Perturbing the potential vorticity field in mesoscale forecasts of two
                        Mediterranean heavy precipitation events

Vich, M.; Romero, R.; Richard, Évelyne; Arbogast, Philippe; Maynard, K.

doi:10.3402/tellusa.v64i0.17224

Cited by 3 publications

(1 citation statement)

References 34 publications

(49 reference statements)

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“…A thorough verification of the results showed that even though all EPS are skilful and advantageous over a deterministic approach, both PV-perturbed systems beat a multiphysics approach, the PV gradient being the best. Vich et al (2012) introduced a novel concept consisting of building the ensemble members with the previous approach plus subjectively defined perturbations, drawn by a forecaster or an expert.…”

Section: Forecasting Methods: Testing Ensemble Prediction Systems (Eps)mentioning

confidence: 99%

MEDEX: a general overview

Jansà

Alpert

Arbogast

et al. 2014

Nat. Hazards Earth Syst. Sci.

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Abstract. The general objective of the international MEDiterranean EXperiment (MEDEX) was the better understanding and forecasting of cyclones that produce high impact weather in the Mediterranean. This paper reviews the motivation and foundation of MEDEX, the gestation, history and organisation of the project, as well as the main products and scientific achievements obtained from it. MEDEX obtained the approval of World Meteorological Organisation (WMO) and can be considered as framed within other WMO actions, such as the ALPine EXperiment (ALPEX), the Mediterranean Cyclones Study Project (MCP) and, to a certain extent, THe Observing System Research and Predictability EXperiment (THORPEX) and the HYdrological cycle in Mediterranean EXperiment (HyMeX). Through two phases (2000-2005 and 2006-2010), MEDEX has produced a specific database, with information about cyclones and severe or high impact weather events, several main reports and a specific data targeting system field campaign (DTS-MEDEX-2009). The scientific achievements are significant in fields like climatology, dynamical understanding of the physical processes and social impact of cyclones, as well as in aspects related to the location of sensitive zones for individual cases, the climatology of sensitivity zones and the improvement of the forecasts through innovative methods like mesoscale ensemble prediction systems.

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Section: Forecasting Methods: Testing Ensemble Prediction Systems (Eps)mentioning

confidence: 99%

MEDEX: a general overview

Jansà

Alpert

Arbogast

et al. 2014

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

Perturbing the potential vorticity field in mesoscale forecasts of two Mediterranean heavy precipitation events

Vich

Romero

Richard

et al. 2012

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C TIn order to improve the quality of the Mediterranean high-impact weather (HIW) numerical predictions, this study proposes to modify the potential vorticity (PV) field of the model initial state, taking advantage of information provided by the water vapour (WV) channel of the METEOSAT-7 satellite. The implemented PV field modifications aim to reduce the mismatch between the upper-level PV features and the WV brightness temperatures guided by the known relation between these two fields (PV-WV technique). The PV-WV technique effectiveness is evaluated on two HIW events, and is also compared with two additional PV modification techniques from an earlier study. The chosen episodes occurred on 9Á10 June 2000 and 9Á10 October 2002 and produced heavy precipitation over both Spain and France. The main difference between these two episodes is found in the driving mechanism, a mesoscale cyclone for the June 2000 event and a larger low-pressure centre for the October 2002 case. The two additional PV modification techniques introduce perturbations along the zones highlighted by the MM5 adjoint model calculated sensitivity zones (PV-adjoint) and along the three-dimensional PV structure presenting the locally most intense values and gradients of the field (PV-gradient). A close examination of both case studies of the forecast rainfall fields and several objective verification indices show that the PV-WV technique performance exceeds the control (or non-perturbed) forecast skill while remaining inside the distribution obtained by both PV-gradient and PV-adjoint techniques. This PV-WV technique could be used to increase the ensemble spread introducing higher amplitude modifications. Thus, a more skilled ensemble prediction system could be built by taking advantage of the subjectivity inherent to this method (manual perturbations) and also of the uncertainty present in the initial state.

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MEDEX: a general overview

Jansà¹,

Alpert²,

Arbogast³

et al. 2014

Preprint

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Abstract. The general objective of the international MEDiterranean EXperiment (MEDEX) was the better understanding and forecasting of cyclones that produce high impact weather in the Mediterranean. This paper reviews the motivation and foundation of MEDEX, the gestation, history and organisation of the project, as well as the main products and scientific achievements obtained from it. MEDEX obtained the approval of WMO and can be considered as framed within other WMO actions, such as ALPEX, MCP and, to certain extent, THORPEX and HyMeX. Through two phases (2000–2005 and 2006–2010) MEDEX has produced a specific database, with information about cyclones and high impact weather events, several main reports and a specific field campaign (DTS-MEDEX-2009). The scientific achievements are significant in fields like climatology, dynamical understanding of the physical processes and social impact of cyclones, as well as on aspects related to the location of sensitive zones for individual cases, climatology of sensitivity zones and the improvement of the forecasts through innovative methods like mesoscale ensemble prediction systems.

show abstract

Perturbing the potential vorticity field in mesoscale forecasts of two Mediterranean heavy precipitation events

Cited by 3 publications

References 34 publications

MEDEX: a general overview

MEDEX: a general overview

Perturbing the potential vorticity field in mesoscale forecasts of two Mediterranean heavy precipitation events

MEDEX: a general overview

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