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SE13: Regional climate modelling at UGM meeting

We would like to draw your attention to a Special Session that will be held at the upcoming UGM  (http://www.ugm.org.mx/raugm/) meeting in Puerto Vallarta, Mexico, 30 October - 4 November 2016:

SE13: Regional climate modelling

In the last decade the study of the causes and effects of climate change, almost always supported by the integration of numerical models, has gained a social significance rarely seen in the history of modern science. Regional climate models have become a powerful tool to investigate the physical and dynamical processes of the atmosphere that regulate weather and climate. In recent years, the rapid growth of computational power has increased the potential and scope of such models, applied not only to the calculation of climate projections, but also to the generation of information for decision-makers.
This session will explore topics such as:

  1. The implementation and validation of regional climate models in various regions of the world.
  2. The use of regional climate models for the study of extreme hydrometeorological events: floods and droughts / cold and heat waves / tropical cyclones and tornadoes.
  3. Dynamical downscaling of global climate models for the different global warming scenarios reported in the IPCC Fifth Assessment Report.
  4. Studies of VIA (vulnerability, impacts and adaptation) to climate change
  5. Papers in English and Spanish will be received.

Deadline to submit abstracts: 07 August


Ruth Cerezo-Mota (rcerezom@iingen.unam.mx)
Cuauhtémoc Turrent Thompson (turrentc@cicese.mx)

Endorsed Flagship Pilot Studies


Five FPS propsals, out of nine, were selected from the first round of submissions and announced at the last day of the ICRC-CORDEX 2016 conference;

South America: Extreme precipitation events in Southeastern South America: a proposal for a better understanding and modeling

Contact person Maria Bettolli  bettolli@at.fcen.uba.ar

Southeastern South America (SESA) is a highly populated region where socio-economic activities are mainly based on rainfed agriculture and cattle rising, for   both domestic consumption and exports. The hydroelectric power utilities are also very important as they supply energy to the region and rivers provide the water for consumption.

SESA has   been characterized by a remarkable increment in the frequency and intensity of heavy precipitation events, particularly during the late 20th century. The region is particularly vulnerable to extreme events due to adaptation measures have not been performed at the same rate as changes in these extreme   events. However, it is still a challenge to better identify the factors and mechanisms that determine the location, intensity and frequency of the precipitation extremes and their large hydrologic impacts.

The main objectives of the SESA-FPS are to study multi-scale processes and interactions (convection, local, regional and remote processes, including the   co-behaviour of processes) that result in these extreme precipitation events; and to develop actionable climate information from multiple sources (statistical and dynamical downscaling products) based on co-production with the impact and user community.

This initiative seeks to promote inter-institutional collaboration and further networking, integrating not only South American research communities but also   European communities, taking into account that, in the recent years, there have been little or scattered activities related with inter-institutional coordinated regional climate modeling.

Multi-scale aspects, processes and interactions that result in extreme precipitation events will be investigated using dynamical models (high resolution, convection permitting and coupled models) and statistical models. ESD and RCM products will be compared and validated exploring the added value of downscaling. This will allow for a strengthened cooperation between ESD and RCM communities to jointly tackle key issues of regional climate change research. The impact of   heavy precipitations on flooding and soil moisture conditions will be assessed using a water balance model, and hydrological models will be used to   simulate ground water and soil moisture to drive crop models. In this   context, an increased cooperation and integration of RCM, ESD and VIA communities is expected towards a distillation of actionable information from multiple sources of downscaled products.

Data from RELAMPAGO, CHUVA and SALLJEX field campaigns will be available to perform the proposed studies, providing highly temporal-spatial resolution data to   characterize the synoptic scale, mesoscale, and convective scale flows in the region. Observed long records from surface meteorological and hydrological stations from different local institutions and the CLARIS-LPB initiative as well as a net of meteorological stations which includes the measurement of soil moisture at different levels will be available for calibration and validation of models (ESD, RCM, impact models.

Europe+ Mediterranean; Convective phenomena at high resolution over Europe and the Mediterranean

Contact person Erika Coppola coppolae@ictp.it or Stefan Sobolowski stefan.sobolowski@uni.no

Damaging weather events are often associated with extreme convective precipitation (Ducrocq et al. 2014). Convective cells occur due to rapidly ascending motions in areas of moisture convergence in regions of conditionally unstable atmospheric stratification. They can form anywhere in Europe and in Mediterranean areas, over homogeneous plains, or can develop from orographic barriers, land/sea or urban/rural contrasts. Convection induces a variety of potentially severe consequences such as heavy rainfall, flash floods, short-lived windstorms, hail and/or lightning.

Climate change potentially alters convection, making extreme precipitation more extreme, and also potentially modifying large-scale conditions (atmospheric circulation and stratification) making convection less or more favorable. This induces changes in return periods of precipitation extremes.

The study of convective precipitation events and their evolution under human-induced climate change is therefore of particular importance, and it is also timely:

  • Large field campaigns dedicated to the study of heavy precipitation events such as HyMeX (Ducrocq et al., 2014) and gridded high-resolution precipitation datasets (typically hourly, kilometer scale) , often merging station and radar data (Wüest et al. 2010, Delrieu et al. 2014) now provide a wealth of observations;
  • Computer capacity and model development now allow limited-area convection-permitting climate simulations at longer time-scales (Kendon et al., 2012, 2014; Ban et al., 2014, 2015, Leutwyler et al., http://www.c2sm.ethz.ch/research/crCLIM.html), enabeling a quantum jump in atmospheric climate modeling;
  • Homogeneous observation data sets collected over the years now unveil emerging trend signals in most extreme precipitations, particularly at sub-daily time scales (Westra et al., 2014) and in Mediterranean and Alpine mountain ranges (Vautard et al., 2015; Scherrer et al. 2016)
  • Several issues linked to detection, attribution, and downscaling of the very localized consequences of extreme convective events can now benefit from recent progress in advanced statistical methods combined with advances in dynamical modeling (Beaulant et al., 2011).

Convective extreme events are a priority under the WCRP Grand Challenge on climate extremes, because they carry both society-relevant and scientific challenges that can be tackled in the coming years. Further, "coordinated modeling programs are crucially needed to advance parameterizations of unresolved physics and to assess the full potential of CPMs" (Prein et al., 2015)

The proposal reflects a number of FPS criteria and aims to enlist research groups beyond the current CORDEX community. Present and future convective extremes and their processes will be investigated with models at convection-permitting resolutions over selected sub-regions of Europe and the Mediterranean. Advanced statistical techniques will also be employed in parallel to evaluate the performance of dynamical models and to, potentially, serve as emulators of convective extremes, as well as detect and attribute their changes. The added value of fine scale representation of convection will be rigorously evaluated with respect to both coarser resolution simulations up to GCM scales and VIA applications. The availability of observational datasets at very high resolutions in both space and time allows unprecedented evaluation opportunities. The FPS mobilizes the Euro- and Med-CORDEX communities and is also open to new partners who bring fresh perspectives and expertise to bear on issues surrounding convective phenomena.

Europe; Impact of land use changes on climate in Europe across spatial and temporal scales

Contact person Diana Rechid diana.rechid@hzg.de

We propose the Flagship Pilot Study "LUCAS" (Land Use & Climate Across Scales) for Europe, as a EURO-CORDEX & LUCID initiative supported by WCRP CORDEX and the GEWEX-GLASS international program. The spatial fragmentation of land use dynamics in Europe requires fine-scale modelling techniques, and their biophysical impacts on climate are often dominant on local to regional scales. Our overall objective is to identify robust biophysical impacts of land use changes (LUC) in Europe on climate across regional to local spatial scales and at various time scales from extreme events to multi-decadal:

  • Can local LUC attenuate negative impacts of climate change, e.g. extreme events in Europe?
  • What is the effect of spatial resolution on the magnitude and robustness of LUC-induced climate changes?
  • How large is the contribution of LUC to detected past and potential future climate trends in Europe?

In order to derive robust answers, we want to initiate a new era of coordinated regional climate model (RCM) ensemble LUC experiments on high spatial resolutions based on consistent land use dynamics for the past and the future. We include a new generation of RCMs, which couple regional atmosphere interactively with further components of the regional earth system, e.g. terrestrial biosphere and hydrosphere. The multi-model experiments shall be conducted over multiple gridded nests to refine the continental simulations down to resolutions below 5 km. Pilot regions are carefully chosen to a) evaluate the validity of coupled atmosphere-land simulations, b) better resolve the heterogeneity of land use changes in Europe and its local impacts on climate.

RCMs have been applied individually for investigating impacts of LUC on regional climate in different world regions (e.g. see reviews of Pielke et al. 2011, Mahmood et al. 2014). Most results are model specific and therefore do not allow one to derive robust conclusions and strategic directions. In this new initiative, for the first time an ensemble of RCMs will be used in coordinated experiments to inter-compare their sensitivities to LUC. Essential variables and fine-scale processes will be evaluated against multi-variable observations from flux towers, satellite sensors and new airborne and spaceborn radar techniques.

In our context, LUC refer to anthropogenic land cover changes as well as land management changes, as suggested by Luyssaert et al. (2014). The topic is of high societal relevance with respect to mitigation of global greenhouse gas emissions, e.g. through reforestation, and adaptation to local consequences of climate change, e.g. through irrigation of croplands. de Noblet-Ducoudré et al. (2012) demonstrated that regional impacts can be at least as important as greenhouse gas forcings, but biophysical feedbacks of land use changes on regional climate are still uncertain in magnitude and sign. There is an urgent need for robust information, which may help to prevent decisions on land management from unintended consequences.

We are prepared to build further collaborations with modelling activities over other CORDEX regions towards coordinated LUC experiments over multiple world regions.

Mediterranean; Role of the natural and anthropogenic aerosols in the Mediterranean region: past climate variability and future climate sensitivity

Contact person Solmon Fabien fsolmon@ictp.it or Marc Mallet marc.mallet@earo.obs-mip.fr

Aerosols strongly affect the Mediterranean basin located at the crossroads of air masses carrying both natural and anthropogenic particles making the basin an ideal    testbed for aerosol effects on climate. The aerosols have strong effects on the regional climate fluctuations from daily to multi-decadal scales due to    their direct, semi-direct and indirect effects on radiation, atmospheric circulation and cloud cover. Aerosols also represent one of the main sources of uncertainty in past    climate change attribution and future climate change projections at global and regional scales. Due to their relatively short life-time, aerosols    influencing the Mediterranean area are mostly produced in nearby regions and therefore they constitute a regional climate forcing of regional origin. In addition, the aerosols show a hig spatio-temporal variability and are influenced by numerous fine-scale processes. The use of high-resolution RCMs therefore fits well to address the four main scientific questions of the proposed FPS:

(1) Can we fully characterize the Mediterranean aerosol past variability and future evolution at climate scales ? in particular using RCMs.

(2) Can we understand the role of the Mediterranean aerosols on the past regional climate variability? including issues related to regional climate change    attribution and aerosols representation in climate models (GCM, RCM).  

(3) Can we determine the role of regionally-born aerosols in the Mediterranean future climate sensitivity ? in particular using RCMs as complementary approach to GCMs.  

(4) What is the aerosol role in shaping the Mediterranean extreme events ? (e.g. heat waves, heavy precipitation events)    

The proposed FPS will be facilitated by recent observation efforts such as the ChArMEx programme, long-term multi-variable super-sites, availability of new    homogenized datasets for AOD and surface shortwave and longwave radiations from in-situ coordinated networks (AERONET, GEBA, BRSN) and climate-aware satellite initiatives (ESA-CCI). 

The representation of aerosols and their effects in RCMs is still very crude and uncertain and a multi-model approach is therefore requested to bring robust answers to the scientific questions CORDEX then constitutes an adequate framework to propose scientifically-based and well-coordinated simulation protocols involving RCMs with various aerosol representations    

The proposed FPS targets in particular a better understanding of solar radiation variability and future changes. This is required to anticipate potential energy    production or to understand the level of production of existing sites. The FPS may therefore leads to new and innovative climate services for energy producers over the Euro-Mediterranean area. Another outcomes of the FPS concerns the marine biogeochemistry of the oligotrophic Mediterranean Sea ecosystem as particles constitute one of the main sources of regional nutrients.  

Besides, this FPS will contribute to several WCRP Grand Challenges, to the CORDEX Challenge about the coupled regional climate models and to the climate modelling activities of the Mediterranean regional programmes of Gewex (HyMeX) and CLIVAR (Med-CLIVAR).

Mediterranean; Role of the air-sea coupling and small scale ocean processess on regional climate

Contact person Gabriel Jordà gabriel.jorda@uib.cat or Gianmaria Sannino gianmaria.sannino@enea.it

The mechanisms through which air-sea coupling can modify the regional climate will be investigated in this FPS, with special emphasis on the role of small    scale ocean processes and waves. This FPS is a natural continuation of the activities of MedCORDEX, HyMeX and MedCLIVAR. The selected region is the    area surrounding the Mediterranean Sea, which is often referred to as an ocean in miniature due to the variety of processes occurring therein. These include strong air-sea interactions, active mesoscale and submesoscale dynamics and a permanent thermohaline overturning circulation. Moreover, this area is one of the best observed regions in the world. Besides the dense observational network of meteorological stations over Europe, the Mediterranean Sea is regularly sampled by different monitoring programs (e.g HyMeX, the regional component of Gewex) providing observations of the ocean-atmosphere coupled system over the last decades (Jordà et al., 2016). The Mediterranean region is therefore a particularly suitable candidate for this FPS.  

Ocean mesoscale in the Mediterranean Sea is characterized by a Rossby deformation radius of 5-10 km. In consequence, the SST often shows narrow and sharp fronts (e.g. in upwelling regions) as well as filaments with associated strong temperature gradients that can significantly modify the air-sea interaction (Chelton et al., 2004) and affect the climate evolution (Artale et al., 2009). Ocean mesoscale also plays a crucial role in the main mechanism of heat uptake by the ocean, namely dense water formation, which modelling requires both atmospheric (~25 km) and oceanic (~5-10 km) high spatial resolution that present GCMs are not able to achieve. Last, the Mediterranean wind-wave climate is characterized by high temporal and spatial variability due to the channeling of winds acting over the sea by the orography (Lionello et al. 2005). Wave effects on the turbulent heat fluxes are known to be important and the inclusion of this interaction in regional models is also expected to have a significant impact on long term simulations.   

A detailed analysis of how air-sea coupling at high resolution can modify the regional climate, and consequently the global climate, is still missing in the literature. There are some indications that it can provide an added value to RCMs in both present climate (Artale et al 2009, Nabat et al., 2015) and future scenarios (Somot et al., 2008), but the mechanisms nderlying such impact are not completely understood. Global climate modelling should therefore benefit from this FPS as it will give clues for the future design of GCMs.

This FPS will moreover provide to the broad community focusing on the impacts of climate change on marine environments (e.g. marine ecosystems, fisheries and coastal infrastructures including harbour operations, ocean energy harvesting, tourism activities and beach management ) a database of regional ocean and atmosphere projections which    consistency will be insured by the common robust protocol used for the simulations. ). This FPS should therefore have a great potential in terms of funding opportunities while insuring an efficient transfer of knowledge, insofar as many of end-users are already familiar with climate information.

World Oceans Day Portal of the Intergovernmental Oceanographic Commission (IOC) of UNESCO


The ocean plays a fundamental role in the global climate system, as it contributes largely to climate regulation by absorbing more than 25% of the carbon dioxide humans produce annually. It must therefore be considered as an essential part of mitigating climate change and solving climatic issues. Also, climate change deeply affects the marine environment, and preventing further climate change is important in order to maintain a healthy ocean. The mutual interaction between ocean and climate remains a key aspect of environmental science in order to tackle ecological problems. (read more)



CORDEX: The science that underpins future climate change policy

The Conference of Parties (COP) 21 in Paris in December 2015 agreed on a global effort to limit global warming to below 2°C compared to pre-industrial levels. Decision makers want to know the potential impacts of a 2°C global warming for different regions of the globe and different economic sectors. When planning for adaptation, policy makers need to understand the difference between global warming of 2°C and other climate change scenarios? Governments want to know what potential impacts can be prevented if global warming is limited to 2°C? There is a need for climate science to produce reliable and easy-to-understand information to specifically answer these questions.

Predicting future climate change is a complex task, requiring sophisticated numerical models and large teams of experts across many different disciplines. Every year significant improvements are made in high-resolution earth system modelling, to multi-model ensembles of both climate and impact projections and, particularly, in the bias correction of downscaled climate data. The WCRP Coordinated Regional Climate Downscaling Experiment (CORDEX) (http://www.cordex.org/) is working to address science-driven questions related to regional climate projection; identifying, quantifying and delivering high quality, reliable and accessible regional climate information.

impact2cCORDEX information feeds directly into policy-driven research. Take, for example, the IMPACT2C Project, which is a multi-disciplinary and international project providing information and evidence on the impacts of 2°C global warming. IMPACT2C includes model data from high-resolution (12.5 km) Euro-CORDEX (European branch of CORDEX) simulations. One of its outputs is the IMPACT2C web-atlas, which tells visual stories of the potential impacts of climate change with 2°C global warming for key sectors – energy, water, tourism, health, agriculture, ecosystems and forestry, as well as coastal and low-lying areas – at both the pan-European level and for some of the most vulnerable regions of the world to climate change.

IMPACT2C delivers a few key messages regarding our future with global warming of 2°C:

  • There will be large increases in extreme events for Europe, with much larger increases in daily maximum temperature over parts of Southern and South-Eastern, as well as increases in heavy precipitation across all of Europe.
  • It is expected that a global warming of 1.5°C (relative to pre-industrial levels) will be exceeded around or before 2040. In addition, almost all scenarios indicate that 2°C global warming is expected to be exceeded around or earlier than 2060.
  • Rates of climate change are likely to increase in the near future. Historical rates have averaged at just over 0.1°C per decade, but this could potentially increase to between 0.3°C and 0.7°C per decade over the next few decades. As much of Europe warms at a faster rate than the global average, this will mean even higher rates of change for some regions of Europe.

The project also considers the 2°C global warming benchmark as a precautionary level, which is likely to avoid the occurrence of extreme and potentially catastrophic events. These are referred to as tipping points or vulnerability hot spots and key examples are abrupt ice loss from the West Antarctic Ice Sheet or large-scale disintegration of the Greenland Ice Sheet.

The conclusions of IMPACT2C have major implications for possible adaptation strategies on national and international scales. This is the information that governments need to plan for the future and it would not be possible without the science that necessarily underpins it. To find out more about the application of CORDEX information see Daniela Jacob and Claas Teichmann’s presentation on ‘Climate Services in the frame of CORDEX’ (14.00 CEST, Session D1), streamed live (http://www.icrc-cordex2016.org) from Stockholm at the International Conference on Regional Climate (ICRC)-CORDEX 2016.

Flagship Pilot Studies

During the International Conference on Regional Climate - CORDEX 2013, a number of scientific challenges emerged including the need for:

  • More rigorous and quantitative assessment of the added value of regional downscaling;
  • Better understanding of processes and phenomena relevant for regional climate change;
  • A broader and more process-based assessment of downscaling techniques and models;
  • Better integration of Empirical-Statistical Downscaling (ESD) within the CORDEX framework;
  • Moving towards very high resolution, convection permitting models;
  • Development of coupled regional earth system models, in particular including the human component (e.g. urbanization, dams, pollution emissions, adaptation etc.)
  • Assessment of the effects of regional forcing, such as land-use change and aerosols;
  • Distillation of actionable information from multiple sources of downscaled projection information; and
  • Better integration of CORDEX with other WCRP programs (e.g. GEWEX)


It was recognised that addressing these scientific challenges might be problematic within the general CORDEX framework that employs standard sets of simulations for large domains often encompassing entire continents and surrounding regions. The idea thus emerged to develop more targeted experimental setups, called “Flagship Pilot Studies (FPS)”, which would enable the CORDEX communities to better address a number of the challenges outlined above.

The FPS will focus on sub-continental-scale targeted regions, so as to allow a number of capabilities towards addressing key scientific questions motivated by several issues:

  • Run RCMs at a broad range of resolutions, down to convection-permitting;
  • Promote side-by-side experimental design and evaluations of both statistical and dynamical downscaling techniques at scales more typical of VIA applications;
  • Design targeted experiments aimed at investigating specific regional processes and circulations;
  • Investigate the importance of regional scale forcings (aerosols, land-use change, vegetation etc);
  • Compile and use high quality, high resolution (both spatial and temporal), multi-variable observation datasets for model validation and analysis of processes;
  • Coordinate with specific activities in other WCRP projects, most notably the GEWEX regional hydroclimate projects;
  • Design end-to-end, climate-to-end-user, projects demonstrating the actionable value of downscaled climate change projections;
  • Increase the potential for funding by focusing on specific issues of interest for a certain region


In subsequent discussions, the CORDEX Scientific Advisory Team (CORDEX-SAT) recognised that, due to their very nature, FPSs cannot be conceived in general terms but should be driven by the regional CORDEX communities, although sharing common protocols so as to allow easier exchange of know-how. The SAT thus envisions a mechanism of solicitation of FPS proposals to be submitted by the regional communities and assessed by the SAT, with the aid of external experts, for formal CORDEX endorsement. The 'FPS Criteria & Guidelines' document serves to provide guidelines to enable these groups to develop FPS proposals for review and endorsement by the CORDEX SAT according to the criteria listed in the document.

How to submit a FPS proposal

  1. Review the full 'FPS Criteria & Guidelines' document carefully (download here)
  2. Complete the FPS application template (download here)
  3. Submit the completed application to the ipoc@cordex.org



There will be 3 deadlines per year for FPS proposals; 15th February, 15th June and 15th October. The third deadline for applications will be Saturday 15th October 2016 and the successful proposals from this round will be presented at the CORDEX web.



If you have any questions regarding the FPS proposal procedure please send them to ipoc@cordex.org