第四次国际古气候模拟比较计划（PMIP4）概况与评述

古气候模拟比较计划（PMIP）是古气候数值模拟领域一项重大的国际合作研究计划,其主旨是为古气候模拟和模拟结果评估提供一个协调机制,理解过去气候变化的物理机制和气候反馈的重要作用,为未来气候预估提供科学依据。同时,通过对比分析验证模式的模拟性能,探索其不确定性,促进耦合气候系统模式的发展。PMIP目前进行到第四阶段（PMIP4)。PMIP4进一步加强了与第六次国际耦合模式比较计划（CMIP6）的协作,选取了5组共同关注的PMIP4-CMIP6古气候模拟试验（中全新世、末次盛冰期、过去千年、末次间冰期和上新世暖期),考察气候系统对不同气候背景的综合响应。除此以外,PMIP4还设计了众多敏感性试验研究不同外强迫因子的影响。PMIP4模拟试验不仅为古气候研究提供大量的模拟数据,还将服务于CMIP6及其他众多模式比较计划。     

Revisiting Mid-Holocene Temperature over China Using PMIP3 Simulations

Using the simulations performed by 15 cli mate models under the latest protocol of the Paleoclimate Modeling Intercomparison Project(PMIP)Phase 3(PMIP3),the authors revisited the annual and seasona temperature changes over China during the mid-Holocene Similar to the previous results produced by PMIP Phase 1(PMIP1)and 2(PMIP2)models,14(15)of the 15 PMIP3models reproduced colder annual(boreal winter and spring)temperature in response to mid-Holocene insola tion changes,with an average cooling of 0.33 K(1.31 K and 1.58 K)over China.The mid-Holocene boreal sum mer(autumn)temperature increased in all(13)of the 15PMIP3 models,with an average warming of 1.02 K(0.61K)at the national scale.Those changes simulated by the PMIP3 models were similar to those from the PMIP2simulations but generally weaker than those from the PMIP1 models.A considerable mismatch still existed between the simulated cooling by the PMIP3 models and the reconstructed warming for annual and winter tem peratures over China during the mid-Holocene,as wa also the case between the previous PMIP1/2 simulation and proxy data.     

Past and future polar amplification of climate change: climate model intercomparisons and ice-core constraints

Climate model simulations available from the PMIP1, PMIP2 and CMIP (IPCC-AR4) intercomparison projects for past and future climate change simulations are examined in terms of polar temperature changes in comparison to global temperature changes and with respect to pre-industrial reference simulations. For the mid-Holocene (MH, 6,000 years ago), the models are forced by changes in the Earth’s orbital parameters. The MH PMIP1 atmosphere-only simulations conducted with sea surface temperatures fixed to modern conditions show no MH consistent response for the poles, whereas the new PMIP2 coupled atmosphere–ocean climate models systematically simulate a significant MH warming both for Greenland (but smaller than ice-core based estimates) and Antarctica (consistent with the range of ice-core based range). In both PMIP1 and PMIP2, the MH annual mean changes in global temperature are negligible, consistent with the MH orbital forcing. The simulated last glacial maximum (LGM, 21,000 years ago) to pre-industrial change in global mean temperature ranges between 3 and 7°C in PMIP1 and PMIP2 model runs, similar to the range of temperature change expected from a quadrupling of atmospheric CO₂ concentrations in the CMIP simulations. Both LGM and future climate simulations are associated with a polar amplification of climate change. The range of glacial polar amplification in Greenland is strongly dependent on the ice sheet elevation changes prescribed to the climate models. All PMIP2 simulations systematically underestimate the reconstructed glacial–interglacial Greenland temperature change, while some of the simulations do capture the reconstructed glacial–interglacial Antarctic temperature change. Uncertainties in the prescribed central ice cap elevation cannot account for the temperature change underestimation by climate models. The variety of climate model sensitivities enables the exploration of the relative changes in polar temperature with respect to changes in global temperatures. Simulated changes of polar temperatures are strongly related to changes in simulated global temperatures for both future and LGM climates, confirming that ice-core-based reconstructions provide quantitative insights on global climate changes. An erratum to this article can be found at     

CAS-ESM2.0 Model Datasets for the CMIP6 Flux-Anomaly-Forced Model Intercomparison Project(FAFMIP)

The second version of the Chinese Academy of Sciences Earth System Model(CAS-ESM2.0)is participating in the Flux-Anomaly-Forced Model Intercomparison Project(FAFMIP)experiments in phase 6 of the Coupled Model Intercomparison Project(CMIP6).The purpose of FAFMIP is to understand and reduce the uncertainty of ocean climate changes in response to increased CO2 forcing in atmosphere-ocean general circulation models(AOGCMs),including the simulations of ocean heat content(OHC)change,ocean circulation change,and sea level rise due to thermal expansion.FAFMIP experiments(including faf-heat,faf-stress,faf-water,faf-all,faf-passiveheat,faf-heat-NA50pct and faf-heat-NA0pct)have been conducted.All of the experiments were integrated over a 70-year period and the corresponding data have been uploaded to the Earth System Grid Federation data server for CMIP6 users to download.This paper describes the experimental design and model datasets and evaluates the preliminary results of CAS-ESM2.0 simulations of ocean climate changes in the FAFMIP experiments.The simulations of the changes in global ocean temperature,Atlantic Meridional Overturning Circulation(AMOC),OHC,and dynamic sea level(DSL),are all reasonably reproduced.     

NUIST ESM v3 Data Submission to CMIP6

This paper introduces the experimental designs and outputs of the Diagnostic,Evaluation and Characterization of Klima(DECK),historical,Scenario Model Intercomparison Project(MIP),and Paleoclimate MIP(PMIP)experiments from the Nanjing University of Information Science and Technology Earth System Model version 3(NESM3).Results show that NESM3 reasonably simulates the modern climate and the major internal modes of climate variability.In the Scenario MIP experiment,changes in the projected surface air temperature(SAT)show robust“Northern Hemisphere(NH)warmer than Southern Hemisphere(SH)”and“land warmer than ocean”patterns,as well as an El Ni?o-like warming over the tropical Pacific.Changes in the projected precipitation exhibit“NH wetter than SH”and“eastern hemisphere gets wetter and western hemisphere gets drier”patterns over the tropics.These precipitation patterns are driven by circulation changes owing to the inhomogeneous warming patterns.Two PMIP experiments show enlarged seasonal cycles of SAT and precipitation over the NH due to the seasonal redistribution of solar radiation.Changes in the climatological mean SAT,precipitation,and ENSO amplitudes are consistent with the results from PMIP4 models.The NESM3 outputs are available on the Earth System Grid Federation nodes for data users.     

FGOALS-g3 Model Datasets for CMIP6 Flux-Anomaly-Forced Model Intercomparison Project

The Flux-Anomaly-Forced Model Intercomparison Project(FAFMIP) is an endorsed Model Intercomparison Project in phase 6 of the Coupled Model Intercomparison Project(CMIP6). The goal of FAFMIP is to investigate the spread in the atmosphere–ocean general circulation model projections of ocean climate change forced by increased CO_2, including the uncertainties in the simulations of ocean heat uptake, global mean sea level rise due to ocean thermal expansion and dynamic sea level change due to ocean circulation and density changes. The FAFMIP experiments have already been conducted with the Flexible Global Ocean–Atmosphere–Land System Model, gridpoint version 3.0(FGOALS-g3). The model datasets have been submitted to the Earth System Grid Federation(ESGF) node. Here, the details of the experiments,the output variables and some baseline results are presented. Compared with the preliminary results of other models, the evolutions of global mean variables can be reproduced well by FGOALS-g3. The simulations of spatial patterns are also consistent with those of other models in most regions except the North Atlantic and the Southern Ocean, indicating large uncertainties in the regional sea level projections of these two regions.     

Mid-Holocene climate in Europe: what can we infer from PMIP model-data comparisons?

 Within the framework of the PMIP (Paleoclimate Modelling Intercomparison Project), we have compared mid-Holocene climate simulations from 16 atmospheric general circulation models (AGCMs) with new pollen-based reconstructions of the European bioclimatic variables for winter and growing season temperatures as well as annual water budget changes. In winter, some models are able to simulate the reconstructed northeastern warming, due to an increased heat transport from the ocean, associated with a larger north-south pressure gradient over the northern Atlantic. Whereas most models are only able to simulate a strong summer warming, data indicate a shorter and/ or colder growing season in southern Europe and a longer and/or warmer growing season in northwestern Europe. The reconstructed change in annual water budget indicates drier conditions in northwestern Europe and wetter conditions in southern Europe. Some models simulate such moisture changes, due to more summer evaporation over Scandinavia during summer, and more autumn-winter-spring precipitation over southern Europe. To address the PMIP approximation of no change in ocean and land boundary conditions, we have performed short sensitivity experiments to surface boundary conditions (sea-surface-temperatures, vegetation) using one single model. The model-data disagreements over Europe are probably due to the local influence of the surrounding oceans which are not taken into account in the first PMIP simulations. We therefore stress the need for more mid-Holocene SST reconstructions and further analysis of pollen data in the Mediterranean region. Received: 23 February 1998 /Accepted: 19 September 1998     

The Southern Annular Mode (SAM) in PMIP2 simulations of the last glacial maximum

The increasing trend of the Southern Annular Mode （SAM） in recent decades has influenced climate change in the Southem Hemisphere （SH）.How the SAM will respond increased greenhouse gas concentrations in the future remains uncertain.Understanding the variability of the SAM in the past under a colder climate such as during the Last Glacial Maximum （LGM） might provide some understanding of the response of the SAM under a future warmer climate.We analyzed the changes in the SAM during the LGM in comparison to pre-industrial （PI） simulations using five coupled ocean-atmosphere models （CCSM,FGOALS,IPSL,MIROC,HadCM） from the second phase of the Paleoclimate Modelling Intercomparison Project （PMIP2）.In CCSM,MIROC,IPSL,and FGOALS,the variability of the simulated SAM appears to be reduced in the LGM compared to the PI simulations,with a decrease in the standard deviation of the SAM index.Overall,four out of the five models suggest a weaker SAM amplitude in the LGM consistent with a weaker SH polar vortex and westerly winds found in some proxy records and model analyses.The weakening of the SAM in the LGM was associated with an increase in the vertical propagation of Rossby waves in southern high latitudes.     

基于PMIP3和CMIP5模拟结果的过去千年特征时段北极涛动的变率特征及成因分析

利用参与第三次古气候模式评估比较计划（Paleoclimate Modelling Intercomparison Project Phase III,PMIP3）过去千年气候模拟试验以及参与第五次耦合模式评估比较计划（Paleoclimate Model Intercomparison Project Phase 5,CMIP5）全强迫历史情景试验的9个地球系统模式模拟试验结果,对过去千年3个特征时段（中世纪气候异常期、小冰期和现代暖期）北极涛动（Arctic Oscillation, AO）的变率及成因进行了分析。通过与NCEP再分析资料的对比发现,模式能够较好地模拟出AO的空间模态及年际变化周期,且大部分模式能够模拟出过去50年AO的增强趋势。过去千年3个特征时段中,不同模式对中世纪气候异常期AO位相的模拟并不一致,但大部分模式显示小冰期AO基本呈现负位相,而现代暖期则表现为显著的正位相,与重建结果一致。基于多模式集合平均的机制分析表明,中世纪气候异常期北极地区海平面气压变化不显著,小冰期北极地区海平面气压显著偏正,现代暖期海平面气压显著偏负,这与现代暖期北极温度偏高而小冰期北极温度偏低有关。过去千年中,小冰期和现代暖期的AO变率分别受自然外强迫和人为外强迫的影响。     

ENSO at 6ka and 21ka from ocean–atmosphere coupled model simulations

We analyze how the characteristics of El Niño-Southern Oscillation (ENSO) are changed in coupled ocean–atmosphere simulations of the mid-Holocene (MH) and the Last Glacial Maximum (LGM) performed as part of the Paleoclimate Modeling Intercomparison Project phase 2 (PMIP2). Comparison of the model results with present day observations show that most of the models reproduce the large scale features of the tropical Pacific like the SST gradient, the mean SST and the mean seasonal cycles. All models simulate the ENSO variability, although with different skill. Our analyses show that several relationships between El Niño amplitude and the mean state across the different control simulations are still valid for simulations of the MH and the LGM. Results for the MH show a consistent El Niño amplitude decrease. It can be related to the large scale atmospheric circulation changes. While the Northern Hemisphere receives more insolation during the summer time, the Asian summer monsoon system is strengthened which leads to the enhancement of the Walker circulation. Easterlies prevailing over the central eastern Pacific induce an equatorial upwelling that damps the El Niño development. Results are less conclusive for 21ka. Large scale dynamic competes with changes in local heat fluxes, so that model shows a wide range of responses, as it is the case in future climate projections.     

我国对末次冰期冰盛期东亚区域气候模拟的研究

末次冰期冰盛期（或称为末次盛冰期）,为第四纪更新世最后一个冰期的鼎盛时期,该时期的气候与当代气候迥然不同。近年来,中国科研工作者已就末次冰期冰盛期东亚区域气候开展了一些数值模拟工作。结果表明：该时期中国大陆地表气温降低,中东部地区降水显著减少,东亚冬季风增强、夏季风显著减弱。在国际古气候模拟比较计划（PMIP）标准试验的基础上,进一步指出东亚植被的反馈作用、青藏高原可能冰川的反馈作用、以及西太平洋表面温度的作用能够引起额外的气候效应,可在一定程度上改进PMIP标准试验的模拟效果。     

Maintenance of PDO variability during the mid-holocene in PMIP2

Using the Paleoclimate Modeling Intercomparison Project Phase 2 (PMIP2), we investigate Pacific Decadal Oscillation (PDO) variability during the Mid-Holocene (6,000 years ago), especially maintenance of the PDO variability during the mid-Holocene despite reduced El Nino-Southern Oscillation (ENSO) activity. Most of the models participating PMIP2 identified the reduced ENSO activity during the mid-Holocene, but essentially little difference in PDO variability between the pre-industrial and mid-Holocene periods. Through multiple regression and partial correlation analysis, we found that the influence of the ENSO on the PDO was reduced due to reduced ENSO activity, but that the influence of local atmospheric circulation (Aleutian Low; AL) was enhanced during the mid-Holocene even though the variability of AL itself did not change much between the mid-Holocene and the present. That is, the reduction in PDO activity due to the weaken ENSO is offset by the enhanced PDO attributable to the intensified influence of the AL. As a result, the PDO variability during the mid-Holocene was as active as that during the pre-industrial era.     

A comparison of PMIP2 model simulations and the MARGO proxy reconstruction for tropical sea surface temperatures at last glacial maximum

Results from multiple model simulations are used to understand the tropical sea surface temperature (SST) response to the reduced greenhouse gas concentrations and large continental ice sheets of the last glacial maximum (LGM). We present LGM simulations from the Paleoclimate Modelling Intercomparison Project, Phase 2 (PMIP2) and compare these simulations to proxy data collated and harmonized within the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface Project (MARGO). Five atmosphere–ocean coupled climate models (AOGCMs) and one coupled model of intermediate complexity have PMIP2 ocean results available for LGM. The models give a range of tropical (defined for this paper as 15°S–15°N) SST cooling of 1.0–2.4°C, comparable to the MARGO estimate of annual cooling of 1.7 ± 1°C. The models simulate greater SST cooling in the tropical Atlantic than tropical Pacific, but interbasin and intrabasin variations of cooling are much smaller than those found in the MARGO reconstruction. The simulated tropical coolings are relatively insensitive to season, a feature also present in the MARGO transferred-based estimates calculated from planktonic foraminiferal assemblages for the Indian and Pacific Oceans. These assemblages indicate seasonality in cooling in the Atlantic basin, with greater cooling in northern summer than northern winter, not captured by the model simulations. Biases in the simulations of the tropical upwelling and thermocline found in the preindustrial control simulations remain for the LGM simulations and are partly responsible for the more homogeneous spatial and temporal LGM tropical cooling simulated by the models. The PMIP2 LGM simulations give estimates for the climate sensitivity parameter of 0.67°–0.83°C per Wm⁻², which translates to equilibrium climate sensitivity for doubling of atmospheric CO₂ of 2.6–3.1°C.     

BCC-ESM1 Model Datasets for the CMIP6 Aerosol Chemistry Model Intercomparison Project(AerChemMIP)

BCC-ESM1 is the first version of the Beijing Climate Center’s Earth System Model,and is participating in phase 6 of the Coupled Model Intercomparison Project(CMIP6).The Aerosol Chemistry Model Intercomparison Project(AerChemMIP)is the only CMIP6-endorsed MIP in which BCC-ESM1 is involved.All AerChemMIP experiments in priority 1 and seven experiments in priorities 2 and 3 have been conducted.The DECK(Diagnostic,Evaluation and Characterization of Klima)and CMIP historical simulations have also been run as the entry card of CMIP6.The AerChemMIP outputs from BCC-ESM1 have been widely used in recent atmospheric chemistry studies.To facilitate the use of the BCC-ESM1 datasets,this study describes the experiment settings and summarizes the model outputs in detail.Preliminary evaluations of BCC-ESM1 are also presented,revealing that:the climate sensitivities of BCC-ESM1 are well within the likely ranges suggested by IPCC AR5;the spatial structures of annual mean surface air temperature and precipitation can be reasonably captured,despite some common precipitation biases as in CMIP5 and CMIP6 models;a spurious cooling bias from the 1960s to 1990s is evident in BCC-ESM1,as in most other ESMs;and the mean states of surface sulfate concentrations can also be reasonably reproduced,as well as their temporal evolution at regional scales.These datasets have been archived on the Earth System Grid Federation(ESGF)node for atmospheric chemistry studies.     

Tropical paleoclimates at the Last Glacial Maximum: comparison of Paleoclimate Modeling Intercomparison Project (PMIP) simulations and paleodata

 Seventeen simulations of the Last Glacial Maximum (LGM) climate have been performed using atmospheric general circulation models (AGCM) in the framework of the Paleoclimate Modeling Intercomparison Project (PMIP). These simulations use the boundary conditions for CO₂, insolation and ice-sheets; surface temperatures (SSTs) are either (a) prescribed using CLIMAP data set (eight models) or (b) computed by coupling the AGCM with a slab ocean (nine models). The present-day (PD) tropical climate is correctly depicted by all the models, except the coarser resolution models, and the simulated geographical distribution of annual mean temperature is in good agreement with climatology. Tropical cooling at the LGM is less than at middle and high latitudes, but greatly exceeds the PD temperature variability. The LGM simulations with prescribed SSTs underestimate the observed temperature changes except over equatorial Africa where the models produce a temperature decrease consistent with the data. Our results confirm previous analyses showing that CLIMAP (1981) SSTs only produce a weak terrestrial cooling. When SSTs are computed, the models depict a cooling over the Pacific and Indian oceans in contrast with CLIMAP and most models produce cooler temperatures over land. Moreover four of the nine simulations, produce a cooling in good agreement with terrestrial data. Two of these model results over ocean are consistent with new SST reconstructions whereas two models simulate a homogeneous cooling. Finally, the LGM aridity inferred for most of the tropics from the data, is globally reproduced by the models with a strong underestimation for models using computed SSTs. Received: 9 September 1998 / Accepted: 18 March 1999     

Mid-Holocene and last glacial maximum climate simulations with the IPSL model: part II: model-data comparisons

The climates of the mid-Holocene (MH, 6,000 years ago) and the Last Glacial Maximum (LGM, 21,000 years ago) have been extensively documented and as such, have become targets for the evaluation of climate models for climate contexts very different from the present. In Part 1 of the present work, we have studied the MH and LGM simulations performed with the last two versions of the IPSL model: IPSL_CM4, run for the PMIP2/CMIP3 (Coupled Model Intercomparion Project) projects and IPSL_CM5A, run for the most recent PMIP3/CMIP5 projets. We have shown that not only are these models different in their simulations of the PI climate, but also in their simulations of the climatic anomalies for the MH and LGM. In the Part 2 of this paper, we first examine whether palaeo-data can help discriminate between the model performances. This is indeed the case for the African monsoon for the MH or for North America south of the Laurentide ice sheet, the South Atlantic or the southern Indian ocean for the LGM. For the LGM, off-line vegetation modelling appears to offer good opportunities to distinguish climate model results because glacial vegetation proves to be very sensitive to even small differences in LGM climate. For other cases such as the LGM North Atlantic or the LGM equatorial Pacific, the large uncertainty on the SST reconstructions, prevents model discrimination. We have examined the use of other proxy-data for model evaluation, which has become possible with the inclusion of the biogeochemistry morel PISCES in the IPSL_CM5A model. We show a broad agreement of the LGM–PI export production changes with reconstructions. These changes are related to the mixed layer depth in most regions and to sea-ice variations in the high latitudes. We have also modelled foraminifer abundances with the FORAMCLIM model and shown that the changes in foraminifer abundance in the equatorial Pacific are mainly forced by changes in SSTs, hence confirming the SST-foraminifer abundance relationship. Yet, this is not the case in all regions in the North Atlantic, where food availability can have a strong impact of foraminifer abundances. Further work will be needed to exhaustively examine the role of factors other than climate in piloting changes in palaeo-indicators.     

Climate model benchmarking with glacial and mid-Holocene climates

Past climates provide a test of models’ ability to predict climate change. We present a comprehensive evaluation of state-of-the-art models against Last Glacial Maximum and mid-Holocene climates, using reconstructions of land and ocean climates and simulations from the Palaeoclimate Modelling and Coupled Modelling Intercomparison Projects. Newer models do not perform better than earlier versions despite higher resolution and complexity. Differences in climate sensitivity only weakly account for differences in model performance. In the glacial, models consistently underestimate land cooling (especially in winter) and overestimate ocean surface cooling (especially in the tropics). In the mid-Holocene, models generally underestimate the precipitation increase in the northern monsoon regions, and overestimate summer warming in central Eurasia. Models generally capture large-scale gradients of climate change but have more limited ability to reproduce spatial patterns. Despite these common biases, some models perform better than others.     

Overview of the CMIP6 Historical Experiment Datasets with the Climate System Model CAS FGOALS-f3-L

The three-member historical simulations by the Chinese Academy of Sciences Flexible Global Ocean–Atmosphere–Land System model, version f3-L(CAS FGOALS-f3-L), which is contributing to phase 6 of the Coupled Model Intercomparison Project(CMIP6), are described in this study. The details of the CAS FGOALS-f3-L model, experiment settings and output datasets are briefly introduced. The datasets include monthly and daily outputs from the atmospheric, oceanic, land and sea-ice component models of CAS FGOALS-f3-L, and all these data have been published online in the Earth System Grid Federation(ESGF, https://esgf-node.llnl.gov/projects/cmip6/). The three ensembles are initialized from the 600th, 650th and 700th model year of the preindustrial experiment(piControl) and forced by the same historical forcing provided by CMIP6 from 1850 to 2014. The performance of the coupled model is validated in comparison with some recent observed atmospheric and oceanic datasets. It is shown that CAS FGOALS-f3-L is able to reproduce the main features of the modern climate, including the climatology of air surface temperature and precipitation,the long-term changes in global mean surface air temperature, ocean heat content and sea surface steric height, and the horizontal and vertical distribution of temperature in the ocean and atmosphere. Meanwhile, like other state-of-the-art coupled GCMs, there are still some obvious biases in the historical simulations, which are also illustrated. This paper can help users to better understand the advantages and biases of the model and the datasets.     

The Last Glacial Maximum climate over Europe and western Siberia: a PMIP comparison between models and data

 Under the framework of the Palaeoclimate Modelling Intercomparison Project (PMIP), 17 climate models, 16 of which are atmospheric general circulation models, have been run to simulate the climate of the Last Glacial Maximum (21 000 years ago) using the same set of boundary conditions. Parallel to these numerical experiments, new, consistent, data bases have been developed on a continental scale. The present work compares the range of the model responses to the large perturbation corresponding to the conditions of the Last Glacial Maximum with consistently derived climate reconstructions from pollen records over Europe and western Siberia. It accounts for the differences in the model results due to the models themselves and directly compares this “error bar” due to the models to the uncertainties in the climate reconstructions from the pollen records. Overall the Last Glacial Maximum climate simulated by the models over western Europe is warmer, especially in winter, and wetter than the one depicted by the reconstructions. This is the region where the reconstructed increase in temperature, precipitation and moisture index from the Last Glacial Maximum to the present conditions is largest. The same disagreement, but of smaller amplitude, is found over Central Europe and the eastern Mediterranean Basin, while models and data are in broad agreement over western Siberia. The numerous modelling results allow a study of the link between the changes in atmospheric circulation and those in temperature, and an interpretation of the discrepancies in precipitation in terms of those in temperature. Received: 1 February 2000 / Accepted: 9 May 2000