References of "Fettweis, Xavier"
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See detailEvaluation des modèles climatiques régionaux MAR et WRF sur le Svalbard
Lang, Charlotte ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2012, September)

: Il est bien connu que les zones de hautes latitudes sont très sensibles aux changements climatiques. A cause du réchauffement global, la fonte des calottes a augmenté, ce qui à son tour a une influence ... [more ▼]

: Il est bien connu que les zones de hautes latitudes sont très sensibles aux changements climatiques. A cause du réchauffement global, la fonte des calottes a augmenté, ce qui à son tour a une influence sur le climat via des modifications de la circulation thermohaline, la rétroaction de l’albédo de la glace, l’augmentation du niveau des mers… Nous avons comparé le climat du Svalbard modélisé par deux modèles régionaux (MAR et WRF) à une résolution de 10 km sur la période 2000-2010 à des mesures provenant de plusieurs stations météorologiques localisées dans différentes régions de l’archipel afin d'évaluer lequel de ces modèles pouvait représenter au mieux le climat du Svalbard. [less ▲]

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See detailÉVOLUTION DU COMPORTEMENT DU VENT ET DE SON POTENTIEL POUR LA PRODUCTION D'ÉNERGIE ÉOLIENNE DURANT LES 30 DERNIÈRES ANNÉES : LE CAS DE LA BELGIQUE
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

in Bigot, Sylvain; Rome, Sandra (Eds.) Les climats régionaux : observation et modélisation. (Actes du colloque organisé à Grenoble du mercredi 5 au samedi 8 septembre 2012) (2012, September)

Chaque année, le nombre d'éoliennes dans le monde augmente de façon significative suite notamment aux politiques encourageant les productions d'énergie verte afin d’atténuer le réchauffement climatique ... [more ▼]

Chaque année, le nombre d'éoliennes dans le monde augmente de façon significative suite notamment aux politiques encourageant les productions d'énergie verte afin d’atténuer le réchauffement climatique. Toutefois, ce type d'énergie est tributaire de la météo. Cela implique que la production d'énergie éolienne est irrégulière à courte échelle de temps. Cependant, la disponibilité d’électricité de courtes périodes de temps est très importante à connaitre pour les producteurs d'énergie ainsi que pour les gestionnaires de réseaux. Pour ces raisons, il nous parait primordial d’analyser l’évolution de l’intermittence de la vitesse du vent sur les 30 dernières années (1979-2009). Pour ce faire nous utilisons le modèle WRF forcé par les réanalyses ERA-Interim, les réanalyses NCEP2 et certains modèles du GIEC (base de données CMIP5). [less ▲]

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See detailLes modèles globaux projettent-ils plus de blocages anticycloniques en Europe pour le futur ?
Belleflamme, Alexandre ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

in Bigot, Sylvain; Rome, Sandra (Eds.) XXVème colloque de l'Association Internationale de Climatologie - Les climats régionaux : observation et modélisation (2012, September)

The IPCC projects more frequent and longer heat waves and droughts during summer for future over Western Europe. These extreme events occur during anticyclonic blocking events. We use atmospheric ... [more ▼]

The IPCC projects more frequent and longer heat waves and droughts during summer for future over Western Europe. These extreme events occur during anticyclonic blocking events. We use atmospheric circulation type classifications to determine if the models project an increase of the number and the persistence of these anticyclonic blockings. For recent climate, the number of blocking events depends on the ability of the models to reproduce the observed general circulation. The future projections do not show any systematic evolution of the number of anticyclonic blockings over Western Europe. Nevertheless, other changes like an increase of the temperature will lead to more frequent heat waves and droughts. [less ▲]

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See detailGreenland climate change: from the past to the future
Masson‐Delmotte, Valérie; Swingedouw, Didier; Landais, Amaëlle et al

in Wiley Interdisciplinary Reviews. RNA (2012), 3(5), 427-449

Climate archives available from deep sea and marine shelf sediments, glaciers, lakes, and ice cores in and around Greenland allow us to place the current trends in regional climate, ice sheet dynamics ... [more ▼]

Climate archives available from deep sea and marine shelf sediments, glaciers, lakes, and ice cores in and around Greenland allow us to place the current trends in regional climate, ice sheet dynamics, and land surface changes in a broader perspective. We show that, during the last decade (2000s), atmospheric and sea surface temperatures are reaching levels last encountered millennia ago, when northern high latitude summer insolation was higher due to a different orbital configuration. Records from lake sediments in southern Greenland document major environmental and climatic conditions during the last 10,000 years, highlighting the role of soil dynamics in past vegetation changes, and stressing the growing anthropogenic impacts on soil erosion during the recent decades. Furthermore, past and present changes in atmospheric and oceanic heat advection appear to strongly influence both regional climate and ice sheet dynamics. Projections from climate models are investigated to quantify the magnitude and rates of future changes in Greenland temperature, which may be faster than past abrupt events occurring under interglacial conditions. Within one century, in response to increasing greenhouse gas emissions, Greenland may reach temperatures last time encountered during the last interglacial period, approximately 125,000 years ago. We review and discuss whether analogies between the last interglacial and future changes are reasonable, because of the different seasonal impacts of orbital and greenhouse gas forcings. Over several decades to centuries, future Greenland melt may act as a negative feedback, limiting regional warming albeit with global sea level and climatic impacts. [less ▲]

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See detailGreenland ice sheet albedo feedback: thermodynamics and atmospheric drivers
Box, J.; Fettweis, Xavier ULg; Stroeve, J. et al

in Cryosphere (The) (2012), 6

In this study, snowpack scenarios are modelled across the French Alps using dynamically downscaled variables from the ALADIN Regional Climate Model (RCM) for the control period (1961–1990) and three ... [more ▼]

In this study, snowpack scenarios are modelled across the French Alps using dynamically downscaled variables from the ALADIN Regional Climate Model (RCM) for the control period (1961–1990) and three emission scenarios (SRES B1, A1B and A2) for the mid- and late 21st century (2021–2050 and 2071–2100). These variables are statistically adapted to the different elevations, aspects and slopes of the Alpine massifs. For this purpose, we use a simple analogue criterion with ERA40 series as well as an existing detailed climatology of the French Alps (Durand et al., 2009a) that provides complete meteorological fields from the SAFRAN analysis model. The resulting scenarios of precipitation, temperature, wind, cloudiness, longwave and shortwave radiation, and humidity are used to run the physical snow model CROCUS and simulate snowpack evolution over the massifs studied. The seasonal and regional characteristics of the simulated climate and snow cover changes are explored, as is the influence of the scenarios on these changes. Preliminary results suggest that the snow water equivalent (SWE) of the snowpack will decrease dramatically in the next century, especially in the Southern and Extreme Southern parts of the Alps. This decrease seems to result primarily from a general warming throughout the year, and possibly a deficit of precipitation in the autumn. The magnitude of the snow cover decline follows a marked altitudinal gradient, with the highest altitudes being less exposed to climate change. Scenario A2, with its high concentrations of greenhouse gases, results in a SWE reduction roughly twice as large as in the low-emission scenario B1 by the end of the century. This study needs to be completed using simulations from other RCMs, since a multi-model approach is essential for uncertainty analysis. [less ▲]

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See detailRefreezing on the Greenland ice sheet: a comparison of parameterizations
Reijmer, C.; van den Broeke, M.; Fettweis, Xavier ULg et al

in Cryosphere (The) (2012), 6

Retention and refreezing of meltwater are acknowledged to be important processes for the mass budget of polar glaciers and ice sheets. Several parameterizations of these processes exist for use in energy ... [more ▼]

Retention and refreezing of meltwater are acknowledged to be important processes for the mass budget of polar glaciers and ice sheets. Several parameterizations of these processes exist for use in energy and mass balance models. Due to a lack of direct observations, validation of these parameterizations is difficult. In this study we compare a set of 6 refreezing parameterizations against output of two Regional Climate Models (RCMs) coupled to an energy balance snow model, the Regional Atmospheric Climate Model (RACMO2) and the Modèle Atmosphérique Régional (MAR), applied to the Greenland ice sheet. In both RCMs, refreezing is explicitly calculated in a snow model that calculates vertical profiles of temperature, density and liquid water content. Between RACMO2 and MAR, the ice sheet-integrated amount of refreezing differs by only 4.9 mm w.e yr−1 (4.5 %), and the temporal and spatial variability are very similar. For consistency, the parameterizations are forced with output (surface temperature, precipitation and melt) of the RCMs. For the ice sheet-integrated amount of refreezing and its inter-annual variations, all parameterizations give similar results, especially after some tuning. However, the spatial distributions differ significantly and the spatial correspondence between the RCMs is better than with any of the parameterizations. Results are especially sensitive to the choice of the depth of the thermally active layer, which determines the cold content of the snow in most parameterizations. These results are independent of which RCM is used to force the parameterizations. [less ▲]

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See detailImpact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990–2010, using the regional climate model MAR
Franco, Bruno ULg; Fettweis, Xavier ULg; Lang, Charlotte et al

in Cryosphere (The) (2012), 6

With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the ... [more ▼]

With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-INTERIM reanalysis. This comparison revealed that (i) the inter-annual variability of the SMB components is consistent within the different spatial resolutions investigated, (ii) the MAR model simulates heavier precipitation on average over the GrIS with diminishing spatial resolution, and (iii) the SMB components (except precipitation) can be derived from a simulation at lower resolution with an intelligent interpolation. This interpolation can also be used to approximate the SMB components over another topography/ice sheet mask of the GrIS. These results are important for the forcing of an ice dynamical model, needed to enable future projections of the GrIS contribution to sea level rise over the coming centuries. [less ▲]

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See detailEvaluation of the MAR and WRF regional climate models over Svalbard
Lang, Charlotte ULg; Fettweis, Xavier ULg; Doutreloup, Sébastien ULg et al

Conference (2012, June 01)

It is well known that high latitude zones are very sensitive to climate change. As a result of global warming, ice sheet melting has increased which in turn has an influence on climate through ... [more ▼]

It is well known that high latitude zones are very sensitive to climate change. As a result of global warming, ice sheet melting has increased which in turn has an influence on climate through modifications of the thermohaline circulation, feedback of ice albedo, sea level rise... Svalbard is an archipelago between 74 and 81°lat N and 60 percent of its area (62 248 km2) is covered with glaciers and ice sheets. The impact of global warming on the Svalbard cryosphere can be estimated with climate models. However, we need to use regional climate models as they offer the possibility of a higher resolution than general circulation models. We have ran two regional climate models (MAR and WRF) at a 10-kilometre resolution between 2006 and 2010 over Svalbard and compared their simulated climate to near surface measurements at several weather stations through the archipelago in order to determine which one of them could best represent the Svalbard climate. [less ▲]

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See detailAre the CMIP5 GCMs able to simulate atmospheric blocking situations over Europe ?
Belleflamme, Alexandre ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2012, April 26)

Some studies show that most General Circulation Models (GCMs) have difficulties to simulate the main observed circulation patterns and their frequencies. However, this does not only impact the GCM based ... [more ▼]

Some studies show that most General Circulation Models (GCMs) have difficulties to simulate the main observed circulation patterns and their frequencies. However, this does not only impact the GCM based projections for future climate, but also the results of downscaling methods using the circulation simulated by GCMs as forcing. Indeed, the downscaling methods are not able to correct the biases introduced by the GCM simulations in the free atmosphere. Here, we focus on the anticyclonic blocking situations over western Europe for summer (June, July and August). Indeed, these blocking situations, which are often related to droughts and heat waves, could become more frequent due to global warming. Moreover, their frequency and persistence depend on the variability of the circulation, which is known to be difficult to reproduce by the GCMs. In order to evaluate the ability of the GCMs to reproduce the observed frequency and persistence of blocking situations, we compare them with two reanalysis datasets (NCEP-NCAR 1 and ECMWF ERA-40) by using an automatic circulation type classification. The daily geopotential height at 500 hPa over the last 30 years of the current climate simulation (Historical experiment, 1976-2005) of all available CMIP5 GCMs prepared for the upcoming IPCC report AR5 is used here. The circulation type classification groups similar daily circulation situations together on basis of a leader-algorithm to obtain a few homogeneous circulation types describing the general circulation of the region. Thus, the frequency and the persistence of each circulation type can be analysed on a daily timescale. We show that the ability of the GCMs to reproduce the observed frequency and persistence of blocking situations is influenced by the anomalies in their circulation type frequency repartition. So, the GCMs which underestimate the frequency of the anticyclonic types tend to simulate less and shorter blocking situations. The contrary is observed for GCMs that overestimate the frequency of these circulation types. This rises questions about the reliability of the future projections for events related to blocking situations. Indeed, when applying the same approach as for the current climate to the future projections (experiments RCP4.5 and RCP8.5), it seems that the blocking situations become more frequent and persistent. However, when considering only the circulation patterns by removing the mean geopotential height increase due to global warming, there is no significant circulation change till 2100. This means that the GCMs conserve their circulation biases in spite of climate change and so, the frequency and the persistence of the blocking situations are projected to remain almost the same as those simulated for the current climate. [less ▲]

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See detailEvaluation of the regional climate model WRF over Svalbard
Lang, Charlotte ULg; Fettweis, Xavier ULg; Doutreloup, Sébastien ULg et al

Poster (2012, April 24)

It is well known that high latitude zones are very sensitive to climate change. As a result of global warming, ice sheet melting has increased which in turn has an influence on climate through ... [more ▼]

It is well known that high latitude zones are very sensitive to climate change. As a result of global warming, ice sheet melting has increased which in turn has an influence on climate through modifications of the thermohaline circulation, feedback of ice albedo, sea level rise, … Svalbard is an archipelago between 74 and 81°lat N and 60 percent of its area (62 248 km2) is covered with glaciers and ice sheets. The impact of global warming on the Svalbard cryosphere can be estimated with climate models. However, we need to use regional climate models as they offer the possibility of a higher resolution than general circulation models. We have ran two regional climate models (MAR and WRF) at a 10-kilometre resolution between 2006 and 2010 over Svalbard and compared their simulated climate to near surface measurements at several weather stations through the archipelago in order to determine which one of them could best represent the Svalbard climate. [less ▲]

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See detailEstimation, prévision et contrôle du gisement solaire en région wallonne
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2012, April 23)

Présentation des activités et des recherches du Laboratoire de Climatologie et Topoclimatologie de l'Université de Liège dans le domaine du rayonnement solaire

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See detailFuture projections of the Greenland ice sheet climate simulated by the regional climate model MAR forced by 2 CMIP5 global models.
Fettweis, Xavier ULg; Franco, Bruno ULg

Conference (2012, February 14)

As part of the ICE2SEA project, the regional climate model MAR was forced by the global models HadCM3 and ECHAM5 for making future projections of the Greenland Ice Sheet (GrIS) Surface Mass Balance (SMB ... [more ▼]

As part of the ICE2SEA project, the regional climate model MAR was forced by the global models HadCM3 and ECHAM5 for making future projections of the Greenland Ice Sheet (GrIS) Surface Mass Balance (SMB) over 1980-2099 at a resolution of 25km. However, the comparison with MAR forced by the ERA-40 reanalysis over 1980-1999 shows that MAR forced by these GCMs is not able to represent reliably the current SMB due to biases in the general circulation and in the free atmosphere summer temperature modelled by these GCMs around the GrIS. <br /> <br /> That is why, we present here first results of MAR forced by the next generation of GCMs from the CMIP5 data base (CanESM2 and NorESM1 here). The comparison with the ERA-40 forced MAR simulations over current climate is a lot of better, which increases the reliability and the interest of these new MAR projections. In addition, the new scenarios (RCP 2.6, 4.5, 6.0 and 8.5) of the next IPCC Assessment Report (AR5) are used here. These new simulations show notably that the response of SMB to rising temperature is not a linear function of the temperature anomalies due to the positive albedo feedback which accelerates the surface melt. For 2100, in case of extreme rising temperature (RCP 8.5 scenario), MAR simulates a surface GrIS mass loss corresponding to a cumulated sea level rise of about 15 cm since 2000! Mainly the changes in SMB and in surface energy balance will be discussed here. [less ▲]

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See detailMeasurement and modeling of ablation of the bottom of supraglacial lakes in western Greenland
Tedesco, Marco; Luthje, M.; Steffen, K. et al

in Geophysical Research Letters (2012), 39(L02502), 5

We report measurements of ablation rates of the bottom of two supraglacial lakes and of temperatures at different depths collected during the summers of 2010 and 2011 in west Greenland. To our knowledge ... [more ▼]

We report measurements of ablation rates of the bottom of two supraglacial lakes and of temperatures at different depths collected during the summers of 2010 and 2011 in west Greenland. To our knowledge, this is the first time that such data sets are reported and discussed in the literature. The measured ablation rates at the bottom of the two lakes are of the order of ∼6 cm/day, versus a rate of ∼2.5–3 cm/day in the case of bare ice of surrounding areas. Though our measurements suggest the presence of a vertical temperature gradient, it is not possible to draw final conclusions as the measured gradient is smaller than the accuracy of our temperature sensors. In-situ measurements are compared with the results of a thermodynamic model forced with the outputs of a regional climate model. In general, the model is able to satisfactorily reproduce the measured quantities with RMSE of the order of 3–4 cm for the ablation and ∼1.5°C in the case of water temperature. Our results confirm that the ablation at the bottom of supraglacial lakes plays an important role on the overall lake volume with the ablation in the case of ice covered by a lake being 110–135% of that over bare ice at nearby locations. Beside ice sheet hydrological implications, melting at the bottom of a supraglacial lake might affect estimates of lake volume from spaceborne visible and near-infrared measurements. [less ▲]

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See detailÉtude fréquentielle de données via la transformée en ondelette : application aux cycles climatiques
Mabille, Georges ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg et al

in Bulletin de la Société Géographique de Liège (2012), 58

Understanding the climate requires a complex study of time series connected to weather parameters. The climatologist frequently applies signal processing tools and often uses the harmonic analysis and the ... [more ▼]

Understanding the climate requires a complex study of time series connected to weather parameters. The climatologist frequently applies signal processing tools and often uses the harmonic analysis and the Fourier transform. This article is dedicated to the description of a new tool, elaborated by mathematicians, which completes the outfit of intruments intended for signal analysis. The scale spectrum, which synthetizes a part of the information supplied by the wavelet transform, possesses the property to reveal pseudo-cycles which evolves around an average period. When applied to air surface temperature time series obtained from more than one hundred weather stations, to reanalysis data and to climatic indices which characterize the tropospheric flows, the wavelet transforms and the scale spectra reveal cycles with periods close to 30 months and 42 months. The Solar parameters analysis also leads to the existence of pseudo-cycles with frequencies corresponding to those found in the temperature time series and climatic indices. [less ▲]

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See detailGreenland Ice Sheet - Arctic Report Card: Update for 2011
Box, J.; Cappelen, J.; Chen, C. et al

Report (2011)

A persistent and strong negative North Atlantic Oscillation (NAO) index was responsible for southerly air flow along the west of Greenland, which caused anomalously warm weather in winter 2010-11 and ... [more ▼]

A persistent and strong negative North Atlantic Oscillation (NAO) index was responsible for southerly air flow along the west of Greenland, which caused anomalously warm weather in winter 2010-11 and summer 2011. The area and duration of melting at the surface of the ice sheet in summer 2011 were the third highest since 1979. The lowest surface albedo observed in 12 years of satellite observations (2000-2011) was a consequence of enhanced surface melting and below normal summer snowfall. The area of marine-terminating glaciers continued to decrease, though at less than half the rate of the previous 10 years. In situ measurements revealed near record-setting mass losses concentrated at higher elevations on the western slope of the ice sheet, and at an isolated glacier in southeastern Greenland. Total ice sheet mass loss in 2011 was 70% larger than the 2003-09 average annual loss rate of -250 Gt y-1. According to satellite gravity data obtained since 2002, ice sheet mass loss is accelerating. [less ▲]

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See detailEvolution of wind behaviour and of its potential for wind power production in Belgium during the last 22 years : a comparison between WRF forced by NCEP2 reanalysis and WRF forced by ERA-INTERIM reanalysis
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Conference (2011, September 16)

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is ... [more ▼]

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is dependent on the weather. This implies that the wind production is irregular at a very short time scale. But the short time scale availability of the wind-based energy is important to the producers of energy as well as to the electric grid managers because the wind energy production can rise or fall rapidly which creates some financial and voltage variations. For these reasons, we study the past evolution of the availability of the wind quantity by analysing the intermittence of the wind speed in Belgium during the last 22 years (1989-2010). To reach this goal, we use the regional model WRF (Weather and Research Forecast model) developed by the UCAR community users. In a first time, the WRF model is forced by the NCEP2 reanalysis outputs to obtain a regionalisation of the weather conditions over a domain centred on Belgium at a resolution of 10 km. This resolution allows to capture the minute-based time scale variability of wind speed and consequently the irregular behaviour of the wind power production. In a second time, the WRF model is forced by the ERA-Interim reanalysis outputs with the same configuration. To obtain a value of the wind intermittence, we calculate the persistence of a wind blowing continuously with a minimum speed of 1 ms-1, then the persistence of a wind blowing continuously with a minimum speed of 2 ms-1, etc. The persistence of the wind speed and its evolution over 22 years are characterised by : (a) the mean wind speed over a fixed period (monthly, seasonally, … ), (b) the mean duration of a wind speed above x ms-1 over the same fixed period and (c) the evolution of (a) and (b) during the studied period. This analysis is made with the outputs of WRF-NCEP2 and with the outputs of WRF-Interim allowing to evaluate the impact of forcing fields into WRF-based wind climatology. [less ▲]

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See detailInfluence de la résolution spatiale sur la modélisation du bilan de masse en surface de la calotte glaciaire du Groenland
Franco, Bruno ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Conference (2011, September 07)

By using the regional climate model MAR (Modèle Atmosphérique Régional), we have modelled the Greenland Ice Sheet (GrIS) Surface Mass Balance (SMB) at 20, 25, 30, 40 and 50km resolution to assess the ... [more ▼]

By using the regional climate model MAR (Modèle Atmosphérique Régional), we have modelled the Greenland Ice Sheet (GrIS) Surface Mass Balance (SMB) at 20, 25, 30, 40 and 50km resolution to assess the impact of the spatial resolution. As part of the ICE2SEA project, the 25km-resolution SMB outputs of the MAR model are used as forcing fields for ice sheet models, in order to produce projections of the GrIS contribution to sea-level rise over the next 200 years. However, the ice sheet models often run at a higher resolution (typically 5-10km) than the current MAR resolution (25km). Such higher-resolution runs of the MAR model on the same integration domain generate a significant additional computing time and are not doable until now. That is why several enhanced SMB interpolations are tested here in order to reduce biases when interpolating the MAR outputs onto higher resolution, in the framework of the ICE2SEA project. [less ▲]

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See detailInfluences de l'environnement d'un parc éolien sur la prévision de sa production électrique à l'aide des modèles GFS (50km/3h) et WRF (2km/15min) : Le cas du parc éolien d'Amel (Haute-Belgique)
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

in Fazzini, Massimiliano; Beltrando, Gérard (Eds.) Actes du XXIVème Colloque International AIC : Climat Montagnard et Risques (2011, September 06)

The economic and climate contexts require to use more electricity from wind farms. However this kind of production is intermittent, therefore it is necessary to forecast this resource at least 1 day ahead ... [more ▼]

The economic and climate contexts require to use more electricity from wind farms. However this kind of production is intermittent, therefore it is necessary to forecast this resource at least 1 day ahead. Our laboratory has developed a forecasting model of wind-based electricity generation based on a global meteorological model (GFS) with a resolution of 50 km and 3 h. But this model has a resolution too coarse for a wind farm. So we have configured the regional model WRF with resolution of 2 km and 15 min to obtain better forecasts. Finally, the WRF model provides better forecasts, but both must be adjusted to take into account the direct environment of the wind farm. [less ▲]

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See detailCirculation atmosphérique simulée par les modèles de circulation générale en Europe de l'ouest : évaluation et projections futures
Belleflamme, Alexandre ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

in Fazzini, Massimiliano; Beltrando, Gérard (Eds.) XXIVème colloque de l'Association Internationale de Climatologie - Climat montagnard et risques (2011, September)

Atmospheric circulation simulations from general circulation models are used as forcing for downscaling methods and for future projections. Thus, it is essential to evaluate them. An automatic circulation ... [more ▼]

Atmospheric circulation simulations from general circulation models are used as forcing for downscaling methods and for future projections. Thus, it is essential to evaluate them. An automatic circulation type classification is applied to daily 500 hPa geopotential height data. Firstly, the classification is done for the NCEP-NCAR 1 reanalysis, and then the main circulation types are imposed to the simulations of six general circulation models. For recent climate (20C3M scenario), it appears that most models are not able to simulate well the circulation over western Europe, due to biases in the mean geopotential height and an underestimation of the circulation variability. For future climate (A1B scenario), a general increase of the geopotential height is projected, leading to the emergence of new circulation types. [less ▲]

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