Intercomparison of Mid-Latitude Storm Diagnostics (IMILAST)

The IMILAST project systematically compares different cyclone detection and tracking methods, with the aim to comprehensively assess systematic uncertainties in mid-latitudinal storm identification and tracking.

Extratropical Cyclones near Iceland
Extratropical Cyclones near Iceland (Bild: Jesse Allen (NASA))
Extratropical Cyclones near Iceland
Extratropical Cyclones near Iceland (Bild: Jesse Allen (NASA))

Diagnostics of the observed and projection of the future changes of extratropical storms are a key issue e.g. for insurance companies, risk management and adaptation planning. Storm-associated damages are amongst the highest losses due to natural disasters in the mid-latitudes. Therefore the knowledge of the future variability and change in extratropical cyclone frequency, intensity and track locations is crucial for the strategic planning and minimization of the disaster impacts. Characteristics of cyclone activity may seriously depend on the methodology of cyclone identification and tracking. Linear trend magnitude and even sign might depend on the detection and tracking methods of the cyclones. Therefore, a special effort is needed to perform an intercomparison and to quantify these uncertainties. A proper knowledge about advantages and restrictions of different schemes must be obtained to be able to provide a synthesis of results rather than puzzling the scientific and the general public with apparently contradicing statements.

For users of storm track analyses and projections (including regional ones) it would be very helpful if the research community would provide information in a kind of "handbook" which provides definitions of what is meant by a "storm" or "cyclone" and a description of the available 10-15 different identification and tracking schemes as well as of the parameters used for the quantification of cyclone activity.

The project aims at providing a quantitative comprehensive assessment of all types of uncertainties inherent in the mid-latitudinal storm tracking by comparing different methodologies, and pointing out the informations that can be drawn from specific methods. The intercomparison can also provide a multi-method data set that could serve as a baseline for climate impact studies.

Working process

Unwetter über Bern am 8.6.2016

Method evaluation

Evaluation of the different identifications and tracking schemes.
Landnutzung Klimaportal

Intercomparison protocol

Application of its own tracking method to each predefined data set.

Data availability and Download

The track data of the second intercomparison project, which is the data used in the TELLUS A publications, are available to download for free use by the scientific community.

Kontakt und Koordination

Urs Neu
Swiss Academy of Sciences (SCNAT)
Laupenstrasse 7
3008 Bern
Tel.: +41 31 306 93 52

Project Description

gewitterstimmung see auenwald


Publications concerning the IMILAST project
IMILAST Workshop in Weggis

Sessions and presentations

Presentations at international meetings (EGU, WCRP) and project-specific workshops
ProClim Flash 68: Sturm oder nicht?
  • 2018

Sturm oder nicht?

Unterschiedliche Sturmdefinitionen haben Auswirkungen auf die Resultate von Klimafolgenstudien. Das zeigt ein von ProClim koordiniertes internationales Vergleichsexperiment.