scholarly journals Assessing mean climate change signals in the global CORDEX-CORE ensemble

Author(s):  
Claas Teichmann ◽  
Daniela Jacob ◽  
Armelle Reca Remedio ◽  
Erika Coppola ◽  

<p>The Coordinated Output for Regional Evaluations (CORE) simulation ensemble is an effort of the WCRP CORDEX community to provide high-resolution regional climate change information for the major inhabited areas of the world and thus generate a solid scientific basis for further research related vulnerability, impact, adaptation and climate services. This is especially important in those areas in which only a few high-resolution simulations or only comparatively coarse simulations from global models were available. The driving global climate model (GCM) simulations were selected to cover the spread of high, medium, and low equilibrium climate sensitivity at a global scale. Initially, two regional climate models (RCMs) REMO and RegCM4 were used to downscale GCM output to a spatial resolution of 0.22°. It is intended that the CORDEX-CORE ensemble can then be extended by additional regional simulations to further increase the ensemble size and thus the representation of possible future climate change pathways. </p><p>The aim of this study is to investigate and document the climate change information provided by the current CORDEX-CORE ensemble with respect to the mean climate change in different regions of the world and in comparison to previously existing global climate information, especially those global climate simulations used as boundary forcing for CORDEX-CORE RCMs. First, the regional biases of the RCMs simulations and its driving GCMs simulations were quantified compared to the CRU TS 4.02 observational dataset during the reference period from 1971 to 2000. Second, the near future (2036 to 2065) and far future (2071 to 2099) climate change signals were quantified from the new CORDEX-CORE ensemble. The analysis focuses on the mean temperature and precipitation changes based on the new IPCC physical climate reference regions. For selected regions, the differences of the climate change information at different resolutions are documented. Using this selected regions, the climate change signals from the CORDEX-CORE ensemble were compared to other existing CORDEX simulations and the CMIP5 GCM ensemble. First results of this comparison will be presented.</p>

2020 ◽  
Author(s):  
Claas Teichmann ◽  
Daniela Jacob ◽  
Armelle Reca Remedio ◽  
Thomas Remke ◽  
Lars Buntemeyer ◽  
...  

<p>The Coordinated Output for Regional Evaluations (CORE) simulation ensemble is an effort of the WCRP CORDEX community to provide high resolution regional climate change information for the major inhabited areas of the world and thus to generate the solid scientific basis for further research related to vulnerability, impact, adaptation and climate services (VIACS). This is especially important in those areas in which so far only few high-resolution simulations or only global comparatively coarse simulations were available. The driving simulations were selected to cover the spread of high, medium and low climate sensitivity at a global scale. Initially, the two RCMs REMO and RegCM4 were used to downscale these data global climate model output to a resolution of 0.22° (about 25km) while it is intended that the CORDEX CORE ensemble can then be extended by additional regional simulations to further increase the ensemble size and thus the representation of possible future climate change pathways.</p> <p>The aim of this study is to investigate and document the climate change information provided by the current CORDEX CORE ensemble with respect to mean climate change in different regions and in comparison to previously existing global climate information, especially those global climate simulations used as boundary forcing for CORDEX CORE, but also in comparison to the entire AR5-GCM ensemble. The analysis focuses on the representation of the AR5-GCM range of climate change signals by the CORDEX CORE ensemble with respect to mean temperature and precipitation changes and corresponding shifts in the annual cycles in the new AR6 IPCC physical reference regions. This also provides an indication for CORDEX CORE suitability for VIACS applications in each region.</p>


2020 ◽  
Author(s):  
Claas Teichmann ◽  
Daniela Jacob ◽  
Armelle Reca Remedio ◽  
Thomas Remke ◽  
Lars Buntemeyer ◽  
...  

Abstract The new Coordinated Output for Regional Evaluations (CORDEX-CORE) ensemble provides high-resolution, consistent regional climate change projections for the major inhabited areas of the world. It serves as a solid scientific basis for further research related to vulnerability, impact, adaptation and climate services in addition to existing CORDEX simulations. The aim of this study is to investigate and document the climate change information provided by the CORDEX-CORE simulation ensemble, as a part of the World Climate Research Programme (WCRP) CORDEX community. An overview of the annual and monthly mean climate change information in selected regions in different CORDEX domains is presented for temperature and precipitation, providing the foundation for detailed follow-up studies and applications. Initially, two regional climate models (RCMs), REMO and RegCM were used to downscale global climate model output. The driving simulations by AR5 global climate models (AR5-GCMs) were selected to cover the spread of high, medium, and low equilibrium climate sensitivity at a global scale. The CORDEX-CORE ensemble has doubled the spatial resolution compared to the previously existing CORDEX simulations in most of the regions (25$$\,\mathrm {km}$$ km (0.22$$^{\circ }$$ ∘ ) versus 50$$\,\mathrm {km}$$ km (0.44$$^{\circ }$$ ∘ )) leading to a potentially improved representation of, e.g., physical processes in the RCMs. The analysis focuses on changes in the IPCC physical climate reference regions. The results show a general reasonable representation of the spread of the temperature and precipitation climate change signals of the AR5-GCMs by the CORDEX-CORE simulations in the investigated regions in all CORDEX domains by mostly covering the AR5 interquartile range of climate change signals. The simulated CORDEX-CORE monthly climate change signals mostly follow the AR5-GCMs, although for specific regions they show a different change in the course of the year compared to the AR5-GCMs, especially for RCP8.5, which needs to be investigated further in region specific process studies.


2017 ◽  
pp. 42-52
Author(s):  
Debasis Poddar

Hindu Kush Himalayan region (hereafter the HKH) - with 3500 odd kilometres stretched in eight countries- is default resource generation hub for about one-fifth population of the world. The ecosystem-growing delicate these days- seems to play a critical role for the survival of flora and fauna along with the maintenance of all its life-sustaining mountain glaciers. Ten major rivers to carry forward hitherto sustainable development of these peoples fall into question now. Further, in the wake of global climate change today, the delicate HKH ecosystem becomes increasingly fragile to unfold manifold consequences and thereby take its toll on the population. And the same might turn apocalyptic in its magnanimity of irreversibledamage. Like time-bomb, thus, climate ticks to get blown off. As it is getting already too delayed for timely resort to safeguards, if still not taken care of in time, lawmakers ought to find the aftermath too late to lament for. Besides being conscious for climate discipline across the world, collective efforts on the part of all regional states together are imperative to minimize the damage. Therefore, each one has put hands together to be saved from the doomsday that appears to stand ahead to accelerate a catastrophicend, in the given speed of global climate change. As the largest Himalayan state and its central positioning at the top of the HKH, Nepal has had potential to play a criticalrole to engage regional climate change regime and thereby spearhead climate diplomacy worldwide to play regional capital of the HKH ecosystem. As regional superpower, India has had potential to usurp leadership avatar to this end. With reasoningof his own, the author pleads for better jurisprudence to attain regional environmental integrity inter se- rather than regional environmental integration alone- to defendthe vulnerable HKH ecosystem since the same constitutes common concern of humankind and much more so for themselves. Hence, to quote from Shakespeare, “To be or not to be, that is the question” is reasonable here. While states are engaged in the spree to cause mutually agreed destruction, global climate change- with deadly aftermath- poses the last and final unifier for them to turn United Nations in rhetoric sense o f the term.


2001 ◽  
Vol 41 (1) ◽  
pp. 689
Author(s):  
C.D. Mitchell ◽  
G.I. Pearman

The prospect of global-scale changes in climate resulting from changes in atmospheric greenhouse gas concentrations has produced a complex set of public and private- sector responses. This paper reviews several elements of this issue that are likely to be most important to industry.Scientific research continues to provide evidence to suggest that global climate will change significantly over the coming decades due to increases in the atmospheric concentration of greenhouse gases. Nonetheless, there exists a debate over the difference between observations of temperature retrieved from satellite and temperature measurements taken from the surface. Recent research undertaken to inform the debate is discussed, with the conclusion that there are real differences in trend between the surface and the lower atmosphere that can be explained in physical terms. Attention is turning to developing an understanding as to why climate model results show apparently consistent trends between the surface and the lower atmosphere, in contrast to these observations.While such uncertainties in the underlying science have been used to question whether action on the greenhouse issues is necessary, the initial response, as evidenced by international negotiations, has been to start mitigating greenhouse gas emissions. Adaptation to future climate change has received less attention than mitigation. A number of reasons for this are discussed, including the fact that regional scenarios of climate change are uncertain.The principles of risk management may be one way to manage the uncertainties associated with projections of regional climate change. Although the application of risk management to the potential impacts of climate change requires further investigation, elements of such a framework are identified, and include:Identifying the critical climate-related thresholds that are important to industry and its operations (for example, a 1-in-100 year return tropical cyclone).Using this understanding to analyse, and where possible quantify, industry’s pre-existing or baseline adaptive state through the use of sensitivity surfaces and quantified thresholds (for example, were facilities designed for a 1-in-100 event or a 1-in-500 year event?)Establishing probabilistic statements or scenarios of climate that are relevant to industry practice (for example, risk of a storm surge may be more important to operations than elevated wind strength; if so, what is the probability that an event will exceed the design threshold during the lifetime of the facility?).Bringing information on existing adaptive mechanisms together with climate scenarios to produce a quantitative risk assessment.Deciding on risk treatment (additional adaptive measures).


2021 ◽  
Author(s):  
Qifen Yuan ◽  
Thordis L. Thorarinsdottir ◽  
Stein Beldring ◽  
Wai Kwok Wong ◽  
Chong-Yu Xu

Abstract. Climate change impact assessment related to floods, infrastructure networks and water resources management applications requires realistic simulations of high-resolution gridded precipitation series under a future climate. This paper proposes to produce such simulations by combining a weather generator for high-resolution gridded daily precipitation, trained on historical observation-based gridded data product, with coarser scale climate change information obtained using a regional climate model. The climate change information can be added to various components of the weather generator, related to both the probability of precipitation as well as the amount of precipitation on wet days. The information is added in a transparent manner, allowing for an assessment of the plausibility of the added information. In a case study of nine hydrological catchments in central Norway with the study areas covering 1000–5500 km2, daily simulations are obtained on a 1 km grid for a period of 19 years. The method yields simulations with realistic temporal and spatial structures and outperforms empirical quantile delta mapping in terms of marginal performance.


2020 ◽  
Author(s):  
Gerald Lim ◽  
Aurel Moise ◽  
Raizan Rahmat ◽  
Bertrand Timbal

<p>Southeast Asia (SEA) is a rapidly developing and densely populated region that is home to over 600 million people. This, together with the region’s high sensitivity, exposure and low adaptive capacities, makes it particularly vulnerable to climate change and extremes such as floods, droughts and tropical cyclones. While the last decade saw some countries in SEA develop their own climate change projections, studies were largely uncoordinated and most countries still lack the capability to independently produce robust future climate information. Following a proposal from the World Meteorological Organisation (WMO) Regional Association (RA) V working group on climate services, the ASEAN Regional Climate Data, Analysis and Projections (ARCDAP) workshop series was conceived in 2017 to bridge these gaps in regional synergies. The ARCDAP series has been organised annually since 2018 by the ASEAN Specialised Meteorological Centre (hosted by Meteorological Service Singapore) with support from WMO through the Canada-funded Climate Risk and Early Warning Systems (Canada-CREWS) initiative.</p><p>This presentation will cover the activities and outcomes from the first two workshops, as well as the third which will be held in February 2020. The ARCDAP series has so far brought together representatives from ASEAN National Meteorological and Hydrological Services (NMHSs), climate scientists and end-users from policy-making and a variety of vulnerability and impact assessment (VIA) sectors, to discuss and identify best practices regarding the delivery of climate change information, data usage and management, advancing the science etc. Notable outputs include two comprehensive workshop reports and a significant regional contribution to the HadEX3 global land in-situ-based dataset of temperature and precipitation extremes, motivated by work done with the ClimPACT2 software.</p><p>The upcoming third workshop will endeavour to encourage the uptake of the latest ensemble of climate simulations from the Coupled Model Intercomparison Project (CMIP6) using CMIP-endorsed tools such as ESMValTool. This will address the need for ASEAN climate change practitioners to upgrade their knowledge of the latest global climate model database. It is anticipated that with continued support from WMO, the series will continue with the Fourth workshop targeting the assessment of downscaling experiments in 2021.</p>


2020 ◽  
Author(s):  
Sabina Abba-Omar ◽  
Francesca Raffaele ◽  
Erika Coppola ◽  
Daniela Jacob ◽  
Claas Teichmann ◽  
...  

<p>CORDEX-CORE is a new phase of CORDEX simulations with higher resolutions (0.22 degrees) consisting of two RCMs forced by three GCMs. This higher resolution ensemble could provide added value to regional climate change information, however, since the data has just recently been released, more studies are required to validate and report on its climate change signal. With this in mind, we computed the mean climate and extreme indices over Africa using the CORDEX-CORE ensemble. These results are compared to the results of  the driving models as well as to the lower resolution CORDEX-phase 1 ensemble. We found that for most of the extreme indices the CORDEX-CORE shows lower biases over Africa owing to its higher spatial resolution. We also found that the mean climate change signal over Africa was broadly consistent across the three different ensembles. Indicating that the new CORDEX-CORE ensemble is able to capture the uncertainty spread well. We report the projected changes in extreme indices over Africa found in the new higher resolution CORDEX-CORE ensemble. We also examine and compare the representation of some key dynamical features over Africa in the different ensembles. Africa is especially vulnerable to extreme events, due to its limited capacity for disaster management. Thus, this study adds important, higher resolution information to the existing climate change impact knowledge for Africa. </p><p><br><br></p>


2014 ◽  
Vol 27 (14) ◽  
pp. 5259-5284 ◽  
Author(s):  
Xiuquan Wang ◽  
Guohe Huang ◽  
Qianguo Lin ◽  
Jinliang Liu

Abstract Planning of mitigation and adaptation strategies to a changing climate can benefit from a good understanding of climate change impacts on human life and local society, which leads to an increasing requirement for reliable projections of future climate change at regional scales. This paper presents an ensemble of high-resolution regional climate simulations for the province of Ontario, Canada, developed with the Providing Regional Climates for Impacts Studies (PRECIS) modeling system. A Bayesian statistical model is proposed through an advance to the method proposed by Tebaldi et al. for generating probabilistic projections of temperature changes at gridpoint scale by treating the unknown quantities of interest as random variables to quantify their uncertainties in a statistical way. Observations for present climate and simulations from the ensemble are fed into the statistical model to derive posterior distributions of all the uncertain quantities through a Markov chain Monte Carlo (MCMC) sampling algorithm. Detailed analyses at 12 selected weather stations are conducted to investigate the practical significance of the proposed statistical model. Following that, maps of projected temperature changes at different probability levels are presented to help understand the spatial patterns across the entire province. The analysis shows that there is likely to be a significant warming trend throughout the twenty-first century. It also suggests that people in Ontario are very likely to suffer a change greater than 2°C to mean temperature in the forthcoming decades and very unlikely to suffer a change greater than 10°C to the end of this century.


2020 ◽  
Author(s):  
Jesús Fernández ◽  
María Dolores Frías

<p>International model intercomparison initiatives, such as CORDEX or CMIP5, along with several relatively recent projects at international and national level, provide a wealth of model simulations of future regional climate. In a recent work, Fernandez et al (2019) collected 196 different future climate change projections over Spain, considering data from ENSEMBLES, ESCENA, EURO- and Med-CORDEX, along with their driving global climate projections from CMIP3 and CMIP5. This ensemble mixed different multi-model initiatives in an ensemble of opportunity, in the sense that it does not respond to any scientific design beyond the exploration of multi-model uncertainty. This ensemble of opportunity is not only the result of the mixture of different initiatives, but also responds to the lack of a balanced experimental design within most of the initiatives. Many of the initiatives -especially those unfunded, such as CORDEX- are carried out on a voluntary basis, with no strong constraint in the global climate models (GCMs) used as boundary conditions or in the number of contributing members per regional climate model (RCM).</p><p>Fernandez et al (2019) found in this ensemble a strong influence of the driving GCM on the regional climate change signal, along with favored GCMs, selected by many regional climate modelling groups to the detriment of GCMs publishing their output later or not at all. In this work, we quantitatively assess the impact of unbalanced GCM-RCM ensembles. For this purpose, we subsampled the ensemble of opportunity to obtain balanced sets of members according to different “what-if” situations: What if all RCMs had contributed a single member to the ensemble? What if each GCM had been dynamically downscaled only once? What if a given GCM/RCM had not contributed to the ensemble? For each hypothesis, there are a number of alternative sub-ensembles, which are used to evaluate uncertainty.</p><p><strong>Acknowledgement:</strong></p><p>This work is partially funded by the Spanish government through MINECO/FEDER co-funded projects INSIGNIA (CGL2016-79210-R) and MULTI-SDM (CGL2015-66583-R). </p><p><strong>References:</strong></p><p>Fernández, J., et al. (2019) Consistency of climate change projections from multiple global and regional model intercomparison projects. Clim Dyn 52:1139. https://doi.org/10.1007/s00382-018-4181-8</p>


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