Earth System Dynamics Discussions最新文献

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Rankings of extreme and widespread dry and wet events in the Iberian Peninsula between 1901 and 2016 1901年至2016年伊比利亚半岛极端和广泛的干湿事件排名
Earth System Dynamics Discussions Pub Date : 2021-02-19 DOI: 10.5194/ESD-12-197-2021
M. Liberato, I. Montero, C. Gouveia, A. Russo, A. Ramos, R. Trigo
{"title":"Rankings of extreme and widespread dry and wet events in the Iberian Peninsula between 1901 and 2016","authors":"M. Liberato, I. Montero, C. Gouveia, A. Russo, A. Ramos, R. Trigo","doi":"10.5194/ESD-12-197-2021","DOIUrl":"https://doi.org/10.5194/ESD-12-197-2021","url":null,"abstract":"Abstract. Extensive, long-standing dry and wet episodes are two of\u0000the most frequent climatic extreme events in the Iberian Peninsula. Here, a\u0000method for ranking regional extremes of persistent, widespread drought and\u0000wet events is presented, considering different timescales. The method is\u0000based on the multi-scalar Standardized Precipitation Evapotranspiration Index\u0000(SPEI) gridded dataset for the Iberian Peninsula. Climatic Research Unit\u0000(CRU) data are used to compute the SPEI between 1901 and 2016 by means of a\u0000log-logistic probability distribution function. The potential\u0000evapotranspiration (PET) is computed using the Penman–Monteith equation.\u0000The ranking classification method is based on the assessment of the\u0000magnitude of an event, which is obtained after considering both the area affected by the respective dryness or wetness – defined by SPEI values over a\u0000certain threshold – and its intensity in each grid point. A sensitivity\u0000analysis of the impact of different thresholds used to define dry and wet events\u0000is also performed. For both the dry and wet periods, this simple yet robust tool\u0000allows for the identification and ranking of well-known regional extremes of persistent,\u0000extensive dry and wet periods at different timescales. A comprehensive\u0000dataset of rankings of the most extreme, prolonged, widespread dry and wet\u0000periods in the Iberian Peninsula is presented for aggregated timescales of\u00006, 12, 18, and 24 months. Results show that no region in the Iberian Peninsula is more prone to the occurrence of any of these long-term (dry\u0000and/or wet) extreme events. Finally, it is highlighted that the\u0000application of this methodology to other domains and periods represents an\u0000important tool for extensive, long-standing, extreme event assessment\u0000worldwide.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"12 1","pages":"197-210"},"PeriodicalIF":0.0,"publicationDate":"2021-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84911525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Trivial improvements of predictive skill due to direct reconstructionof global carbon cycle 由于全球碳循环的直接重建,预测技能的微小改进
Earth System Dynamics Discussions Pub Date : 2021-02-18 DOI: 10.5194/ESD-2021-4
A. Spring, I. Dunkl, Hongmei Li, V. Brovkin, T. Ilyina
{"title":"Trivial improvements of predictive skill due to direct reconstruction\u0000of global carbon cycle","authors":"A. Spring, I. Dunkl, Hongmei Li, V. Brovkin, T. Ilyina","doi":"10.5194/ESD-2021-4","DOIUrl":"https://doi.org/10.5194/ESD-2021-4","url":null,"abstract":"Abstract. State-of-the-art carbon cycle prediction systems are initialized from reconstruction simulations in which state variables of the climate system are assimilated. While currently only the physical state variables are assimilated, biogeochemical state variables adjust to the state acquired through this assimilation indirectly instead of being assimilated themselves. In the absence of comprehensive biogeochemical reanalysis products, such approach is pragmatic. Here we evaluate a potential advantage of having perfect carbon cycle observational products to be used for direct carbon cycle reconstruction. Within an idealized perfect-model framework, we define 50 years of a control simulation under pre-industrial CO2 levels as our target representing observations. We nudge variables from this target onto arbitrary initial conditions 150 years later mimicking an assimilation simulation generating initial conditions for hindcast experiments of prediction systems. We investigate the tracking performance, i.e. bias, correlation and root-mean-square-error between the reconstruction and the target, when nudging an increasing set of atmospheric, oceanic and terrestrial variables with a focus on the global carbon cycle explaining variations in atmospheric CO2. We compare indirect versus direct carbon cycle reconstruction against a resampled threshold representing internal variability. Afterwards, we use these reconstructions to initialize ensembles to assess how well the target can be predicted after reconstruction. Interested in the ability to reconstruct global atmospheric CO2, we focus on the global carbon cycle reconstruction and predictive skill. We find that indirect carbon cycle reconstruction through physical fields reproduces the target variations on a global and regional scale much better than the resampled threshold. While reproducing the large scale variations, nudging introduces systematic regional biases in the physical state variables, on which biogeochemical cycles react very sensitively. Global annual surface oceanic pCO2 initial conditions are indirectly reconstructed with an anomaly correlation coefficient (ACC) of 0.8 and debiased root mean square error (RMSE) of 0.3 ppm. Direct reconstruction slightly improves initial conditions in ACC by +0.1 and debiased RMSE by −0.1 ppm. Indirect reconstruction of global terrestrial carbon cycle initial conditions for vegetation carbon pools track the target by ACC of 0.5 and debiased RMSE of 0.5 PgC. Direct reconstruction brings negligible improvements for air-land CO2 flux. Global atmospheric CO2 is indirectly tracked by ACC of 0.8 and debiased RMSE of 0.4 ppm. Direct reconstruction of the marine and terrestrial carbon cycles improves ACC by 0.1 and debiased RMSE by −0.1 ppm. We find improvements in global carbon cycle predictive skill from direct reconstruction compared to indirect reconstruction. After correcting for mean bias, indirect and direct reconstruction both predict the target simil","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"110 1","pages":"1-36"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79545538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Assessment of a full-field initialized decadal climate prediction system with the CMIP6 version of EC-Earth 基于CMIP6版本EC-Earth的全场初始化年代际气候预测系统评价
Earth System Dynamics Discussions Pub Date : 2021-02-11 DOI: 10.5194/ESD-12-173-2021
R. Bilbao, S. Wild, P. Ortega, Juan Acosta-Navarro, T. Arsouze, P. Bretonnière, L. Caron, M. Castrillo, Rubén Cruz-García, I. Cvijanovic, F. Doblas-Reyes, M. Donat, E. Dutra, P. Echevarria, A. Ho, Saskia Loosveldt-Tomas, E. Moreno‐Chamarro, N. Pérez-Zañón, A. Ramos, Y. Ruprich‐Robert, V. Sicardi, É. Tourigny, Javier Vegas-Regidor
{"title":"Assessment of a full-field initialized decadal climate prediction system with the CMIP6 version of EC-Earth","authors":"R. Bilbao, S. Wild, P. Ortega, Juan Acosta-Navarro, T. Arsouze, P. Bretonnière, L. Caron, M. Castrillo, Rubén Cruz-García, I. Cvijanovic, F. Doblas-Reyes, M. Donat, E. Dutra, P. Echevarria, A. Ho, Saskia Loosveldt-Tomas, E. Moreno‐Chamarro, N. Pérez-Zañón, A. Ramos, Y. Ruprich‐Robert, V. Sicardi, É. Tourigny, Javier Vegas-Regidor","doi":"10.5194/ESD-12-173-2021","DOIUrl":"https://doi.org/10.5194/ESD-12-173-2021","url":null,"abstract":"Abstract. In this paper, we present and evaluate the skill of an EC-Earth3.3 decadal prediction system contributing to the Decadal Climate Prediction Project – Component A (DCPP-A). This prediction system is capable of skilfully simulating past global mean surface temperature variations at interannual and decadal forecast times as well as the local surface temperature in regions such as the tropical Atlantic, the Indian Ocean and most of the continental areas, although most of the skill comes from the representation of the external radiative forcings. A benefit of initialization in the predictive skill is evident in some areas of the tropical Pacific and North Atlantic oceans in the first forecast years, an added value that is mostly confined to the south-east tropical Pacific and the eastern subpolar North Atlantic at the longest forecast times (6–10 years). The central subpolar North Atlantic shows poor predictive skill and a detrimental effect of initialization that leads to a quick collapse in Labrador Sea convection, followed by a weakening of the Atlantic Meridional Overturning Circulation (AMOC) and excessive local sea ice growth. The shutdown in Labrador Sea convection responds to a gradual increase in the local density stratification in the first years of the forecast, ultimately related to the different paces at which surface and subsurface temperature and salinity drift towards their preferred mean state. This transition happens rapidly at the surface and more slowly in the subsurface, where, by the 10th forecast year, the model is still far from the typical mean states in the corresponding ensemble of historical simulations with EC-Earth3. Thus, our study highlights the Labrador Sea as a region that can be sensitive to full-field initialization and hamper the final prediction skill, a problem that can be alleviated by improving the regional model biases through model development and by identifying more optimal initialization strategies.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"194 1","pages":"173-196"},"PeriodicalIF":0.0,"publicationDate":"2021-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83092540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 35
On structural errors in emergent constraints 论紧急约束中的结构误差
Earth System Dynamics Discussions Pub Date : 2021-02-10 DOI: 10.5194/ESD-2020-85
B. Sanderson, A. Pendergrass, C. Koven, F. Brient, B. Booth, R. Fisher, R. Knutti
{"title":"On structural errors in emergent constraints","authors":"B. Sanderson, A. Pendergrass, C. Koven, F. Brient, B. Booth, R. Fisher, R. Knutti","doi":"10.5194/ESD-2020-85","DOIUrl":"https://doi.org/10.5194/ESD-2020-85","url":null,"abstract":"Abstract. Studies of emergent constraints have frequently proposed that a single metric alone can constrain future responses of the Earth system to anthropogenic emissions. The prevalence of this thinking has led to literature and messaging which is sometimes confusing to policymakers, with a series of studies over the last decade making confident, yet contradictory, claims on the probability bounds of key climate variables. Here, we illustrate that emergent constraints are more likely to occur where the variance across an ensemble of climate models of both observable and future climate arises from common structural assumptions and few degrees of freedom. Such cases are likely to occur when processes are represented in a common, oversimplified fashion throughout the ensemble, about which we have the least confidence in performance out of sample. We consider these issues in the context of a number of published constraints, and argue that the application of emergent constraints alone to estimate uncertainties in unknown climate responses can potentially lead to bias and overconfidence in constrained projections. Together with statistical robustness and plausibility of mechanism, assessments of climate responses must include multiple lines of evidence to identify biases that arise from common oversimplified modeling assumptions which impact both present and future climate simulations in order to mitigate against the influence of common structural biases.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"30 1","pages":"1-30"},"PeriodicalIF":0.0,"publicationDate":"2021-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85553691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Characterisation of Atlantic meridional overturning hysteresis using Langevin dynamics 用朗之万动力学表征大西洋经向翻转迟滞
Earth System Dynamics Discussions Pub Date : 2021-01-18 DOI: 10.5194/ESD-12-69-2021
J. van den Berk, S. Drijfhout, W. Hazeleger
{"title":"Characterisation of Atlantic meridional overturning hysteresis using Langevin dynamics","authors":"J. van den Berk, S. Drijfhout, W. Hazeleger","doi":"10.5194/ESD-12-69-2021","DOIUrl":"https://doi.org/10.5194/ESD-12-69-2021","url":null,"abstract":"Abstract. Hysteresis diagrams of the Atlantic meridional overturning circulation (AMOC) under freshwater forcing from climate models of intermediate complexity are fitted to a simple model based on the Langevin equation.\u0000A total of six parameters are sufficient to quantitatively describe the collapses seen in these simulations.\u0000Reversing the freshwater forcing results in asymmetric behaviour that is less well captured and appears to require a more complicated model.\u0000The Langevin model allows for comparison between models that display an AMOC collapse. Differences between the climate models studied here are mainly due to the strength of the stable AMOC and the strength of the response to a freshwater forcing.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"14 1","pages":"69-81"},"PeriodicalIF":0.0,"publicationDate":"2021-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75124462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Stratospheric ozone and quasi-biennial oscillation (QBO) interaction with the tropical troposphere on intraseasonal and interannual timescales: a normal-mode perspective 平流层臭氧和准两年生振荡(QBO)与热带对流层在季节内和年际时间尺度上的相互作用:正态模态视角
Earth System Dynamics Discussions Pub Date : 2021-01-18 DOI: 10.5194/ESD-12-83-2021
B. Raphaldini, Andre S. W. Teruya, Pedro Leite da Silva Dias, L. Massaroppe, D. Y. Takahashi
{"title":"Stratospheric ozone and quasi-biennial oscillation (QBO) interaction with the tropical troposphere on intraseasonal and interannual timescales: a normal-mode perspective","authors":"B. Raphaldini, Andre S. W. Teruya, Pedro Leite da Silva Dias, L. Massaroppe, D. Y. Takahashi","doi":"10.5194/ESD-12-83-2021","DOIUrl":"https://doi.org/10.5194/ESD-12-83-2021","url":null,"abstract":"Abstract. The Madden–Julian oscillation (MJO) is the main controller of the weather in\u0000the tropics on intraseasonal timescales, and recent research provides\u0000evidence that the quasi-biennial oscillation (QBO) influences the MJO\u0000interannual variability. However, the physical mechanisms behind this\u0000interaction are not completely understood. Recent studies on the normal-mode\u0000structure of the MJO indicate the contribution of global-scale Kelvin and\u0000Rossby waves. In this study we test whether these MJO-related normal modes are\u0000affected by the QBO and stratospheric ozone. The partial directed coherence\u0000method was used and enabled us to probe the direction and frequency of the\u0000interactions. It was found that equatorial stratospheric ozone and\u0000stratospheric zonal winds are connected with the MJO at periods of 1–2 months\u0000and 1.5–2.5 years. We explore the role of normal-mode interactions behind the\u0000stratosphere–troposphere coupling by performing a linear regression between\u0000the MJO–QBO indices and the amplitudes of the normal modes of the atmosphere\u0000obtained by projections on a normal-mode basis using ERA-Interim reanalysis\u0000data. The MJO is dominated by symmetric Rossby modes but is also influenced by\u0000Kelvin and asymmetric Rossby modes. The QBO is mostly explained by westward-propagating inertio-gravity waves and asymmetric Rossby waves. We explore the\u0000previous results by identifying interactions between those modes and between\u0000the modes and the ozone concentration. In particular, westward inertio-gravity\u0000waves, associated with the QBO, influence the MJO on interannual\u0000timescales. MJO-related modes, such as Kelvin waves and Rossby waves\u0000with a symmetric wind structure with respect to the Equator, are shown to have\u0000significantly different dynamics during MJO events depending on the phase of\u0000the QBO.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"1 1","pages":"83-101"},"PeriodicalIF":0.0,"publicationDate":"2021-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83681361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 7
ESD Ideas: The Peclet number is a cornerstone of the orbital and millennial Pleistocene variability ESD观点:佩莱特数是轨道和千禧年更新世变化的基石
Earth System Dynamics Discussions Pub Date : 2021-01-12 DOI: 10.5194/ESD-12-63-2021
M. Verbitsky, M. Crucifix
{"title":"ESD Ideas: The Peclet number is a cornerstone of the orbital and millennial Pleistocene variability","authors":"M. Verbitsky, M. Crucifix","doi":"10.5194/ESD-12-63-2021","DOIUrl":"https://doi.org/10.5194/ESD-12-63-2021","url":null,"abstract":"Abstract. We demonstrate here that a single physical phenomenon, specifically, a\u0000naturally changing balance between intensities of temperature advection and\u0000diffusion in the viscous ice media, may influence the entire spectrum of the\u0000Pleistocene variability from orbital to millennial timescales.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"1 1","pages":"63-67"},"PeriodicalIF":0.0,"publicationDate":"2021-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82123093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Net land-use change carbon flux estimates and sensitivities – Anassessment with a bookkeeping model based on CMIP6 forcing 土地利用净变化碳通量估算和敏感性——基于CMIP6强迫的簿记模式的评估
Earth System Dynamics Discussions Pub Date : 2021-01-11 DOI: 10.5194/ESD-2020-94
K. Hartung, A. Bastos, L. Chini, R. Ganzenmüller, Felix Havermann, G. Hurtt, T. Loughran, J. Nabel, Tobias B. Nützel, W. Obermeier, J. Pongratz
{"title":"Net land-use change carbon flux estimates and sensitivities – An\u0000assessment with a bookkeeping model based on CMIP6 forcing","authors":"K. Hartung, A. Bastos, L. Chini, R. Ganzenmüller, Felix Havermann, G. Hurtt, T. Loughran, J. Nabel, Tobias B. Nützel, W. Obermeier, J. Pongratz","doi":"10.5194/ESD-2020-94","DOIUrl":"https://doi.org/10.5194/ESD-2020-94","url":null,"abstract":"Abstract. The carbon flux due to land-use and land-cover change (net LULCC flux) historically contributed to a large fraction of anthropogenic carbon emissions while at the same time being associated with large uncertainties. This study aims to compare the contribution of several sensitivities underlying the net LULCC flux by assessing their relative importance in a bookkeeping model (BLUE) based on a LULCC dataset including uncertainty estimates (the LUH2 dataset). The sensitivity experiments build upon the approach of Hurtt et al. (2011) and compare the impacts of LULCC uncertainty (a high, baseline and low land- use estimate), the starting time of the bookkeeping model simulation (850, 1700 and 1850), net area transitions versus gross area transitions (shifting cultivation) and neglecting wood harvest on estimates of the net LULCC flux. Additional factorial experiments isolate the impact of uncertainty from initial conditions and transitions on the net LULCC flux. Finally, historical simulations are extended with future land-use scenarios to assess the impact of past LULCC uncertainty in future projections. Over the period 1850–2014, baseline and low LULCC scenarios produce a comparable cumulative net LULCC flux while the high LULCC estimate initially produces a larger net LULCC flux which decreases towards the end of the period and even becomes smaller than in the baseline estimate. LULCC uncertainty leads to slightly higher sensitivity in the cumulative net LULCC flux (up to 22 %, reference are the baseline simulations) compared to the starting year of a model simulation (up to 15 %). The contribution from neglecting wood harvest activities (up to 28 % cumulative net LULCC flux) is larger than from LULCC uncertainty and the implementation of land-cover transitions (gross or net transitions) exhibits the smallest sensitivity (up to 13 %). At the end of the historical LULCC dataset in 2014, the LULCC uncertainty retains some impact on the net LULCC flux (±0.15 PgC yr−1 at an estimate of 1.7 PgC yr−1). Of the past uncertainties in LULCC, a small impact persists in 2099, mainly due to uncertainty of harvest remaining in 2014. However, compared to the uncertainty range of the LULCC flux estimated today, the estimates in 2099 appear to be indistinguishable. These results, albeit from a single model, are important for CMIP6 as they compare the relative importance of starting year, uncertainty of LULCC, applying gross transitions and wood harvest on the net LULCC flux. For the cumulative net LULCC flux over the industrial period the uncertainty of LULCC is as relevant as applying wood harvest and gross transitions. However, LULCC uncertainty matters less (by about a factor three) than the other two factors for the net LULCC flux in 2014 and historical LULCC uncertainty is negligible for estimates of future scenarios.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"13 1","pages":"1-34"},"PeriodicalIF":0.0,"publicationDate":"2021-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78854774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Dating hiatuses: a statistical model of the recent slowdown in global warming and the next one 断续期:最近全球变暖减缓的统计模型和下一个模型
Earth System Dynamics Discussions Pub Date : 2020-12-11 DOI: 10.5194/ESD-11-1123-2020
J. Miller, K. Nam
{"title":"Dating hiatuses: a statistical model of the recent slowdown in global warming and the next one","authors":"J. Miller, K. Nam","doi":"10.5194/ESD-11-1123-2020","DOIUrl":"https://doi.org/10.5194/ESD-11-1123-2020","url":null,"abstract":"Abstract. Much has been written about the so-called hiatus or pause in global warming, also known as the stasis period, the start of which is typically dated to 1998. HadCRUT4 global mean temperatures slightly decreased over 1998–2013, though a simple statistical model predicts that they should have grown by 0.016 °C/yr, in proportion to the increases in concentrations of well-mixed greenhouse gases and ozone. We employ a statistical approach to assess the contributions of model forcings and natural variability to the hiatus. We find that none of the model forcings explain more than a fifth of the missing heat and that the El Nino Southern Oscillation (ENSO) explains at least half and possibly more than four fifths of the missing heat. Looking forward, the simple model also fails to explain the large increases since then (0.087 °C/year over 2013–2016). This period coincides with another El Nino, but the ENSO fails to satisfactorily account for the increase. We propose instead a semiparametric cointegrating statistical model that augments an energy balance model with a novel multibasin measure of the oceans' multidecadal temperatures cycles. The model partially explains the recent slowdown and explains nearly all of the subsequent warming. The natural cycle suggests the possibility of a much longer hiatus over roughly 2023–2061, with rather important policy implications.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"12 1","pages":"1123-1132"},"PeriodicalIF":0.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85213109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
The extremely warm summer of 2018 in Sweden – set in a historical context 2018年瑞典极端温暖的夏天——以历史背景为背景
Earth System Dynamics Discussions Pub Date : 2020-12-07 DOI: 10.5194/ESD-11-1107-2020
R. Wilcke, E. Kjellström, Changgui Lin, D. Matei, A. Moberg, E. Tyrlis
{"title":"The extremely warm summer of 2018 in Sweden – set in a historical context","authors":"R. Wilcke, E. Kjellström, Changgui Lin, D. Matei, A. Moberg, E. Tyrlis","doi":"10.5194/ESD-11-1107-2020","DOIUrl":"https://doi.org/10.5194/ESD-11-1107-2020","url":null,"abstract":"Abstract. Two long-lasting high pressure systems in summer 2018 lead to long lasting heat waves over Scandinavia and other parts of Europe and an extended summer period with devastating impacts on agriculture, infrastructure and human life. We use five climate model ensembles and the unique 263 year long Stockholm temperature time series along with a composite 150 year long time series for whole Sweden to set the latest heat-wave in summer 2018 in historical perspective. With 263 years we are able to grasp the pre-industrial time well and see a clear upward trend in temperature itself as well as heat wave indicators. With five climate model ensembles providing 20 580 simulated summers representing the latest 70 years, we analyse the likelihood of such a heat event and how unusual the 2018 Swedish summer actually was. We find that conditions as those observed in summer 2018 show up in all climate model ensembles. An exception is the monthly mean temperature for May for which 2018 was warmer than any member in one of the five climate model ensembles. However, even if the ensembles generally hold individual years like 2018, the comparison shows that such conditions are rare. For the indices assessed here, anomalies such as observed in 2018 occur maximally in 5 % of the ensemble members, sometimes even in less than 1 %. For all indices evaluated we find that probabilities of a summer like in 2018 have increased from relatively low values for the one ensemble extending back to 1861–90 and for all five ensembles including 1951–80 to the most recent decades (1989–2018). An implication is that anthropogenic climate change has strongly increased the probability of a warm summer such as the one observed 2018 to occur in Sweden. Despite this, we still find such summers also in the pre-industrial climate, however, with a lower probability.","PeriodicalId":11466,"journal":{"name":"Earth System Dynamics Discussions","volume":"1 1","pages":"1107-1121"},"PeriodicalIF":0.0,"publicationDate":"2020-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90841014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 27
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