Large-scale features of Last Interglacial climate : Results from evaluating the lig127k simulations for the Coupled Model Intercomparison Project (CMIP6)-Paleoclimate Modeling Intercomparison Project (PMIP4)
National Center for Atmospheric Research1, University College London2, Northwestern University3, University of Copenhagen4, Université Paris-Saclay5, Virginia Commonwealth University6, Science Museum of Virginia7, VU University Amsterdam8, University of Bristol9, University of Cambridge10, University of Tokyo11, University of Toulouse12, Nanjing University13, Université du Québec à Montréal14, British Antarctic Survey15, Bjerknes Centre for Climate Research16, Goddard Institute for Space Studies17, Alfred Wegener Institute for Polar and Marine Research18, University of New South Wales19, Russian Academy of Sciences20, University of Oslo21, University of Bergen22, Russian Academy23, Stockholm University24, China University of Geosciences (Wuhan)25, Chinese Academy of Sciences26
TL;DR: In this paper, a multi-model ensemble of 17 climate models, all of which have completed the Coupled Model Intercomparison Project (CMIP6) DECK (Diagnostic, Evaluation and Characterization of Klima) experiments, is presented.
Abstract: The modeling of paleoclimate, using physically based tools, is increasingly seen as a strong out-of-sample test of the models that are used for the projection of future climate changes. New to the Coupled Model Intercomparison Project (CMIP6) is the Tier 1 Last Interglacial experiment for 127 000 years ago (lig127k), designed to address the climate responses to stronger orbital forcing than the midHolocene experiment, using the same state-of-the-art models as for the future and following a common experimental protocol. Here we present a first analysis of a multi-model ensemble of 17 climate models, all of which have completed the CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima) experiments. The equilibrium climate sensitivity (ECS) of these models varies from 1.8 to 5.6 ∘C. The seasonal character of the insolation anomalies results in strong summer warming over the Northern Hemisphere continents in the lig127k ensemble as compared to the CMIP6 piControl and much-reduced minimum sea ice in the Arctic. The multi-model results indicate enhanced summer monsoonal precipitation in the Northern Hemisphere and reductions in the Southern Hemisphere. These responses are greater in the lig127k than the CMIP6 midHolocene simulations as expected from the larger insolation anomalies at 127 than 6 ka.
New synthesis for surface temperature and precipitation, targeted for 127 ka, have been developed for comparison to the multi-model ensemble. The lig127k model ensemble and data reconstructions are in good agreement for summer temperature anomalies over Canada, Scandinavia, and the North Atlantic and for precipitation over the Northern Hemisphere continents. The model–data comparisons and mismatches point to further study of the sensitivity of the simulations to uncertainties in the boundary conditions and of the uncertainties and sparse coverage in current proxy reconstructions.
The CMIP6–Paleoclimate Modeling Intercomparison Project (PMIP4) lig127k simulations, in combination with the proxy record, improve our confidence in future projections of monsoons, surface temperature, and Arctic sea ice, thus providing a key target for model evaluation and optimization.
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TL;DR: In this paper, the PMIP4 experiments with EC-Earth3-LR were used to compare the model's ability to capture the climate response under different climate forcings, providing potential implications for confidence in future projections.
Abstract: . As global warming is proceeding due to rising greenhouse
gas concentrations, the Earth system moves towards climate states that
challenge adaptation. Past Earth system states are offering possible
modelling systems for the global warming of the coming decades. These
include the climate of the mid-Pliocene ( ∼ 3 Ma), the last
interglacial ( ∼ 129–116 ka) and the mid-Holocene
( ∼ 6 ka). The simulations for these past warm periods are the
key experiments in the Paleoclimate Model Intercomparison Project (PMIP)
phase 4, contributing to phase 6 of the Coupled Model Intercomparison Project (CMIP6).
Paleoclimate modelling has long been regarded as a robust out-of-sample
test bed of the climate models used to project future climate changes. Here,
we document the model setup for PMIP4 experiments with EC-Earth3-LR and
present the large-scale features from the simulations for the mid-Holocene,
the last interglacial and the mid-Pliocene. Using the pre-industrial
climate as a reference state, we show global temperature changes,
large-scale Hadley circulation and Walker circulation, polar warming, global
monsoons and the climate variability modes – El Nino–Southern Oscillation
(ENSO), the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO).
EC-Earth3-LR simulates reasonable climate responses during past warm
periods, as shown in the other PMIP4-CMIP6 model ensemble. The systematic
comparison of these climate changes in past three warm periods in an
individual model demonstrates the model's ability to capture the climate
response under different climate forcings, providing potential implications
for confidence in future projections with the EC-Earth model.
31 citations
TL;DR: In this paper, the authors used the Model forInterdisciplinary Research on Climate, Earth System version 2 for Long-term simulations (MIROC-ES2L), which is an Earth system model.
Abstract: . Following the protocol of the fourth phase of the Paleoclimate
Modelling Intercomparison Project (PMIP4), we performed numerical experiments
targeting distinctive past time periods using the Model for
Interdisciplinary Research on Climate, Earth System version 2 for Long-term
simulations (MIROC-ES2L), which is an Earth system model. Setup and basic
performance of the experiments are presented. The Last Glacial Maximum was one of the most extreme climate states during
the Quaternary and conducting numerical modeling experiments of this period
has long been a challenge for the paleoclimate community. We conducted a
Last Glacial Maximum experiment with a long spin-up of nearly 9000 years.
Globally, there was reasonable agreement between the anomalies relative to the present day derived from model climatology and those derived from proxy data archives, while some regional discrepancies remained. By changing orbital and greenhouse gas forcings, we conducted experiments
for two interglacial periods: 6000 and 127 000 years before present. Model
anomalies relative to the present day were qualitatively consistent with
variations in solar forcing. However, anomalies in the model were smaller
than those derived from proxy data archives, suggesting that processes that
play a role in past interglacial climates remain lacking in this
state-of-the-art model. We conducted transient simulations from 850 to 1850 CE and from 1850
to 2014 CE. Cooling in the model indicated a clear response to huge volcanic
eruptions, consistent with paleo-proxy data. The contrast between cooling
during the Little Ice Age and warming during the 20th to 21st
centuries was represented well at the multidecadal timescale.
28 citations
Université Paris-Saclay1, British Antarctic Survey2, Université du Québec à Montréal3, University of Bremen4, Alfred Wegener Institute for Polar and Marine Research5, University of Reading6, University of Tokyo7, University of Washington8, National Center for Atmospheric Research9, Nanjing University of Information Science and Technology10, Hobart Corporation11, Bjerknes Centre for Climate Research12, Goddard Institute for Space Studies13, University of New South Wales14, Russian Academy of Sciences15, University of Oslo16, Centre national de la recherche scientifique17, University of Manitoba18, Stockholm University19, China University of Geosciences (Wuhan)20, Chinese Academy of Sciences21, Commonwealth Scientific and Industrial Research Organisation22
TL;DR: In this paper, the results from 16 climate models in terms of Arctic sea ice were analyzed and compared to the results of the Coupled Model Intercomparison Project (CMP).
Abstract: The Last Interglacial period (LIG) is a period with increased summer insolation at high northern latitudes, which results in strong changes in the terrestrial and marine cryosphere. Understanding the mechanisms for this response via climate modelling and comparing the models' representation of climate reconstructions is one of the objectives set up by the Paleoclimate Modelling Intercomparison Project for its contribution to the sixth phase of the Coupled Model Intercomparison Project. Here we analyse the results from 16 climate models in terms of Arctic sea ice. The multi-model mean reduction in minimum sea ice area from the pre industrial period (PI) to the LIG reaches 50 % (multi-model mean LIG area is 3.20×106 km2, compared to 6.46×106 km2 for the PI). On the other hand, there is little change for the maximum sea ice area (which is 15–16×106 km2 for both the PI and the LIG. To evaluate the model results we synthesise LIG sea ice data from marine cores collected in the Arctic Ocean, Nordic Seas and northern North Atlantic. The reconstructions for the northern North Atlantic show year-round ice-free conditions, and most models yield results in agreement with these reconstructions. Model–data disagreement appear for the sites in the Nordic Seas close to Greenland and at the edge of the Arctic Ocean. The northernmost site with good chronology, for which a sea ice concentration larger than 75 % is reconstructed even in summer, discriminates those models which simulate too little sea ice. However, the remaining models appear to simulate too much sea ice over the two sites south of the northernmost one, for which the reconstructed sea ice cover is seasonal. Hence models either underestimate or overestimate sea ice cover for the LIG, and their bias does not appear to be related to their bias for the pre-industrial period. Drivers for the inter-model differences are different phasing of the up and down short-wave anomalies over the Arctic Ocean, which are associated with differences in model albedo; possible cloud property differences, in terms of optical depth; and LIG ocean circulation changes which occur for some, but not all, LIG simulations. Finally, we note that inter-comparisons between the LIG simulations and simulations for future climate with moderate (1 % yr−1) CO2 increase show a relationship between LIG sea ice and sea ice simulated under CO2 increase around the years of doubling CO2. The LIG may therefore yield insight into likely 21st century Arctic sea ice changes using these LIG simulations.
24 citations
09 Mar 2020
TL;DR: In this paper, the results from 12 climate models in terms of Arctic sea ice were compared in the 6th phase of the Coupled Model Intercomparison Project (CMIP) and the results showed that the mean pre-industrial to LIG reduction in minimum sea ice area (SIA) reached 59% (multi-model mean LIG area is 2.21 mill. km2, compared to 5.85 mill. mm km2 for the PI).
Abstract:
The Last interglacial (LIG) is a period with increased summer insolation at high northern latitudes, which results in strong changes in the terrestrial and marine cryosphere. Understanding the mechanisms for this response via climate modelling and comparing the models’ representation of climate reconstructions is one of the objectives set up by the Paleoclimate Modelling Intercomparison Project for its contribution to the sixth phase of the Coupled Model Intercomparison Project. Here we analyse the results from 12 climate models in terms of Arctic sea ice. The mean pre-industrial to LIG reduction in minimum sea ice area (SIA) reaches 59% (multi-model mean LIG area is 2.21 mill. km2, compared to 5.85 mill. km2 for the PI), and the range of model results for LIG minimum sea ice area (from 0.02 to 5.65 mill. km2) is larger than for PI (from 4.10 to 8.30 mill. km2). On the other hand there is little change for the maximum sea ice area (which is 12 mill. km2 for both the PI and the LIG, with a standard deviation of 1.04 mill. km2 for PI and 1.21 mill. km2 for LIG). To evaluate the model results we synthesize LIG sea ice data from marine cores collected in the Arctic Ocean, Nordic Seas and northern North Atlantic. South of 78oN, in the Atlantic and Nordic seas, the LIG was seasonally ice-free. North of 78oN there are some discrepancies between sea ice reconstructions based on dinocysts/foraminifers/ostracods and IP25: some sites have both seasonal and perennial interpretations based on the same core, but different indicators. Because of the conflicting interpretations it is not possible for any one model to match every data point in our data synthesis, or say whether the Arctic was seasonally ice-free. Drivers for the inter-model differences are: different phasing of the up and down short-wave anomalies over the Arctic ocean, associated with differences in model albedo; possible cloud property differences, in terms of optical depth; LIG ocean circulation changes which occur for some, but not all, LIG simulations. Finally we note that inter-comparisons between the LIG simulations, and simulations with moderate CO2 increase (during the transition to high CO2 levels), may yield insight into likely 21C Arctic sea ice changes using these LIG simulations.
19 citations
DOI•
18 Nov 2021
TL;DR: In this paper, a series of transient simulations of the penultimate deglaciation and last interglacial period was used to compare the results with a transient simulation of the Holocene and Holocene, and they found that the strengthening of the Atlantic Meridional Overturning Circulation at the end of deglacial millennial-scale events exerts a dominant control on the abrupt initiation of African Humid Periods as the Atlantic meridional overturning circulation modulates the position of the Intertropical Convergence Zone.
Abstract: During orbital precession minima, the Sahara was humid and more vegetated, providing potential corridors for Hominins migration. Uncertainties remain over the climatic processes controlling the initiation, demise and amplitude of these African Humid Periods. Here we study these processes using a series of transient simulations of the penultimate deglaciation and Last Interglacial period, and compare the results with a transient simulation of the last deglaciation and Holocene. We find that the strengthening of the Atlantic Meridional Overturning Circulation at the end of deglacial millennial-scale events exerts a dominant control on the abrupt initiation of African Humid Periods as the Atlantic Meridional Overturning Circulation modulates the position of the Intertropical Convergence Zone. In addition, residual Northern Hemispheric ice-sheets can delay the peak of the African Humid Period. Through its impact on Northern Hemispheric ice-sheets disintegration and thus Atlantic Meridional Overturning Circulation, the larger rate of insolation increase during the penultimate compared to the last deglaciation can explain the earlier and more abrupt onset of the African Humid Period during the Last Interglacial period. Finally, we show that the mean climate state modulates precipitation variability, with higher variability under wetter background conditions. A strengthening of the Atlantic Meridional Overturning Circulation was the main driver of the abrupt initiation of African Humid Periods during the last two deglaciations, according to transient simulations performed using an Earth system model.
10 citations
References
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TL;DR: HadISST1 as mentioned in this paper replaces the global sea ice and sea surface temperature (GISST) data sets and is a unique combination of monthly globally complete fields of SST and sea ice concentration on a 1° latitude-longitude grid from 1871.
Abstract: [1] We present the Met Office Hadley Centre's sea ice and sea surface temperature (SST) data set, HadISST1, and the nighttime marine air temperature (NMAT) data set, HadMAT1. HadISST1 replaces the global sea ice and sea surface temperature (GISST) data sets and is a unique combination of monthly globally complete fields of SST and sea ice concentration on a 1° latitude-longitude grid from 1871. The companion HadMAT1 runs monthly from 1856 on a 5° latitude-longitude grid and incorporates new corrections for the effect on NMAT of increasing deck (and hence measurement) heights. HadISST1 and HadMAT1 temperatures are reconstructed using a two-stage reduced-space optimal interpolation procedure, followed by superposition of quality-improved gridded observations onto the reconstructions to restore local detail. The sea ice fields are made more homogeneous by compensating satellite microwave-based sea ice concentrations for the impact of surface melt effects on retrievals in the Arctic and for algorithm deficiencies in the Antarctic and by making the historical in situ concentrations consistent with the satellite data. SSTs near sea ice are estimated using statistical relationships between SST and sea ice concentration. HadISST1 compares well with other published analyses, capturing trends in global, hemispheric, and regional SST well, containing SST fields with more uniform variance through time and better month-to-month persistence than those in GISST. HadMAT1 is more consistent with SST and with collocated land surface air temperatures than previous NMAT data sets.
8,958 citations
"Large-scale features of Last Interg..." refers methods in this paper
...Finally, temperature anomalies relative to the preindustrial period are calculated in both cases for marine sites using the HadISST dataset (Rayner et al., 2003), over the intervals 1870–1899 and 1870–1889 CE, in the compilations by Capron et al. (2017) and Hoffman et al. (2017), respectively....
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...S1) (Rayner et al., 2003)....
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TL;DR: The Global Precipitation Climatology Project (GPCP) version 2 Monthly Precise Analysis as discussed by the authors is a merged analysis that incorporates precipitation estimates from low-orbit satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations.
Abstract: The Global Precipitation Climatology Project (GPCP) Version 2 Monthly Precipitation Analysis is described. This globally complete, monthly analysis of surface precipitation at 2.5 degrees x 2.5 degrees latitude-longitude resolution is available from January 1979 to the present. It is a merged analysis that incorporates precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The merging approach utilizes the higher accuracy of the low-orbit microwave observations to calibrate, or adjust, the more frequent geosynchronous infrared observations. The data set is extended back into the premicrowave era (before 1987) by using infrared-only observations calibrated to the microwave-based analysis of the later years. The combined satellite-based product is adjusted by the raingauge analysis. This monthly analysis is the foundation for the GPCP suite of products including those at finer temporal resolution, satellite estimate, and error estimates for each field. The 23-year GPCP climatology is characterized, along with time and space variations of precipitation.
4,951 citations
"Large-scale features of Last Interg..." refers methods in this paper
...…CE; Compo et al., 2011) for the spatial patterns, zonal averages of observed temperature for the period 1850–1900 CE from the HadCRUT4 dataset (Morice et al., 2012; Ilyas et al., 2017), and climatological precipitation data for the period between 1970 and the present day (Adler et al., 2003)....
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TL;DR: A weekly 1° spatial resolution optimum interpolation (OI) sea surface temperature (SST) analysis has been produced at the National Oceanic and Atmospheric Administration (NOAA) using both in situ and satellite data from November 1981 to the present as mentioned in this paper.
Abstract: A weekly 1° spatial resolution optimum interpolation (OI) sea surface temperature (SST) analysis has been produced at the National Oceanic and Atmospheric Administration (NOAA) using both in situ and satellite data from November 1981 to the present. The weekly product has been available since 1993 and is widely used for weather and climate monitoring and forecasting. Errors in the satellite bias correction and the sea ice to SST conversion algorithm are discussed, and then an improved version of the OI analysis is developed. The changes result in a modest reduction in the satellite bias that leaves small global residual biases of roughly −0.03°C. The major improvement in the analysis occurs at high latitudes due to the new sea ice algorithm where local differences between the old and new analysis can exceed 1°C. Comparisons with other SST products are needed to determine the consistency of the OI. These comparisons show that the differences among products occur on large time- and space scales wit...
4,346 citations
Additional excerpts
...The monthly mean sea ice areas from the NOAA_OI_v2 dataset for 1982–2001 (Reynolds et al., 2002) are shown in panels (a) and (b)....
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TL;DR: In this article, the authors present the background and rationale for the new structure of CMIP, provides a detailed description of the DECK and CMIP6 historical simulations, and includes a brief introduction to the 21-CMIP6-Endorsed MIPs.
Abstract: . By coordinating the design and distribution of global climate model simulations of the past, current, and future climate, the Coupled Model Intercomparison Project (CMIP) has become one of the foundational elements of climate science. However, the need to address an ever-expanding range of scientific questions arising from more and more research communities has made it necessary to revise the organization of CMIP. After a long and wide community consultation, a new and more federated structure has been put in place. It consists of three major elements: (1) a handful of common experiments, the DECK (Diagnostic, Evaluation and Characterization of Klima) and CMIP historical simulations (1850–near present) that will maintain continuity and help document basic characteristics of models across different phases of CMIP; (2) common standards, coordination, infrastructure, and documentation that will facilitate the distribution of model outputs and the characterization of the model ensemble; and (3) an ensemble of CMIP-Endorsed Model Intercomparison Projects (MIPs) that will be specific to a particular phase of CMIP (now CMIP6) and that will build on the DECK and CMIP historical simulations to address a large range of specific questions and fill the scientific gaps of the previous CMIP phases. The DECK and CMIP historical simulations, together with the use of CMIP data standards, will be the entry cards for models participating in CMIP. Participation in CMIP6-Endorsed MIPs by individual modelling groups will be at their own discretion and will depend on their scientific interests and priorities. With the Grand Science Challenges of the World Climate Research Programme (WCRP) as its scientific backdrop, CMIP6 will address three broad questions: – How does the Earth system respond to forcing? – What are the origins and consequences of systematic model biases? – How can we assess future climate changes given internal climate variability, predictability, and uncertainties in scenarios? This CMIP6 overview paper presents the background and rationale for the new structure of CMIP, provides a detailed description of the DECK and CMIP6 historical simulations, and includes a brief introduction to the 21 CMIP6-Endorsed MIPs.
4,192 citations
TL;DR: In this article, new values for the astronomical parameters of the Earth's orbit and rotation (eccentricity, obliquity and precession) are proposed for paleoclimatic research related to the Late Miocene, the Pliocene and the Quaternary.
3,712 citations