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Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesPrecipitation frequency in MED and EURO-CORDEX ensembles from 0.44° to convective permitting resolution: Impact of model resolution and convection representation / Minh Ha-Truong (2022)
Titre : Precipitation frequency in MED and EURO-CORDEX ensembles from 0.44° to convective permitting resolution: Impact of model resolution and convection representation Type de document : Article/Communication Auteurs : Minh Ha-Truong, Auteur ; Sophie Bastin, Auteur ; Philippe Drobinski, Auteur ; Lluis Fita, Auteur ; Marjolaine Chiriaco, Auteur ; Jan Polcher, Auteur ; Olivier Bock Editeur : Research Square Année de publication : 2022 Projets : 3-projet - voir note / Importance : 1 p. Format : 21 x 30 cm Note générale : bibliographie
All authors gratefully acknowledge the WCRP-CORDEX-FPS on Convective phenomena at high resolution over Europe and the Mediterranean (FPSCONVALP- 3) and the research data exchange infrastructure and services provided by the Jülich Supercomputing Centre, Germany, as part of the Helmholtz Data Federation initiative. To process the data, this study benefited from the IPSL mesocenter ESPRI facility which is supported by CNRS, UPMC, Labex L-IPSL, CNES and EcolePolytechnique, and received funding from the HORIZON 2020 EUCP (European Climate Prediction System) project (https://www.eucp-project.eu, grant agreement No. 776613).Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] bassin méditerranéen
[Termes IGN] convection
[Termes IGN] données météorologiques
[Termes IGN] Europe (géographie politique)
[Termes IGN] modèle atmosphérique
[Termes IGN] orographie
[Termes IGN] précipitation
[Termes IGN] teneur intégrée en vapeur d'eauRésumé : (auteur) Recent studies using convection-permitting (CP) climate simulations have demonstrated a step-change in the representation of heavy rainfall and rainfall characteristics (frequency-intensity) compared to coarser resolution Global and Regional Climate models. The goal of this study is to better understand what explains the weaker frequency of precipitation in the CP ensemble by assessing the triggering process of precipitation in the different ensembles of regional climate simulations available over Europe. We focus on the statistical relationship between tropospheric temperature, humidity and precipitation to understand how the frequency of precipitation over Europe and the Mediterranean is impacted by model resolution and the representation of convection (parameterized vs. explicit). We employ a multi-model data-set with three different resolutions (0.44°, 0.11° and 0.0275°) produced in the context of the MED-CORDEX, EURO-CORDEX and the CORDEX Flagship Pilot Study "Convective Phenomena over Europe and the Mediterranean" (FPSCONV). The multi-variate approach is applied to all model ensembles, and to several surface stations where the integrated water vapor (IWV) is derived from Global Positioning System (GPS) measurements. The results show that all model ensembles capture the temperature dependence of the critical value of IWV (IWVcv), above which an increase in precipitation frequency occurs, but the differences between the models in terms of the value of IWVcv, and the probability of its being exceeded, can be large at higher temperatures. The lower frequency of precipitation in convection-permitting simulations is not only explained by higher temperatures but also by a higher IWVcv necessary to trigger precipitation at similar temperatures, and a lower probability to exceed this critical value. The spread between models in simulating IWVcv and the probability of exceeding IWVcv is reduced over land in the ensemble of models with explicit convection, especially at high temperatures, when the convective fraction of total precipitation becomes more important and the influence of the representation of entrainment in models thus becomes more important. Over lowlands, both model resolution and convection representation affect precipitation triggering while over mountainous areas, resolution has the highest impact due to orography-induced triggering processes. Over the sea, since lifting is produced by large-scale convergence, the probability to exceed IWVcv does not depend on temperature, and the model resolution does not have a clear impact on the results. Numéro de notice : P2022-003 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Preprint nature-HAL : Préprint DOI : 10.21203/rs.3.rs-1397006/v1 Date de publication en ligne : 25/02/2022 En ligne : https://doi.org/10.21203/rs.3.rs-1397006/v1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100754
Titre : A square-grid sampling support to reconcile systematicity and adaptivity in the periodic spatial survey of natural resources Type de document : Article/Communication Auteurs : Olivier Bouriaud Editeur : Research Square Année de publication : 2022 Projets : ARBRE / AgroParisTech (2007 -) Présentation : 24 p. Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] échantillonnage
[Termes IGN] grille d'échantillonnage
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] inventaire forestier national (données France)
[Termes IGN] placette d'échantillonnage
[Termes IGN] population
[Termes IGN] surveillance forestière
[Termes IGN] variation temporelle
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Spatially balanced sampling is the most efficient design for surveying continuous or spatial populations across space. The spatial sampling of large-scale surveys is mostly based on grids, whose properties drive, and potentially limit, the possibilities of building flexible samples. Conciliating spatial balance and flexibility remains difficult. In particular, periodicity causes high constraints to the sampling particularly when an increase in the frequency of the information delivery is sought. Sampling stratification of adaptive sampling intensity also conflicts the grid-based approach. We show that square grids have geometric homothetic properties that enable to answer these needs by supporting nested hierarchical subgrid sets. These properties can be exploited to cope with both spatial flexibility in the sampling effort and spatio-temporal coordination of samples. Whereas some surveys seemingly do exploit these properties practically across the world, no formal development has been made available in the survey sampling literature across fields of applications. Here we therefore define and demonstrate these properties, and show how they can be used to produce nested hierarchical grids compatible with multiple periodicity values of interest to natural monitoring, and with adapting sampling intensity across space and time. We also provide an original extension of this framework, intended to tune the sampling effort gradually while preserving spatial systematicity. We use the French National Forest Inventory survey to illustrate these properties and their use in a large-scale repeated inventory. We show the flexibility and diversity of sampling schemes that can be initiated with square grids and the limits of their use. Numéro de notice : P2022-004 Affiliation des auteurs : LIF (2020- ) Thématique : FORET/MATHEMATIQUE Nature : Article nature-HAL : Préprint DOI : 10.21203/rs.3.rs-1745991/v1 Date de publication en ligne : 08/07/2022 En ligne : https://doi.org/10.21203/rs.3.rs-1745991/v1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101265
