L’estudi de la tramuntana: de J. M. Jansà al PYREX

La tramuntana és el vent dominant a Menorca i un dels més importants de la Mediterrània occidental. També és el responsable de la majoria dels temporals d’aquesta zona. J. M. Jansà va ésser un dels primers meteoròlegs que es va dedicar a estudiar aquest vent. Entre les seves contribucions cal destacar la climatologia del vent en altura i un minuciós estudi sobre la tramuntana a l’illa de Menorca. En aquest article es repassen la contribució de J. M. Jansà al coneixement de la tramuntana, així com els recents resultats que sobre aquest vent s’han obtingut de l’experiment PYREX

L'estudi de la tramuntana: de J.M. Jansà al PYREX

[CAT]La tramuntana és el vent dominant a Menorca i un dels més importants de la Mediterrània occidental. També és el responsable de la majoria dels temporals d’aquesta zona. J. M. Jansà va ésser un dels primers meteoròlegs que es va dedicar a estudiar aquest vent. Entre les seves contribucions cal destacar la climatologia del vent en altura i un minuciós estudi sobre la tramuntana a l’illa de Menorca. En aquest article es repassen la contribució de J. M. Jansà al coneixement de la tramuntana, així com els recents resultats que sobre aquest vent s’han obtingut de l’experiment PYREX.[EN]The Tramuntana is the strongest and most frequent wind of the Western Mediterranean, responsible for the greater part of gales in that area. J. M. Jansà was one of the pioneers of the study of the Tramuntana. Among his contributions, it can be distinguished the Climatology of the wind in the vertical and a precise study of the Tramuntana, both at Minorca Island. In this paper the contribution of J. M. Jansà to the knowledge of the Tramuntana wind is reviewed as well as the more recent results derived from PYREX Experiment

Impact of targeted observations on HIRLAM forecasts during HyMeX-SOP1

An adaptive observing system with terrestrial and space-based components has been explored, with the aim of improving numerical weather prediction skill in the Mediterranean. Four Observing System Experiments based on the HIRLAM system have been conducted to test the influence of targeted observations on short-term forecasts of high-impact weather events over the first Special Observation Period of the HyMeX international project. Extra radiosoundings and enhanced Advanced TIROS Operational Vertical Sounder (ATOVS) satellite observations are assimilated as targeted observations, and have been added to the baseline first separately and then jointly. In general, targeted observations have a positive but small impact on the short-term forecasts, noticeably at 700 to 500 hPa in all parameters and precipitation. Targeted radiosoundings produce a clear overall improvement of HIRLAM forecasts. Data targeting based only on satellite observations has a generally positive impact on precipitation, and in short-term forecasts of the rest of the parameters. The assimilation of both types of extra observations produces the highest and most statistically significant improvements. The magnitude of the impact on the forecasts depends on the weather regime that determines the location of sensitive areas. According to the diagnostics obtained from the data assimilation cycle, the targeted observations had a still larger positive influence on the subsequent analyses. Extra radiosoundings and additional satellite radiances clearly improve the first-guess quality over land and sea sensitive areas respectively.This work has been partially supported by PREDIMED (CLI-CGL2011-24458) Project

Intense storms in the Mediterranean: a first description from the ERA-40 perspective

The study of the Mediterranean cyclones from a climatological point of view has been one of the objectives of the first phase of WMO WWRP MEDEX (MEDiterranean EXperiment) project. It has been revealing itself like a good procedure for extracting conclusions about their characteristics and behaviour. The implementation on ECMWF ERA-40 reanalysis of the method for detecting and tracking the cyclones developed at the Centro Meteorológico Territorial (CMT) in Illes Balears of the Instituto Nacional de Meteorología (INM, Spain) has allowed the selection of the most intense storms occurred for the last 45 years. This selection has been based on the value of the cyclones' circulation. The areas of maximum intensification for those cyclones have been obtained and the existence of preferential zones of intensification has been verified. Finally a first sight of those cases has allowed to initiate the check up of the ability of the ERA-40 re-analyses for reproducing these intense Mediterranean storms

Three-dimensional structure of western Mediterranean cyclones

In the present paper, a method to objectively detect and track mean sea-level (MSL) cyclones for the western Mediterranean is described. Furthermore, the three-dimensional characterization of each MSL cyclone is performed by means of several parameters. This includes the vorticity, thermal and humidity fields at different pressure levels where the cyclone is detected, as well as the wind speed profile and the moist stability over the MSL cyclone. Both methodologies are illustrated and validated by a real case: an intense event of the well-known Genoa cyclone. Detection, tracking and three-dimensional characterization are applied to an 8-year (from June 1995 to May 2003) database of numerical analyses. The result is a MSL cyclone database for the western Mediterranean with a description of their three-dimensional structure. For a better analysis, cyclones are grouped in three different ways: by thickness, season and region of detection. Results show that western Mediterranean cyclones are located in specific geographical regions and that their location depends on the season. Several cyclones are weak and shallow, mainly because of thermal and/or orographic causes. On the contrary, other cyclones are large and intense and extend throughout the whole troposphere. Differences in cyclone structure depending on the location and season are also discusse

Assimilation of AMDAR humidity observations

Presentación realizada en: Joint 29th ALADIN Workshop & HIRLAM All Staff Meeting, celebrado del 1 al 5 de abril de 2019 en la Sede central de AEMET en Madrid