References of "Scholzen, Chloé"
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See detailThe CORDEX.be initiative as a foundation for climate services in Belgium
Termonia, Piet; Van Schaeybroeck, Bert; De Cruz, Lesley et al

in Climate Services (2018), 11

The CORDEX.be project created the foundations for Belgian climate services by producing high-resolution Belgian climate information that (a) incorporates the expertise of the different Belgian climate ... [more ▼]

The CORDEX.be project created the foundations for Belgian climate services by producing high-resolution Belgian climate information that (a) incorporates the expertise of the different Belgian climate modeling groups and that (b) is consistent with the outcomes of the international CORDEX (“COordinated Regional Climate Downscaling Experiment”) project. The key practical tasks for the project were the coordination of activities among different Belgian climate groups, fostering the links to specific international initiatives and the creation of a stakeholder dialogue. Scientifically, the CORDEX.be project contributed to the EURO-CORDEX project, created a small ensemble of High-Resolution (H-Res) future projections over Belgium at convection-permitting resolutions and coupled these to seven Local Impact Models. Several impact studies have been carried out. The project also addressed some aspects of climate change uncertainties. The interactions and feedback from the stakeholder dialogue led to different practical applications at the Belgian national level [less ▲]

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See detailCombining regional downscaling expertise in Belgium: CORDEX and beyond
Termonia, Piet; Van Schaeybroeck, Bert; De Cruz, Lesley et al

Report (2018)

The main objectives of the CORDEX.be project were: 1. Contribute to the international climate community by participating to EURO-CORDEX by performing regional climate simulations over Europe. 2. Provide ... [more ▼]

The main objectives of the CORDEX.be project were: 1. Contribute to the international climate community by participating to EURO-CORDEX by performing regional climate simulations over Europe. 2. Provide an ensemble of High-Resolution (H-Res) climate simulations over Belgium i.e. to create a small ensemble of high-resolution future projections over Belgium at convectionpermitting resolutions. 3. Couple these model simulations to seven local-impact models for impact studies. 4. Present an overview of the ongoing climate modeling activities in Belgium. 5. Provide coherent climate information for Belgium targeted to end-users, backed by: (i) a unified framework for the H-Res climate runs and (ii) uncertainty estimations on the climate change signal; 6. Provide and present a climate-impact report for stakeholders and the general public that highlight the most important results of the project. [less ▲]

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See detailWinter season changes in Belgium: the MAR model contribution to the CORDEX.be project
Wyard, Coraline ULiege; Doutreloup, Sébastien ULiege; Scholzen, Chloé ULiege et al

Conference (2017, November 17)

In the framework of the CORDEX.be project funded by Belspo, most universities and research institutes of Belgium have worked together in order to gather existing and ongoing Belgian research activities in ... [more ▼]

In the framework of the CORDEX.be project funded by Belspo, most universities and research institutes of Belgium have worked together in order to gather existing and ongoing Belgian research activities in the domain of climate modelling to create a coherent scientific basis for future climate services in Belgium. The Laboratory of Climatology of the University of Liège has performed climate simulations using the regional climate model MAR (“Modèle Atmosphérique Régional” in French) at a resolution of 5 km over the period 1959-2014. This research aims to study the evolution of several variables computed by MAR during the winters of the last 50 years. Except in snow accumulation, results show no statistically significant trend in winter temperature or precipitation in Belgium. This results from the strong influence of natural large-scale/low-frequency oscillations in the atmospheric circulation in winter such as the North Atlantic Oscillation. [less ▲]

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See detailDecrease in climatic conditions favouring floods in the south-east of Belgium over 1959-2010 using the regional climate model MAR
Wyard, Coraline ULiege; Scholzen, Chloé ULiege; Fettweis, Xavier ULiege et al

in International Journal of Climatology (2017), 37(5), 27822796

The Ourthe River, in the south-east of Belgium, has a catchment area of 3,500 km2 and is one of the main tributaries of the Meuse River. In the Ourthe, most of the flood events occur during winter and ... [more ▼]

The Ourthe River, in the south-east of Belgium, has a catchment area of 3,500 km2 and is one of the main tributaries of the Meuse River. In the Ourthe, most of the flood events occur during winter and about 50% of them are due to heavy rainfall events combined to an abrupt melting of the snowpack covering the Ardennes massif during winter. This study aims to determine whether trends in extreme hydroclimatic events generating floods can be detected over the last century in Belgium, where a global warming signal can be observed. Hydroclimatic conditions favourable to floods were reconstructed over 1959- 2010 using the regional climate model MAR (“Modèle Atmosphérique Régional”) forced by the ERA-Interim/ERA-40, the ERA-20C and the NCEP/NCAR-v1 reanalyses. Extreme run-off events, which could potentially generate floods, were detected using run-off caused by precipitation events and snowpack melting from the MAR model. In the validation process, the MAR-driven temperature, precipitation and snow depth were successfully compared to daily weather data over the period 2008-2014 for 20 stations in Belgium. MAR also showed its ability to detect up to 90% of the hydroclimatic conditions which effectively generated observed floods in the Ourthe River over the period 1974- 2010. Conditions favourable to floods in the Ourthe River catchment present a negative trend over the period 1959-2010 as a result of a decrease in snow accumulation and a shortening of the snow season. This trend is expected to accelerate in a warmer climate. However, regarding the impact of the extreme precipitation events evolution on conditions favouring floods, the signal is less clear since the trends depend on the reanalysis used to force the MAR model. [less ▲]

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See detailHow reliable are the models to study recent climate change ? A study of heat/cold waves and radiative fluxes trends over 1900-2010 using the model MAR in Belgium
Wyard, Coraline ULiege; Fettweis, Xavier ULiege; Scholzen, Chloé ULiege

Poster (2016, August 29)

This research aims to assess the ability of the regional climate model MAR ("Modèle Atmosphérique Régional") to reconstruct the observed twentieth century climatology of extreme events and solar radiation ... [more ▼]

This research aims to assess the ability of the regional climate model MAR ("Modèle Atmosphérique Régional") to reconstruct the observed twentieth century climatology of extreme events and solar radiation in Belgium, as a necessary condition for reliable future projections. Simulations were performed by forcing MAR with several reanalyses: the ERA40/ERA-Interim, the ERA-20C and the NCEP/NCAR-v1. The results suggests that increasing air temperature would have generated decreasing relative humidity which would have lead to a decrease in cloudiness and an increase in solar downward radiation. This research illustrates the dependency between RCMs and their forcings. The forcing reanalyses can generate divergent trends while contrary to Global Climate Models (GCM), the reanalyses assimilate observations and are supposed to represent the same climate. [less ▲]

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See detailFirst steps of the regional climate model MAR over the Euro-CORDEX domain
Scholzen, Chloé ULiege; Fettweis, Xavier ULiege

Poster (2016, April)

In the framework of the Euro-CORDEX initiative, the Laboratory of Climatology of the University of Liège, Belgium, is currently using the regional climate model MAR (for “Modèle Atmosphérique Régional” ... [more ▼]

In the framework of the Euro-CORDEX initiative, the Laboratory of Climatology of the University of Liège, Belgium, is currently using the regional climate model MAR (for “Modèle Atmosphérique Régional”) to simulate the past, present and future climate over Europe. Simulations are to be performed for both available resolutions over the Euro-CORDEX domain, namely 0.11 deg. (12.5 km) and 0.44 deg. (50 km). Historical and present-day runs (1979-2015) will use the ERA-Interim and the NCEP/NCAR-v1 reanalyses as boundary conditions, whereas future projections will be driven by two selected GCMs from the CMIP5 database: NorESM1-M and MIROC5. All CMIP5-GCMs were previously compared against ERA-Interim reanalysis data in terms of their ability to represent the current mean climate over Europe. The GCMs also underwent a statistical classification based on the calculation of skill-scores evaluating for instance 850 hPa temperature and 500 hPa geopotential height. Several settings and parameters were tested in order to calibrate the regional climate model MAR over the Euro-CORDEX domain. MAR is to be validated against observations from the European Climate Assessment & Dataset (ECA&D). The final aim of this study is to assess the performance of MAR in comparing its results to other RCMs used within the Euro-CORDEX initiative. [less ▲]

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See detailStudy of the recent disappearance of a tropical glacier in the Bolivian Andes with the help of the high resolution regional climate model MAR
Scholzen, Chloé ULiege

Master's dissertation (2015)

This study provides a first evaluation of the MAR (Modèle Atmosphérique Régional) model over the Bolivian tropical Andes. MAR is currently developed at the ULg and allows dynamical downscaling up to 5 km ... [more ▼]

This study provides a first evaluation of the MAR (Modèle Atmosphérique Régional) model over the Bolivian tropical Andes. MAR is currently developed at the ULg and allows dynamical downscaling up to 5 km of horizontal resolution. The purpose of this work is to model the recent changes in the climatic parameters which are thought to control the mass and energy balance of mountain glaciers in the outer tropics. We focus on the recently vanished Chacaltaya Glacier (16°S), which by virtue of its location and its environmental context is representative of many small-sized glaciers of the Bolivian Andes. To evaluate our model, we first examine simulated precipitation and near-surface temperature against in situ observations from ground weather stations. Since observational data is very scarce in this part of the world, we also refer to qualitative information provided by the scientific literature. We compare the performance of the model forced with two different reanalyses, and with several corrections applied to the lateral boundary conditions (LBCs) impacting on temperature and humidity. MAR forced with the ERA-Interim reanalysis yields better results than with the NCEP/NCAR-v2 reanalysis. We then use the best ERA-driven simulation to assess the long-term climate change over 1960-2014 in the region of the Chacaltaya Mountain. The regional atmospheric circulation is adequately simulated by MAR, which reproduces the prevailing seasonal features of the lower, middle and upper troposphere. The climatic anomalies associated to the El Niño Southern Oscillation (ENSO) events are also properly recreated. Remaining model biases include an overall year-round dry bias over the Altiplano region, due to the strong corrections applied to the LBCs (-15% for humidity). Over the highest elevations of the Andes, both precipitation and cloud cover are probably overestimated by MAR. The sporadic spatial distribution of convective rainfall also suggests numerical instability in the convective parameterization scheme. Modeled temperatures match very well the observations, but the reliability of the observed time series is highly questionable. Between 1960 and 2014, the most significant trends concern precipitation and cloud cover which both decreased of about 35%. The surface radiation budget also changed as a result of the reduced cloudiness. Near-surface temperature increased by about 1.5°C. Those trends are believed to have been enhanced by the more frequent and more intense El Niño events during the warm Pacific Decadal Oscillation (PDO) phase between 1977 and 1999. The combination of the repeated droughts and the enhanced incoming short-wave radiation due to reduced low-level cloudiness are probably the main factors responsible for the acceleration of the Chacaltaya Glacier recession. Nevertheless, the ENSO signal is not always clear in the Bolivian Andes, because of the interference with strong local climatic processes. Moreover, additional forcings of non climatic nature may also be responsible for the rapid demise of the Chacaltaya Glacier. [less ▲]

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