HyMeX: A 10-Year Multidisciplinary Program on the Mediterranean Water Cycle

Drobinski, P. ... et. al.-- 20 pages, 10 figures, 1 table, supplement material http://journals.ametsoc.org/doi/suppl/10.1175/BAMS-D-12-00244.1HyMeX strives to improve our understanding of the Mediterranean water cycle, its variability from the weather-scale events to the seasonal and interannual scales, and its characteristics over one decade (2010–20), with a special focus on hydrometeorological extremes and the associated social and economic vulnerability of the Mediterranean territoriesHyMeX was developed by an international group of scientists and is currently funded by a large number of agencies. It has been the beneficiary of financial contributions from CNRS; Météo-France; CNES; IRSTEA; INRA; ANR; Collectivité Territoriale de Corse; KIT; CNR; Université de Toulouse; Grenoble Universités; EUMETSAT; EUMETNET; AEMet; Université Blaise Pascal, Clermont Ferrand; Université de la Méditerranée (Aix-Marseille II); Université Montpellier 2; CETEMPS; Italian Civil Protection Department; Université Paris- Sud 11; IGN; EPFL; NASA; New Mexico Tech; IFSTTAR; Mercator Ocean; NOAA; ENEA; TU Delft; CEA; ONERA; IMEDEA; SOCIB; ETH; MeteoCat; Consorzio LAMMA; IRD; National Observatory of Athens; Ministerio de Ciencia e Innovación; CIMA; BRGM; Wageningen University and Research Center; Department of Geophysics, University of Zagreb; Institute of Oceanography and Fisheries, Split, Croatia; INGV; OGS; Maroc Météo; DHMZ; ARPA Piemonte; ARPA-SIMC Emilia-Romagna; ARPA Calabria; ARPA Friuli Venezia Giulia; ARPA Liguria; ISPRA; University of Connecticut; Università degli Studi dell'Aquila; Università di Bologna; Università degli Studi di Torino; Università degli Studi della Basilicata; Università La Sapienza di Roma; Università degli Studi di Padova; Università del Salento; Universitat de Barcelona; Universitat de les Illes Balears; Universidad de Castilla-La Mancha; Universidad Complutense de Madrid; MeteoSwiss; and DLR. It also received support from the European Community's Seventh Framework Programme (e.g., PERSEUS, CLIM-RUN)Peer reviewe

Intérêt des observations du sondeur satellitaire TOVS pour l'analyse et la prévision des dépressions pendant FASTEX

Recent events have reminded us that it is still difficult to predict storms over Europe sufficiently in advance. The FASTEX (fronts and Atlantic storm-track experiment) campaign, conducted in January-February 1997, aims to improve storm forecasting. Our thesis work consisted in studying the interest of the TOVS (tiros-n operational vertical sounder) data on board NOAA satellites for the forecast of FASTEX cyclogeneses. Two research axis were explored: the use of TOVS brightness temperatures to detect upper air precursors to cyclogenesis and the study of their impact on numerical weather prediction. The temperature of the lower stratosphere (TLS) is obtained directly from the brightness temperatures and from additional information contained in the thermodynamical initial guess retrieval (TIGR) database of the lmd. TLS has been studied for 3 FASTEX lows and for the storms of late December 1999. We show that TLS, linked to the dynamic tropopause temperature, reflects tropopause structures such as ridges, thalwegs, tropopause breaks along the cyclonic side of the jet stream and upper air precursors. The TOVS brightness temperatures were then assimilated into the ARPEGE forecast model. For the first time, a targeting study with TOVS data has been performed. To quantify their impact on the forecast, we used the notion of forecast sensitivity to the observations: due to the presence of clouds over the sensitive areas and the key role of the tropopause in cyclogenesis, data from the TOVS microwave sounder are of primary importance as well as those from an infrared channel sounding below the tropopause. Furthermore, we have observed that the sensitivity is related to the assimilation process itself, suggesting the notion of an effective sensitive zone.L’actualité récente nous a rappelé qu'il est encore difficile de prévoir suffisamment a l'avance les tempêtes qui s'abattent sur l’Europe. La campagne FASTEX (fronts and atlantic storm-track experiment) menée en janvier-février 1997, a pour objectif d’améliorer la prévision de celles-ci. Notre travail de thèse a consiste à étudier l’intérêt des données du sondeur vertical TOVS (tiros-n operational vertical sounder) a bord des satellites de la NOAA pour la prévision des dépressions de FASTEX. Deux axes de recherche ont ete explores : l'utilisation des températures de brillance du TOVS pour déceler des précurseurs d'altitude aux cyclogenèses et l’étude de leur impact sur la prévision numérique du temps. La température de la basse stratosphère (TLS) est obtenue directement a l'aide des températures de brillance et d'une information complémentaire contenue dans la banque de données TIGR (thermodynamical initial guess retrieval) du LMD. TLS a été étudiée pour 3 dépressions de FASTEX et pour les tempêtes de fin décembre 1999. Nous avons montre que TLS, liée a la température de la tropopause dynamique, reflète des structures de la tropopause tels que dorsales, thalwegs, ruptures de tropopause le long du cote cyclonique du courant-jet et précurseurs d'altitude. Ensuite, les températures de brillance du TOVS ont été assimilées dans le modèle de prévision ARPEGE. Pour la première fois, une étude de ciblage avec les données du TOVS a été réalisée. Pour quantifier leur impact sur la prévision, nous avons utilise la notion de sensibilité de la prévision aux observations : en raison de la présence de nuages au dessus des zones sensibles et du rôle clé de la tropopause dans la cyclogenèse, les données du sondeur micro-ondes du TOVS sont primordiales ainsi que celles d'un canal infrarouge visant en dessous de la tropopause. De plus, nous avons observe que la sensibilité est liée au processus d'assimilation lui-même, suggérant la notion de zone sensible effective

Status of cloudy infrared radiance assimilation at Météo-France

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Preparing the assimilation of IASI-NG in NWP models: a first channel selection

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Synergistic approach of frozen hydrometeor retrievals: considerations on radiative transfer and model uncertainties in a simulated framework

International audienceAbstract. In cloudy situations, infrared (IR) and microwave (MW) observations are complementary, with infrared observations being sensitive to small cloud droplets and ice particles and with microwave observations being sensitive to precipitation. This complementarity can lead to fruitful synergies in precipitation science (e.g., Kidd and Levizzani, 2022). However, several sources of errors do exist in the treatment of infrared and microwave data that could prevent such synergy. This paper studies several of these sources to estimate their impact on retrievals. To do so, simulations from the radiative transfer (RT) for TIROS Operational Vertical Sounder (RTTOV v13) are used to build simulated observations. Indeed, we make use of a fully simulated framework to explain the impacts of the identified errors. A combination of infrared and microwave frequencies is built within a Bayesian inversion framework. Synergy is studied using different experiments: (i) with several sources of errors eliminated, (ii) with only one source of errors considered at a time and (iii) with all sources of errors together. The derived retrievals of frozen hydrometeors for each experiment are examined in a statistical study of 15 d in summer and 15 d in winter over the Atlantic Ocean. One of the main outcomes of the study is that the combination of infrared and microwave frequencies takes advantage of the strengths of both spectral ranges, leading to more accurate retrievals. Each source of error has more or less impact depending on the type of hydrometeor. Another outcome of the study is that, in all cases explored, even though the radiative transfer and numerical modeling errors may decrease the magnitude of benefits generated by the combination of infrared and microwave frequencies, the compromise remains positive

Assessment of the contribution of the Meteosat Third Generation Infrared Sounder (MTG-IRS) for the characterisation of ozone over Europe

International audienceIn the coming years, EUMETSAT's Meteosat Third Generation – Sounding (MTG-S) satellites will be launched with an instrument including valuable features on board. The MTG Infrared Sounder (MTG-IRS) will represent a major innovation for the monitoring of the chemical state of the atmosphere, since, at present, observations of these parameters mainly come from in situ measurements (geographically uneven) and from instruments on board polar-orbiting satellites (highly dependent on the scanning line of the satellite itself, which is limited, over a specific geographical area, to very few times per day). MTG-IRS will present a great deal of potential in the area of detecting different atmospheric species and will have the advantage of being based on a geostationary platform and acquiring data with a high temporal frequency (every 30 min over Europe), which makes it easier to track the transport of the species of interest. The present work aims to evaluate the potential impact, over a regional domain over Europe, of the assimilation of MTG-IRS radiances within a chemical transport model (CTM), Modèle de Chimie Atmosphérique de Grande Echelle (MOCAGE), operated by Météo-France. Since MTG-IRS is not yet in orbit, observations have been simulated using the observing system simulation experiment (OSSE) approach. Of the species to which MTG-IRS will be sensitive, the one treated in this study was ozone. The results obtained indicate that the assimilation of synthetic radiances of MTG-IRS always has a positive impact on the ozone analysis from MOCAGE. The relative average difference compared to the nature run (NR) in the ozone total columns improves from −30 % (no assimilation) to almost zero when MTG-IRS observations are available over the domain. Also remarkable is the reduction in the standard deviation of the difference with respect to the NR, which, in the area where MTG-IRS radiances are assimilated, reaches its lowest values (∼ 1.8 DU). When considering tropospheric columns, the improvement is also significant, from 15 %–20 % (no assimilation) down to 3 %. The error in the differences compared to the NR is lower than for total columns (minima ∼ 0.3 DU), due also to the lower concentrations of the tropospheric ozone field. Overall, the impact of assimilation is considerable over the whole vertical column: vertical variations are noticeably improved compared to what is obtained when no assimilation is performed (up to 25 % better)

Assimilation of GOES16 ABI radiances in ARPEGE model

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Contribution of the MTG/IRS radiance assimilation in the characterisation of the atmospheric chemical composition

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Homogeneity criteria from AVHRR information within IASI pixels in a numerical weather prediction context

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