes and an increase of column ozone. Comparing our aerosol chemistry ESM results to other super-eruption simulations with aerosol climate models we find a higher surface climate impact per injected sulfur amount than previous studies for our different sets of model experiments, since CESM2(WACCM6) creates smaller aerosols with a longer lifetime partly due to the interactive aerosol chemistry. As the model uncertainties for the climate response to super eruptions are very large observational evidence from paleo archives and a coordinated model intercomparison would help to improve our understanding of the climate and environment response.

scholarly journals Marine biogeochemical cycling and oceanic CO<sub>2</sub> uptake simulated by the NUIST Earth System Model version 3

2019 ◽  
Author(s):  
Yifei Dai ◽  
Long Cao ◽  
Bin Wang
Keyword(s):  
Primary Production ◽  
Large Scale ◽  
Net Primary Production ◽  
Earth System Model ◽  
System Model ◽  
Upper Ocean ◽  
Carbon Uptake ◽  
Co2 Uptake ◽  
Earth System ◽  
Cmip5 Model

Abstract. In this study, we evaluate the performance of Nanjing University of Information Science and Technology Earth System Model, version 3 (hereafter NESM v3) in simulating the marine biogeochemical cycle and CO2 uptake. Compared with observations, NESM v3 reproduces reasonably well the large-scale patterns of upper ocean biogeochemical fields including nutrients, alkalinity, dissolved inorganic, chlorophyll, and net primary production. The model also reasonably reproduces current-day oceanic CO2 uptake, the total CO2 uptake is 149 PgC from 1850 to 2016. In the 1ptCO2 experiment, the NESM v3 produced carbon-climate (γ=-7.9 PgC/K) and carbon-concentration sensitivity parameters (β=0.8 PgC/ppm) are comparable with CMIP5 model results. The nonlinearity of carbon uptake in the NESM v3 accounts for 10.3% of the total carbon uptake, which is within the range of CMIP5 model results (3.6%~10.6%). Some regional discrepancies between model simulations and observations are identified and the possible causes are investigated. In the upper ocean, the simulated biases in biogeochemical fields are mainly associated with the shortcoming in simulated ocean circulation. Weak upwelling in the Indian Ocean suppresses the nutrient entrainment to the upper ocean, therefore reducing the biological activities and resulting in underestimation of net primary production and chlorophyll concentration. In the Pacific and the Southern Ocean, high-nutrient and low-chlorophyll result from the strong iron limitation. Alkalinity shows high biases in high-latitude oceans due to the strong convective mixing. The major discrepancy in biogeochemical fields is seen in the deep Northern Pacific. The simulated high concentration of nutrients, alkalinity and dissolved inorganic carbon water is too deep due to the excessive deep ocean remineralization. Despite these model-observation discrepancies, it is expected that the NESM v3 can be employed as a useful modeling tool to investigate large scale interactions between the ocean carbon cycle and climate change.

scholarly journals Marine biogeochemical cycling and oceanic CO<sub>2</sub> uptake simulated by the NUIST Earth System Model version 3 (NESM v3)

2020 ◽  
Vol 13 (7) ◽  
pp. 3119-3144
Author(s):  
Yifei Dai ◽  
Long Cao ◽  
Bin Wang
Keyword(s):  
Primary Production ◽  
Carbon Concentration ◽  
Large Scale ◽  
Net Primary Production ◽  
Earth System Model ◽  
System Model ◽  
Upper Ocean ◽  
Co2 Uptake ◽  
Earth System ◽  
Model Version

Abstract. In this study, we evaluate the performance of the Nanjing University of Information Science and Technology (NUIST) Earth System Model version 3 (hereafter NESM v3) in simulating the marine biogeochemical cycle and carbon dioxide (CO2) uptake. Compared with observations, the NESM v3 reproduces the large-scale patterns of biogeochemical fields reasonably well in the upper ocean, including nutrients, alkalinity, dissolved inorganic, chlorophyll, and net primary production. Some discrepancies between model simulations and observations are identified and the possible causes are investigated. In the upper ocean, the simulated biases in biogeochemical fields are mainly associated with shortcomings in the simulated ocean circulation. Weak upwelling in the Indian Ocean suppresses the nutrient entrainment to the upper ocean, thus reducing biological activities and resulting in an underestimation of net primary production and the chlorophyll concentration. In the Pacific and the Southern Ocean, nutrients are overestimated as a result of strong iron limitation and excessive vertical mixing. Alkalinity is also overestimated in high-latitude oceans due to excessive convective mixing. The major discrepancy in biogeochemical fields is that the model overestimates nutrients, alkalinity, and dissolved inorganic carbon in the deep North Pacific, which is caused by the excessive deep ocean remineralization. The model reasonably reproduces present-day oceanic CO2 uptake. Model-simulated cumulative oceanic CO2 uptake is 149 PgC between 1850 and 2016, which compares well with data-based estimates of 150±20 PgC. In the 1 % yr−1 CO2 increase (1ptCO2) experiment, the diagnosed carbon-climate (γ=-7.9 PgC K−1) and carbon-concentration sensitivity parameters (β=0.88 PgC ppm−1) in the NESM v3 are comparable with those in Coupled Model Intercomparison Project phase 5 (CMIP5) models (β: 0.69 to 0.91 PgC ppm−1; γ: −2.4 to −12.1 PgC K−1). The nonlinear interaction between carbon-concentration and carbon-climate sensitivity in the NESM v3 accounts for 10.3 % of the total carbon uptake, which is within the range of CMIP5 model results (3.6 %–10.6 %). Overall, the NESM v3 can be employed as a useful modeling tool to investigate large-scale interactions between the ocean carbon cycle and climate change.

scholarly journals A comparison of plot-based satellite and Earth system model estimates of tropical forest net primary production

2015 ◽  
Vol 29 (5) ◽  
pp. 626-644 ◽  
Author(s):  
Cory C. Cleveland ◽  
Philip Taylor ◽  
K. Dana Chadwick ◽  
Kyla Dahlin ◽  
Christopher E. Doughty ◽  
...  
Keyword(s):  
Primary Production ◽  
Tropical Forest ◽  
Net Primary Production ◽  
Earth System Model ◽  
System Model ◽  
Earth System

scholarly journals Canadian snow and sea ice: assessment of snow, sea ice, and related climate processes in Canada's Earth system model and climate-prediction system

2018 ◽  
Vol 12 (4) ◽  
pp. 1137-1156 ◽  
Author(s):  
Paul J. Kushner ◽  
Lawrence R. Mudryk ◽  
William Merryfield ◽  
Jaison T. Ambadan ◽  
Aaron Berg ◽  
...  
Keyword(s):  
Sea Ice ◽  
Snow Cover ◽  
Climate Prediction ◽  
Earth System Model ◽  
System Model ◽  
Prediction System ◽  
Earth System ◽  
Seasonal Snow ◽  
Observational Uncertainty ◽  
Seasonal Snow Cover

Abstract. The Canadian Sea Ice and Snow Evolution (CanSISE) Network is a climate research network focused on developing and applying state-of-the-art observational data to advance dynamical prediction, projections, and understanding of seasonal snow cover and sea ice in Canada and the circumpolar Arctic. This study presents an assessment from the CanSISE Network of the ability of the second-generation Canadian Earth System Model (CanESM2) and the Canadian Seasonal to Interannual Prediction System (CanSIPS) to simulate and predict snow and sea ice from seasonal to multi-decadal timescales, with a focus on the Canadian sector. To account for observational uncertainty, model structural uncertainty, and internal climate variability, the analysis uses multi-source observations, multiple Earth system models (ESMs) in Phase 5 of the Coupled Model Intercomparison Project (CMIP5), and large initial-condition ensembles of CanESM2 and other models. It is found that the ability of the CanESM2 simulation to capture snow-related climate parameters, such as cold-region surface temperature and precipitation, lies within the range of currently available international models. Accounting for the considerable disagreement among satellite-era observational datasets on the distribution of snow water equivalent, CanESM2 has too much springtime snow mass over Canada, reflecting a broader northern hemispheric positive bias. Biases in seasonal snow cover extent are generally less pronounced. CanESM2 also exhibits retreat of springtime snow generally greater than observational estimates, after accounting for observational uncertainty and internal variability. Sea ice is biased low in the Canadian Arctic, which makes it difficult to assess the realism of long-term sea ice trends there. The strengths and weaknesses of the modelling system need to be understood as a practical tradeoff: the Canadian models are relatively inexpensive computationally because of their moderate resolution, thus enabling their use in operational seasonal prediction and for generating large ensembles of multidecadal simulations. Improvements in climate-prediction systems like CanSIPS rely not just on simulation quality but also on using novel observational constraints and the ready transfer of research to an operational setting. Improvements in seasonal forecasting practice arising from recent research include accurate initialization of snow and frozen soil, accounting for observational uncertainty in forecast verification, and sea ice thickness initialization using statistical predictors available in real time.

scholarly journals Description and evaluation of NorESM1-F: A fast version of the Norwegian Earth System Model (NorESM)

2018 ◽  
Author(s):  
Chuncheng Guo ◽  
Mats Bentsen ◽  
Ingo Bethke ◽  
Mehmet Ilicak ◽  
Jerry Tjiputra ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Sea Ice ◽  
Large Scale ◽  
Coupled Model ◽  
Coupled System ◽  
Internal Variability ◽  
Earth System Model ◽  
Meridional Overturning Circulation ◽  
System Model ◽  
Earth System

Abstract. A new computationally efficient version of the Norwegian Earth System Model (NorESM) is presented. This new version (here termed NorESM1-F) runs about 2.5 times faster (e.g. 90 model years per day on current hardware) than the version that contributed to the fifth phase of the Coupled Model Intercomparison project (CMIP5), i.e., NorESM1-M, and is therefore particularly suitable for multi-millennial paleoclimate and carbon cycle simulations or large ensemble simulations. The speedup is primarily a result of using a prescribed atmosphere aerosol chemistry and a tripolar ocean-sea ice horizontal grid configuration that allows an increase of the ocean-sea ice component time steps. Ocean biogeochemistry can be activated for fully coupled and semi-coupled carbon cycle applications. This paper describes the model and evaluates its performance using observations and NorESM1-M as benchmarks. The evaluation emphasises model stability, important large-scale features in the ocean and sea ice components, internal variability in the coupled system, and climate sensitivity. Simulation results from NorESM1-F in general agree well with observational estimates, and show evident improvements over NorESM1-M, for example, in the strength of the meridional overturning circulation and sea ice simulation, both important metrics in simulating past and future climates. Whereas NorESM1-M showed a slight global cool bias in the upper oceans, NorESM1-F exhibits a global warm bias. In general, however, NorESM1-F has more similarities than dissimilarities compared to NorESM1-M, and some biases and deficiencies known in NorESM1-M remain.

Aerosols and their impacts on future Arctic climate change under different emission projections in the GISS-E2.1 Earth system model

2021 ◽  
Author(s):  
Ulas Im ◽  
Kostas Tsigaridis ◽  
Gregory S. Faluvegi ◽  
Peter L. Langen ◽  
Joshua P. French ◽  
...  
Keyword(s):  
Sea Ice ◽  
Earth System Model ◽  
System Model ◽  
The Arctic ◽  
Earth System ◽  
Anthropogenic Aerosols ◽  
Emission Reductions ◽  
Air Temperatures ◽  
The Future ◽  
Emission Projections

&lt;p&gt;In order to study the future aerosol burdens and their radiative and climate impacts over the Arctic (&gt;60 &amp;#176;N), future (2015-2050) simulations have been carried out using the GISS-E2.1 Earth system model. Different future anthrpogenic emission projections have been used from the Eclipse V6b and the Coupled Model Intercomparison Project Phase 6 (CMIP6) databases. Results showed that&amp;#160;Arctic BC, OC and SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt; burdens decrease significantly in all simulations following the emission projections, with the CMIP6 ensemble showing larger reductions in Arctic aerosol burdens compared to the Eclipse ensemble. For the 2030-2050 period, both the Eclipse Current Legislation (CLE) and the Maximum Feasible Reduction (MFR) ensembles simulated an aerosol top of the atmosphere (TOA) forcing of -0.39&amp;#177;0.01 W m&lt;sup&gt;-2&lt;/sup&gt;, of which -0.24&amp;#177;0.01 W m&lt;sup&gt;-2&lt;/sup&gt; were attributed to the anthropogenic aerosols. The CMIP6 SSP3-7.0 scenario simulated a TOA aerosol forcing of -0.35 W m&lt;sup&gt;-2&lt;/sup&gt; for the same period, while SSP1-2.6 and SSP2-4.5 scenarios simulated a slightly more negative TOA forcing (-0.40 W m&lt;sup&gt;-2&lt;/sup&gt;), of which the anthropogenic aerosols accounted for -0.26 W m&lt;sup&gt;-2&lt;/sup&gt;. The 2030-2050 mean surface air temperatures are projected to increase by 2.1 &amp;#176;C and 2.4 &amp;#176;C compared to the 1990-2010 mean temperature according to the Eclipse CLE and MFR ensembles, respectively, while the CMIP6 simulation calculated an increase of 1.9 &amp;#176;C (SSP1-2.6) to 2.2 &amp;#176;C (SSP3-7.0). Overall, results show that even the scenarios with largest emission reductions lead to similar impact on the future Arctic surface air temperatures compared to scenarios with smaller emission reductions, while scenarios with no or little mitigation leads to much larger sea-ice loss, implying that even though the magnitude of aerosol reductions lead to similar responses in surface air temperatures, high mitigation of aerosols are still necessary to limit sea-ice loss.&amp;#160;&lt;/p&gt;

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