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Parameterization of Convective Transport in a Lagrangian Particle Dispersion Model and Its Evaluation

Forster, Caroline und Stohl, Andreas und Seibert, Petra (2007) Parameterization of Convective Transport in a Lagrangian Particle Dispersion Model and Its Evaluation. Journal of Applied Meteorology and Climatology, 46, Seiten 403-422. DOI: 10.1175/JAM2470.1.

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Kurzfassung

This paper presents the revision and evaluation of the interface between the convective parameterization by Emanuel and Živkovic´-Rothman and the Lagrangian particle dispersion model “FLEXPART” based on meteorological data from the European Centre for Medium-Range Weather Forecasts (ECMWF). The convection scheme relies on the ECMWF grid-scale temperature and humidity and provides a matrix necessary for the vertical convective particle displacement. The benefits of the revised interface relative to its previous version are presented. It is shown that, apart from minor fluctuations caused by the stochastic convective redistribution of the particles, the well-mixed criterion is fulfilled in simulations that include convection. Although for technical reasons the calculation of the displacement matrix differs somewhat between the forward and the backward simulations in time, the mean relative difference between the convective mass fluxes in forward and backward simulations is below 3% and can therefore be tolerated. A comparison of the convective mass fluxes and precipitation rates with those archived in the 40-yr ECMWF Reanalysis (ERA-40) data reveals that the convection scheme in FLEXPART produces upward mass fluxes and precipitation rates that are generally smaller by about 25% than those from ERA-40. This result is interpreted as positive, because precipitation is known to be overestimated by the ECMWF model. Tracer transport simulations with and without convection are compared with surface and aircraft measurements from two tracer experiments and to <sup>222</sup>Rn measurements from two aircraft campaigns. At the surface no substantial differences between the model runs with and without convection are found, but at higher altitudes the model runs with convection produced better agreement with the measurements in most of the cases and indifferent results in the others. However, for the tracer experiments only few measurements at higher altitudes are available, and for the aircraft campaigns the <sup>222</sup>Rn emissions are highly uncertain. Other datasets better suitable for the validation of convective transport in models are not available. Thus, there is a clear need for reliable datasets suitable to validate vertical transport in models.

Dokumentart:Zeitschriftenbeitrag
Titel:Parameterization of Convective Transport in a Lagrangian Particle Dispersion Model and Its Evaluation
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Forster, CarolineNICHT SPEZIFIZIERT
Stohl, AndreasNILU, Kjeller, N
Seibert, PetraUniv. of Natural Resources and Applied Life Sciences (BOKU), Vienna, A
Datum:2007
Erschienen in:Journal of Applied Meteorology and Climatology
Referierte Publikation:Ja
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:46
DOI :10.1175/JAM2470.1
Seitenbereich:Seiten 403-422
Status:veröffentlicht
Stichwörter:dispersion modelling, convection, convective parameterization, air pollution transport
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Luftfahrt
HGF - Programmthema:L VU - Luftverkehr und Umwelt (alt)
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L VU - Luftverkehr und Umwelt
DLR - Teilgebiet (Projekt, Vorhaben):L - Luftverkehr und Wetter (alt)
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Physik der Atmosphäre > Wolkenphysik und Verkehrsmeteorologie
Hinterlegt von: Jana Freund
Hinterlegt am:14 Jun 2007
Letzte Änderung:20 Okt 2014 14:31

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