Search

The PRIMAVERA project aimed to develop a new generation of advanced and well-evaluated high-resolution global climate models. As part of PRIMAVERA, seven different climate models were run in both standard and higher resolution configurations, with common initial conditions and forcings to form a multi-model ensemble. The ensemble simulations were run on high performance computers across Europe and generated approximately 1.6 pebibytes of output. To allow the data from all models to be analysed at this scale, PRIMAVERA scientists were encouraged to bring their analysis to the data. All data was transferred to a Central Analysis Facility (CAF), in this case the JASMIN super-data-cluster, where it was catalogued and details made available to users using the PRIMAVERA Data Management Tool's (DMT's) web interface. Users from across the project were able to query the available data using the DMT and then access it at the CAF. Here we describe how the PRIMAVERA project used the CAF's facilities to enable users to analyse this multi-model data set. We believe that PRIMAVERA's experience using a CAF demonstrates how similar, multi institute, big-data projects can efficiently share, organise and analyse large volumes of data.

North Atlantic sea surface temperatures (SSTs) underwent pronounced multidecadal variability during the twentieth and early twenty-first century. We examine the impacts of this Atlantic Multidecadal Variability (AMV), also referred to as the Atlantic Multidecadal Oscillation (AMO), on climate in an ensemble of five coupled climate models at both low and high spatial resolution. We use a SST nudging scheme specified by the Coupled Model Intercomparision Project’s Decadal Climate Prediction Project Component C (CMIP6 DCPP-C) to impose a persistent positive/negative phase of the AMV in the North Atlantic in coupled model simulations; SSTs are free to evolve outside this region. The large-scale seasonal mean response to the positive AMV involves widespread warming over Eurasia and the Americas, with a pattern of cooling over the Pacific Ocean similar to the Pacific Decadal Oscillation (PDO), together with a northward displacement of the inter-tropical convergence zone (ITCZ). The accompanying changes in global atmospheric circulation lead to widespread changes in precipitation. We use Analysis of Variance (ANOVA) to demonstrate that this large-scale climate response is accompanied by significant differences between models in how they respond to the common AMV forcing, particularly in the tropics. These differences may arise from variations in North Atlantic air-sea heat fluxes between models despite a common North Atlantic SST forcing pattern. We cannot detect a widespread effect of increased model horizontal resolution in this climate response, with the exception of the ITCZ, which shifts further northwards in the positive phase of the AMV in the higher resolution configurations. The Authors would like to acknowledge the use of the UKRI funded JASMIN data analysis facility which was essential to the analysis and storage of PRIMAVERA project data. Ongoing curation of project data has been supported by the IS-ENES3 project that has received funding from the European Union’ Horizon 2020 research and innovation programme under Grant Agreement No. 824084. Authors DH, PM, JS, PD, YRR, CDR acknowledge funding from the PRIMAVERA project (www.primavera-h2020.eu), funded by the European Union’s Horizon 2020 programme under Grant Agreement 641727. PM was supported by U.K.–China Research and Innovation Partnership Fund through the Met Office Climate Science for Service Partnership (CSSP) China as part of the Newton Fund. PD thanks ECMWF for providing computing time in the framework of the special projects SPITDAVI. YRR was funded by the European Union’s Horizon 2020 Research and Inovation Programme in the framework of the Marie Skłodowska-Curie grant INADEC (Grant Agreement 80015400). Author DH would like to thank Nick Klingaman and Linda Hirons for their extensive help with the MetUM-GOML model. This article was written with support (DH) from National Environmental Research Council (NERC) national capability grant for the North Atlantic Climate System: Integrated study (ACSIS) program (Grants NE/N018001/1, NE/N018044/1, NE/N018028/1, and NE/N018052/1). MMR is supported by a Juan de la Cierva Incorporacion research contract of MICINN (Spain). The authors wish to acknowledge use of the Ferret program for analysis and graphics in this paper. Ferret is a product of NOAA’s Pacific Marine Environmental Laboratory. (Information is available at http://ferret.pmel.noaa.gov/Ferret/) and also the CF-python analysis package http://ncas-cms.github.io/cf-python/. Assembly of MetUM-GOML and development of MC-KPP was supported by the National Centre for Atmospheric Science and led by Dr. Nicholas Klingaman. The authors would also like to thank the three anonymous reviewers whose comments contributed to a much improved final manuscript. Peer Reviewed "Article signat per 17 autors/es: Daniel L. R. Hodson, Pierre-Antoine Bretonnière, Christophe Cassou, Paolo Davini, Nicholas P. Klingaman, Katja Lohmann, Jorge Lopez-Parages, Marta Martín-Rey, Marie-Pierre Moine, Paul-Arthur Monerie, Dian A. Putrasahan, Christopher D. Roberts, Jon Robson, Yohan Ruprich-Robert, Emilia Sanchez-Gomez, Jon Seddon & Retish Senan"

In the North Atlantic, approximately half of tropical cyclones undergo extratropical transition, and landfalling systems pose risks to populous midlatitude regions. The frequency of tropical-origin storms across the midlatitudes is projected to increase under anthropogenic climate change, but multi-model studies are required to help reduce uncertainties. One key uncertainty is the role of Atlantic multidecadal variability (AMV), a robust understanding of which will help contextualise projections. We assess the impacts AMV+ and AMV– on basin-wide tropical cyclone and extratropical transition activity in an ensemble of coupled sensitivity experiments from CMIP6 HighResMIP. We used objective methods—a Lagrangian feature-tracking algorithm and cyclone phase-space analysis—to identify tropical cyclones undergoing extratropical transition and present analysis of changes in cyclogenesis, tracks, and intensity in response to AMV forcing.

This study investigates tropical cyclone integrated kinetic energy, a measure which takes into account the intensity and the size of the storms and which is closely associated with their damage potential, in three different global climate models integrated following the HighResMIP protocol. In particular, the impact of horizontal resolution and of the ocean coupling are assessed. We find that, while the increase in resolution results in smaller and more intense storms, the integrated kinetic energy of individual cyclones remains relatively similar between the two configurations. On the other hand, atmosphere‐ocean coupling tends to reduce the size and the intensity of the storms, resulting in lower integrated kinetic energy in that configuration. Comparing cyclone integrated kinetic energy between a present and a future scenario did not reveal significant differences between the two periods. This research has been supported by the Horizon 2020 programme (PRIMAVERA, GA #641727). S. Wild received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska- Curie grant agreement 2020-MSCA- COFUND-2016-754433 and financial support from the Spanish Agencia Estatal de Investigación (FJC2019- 041186-I/AEI/10.13039/501100011033). M. J. Roberts acknowledges the support from the UK-China Research and Innovation Partnership Fund through the Met Office Climate Science for Service Partnership (CSSP) China as part of the Newton Fund. Finally, the authors are most grateful to three anonymous reviewers for their helpful comments in improving a previous version of this manuscript.

A dominant paradigm for mid-latitude air-sea interaction identifies the synoptic-scale atmospheric “noise” as the main driver for the observed ocean surface variability. While this conceptual model successfully holds over most of the mid-latitude ocean surface, its soundness over frontal zones (including western boundary currents; WBC) characterized by intense mesoscale activity, has been questioned in a number of studies suggesting a driving role for the small scale ocean dynamics (mesoscale oceanic eddies) in the modulation of air-sea interaction. In this context, climate models provide a powerful experimental device to inspect the emerging scale-dependent nature of mid-latitude air-sea interaction. This study assesses the impact of model resolution on the representation of air-sea interaction over the Gulf Stream region, in a multi-model ensemble of present-climate simulations performed using a common experimental design. Lead-lag correlation and covariance patterns between sea surface temperature (SST) and turbulent heat flux (THF) are diagnosed to identify the leading regimes of air-sea interaction in a region encompassing both the Gulf Stream system and the North Atlantic subtropical basin. Based on these statistical metrics it is found that coupled models based on “laminar” (eddy-parameterised) and eddy-permitting oceans are able to discriminate between an ocean-driven regime, dominating the region controlled by the Gulf Stream dynamics, and an atmosphere-driven regime, typical of the open ocean regions. However, the increase of model resolution leads to a better representation of SST and THF cross-covariance patterns and functional forms, and the major improvements can be largely ascribed to a refinement of the oceanic model component. The authors of this study wish to thank two reviewers for their many insightful comments. AB, PA, ES, RH, JG-S, DP, ESG, MJR, CR, JS, PV acknowledge PRIMAVERA funding received from the European Commission under Grant Agreement 641727 of the Horizon 2020 research programme. JG-S was additionally supported by the Spanish ‘Ramón y Cajal’ programme (RYC-2016-21181). The authors declare that they have no conflict of interest. The datasets used in this work are cited in this manuscript with appropriate doi’s in publicly available archives.

Future changes in tropical cyclone properties are an important component of climate change impacts and risk for many tropical and midlatitude countries. In this study we assess the performance of a multimodel ensemble of climate models, at resolutions ranging from 250 to 25 km. We use a common experimental design including both atmosphere‐only and coupled simulations run over the period 1950–2050, with two tracking algorithms applied uniformly across the models. There are overall improvements in tropical cyclone frequency, spatial distribution, and intensity in models at 25 km resolution, with several of them able to represent very intense storms. Projected tropical cyclone activity by 2050 generally declines in the South Indian Ocean, while changes in other ocean basins are more uncertain and sensitive to both tracking algorithm and imposed forcings. Coupled models with smaller biases suggest a slight increase in average TC 10 m wind speeds by 2050., Key Points Biases in tropical cyclone distribution, frequency, and intensity are generally reduced in models at 25 km resolutionNorthern Hemisphere basins show mixed responses to future forcing, while Southern Indian Ocean activity projected to declineFuture changes in 10 m wind speed in coupled models are mixed, and models with lower bias suggest small increases

We describe the scientific and technical implementation of two models for a core set of\ud experiments contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6).\ud The models used are the physical atmosphere-land-ocean-sea ice model HadGEM3-GC3.1 and the\ud Earth system model UKESM1 which adds a carbon-nitrogen cycle and atmospheric chemistry to\ud HadGEM3-GC3.1. The model results are constrained by the external boundary conditions (forcing data)\ud and initial conditions.We outline the scientific rationale and assumptions made in specifying these.\ud Notable details of the implementation include an ozone redistribution scheme for prescribed ozone\ud simulations (HadGEM3-GC3.1) to avoid inconsistencies with the model's thermal tropopause, and land use\ud change in dynamic vegetation simulations (UKESM1) whose influence will be subject to potential biases in\ud the simulation of background natural vegetation.We discuss the implications of these decisions for\ud interpretation of the simulation results. These simulations are expensive in terms of human and CPU\ud resources and will underpin many further experiments; we describe some of the technical steps taken to\ud ensure their scientific robustness and reproducibility.

The PRIMAVERA project aims to develop a new generation of advanced and well evaluated high-resolution global climate models. An integral component of PRIMAVERA is a new set of simulations at standard and high-resolution from seven different European climate models. The expected data volume is 1.6 petabytes, which is comparable to the total volume of data in CMIP5. A comprehensive Data Management Plan (DMP) was developed to allow the distributed group of scientists to produce and analyse this volume of data during the project’s limited time duration. The DMP uses the approach of taking the analysis to the data. The simulations were run on HPCs across Europe and the data was transferred to the JASMIN super-data-cluster at the Rutherford Appleton Laboratory. A Data Management Tool (DMT) was developed to catalogue the available data and allow users to search through it using an intuitive web-based interface. The DMT allows users to request that the data they require is restored from tape to disk. The users are then able to perform all their analyses at JASMIN. The DMT also controls the publication of the data to the Earth System Grid Federation, making it available to the global community. Here we introduce JASMIN and the PRIMAVERA data management plan. We describe how the DMT allowed the project’s scientists to analyse this multi-model dataset. We describe how the tools and techniques developed can help future projects.

The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the three-dimensional ocean circulation that transports warm and salty water northward, and exports cold and dense water from the Arctic southward.The simulated AMOC in Coupled Model Intercomparison Project models (both coupled and ocean-only) has been studied extensively. However, correctly simulating the AMOC with these models remains a challenge for the climate modelling community. One model aspect that can affect the AMOC representation is the model resolution (i.e. grid spacing).Here, we examine key aspects of the North Atlantic Ocean circulation using a multi-model, multi-resolution ensemble based on the CMIP6 HighResMIP coupled experiments. The AMOC and associated heat transport tend to become stronger as model resolution increases, particularly when the ocean resolution changes from non-eddying to eddy-present and eddy-rich. However, the circulation remains too shallow compared to observations for most models, and this, together with temperature biases, cause the northward heat transport to be too low for a given overturning strength.In the period 2015-2050, the overturning circulation tends to decline more rapidly in the higher resolution models by more than 20% compared to the control state, which is related to both themean state and to the subpolar gyre contribution to deep water formation. The main part of the decline comes from the Florida Current component of the circulation.

In this study, we perform an evaluation of PRIMAVERA high-resolution (25–50 km) Global Climate Models (GCMs) relative to CORDEX Regional Climate Models (RCMs) over Europe (12–50 km resolutions). It is the first time such assessment is performed for regional climate information using ensembles of GCMs and RCMs at similar horizontal resolutions. We perform this exercise for the distribution of daily precipitation contributions to rainfall bins over Europe under current climate conditions. Both ensembles are evaluated against high quality national gridded observations in terms of resolution and station density. We show that PRIMAVERA GCMs simulate very similar distribution to CORDEX RCMs that CMIP5 cannot because of their coarse resolutions. PRIMAVERA and CORDEX ensembles generally show similar strengths and weaknesses. They are of good quality in summer and autumn in most European regions, but tend to overestimate precipitation in winter and spring. PRIMAVERA show improvements in the latter bias by reducing mid-rain rate biases in Central and Eastern Europe. Moreover, CORDEX simulate less light rainfall than PRIMAVERA in most regions and seasons, which improves this common GCM bias. Finally, PRIMAVERA simulate less heavy precipitation than CORDEX in most regions and seasons, especially in summer. PRIMAVERA appear to be closer to observations. However, when we apply an averaged precipitation undercatch error of 20 %, CORDEX become closer to these synthetic datasets. Considering 50 km resolution GCM or RCM datasets over Europe results in large benefits compared to CMIP5 models for impact studies at the regional scale. The effect of increasing resolution from 50 km to 12 km in CORDEX simulations is, in comparison, small in most regions and seasons outside mountainous regions (due to the importance of orography) and coastal regions (mostly depending on the resolution of the land-sea contrast). Now that GCMs are able to reach the level of information provided by CORDEX RCMs run at similar resolutions, there is an opportunity to better coordinate GCM and RCM simulations for future model intercomparison projects.

International audience; Finer grids in global climate models could lead to an improvement in the simulation of precipitation extremes. We assess the influence on model performance of increasing spatial resolution by evaluating pairs of high-and low-resolution forced atmospheric simulations from six global climate models (generally the latest CMIP6 version) on a common 1°× 1°grid. The differences in tuning between the lower and higher resolution versions are as limited as possible, which allows the influence of higher resolution to be assessed exclusively. We focus on the 1985-2014 climatology of annual extremes of daily precipitation over global land, and models are compared to observations from different sources (i.e., in situ-based and satellite-based) to enable consideration of observational uncertainty. Finally, we address regional features of model performance based on four indices characterizing different aspects of precipitation extremes. Our analysis highlights good agreement between models that precipitation extremes are more intense at higher resolution. We find that the spread among observations is substantial and can be as large as intermodel differences, which makes the quantitative evaluation of model performance difficult. However, consistently across the four precipitation extremes indices that we investigate, models often show lower skill at higher resolution compared to their corresponding lower resolution version. Our findings suggest that increasing spatial resolution alone is not sufficient to obtain a systematic improvement in the simulation of precipitation extremes, and other improvements (e.g., physics and tuning) may be required.

A multimodel, multiresolution ensemble using Coupled Model Intercomparison Project Phase 6 (CMIP6) High Resolution Model Intercomparison Project (HighResMIP) coupled experiments is used to assess the performance of key aspects of the North Atlantic circulation. The Atlantic Meridional Overturning Circulation (AMOC), and related heat transport, tends to become stronger as ocean model resolution is enhanced, better agreeing with observations at 26.5°N. However, for most models the circulation remains too shallow compared to observations and has a smaller temperature contrast between the northward and southward limbs of the AMOC. These biases cause the northward heat transport to be systematically too low for a given overturning strength. The higher‐resolution models also tend to have too much deep mixing in the subpolar gyre. In the period 2015–2050 the overturning circulation tends to decline more rapidly in the higher‐resolution models, which is related to both the mean state and to the subpolar gyre contribution to deep water formation. The main part of the decline comes from the Florida Current component of the circulation. Such large declines in AMOC are not seen in the models with resolutions more typically used for climate studies, suggesting an enhanced risk for Northern Hemisphere climate change. However, only a small number of different ocean models are included in the study. M. J. R., C. D. R., V. M., D. D., T. K., P. O., E. M.‐C., A. B., S. D., E. E., O. G., D. I., K. L., D. P., R. S., J. S., and L. T. acknowledge PRIMAVERA funding received from the European Commission under Grant Agreement 641727 of the Horizon 2020 research program. M. R., L. C. J., and H. H. were supported by the Met Office Hadley Centre Climate Programme funded by BEIS and Defra (GA01101). R. S. acknowledges funding from the National Environmental Research Council (NERC). A. C. acknowledges funding from the ACSIS project that is supported by the Natural Environment Research Council (Grant NE/N018044/1). XX acknowledges funding from the NOAA Climate Program Office MAPP Program (Award NA15OAR4310088). The CESM1.3 simulations are completed through the International Laboratory for High Resolution Earth System Prediction (iHESP)—a collaboration among QNLM, TAMU, and NCAR, from which Q. Z., P. C., S. G. Y., F. S. C., S. Z., and L. W. acknowledge funding and were performed on Frontera at the Texas Advanced Computing Center. NCAR is a major facility sponsored by the US National Science Foundation under Cooperative Agreement No. 1852977. Data from the RAPID‐MOCHA program are funded by the U.S. National Science Foundation and U.K. Natural Environment Research Council and are freely available at www.noc.soton.ac.uk/rapidmoc and https://mocha.rsmas.miami.edu/mocha/results/mocha-new/index.html websites. We acknowledge extensive use of the supercomputers at our institutes to complete the simulations and for the CEDA‐JASMIN platform to enable coordinated data storage and model analysis. The authors would like to thank all the teams involved in the EU H2020 PRIMAVERA project and iHESP for the hard work in configuring and executing model simulations and making the data available for analysis. They also thank two anonymous reviewers and the Editor for their helpful feedback to improve the manuscript.

The Coupled Model Intercomparison Project phase 6 (CMIP6) HighResMIP is a new experimental design for global climate model simulations that aims to assess the impact of model horizontal resolution on climate simulation fidelity. We describe a hierarchy of global coupled model resolutions based on the Hadley Centre Global Environment Model 3 – Global Coupled vn 3.1 (HadGEM3-GC3.1) model that ranges from an atmosphere–ocean resolution of 130 km–1∘ to 25 km–1∕12∘, all using the same forcings and initial conditions. In order to make such high-resolution simulations possible, the experiments have a short 30-year spinup, followed by at least century-long simulations with constant forcing to assess drift. We assess the change in model biases as a function of both atmosphere and ocean resolution, together with the effectiveness and robustness of this new experimental design. We find reductions in the biases in top-of-atmosphere radiation components and cloud forcing. There are significant reductions in some common surface climate model biases as resolution is increased, particularly in the Atlantic for sea surface temperature and precipitation, primarily driven by increased ocean resolution. There is also a reduction in drift from the initial conditions both at the surface and in the deeper ocean at higher resolution. Using an eddy-present and eddy-rich ocean resolution enhances the strength of the North Atlantic ocean circulation (boundary currents, overturning circulation and heat transport), while an eddy-present ocean resolution has a considerably reduced Antarctic Circumpolar Current strength. All models have a reasonable representation of El Niño–Southern Oscillation. In general, the biases present after 30 years of simulations do not change character markedly over longer timescales, justifying the experimental design.

ACTIVE magnetic bearings (AMBs) offer many advantages for momentum wheels on small satellites compared with conventional bearings using ball or roller bearings. Conventional bearings require a form of lubricant, which evaporates in the vacuum of space unless sealed, or to be made from a dry lubricant. The bearings will wear with time and may eventually fail, limiting the lifetime of the satellite. To minimize the wear on its bearings, the wheel may be operated at a low spin rate, limiting the angular momentum of thewheel. Using AMBsmeans that there is no contact between moving parts, and so lubrication is not required and wear is not an issue [1]. As the resolution of the cameras in small satellites approaches 1m ground resolution [2]microvibrations on the satellite increasingly affect the image quality. The bandwidth and precision of an AMB-based momentum wheel allow it to damp such microvibrations. The number of degrees of freedom that are actively controlled can be chosen. The 3-D wheel presented here has 5 degrees of freedom actively controlled. Because the tilt angle of the wheel is actively controlled, it is possible to tilt the wheel, generating a gyroscopic output torque in a similar fashion to a control moment gyro (CMG). Unlike a CMG, the tilt axis of the 3-D wheel is not fixed, and the gyroscopic output torque can be steered to be anywhere in the plane normal to the spin axis of the wheel. A single wheel is therefore capable of generating an output torque about all three principle axes of the spacecraft. Because the wheel is tilted using electromagnets, it can be tilted at a high rate, generating a large output torque. The bandwidth of the gyroscopic torque is higher than a conventional momentum wheel’s, making it ideal for the damping of microvibrations for highly sensitive payloads or for the rapid reorientation of spacecraft during maneuvers such as rendezvous and docking. In this Note we present the design of the engineering model of the 3-D wheel that has been built: a tilting magnetically levitated momentum-wheel for small satellites. We discuss the design of the wheel and then present the results of testing this engineering model. The position of thewheel can be controlled towithin 2:5 m and the tilt angle can be controlled with an accuracy of 0.1 mrad. The bandwidth of thewheel and controller is 120 rad=s. Thewheel can be tilted at a maximum rate of 0:56 rad=s, which when the wheel is spinning at 5000 rpm generates a gyroscopic output torque of 0:68 N m. The design is scalable; the diameter of the rotor can be increased for a larger moment of inertia and a greater torque generation capability. II. Wheel Design