Quantifying the role of diabatic processes for forecast errors associated with mid-latitude weather systems

English

Phase 1: Role of diabatic processes in the dynamics and predictability of extra-tropical cyclones

Heini Wernli, Jana Campa, Maxi Boettcher

Institut für Physik der Atmosphäre, Universität Mainz

Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland

Page and results of phase 1

Phase 2: Quantifying the role of diabatic processes for forecast errors associated with mid-latitude weather systems – A combined observational, diagnostic and modelling approach

Andreas Dörnbrack, Heini Wernli, Christian Grams, Andreas Schäfler

Institut für Physik der Atmosphäre, DLR Oberpfaffenhofen

Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland

Summary

Diabatic processes can strongly influence the evolution and intensity of midlatitude weather systems. These processes are associated with latent heat release due to phase transitions of water, surface fluxes, or radiative effects, and they strongly depend on the transport of water vapour that often occurs in narrow airstreams. It is difficult to quantitatively assess these processes from standard meteorological data. Therefore, this project will (1) use novel datasets from the YOTC project, humidity observations from field experiments, and numerical model techniques to better diagnose and quantify the role of theses processes for the evolution of different midlatitude weather systems, including cyclones, blockings, and jet streams. Investigating the forecast accuracy of these systems will (2) assess the relevance of diabatic processes for the quality of predicting high-impact weather events and help pinpointing potential shortcomings in the representation of these processes in NWP models. Results from (1 and 2) will provide the basis for a virtual field experiment (3) that will test the design of flight strategies for the planned international field experiment T-NAWDEX. Within this experiment, diabatic processes will be observed in key areas for improving the prediction of North Atlantic / European weather systems.

In the course of this project the planned virtual field experiment became the real T-NAWDEX Falcon field campaign (see WP B and WP C). During T-NAWDEX Falcon novel diagnostic tools and forecast products were successfully used and tested to prepare and perform Lagrangian measurements of diabatic processes in warm conveyor belts.

 

Current projects

 

WP A: "Quantification of diabatic processes in weather systems based upon ECMWF data" Christian Grams, Heini Wernli (ETH Zürich)

 

WP B:"Quantification of diabatic processes in weather systems based upon aircraft observations" Andreas Schäfler, Andreas Dörnbrack (DLR Oberpfaffenhofen)

 

WP C: T-NAWDEX Falcon measurement campaign